0000950170-24-014934 | 10-K | XBRL Viewer

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Income Taxes - Summary of Gross Unrecognized Tax Benefits Excluding Interest and Penalties (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Balance as of January 1	$ 6,846	$ 6,084
Increases related to current year tax positions	655	697	$ 396
Increases related to prior year tax positions	242	65	5,688
Balance as of December 31	$ 7,743	$ 6,846	$ 6,084

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Summary of Activity Relating to Restricted Stock Units

The following table summarizes activity relating to time-based restricted stock units and performance restricted stock units:


	Shares			Weighted Average Grant Date Fair Value
Outstanding as of December 31, 2022		1,415,481		$	48.73
Granted		2,639,729		$	30.38
Vested		(326,530	)	$	51.06
Forfeited		(640,286	)	$	41.63
Outstanding as of December 31, 2023		3,088,394		$	34.27

Summary of Activity Relating to Time Based and Performance Based Stock Options

The following table summarizes activity related to time-based and performance-based stock options:


	Shares			Weighted Average Exercise Price		Weighted Average Remaining Life (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding as of December 31, 2022		7,788,350		$	77.95		6.36	$	7,275
Granted		964,253		$	44.58
Exercised		(65,940	)	$	16.58
Forfeited		(568,622	)	$	56.00
Outstanding as of December 31, 2023		8,118,041		$	76.02		5.66	$	475
Vested and expected to vest as of December 31, 2023		7,389,812		$	76.55		5.47	$	455
Exercisable as of December 31, 2023		6,116,989		$	81.94		4.84	$	403

Summary of Stock-Based Compensation Expense Recognized

The following table summarizes stock-based compensation expense recognized during the years ended December 31, 2023, 2022 and 2021:


	Year Ended December 31,
	2023		2022		2021
	(in thousands)
Research and development	$	24,813	$	25,888	$	49,746
Selling, general and administrative		47,716		35,714		54,883
Restructuring		838		—		—
	$	73,367	$	61,602	$	104,629

Summary of Stock-Based Compensation Expense by Award Type

The following table summarizes stock-based compensation expense by award type recognized during the years ended December 31, 2023, 2022 and 2021:


	Year Ended December 31,
	2023		2022		2021
	(in thousands)
Stock options	$	47,695	$	54,971	$	78,516
Restricted stock units		24,424		5,587		25,375
Employee stock purchase plan		1,248		1,044		738
	$	73,367	$	61,602	$	104,629

Summary of Weighted Average Assumptions Used to Compute Fair Value of Option Granted

The fair value of each stock option granted under the Company’s equity plans has been calculated on the date of grant using the following weighted average assumptions:


	Year Ended December 31,
	2023			2022			2021
Expected dividend yield		0	%		0	%		0	%
Expected volatility		72	%		73	%		76	%
Risk-free interest rate		3.85	%		2.49	%		0.63	%
Expected term	6.01 years			6.03 years			5.92 years

Fair Value Measurements

12 Months Ended

Dec. 31, 2023

Fair Value Disclosures [Abstract]

Fair Value Measurements

The Company’s cash equivalents are classified within Level 1 and Level 2 of the fair value hierarchy. The Company’s investments in marketable securities are classified within Level 2 of the fair value hierarchy.

The fair values of the Company’s marketable securities are based on prices obtained from independent pricing sources. Consistent with the fair value hierarchy described in Note 2, Summary of Significant Accounting Policies, marketable securities with validated quotes from pricing services are reflected within Level 2, as they are primarily based on observable pricing for similar assets or other market observable inputs. Typical inputs used by these pricing services include, but are not limited to, reported trades, benchmark yields, issuer spreads, bids, offers or estimates of cash flow, prepayment spreads and default rates. The Company performs validation procedures to ensure the reasonableness of this data. The Company performs its own review of prices received from the independent pricing services by comparing these

prices to other sources. After completing the validation procedures, the Company did not adjust or override any fair value measurements provided by the pricing services as of December 31, 2023 and 2022.

The following tables summarize the Company’s cash equivalents and marketable securities as of December 31, 2023 and 2022:


	December 31, 2023
	Total		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
	(in thousands)
Cash equivalents:
Money market funds	$	59,852	$	59,852	$	—	$	—
U.S. government securities		8,695		—		8,695		—
Total cash equivalents		68,547		59,852		8,695		—
Marketable securities:
U.S. government securities		166,925		—		166,925		—
U.S. corporate bonds		210,198		—		210,198		—
International corporate bonds		97,675		—		97,675		—
U.S. commercial paper		23,370		—		23,370		—
International commercial paper		46,900		—		46,900		—
U.S. certificates of deposit		8,830		—		8,830		—
U.S. municipal securities		128,294		—		128,294		—
Total marketable securities		682,192		—		682,192		—
	$	750,739	$	59,852	$	690,887	$	—


	December 31, 2022
	Total		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
	(in thousands)
Cash equivalents:
Money market funds	$	161,185	$	161,185	$	—	$	—
Total cash equivalents		161,185		161,185		—		—
Marketable securities:
U.S. government securities		302,911		—		302,911		—
U.S. corporate bonds		354,495		—		354,495		—
International corporate bonds		127,248		—		127,248		—
U.S. commercial paper		63,114		—		63,114		—
International commercial paper		133,163		—		133,163		—
U.S. certificates of deposit		15,613		—		15,613		—
U.S. municipal securities		113,250		—		113,250		—
Total marketable securities		1,109,794		—		1,109,794		—
	$	1,270,979	$	161,185	$	1,109,794	$	—

During the years ended December 31, 2023 and 2022, there were no transfers among the Level 1, Level 2 and Level 3 categories.

The following tables summarize the gross unrealized gains and losses of the Company’s marketable securities as of December 31, 2023 and 2022:


	December 31, 2023
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Credit Losses		Fair Value
	(in thousands)
Assets:
U.S. government securities	$	167,165	$	107	$	(347	)	$	—	$	166,925
U.S. corporate bonds		210,491		191		(484	)		—		210,198
International corporate bonds		97,698		99		(122	)		—		97,675
U.S. commercial paper		23,360		11		(1	)		—		23,370
International commercial paper		46,935		3		(38	)		—		46,900
U.S. certificates of deposit		8,830		—		—			—		8,830
U.S. municipal securities		128,527		26		(259	)		—		128,294
	$	683,006	$	437	$	(1,251	)	$	—	$	682,192


	December 31, 2022
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Credit Losses		Fair Value
	(in thousands)
Assets:
U.S. government securities	$	307,173	$	—	$	(4,262	)	$	—	$	302,911
U.S. corporate bonds		358,019		6		(3,530	)		—		354,495
International corporate bonds		128,374		7		(1,133	)		—		127,248
U.S. commercial paper		63,234		—		(120	)		—		63,114
International commercial paper		133,338		—		(175	)		—		133,163
U.S. certificates of deposit		15,613		—		—			—		15,613
U.S. municipal securities		114,249		31		(1,030	)		—		113,250
	$	1,120,000	$	44	$	(10,250	)	$	—	$	1,109,794

As of December 31, 2023 and 2022, the Company had $4.2 million of accrued interest receivable relating to the Company’s available-for-sale securities which is included within prepaid expenses and other current assets in the accompanying consolidated balance sheets. No accrued interest receivable was written off during the twelve months ended December 31, 2023 and 2022. Realized gains or losses were immaterial for the years ended December 31, 2023, 2022, and 2021.

The following tables summarize the fair value and the unrealized losses of the Company’s marketable securities that have been in a loss position for either less than twelve months or greater than twelve months as of December 31, 2023 and 2022:


	December 31, 2023
	Less than 12 months					Greater than 12 months					Total
	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
	(in thousands)
U.S. government securities	$	52,521	$	(96	)	$	41,911	$	(251	)	$	94,432	$	(347	)
U.S. corporate bonds		111,901		(246	)		43,851		(238	)		155,752		(484	)
International corporate bonds		43,708		(87	)		6,014		(35	)		49,722		(122	)
U.S. commercial paper		7,848		(1	)		—		—			7,848		(1	)
International commercial paper		37,300		(38	)		—		—			37,300		(38	)
U.S. municipal securities		90,095		(143	)		31,345		(116	)		121,440		(259	)
	$	343,373	$	(611	)	$	123,121	$	(640	)	$	466,494	$	(1,251	)


	December 31, 2022
	Less than 12 months					Greater than 12 months					Total
	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
	(in thousands)
U.S. government securities	$	112,243	$	(1,517	)	$	185,691	$	(2,745	)	$	297,934	$	(4,262	)
U.S. corporate bonds		208,507		(1,989	)		130,633		(1,541	)		339,140		(3,530	)
International corporate bonds		50,982		(497	)		68,993		(636	)		119,975		(1,133	)
U.S. commercial paper		24,768		(120	)		—		—			24,768		(120	)
International commercial paper		30,987		(175	)		—		—			30,987		(175	)
U.S. municipal securities		86,251		(497	)		14,466		(533	)		100,717		(1,030	)
	$	513,738	$	(4,795	)	$	399,783	$	(5,455	)	$	913,521	$	(10,250	)

As of December 31, 2023 and 2022, the unrealized losses on the Company’s investments in U.S. government securities, U.S. corporate bonds, international corporate bonds, and U.S. municipal securities were caused by interest rate increases. The Company purchased those investments at a premium relative to their face amount. The current credit ratings are all within the guidelines of the investment policy of the Company and the Company does not expect the issuers to settle any security at a price less than the amortized cost basis of the investment. The Company does not intend to sell the investments and it is not probable that the Company will be required to sell the investments before recovery of their amortized cost basis.

As of December 31, 2023, all marketable securities held by the Company had remaining contractual maturities of one year or less, except for U.S. government securities, U.S. corporate bonds, international corporate bonds and municipal securities with a fair value of $110.3 million that had maturities of one to two years.

As of December 31, 2022, all marketable securities held by the Company had remaining contractual maturities of one year or less, except for U.S. government securities, U.S. corporate bonds, international corporate bonds and municipal securities with a fair value of $211.2 million that had maturities of one to two years.

All marketable securities, including those with remaining contractual maturities of more than one year, are classified as current assets on the balance sheet because they are considered to be “available for sale” and the Company can convert them into cash to fund current operations.

There have been no impairments of the Company’s assets measured and carried at fair value during the years ended December 31, 2023 and 2022.

Net Loss Per Share - Summary of Potential Dilutive Securities Outstanding (Detail) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents	9,386,806	7,374,858	7,186,388
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents	7,663,041	7,138,350	6,599,429
Restricted Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents	1,662,363	160,403	563,334
Employee Stock Purchase Plan [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents	61,402	76,105	23,625

Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2023	Feb. 07, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Trading Symbol	SAGE
Entity Registrant Name	Sage Therapeutics, Inc.
Entity Central Index Key	0001597553
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction	false
Entity Common Stock, Shares Outstanding		60,106,687
Entity Public Float			$ 2,471,144,093
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Security Exchange Name	NASDAQ
Entity File Number	001-36544
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	27-4486580
Entity Address, Address Line One	215 First Street
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02142
City Area Code	617
Local Phone Number	299-8380
Document Annual Report	true
Document Transition Report	false
Auditor Name	PricewaterhouseCoopers LLP
Auditor Firm ID	238
Auditor Location	Boston, Massachusetts
Documents Incorporated by Reference	Part III of this Annual Report on Form 10-K incorporates by reference certain information from the registrant’s definitive Proxy Statement for its 2024 annual meeting of shareholders, which the registrant intends to file pursuant to Regulation 14A with the Securities and Exchange Commission not later than 120 days after the registrant’s fiscal year end of December 31, 2023. Except with respect to information specifically incorporated by reference in this Form 10-K, the Proxy Statement is not deemed to be filed as part of this Form 10-K.

Leases, Commitments and Contingencies - Schedule of Amounts of Operating Leases (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 13, 2021
Assets
Right-of-use operating asset	$ 4,458	$ 10,532	$ 3,700
Liabilities
Current operating lease liabilities	5,165	7,643
Long-term operating lease liabilities	0	4,491
Total operating lease liabilities	$ 5,165	$ 12,134

Net Loss Per Share - Summary of Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Numerator:
Net Income (Loss)	$ (541,489)	$ (532,784)	$ (457,892)
Denominator:
Weighted average number of common shares outstanding—basic	59,836,441	59,306,094	58,670,230
Weighted average common stock outstanding —diluted	59,836,441	59,306,094	58,670,230
Net loss per share - basic	$ (9.05)	$ (8.98)	$ (7.8)
Net loss per share - diluted	$ (9.05)	$ (8.98)	$ (7.8)

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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-Paragraph 1
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-Section 45
-Paragraph 7
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-URI https://asc.fasb.org//1943274/2147482689/260-10-45-7

+ Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

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+ Details

Employee Benefit Plan - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Postemployment Benefits [Abstract]
Employer matching contribution, percent of match	50.00%	50.00%	50.00%
Maximum annual contributions per employee, percent	6.00%	6.00%	6.00%
Employer contribution	$ 3.9	$ 3.0	$ 1.8
Defined Contribution Plan, Sponsor Location [Extensible Enumeration]	us-gaap:DomesticPlanMember	us-gaap:DomesticPlanMember	us-gaap:DomesticPlanMember
Defined Contribution Plan, Tax Status [Extensible Enumeration]	us-gaap:QualifiedPlanMember	us-gaap:QualifiedPlanMember	us-gaap:QualifiedPlanMember

Leases, Commitments and Contingencies - Operating Leases - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) ft²	Dec. 31, 2022 USD ($) ft²	Dec. 31, 2021 ft²	Dec. 13, 2021 USD ($)
Commitments And Contingencies [Line Items]
Operating lease option to extend	true
Operating lease renewal term	5 years
Right-of-use operating asset \| $	$ 4,458	$ 10,532		$ 3,700
Operating Lease One [Member]
Commitments And Contingencies [Line Items]
Office space rent under operating lease	63,017	63,017	63,017
Lease expire date	Aug. 31, 2024	Aug. 31, 2024	Aug. 31, 2024
Operating Lease Two [Member]
Commitments And Contingencies [Line Items]
Office space rent under operating lease	40,419	40,419	40,419
Lease expire date	Aug. 31, 2024	Aug. 31, 2024	Aug. 31, 2024
Operating Lease Three [Member]
Commitments And Contingencies [Line Items]
Office space rent under operating lease	15,525	15,525	15,525
Lease expire date	Nov. 30, 2024	Nov. 30, 2024	Nov. 30, 2024
Operating Lease Five [Member]
Commitments And Contingencies [Line Items]
Office space rent under operating lease	15,975	15,975	15,975
Lease expire date	Feb. 29, 2024	Feb. 29, 2024	Feb. 29, 2024
Maximum [Member]
Commitments And Contingencies [Line Items]
Operating lease remaining lease terms	1 year

Restructuring Additional Information (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Aug. 31, 2023	Dec. 31, 2023
Restructuring Costs [Abstract]
Percentage of workforce eliminated	40.00%
Restructuring expense		$ 33.4

Leases, Commitments and Contingencies

12 Months Ended

Dec. 31, 2023

Commitments and Contingencies Disclosure [Abstract]

Leases, Commitments and Contingencies

Operating Leases

The Company leases office space and certain equipment. All of the leases recorded on the consolidated balance sheets are operating leases. The Company’s leases have remaining lease terms of up to one year. Some of the leases include options to extend the leases for up to five years. These options were not included for the purpose of determining the right-of-use assets and associated lease liabilities as the Company determined that the renewal of these leases is not reasonably certain so only the original lease term was taken into consideration. The leases do not include any restrictions or covenants that had to be accounted for under the lease guidance.

During the fiscal years ended December 2021, 2022 and 2023, the Company leased office space in three multi-tenant buildings in Cambridge, Massachusetts, consisting of 63,017 square feet in the first building, under an operating lease that will expire on August 31, 2024; 40,419 square feet in the second building, under an operating lease that will expire on August 31, 2024 and 15,975 square feet in the third building, under an operating lease that began on March 1, 2019 and was initially scheduled to expire on February 29, 2024; and in a multi-tenant building in Raleigh, North Carolina, consisting of 15,525 square feet under an operating lease that will expire on November 30, 2024.

During the year ended December 31, 2021, the Company terminated the operating lease for office space in the third multi-tenant building in Cambridge, Massachusetts and the remaining right-of-use asset of $3.7 million and the associated liabilities related to this lease were de-recognized upon termination of the lease. Additionally, during the year ended December 31, 2021, the Company entered into a sublease for a portion of the leased office space in the second multi-tenant building in Cambridge, Massachusetts.

The following table shows the amounts of operating leases in the balance sheets as of December 31, 2023 and 2022:


		December 31,
Balance sheet location	Balance sheet caption	2023		2022
		(in thousands)
Assets
Right-of-use operating asset	Right-of-use operating asset	$	4,458	$	10,532

Liabilities
Current operating lease liabilities	Operating lease liability, current portion		5,165		7,643
Long-term operating lease liabilities	Operating lease liability, net of current portion		—		4,491
		$	5,165	$	12,134

The following table shows the amounts of lease expense by lease type that was recognized during the years ended December 31, 2023, 2022 and 2021:


	Year Ended December 31,
	2023			2022			2021
	(in thousands)
Operating lease cost	$	6,748		$	6,748		$	8,748
Variable lease cost		1,957			1,846			1,600
Short-term lease cost		20			206			101
Sublease income		(434	)		(421	)		(234	)
	$	8,291		$	8,379		$	10,215

The Company made an accounting policy election not to apply the recognition requirements to short-term leases. The Company recognizes the lease payments for short-term leases as expense on a straight-line basis over the lease term, and variable lease payments in the period in which the obligation for those payments is incurred.

The minimum lease payments are expected to be as follows:


Years Ending December 31,	(In thousands)
2024	$	5,316
Thereafter		—
Total lease payments		5,316
Less imputed interest		(151	)
Present value of operating lease liabilities	$	5,165

The following table shows the weighted average remaining lease term and weighted average discount rate of the operating leases:


	Year ended December 31,
	2023	2022
Weighted average remaining lease term in years	0.69	1.68
Weighted average discount rate	7.5%	7.5%

The interest rate implicit in lease contracts is typically not readily determinable and as such, the Company uses its incremental borrowing rate based on the information available at the lease commencement date, which represents an internally developed rate that would be incurred to borrow, on a collateralized basis, over a similar term, an amount equal to the lease payments in a similar economic environment.

The following table shows the supplemental disclosure of cash flow information related to the operating leases included in cash flows used by operating activities in the consolidated statements of cash flows:


	Year Ended December 31,
	2023		2022		2021
	(in thousands)
Cash paid for amounts included in the measurement of lease liabilities	$	7,643	$	7,468	$	9,264

Lease asset de-recognized upon lease cancellation
Operating leases	$	—	$	—	$	3,733

License Agreements

CyDex License Agreement

In September 2015, the Company amended and restated its existing commercial license agreement with CyDex Pharmaceuticals, Inc. (“CyDex”), a wholly owned subsidiary of Ligand Pharmaceuticals Incorporated.

Under the terms of the commercial license agreement as amended and restated, CyDex has granted to the Company an exclusive license to CyDex’s Captisol drug formulation technology and related intellectual property for the manufacture of pharmaceutical products incorporating brexanolone and the Company’s compound known as SAGE-689, and the development and commercialization of the resulting products for the treatment, prevention or diagnosis of any disease or symptom in humans or animals other than (i) the ocular treatment of any disease or condition with a formulation, including a hormone; (ii) topical ocular treatment of inflammatory conditions; (iii) treatment and prophylaxis of fungal infections in humans; and (iv) any ocular treatment for retinal degeneration. The Company is required to pay a royalty to CyDex on sales of brexanolone and will be required to pay a royalty on any sales of SAGE-689, if such product candidate is successfully developed in the future. Royalty rates are in the low single digits based on levels of net sales. From the effective date of the agreement to December 31, 2023, the Company has paid to CyDex $1.0 million for licensing fees, which was recorded as research and development expense.

Under the amended and restated license agreement with CyDex, the Company agreed to make milestone payments on the achievement of clinical development and regulatory milestones in the amount of up to $0.8 million in clinical milestones and up to $3.8 million in regulatory milestones for each of the first two fields with respect to brexanolone; up to $1.3 million in clinical milestones and up to $8.5 million in regulatory milestones for each of the third and fourth fields with respect to brexanolone; and up to $0.8 million in clinical milestones and up to $1.8 million in regulatory milestones for one field with respect to SAGE-689. From the effective date of the agreement to December 31, 2023, the Company has recorded research and development expense and made cash payments of $3.6 million related to these clinical development and regulatory milestones and has recorded an intangible asset and made a cash payment of $3.0 million related to these regulatory milestones.

For the year ended December 31, 2021, an additional clinical development milestone was met under the license agreement with CyDex related to SAGE-689, and accordingly, the Company recorded research and development expense and made a cash payment of $0.1 million. Additionally in the year ended December 31, 2021, the Company paid $1.3 million for the additional clinical development milestones that were met for the brexanolone program under the license agreement with CyDex in the year ended December 31, 2020.

For the years ended December 31, 2023 and 2022, the Company did not record any expense or intangible asset, or make any milestone payments related to clinical development or regulatory milestones for the brexanolone program or SAGE-689 under the license agreement with CyDex.

University of California License Agreements

In October 2013, the Company entered into a non-exclusive license agreement with the Regents of the University of California (“the Regents”) under which the Company was granted a non-exclusive license to certain clinical data and clinical material related to brexanolone for use in the development and commercialization of biopharmaceutical products in the licensed field, including status epilepticus and postpartum depression. In May 2014, the license agreement was amended to add the treatment of essential tremor to the licensed field of use, materials and milestone fee provisions of the agreement. The Company paid to the Regents clinical development milestones of $0.1 million, prior to December 31, 2015; no other milestones are outstanding under this non-exclusive license agreement. The Company is required to pay royalties of less than 1% on net sales for a period of fifteen years following the sale of the first product developed using the data and materials, and the Company began to pay these royalties in 2019. The license will terminate on the earlier to occur of (i) 27 years after the effective date or (ii) 15 years after the last-derived product is first commercially sold.

In June 2015, the Company entered into an exclusive license agreement with the Regents whereby the Company was granted an exclusive license to certain patent rights related to the use of allopregnanolone to treat various diseases. In exchange for such license, the Company paid an upfront payment of $50,000 and was required to make payments of $15,000 for annual maintenance fees until the calendar year following the first sale of ZULRESSO. The Company is obligated to make milestone payments following the achievement of specified regulatory and sales milestones of up to $0.7 million and $2.0 million in the aggregate, respectively. The Company pays royalties at a low single digit percentage of net sales of ZULRESSO, subject to specified minimum annual royalty amounts. Unless terminated by operation of law or by acts of the parties under the terms of the agreement, the license agreement will terminate when the last-to-expire patents or last-to-be abandoned patent applications expire, whichever is later. From the effective date of the agreement to December 31, 2023, the Company has recorded research and development expense and made cash payments of $0.3 million related to these regulatory and sales milestones; and has recorded an intangible asset and made a cash payment of $0.5 million related to these regulatory and sales milestones.

For the years ended December 31, 2023, 2022 and 2021, the Company did not record any expense or make any milestone payments under the license agreements with the Regents.

Common Stock

12 Months Ended

Dec. 31, 2023

Text Block [Abstract]

Common Stock

As of December 31, 2023 and 2022, the Company authorized 120,000,000 shares of common stock with a par value of $0.0001 per share.

Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders. Common stockholders are entitled to receive dividends, as may be declared by the Board, if any. As of December 31, 2023 and 2022, no dividends have been declared.

As of December 31, 2023, the Company had received 3,033 shares of the Company’s common stock from a then-employee as consideration for exercises of stock options. The total cost of shares held in treasury at December 31, 2023 was $0.4 million.

Sales Agreement

On November 7, 2023, the Company entered into a Sales Agreement (the “Sales Agreement”) with Cowen and Company, LLC, as sales agent (“Cowen”), with respect to an “at the market offering” program pursuant to which the Company may offer and sell shares of its common stock having an aggregate offering price of up to $250.0 million (the “Shares”), from time to time through Cowen (the “ATM Offering”).

Upon delivery of a placement notice, and subject to the terms and conditions of the Sales Agreement, Cowen may sell the Shares by methods deemed to be an “at the market offering” as defined in Rule 415(a)(4) promulgated under the Securities Act of 1933, as amended. The Company may sell shares in amounts and at times to be determined by the Company from time to time subject to the terms and conditions of the Sales Agreement, but the Company has no obligation to sell any of the Shares in the ATM Offering.

The Company or Cowen may suspend or terminate the offering of Shares upon notice to the other parties and subject to other conditions. The Sales Agreement provides that Cowen will be entitled to a sales commission of up to 3.0% of the gross sales price per share of all shares sold under the ATM Offering. The Company has also agreed to provide Cowen with customary indemnification and contribution rights.

During the year ended December 31, 2023, the Company did not sell any shares under the Sales Agreement.

Summary of Significant Accounting Policies	12 Months Ended
Summary of Significant Accounting Policies	Dec. 31, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies The following is a summary of significant accounting policies followed in the preparation of these consolidated financial statements. Basis of Presentation The accompanying consolidated financial statements include those of the Company and its subsidiaries after elimination of all intercompany accounts and transactions. The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the U.S. (“GAAP”). Principles of Consolidation The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. Intercompany accounts and transactions have been eliminated. Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Cash Equivalents The Company considers all highly liquid investments with an original maturity of 90 days or less to be cash equivalents. As of December 31, 2023, cash equivalents were comprised of money market funds and U.S. government securities. As of December 31, 2022, cash equivalents were comprised of money market funds. Marketable Securities Marketable securities consist of investments with original maturities greater than 90 days. The Company has classified its investments with maturities beyond one year as short-term, based on their highly liquid nature and because such marketable securities represent the investment of cash that is available for current operations. The Company considers its investment portfolio of marketable securities to be available-for-sale. Accordingly, these investments are recorded at fair value, which is based on quoted market prices. Unrealized gains and losses are reported as the accumulated other comprehensive items in stockholders’ equity. When the fair value is below the amortized cost of the asset, an estimate of expected credit losses is made. The credit-related impairment amount is recognized in net income (loss); the remaining impairment amount and unrealized gains are reported as a component of accumulated other comprehensive items in stockholders’ equity. Credit losses are recognized through the use of an allowance for credit losses account and subsequent improvements in expected credit losses are recognized as a reversal of an amount in the allowance for credit losses account. If the Company has the intent to sell the security or it is more likely than not that the Company will be required to sell the security prior to recovery of its amortized cost basis, then the allowance for the credit loss is written-off and the excess of the amortized cost basis of the asset over its fair value is recorded in the consolidated statements of operations and comprehensive loss. Regardless of the Company’s intent to sell a security, it performs additional analysis on all securities with unrealized losses to evaluate losses associated with the creditworthiness of the security. Credit losses are identified where the Company does not expect to receive cash flows sufficient to recover the amortized cost basis of a security. The Company adjusts the cost of available-for-sale debt securities for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion are included in interest income. The cost of securities sold is based on the specific identification method. The Company includes interest and dividends on securities classified as available-for-sale in interest income. Accounts Receivable The Company’s trade accounts receivable consist of amounts due from specialty distributors and specialty pharmacies that have been certified under a Risk Evaluation and Mitigation Strategy program in the U.S. related to sales of ZULRESSO and have standard payment terms that generally require payment within 30 to 90 days from the invoice date. The Company monitors the financial performance and creditworthiness of customers so that it can properly assess and respond to changes in their credit profiles. The Company makes judgments as to its ability to collect outstanding receivables and provides an allowance for bad debts against the trade account receivables, when appropriate. As of December 31, 2023 and 2022, trade accounts receivable were $1.4 million and $1.5 million, respectively, and are included in prepaid expenses and other current assets on the consolidated balance sheets. As of December 31, 2023, the Company has not provided any allowance for bad debts against the trade accounts receivable. Inventory Prior to the initial date that regulatory approval is received for a product candidate of the Company, costs related to the production of inventory are recorded as research and development expense on the Company’s consolidated statements of operations and comprehensive loss in the period incurred. Inventory is stated at the lower of cost or estimated net realizable value with cost determined on a first-in, first-out basis. Inventory costs may include purchases of raw materials, third-party contract manufacturing services, third-party packaging services, salary related expenses, overhead costs, and freight. Raw and intermediate materials that may be utilized for either research and development or commercial purposes, after approval of the product by the FDA, are classified as inventory. Amounts in inventory that are used for research and development purposes are charged to research and development expense when the product enters the research and development process and can no longer be used for commercial purposes and, therefore, does not have an “alternative future use” as defined in authoritative guidance. The Company performs an assessment of the recoverability of capitalized inventory during each reporting period and, if needed, writes down any excess and obsolete inventory to its estimated net realizable value in the period it is identified. If they occur, such impairment charges are recorded as a component of cost of revenues in the consolidated statements of operations and comprehensive loss. As of December 31, 2023 and 2022, inventory was $1.5 million and $1.7 million, respectively, and is included in prepaid expenses and other current assets on the consolidated balance sheets. Property and Equipment Property and equipment are recorded at cost and depreciated over their estimated useful lives using the straight-line method. Upon retirement or sale, the cost of assets disposed of and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is credited or charged to the Company’s consolidated statements of operations and comprehensive loss. Repairs and maintenance costs are expensed as incurred. Leases The Company determines if an arrangement is a lease at contract inception. Operating lease assets represent the Company’s right to use an underlying asset for the lease term and operating lease liabilities represent the Company’s obligation to make payments arising from the lease. Operating lease assets and liabilities are recognized at the commencement date of the lease based upon the present value of lease payments over the lease term. When determining the lease term, the Company includes options to extend or terminate the lease when it is reasonably certain that the Company will exercise those options. The Company uses the Company’s incremental borrowing rate when the implicit interest rate is not readily determinable based upon the information available at the commencement date of the lease in determining the present value of the lease payments and the implicit interest rate when readily determinable. The lease payments used to determine the Company’s operating lease assets may include lease incentives, stated rent increases and escalation clauses linked to rates of inflation, when determinable, and are recognized in the Company’s operating lease assets in the Company’s consolidated balance sheets. In addition, the Company’s contracts may contain lease and non-lease components. The Company combines lease and non-lease components, which are accounted for together as lease components. The Company’s operating leases are reflected in the right-of-use operating asset; operating lease liability, current portion; and operating lease liability, net of current portion in the Company’s consolidated balance sheets. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. Short-term leases, defined as leases that have a lease term of 12 months or less at the commencement date, are not recorded on the Company’s consolidated balance sheets and are recognized in the consolidated statements of operations and comprehensive loss on a straight-line basis over the term of the lease. Variable lease payments are the amounts owed by the Company to a lessor that are not fixed, such as reimbursement for common area maintenance and utilities costs for facility leases. Variable lease payments are expensed when incurred. Impairment of Long-Lived Assets Long-lived assets consist of property and equipment and lease right-of-use assets. Long-lived assets to be held and used are tested for recoverability whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends, and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long-lived asset group for recoverability, the Company compares forecasts of undiscounted cash flows expected to result from the use and eventual disposition of the long-lived asset group to its carrying value. The impairment loss would be based on the excess of the carrying value of the impaired asset over its fair value, determined based on discounted cash flows. To date, the Company has not recorded any impairment losses on long-lived assets. Cost of Revenues Cost of revenues includes direct and indirect costs related to the manufacturing and distribution of ZULRESSO, including third-party contract manufacturing costs, packaging services, freight, third-party royalties payable on the Company’s net product revenue of ZULRESSO and amortization of intangible assets associated with ZULRESSO. Cost of revenues also includes our proportionate share of ZURZUVAE manufacturing costs under the Biogen Collaboration Agreement, (for additional information, refer to Note 6, Collaboration Agreements). Cost of revenues may also include period costs related to certain inventory manufacturing services and inventory adjustment charges. Prior to receiving FDA approval of ZULRESSO in March 2019 and ZURZUVAE in August 2023, the Company manufactured inventory in preparation for launch. As a result, certain manufacturing costs associated with revenues were expensed prior to FDA approval and, therefore, a portion of such costs are not included in cost of revenues during the years ended December 31, 2023, 2022 and 2021. Research and Development Costs and Accruals Research and development expenses are comprised of costs incurred in performing research and development activities, including salaries and benefits, overhead costs, depreciation, contract services and other related costs. Research and development costs are expensed to operations as the related obligation is incurred. The Company has entered into various research and development contracts with research institutions and other companies both inside and outside of the U.S. These agreements are generally cancelable, and related costs are recorded as research and development expenses as incurred. The Company records accruals for estimated ongoing research and development costs. When billing terms under these contracts do not coincide with the timing of when the work is performed, the Company is required to make estimates of outstanding obligations to those third parties as of the end of the reporting period. Any accrual estimates are based on a number of factors, including the Company’s knowledge of the progress towards completion of the research and development activities, invoicing to date under the contracts, communication from the research institution or other companies of any actual costs incurred during the period that have not yet been invoiced, and the costs included in the contracts. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from the estimates made by the Company. The historical accrual estimates made by the Company have not been materially different from the actual costs. Stock-Based Compensation The Company recognizes stock-based compensation expense for grants under our stock incentive plans and employee stock purchase plan. The Company accounts for all stock-based awards granted to employees at their fair value and recognize compensation expense over the vesting period of the award. Determining the amount of stock-based compensation to be recorded requires the Company to develop estimates of fair values of stock options as of the grant date. The Company calculates the grant date fair values of stock options using the Black-Scholes valuation model, which requires the input of subjective assumptions, including but not limited to expected stock price volatility over the term of the awards, the expected term of stock options and the expected forfeiture rate. The fair value of restricted stock awards granted to employees is based upon the quoted closing market price per share on the date of grant. The Company has performance conditions included in certain of its performance restricted stock units that are based upon the achievement of pre-specified clinical development, regulatory, commercial and/or financial performance events. As the outcome of each event has inherent risk and uncertainties, and a positive outcome may not be known until the event is achieved, the Company begins to recognize the value of the performance-based restricted stock awards when the Company determines the achievement of each performance condition is deemed probable, a determination which requires significant judgment by management. At the probable date, the Company records estimated cumulative expense to date, with remaining expense amortized over the remaining service period until achievement has occurred. Treasury Stock The Company records treasury stock at cost. Treasury stock consists of shares of the Company’s common stock received from a then-employee as consideration for exercises of stock options. Basic and Diluted Net Loss Per Share Basic net loss per share is computed by dividing the net loss by the weighted average number of common shares outstanding for the period. For periods in which the Company has reported net losses, diluted net loss per share is the same as basic net loss per share, because dilutive common shares are not assumed to have been issued if their effect is antidilutive. The Company reported a net loss for the years ended December 31, 2023, 2022 and 2021. Concentration of Credit Risk and of Significant Suppliers Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash, cash equivalents and marketable securities. The Company maintains accounts for all cash and cash equivalents at accredited financial institutions, and consequently, the Company believes that such funds are subject to minimal credit risk. The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. The Company’s marketable securities, which primarily consist of U.S. government agency securities and treasuries, corporate bonds and commercial paper, potentially subject the Company to concentrations of credit risk. The Company has adopted an investment policy that limits the amounts the Company may invest in any one type of investment, defines allowable investments and requires all investments held by the Company to minimum credit rating standards, thereby reducing credit risk exposure. The Company has no significant off-balance sheet concentrations of credit risk, such as foreign currency exchange contracts, option contracts or other hedging arrangements. The Company is dependent on third-party manufacturers to supply products for research and development activities for its programs. The Company also relies on and expects to continue to rely on third-party manufacturers to supply it with active pharmaceutical ingredients (“API”) and formulated drugs; and to provide other services related to manufacturing activities for these programs. These programs could be adversely affected by a significant interruption in the supply of API and formulated drugs, or the interruption of manufacturing related services. Income Taxes The Company accounts for income taxes under the asset and liability method. Under this method, deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted rates in effect for the year in which these temporary differences are expected to be recovered or settled. Valuation allowances are provided if, based on the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company accounts for uncertain tax positions in accordance with the provisions of Accounting Standards Codification (“ASC”) Topic 740, “Income Taxes”. When uncertain tax positions exist, the Company recognizes the tax benefit of tax positions to the extent that the benefit will more likely than not be realized. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. The Company accrues for potential interest and penalties related to unrecognized tax benefits in income tax expense. Fair Value Measurements Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Financial assets and liabilities carried at fair value are classified and disclosed in one of the following three categories: Level 1 — Quoted market prices in active markets for identical assets or liabilities. Level 2 — Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The Company’s cash equivalents and marketable securities at December 31, 2023 and 2022 were carried at fair value, determined according to the fair value hierarchy; see Note 3, Fair Value Measurements. The carrying amounts reflected in the consolidated balance sheets for the collaboration receivable – related party, accounts payable and accrued expenses approximate their fair values due to their short-term maturities at December 31, 2023 and 2022, respectively. Segment Data The Company manages its operations as a single segment for the purposes of assessing performance and making operating decisions. The singular focus of the Company is to pioneer solutions to deliver life-changing brain health medicines, so every person can thrive. Comprehensive Income (Loss) Comprehensive loss includes net loss and other changes in stockholders’ equity that result from transactions and economic events other than those with stockholders. The Company’s only element of other comprehensive income (loss) is unrealized gains and losses on marketable securities that are considered to be available-for-sale. Revenue Recognition Under ASC Topic 606, Revenue from Contracts with Customers (“Topic 606”), an entity recognizes revenue when or as performance obligations are satisfied by transferring control of promised goods or services to a customer, in an amount that reflects the consideration that the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of Topic 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price, including variable consideration, if any; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. Arrangements that include rights to additional goods or services that are exercisable at a customer’s discretion are generally considered options. The Company assesses if these options provide a material right to the customer and if so, they are considered performance obligations. The exercise of a material right may be accounted for as a contract modification or as a continuation of the contract for accounting purposes. Topic 606 applies to all contracts with customers, except for contracts that are within the scope of other standards, such as collaboration arrangements. For contracts determined to be within the scope of Topic 606, the Company assesses whether the goods or services promised within each contract are distinct to identify those that are performance obligations. This assessment involves subjective determinations and requires management to make judgments about the individual promised goods or services and whether such are separable from the other aspects of the contractual relationship. Promised goods and services are considered distinct provided that: (i) the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer and (ii) the entity’s promise to transfer the good or service to the customer is separately identifiable from other promises in the contract. The Company allocates the transaction price (the amount of consideration it expects to be entitled to from a customer in exchange for the promised goods or services) to each performance obligation and recognizes the associated revenue when (or as) each performance obligation is satisfied. The Company’s estimate of the transaction price for each contract includes all variable consideration to which the Company expects to be entitled. Product Revenue, Net The Company generates product revenue from the sale of ZULRESSO to a limited number of specialty distributors and specialty pharmacy providers. The Company recognizes product revenue, net of variable consideration related to certain allowances and accruals that are determined using the expected value method, in its consolidated financial statements at the point in time when control transfers to the customer, which is typically when the product has been delivered to the customer’s location. The amount included in the transaction price is constrained to the amount for which it is probable that a significant reversal of cumulative revenue recognized will not occur. The Company’s only performance obligation identified for ZULRESSO is to deliver the product to the location specified by the customer’s order. The Company records shipping and handling costs associated with delivery of product to its customers within selling, general and administrative expenses on its consolidated statements of operations and comprehensive loss. The Company expenses incremental costs of obtaining a contract as incurred if the expected amortization period of the asset would be less than one year. If the Company were to incur incremental costs with an amortization period greater than a year, such costs would be capitalized as contract assets, as they are expected to be recovered, and would be expensed by amortizing on a systematic basis that is consistent with the transfer to the customer of the goods or services to which the asset relates. The Company did not have any contract assets (unbilled receivables) at December 31, 2023, as customer invoicing generally occurs before or at the time of revenue recognition. The Company did not have any contract liabilities at December 31, 2023, as the Company did not receive any payments in advance of satisfying its performance obligations to its customers. Amounts billed or invoiced that are considered trade accounts receivable are included in prepaid expenses and other current assets on the consolidated balance sheets. As of December 31, 2023 and 2022, the Company had not provided any allowance for bad debts against the trade accounts receivable, and the amount of trade accounts receivable was not significant. The Company records reserves, based on contractual terms, for the following components of variable consideration related to product sold during the reporting period, as well as its estimate of product that remains in the distribution channel inventory of its customers at the end of the reporting period. On a quarterly basis, the Company updates its estimates, if necessary, and records any material adjustments in the period they are identified. Chargebacks: The Company estimates chargebacks from its customers who directly purchase the product from the Company for discounts resulting from contractual commitments to sell products to eligible healthcare settings at prices lower than the list prices charged to its customers. Customers charge the Company for the difference between what they pay to the Company for the product and the selling price to the eligible healthcare settings. Reserves for chargebacks consist of credits that the Company expects to issue for units that remain in the distribution channel inventories at the end of each reporting period that the Company expects will be sold to eligible healthcare settings, and chargebacks that customers have claimed, but for which the Company has not yet issued a credit. Government Rebates: The Company is subject to discount obligations under government programs, including Medicaid. The Company records reserves for rebates in the same period the related product revenue is recognized, resulting in a reduction of ZULRESSO product revenue and a current liability that is included in accrued expenses on its consolidated balance sheets. The Company’s liability for these rebates consists of invoices received for claims from prior quarters that have not been paid or for which an invoice has not yet been received, estimates of claims for the current quarter, and estimates of future claims that will be made for product that has been recognized as revenue, but which remains in the distribution channel at the end of each reporting period. Trade Discounts and Allowances: The Company generally provides customary invoice discounts on ZULRESSO sales to its customers for prompt payment and the Company pays fees for sales order management, data, and distribution services. The Company estimates its customers will earn these discounts and fees and deducts these discounts and fees in full from gross ZULRESSO revenue and accounts receivable at the time the Company recognizes the related revenue. Financial Assistance: The Company provides voluntary financial assistance programs to patients with commercial insurance that have coverage and reside in states that allow financial assistance. The Company estimates the financial assistance amounts for ZULRESSO and records any such amounts within accrued expenses on its consolidated balance sheets. The calculation of the accrual for financial assistance is based on an estimate of claims and the cost per claim that the Company expects to receive using demographics for patients who have registered and been approved for assistance. Any adjustments are recorded in the same period the related revenue is recognized, resulting in a reduction of product revenue and the establishment of a current liability, which is included as a component of accrued expenses on the consolidated balance sheets. Product Returns: Consistent with industry practice, the Company offers product return rights to customers for damaged, defective or expiring product, provided it is within a specified period around the product expiration date as set forth in the Company’s return goods policy. The Company estimates the amount of its product sales that may be returned by its customers and records this estimate as a reduction of revenue in the period the related product revenue is recognized, as well as a reserve within accrued expenses on the consolidated balance sheets. Product returns have been not significant to date and are not expected to be significant in the future. License, Milestone and Collaboration Revenue In assessing whether a promised good or service is distinct in the evaluation of a collaboration or license arrangement subject to Topic 606, the Company considers factors such as the research, manufacturing and commercialization capabilities of the collaboration partner and the availability of the associated expertise in the general marketplace. The Company also considers the intended benefit of the contract in assessing whether a promised good or service is separately identifiable from other promises in the contract. If a promised good or service is not distinct, the Company is required to combine that good or service with other promised goods or services until it identifies a bundle of goods or services that is distinct. The transaction price is then determined and allocated to the identified performance obligations in proportion to their standalone selling prices (“SSP”) on a relative SSP basis. SSP is determined at contract inception and is not updated to reflect changes between contract inception and when the performance obligations are satisfied. Determining the SSP for performance obligations requires significant judgment. In developing the SSP for a performance obligation, the Company considers applicable market conditions and relevant entity-specific factors, including factors that were contemplated in negotiating the agreement with the customer and estimated costs. In certain circumstances, the Company may apply the residual method to determine the SSP of a good or service if the standalone selling price is considered highly variable or uncertain. The Company validates the SSP for performance obligations by evaluating whether changes in the key assumptions used to determine the SSP will have a significant effect on the allocation of arrangement consideration between multiple performance obligations. If the consideration promised in a contract includes a variable amount, the Company estimates the amount of consideration to which it will be entitled in exchange for transferring the promised goods or services to a customer. The Company determines the amount of variable consideration by using the expected value method or the most likely amount method. The Company includes the unconstrained amount of estimated variable consideration in the transaction price. The amount included in the transaction price is constrained to the amount for which it is probable that a significant reversal of cumulative revenue recognized will not occur. At the end of each subsequent reporting period, the Company re-evaluates the estimated variable consideration included in the transaction price and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis in the period of adjustment. If an arrangement includes development and regulatory milestone payments, the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s control or the licensee’s control, such as regulatory approvals, are generally not considered probable of being achieved until those approvals are received. In determining the transaction price, the Company adjusts consideration for the effects of the time value of money if the timing of payments provides the Company with a significant benefit of financing. The Company does not assess whether a contract has a significant financing component if the expectation at contract inception is such that the period between payment by the licensees and the transfer of the promised goods or services to the licensees will be one year or less. The Company assessed its arrangements with Shionogi & Co., Ltd. (“Shionogi”) and Biogen and concluded that a significant financing component does not exist for either arrangement. For arrangements with licenses of intellectual property that include sales-based royalties or milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties or milestone payments relate, the Company recognizes royalty revenue and sales-based milestones at the later of (i) when the related sales occur, or (ii) when the performance obligation to which the royalty or milestone payment has been allocated has been satisfied. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) each performance obligation is satisfied at a point in time or over time, and if over time this is based on the use of an output or input method. Revenue from the Company’s collaboration agreement with Shionogi has come from initial, upfront consideration upon execution of the agreement and for the supply of drug product for Shionogi’s clinical trials. Revenue from the Company’s collaboration agreement with Biogen has come from initial, upfront consideration related to the execution of the Biogen Collaboration Agreement, milestone payments and the Company’s share of ZURZUVAE revenues under the elements of the arrangement accounted for under ASC Topic 808. For additional information, see the Collaborative Arrangements section below and refer to Note 6, Collaboration Agreements. Collaborative Arrangements The Company analyzes its collaboration arrangements to assess whether such arrangements involve joint operating activities performed by parties that are both active participants in the activities and exposed to significant risks and rewards dependent on the commercial success of such activities and therefore within the scope of ASC Topic 808, Collaborative Arrangements (“Topic 808”). This assessment is performed throughout the life of the arrangement based on changes in the responsibilities of all parties in the arrangement. For collaboration arrangements within the scope of Topic 808 that contain multiple elements, the Company first determines which elements of the collaboration are deemed to be within the scope of Topic 808 and which elements of the collaboration are more reflective of a vendor-customer relationship and therefore within the scope of Topic 606. For elements of collaboration arrangements that are accounted for pursuant to Topic 808, an appropriate recognition method is determined and applied consistently, either by analogy to authoritative accounting literature or by applying a reasonable and rational policy election. For those elements of the arrangement that are accounted for pursuant to Topic 606, the Company applies the five-step model described above and presents the arrangement as license and milestone revenue or other collaboration revenue in the consolidated statements of operations and comprehensive loss. For collaboration arrangements that are within the scope of Topic 808, the Company evaluates the income statement classification for presentation of amounts due from or owed to other participants associated with multiple activities in a collaboration arrangement based on the nature of each separate activity. Payments or reimbursements that are the result of a collaborative relationship instead of a vendor-customer relationship are recorded as an increase to collaboration revenue, an increase to or reduction of cost of revenues, research and development expense or selling, general and administrative expense, depending on the nature of the activity. For additional information relating to the accounting for the co-commercialization of ZURZUVAE in the U.S. with Biogen under Topic 808, refer to Note 6, Collaboration Agreements. Recently Issued Accounting Pronouncements Other accounting standards that have been issued or proposed by the Financial Accounting Standards Board (“FASB”) or other standards-setting bodies that do not require adoption until a future date are not expected to have a material impact on the Company’s consolidated financial statements upon adoption.

Summary of Significant Accounting Policies (Policies)	12 Months Ended
Summary of Significant Accounting Policies (Policies)	Dec. 31, 2023
Accounting Policies [Abstract]
Risks and Uncertainties	Risks and Uncertainties The Company is subject to risks and uncertainties common to companies in the biopharmaceutical industry, including, but not limited to, the risks associated with developing product candidates at each stage of non-clinical and clinical development; the challenges associated with gaining regulatory approval of such product candidates; the risks associated with the marketing and sale of pharmaceutical products; the potential for development by third parties of new technological innovations that may compete with the Company’s products and product candidates; the dependence on key personnel; the challenges of protecting proprietary technology; the need to comply with government regulations; the high costs of drug development; the uncertainty of being able to secure additional capital when needed to fund operations; and the direct or indirect impacts of the macroeconomic environment and geopolitical events on its development activities, operations and financial condition. The product candidates developed by the Company require approvals from the FDA or foreign regulatory agencies prior to commercial sales. There can be no assurance that the current and future product candidates of the Company will receive, or that the Company’s current products, ZULRESSO and ZURZUVAE, will maintain, the necessary approvals. If the Company fails to successfully complete clinical development and generate results sufficient to file for regulatory approval or is denied approval or approval is delayed for any of its product candidates, such occurrences may have a material adverse impact on the Company’s business and its financial condition. The Company is also subject to additional risks and uncertainties arising from changes to the macroeconomic environment and geopolitical events. U.S. and global financial markets have experienced volatility and disruption due to macroeconomic and geopolitical events such as rising inflation, the risk of a recession and ongoing conflicts in other countries. In addition, if equity and credit markets deteriorate, including as a result of past and potential future bank failures, it may make any future debt or equity financing more difficult to obtain on favorable terms, and potentially more dilutive to its existing stockholders. The Company cannot predict at this time to what extent it and its collaborators, employees, suppliers, contract manufacturers and/or vendors could potentially be negatively impacted by these events.
Going Concern	Going Concern Under Accounting Standards Update (“ASU”) No. 2014-15, Presentation of Financial Statements—Going Concern (Subtopic 205-40), the Company has the responsibility to evaluate whether conditions and/or events raise substantial doubt about its ability to meet its future financial obligations as they become due within one year after the date that the financial statements are issued. The Company has incurred losses and negative cash flows from operations in each year since its inception, except for net income of $606.1 million for the year ended December 31, 2020, reflecting revenue recognized under a collaboration and license agreement with Biogen (the “Biogen Collaboration Agreement”). As of December 31, 2023, the Company had an accumulated deficit of $2.6 billion. Until such time, if ever, as the Company can generate substantial product revenue and/or collaboration revenue and achieve sustained profitability, the Company expects to finance its cash needs through a combination of equity offerings, debt financings, collaborations, strategic alliances, licensing arrangements and other sources of funding. If the Company is unable to raise additional funds through equity or debt financings or other sources of funding when needed, the Company may be required to delay, limit, reduce or terminate product development or future commercialization efforts or grant rights to develop and market products or product candidates that the Company would otherwise prefer to develop and market itself. The Company expects that, based on its current operating plans, the Company’s existing cash, cash equivalents and marketable securities will be sufficient to fund its currently planned operations for at least the next 12 months from the filing date of this Annual Report. At some point after that time, the Company anticipates it will require additional financing to fund its future operations. Even if the Company believes it has sufficient funds for its current or future operating plans, the Company may seek to raise additional capital if market conditions are favorable or in light of other strategic considerations.
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements include those of the Company and its subsidiaries after elimination of all intercompany accounts and transactions. The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the U.S. (“GAAP”).
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. Intercompany accounts and transactions have been eliminated.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period.
Cash Equivalents	Cash Equivalents The Company considers all highly liquid investments with an original maturity of 90 days or less to be cash equivalents. As of December 31, 2023, cash equivalents were comprised of money market funds and U.S. government securities. As of December 31, 2022, cash equivalents were comprised of money market funds.
Marketable Securities	Marketable Securities Marketable securities consist of investments with original maturities greater than 90 days. The Company has classified its investments with maturities beyond one year as short-term, based on their highly liquid nature and because such marketable securities represent the investment of cash that is available for current operations. The Company considers its investment portfolio of marketable securities to be available-for-sale. Accordingly, these investments are recorded at fair value, which is based on quoted market prices. Unrealized gains and losses are reported as the accumulated other comprehensive items in stockholders’ equity. When the fair value is below the amortized cost of the asset, an estimate of expected credit losses is made. The credit-related impairment amount is recognized in net income (loss); the remaining impairment amount and unrealized gains are reported as a component of accumulated other comprehensive items in stockholders’ equity. Credit losses are recognized through the use of an allowance for credit losses account and subsequent improvements in expected credit losses are recognized as a reversal of an amount in the allowance for credit losses account. If the Company has the intent to sell the security or it is more likely than not that the Company will be required to sell the security prior to recovery of its amortized cost basis, then the allowance for the credit loss is written-off and the excess of the amortized cost basis of the asset over its fair value is recorded in the consolidated statements of operations and comprehensive loss. Regardless of the Company’s intent to sell a security, it performs additional analysis on all securities with unrealized losses to evaluate losses associated with the creditworthiness of the security. Credit losses are identified where the Company does not expect to receive cash flows sufficient to recover the amortized cost basis of a security. The Company adjusts the cost of available-for-sale debt securities for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion are included in interest income. The cost of securities sold is based on the specific identification method. The Company includes interest and dividends on securities classified as available-for-sale in interest income.
Accounts Receivable	Accounts Receivable The Company’s trade accounts receivable consist of amounts due from specialty distributors and specialty pharmacies that have been certified under a Risk Evaluation and Mitigation Strategy program in the U.S. related to sales of ZULRESSO and have standard payment terms that generally require payment within 30 to 90 days from the invoice date. The Company monitors the financial performance and creditworthiness of customers so that it can properly assess and respond to changes in their credit profiles. The Company makes judgments as to its ability to collect outstanding receivables and provides an allowance for bad debts against the trade account receivables, when appropriate. As of December 31, 2023 and 2022, trade accounts receivable were $1.4 million and $1.5 million, respectively, and are included in prepaid expenses and other current assets on the consolidated balance sheets. As of December 31, 2023, the Company has not provided any allowance for bad debts against the trade accounts receivable.
Inventory	Inventory Prior to the initial date that regulatory approval is received for a product candidate of the Company, costs related to the production of inventory are recorded as research and development expense on the Company’s consolidated statements of operations and comprehensive loss in the period incurred. Inventory is stated at the lower of cost or estimated net realizable value with cost determined on a first-in, first-out basis. Inventory costs may include purchases of raw materials, third-party contract manufacturing services, third-party packaging services, salary related expenses, overhead costs, and freight. Raw and intermediate materials that may be utilized for either research and development or commercial purposes, after approval of the product by the FDA, are classified as inventory. Amounts in inventory that are used for research and development purposes are charged to research and development expense when the product enters the research and development process and can no longer be used for commercial purposes and, therefore, does not have an “alternative future use” as defined in authoritative guidance. The Company performs an assessment of the recoverability of capitalized inventory during each reporting period and, if needed, writes down any excess and obsolete inventory to its estimated net realizable value in the period it is identified. If they occur, such impairment charges are recorded as a component of cost of revenues in the consolidated statements of operations and comprehensive loss. As of December 31, 2023 and 2022, inventory was $1.5 million and $1.7 million, respectively, and is included in prepaid expenses and other current assets on the consolidated balance sheets.
Property and Equipment	Property and Equipment Property and equipment are recorded at cost and depreciated over their estimated useful lives using the straight-line method. Upon retirement or sale, the cost of assets disposed of and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is credited or charged to the Company’s consolidated statements of operations and comprehensive loss. Repairs and maintenance costs are expensed as incurred.
Leases	Leases The Company determines if an arrangement is a lease at contract inception. Operating lease assets represent the Company’s right to use an underlying asset for the lease term and operating lease liabilities represent the Company’s obligation to make payments arising from the lease. Operating lease assets and liabilities are recognized at the commencement date of the lease based upon the present value of lease payments over the lease term. When determining the lease term, the Company includes options to extend or terminate the lease when it is reasonably certain that the Company will exercise those options. The Company uses the Company’s incremental borrowing rate when the implicit interest rate is not readily determinable based upon the information available at the commencement date of the lease in determining the present value of the lease payments and the implicit interest rate when readily determinable. The lease payments used to determine the Company’s operating lease assets may include lease incentives, stated rent increases and escalation clauses linked to rates of inflation, when determinable, and are recognized in the Company’s operating lease assets in the Company’s consolidated balance sheets. In addition, the Company’s contracts may contain lease and non-lease components. The Company combines lease and non-lease components, which are accounted for together as lease components. The Company’s operating leases are reflected in the right-of-use operating asset; operating lease liability, current portion; and operating lease liability, net of current portion in the Company’s consolidated balance sheets. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. Short-term leases, defined as leases that have a lease term of 12 months or less at the commencement date, are not recorded on the Company’s consolidated balance sheets and are recognized in the consolidated statements of operations and comprehensive loss on a straight-line basis over the term of the lease. Variable lease payments are the amounts owed by the Company to a lessor that are not fixed, such as reimbursement for common area maintenance and utilities costs for facility leases. Variable lease payments are expensed when incurred.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets Long-lived assets consist of property and equipment and lease right-of-use assets. Long-lived assets to be held and used are tested for recoverability whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends, and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long-lived asset group for recoverability, the Company compares forecasts of undiscounted cash flows expected to result from the use and eventual disposition of the long-lived asset group to its carrying value. The impairment loss would be based on the excess of the carrying value of the impaired asset over its fair value, determined based on discounted cash flows. To date, the Company has not recorded any impairment losses on long-lived assets.
Cost of Revenues	Cost of Revenues Cost of revenues includes direct and indirect costs related to the manufacturing and distribution of ZULRESSO, including third-party contract manufacturing costs, packaging services, freight, third-party royalties payable on the Company’s net product revenue of ZULRESSO and amortization of intangible assets associated with ZULRESSO. Cost of revenues also includes our proportionate share of ZURZUVAE manufacturing costs under the Biogen Collaboration Agreement, (for additional information, refer to Note 6, Collaboration Agreements). Cost of revenues may also include period costs related to certain inventory manufacturing services and inventory adjustment charges. Prior to receiving FDA approval of ZULRESSO in March 2019 and ZURZUVAE in August 2023, the Company manufactured inventory in preparation for launch. As a result, certain manufacturing costs associated with revenues were expensed prior to FDA approval and, therefore, a portion of such costs are not included in cost of revenues during the years ended December 31, 2023, 2022 and 2021.
Research and Development Costs and Accruals	Research and Development Costs and Accruals Research and development expenses are comprised of costs incurred in performing research and development activities, including salaries and benefits, overhead costs, depreciation, contract services and other related costs. Research and development costs are expensed to operations as the related obligation is incurred. The Company has entered into various research and development contracts with research institutions and other companies both inside and outside of the U.S. These agreements are generally cancelable, and related costs are recorded as research and development expenses as incurred. The Company records accruals for estimated ongoing research and development costs. When billing terms under these contracts do not coincide with the timing of when the work is performed, the Company is required to make estimates of outstanding obligations to those third parties as of the end of the reporting period. Any accrual estimates are based on a number of factors, including the Company’s knowledge of the progress towards completion of the research and development activities, invoicing to date under the contracts, communication from the research institution or other companies of any actual costs incurred during the period that have not yet been invoiced, and the costs included in the contracts. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from the estimates made by the Company. The historical accrual estimates made by the Company have not been materially different from the actual costs.
Stock-Based Compensation	Stock-Based Compensation The Company recognizes stock-based compensation expense for grants under our stock incentive plans and employee stock purchase plan. The Company accounts for all stock-based awards granted to employees at their fair value and recognize compensation expense over the vesting period of the award. Determining the amount of stock-based compensation to be recorded requires the Company to develop estimates of fair values of stock options as of the grant date. The Company calculates the grant date fair values of stock options using the Black-Scholes valuation model, which requires the input of subjective assumptions, including but not limited to expected stock price volatility over the term of the awards, the expected term of stock options and the expected forfeiture rate. The fair value of restricted stock awards granted to employees is based upon the quoted closing market price per share on the date of grant. The Company has performance conditions included in certain of its performance restricted stock units that are based upon the achievement of pre-specified clinical development, regulatory, commercial and/or financial performance events. As the outcome of each event has inherent risk and uncertainties, and a positive outcome may not be known until the event is achieved, the Company begins to recognize the value of the performance-based restricted stock awards when the Company determines the achievement of each performance condition is deemed probable, a determination which requires significant judgment by management. At the probable date, the Company records estimated cumulative expense to date, with remaining expense amortized over the remaining service period until achievement has occurred.
Treasury Stock	Treasury Stock The Company records treasury stock at cost. Treasury stock consists of shares of the Company’s common stock received from a then-employee as consideration for exercises of stock options.
Basic and Diluted Net Loss Per Share	Basic and Diluted Net Loss Per Share Basic net loss per share is computed by dividing the net loss by the weighted average number of common shares outstanding for the period. For periods in which the Company has reported net losses, diluted net loss per share is the same as basic net loss per share, because dilutive common shares are not assumed to have been issued if their effect is antidilutive. The Company reported a net loss for the years ended December 31, 2023, 2022 and 2021.
Concentration of Credit Risk and of Significant Suppliers	Concentration of Credit Risk and of Significant Suppliers Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash, cash equivalents and marketable securities. The Company maintains accounts for all cash and cash equivalents at accredited financial institutions, and consequently, the Company believes that such funds are subject to minimal credit risk. The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. The Company’s marketable securities, which primarily consist of U.S. government agency securities and treasuries, corporate bonds and commercial paper, potentially subject the Company to concentrations of credit risk. The Company has adopted an investment policy that limits the amounts the Company may invest in any one type of investment, defines allowable investments and requires all investments held by the Company to minimum credit rating standards, thereby reducing credit risk exposure. The Company has no significant off-balance sheet concentrations of credit risk, such as foreign currency exchange contracts, option contracts or other hedging arrangements. The Company is dependent on third-party manufacturers to supply products for research and development activities for its programs. The Company also relies on and expects to continue to rely on third-party manufacturers to supply it with active pharmaceutical ingredients (“API”) and formulated drugs; and to provide other services related to manufacturing activities for these programs. These programs could be adversely affected by a significant interruption in the supply of API and formulated drugs, or the interruption of manufacturing related services.
Income Taxes	Income Taxes The Company accounts for income taxes under the asset and liability method. Under this method, deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted rates in effect for the year in which these temporary differences are expected to be recovered or settled. Valuation allowances are provided if, based on the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company accounts for uncertain tax positions in accordance with the provisions of Accounting Standards Codification (“ASC”) Topic 740, “Income Taxes”. When uncertain tax positions exist, the Company recognizes the tax benefit of tax positions to the extent that the benefit will more likely than not be realized. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. The Company accrues for potential interest and penalties related to unrecognized tax benefits in income tax expense.
Fair Value Measurements	Fair Value Measurements Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Financial assets and liabilities carried at fair value are classified and disclosed in one of the following three categories: Level 1 — Quoted market prices in active markets for identical assets or liabilities. Level 2 — Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The Company’s cash equivalents and marketable securities at December 31, 2023 and 2022 were carried at fair value, determined according to the fair value hierarchy; see Note 3, Fair Value Measurements. The carrying amounts reflected in the consolidated balance sheets for the collaboration receivable – related party, accounts payable and accrued expenses approximate their fair values due to their short-term maturities at December 31, 2023 and 2022, respectively.
Segment Data	Segment Data The Company manages its operations as a single segment for the purposes of assessing performance and making operating decisions. The singular focus of the Company is to pioneer solutions to deliver life-changing brain health medicines, so every person can thrive.
Comprehensive Income (Loss)	Comprehensive Income (Loss) Comprehensive loss includes net loss and other changes in stockholders’ equity that result from transactions and economic events other than those with stockholders. The Company’s only element of other comprehensive income (loss) is unrealized gains and losses on marketable securities that are considered to be available-for-sale.
Revenue Recognition	Revenue Recognition Under ASC Topic 606, Revenue from Contracts with Customers (“Topic 606”), an entity recognizes revenue when or as performance obligations are satisfied by transferring control of promised goods or services to a customer, in an amount that reflects the consideration that the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of Topic 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price, including variable consideration, if any; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. Arrangements that include rights to additional goods or services that are exercisable at a customer’s discretion are generally considered options. The Company assesses if these options provide a material right to the customer and if so, they are considered performance obligations. The exercise of a material right may be accounted for as a contract modification or as a continuation of the contract for accounting purposes. Topic 606 applies to all contracts with customers, except for contracts that are within the scope of other standards, such as collaboration arrangements. For contracts determined to be within the scope of Topic 606, the Company assesses whether the goods or services promised within each contract are distinct to identify those that are performance obligations. This assessment involves subjective determinations and requires management to make judgments about the individual promised goods or services and whether such are separable from the other aspects of the contractual relationship. Promised goods and services are considered distinct provided that: (i) the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer and (ii) the entity’s promise to transfer the good or service to the customer is separately identifiable from other promises in the contract. The Company allocates the transaction price (the amount of consideration it expects to be entitled to from a customer in exchange for the promised goods or services) to each performance obligation and recognizes the associated revenue when (or as) each performance obligation is satisfied. The Company’s estimate of the transaction price for each contract includes all variable consideration to which the Company expects to be entitled. Product Revenue, Net The Company generates product revenue from the sale of ZULRESSO to a limited number of specialty distributors and specialty pharmacy providers. The Company recognizes product revenue, net of variable consideration related to certain allowances and accruals that are determined using the expected value method, in its consolidated financial statements at the point in time when control transfers to the customer, which is typically when the product has been delivered to the customer’s location. The amount included in the transaction price is constrained to the amount for which it is probable that a significant reversal of cumulative revenue recognized will not occur. The Company’s only performance obligation identified for ZULRESSO is to deliver the product to the location specified by the customer’s order. The Company records shipping and handling costs associated with delivery of product to its customers within selling, general and administrative expenses on its consolidated statements of operations and comprehensive loss. The Company expenses incremental costs of obtaining a contract as incurred if the expected amortization period of the asset would be less than one year. If the Company were to incur incremental costs with an amortization period greater than a year, such costs would be capitalized as contract assets, as they are expected to be recovered, and would be expensed by amortizing on a systematic basis that is consistent with the transfer to the customer of the goods or services to which the asset relates. The Company did not have any contract assets (unbilled receivables) at December 31, 2023, as customer invoicing generally occurs before or at the time of revenue recognition. The Company did not have any contract liabilities at December 31, 2023, as the Company did not receive any payments in advance of satisfying its performance obligations to its customers. Amounts billed or invoiced that are considered trade accounts receivable are included in prepaid expenses and other current assets on the consolidated balance sheets. As of December 31, 2023 and 2022, the Company had not provided any allowance for bad debts against the trade accounts receivable, and the amount of trade accounts receivable was not significant. The Company records reserves, based on contractual terms, for the following components of variable consideration related to product sold during the reporting period, as well as its estimate of product that remains in the distribution channel inventory of its customers at the end of the reporting period. On a quarterly basis, the Company updates its estimates, if necessary, and records any material adjustments in the period they are identified. Chargebacks: The Company estimates chargebacks from its customers who directly purchase the product from the Company for discounts resulting from contractual commitments to sell products to eligible healthcare settings at prices lower than the list prices charged to its customers. Customers charge the Company for the difference between what they pay to the Company for the product and the selling price to the eligible healthcare settings. Reserves for chargebacks consist of credits that the Company expects to issue for units that remain in the distribution channel inventories at the end of each reporting period that the Company expects will be sold to eligible healthcare settings, and chargebacks that customers have claimed, but for which the Company has not yet issued a credit. Government Rebates: The Company is subject to discount obligations under government programs, including Medicaid. The Company records reserves for rebates in the same period the related product revenue is recognized, resulting in a reduction of ZULRESSO product revenue and a current liability that is included in accrued expenses on its consolidated balance sheets. The Company’s liability for these rebates consists of invoices received for claims from prior quarters that have not been paid or for which an invoice has not yet been received, estimates of claims for the current quarter, and estimates of future claims that will be made for product that has been recognized as revenue, but which remains in the distribution channel at the end of each reporting period. Trade Discounts and Allowances: The Company generally provides customary invoice discounts on ZULRESSO sales to its customers for prompt payment and the Company pays fees for sales order management, data, and distribution services. The Company estimates its customers will earn these discounts and fees and deducts these discounts and fees in full from gross ZULRESSO revenue and accounts receivable at the time the Company recognizes the related revenue. Financial Assistance: The Company provides voluntary financial assistance programs to patients with commercial insurance that have coverage and reside in states that allow financial assistance. The Company estimates the financial assistance amounts for ZULRESSO and records any such amounts within accrued expenses on its consolidated balance sheets. The calculation of the accrual for financial assistance is based on an estimate of claims and the cost per claim that the Company expects to receive using demographics for patients who have registered and been approved for assistance. Any adjustments are recorded in the same period the related revenue is recognized, resulting in a reduction of product revenue and the establishment of a current liability, which is included as a component of accrued expenses on the consolidated balance sheets. Product Returns: Consistent with industry practice, the Company offers product return rights to customers for damaged, defective or expiring product, provided it is within a specified period around the product expiration date as set forth in the Company’s return goods policy. The Company estimates the amount of its product sales that may be returned by its customers and records this estimate as a reduction of revenue in the period the related product revenue is recognized, as well as a reserve within accrued expenses on the consolidated balance sheets. Product returns have been not significant to date and are not expected to be significant in the future. License, Milestone and Collaboration Revenue In assessing whether a promised good or service is distinct in the evaluation of a collaboration or license arrangement subject to Topic 606, the Company considers factors such as the research, manufacturing and commercialization capabilities of the collaboration partner and the availability of the associated expertise in the general marketplace. The Company also considers the intended benefit of the contract in assessing whether a promised good or service is separately identifiable from other promises in the contract. If a promised good or service is not distinct, the Company is required to combine that good or service with other promised goods or services until it identifies a bundle of goods or services that is distinct. The transaction price is then determined and allocated to the identified performance obligations in proportion to their standalone selling prices (“SSP”) on a relative SSP basis. SSP is determined at contract inception and is not updated to reflect changes between contract inception and when the performance obligations are satisfied. Determining the SSP for performance obligations requires significant judgment. In developing the SSP for a performance obligation, the Company considers applicable market conditions and relevant entity-specific factors, including factors that were contemplated in negotiating the agreement with the customer and estimated costs. In certain circumstances, the Company may apply the residual method to determine the SSP of a good or service if the standalone selling price is considered highly variable or uncertain. The Company validates the SSP for performance obligations by evaluating whether changes in the key assumptions used to determine the SSP will have a significant effect on the allocation of arrangement consideration between multiple performance obligations. If the consideration promised in a contract includes a variable amount, the Company estimates the amount of consideration to which it will be entitled in exchange for transferring the promised goods or services to a customer. The Company determines the amount of variable consideration by using the expected value method or the most likely amount method. The Company includes the unconstrained amount of estimated variable consideration in the transaction price. The amount included in the transaction price is constrained to the amount for which it is probable that a significant reversal of cumulative revenue recognized will not occur. At the end of each subsequent reporting period, the Company re-evaluates the estimated variable consideration included in the transaction price and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis in the period of adjustment. If an arrangement includes development and regulatory milestone payments, the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s control or the licensee’s control, such as regulatory approvals, are generally not considered probable of being achieved until those approvals are received. In determining the transaction price, the Company adjusts consideration for the effects of the time value of money if the timing of payments provides the Company with a significant benefit of financing. The Company does not assess whether a contract has a significant financing component if the expectation at contract inception is such that the period between payment by the licensees and the transfer of the promised goods or services to the licensees will be one year or less. The Company assessed its arrangements with Shionogi & Co., Ltd. (“Shionogi”) and Biogen and concluded that a significant financing component does not exist for either arrangement. For arrangements with licenses of intellectual property that include sales-based royalties or milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties or milestone payments relate, the Company recognizes royalty revenue and sales-based milestones at the later of (i) when the related sales occur, or (ii) when the performance obligation to which the royalty or milestone payment has been allocated has been satisfied. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) each performance obligation is satisfied at a point in time or over time, and if over time this is based on the use of an output or input method. Revenue from the Company’s collaboration agreement with Shionogi has come from initial, upfront consideration upon execution of the agreement and for the supply of drug product for Shionogi’s clinical trials. Revenue from the Company’s collaboration agreement with Biogen has come from initial, upfront consideration related to the execution of the Biogen Collaboration Agreement, milestone payments and the Company’s share of ZURZUVAE revenues under the elements of the arrangement accounted for under ASC Topic 808. For additional information, see the Collaborative Arrangements section below and refer to Note 6, Collaboration Agreements.
Collaborative Arrangements	Collaborative Arrangements The Company analyzes its collaboration arrangements to assess whether such arrangements involve joint operating activities performed by parties that are both active participants in the activities and exposed to significant risks and rewards dependent on the commercial success of such activities and therefore within the scope of ASC Topic 808, Collaborative Arrangements (“Topic 808”). This assessment is performed throughout the life of the arrangement based on changes in the responsibilities of all parties in the arrangement. For collaboration arrangements within the scope of Topic 808 that contain multiple elements, the Company first determines which elements of the collaboration are deemed to be within the scope of Topic 808 and which elements of the collaboration are more reflective of a vendor-customer relationship and therefore within the scope of Topic 606. For elements of collaboration arrangements that are accounted for pursuant to Topic 808, an appropriate recognition method is determined and applied consistently, either by analogy to authoritative accounting literature or by applying a reasonable and rational policy election. For those elements of the arrangement that are accounted for pursuant to Topic 606, the Company applies the five-step model described above and presents the arrangement as license and milestone revenue or other collaboration revenue in the consolidated statements of operations and comprehensive loss. For collaboration arrangements that are within the scope of Topic 808, the Company evaluates the income statement classification for presentation of amounts due from or owed to other participants associated with multiple activities in a collaboration arrangement based on the nature of each separate activity. Payments or reimbursements that are the result of a collaborative relationship instead of a vendor-customer relationship are recorded as an increase to collaboration revenue, an increase to or reduction of cost of revenues, research and development expense or selling, general and administrative expense, depending on the nature of the activity. For additional information relating to the accounting for the co-commercialization of ZURZUVAE in the U.S. with Biogen under Topic 808, refer to Note 6, Collaboration Agreements.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements Other accounting standards that have been issued or proposed by the Financial Accounting Standards Board (“FASB”) or other standards-setting bodies that do not require adoption until a future date are not expected to have a material impact on the Company’s consolidated financial statements upon adoption.

Stock-Based Compensation - Summary of Activity Relating to Time Based and Performance Based Stock Options (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ending balance, Outstanding Shares	11,206,435
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, Outstanding Shares	7,788,350
Granted, Shares	964,253
Exercised, Shares	(65,940)
Forfeited, Shares	(568,622)
Ending balance, Outstanding Shares	8,118,041	7,788,350
Vested and expected to vest, Shares	7,389,812
Exercisable, Shares	6,116,989
Beginning balance, Outstanding Weighted Average Exercise Price	$ 77.95
Granted, Weighted Average Exercise Price	44.58
Exercised, Weighted Average Exercise Price	16.58
Forfeited, Weighted Average Exercise Price	56.00
Ending balance, Outstanding Weighted Average Exercise Price	76.02	$ 77.95
Vested and expected to vest, Weighted Average Exercise Price	76.55
Exercisable, Weighted Average Exercise Price	$ 81.94
Outstanding, Weighted Average Remaining Life	5 years 7 months 28 days	6 years 4 months 9 days
Vested and expected to vest, Weighted Average Remaining Life	5 years 5 months 19 days
Exercisable, Weighted Average Remaining Life	4 years 10 months 2 days
Outstanding, Aggregate Intrinsic Value	$ 475	$ 7,275
Vested and expected to vest, Aggregate Intrinsic Value	455
Exercisable, Aggregate Intrinsic Value	$ 403

Balance Sheet Components - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 1,393	$ 1,122	$ 4,182
Purchase commitment, cancelling excess amount committed	4,300
Research and Development Expense [Member]
Property, Plant and Equipment [Line Items]
Purchase commitment, cancelling excess amount committed	28,900
Research and Development Expense [Member] \| Biogen Collaboration Agreement [Member]
Property, Plant and Equipment [Line Items]
Reimbursement expense	$ 14,500
Computer Hardware and Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	3 years
Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	5 years

Income Taxes - Summary of Significant Components of Company's Net Deferred Tax Asset (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Net operating losses	$ 428,785	$ 347,880
Tax credits	133,602	118,393
Capitalized research and development expenses	110,690	66,849
Stock-based compensation	53,860	49,916
Accrued expenses	7,018	8,750
Depreciation and amortization	1,456	1,386
Lease liability	1,207	2,803
Right of use asset	(1,042)	(2,433)
Other	(382)	(258)
Total net deferred tax asset before valuation allowance	735,194	593,286
Valuation allowance	$ (735,194)	$ (593,286)

Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Gain (Loss) [Member]	Accumulated Deficit [Member]
Balances at Dec. 31, 2020	$ 2,072,334	$ 6	$ (400)	$ 3,109,807	$ 415	$ (1,037,494)
Balances, Shares at Dec. 31, 2020		58,308,411	3,033
Issuance of common stock from exercise of stock options, Amount	12,397			12,397
Issuance of common stock from exercise of stock options, Shares		307,378
Issuance of common stock under the employee stock purchase plan	2,761			2,761
Issuance of common stock under the employee stock purchase plan, Shares		46,759
Stock-based compensation expense	103,891			103,891
Vesting of restricted stock units, net of employee tax obligations	(1,385)			(1,385)
Vesting of restricted stock units, net of employee tax obligations, Shares		274,502
Change in unrealized loss on available-for-sale securities	(3,075)				(3,075)
Net Income (Loss)	(457,892)					(457,892)
Balances at Dec. 31, 2021	1,729,031	$ 6	$ (400)	3,227,471	(2,660)	(1,495,386)
Balances, Shares at Dec. 31, 2021		58,937,050	3,033
Issuance of common stock from exercise of stock options, Amount	1,037			1,037
Issuance of common stock from exercise of stock options, Shares		150,045
Issuance of common stock under the employee stock purchase plan	2,346			2,346
Issuance of common stock under the employee stock purchase plan, Shares		57,239
Stock-based compensation expense	60,558			60,558
Vesting of restricted stock units, net of employee tax obligations	(43)			(43)
Vesting of restricted stock units, net of employee tax obligations, Shares		364,791
Change in unrealized loss on available-for-sale securities	(7,546)				(7,546)
Net Income (Loss)	(532,784)					(532,784)
Balances at Dec. 31, 2022	1,252,599	$ 6	$ (400)	3,291,369	(10,206)	(2,028,170)
Balances, Shares at Dec. 31, 2022		59,509,125	3,033
Issuance of common stock from exercise of stock options, Amount	1,293			1,293
Issuance of common stock from exercise of stock options, Shares		72,090
Issuance of common stock under the employee stock purchase plan	6,519			6,519
Issuance of common stock under the employee stock purchase plan, Shares		164,043
Stock-based compensation expense	72,119			72,119
Vesting of restricted stock units, net of employee tax obligations	(903)			(903)
Vesting of restricted stock units, net of employee tax obligations, Shares		298,385
Change in unrealized loss on available-for-sale securities	9,392				9,392
Net Income (Loss)	(541,489)					(541,489)
Balances at Dec. 31, 2023	$ 799,530	$ 6	$ (400)	$ 3,370,397	$ (814)	$ (2,569,659)
Balances, Shares at Dec. 31, 2023		60,043,643	3,033

Nature of the Business - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2023	Dec. 31, 2022
Nature Of Business [Line Items]
Net income from up-front	$ 606,100
Accumulated deficit		$ 2,569,659	$ 2,028,170
Redeemable Convertible Preferred Stock [Member] \| Convertible Notes [Member] \| Initial Public Offering [Member]
Nature Of Business [Line Items]
Accumulated deficit		$ 2,600,000

- Definition

Amount of accumulated undistributed earnings (deficit).

+ References + Details

Balance Sheet Components - Summary of Accrued Expenses (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Accrued research and development costs	$ 26,040	$ 32,565
Restructuring	10,589
Employee-related	21,339	29,372
Professional services	8,589	10,172
Other	707	557
Total accrued expenses	$ 67,264	$ 72,666

Leases, Commitments and Contingencies - University of California License Agreements - Additional Information (Detail) - University of California License Agreements [Member] - USD ($)		1 Months Ended	12 Months Ended				100 Months Ended
	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2015	Dec. 31, 2023
Commitments And Contingencies [Line Items]
Upfront payment		$ 50,000
Annual license maintenance fee						$ 15,000
Milestone payments			$ 0	$ 0	$ 0
After The Effective Date [Member]
Commitments And Contingencies [Line Items]
Licenses Expiration period, maximum	27 years
After The First Sale [Member]
Commitments And Contingencies [Line Items]
Licenses Expiration period, maximum	15 years
Clinical Development [Member]
Commitments And Contingencies [Line Items]
Milestone payments	$ 100,000
Milestone outstanding	$ 0
Clinical Development [Member] \| Maximum [Member]
Commitments And Contingencies [Line Items]
Percentage of net sales paid as royalties	1.00%
Regulatory Milestones [Member] \| Maximum [Member]
Commitments And Contingencies [Line Items]
Expected milestone payments		700,000
Sales Milestones [Member] \| Maximum [Member]
Commitments And Contingencies [Line Items]
Expected milestone payments		$ 2,000,000.0
Regulatory and Sales Milestones [Member]
Commitments And Contingencies [Line Items]
Research and development expense related to milestone expense							$ 300,000
Milestone payments							300,000
Intangible asset related to milestone			$ 500,000				500,000
Milestone payments related to intangible assets							$ 500,000

Insider Trading Arrangements - Director and Officer [Member]	3 Months Ended
	Dec. 31, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Stock-Based Compensation - Summary of Activity Relating to Restricted Stock Units (Detail) - Restricted Stock Units [Member]	12 Months Ended
	Dec. 31, 2023 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding, Shares at beginning balance \| shares	1,415,481
Granted, Shares \| shares	2,639,729
Vested, Shares \| shares	(326,530)
Forfeited, Shares \| shares	(640,286)
Outstanding, Shares at ending balance \| shares	3,088,394
Outstanding, Weighted Average Grant Date Fair Value at beginning balance \| $ / shares	$ 48.73
Granted, Weighted Average Grant Date Fair Value \| $ / shares	30.38
Vested, Weighted Average Grant Date Fair Value \| $ / shares	51.06
Forfeited, Weighted Average Grant Date Fair Value \| $ / shares	41.63
Outstanding, Weighted Average Grant Date Fair Value at ending balance \| $ / shares	$ 34.27

Net Loss Per Share

12 Months Ended

Dec. 31, 2023

Earnings Per Share [Abstract]

Net Loss Per Share

10.

Net Loss Per Share

The following table shows the calculation of basic and diluted net loss per share for the years ended December 31, 2023, 2022 and 2021:


	Year Ended December 31,
	2023			2022			2021
Basic net loss per share:
Numerator:
Net loss (in thousands)	$	(541,489	)	$	(532,784	)	$	(457,892	)
Denominator:
Weighted average common stock outstanding - basic and diluted		59,836,441			59,306,094			58,670,230
Net loss per share - basic and diluted	$	(9.05	)	$	(8.98	)	$	(7.80	)

The following table summarizes potential dilutive securities outstanding at the end of each reporting period that were excluded from the calculation of diluted net loss per share because including them would have been anti-dilutive as of December 31, 2023, 2022 and 2021:


	Year Ended December 31,
	2023		2022		2021
Stock options		7,663,041		7,138,350		6,599,429
Restricted stock units		1,662,363		160,403		563,334
Employee stock purchase plan		61,402		76,105		23,625
		9,386,806		7,374,858		7,186,388

Stock options and restricted stock units that are outstanding and contain performance-based vesting criteria for which the performance conditions have not been met are excluded from the calculation of potential dilutive securities above.

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Total revenue	$ 86,455	$ 7,686	$ 6,308
Operating costs and expenses:
Cost of revenues	2,159	813	553
Research and development	356,235	326,163	283,166
Selling, general and administrative	274,524	227,699	183,498
Restructuring	33,386
Total operating costs and expenses	666,304	554,675	467,217
Loss from operations	(579,849)	(546,989)	(460,909)
Interest income, net	38,743	14,190	2,883
Other income (expense), net	(383)	15	134
Net loss	$ (541,489)	$ (532,784)	$ (457,892)
Net loss per share - basic	$ (9.05)	$ (8.98)	$ (7.8)
Net loss per share - diluted	$ (9.05)	$ (8.98)	$ (7.8)
Weighted average number of common shares outstanding—basic	59,836,441	59,306,094	58,670,230
Weighted average number of common shares outstanding—diluted	59,836,441	59,306,094	58,670,230
Comprehensive loss:
Net Income (Loss)	$ (541,489)	$ (532,784)	$ (457,892)
Other comprehensive items:
Unrealized gain (loss) on marketable securities	9,392	(7,546)	(3,075)
Total comprehensive loss	(532,097)	(540,330)	(460,967)
Product Revenue [Member]
Total revenue	10,454	$ 7,686	$ 6,308
License And Milestone Revenue - Related Party [Member]
Total revenue	75,000
Collaboration Revenue - Related Party [Member]
Total revenue	824
Other Collaboration Revenue [Member]
Total revenue	$ 177

Fair Value Measurements - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Debt Instrument Fair Value Carrying Value [Line Items]
Accrued interest receivable written off	$ 0	$ 0
Transfers among the Level 1, Level 2 and Level 3 categories	0	0
Impairment of assets	0	0
Prepaid Expenses and Other Current Assets [Member]
Debt Instrument Fair Value Carrying Value [Line Items]
Accrued interest receivable	4,200,000	4,200,000
US Treasury Bond Securities \| Corporate Bonds and Municipal Securities [Member]
Debt Instrument Fair Value Carrying Value [Line Items]
Marketable securities fair value held to maturity	$ 110,300,000	$ 211,200,000
Maximum [Member] \| US Treasury Bond Securities \| U.S. Corporate Bonds [Member]
Debt Instrument Fair Value Carrying Value [Line Items]
Marketable securities, remaining contractual maturities	1 year	1 year
Maximum [Member] \| US Treasury Bond Securities \| Corporate Bonds and Municipal Securities [Member]
Debt Instrument Fair Value Carrying Value [Line Items]
Marketable securities held, matuirity period	2 years	2 years
Minimum [Member] \| US Treasury Bond Securities \| Corporate Bonds and Municipal Securities [Member]
Debt Instrument Fair Value Carrying Value [Line Items]
Marketable securities held, matuirity period	1 year	1 year

Collaboration Agreements

12 Months Ended

Dec. 31, 2023

Shionogi Collaboration Agreement [Member]

Collaboration Agreement

Collaboration Agreements

Shionogi

In June 2018, the Company entered into a strategic collaboration with Shionogi for the clinical development and commercialization of zuranolone for the treatment of MDD and other potential indications in Japan, Taiwan and South Korea (the “Shionogi Territory”). In October 2018, the Company entered into a supply agreement with Shionogi for the Company to supply zuranolone clinical material to Shionogi.

Under the terms of the collaboration agreement, Shionogi is responsible for all clinical development and regulatory filings for zuranolone in MDD and other indications in the Shionogi Territory and would be responsible for commercialization of zuranolone in the Shionogi Territory, if zuranolone is successfully developed and obtains marketing approval in any of the countries within the Shionogi Territory. Shionogi was required to make an upfront payment to the Company of $90.0 million, and the Company will be eligible to receive additional payments of up to $485.0 million if certain regulatory and commercial milestones are achieved by Shionogi. The potential future milestone payments include up to $70.0 million for the achievement of specified regulatory milestones, up to $30.0 million for the achievement of specified commercialization milestones, and up to $385.0 million for the achievement of specified net sales milestones. The Company is eligible to receive tiered royalties on sales of zuranolone in the Shionogi Territory, if development efforts are successful, with tiers averaging in the low to mid-twenty percent range, subject to other terms of the agreement. Shionogi has also granted to the Company certain rights to co-promote zuranolone in Japan. As between the Company and Shionogi, the Company maintains exclusive rights to develop and commercialize zuranolone outside of the Shionogi Territory. The upfront cash payment and any payments for milestones and royalties are non-refundable and non-creditable. Due to the uncertainty of pharmaceutical development and the high historical failure rates generally associated with drug development, the Company may not receive any milestone payments or any royalty payments from Shionogi.

The Company concluded that Shionogi meets the definition of a customer because the Company is delivering intellectual property and know-how rights for the zuranolone program in support of territories in which the parties are not jointly sharing the risks and rewards. In addition, the Company determined that the Shionogi collaboration met the requirements to be accounted for as a contract, including that it is probable that the Company will collect the consideration to which the Company is entitled in exchange for the goods or services that will be delivered to Shionogi.

The Company determined that the performance obligations in the Shionogi collaboration agreement included the license to zuranolone and the supply of certain materials during the clinical development phase, which includes the supply of API. The performance obligation related to the license to zuranolone was determined to be distinct from other performance obligations and therefore was a separate performance obligation for which control was transferred upon signing. The obligation to provide certain clinical materials, including API for use during the development period, was determined to be a separate performance obligation. Given that Shionogi is not obligated to purchase any minimum amount or quantities of commercial API, the supply of API to Shionogi for commercial use was determined to be an option for Shionogi, rather than a performance obligation of the Company at contract inception and will be accounted for if and when exercised. The Company also determined that there was no separate material right in connection with the supply of API for commercial use as the expected pricing was not at a discount. Given this fact pattern, the Company has concluded the agreement has two performance obligations.

Under the clinical supply agreement, the Company is obligated to manufacture and supply to Shionogi (i) clinical quantities of API reasonably required by Shionogi for the development of licensed products in the Shionogi territory under the collaboration and license agreement and (ii) quantities of drug product reasonably required for use by Shionogi in Phase 1 clinical trials of zuranolone in the Shionogi territory under the collaboration and license agreement, in the quantities agreed to by the parties. Collaboration revenue from the clinical supply agreement, which is shown as other collaboration revenue, pertains to the clinical material sold under the terms of the clinical supply agreement. The Company records the costs related to the clinical supply agreement in research and development expense on its consolidated statements of operations and comprehensive loss. During the year ended December 31, 2023, $0.2 million of collaboration revenue was recognized related to the Company’s agreement with Shionogi. During the years ended December 31, 2022, and 2021, no collaboration revenue was recognized related to the Company’s agreement with Shionogi.

The Company completed the evaluation of the standalone selling prices of each of the performance obligations and determined that the standalone selling price of the license performance obligation was $90.0 million. The Company recognized the transaction price allocated to the license performance obligation of $90.0 million as revenue during the quarter upon delivery of the license to Shionogi and resulting ability of Shionogi to use and benefit from the license, which was in the three months ended June 30, 2018. The remaining transaction price related to the performance obligation for the supply of certain clinical material is not significant. The potential milestone payments that the Company is eligible to receive were excluded from the transaction price, as all milestone amounts were fully constrained based on the probability of achievement. The Company will re-evaluate the transaction price at the end of each reporting period and as uncertain events are resolved or other changes in circumstances occur, and, if necessary, adjust its estimate of the transaction price.

Biogen

In November 2020, the Company entered into the Biogen Collaboration Agreement to jointly develop and commercialize SAGE-217 products for the treatment of MDD, PPD and other disorders and SAGE-324 products for essential tremor and other disorders. Concurrently, the Company also entered into a stock purchase agreement with BIMA (the “Biogen Stock Purchase Agreement”) under which BIMA purchased shares of the Company’s common stock. The Biogen Collaboration Agreement became effective on December 28, 2020 (the “Effective Date”).

Under the terms of the Biogen Collaboration Agreement, the Company granted Biogen co-exclusive licenses to develop and commercialize SAGE-217 products and SAGE-324 products (each, a “Product Class” and together, the “Licensed Products”) in the U.S., an exclusive license to develop and commercialize SAGE-217 products in all countries of the world other than the U.S. and the Shionogi Territory, and an exclusive license to develop and commercialize SAGE-324 products in all countries of the world other than the U.S. The Company refers to the territories outside the U.S.

to which Biogen has rights under the Biogen Collaboration Agreement with respect to the applicable Licensed Product as the “Biogen Territory”.

In connection with the effectiveness of the Biogen Collaboration Agreement and the closing of the sale of shares to BIMA in December 2020, the Company received $1.5 billion in consideration, comprised of an upfront payment of $875.0 million and the $650.0 million purchase price for 6,241,473 newly issued shares of the Company’s common stock (the “Biogen Shares”). As a result of the purchase of the Biogen Shares, Biogen is a related party of the Company.

The Company is eligible to receive additional payments of up to $1.6 billion from Biogen if certain regulatory and commercial milestones are achieved. The potential future milestone payments for SAGE-217 products include up to $475.0 million for the achievement of specified regulatory and commercial milestones, including a milestone payment of $75.0 million for the first commercial sale of ZURZUVAE for the treatment of women with PPD in the U.S. which was achieved in the fourth quarter of 2023 and, if approved, a milestone payment of $150.0 million for the first commercial sale of ZURZUVAE for the treatment of MDD in the U.S., and up to $300.0 million for the achievement of specified net sales milestones. The potential future milestone payments for SAGE-324 products include up to $520.0 million for the achievement of specified regulatory and commercial milestones and up to $300.0 million for the achievement of specified net sales milestones. The Company is also eligible to receive tiered royalties on net sales of SAGE-217 products and SAGE-324 products in the Biogen Territory at percentage rates ranging from the high teens to low twenties.

Due to the uncertainty of pharmaceutical development and the high historical failure rates generally associated with drug development, and the challenges of launching and commercializing a product, if approved, the Company may never receive any additional milestone payments or any royalty payments under the Biogen Collaboration Agreement.

Development and commercialization activities in the U.S. are conducted pursuant to plans agreed to by the Company and Biogen and overseen by a joint steering committee that consists at all times of an equal number of representatives of each party. The Company and Biogen share equally in the costs for development and commercialization, as well as the profits and losses upon FDA approval and commencement of product sales, in the U.S., subject to the Company’s opt-out right described below. Biogen is solely responsible for all development activities and costs related to any development and commercialization of SAGE-217 products and SAGE-324 products for the Biogen Territory, and the Company will receive royalties on any sales in the Biogen Territory, as mentioned above. Biogen is the principal and records sales of SAGE-217 products globally. If approved, the Company will be the principal and record sales of SAGE-324 products in the U.S. and Biogen will be the principal and record sales of SAGE-324 products in the Biogen Territory.

The Company is obligated to supply API and bulk drug product for the Biogen Territory and API, bulk drug product and final drug product for the U.S. to support development and commercialization activities. Biogen has the right to assume manufacturing responsibilities for API for the Biogen Territory at any time during the term of the agreement and will, within a reasonable period of time after the Effective Date, assume manufacturing responsibility for bulk drug product for the Biogen Territory.

Unless terminated earlier, the Biogen Collaboration Agreement will continue on a Licensed Product-by-Licensed Product and country-by-country basis until the date on which (a) in any country in the Biogen Territory, the royalty term has expired for all Licensed Products in a Product Class in such country, and (b) for the U.S., the parties agree to permanently cease to commercialize all Licensed Products in a Product Class. Biogen also has the right to terminate the Biogen Collaboration Agreement for convenience in its entirety, on a Product Class-by-Product Class basis or as to a particular region, upon advance written notice. The Company has an opt-out right to convert the co-exclusive licenses in the U.S. to an exclusive license to Biogen on a Product Class-by-Product Class basis. Following the exercise of the opt-out right, the Company would no longer share equally in the profits and losses in the U.S. and would be entitled to receive certain royalty payments at percentage rates ranging from the high teens to low twenties and additional sales milestones.

The Company concluded that the Biogen Collaboration Agreement and the Biogen Stock Purchase Agreement should be combined and treated as a single arrangement for accounting purposes as the agreements were entered into contemporaneously and in contemplation of one another. The Company determined that the combined agreements had elements that were within the scope of Topic 606 and Topic 808.

As of the Effective Date, the Company identified the following promises in the Biogen Collaboration Agreement that were evaluated under the scope of Topic 606: delivery of (i) a co-exclusive license for SAGE-217 products in the U.S.; (ii) an exclusive license for SAGE-217 products in the Biogen Territory; (iii) a co-exclusive license for SAGE-324 products in the U.S.; (iv) an exclusive license for SAGE-324 products in the Biogen Territory; (v) the clinical manufacturing supply of API and bulk drug product for SAGE-217 products in the Biogen Territory; and (vi) the clinical manufacturing supply of API and bulk drug product for SAGE-324 products in the Biogen Territory.

The Company also evaluated whether certain options outlined within the Biogen Collaboration Agreement represented material rights that would give rise to a performance obligation and concluded that none of the options convey a material right to Biogen and therefore are not considered separate performance obligations within the Biogen Collaboration Agreement.

The Company assessed the above promises and determined that the co-exclusive licenses for SAGE-217 products and SAGE-324 products in the U.S. are reflective of a vendor-customer relationship and therefore represent performance obligations within the scope of Topic 606. The co-exclusive license for SAGE-217 products and SAGE-324 products in the U.S. are considered functional intellectual property and distinct from other promises under the contract. The exclusive licenses for SAGE-217 products and SAGE-324 products in the Biogen Territory are considered functional licenses that are distinct in the context of the Biogen Collaboration Agreement as Biogen can benefit from the licenses on its own or together with other readily available resources. As the co-exclusive licenses in the U.S. and the exclusive licenses in the Biogen Territory are delivered at the same time, they are considered one performance obligation at contract inception. The clinical manufacturing supply of API and bulk drug product for SAGE-217 products and SAGE-324 products for the Biogen Territory are considered distinct in the context of the Biogen Collaboration Agreement as Biogen can benefit from the manufacturing services together with the licenses transferred by the Company at the inception of the agreement. Therefore, each represents a separate performance obligation within a contract with a customer under the scope of Topic 606 at contract inception.

The Company determined the transaction price under Topic 606 at the inception of the Biogen Collaboration Agreement to be $1.1 billion, consisting of the upfront payment of $875.0 million plus $232.5 million in excess proceeds from the equity investment under the Biogen Stock Purchase Agreement, when measured at fair value, plus future variable consideration for manufacturing supply of clinical API and bulk drug product for the Biogen Territory. The amount of variable consideration related to the future manufacturing services was not material. At inception, the Company determined that any variable consideration related to clinical development and regulatory or commercial milestones is deemed to be fully constrained and therefore excluded from the transaction price due to the high degree of uncertainty and risk associated with these potential payments, as the Company determined that it could not assert that it was probable that a significant reversal in the amount of cumulative revenue recognized will not occur. The Company also determined that royalties and sales milestones relate solely to the licenses of intellectual property and are therefore excluded from the transaction price under the sales- or usage-based royalty exception of Topic 606. Revenue related to these royalties and sales milestones will only be recognized when the associated sales occur, and relevant thresholds are met. As such, the entirety of the $1.1 billion transaction price was allocated to the transfer of the co-exclusive licenses for SAGE-217 products and SAGE-324 products in the U.S. and the exclusive licenses for SAGE-217 products and SAGE-324 products in the Biogen Territory and was recognized as license revenue during the year ended December 31, 2020.

In the fourth quarter of 2023 the Company achieved a milestone for the first commercial sale of ZURZUVAE for the treatment of women with PPD in the U.S. and recognized license and milestone revenue – related party of $75.0 million during the year ended December 31, 2023. During the years ended December 31, 2022 and 2021, no license and milestone revenue – related party was recognized related to the Biogen Collaboration Agreement.

The Company considers the collaborative activities associated with the co-development, co-commercialization, and co-manufacturing of SAGE-217 products and SAGE-324 products in the U.S. to be separate units of account within the scope of Topic 808 as the Company and Biogen are both active participants in the development and commercialization activities and are exposed to significant risks and rewards that are dependent on the development and commercial success of the activities in the arrangement.

While Biogen is considered the principal in transactions with customers for the sale of ZURZUVAE globally, the Company is also engaged in significant commercialization activities, including maintaining its own U.S. direct sales force. The Company presents its proportionate share of Biogen’s ZURZUVAE sales to customers in the U.S. as collaboration revenue - related party. Payments to or reimbursements from Biogen related to the agreement of the parties to share equally in all revenue and costs are accounted for as an increase to collaboration revenue, an increase to or reduction of cost of revenues, research and development expenses, or selling, general and administrative expenses, in the Consolidated Statement of Operations, depending on the nature of the activity.

To record its proportionate share of collaboration revenue from Biogen’s sales of ZURZUVAE to customers in the U.S., the Company utilizes certain information from Biogen, including revenue from the sale of the product and associated reserves on revenue.

The following table summarizes the Company’s proportionate share of the activity under the Biogen Collaboration Agreement accounted for under Topic 808, including activities associated with the sale of ZURZUVAE in the U.S., as well as ongoing costs related to the development of SAGE-217 and SAGE-324, as reflected in our statement of operations and comprehensive loss:


	Year Ended December 31,
	2023		2022		2021
	(in thousands)
Collaboration revenue - related party	$	824	$	—	$	—
Cost of revenues		504		—		—
Research and development expenses		94,325		86,028		84,221
Selling, general and administrative expenses		89,599		51,870		18,425

The revenue, cost and expense categories in the table above reflects the following reimbursement amounts to (from) Biogen to account for the sharing of economics under the Biogen Collaboration Agreement:


	Year Ended December 31,
	2023			2022			2021
	(in thousands)
Collaboration revenue - related party	$	(824	)	$	—		$	—
Cost of revenues		504			—			—
Research and development expenses		(76,208	)		(73,227	)		(79,848	)
Selling, general and administrative expenses		16,496			(2,230	)		(11,282	)

As of December 31, 2023, the Company recorded a collaboration receivable – related party of $83.0 million, consisting of $8.0 million of net reimbursement for amounts due for the three months ended December 31, 2023 and the $75.0 million milestone achieved. During the year ended December 31, 2023, no payments were made to Biogen and the Company received $65.7 million from Biogen for the amounts due for the three months ended December 31, 2022 and the nine months ended September 30, 2023. During the year ended December 31, 2022, no payments were made to Biogen and the Company received $80.3 million from Biogen for the amounts due for the three months ended December 31, 2021 and the nine months ended September 30, 2022. During the year ended December 31, 2021, no payments were made to Biogen and the Company received $72.6 million from Biogen for the amounts due for the nine months ended September 30, 2021.

Accounting for the Biogen Stock Purchase Agreement

In connection with the execution of the Biogen Collaboration Agreement, the Company and BIMA entered into the Biogen Stock Purchase Agreement. Pursuant to the Biogen Stock Purchase Agreement, the Company sold the Biogen Shares to BIMA at a price of approximately $104.14 per share for aggregate consideration of $650.0 million. The sale of the shares to BIMA closed on December 31, 2020.

The Biogen Stock Purchase Agreement includes certain standstill provisions that terminate on the earliest of (i) a specified regulatory milestone under the Biogen Collaboration Agreement, (ii) the date one year following the termination of the Biogen Collaboration Agreement and (iii) the seventh anniversary of the Effective Date.

The Company determined the fair value of the common shares was determined to be $417.5 million, which was $232.5 million less than the proceeds received from BIMA for the issuance of the Company’s common stock under the Biogen Stock Purchase Agreement. As such, the $232.5 million in excess proceeds has been included in the $1.1 billion transaction price of the Biogen Collaboration Agreement determined above.

Stock-Based Compensation

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Stock-Based Compensation

Equity Plans

On July 2, 2014, the stockholders of the Company approved the 2014 Stock Option and Incentive Plan (the “2014 Plan”), which became effective immediately prior to the completion of the Company’s IPO. The 2014 Plan provides for the grant of restricted stock awards, restricted stock units, incentive stock options and non-statutory stock options. The 2014 Plan replaced the Company’s 2011 Stock Option and Grant Plan (the “2011 Plan”). The Company no longer grants stock options or other awards under its 2011 Plan, but any stock options outstanding under the 2011 Plan remain outstanding and effective in accordance with their terms.

The 2014 Plan provides for an annual increase, to be added on the first day of each fiscal year, by up to 4% of the Company’s outstanding shares of common stock as of the last day of the prior year. On January 1, 2023, 2,380,365 shares of common stock, representing 4% of the Company’s outstanding shares of common stock as of December 31, 2022, were added to the 2014 Plan.

On December 15, 2016, the Board approved the 2016 Inducement Equity Plan (as amended and restated, the “2016 Plan”). The 2016 Plan provides for the grant of equity awards to individuals who have not previously been an employee or a non-employee director of the Company to induce them to accept employment and to provide them with a proprietary interest in the Company. On September 20, 2018, the Board amended the 2016 Plan to increase the total number of shares reserved for issuance by 1,200,000 shares.

Terms of equity grants, including vesting requirements, are determined by the Board or the Compensation Committee of the Board, subject to the provisions of the applicable plan. Stock options granted by the Company that are not performance-based are considered time-based because they vest based on the continued service of the grantee with the Company during a specified period following grant. These awards, when granted to employees, generally vest ratably over four years, with 25% vesting at the one-year anniversary through December 31, 2023. Stock option awards generally expire 10 years after the date of grant.

As of December 31, 2023, the total number of shares underlying outstanding awards under all equity plans was 11,206,435 and the total number of shares available for future issuance under all equity plans was 7,407,863 shares.

Restricted Stock Units

The following table summarizes activity relating to time-based restricted stock units and performance restricted stock units:


	Shares			Weighted Average Grant Date Fair Value
Outstanding as of December 31, 2022		1,415,481		$	48.73
Granted		2,639,729		$	30.38
Vested		(326,530	)	$	51.06
Forfeited		(640,286	)	$	41.63
Outstanding as of December 31, 2023		3,088,394		$	34.27

Time-based restricted stock units

During the years ended December 31, 2023, 2022 and 2021 there were 51,851, 366,014, and 113,941 time-based restricted stock units that vested, respectively. The fair value on the date of vesting for the years ended December 31, 2023, 2022 and 2021 was $1.8 million, $12.4 million, and $8.8 million, respectively.

At December 31, 2023, 1,662,363 time-based restricted stock units were both outstanding and unvested, and the total unrecognized stock-based compensation expense related to these awards was $40.2 million, which is expected to be recognized over the remaining weighted average vesting period of 1.71 years.

Performance restricted stock units

During the year ended December 31, 2021, the Company granted 531,176 performance restricted stock units to employees of the Company. These performance restricted stock units are related to the achievement of certain clinical and regulatory development milestones related to product candidates and commercial milestones.

During the year ended December 31, 2022, the Company granted 705,380 performance restricted stock units to its employees and consultants. The majority of these performance restricted stock units vest upon the achievement of certain clinical and regulatory development milestones related to product candidates and commercial milestones.

During the year ended December 31, 2023, the Company granted 905,012 performance restricted stock units to its employees and consultants. The majority of these performance restricted stock units vest upon the achievement of certain clinical and regulatory development milestones related to product candidates and commercial milestones. Certain performance restricted stock units vest upon the Company reaching specified measures of total stockholder return.

Recognition of stock-based compensation expense associated with performance restricted stock units, except for those with milestones that are measures of total stockholder return, commences when the performance condition is considered probable of achievement, using management’s best estimates, which consider the inherent risk and uncertainty regarding the future outcomes of the milestones. Recognition of stock-based compensation associated with performance restricted stock units with milestones that are measures of total stockholder return commences on the grant date and is recorded independently of the vesting outcomes of the grants.

As of December 31, 2023, 2022 and 2021, for performance restricted stock units that were outstanding, and other than performance restricted stock units for which vesting is tied to total stockholder return, the achievement of the milestones that had not been met was considered not probable, and therefore no expense has been recognized related to these awards in the years ended December 31, 2023, 2022 and 2021, respectively. During the year ended December 31, 2023, the Company recorded $0.7 million of stock-based compensation expense related to performance restricted stock units for which vesting is tied to total stockholder return.

During the year ended December 31, 2021, two milestones for outstanding performance restricted stock units were achieved. The total fair value of the performance restricted stock units that vested upon achievement of these milestones was $9.5 million, and the Company recognized stock-based compensation expense related the vesting of these performance restricted stock units of $16.6 million.

No performance restricted stock units vested during the year ended December 31, 2022.

During the year ended December 31, 2023, three vesting milestones for outstanding performance restricted stock units were achieved. The total fair value of the performance restricted stock units that vested upon achievement of these milestones was $9.6 million, and the Company recognized stock-based compensation expense related to the vesting of these performance restricted stock units of $14.3 million.

At December 31, 2023, 1,426,031 performance restricted stock units were both outstanding and unvested, and the total unrecognized stock-based compensation expense related to these awards was $65.8 million.

Stock Option Rollforward

The following table summarizes activity related to time-based and performance-based stock options:


	Shares			Weighted Average Exercise Price		Weighted Average Remaining Life (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding as of December 31, 2022		7,788,350		$	77.95		6.36	$	7,275
Granted		964,253		$	44.58
Exercised		(65,940	)	$	16.58
Forfeited		(568,622	)	$	56.00
Outstanding as of December 31, 2023		8,118,041		$	76.02		5.66	$	475
Vested and expected to vest as of December 31, 2023		7,389,812		$	76.55		5.47	$	455
Exercisable as of December 31, 2023		6,116,989		$	81.94		4.84	$	403

As of December 31, 2023, the Company had unrecognized stock-based compensation expense related to its outstanding and unvested time-based stock option awards of $42.7 million, which is expected to be recognized over the remaining weighted average vesting period of 2.76 years.

The intrinsic value of stock options exercised during the years ended December 31, 2023, 2022 and 2021 was $1.9 million, $4.4 million and $9.0 million, respectively.

Performance-Based Stock Options

Recognition of stock-based compensation expense associated with performance-based stock options commences when the performance condition is considered probable of achievement, using management’s best estimates, which consider the inherent risk and uncertainty regarding the future outcomes of the milestones.

As of December 31, 2023, 2022 and 2021, for performance-based stock option grants that were outstanding, the achievement of the milestones that had not been met was considered not probable, and therefore no expense has been recognized related to these awards in the years ended December 31, 2023, 2022 and 2021, respectively.

During the year ended December 31, 2021, in connection with the hiring of its chief executive officer, the Company granted 650,000 stock options to its chief executive officer to purchase shares of common stock that contain performance-based vesting criteria, such that the shares underlying such stock options will vest upon the achievement of certain regulatory and commercial milestones. During the years ended December 31, 2023 and 2022, the Company granted no stock options to purchase shares of common stock that contain performance-based vesting criteria.

During the years ended December 31, 2022, and 2021, no milestones were achieved under performance-based stock options.

During the year ended December 31, 2023, one regulatory development milestone was achieved under performance-based stock options granted in connection with the hiring of its chief executive officer. Stock options with this milestone were granted during the year ended December 31, 2021. During the year ended December 31, 2023, the Company recognized stock-based compensation expense related to this milestone of $10.7 million.

As of December 31, 2023, 455,000 performance-based stock options were both outstanding and unvested, the total unrecognized stock-based compensation expense related to these awards was $24.9 million before the application of the forfeiture rate and the timing of recognition of this stock-based compensation expense is subject to judgment of the Company as to when the performance conditions are considered probable of being achieved.

Stock-Based Compensation Expense

The following table summarizes stock-based compensation expense recognized during the years ended December 31, 2023, 2022 and 2021:


	Year Ended December 31,
	2023		2022		2021
	(in thousands)
Research and development	$	24,813	$	25,888	$	49,746
Selling, general and administrative		47,716		35,714		54,883
Restructuring		838		—		—
	$	73,367	$	61,602	$	104,629

The stock-based compensation expense of $0.8 million recorded for the restructuring in the year ended December 31, 2023 is the incremental amount related to modifying the exercise period for outstanding, vested stock option grants that had been granted to employees whose employment was terminated in the restructuring. The expense was recorded within the restructuring expenses on the consolidated statements of operations and comprehensive loss.

The following table summarizes stock-based compensation expense by award type recognized during the years ended December 31, 2023, 2022 and 2021:


	Year Ended December 31,
	2023		2022		2021
	(in thousands)
Stock options	$	47,695	$	54,971	$	78,516
Restricted stock units		24,424		5,587		25,375
Employee stock purchase plan		1,248		1,044		738
	$	73,367	$	61,602	$	104,629

For stock option awards, the fair value is estimated at the grant date using the Black-Scholes option-pricing model, taking into account the terms and conditions upon which stock options are granted. For grants with service based vesting conditions, the fair value of the stock options is amortized on a straight-line basis for stock option awards to employees, non-employee directors and non-employee consultants over the requisite service period of the awards.

The weighted average grant date fair value per share of stock options granted under the Company’s stock option plans during the years ended December 31, 2023, 2022 and 2021 was $29.53, $25.96 and $51.87, respectively.

The fair value of each stock option granted under the Company’s equity plans has been calculated on the date of grant using the following weighted average assumptions:


	Year Ended December 31,
	2023			2022			2021
Expected dividend yield		0	%		0	%		0	%
Expected volatility		72	%		73	%		76	%
Risk-free interest rate		3.85	%		2.49	%		0.63	%
Expected term	6.01 years			6.03 years			5.92 years

Expected dividend yield: the Company has not paid, and does not anticipate paying, any dividends in the foreseeable future.

Risk-free interest rate: the Company determined the risk-free interest rate by using a weighted average equivalent to the expected term based on the U.S. Treasury yield curve in effect as of the date of grant.

Expected volatility: the Company uses the historical volatility of its publicly traded common stock, as there is adequate historical data for the duration of the expected term.

Expected term (in years): the expected term represents the period that the Company’s stock option grants are expected to be outstanding. The expected term of the stock options granted to employees, non-employee directors and non-employee consultants by the Company has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” stock options. Under this approach, the weighted average expected life is presumed to be the average of the vesting term and the contractual term of the stock option. This approach is used because the Company does not have sufficient historical exercise data to provide a reasonable basis upon which to estimate the expected term due to the limited period of time that its stock has been publicly traded.

Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from estimates. The Company estimates forfeitures based on historical terminations. For the years ended December 31, 2023, 2022 and 2021, the weighted-average forfeiture rates were 16.6%, 19.2% and 16.7%, respectively.

2014 Employee Stock Purchase Plan

On July 2, 2014, the Company’s stockholders approved the 2014 Employee Stock Purchase Plan (the “ESPP”), which had been previously approved by the Board. The ESPP became effective upon the completion of the IPO. A total of 282,000 shares of common stock were authorized for issuance under the ESPP.

On June 16, 2022, the Company’s stockholders approved an amendment to the ESPP to add 300,000 shares of common stock to the ESPP.

On June 16, 2023, the Company’s stockholders approved an amendment to the ESPP to add 500,000 shares of common stock to the ESPP.

As of December 31, 2023, 445,920 shares have been issued and 636,080 shares are available for issuance under the ESPP. At December 31, 2023, accrued expenses includes $0.4 million of stock-based compensation expense related to an enrollment period for which the related shares had not been issued as of December 31, 2023.

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Summary of Income (Loss) Before Income Tax Expense

Loss before income tax expense consists of the following:


	Year Ended December 31,
	2023			2022			2021
	(in thousands)
Domestic	$	(541,656	)	$	(532,539	)	$	(457,693	)
Foreign		167			(245	)		(199	)
	$	(541,489	)	$	(532,784	)	$	(457,892	)

Summary of Reconciliation of U.S. Statutory Rate to Company's Effective Tax Rate

A reconciliation of the U.S. statutory rate to the Company’s effective tax rate is as follows:


	Year Ended December 31,
	2023			2022			2021
Tax due at statutory rate		21.0	%		21.0	%		21.0	%
State taxes, net of federal		4.1			1.8			1.9
Stock-based compensation		(1.7	)		(1.9	)		(5.2	)
Federal and state tax credits		2.4			2.1			3.5
Change in valuation allowance		(26.2	)		(23.0	)		(20.7	)
Other		0.4			—			(0.5	)
		0.0	%		0.0	%		0.0	%

Summary of Significant Components of Company's Net Deferred Tax Asset

Significant components of the Company’s net deferred tax assets at December 31, 2023 and 2022 are as follows:


	December 31,
	2023			2022
	(in thousands)
Net operating losses	$	428,785		$	347,880
Tax credits		133,602			118,393
Capitalized research and development expenses		110,690			66,849
Stock-based compensation		53,860			49,916
Accrued expenses		7,018			8,750
Depreciation and amortization		1,456			1,386
Lease liability		1,207			2,803
Right of use asset		(1,042	)		(2,433	)
Other		(382	)		(258	)
Total net deferred tax asset before valuation allowance		735,194			593,286
Valuation allowance		(735,194	)		(593,286	)
	$	—		$	—

Summary of Gross Unrecognized Tax Benefits Excluding Interest and Penalties

The following table reconciles the beginning and ending amounts of gross unrecognized tax benefits, excluding interest and penalties, if any, for the years ended December 31, 2023, 2022 and 2021:


	2023		2022		2021
	(in thousands)
Balance as of January 1	$	6,846	$	6,084	$	—
Increases related to current year tax positions		655		697		396
Increases related to prior year tax positions		242		65		5,688
Balance as of December 31	$	7,743	$	6,846	$	6,084

Balance Sheet Components (Tables)

12 Months Ended

Dec. 31, 2023

Balance Sheet Related Disclosures [Abstract]

Summary of Property and Equipment, Net

The following table summarizes property and equipment, net, as of December 31, 2023 and 2022:


	December 31,			December 31,
	2023			2022
	(in thousands)
Computer hardware and software	$	2,114		$	1,771
Furniture and equipment		1,786			1,714
Leasehold improvements		5,509			5,508
		9,409			8,993
Less: Accumulated depreciation		(7,488	)		(6,095	)
	$	1,921		$	2,898

Summary of Accrued Expenses

The following table summarizes accrued expenses as of December 31, 2023 and 2022:


	December 31,		December 31,
	2023		2022
	(in thousands)
Accrued research and development costs	$	26,040	$	32,565
Restructuring		10,589		—
Employee-related		21,339		29,372
Professional services		8,589		10,172
Other		707		557
	$	67,264	$	72,666

Common Stock - Additional Information (Detail) - USD ($)		12 Months Ended
	Nov. 07, 2023	Dec. 31, 2023	Dec. 31, 2022
Subsidiary or Equity Method Investee [Line Items]
Common stock, shares authorized		120,000,000	120,000,000
Common stock, par value		$ 0.0001	$ 0.0001
Dividends declared		$ 0	$ 0
Voting rights		Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders.
Purchase of treasury stock, Shares		3,033
Total cost of shares held in treasury		$ 400,000	$ 400,000
Sales Agreement [Member]
Subsidiary or Equity Method Investee [Line Items]
Aggregate offering price of common stock shares issued	$ 250,000,000
Number of shares issued or sold		0
Sales Agreement [Member] \| Maximum [Member]
Subsidiary or Equity Method Investee [Line Items]
Percentage of sales commission	3.00%

Leases, Commitments and Contingencies - Schedule of Lease Expense by Lease Type Recognized (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Operating lease cost	$ 6,748	$ 6,748	$ 8,748
Variable lease cost	1,957	1,846	1,600
Short-term lease cost	20	206	101
Sublease income	(434)	(421)	(234)
Total	$ 8,291	$ 8,379	$ 10,215

Fair Value Measurements - Summary of Fair Value And Unrealized Losses of Marketable Securities In Loss Position (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	$ 343,373	$ 513,738
Less than 12 months, Unrealized Losses	(611)	(4,795)
Greater than 12 months, Fair Value	123,121	399,783
Greater than 12 months, Unrealized Losses	(640)	(5,455)
Fair Value	466,494	913,521
Unrealized Losses	(1,251)	(10,250)
U.S. Government Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	52,521	112,243
Less than 12 months, Unrealized Losses	(96)	(1,517)
Greater than 12 months, Fair Value	41,911	185,691
Greater than 12 months, Unrealized Losses	(251)	(2,745)
Fair Value	94,432	297,934
Unrealized Losses	(347)	(4,262)
U.S. Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	111,901	208,507
Less than 12 months, Unrealized Losses	(246)	(1,989)
Greater than 12 months, Fair Value	43,851	130,633
Greater than 12 months, Unrealized Losses	(238)	(1,541)
Fair Value	155,752	339,140
Unrealized Losses	(484)	(3,530)
International Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	43,708	50,982
Less than 12 months, Unrealized Losses	(87)	(497)
Greater than 12 months, Fair Value	6,014	68,993
Greater than 12 months, Unrealized Losses	(35)	(636)
Fair Value	49,722	119,975
Unrealized Losses	(122)	(1,133)
U.S. Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	7,848	24,768
Less than 12 months, Unrealized Losses	(1)	(120)
Fair Value	7,848	24,768
Unrealized Losses	(1)	(120)
International Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	37,300	30,987
Less than 12 months, Unrealized Losses	(38)	(175)
Fair Value	37,300	30,987
Unrealized Losses	(38)	(175)
U.S. Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	90,095	86,251
Less than 12 months, Unrealized Losses	(143)	(497)
Greater than 12 months, Fair Value	31,345	14,466
Greater than 12 months, Unrealized Losses	(116)	(533)
Fair Value	121,440	100,717
Unrealized Losses	$ (259)	$ (1,030)

Preferred Stock - Additional Information (Detail) - shares	Dec. 31, 2023	Dec. 31, 2022
Temporary Equity Disclosure [Abstract]
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0

Leases, Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2023

Commitments and Contingencies Disclosure [Abstract]

Schedule of Amount of Operating Leases

The following table shows the amounts of operating leases in the balance sheets as of December 31, 2023 and 2022:


		December 31,
Balance sheet location	Balance sheet caption	2023		2022
		(in thousands)
Assets
Right-of-use operating asset	Right-of-use operating asset	$	4,458	$	10,532

Liabilities
Current operating lease liabilities	Operating lease liability, current portion		5,165		7,643
Long-term operating lease liabilities	Operating lease liability, net of current portion		—		4,491
		$	5,165	$	12,134

Schedule of Lease Expense by Lease Type Recognized

The following table shows the amounts of lease expense by lease type that was recognized during the years ended December 31, 2023, 2022 and 2021:


	Year Ended December 31,
	2023			2022			2021
	(in thousands)
Operating lease cost	$	6,748		$	6,748		$	8,748
Variable lease cost		1,957			1,846			1,600
Short-term lease cost		20			206			101
Sublease income		(434	)		(421	)		(234	)
	$	8,291		$	8,379		$	10,215

Schedule of Minimum Lease Payments

The minimum lease payments are expected to be as follows:


Years Ending December 31,	(In thousands)
2024	$	5,316
Thereafter		—
Total lease payments		5,316
Less imputed interest		(151	)
Present value of operating lease liabilities	$	5,165

Schedule of Weighted Average Remaining Lease Term and Weighted Average Discount Rate of Our Operating Leases

The following table shows the weighted average remaining lease term and weighted average discount rate of the operating leases:


	Year ended December 31,
	2023	2022
Weighted average remaining lease term in years	0.69	1.68
Weighted average discount rate	7.5%	7.5%

Schedule of Supplemental Disclosure of Cash Flow Information Related to Operating Leases


	Year Ended December 31,
	2023		2022		2021
	(in thousands)
Cash paid for amounts included in the measurement of lease liabilities	$	7,643	$	7,468	$	9,264

Lease asset de-recognized upon lease cancellation
Operating leases	$	—	$	—	$	3,733

Collaboration Agreements - Additional Information (Detail) - USD ($)			3 Months Ended				9 Months Ended			12 Months Ended
	Nov. 30, 2020	Jun. 30, 2018	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jun. 30, 2018	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Jun. 12, 2018
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue										$ 86,455,000	$ 7,686,000	$ 6,308,000
Collaboration receivable - related party			$ 83,009,000	$ 13,660,000						83,009,000	13,660,000
Shionogi Collaboration Agreement [Member] \| Collaboration Revenue [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue										200,000	0	0
Shionogi Collaboration Agreement [Member] \| SAGE-217 [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment		$ 90,000,000.0
Average percentage on tiered royalties		20.00%
Revenue						$ 90,000,000.0
Standalone selling price of license performance obligation		$ 90,000,000.0				90,000,000.0
Shionogi Collaboration Agreement [Member] \| SAGE-217 [Member] \| Maximum [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Additional milestone payment receivable		485,000,000.0				$ 485,000,000.0
Shionogi Collaboration Agreement [Member] \| SAGE-217 [Member] \| Maximum [Member] \| Regulatory Milestones [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Future milestone payments		70,000,000.0
Shionogi Collaboration Agreement [Member] \| SAGE-217 [Member] \| Maximum [Member] \| Commercial Milestones [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Future milestone payments		30,000,000.0
Shionogi Collaboration Agreement [Member] \| SAGE-217 [Member] \| Maximum [Member] \| Sales Milestones [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Future milestone payments		$ 385,000,000.0
Biogen Collaboration Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration agreement effective date	Dec. 28, 2020
Upfront payment													$ 875,000,000.0
Revenue													1,100,000,000
Sale of stock, consideration received													$ 1,500,000,000
Public offering of common stock, net of offering costs, Shares													6,241,473
Purchase price													$ 650,000,000.0
Net reimbursement			8,000,000							(824,000)
Milestone achieved			75,000,000
Payments to related parties										0	0	0
Proceeds from related parties				$ 65,700,000	$ 80,300,000		$ 65,700,000	$ 80,300,000	$ 72,600,000
Biogen Collaboration Agreement [Member] \| Related Party [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration receivable - related party			$ 83,000,000							83,000,000
Biogen Collaboration Agreement [Member] \| License And Milestone Revenue - Related Party [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue										$ 75,000,000	$ 0	$ 0
Biogen Collaboration Agreement [Member] \| SAGE-217 [Member] \| Maximum [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Additional milestone payment receivable														$ 1,600,000,000
Biogen Collaboration Agreement [Member] \| SAGE-217 [Member] \| Maximum [Member] \| First Commercial Sale of Zurzuvae for Treatment of MDD [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Future milestone payments	$ 150,000,000
Biogen Collaboration Agreement [Member] \| SAGE-217 [Member] \| Maximum [Member] \| First Commercial Sale Of Zurzuvae For Treatment Of Women With Ppd [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Future milestone payments	75,000,000
Biogen Collaboration Agreement [Member] \| SAGE-217 [Member] \| Maximum [Member] \| Sales Milestones [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Future milestone payments	300,000,000
Biogen Collaboration Agreement [Member] \| SAGE-217 [Member] \| Maximum [Member] \| Regulatory and Commercial Milestones [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Future milestone payments	475,000,000
Biogen Collaboration Agreement [Member] \| SAGE-324 [Member] \| Maximum [Member] \| Sales Milestones [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Future milestone payments	300,000,000
Biogen Collaboration Agreement [Member] \| SAGE-324 [Member] \| Maximum [Member] \| Regulatory and Commercial Milestones [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Future milestone payments	$ 520,000,000
Biogen Stock Purchase Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment													875,000,000
Purchase price													650,000,000.0
Transaction price, total													1,100,000,000
Premium amount on equity investment													$ 232,500,000
Price per share													$ 104.14
Biogen stock purchase agreement, description										terminate on the earliest of (i) a specified regulatory milestone under the Biogen Collaboration Agreement, (ii) the date one year following the termination of the Biogen Collaboration Agreement and (iii) the seventh anniversary of the Effective Date.
Stock issued													$ 417,500,000

Net Loss Per Share (Tables)

12 Months Ended

Dec. 31, 2023

Earnings Per Share [Abstract]

Summary of Basic and Diluted Net Income (Loss) Per Share

The following table shows the calculation of basic and diluted net loss per share for the years ended December 31, 2023, 2022 and 2021:


	Year Ended December 31,
	2023			2022			2021
Basic net loss per share:
Numerator:
Net loss (in thousands)	$	(541,489	)	$	(532,784	)	$	(457,892	)
Denominator:
Weighted average common stock outstanding - basic and diluted		59,836,441			59,306,094			58,670,230
Net loss per share - basic and diluted	$	(9.05	)	$	(8.98	)	$	(7.80	)

Summary of Potential Dilutive Securities Outstanding


	Year Ended December 31,
	2023		2022		2021
Stock options		7,663,041		7,138,350		6,599,429
Restricted stock units		1,662,363		160,403		563,334
Employee stock purchase plan		61,402		76,105		23,625
		9,386,806		7,374,858		7,186,388

Income Taxes - Summary of Reconciliation of U.S. Statutory Rate to Company's Effective Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Tax due at statutory rate	21.00%	21.00%	21.00%
State taxes, net of federal	4.10%	1.80%	1.90%
Stock-based compensation	(1.70%)	(1.90%)	(5.20%)
Federal and state tax credits	2.40%	2.10%	3.50%
Change in valuation allowance	(26.20%)	(23.00%)	(20.70%)
Other	0.40%		(0.50%)
Total effective tax rate	0.00%	0.00%	0.00%

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Summary Of Significant Accounting Policies [Line Items]
Expected dividend yield	0.00%	0.00%	0.00%
Prepaid Expenses and Other Current Assets [Member]
Summary Of Significant Accounting Policies [Line Items]
Trade accounts receivables	$ 1.4	$ 1.5
Inventory	$ 1.5	$ 1.7
Product Revenue [Member]
Summary Of Significant Accounting Policies [Line Items]
Incremental costs incurred expected amortization period of asset	true

Collaboration Agreements (Tables)

12 Months Ended

Dec. 31, 2023

Collaboration Agreement [Abstract]

Summary of Activity and Reimbursement Amounts Related to Collaboration Agreement


	Year Ended December 31,
	2023		2022		2021
	(in thousands)
Collaboration revenue - related party	$	824	$	—	$	—
Cost of revenues		504		—		—
Research and development expenses		94,325		86,028		84,221
Selling, general and administrative expenses		89,599		51,870		18,425


	Year Ended December 31,
	2023			2022			2021
	(in thousands)
Collaboration revenue - related party	$	(824	)	$	—		$	—
Cost of revenues		504			—			—
Research and development expenses		(76,208	)		(73,227	)		(79,848	)
Selling, general and administrative expenses		16,496			(2,230	)		(11,282	)

Subsequent Events

12 Months Ended

Dec. 31, 2023

Subsequent Events [Abstract]

Subsequent Events

14. Subsequent Events

Office Space Lease

On January 22, 2024, the Company entered into a lease agreement (the “Lease”) for approximately 30,567 rentable square feet of office space in a multi-tenant building located in Cambridge, Massachusetts (the “Premises”). The Company will relocate its corporate headquarters to the Premises upon the expiration on August 31, 2024 of (i) the lease of 63,017 square feet of office space for the Company’s current headquarters at 215 First Street, Cambridge, Massachusetts, the first multi-tenant building; and (ii) the lease of 40,419 square feet of additional office space at 245 First Street, Cambridge, Massachusetts, the second multi-tenant building, each in accordance with its terms. The term of the Lease will commence on the later of (1) September 1, 2024, or (2) the date on which improvements to the premises are, or are deemed to be, substantially completed (the “Commencement Date”). The Company’s obligation for the payment of rent for the premises begins six months after the Commencement Date (the “Rent Commencement Date”). The Lease has an initial term of approximately sixty-six months, measured from the Commencement Date. The monthly base rent due under the Lease initially shall be $224,158 per month for the first year following the Rent Commencement Date and is scheduled to increase by approximately 3% per annum for each subsequent year. The Company has the option to extend the Lease one time for an additional five-year period, subject to the terms therein.

In connection with its entry into the Lease and as a security deposit, the Company has provided the landlord a letter of credit in the amount of approximately $1.4 million, which the Company and the landlord have agreed may be reduced to approximately $1.2 million following the third anniversary of the Rent Commencement Date, provided that no event of default by the Company has occurred. The landlord has the right to terminate the Lease upon customary events of default.

Option Exchange Program

On January 23, 2024, the Company initiated a tender offer related to a one-time stock option exchange program pursuant to which eligible non-executive officer employees are being given the opportunity to exchange certain outstanding stock options to purchase shares of the Company’s common stock for replacement options to purchase a lesser number of shares of common stock (the “Option Exchange”). Stock options eligible for exchange have an exercise price per share of $35.00 or greater, in addition to certain other requirements, and will be exchanged for replacement options with an exercise price per share equal to the fair market value of the Company’s common stock on the date of grant of the replacement options, which is currently expected to be February 21, 2024. Approximately 3.5 million outstanding stock options are eligible to be exchanged. All the replacement options will be granted in exchange for tendered options at ratios ranging from 1.50:1 to 5:00:1, depending on the current exercise price of the tendered option. Holders of eligible options may elect to tender their eligible options through the expiration of the offer period, which is currently expected to be February 20, 2024. The Company does not expect to incur significant additional stock-based compensation expense as a result of the Option Exchange. The consummation of the Option Exchange was subject to approval by the Company’s stockholders, which approval was received at the special meeting of stockholders held on January 31, 2024.

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2023

Fair Value Disclosures [Abstract]

Summary of Company's Cash Equivalents and Marketable Securities

The following tables summarize the Company’s cash equivalents and marketable securities as of December 31, 2023 and 2022:


	December 31, 2023
	Total		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
	(in thousands)
Cash equivalents:
Money market funds	$	59,852	$	59,852	$	—	$	—
U.S. government securities		8,695		—		8,695		—
Total cash equivalents		68,547		59,852		8,695		—
Marketable securities:
U.S. government securities		166,925		—		166,925		—
U.S. corporate bonds		210,198		—		210,198		—
International corporate bonds		97,675		—		97,675		—
U.S. commercial paper		23,370		—		23,370		—
International commercial paper		46,900		—		46,900		—
U.S. certificates of deposit		8,830		—		8,830		—
U.S. municipal securities		128,294		—		128,294		—
Total marketable securities		682,192		—		682,192		—
	$	750,739	$	59,852	$	690,887	$	—


	December 31, 2022
	Total		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
	(in thousands)
Cash equivalents:
Money market funds	$	161,185	$	161,185	$	—	$	—
Total cash equivalents		161,185		161,185		—		—
Marketable securities:
U.S. government securities		302,911		—		302,911		—
U.S. corporate bonds		354,495		—		354,495		—
International corporate bonds		127,248		—		127,248		—
U.S. commercial paper		63,114		—		63,114		—
International commercial paper		133,163		—		133,163		—
U.S. certificates of deposit		15,613		—		15,613		—
U.S. municipal securities		113,250		—		113,250		—
Total marketable securities		1,109,794		—		1,109,794		—
	$	1,270,979	$	161,185	$	1,109,794	$	—

Summary of Gross Unrealized Gains and Losses of Marketable Securities

The following tables summarize the gross unrealized gains and losses of the Company’s marketable securities as of December 31, 2023 and 2022:


	December 31, 2023
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Credit Losses		Fair Value
	(in thousands)
Assets:
U.S. government securities	$	167,165	$	107	$	(347	)	$	—	$	166,925
U.S. corporate bonds		210,491		191		(484	)		—		210,198
International corporate bonds		97,698		99		(122	)		—		97,675
U.S. commercial paper		23,360		11		(1	)		—		23,370
International commercial paper		46,935		3		(38	)		—		46,900
U.S. certificates of deposit		8,830		—		—			—		8,830
U.S. municipal securities		128,527		26		(259	)		—		128,294
	$	683,006	$	437	$	(1,251	)	$	—	$	682,192


	December 31, 2022
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Credit Losses		Fair Value
	(in thousands)
Assets:
U.S. government securities	$	307,173	$	—	$	(4,262	)	$	—	$	302,911
U.S. corporate bonds		358,019		6		(3,530	)		—		354,495
International corporate bonds		128,374		7		(1,133	)		—		127,248
U.S. commercial paper		63,234		—		(120	)		—		63,114
International commercial paper		133,338		—		(175	)		—		133,163
U.S. certificates of deposit		15,613		—		—			—		15,613
U.S. municipal securities		114,249		31		(1,030	)		—		113,250
	$	1,120,000	$	44	$	(10,250	)	$	—	$	1,109,794

Summary of Fair Value And Unrealized Losses of Marketable Securities In Loss Position


	December 31, 2023
	Less than 12 months					Greater than 12 months					Total
	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
	(in thousands)
U.S. government securities	$	52,521	$	(96	)	$	41,911	$	(251	)	$	94,432	$	(347	)
U.S. corporate bonds		111,901		(246	)		43,851		(238	)		155,752		(484	)
International corporate bonds		43,708		(87	)		6,014		(35	)		49,722		(122	)
U.S. commercial paper		7,848		(1	)		—		—			7,848		(1	)
International commercial paper		37,300		(38	)		—		—			37,300		(38	)
U.S. municipal securities		90,095		(143	)		31,345		(116	)		121,440		(259	)
	$	343,373	$	(611	)	$	123,121	$	(640	)	$	466,494	$	(1,251	)


	December 31, 2022
	Less than 12 months					Greater than 12 months					Total
	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
	(in thousands)
U.S. government securities	$	112,243	$	(1,517	)	$	185,691	$	(2,745	)	$	297,934	$	(4,262	)
U.S. corporate bonds		208,507		(1,989	)		130,633		(1,541	)		339,140		(3,530	)
International corporate bonds		50,982		(497	)		68,993		(636	)		119,975		(1,133	)
U.S. commercial paper		24,768		(120	)		—		—			24,768		(120	)
International commercial paper		30,987		(175	)		—		—			30,987		(175	)
U.S. municipal securities		86,251		(497	)		14,466		(533	)		100,717		(1,030	)
	$	513,738	$	(4,795	)	$	399,783	$	(5,455	)	$	913,521	$	(10,250	)

- Definition

Tabular disclosure of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-9

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (aa)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (aaa)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 8: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 9: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

Reference 10: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

Reference 11: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

Reference 12: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

+ Details

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities
Net loss	$ (541,489)	$ (532,784)	$ (457,892)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	73,367	61,602	104,629
Premium on marketable securities	(132)	(1,500)	(23,641)
Amortization of premium (discount) on marketable securities	(6,340)	5,853	13,046
Depreciation expense	1,393	1,122	4,182
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	19,001	(10,985)	(17,020)
Collaboration receivable - related party	(69,349)	4,846	(18,506)
Other long-term assets	(1,778)	(519)	(910)
Right-of-use operating asset	6,074	5,577	5,221
Operating lease liabilities, current	(2,478)	175	206
Operating lease liabilities, non-current	(4,491)	(6,473)	(5,944)
Accounts payable	(8,495)	8,433	6,689
Accrued expenses and other liabilities	(5,868)	4,617	11,758
Net cash used in operating activities	(540,585)	(460,036)	(378,182)
Cash flows from investing activities
Proceeds from sales and maturities of marketable securities	1,038,136	1,207,407	988,075
Purchases of marketable securities	(594,670)	(881,037)	(1,990,151)
Purchases of property and equipment	(553)	(937)	(372)
Net cash provided by (used in) investing activities	442,913	325,433	(1,002,448)
Cash flows from financing activities
Proceeds from stock option exercises and employee stock purchase plan issuances	6,930	3,113	14,719
Payment of employee tax obligations related to vesting of restricted stock units	(903)	(43)	(1,385)
Net cash provided by financing activities	6,027	3,070	13,334
Net decrease in cash, cash equivalents and restricted cash	(91,645)	(131,533)	(1,367,296)
Cash, cash equivalents and restricted cash at beginning of period	163,969	295,502	1,662,798
Cash, cash equivalents and restricted cash at end of period	$ 72,324	163,969	295,502
Supplemental disclosure of non-cash operating activities
Purchases of property and equipment included in accounts payable		$ 137	70
Lease asset de-recognized upon lease cancellation			$ 3,733

Subsequent Events - Additional Information (Details)			12 Months Ended
Subsequent Events - Additional Information (Details)	Jan. 23, 2024 $ / shares shares	Jan. 22, 2024 USD ($) ft²	Dec. 31, 2023 shares
Subsequent Event [Line Items]
Operating lease option to extend			true
Outstanding stock options \| shares			11,206,435
Subsequent Event [Member] \| Option Exchange Program [Member]
Subsequent Event [Line Items]
Outstanding stock options \| shares	3,500,000
Subsequent Event [Member] \| Option Exchange Program [Member] \| Minimum [Member]
Subsequent Event [Line Items]
Stock options exercise price per share \| $ / shares	$ 35
Options exchange ratio	1.50%
Subsequent Event [Member] \| Option Exchange Program [Member] \| Maximum [Member]
Subsequent Event [Line Items]
Options exchange ratio	5.00%
Subsequent Event [Member] \| Lease Agreements [Member]
Subsequent Event [Line Items]
Area Of Office Space \| ft²		30,567
Lease expire date		Aug. 31, 2024
Expected commencement lease date		Sep. 01, 2024
Initial term		66 months
Monthly base rent for first year \| $		$ 224,158
Monthly base rent increase percentage		3.00%
Operating lease option to extend		The Company has the option to extend the Lease one time for an additional five-year period
Operating lease option to extend additional period		5 years
Subsequent Event [Member] \| Lease Agreements [Member] \| 215 First Street [Member]
Subsequent Event [Line Items]
Area Of Office Space \| ft²		63,017
Subsequent Event [Member] \| Lease Agreements [Member] \| 245 First Street [Member]
Subsequent Event [Line Items]
Area Of Office Space \| ft²		40,419
Subsequent Event [Member] \| Letter of Credit [Member] \| Lease Agreements [Member]
Subsequent Event [Line Items]
Security Deposit \| $		$ 1,400,000
Security deposit amount reduced for third anniversary \| $		$ 1,200,000

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares issued	60,046,676	59,512,158
Common stock, shares outstanding	60,043,643	59,509,125
Treasury stock, shares	3,033	3,033

Income Taxes

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Income Taxes

11.

Income Taxes

Loss before income tax expense consists of the following:


	Year Ended December 31,
	2023			2022			2021
	(in thousands)
Domestic	$	(541,656	)	$	(532,539	)	$	(457,693	)
Foreign		167			(245	)		(199	)
	$	(541,489	)	$	(532,784	)	$	(457,892	)

There is no current or deferred provision for income taxes because the Company has historically incurred and utilized operating losses prior to the year ended December 31, 2023. As of December 31, 2023, the Company continues to maintain a full valuation allowance against its net deferred tax assets. The reported amount of income tax expense for the years differs from the amount that would result from applying domestic federal statutory tax rates to pretax losses primarily because of changes in the valuation allowance.

A reconciliation of the U.S. statutory rate to the Company’s effective tax rate is as follows:


	Year Ended December 31,
	2023			2022			2021
Tax due at statutory rate		21.0	%		21.0	%		21.0	%
State taxes, net of federal		4.1			1.8			1.9
Stock-based compensation		(1.7	)		(1.9	)		(5.2	)
Federal and state tax credits		2.4			2.1			3.5
Change in valuation allowance		(26.2	)		(23.0	)		(20.7	)
Other		0.4			—			(0.5	)
		0.0	%		0.0	%		0.0	%

Significant components of the Company’s net deferred tax assets at December 31, 2023 and 2022 are as follows:


	December 31,
	2023			2022
	(in thousands)
Net operating losses	$	428,785		$	347,880
Tax credits		133,602			118,393
Capitalized research and development expenses		110,690			66,849
Stock-based compensation		53,860			49,916
Accrued expenses		7,018			8,750
Depreciation and amortization		1,456			1,386
Lease liability		1,207			2,803
Right of use asset		(1,042	)		(2,433	)
Other		(382	)		(258	)
Total net deferred tax asset before valuation allowance		735,194			593,286
Valuation allowance		(735,194	)		(593,286	)
	$	—		$	—

On December 22, 2017, the Tax Cuts and Jobs Act (the “TCJA”) was signed into law. Under the TCJA provisions, effective with tax years beginning on or after January 1, 2022, taxpayers can no longer immediately expense qualified research and development expenditures. Taxpayers are now required to capitalize and amortize these costs over five years for research conducted within the United States or 15 years for research conducted abroad.

On August 16, 2022, the Inflation Reduction Act of 2022 (the “IRA”) was signed into law. The IRA introduced new tax provisions, including a 15.0% corporate alternative minimum tax and a 1.0% excise tax on stock repurchases. The

provisions of the IRA are effective for periods after December 31, 2022. The enactment of the IRA did not result in any material adjustments to the Company’s income tax provision or net deferred tax assets as of December 31, 2023.

As of December 31, 2023, the Company had federal net operating loss carryforwards of $1.8 billion, of which $30.4 million begin to expire in 2033 and the remainder do not expire but are subject to 80% limitation. As of December 31, 2023, the Company had state net operating loss carryforwards of $991.2 million that begin to expire in 2033. As of December 31, 2023, the Company had federal and state research and development tax credits carryforwards of $81.4 million and $15.3 million, respectively, which begin to expire in 2031 and 2032, respectively. As of December 31, 2023, the Company had federal orphan drug tax credit carryforwards of $40.1 million, which begin to expire in 2034.

As of December 31, 2023, net deferred tax assets before the valuation allowance increased $141.9 million, primarily due to the capitalization of research and development expenses and the increase of federal and state net operating loss carryforwards due to the loss generated for the year ended December 31, 2023. This increase in net deferred tax assets was offset by a corresponding increase in the valuation allowance.

Management of the Company has evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets, which are comprised principally of federal and state net operating loss, capitalized research and development expenses and tax credit carryforwards. Under the applicable accounting standards, management has considered the Company’s history of losses and concluded that it is more likely than not that the Company will not recognize the benefits of its federal and state deferred tax assets. Accordingly, a full valuation allowance of $735.2 million and $593.3 million has been established at December 31, 2023 and 2022, respectively. The valuation allowance increased by $141.9 million and $122.7 million for the years ended December 31, 2023 and 2022, respectively, primarily due to the capitalization of research and development expenses and generation of net operating losses. The valuation allowance increased by $94.5 million for the year ended December 31, 2021, primarily due to generation of net operating losses.

Pursuant to Section 382 of the Internal Revenue Code of 1986, as amended, (the “Code”), and similar state tax law, certain substantial changes in the Company’s ownership may result in a limitation on the amount of net operating loss and tax credit carryforwards that may be used in future years. Utilization of the net operating loss and tax credit carryforwards may be subject to a substantial annual limitation under Section 382 of the Code, due to ownership change limitations that have occurred previously or that could occur in the future. These ownership changes may limit the amount of net operating loss and tax credit carryforwards that can be utilized annually to offset future taxable income and tax, respectively. The Company completed a Section 382 study through December 31, 2020. Based on the study, the Company underwent two ownership changes for Section 382 purposes which occurred on March 11, 2014 and December 31, 2015. As a result of the ownership changes, the Company’s net operating loss and tax credit carryforwards as of the ownership change dates are subject to limitation under Section 382; however, these limitations are not expected to cause any of the impacted net operating loss and tax credit carryforwards to expire unused. Subsequent ownership changes, as defined by Section 382, may potentially further limit the amount of net operating loss and tax credit carryforwards that could be utilized to offset future taxable income and tax.

The Company applies the authoritative guidance on accounting for and disclosure of uncertainty in tax positions, which requires the Company to determine whether a tax position of the Company is more likely than not to be sustained upon examination, including resolution of any related appeals of litigation processes, based on the technical merits of the position. For tax positions meeting the more likely than not threshold, the tax amount recognized in the financial statements is reduced by the largest benefit that has a greater than fifty percent likelihood of being realized upon the ultimate settlement with the relevant taxing authority.

The following table reconciles the beginning and ending amounts of gross unrecognized tax benefits, excluding interest and penalties, if any, for the years ended December 31, 2023, 2022 and 2021:


	2023		2022		2021
	(in thousands)
Balance as of January 1	$	6,846	$	6,084	$	—
Increases related to current year tax positions		655		697		396
Increases related to prior year tax positions		242		65		5,688
Balance as of December 31	$	7,743	$	6,846	$	6,084

For the years ended December 31, 2023, 2022 and 2021, the increases in unrecognized tax benefits related to current year and prior year tax positions with respect to the Company’s federal and state tax credits.

The Company’s policy is to record interest and penalties related to income taxes as part of the tax provision. As of December 31, 2023 and 2022, the Company had no accrued interest or penalties related to income taxes and no amounts have been recognized in the Company’s statements of operations and comprehensive loss for the years ended December 31, 2023, 2022 and 2021.

The Company files tax returns as prescribed by the tax laws of the jurisdictions in which it operates. In the normal course of business, the Company is subject to examination by federal, state and foreign jurisdictions, where applicable. There are currently no pending tax examinations, and the Company’s tax returns are generally open under statute from 2020 to the present. Tax attributes such as net operating losses and tax credits generated prior to 2020 and utilized in open years may still be adjusted upon examination.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//740/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-14

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-21

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 270
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482526/740-270-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 17
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-17

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482603/740-30-50-2

+ Details

Preferred Stock

12 Months Ended

Dec. 31, 2023

Equity [Abstract]

Preferred Stock

The Board of Directors of the Company (the “Board”) is authorized, without action by the stockholders, to designate and issue up to an aggregate of 5,000,000 shares of preferred stock in one or more series. The Board can designate the rights, preferences and privileges of the shares of each series and any of its qualifications, limitations or restrictions. The Board may authorize the issuance of preferred stock with voting or conversion rights that could adversely affect the voting power or other rights of the holders of common stock. As of December 31, 2023 and 2022, the Company had no shares of preferred stock issued or outstanding and preferred stock is classified within stockholders’ equity.

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 70,992	$ 162,700
Marketable securities	682,192	1,109,794
Prepaid expenses and other current assets	31,825	50,826
Collaboration receivable - related party	$ 83,009	$ 13,660
Accounts Receivable, after Allowance for Credit Loss, Current, Related Party, Type [Extensible Enumeration]	Related Party [Member]	Related Party [Member]
Restricted cash	$ 1,332	$ 0
Total current assets	869,350	1,336,980
Property and equipment, net	1,921	2,898
Restricted cash	0	1,269
Right-of-use operating asset	4,458	10,532
Other long-term assets	6,548	4,770
Total assets	882,277	1,356,449
Current liabilities:
Accounts payable	10,318	18,950
Accrued expenses	67,264	72,666
Operating lease liability, current portion	5,165	7,643
Total current liabilities	82,747	99,259
Operating lease liability, net of current portion	0	4,491
Other liabilities	0	100
Total liabilities	82,747	103,850
Commitments and contingencies (Note 5)
Stockholders’ equity:
Preferred stock, $0.0001 par value per share; 5,000,000 shares authorized at December 31, 2023 and December 31, 2022; no shares issued or outstanding at December 31, 2023 and December 31, 2022
Common stock, $0.0001 par value per share; 120,000,000 shares authorized at December 31, 2023 and December 31, 2022; 60,046,676 and 59,512,158 shares issued at December 31, 2023 and December 31, 2022; 60,043,643 and 59,509,125 shares outstanding at December 31, 2023 and December 31, 2022	6	6
Treasury stock, at cost, 3,033 shares at December 31, 2023 and December 31, 2022	(400)	(400)
Additional paid-in capital	3,370,397	3,291,369
Accumulated deficit	(2,569,659)	(2,028,170)
Accumulated other comprehensive loss	(814)	(10,206)
Total stockholders’ equity	799,530	1,252,599
Total liabilities and stockholders’ equity	$ 882,277	$ 1,356,449

Collaboration Agreements - Summary of Activity and Reimbursement Amounts Related to Collaboration Agreement (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue		$ 86,455	$ 7,686	$ 6,308
Research and development expenses		356,235	326,163	283,166
Selling, general and administrative expenses		274,524	227,699	183,498
Biogen Collaboration Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue					$ 1,100,000
Cost of revenues		504
Research and development expenses		94,325	86,028	84,221
Selling, general and administrative expenses		89,599	51,870	18,425
Reimbursement amounts to (from) collaboration [Abstract]
Collaboration revenue - related party	$ 8,000	(824)
Cost of revenues		504
Selling, general and administrative expenses		16,496	(2,230)	(11,282)
Collaboration Revenue - Related Party [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue		824
Collaboration Revenue - Related Party [Member] \| Biogen Collaboration Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue		824
Research and Development [Member] \| Biogen Collaboration Agreement [Member]
Reimbursement amounts to (from) collaboration [Abstract]
Research and development expenses		$ (76,208)	$ (73,227)	$ (79,848)

Stock-Based Compensation - Summary of Stock-Based Compensation Expense Recognized (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	$ 73,367	$ 61,602	$ 104,629
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	24,813	25,888	49,746
Selling, General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	47,716	35,714	54,883
Restructuring [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	$ 838	$ 0	$ 0

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 35
-Paragraph 1D
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480483/718-10-35-1D

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-Publisher FASB
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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-Section 50
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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Reference 12: http://www.xbrl.org/2003/role/disclosureRef
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Reference 13: http://www.xbrl.org/2003/role/disclosureRef
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Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Leases, Commitments and Contingencies - Schedule of Supplemental Disclosure of Cash Flow Information Related To Operating Leases (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Cash paid for amounts included in the measurement of lease liabilities	$ 7,643	$ 7,468	$ 9,264
Lease asset de-recognized upon lease cancellation			$ 3,733

Balance Sheet Components

12 Months Ended

Dec. 31, 2023

Balance Sheet Related Disclosures [Abstract]

Balance Sheet Components

Property and Equipment, net

The following table summarizes property and equipment, net, as of December 31, 2023 and 2022:


	December 31,			December 31,
	2023			2022
	(in thousands)
Computer hardware and software	$	2,114		$	1,771
Furniture and equipment		1,786			1,714
Leasehold improvements		5,509			5,508
		9,409			8,993
Less: Accumulated depreciation		(7,488	)		(6,095	)
	$	1,921		$	2,898

Depreciation expense for the years ended December 31, 2023, 2022 and 2021 was $1.4 million, $1.1 million and $4.2 million, respectively.

The useful life for computer hardware and software is three years, furniture and equipment is five years, and leasehold improvements is the lesser of the useful life or the term of the respective lease.

Accrued Expenses

The following table summarizes accrued expenses as of December 31, 2023 and 2022:


	December 31,		December 31,
	2023		2022
	(in thousands)
Accrued research and development costs	$	26,040	$	32,565
Restructuring		10,589		—
Employee-related		21,339		29,372
Professional services		8,589		10,172
Other		707		557
	$	67,264	$	72,666

As of December 31, 2023, accrued research and development costs includes $4.3 million of accrued expenses related to cancelling excess purchase commitments for manufacturing as a result of the CRL received from the FDA for zuranolone for the treatment of MDD. During the year ended December 31, 2023, $28.9 million of expenses related to the cancellation of excess purchase commitments were recorded as research and development expense in the consolidated statements of operations and comprehensive loss, net of amounts subject to reimbursement under the Biogen Collaboration Agreement of $14.5 million.

Nature of the Business

12 Months Ended

Dec. 31, 2023

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Nature of the Business

Sage Therapeutics, Inc. (“Sage” or the “Company”) is a biopharmaceutical company with a mission to pioneer solutions to deliver life-changing brain health medicines, so every person can thrive.

The Company’s product ZURZUVAE™ (zuranolone) was approved by the U.S. Food and Drug Administration (the “FDA”) on August 4, 2023 for the treatment of postpartum depression (“PPD”) in adults. ZURZUVAE is a neuroactive steroid that is a positive allosteric modulator of GABAA receptors, targeting both synaptic and extrasynaptic GABAA receptors, and is the first oral, once-daily, 14-day treatment specifically indicated for adults with PPD. ZURZUVAE became commercially available for women with PPD in December 2023. The Company’s product ZULRESSO® (brexanolone) CIV injection is approved in the U.S. for the treatment of PPD in adults. The Company launched ZULRESSO commercially in the U.S. in June 2019. ZULRESSO may only be administered in qualified, medically-supervised healthcare settings. Brexanolone is chemically identical to allopregnanolone, a naturally occurring neuroactive steroid that, like zuranolone, acts as a positive allosteric modulator of GABAA receptors.

Additionally, on August 4, 2023, the FDA issued a complete response letter (“CRL”) related to the Company’s new drug application (“NDA”) for zuranolone for the treatment of major depressive disorder (“MDD”). The CRL stated that the NDA did not provide substantial evidence of effectiveness to support the approval of zuranolone for the treatment of MDD and that one or more additional clinical trials will be needed. The Company and Biogen MA Inc. (“BIMA”) and Biogen International GmbH (collectively with BIMA, “Biogen”) are continuing to seek feedback from the FDA and are evaluating next steps.

The Company has a portfolio of product candidates with a current focus on modulating two critical central nervous system (“CNS”) receptor systems, GABA and NMDA. The GABA receptor family, which is recognized as the major inhibitory neurotransmitter in the CNS, mediates downstream neurologic and bodily function via activation of GABAA receptors. The NMDA-type receptors of the glutamate receptor system are a major excitatory receptor system in the CNS. Dysfunction in these systems is implicated in a broad range of CNS disorders. Alongside the Company’s postpartum depression commercial products, it is targeting diseases and disorders of the brain across its pipeline.

The Company was incorporated under the laws of the State of Delaware on April 16, 2010, and commenced operations on January 19, 2011 as Sterogen Biopharma, Inc. On September 13, 2011, the Company changed its name to Sage Therapeutics, Inc.

Risks and Uncertainties

The Company is subject to risks and uncertainties common to companies in the biopharmaceutical industry, including, but not limited to, the risks associated with developing product candidates at each stage of non-clinical and clinical development; the challenges associated with gaining regulatory approval of such product candidates; the risks associated with the marketing and sale of pharmaceutical products; the potential for development by third parties of new technological innovations that may compete with the Company’s products and product candidates; the dependence on key personnel; the challenges of protecting proprietary technology; the need to comply with government regulations; the high costs of drug development; the uncertainty of being able to secure additional capital when needed to fund operations; and the direct or indirect impacts of the macroeconomic environment and geopolitical events on its development activities, operations and financial condition.

The product candidates developed by the Company require approvals from the FDA or foreign regulatory agencies prior to commercial sales. There can be no assurance that the current and future product candidates of the Company will receive, or that the Company’s current products, ZULRESSO and ZURZUVAE, will maintain, the necessary approvals. If the Company fails to successfully complete clinical development and generate results sufficient to file for regulatory

approval or is denied approval or approval is delayed for any of its product candidates, such occurrences may have a material adverse impact on the Company’s business and its financial condition.

The Company is also subject to additional risks and uncertainties arising from changes to the macroeconomic environment and geopolitical events. U.S. and global financial markets have experienced volatility and disruption due to macroeconomic and geopolitical events such as rising inflation, the risk of a recession and ongoing conflicts in other countries. In addition, if equity and credit markets deteriorate, including as a result of past and potential future bank failures, it may make any future debt or equity financing more difficult to obtain on favorable terms, and potentially more dilutive to its existing stockholders. The Company cannot predict at this time to what extent it and its collaborators, employees, suppliers, contract manufacturers and/or vendors could potentially be negatively impacted by these events.

Going Concern

Under Accounting Standards Update (“ASU”) No. 2014-15, Presentation of Financial Statements—Going Concern (Subtopic 205-40), the Company has the responsibility to evaluate whether conditions and/or events raise substantial doubt about its ability to meet its future financial obligations as they become due within one year after the date that the financial statements are issued. The Company has incurred losses and negative cash flows from operations in each year since its inception, except for net income of $606.1 million for the year ended December 31, 2020, reflecting revenue recognized under a collaboration and license agreement with Biogen (the “Biogen Collaboration Agreement”). As of December 31, 2023, the Company had an accumulated deficit of $2.6 billion. Until such time, if ever, as the Company can generate substantial product revenue and/or collaboration revenue and achieve sustained profitability, the Company expects to finance its cash needs through a combination of equity offerings, debt financings, collaborations, strategic alliances, licensing arrangements and other sources of funding. If the Company is unable to raise additional funds through equity or debt financings or other sources of funding when needed, the Company may be required to delay, limit, reduce or terminate product development or future commercialization efforts or grant rights to develop and market products or product candidates that the Company would otherwise prefer to develop and market itself.

The Company expects that, based on its current operating plans, the Company’s existing cash, cash equivalents and marketable securities will be sufficient to fund its currently planned operations for at least the next 12 months from the filing date of this Annual Report. At some point after that time, the Company anticipates it will require additional financing to fund its future operations. Even if the Company believes it has sufficient funds for its current or future operating plans, the Company may seek to raise additional capital if market conditions are favorable or in light of other strategic considerations.

Restructuring

12 Months Ended

Dec. 31, 2023

Restructuring and Related Activities [Abstract]

Restructuring

13. Restructuring

In August 2023, the Company implemented a strategic corporate reorganization and reprioritization of its pipeline. The reorganization included a reduction of the Company’s workforce by approximately 40%, designed to right-size the organization as the Company worked to achieve sustained growth and support the commercialization of ZURZUVAE to treat women with PPD. During the twelve months ended December 31, 2023, the Company recorded $33.4 million of expense for restructuring, representing all restructuring charges expected to be incurred, primarily for one-time termination benefits to the affected employees, primarily for cash payments of severance, healthcare benefits and outplacement assistance.

The Company expects that substantially all of the accrued restructuring charges as of December 31, 2023 will be paid in cash by March 31, 2024.

The following table summarizes activity related to the restructuring accrual:


	Restructuring accrual
	(in thousands)
Balance as of January 1, 2023	$	—
Restructuring expenses incurred		33,386
Cash paid		(19,163	)
Non-cash activity		(3,634	)
Balance as of December 31, 2023	$	10,589

Leases, Commitments and Contingencies - Schedule of Minimum Lease Payments (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Lessee Lease Description [Line Items]
Present value of operating lease liabilities	$ 5,165	$ 12,134
ASU Topic (842) [Member]
Lessee Lease Description [Line Items]
2024	5,316
Total lease payments	5,316
Less imputed interest	(151)
Present value of operating lease liabilities	$ 5,165

Leases, Commitments and Contingencies - CyDex License Agreement - Additional Information (Detail) - USD ($)	12 Months Ended				100 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2023
Commitments And Contingencies [Line Items]
Research and development expense	$ 356,235,000	$ 326,163,000	$ 283,166,000
CyDex License Agreement [Member]
Commitments And Contingencies [Line Items]
Research and development expense					$ 1,000,000
CyDex License Agreement [Member] \| First and Second Clinical Development Milestones [Member] \| Brexanolone [Member] \| Maximum [Member]
Commitments And Contingencies [Line Items]
Expected milestone payments	800,000				800,000
CyDex License Agreement [Member] \| First and Second Regulatory Milestones [Member] \| Brexanolone [Member] \| Maximum [Member]
Commitments And Contingencies [Line Items]
Expected milestone payments	3,800,000				3,800,000
CyDex License Agreement [Member] \| Third and Fourth Clinical Development Milestones [Member] \| Brexanolone [Member] \| Maximum [Member]
Commitments And Contingencies [Line Items]
Expected milestone payments	1,300,000				1,300,000
CyDex License Agreement [Member] \| Third and Fourth Regulatory Milestones [Member] \| Brexanolone [Member] \| Maximum [Member]
Commitments And Contingencies [Line Items]
Expected milestone payments	8,500,000				8,500,000
CyDex License Agreement [Member] \| Clinical Development [Member] \| SAGE-689 [Member]
Commitments And Contingencies [Line Items]
Research and development expense			$ 100,000	$ 1,300,000
CyDex License Agreement [Member] \| Clinical Development [Member] \| SAGE-689 [Member] \| Maximum [Member]
Commitments And Contingencies [Line Items]
Expected milestone payments	800,000				800,000
CyDex License Agreement [Member] \| Regulatory Milestones [Member] \| Brexanolone [Member]
Commitments And Contingencies [Line Items]
Milestone payments related to intangible assets	0	$ 0
CyDex License Agreement [Member] \| Regulatory Milestones [Member] \| SAGE-689 [Member] \| Maximum [Member]
Commitments And Contingencies [Line Items]
Expected milestone payments	1,800,000				1,800,000
CyDex License Agreement [Member] \| Clinical Development and Regulatory Milestones [Member]
Commitments And Contingencies [Line Items]
Research and development expense related to milestone expense					3,600,000
Milestone payments					3,600,000
Intangible asset related to milestone	$ 3,000,000.0				$ 3,000,000.0

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pay vs Performance Disclosure
Net Income (Loss)	$ (541,489)	$ (532,784)	$ (457,892)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

+ Details

Restructuring (Tables)

12 Months Ended

Dec. 31, 2023

Restructuring and Related Activities [Abstract]

Summary of Restructuring Activity

The following table summarizes activity related to the restructuring accrual:


	Restructuring accrual
	(in thousands)
Balance as of January 1, 2023	$	—
Restructuring expenses incurred		33,386
Cash paid		(19,163	)
Non-cash activity		(3,634	)
Balance as of December 31, 2023	$	10,589

Income Taxes - Summary of Income (Loss) Before Income Tax Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Domestic	$ (541,656)	$ (532,539)	$ (457,693)
Foreign	167	(245)	(199)
Net income (loss) before income tax expense	$ (541,489)	$ (532,784)	$ (457,892)

- Definition

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(11))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483586/944-220-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 30
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-30

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 31
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-31

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 235
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-05(b)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479557/942-235-S99-1

Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 25
-Paragraph 1
-SubTopic 20
-Topic 940
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481913/940-20-25-1

Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(10))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(15))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483589/942-220-S99-1

+ Details

Stock-Based Compensation - Summary of Weighted Average Assumptions Used to Compute Fair Value of Option Granted (Detail)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-Based Payment Arrangement [Abstract]
Expected dividend yield	0.00%	0.00%	0.00%
Expected volatility	72.00%	73.00%	76.00%
Risk-free interest rate	3.85%	2.49%	0.63%
Expected term	6 years 3 days	6 years 10 days	5 years 11 months 1 day

Employee Benefit Plan	12 Months Ended
Employee Benefit Plan	Dec. 31, 2023
Postemployment Benefits [Abstract]
Employee Benefit Plan	12. Employee Benefit Plan The Company maintains a 401(k) profit sharing plan (the “401(k) Plan”) for its employees. Each employee may elect to contribute a portion of his or her compensation to the 401(k) Plan, subject to annual limits established by the Internal Revenue Service. For the years ended December 31, 2023, 2022 and 2021, the Company matched 50% of eligible contributions to the 401(k) Plan up to 6% of employee contributions. For the years ended December 31, 2023, 2022 and 2021 the Company contributed $3.9 million, $3.0 million and $1.8 million, respectively, to the 401(k) Plan.

Stock-Based Compensation - Summary of Stock-Based Compensation Expense by Award Type (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	$ 73,367	$ 61,602	$ 104,629
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	47,695	54,971	78,516
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	24,424	5,587	25,375
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	$ 1,248	$ 1,044	$ 738

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

+ Details

Balance Sheet Components - Summary of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 9,409	$ 8,993
Less: Accumulated depreciation	(7,488)	(6,095)
Property and equipment, net	1,921	2,898
Computer Hardware and Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	2,114	1,771
Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,786	1,714
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 5,509	$ 5,508

Income Taxes - Additional Information (Detail) - USD ($)		12 Months Ended
	Aug. 16, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Line Items]
Current tax expense		$ 0
Research and development expense		356,235,000	$ 326,163,000	$ 283,166,000
Deferred tax expense		0
Inflation reduction of corporate alternative minimum tax	15.00%
Inflation reduction of excise tax on stock repurchases	1.00%
Federal operating loss carryforwards		$ 1,800,000,000
Federal net operating loss carryforwards, limitation percentage		80.00%
Federal orphan drug tax credit carry forwards		$ 40,100,000
Tax credit carry forwards expiration period		2034
Change in amount of deferred tax assets		$ 141,900,000
Valuation allowance		735,194,000	593,286,000
Valuation allowance, increase (decrease), amount		141,900,000	122,700,000	94,500,000
Accrued interest or penalties related to uncertain tax positions		0	0
Uncertain tax positions		0	$ 0	$ 0
Begin to Expire 2033 [Member]
Income Tax Disclosure [Line Items]
Federal operating loss carryforwards		$ 30,400,000
Federal net operating loss carryforwards expiration year		2033
State operating loss carryforwards		$ 991,200,000
State net operating loss carryforwards expiration year		2033
Domestic Tax Authority [Member]
Income Tax Disclosure [Line Items]
Research and development tax credits carryforwards		$ 81,400,000
Research and development tax credits carryforwards expiration year		2031
State and Local Jurisdiction [Member]
Income Tax Disclosure [Line Items]
Research and development tax credits carryforwards		$ 15,300,000
Research and development tax credits carryforwards expiration year		2032

Restructuring - Schedule of Restructuring Accrual (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($)
Restructuring Reserve [Roll Forward]
Restructuring accrual, Balance as of January 1, 2023	$ 0
Restructuring	33,386
Cash paid	(19,163)
Non-cash activity	(3,634)
Restructuring accrual, Balance as of December 31, 2023	$ 10,589

Fair Value Measurements - Summary of Gross Unrealized Gains and Losses of Marketable Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 683,006	$ 1,120,000
Gross Unrealized Gains	437	44
Gross Unrealized Losses	(1,251)	(10,250)
Fair Value	682,192	1,109,794
U.S. Government Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	167,165	307,173
Gross Unrealized Gains	107
Gross Unrealized Losses	(347)	(4,262)
Fair Value	166,925	302,911
U.S. Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	210,491	358,019
Gross Unrealized Gains	191	6
Gross Unrealized Losses	(484)	(3,530)
Fair Value	210,198	354,495
International Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	97,698	128,374
Gross Unrealized Gains	99	7
Gross Unrealized Losses	(122)	(1,133)
Fair Value	97,675	127,248
U.S. Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	23,360	63,234
Gross Unrealized Gains	11
Gross Unrealized Losses	(1)	(120)
Fair Value	23,370	63,114
International Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	46,935	133,338
Gross Unrealized Gains	3
Gross Unrealized Losses	(38)	(175)
Fair Value	46,900	133,163
U.S. Certificates of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	8,830	15,613
Fair Value	8,830	15,613
U.S. Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	128,527	114,249
Gross Unrealized Gains	26	31
Gross Unrealized Losses	(259)	(1,030)
Fair Value	$ 128,294	$ 113,250

Stock-Based Compensation - Additional Information (Detail)		12 Months Ended
	Jan. 01, 2023 shares	Dec. 31, 2023 USD ($) Milestone $ / shares shares	Dec. 31, 2022 USD ($) Milestone $ / shares shares	Dec. 31, 2021 USD ($) Milestone $ / shares shares	Jun. 16, 2023 shares	Jun. 16, 2022 shares	Sep. 20, 2018 shares	Jul. 02, 2014 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation granted under plan vested period		4 years
Share based compensation, vest period		1 year
Share based compensation, term of plan		10 years
Total number of shares outstanding \| shares		11,206,435
Common stock available for issuance under stock option plan \| shares		7,407,863
Stock-based compensation expense \| $		$ 73,367,000	$ 61,602,000	$ 104,629,000
Stock-based compensation expense tied to total stockholder return \| $		$ 73,367,000	$ 61,602,000	$ 104,629,000
Weighted average grant date fair value per share \| $ / shares		$ 29.53	$ 25.96	$ 51.87
Share option, weighted-average forfeiture rates		16.60%	19.20%	16.70%
Restructuring [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense \| $		$ 838,000	$ 0	$ 0
Time Based Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units vested \| shares		51,851	366,014	113,941
Fair value of restricted stock units vested \| $		$ 1,800,000	$ 12,400,000	$ 8,800,000
Outstanding and unvested restricted stock units \| shares		1,662,363
Total unrecognized stock-based compensation expense \| $		$ 40,200,000
Weighted average period of unrecognized compensation costs		1 year 8 months 15 days
Performance Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units granted \| shares		905,012	705,380	531,176
Fair value of restricted stock units vested \| $			$ 0
Stock-based compensation expense \| $		$ 0	$ 0	$ 0
Stock-based compensation expense tied to total stockholder return \| $		$ 700,000
Outstanding and unvested restricted stock units \| shares		1,426,031
Total unrecognized stock-based compensation expense \| $		$ 65,800,000
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted \| shares		964,253
Total number of shares outstanding \| shares		8,118,041	7,788,350
Stock-based compensation expense \| $		$ 47,695,000	$ 54,971,000	78,516,000
Total unrecognized stock-based compensation expense \| $		$ 42,700,000
Weighted average period of unrecognized compensation costs		2 years 9 months 3 days
Intrinsic value of options exercised \| $		$ 1,900,000	4,400,000	9,000,000
Performance-Based Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense \| $		$ 0	$ 0	$ 0
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted \| shares		0	0
Total unrecognized stock-based compensation expense \| $		$ 24,900,000
Number of shares outstanding and unvested stock options \| shares		455,000
Performance Shares [Member] \| Chief Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted \| shares				650,000
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units granted \| shares		2,639,729
Stock-based compensation expense \| $		$ 24,424,000	$ 5,587,000	$ 25,375,000
Outstanding and unvested restricted stock units \| shares		3,088,394	1,415,481
Restricted Stock Units Vest One Year Anniversary [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units vesting percentage		25.00%
2011 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted \| shares		0
2014 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares annual increase added to plan \| shares	2,380,365
2014 Plan [Member] \| Performance Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of restricted stock units vested \| $		$ 9,600,000		9,500,000
Stock-based compensation expense \| $		$ 14,300,000		$ 16,600,000
Regulatory development Milestone achieved \| Milestone		3		2
2014 Plan [Member] \| Performance-Based Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense \| $		$ 10,700,000
Regulatory development Milestone achieved \| Milestone		1	0	0
2014 Plan [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of increase on outstanding shares of Common stock			4.00%
2016 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total number of shares reserved for issuance \| shares							1,200,000
2014 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total number of shares reserved for issuance \| shares					500,000	300,000		282,000
Number of shares issued under the plan \| shares		445,920
Accrued expenses \| $		$ 400,000
Total number of shares available for issuance \| shares		636,080

Fair Value Measurements - Summary of Company's Cash Equivalents and Marketable Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	$ 68,547	$ 161,185
Total marketable securities	682,192	1,109,794
Total cash equivalents and marketable securities	750,739	1,270,979
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	59,852	161,185
Total cash equivalents and marketable securities	59,852	161,185
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	8,695
Total marketable securities	682,192	1,109,794
Total cash equivalents and marketable securities	690,887	1,109,794
Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	59,852	161,185
Money Market Funds [Member] \| Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	59,852	161,185
International Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	97,675	127,248
International Corporate Bonds [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	97,675	127,248
U.S. Government Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	8,695
Total marketable securities	166,925	302,911
U.S. Government Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	8,695
Total marketable securities	166,925	302,911
U.S. Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	210,198	354,495
U.S. Corporate Bonds [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	210,198	354,495
U.S. Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	23,370	63,114
U.S. Commercial Paper [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	23,370	63,114
International Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	46,900	133,163
International Commercial Paper [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	46,900	133,163
U.S. Certificates of Deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	8,830	15,613
U.S. Certificates of Deposit [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	8,830	15,613
U.S. Municipal Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	128,294	113,250
U.S. Municipal Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	$ 128,294	$ 113,250

Leases, Commitments and Contingencies - Schedule of Weighted Average Remaining Lease Term and Weighted Average Discount Rate of Our Operating Leases (Detail)	Dec. 31, 2023	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Weighted average remaining lease term in years	8 months 8 days	1 year 8 months 4 days
Weighted average discount rate	7.50%	7.50%