0000950170-24-047919 | 10-Q | XBRL Viewer

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Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2024	Dec. 31, 2023
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	60,185,064	60,046,676
Common stock, shares outstanding	60,182,031	60,043,643
Treasury stock, shares	3,033	3,033

Commitments and Contingencies	3 Months Ended
Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	6. Commitments and Contingencies Operating Leases The Company leases office space and certain equipment. All of the leases recorded on the condensed consolidated balance sheets are operating leases. The Company’s active 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. The Company leases office space in two multi-tenant buildings in Cambridge, Massachusetts, consisting of 63,017 square feet in the first building, the Company’s current headquarters at 215 First Street, Cambridge, Massachusetts, under an operating lease that will expire on August 31, 2024 (the “First Building Lease”) and 40,419 square feet in the second building, at 245 First Street, Cambridge, Massachusetts, under an operating lease that will expire on August 31, 2024 (the “Second Building Lease”); 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. In January 2024, the Company entered into a lease agreement (the “New Lease”) with 55 Cambridge Parkway, LLC, a Delaware limited liability company (the “Landlord”), pursuant to which the Company will lease approximately 30,567 square feet of office space located at 55 Cambridge Parkway, Cambridge, Massachusetts (the “New Premises”). The Company intends to relocate its corporate headquarters to the New Premises upon the expiration on August 31, 2024 of the First Building Lease and the Second Building Lease, each in accordance with its terms. The term of the New Lease will commence on the later of (1) September 1, 2024, or (2) the date on which improvements to the New Premises are, or are deemed to be, substantially completed (the “Commencement Date”). The Company’s obligation for the payment of rent for the New Premises begins six months after the Commencement Date (the “Rent Commencement Date”). As of March 31, 2024, a lease commencement date in accordance with ASC 842, Leases, had not occurred, as such no right-of-use asset or lease liability has been recorded. The New Lease has an initial term of approximately sixty-six months, measured from the Commencement Date (the “New Lease Term”). The monthly base rent due under the New Lease shall initially 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 of the New Lease Term. The Company has the option to extend the New Lease one time for an additional five-year period, subject to the terms therein. The Lease also provides for a construction allowance (the “Allowance”) not to exceed approximately $3.4 million to be applied to the construction costs of the New Premises. The Allowance must be used on or before the one-year anniversary of the Commencement Date or will be deemed forfeited with no further obligation by the Landlord. In connection with its entry into the New Lease, and as a security deposit, the Company has provided the Landlord a letter of credit in the amount of approximately $1.4 million during three months ended March 31, 2024, 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 New Lease upon customary events of default. 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 March 31, 2024, 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 March 31, 2024, 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 three months ended March 31, 2024 and 2023, 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 March 31, 2024, 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 three months ended March 31, 2024 and 2023, the Company did not record any expense or make any milestone payments under the license agreements with the Regents.

Commitments and Contingencies

3 Months Ended

Mar. 31, 2024

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

6. Commitments and Contingencies

Operating Leases

The Company leases office space and certain equipment. All of the leases recorded on the condensed consolidated balance sheets are operating leases. The Company’s active 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.

The Company leases office space in two multi-tenant buildings in Cambridge, Massachusetts, consisting of 63,017 square feet in the first building, the Company’s current headquarters at 215 First Street, Cambridge, Massachusetts, under an operating lease that will expire on August 31, 2024 (the “First Building Lease”) and 40,419 square feet in the second building, at 245 First Street, Cambridge, Massachusetts, under an operating lease that will expire on August 31, 2024 (the “Second Building Lease”); 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.

In January 2024, the Company entered into a lease agreement (the “New Lease”) with 55 Cambridge Parkway, LLC, a Delaware limited liability company (the “Landlord”), pursuant to which the Company will lease approximately 30,567 square feet of office space located at 55 Cambridge Parkway, Cambridge, Massachusetts (the “New Premises”). The Company intends to relocate its corporate headquarters to the New Premises upon the expiration on August 31, 2024 of the First Building Lease and the Second Building Lease, each in accordance with its terms. The term of the New Lease will commence on the later of (1) September 1, 2024, or (2) the date on which improvements to the New Premises are, or are deemed to be, substantially completed (the “Commencement Date”). The Company’s obligation for the payment of rent for the New Premises begins six months after the Commencement Date (the “Rent Commencement Date”). As of March 31, 2024, a lease commencement date in accordance with ASC 842, Leases, had not occurred, as such no right-of-use asset or lease liability has been recorded. The New Lease has an initial term of approximately sixty-six months, measured from the Commencement Date (the “New Lease Term”). The monthly base rent due under the New Lease shall initially 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 of the New Lease Term. The Company has the option to extend the New Lease one time for an additional five-year period, subject to the terms therein. The Lease also provides for a construction allowance (the “Allowance”) not to exceed approximately $3.4 million to be applied to the construction costs of the New Premises. The Allowance must be used on or before the one-year anniversary of the Commencement Date or will be deemed forfeited with no further obligation by the Landlord.

In connection with its entry into the New Lease, and as a security deposit, the Company has provided the Landlord a letter of credit in the amount of approximately $1.4 million during three months ended March 31, 2024, 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 New Lease upon customary events of default.

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 March 31, 2024, 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 March 31, 2024, 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 three months ended March 31, 2024 and 2023, 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 March 31, 2024, 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 three months ended March 31, 2024 and 2023, the Company did not record any expense or make any milestone payments under the license agreements with the Regents.

Restructuring

3 Months Ended

Mar. 31, 2024

Restructuring and Related Activities [Abstract]

Restructuring

11. 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 works to achieve sustained growth and support the commercialization of ZURZUVAE to treat women with PPD.

As of March 31, 2024, the Company has paid substantially all of the accrued restructuring charges. Total restructuring charges incurred to date are $32.8 million which is the total expected amount to be incurred.

The following table summarizes activity related to the restructuring accrual during the three months ended March 31, 2024:


	Restructuring Accrual
	(in thousands)
Balance as of December 31, 2023	$	10,589
Restructuring expenses incurred		(597	)
Cash paid		(7,424	)
Non-cash activity		—
Balance as of March 31, 2024	$	2,568

Nature of the Business - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Mar. 31, 2024	Dec. 31, 2023
Nature Of Business [Line Items]
Accumulated deficit		$ 2,678,142	$ 2,569,659
Net income from up-front	$ 606,100
Redeemable Convertible Preferred Stock [Member] \| Convertible Notes [Member] \| Initial Public Offering [Member]
Nature Of Business [Line Items]
Accumulated deficit		$ 2,700,000

- Definition

Amount of accumulated undistributed earnings (deficit).

+ References + Details

Investments - Additional Information (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Debt Securities, Available-for-Sale [Line Items]
Accrued Interest Receivable Written Off	$ 0	$ 0
Impairment of assets	$ 0		$ 0
US Treasury Bond Securities \| U.S. Corporate Bonds [Member] \| Maximum [Member]
Debt Securities, Available-for-Sale [Line Items]
Marketable securities, remaining contractual maturities	1 year		1 year
US Treasury Bond Securities \| Corporate Bonds and Municipal Securities [Member]
Debt Securities, Available-for-Sale [Line Items]
Marketable securities fair value held to maturity	$ 46,300,000		$ 110,300,000
US Treasury Bond Securities \| Corporate Bonds and Municipal Securities [Member] \| Maximum [Member]
Debt Securities, Available-for-Sale [Line Items]
Marketable Securities Maturity Period	2 years		2 years
US Treasury Bond Securities \| Corporate Bonds and Municipal Securities [Member] \| Minimum [Member]
Debt Securities, Available-for-Sale [Line Items]
Marketable Securities Maturity Period	1 year		1 year
Prepaid Expenses and Other Current Assets [Member]
Debt Securities, Available-for-Sale [Line Items]
Accrued interest receivable	$ 3,600,000		$ 4,200,000

Investments - Summary of Gross Unrealized Gains and Losses and Credit Losses (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 545,147	$ 683,006
Gross Unrealized Gains	92	437
Gross Unrealized Losses	(879)	(1,251)
Fair Value	544,360	682,192
U.S. Government Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	136,948	167,165
Gross Unrealized Gains	16	107
Gross Unrealized Losses	(239)	(347)
Fair Value	136,725	166,925
U.S. Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	182,247	210,491
Gross Unrealized Gains	42	191
Gross Unrealized Losses	(340)	(484)
Fair Value	181,949	210,198
International Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	83,974	97,698
Gross Unrealized Gains	23	99
Gross Unrealized Losses	(136)	(122)
Fair Value	83,861	97,675
U.S. Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	30,349	23,360
Gross Unrealized Gains	9	11
Gross Unrealized Losses	(1)	(1)
Fair Value	30,357	23,370
International Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	45,064	46,935
Gross Unrealized Gains	2	3
Gross Unrealized Losses	(7)	(38)
Fair Value	45,059	46,900
U.S. Certificates of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,303	8,830
Fair Value	1,303	8,830
U.S. Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	65,262	128,527
Gross Unrealized Gains		26
Gross Unrealized Losses	(156)	(259)
Fair Value	$ 65,106	$ 128,294

Collaboration Agreements - Summary of Activity and Reimbursement Amounts Related to Collaboration Agreement (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Dec. 31, 2020
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue	$ 7,902	$ 3,294
Research and development expenses	71,734	92,826
Selling, general and administrative expenses	52,574	65,708
Collaboration Revenue - Related Party [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue	6,212
Biogen Collaboration Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue				$ 1,100,000
Cost of revenues	1,201
Research and development expenses	7,031	22,171
Selling, general and administrative expenses	12,983	18,963
Reimbursement amounts to (from) collaboration [Abstract]
Collaboration revenue - related party	(6,212)		$ 8,000
Cost of revenues	(562)
Selling, general and administrative expenses	2,306	3,034
Biogen Collaboration Agreement [Member] \| Research and Development [Member]
Reimbursement amounts to (from) collaboration [Abstract]
Research and development expenses	(5,657)	$ (17,282)
Biogen Collaboration Agreement [Member] \| Collaboration Revenue - Related Party [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue	$ 6,212

Net Loss Per Share

3 Months Ended

Mar. 31, 2024

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 three months ended March 31, 2024 and 2023:


	Three Months Ended March 31,
	2024			2023
Basic net loss per share:
Numerator:
Net loss (in thousands)	$	(108,483	)	$	(146,828	)
Denominator:
Weighted average common stock outstanding - basic and diluted		60,136,198			59,674,127
Net loss per share - basic and diluted	$	(1.80	)	$	(2.46	)

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 three months ended March 31, 2024 and 2023:


	Three Months Ended March 31,
	2024		2023
Stock options		6,520,634		7,733,310
Restricted stock units		2,399,564		470,891
Employee stock purchase plan		52,975		46,846
		8,973,173		8,251,047

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.

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Total revenue	$ 7,902	$ 3,294
Operating costs and expenses:
Cost of revenues	1,269	230
Research and development	71,734	92,826
Selling, general and administrative	52,574	65,708
Total operating costs and expenses	125,577	158,764
Loss from operations	(117,675)	(155,470)
Interest income, net	9,204	8,830
Other expense, net	(12)	(188)
Net loss	$ (108,483)	$ (146,828)
Net loss per share - basic	$ (1.8)	$ (2.46)
Net loss per share - diluted	$ (1.8)	$ (2.46)
Weighted average number of common shares outstanding— basic	60,136,198	59,674,127
Weighted average number of common shares outstanding— diluted	60,136,198	59,674,127
Comprehensive loss:
Net loss	$ (108,483)	$ (146,828)
Other comprehensive items:
Unrealized gain on marketable securities	27	5,118
Total comprehensive loss	(108,456)	(141,710)
Product Revenue [Member]
Total revenue	1,690	$ 3,294
Collaboration Revenue - Related Party [Member]
Total revenue	$ 6,212

Common Stock - Additional Information (Details) - USD ($)		3 Months Ended	12 Months Ended
	Nov. 07, 2023	Mar. 31, 2024	Dec. 31, 2023
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
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.
Dividends declared		$ 0	$ 0
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%

Collaboration Agreements

3 Months Ended

Mar. 31, 2024

Shionogi Collaboration Agreement [Member]

Collaboration Agreements

7. 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 active pharmaceutical ingredient (“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 excludes the $90.0 million upfront payment, 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 condensed consolidated statements of operations and comprehensive loss. For the three months ended March 31, 2024 and 2023 the Company recognized no collaboration revenue from 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. Payment of the $75.0 million milestone was received during January 2024. During the three months ended March 31, 2024 and 2023, 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 condensed consolidated statement of operations and comprehensive loss, 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 products and SAGE-324 products, as reflected in our condensed consolidated statement of operations and comprehensive loss:


	Three Months Ended March 31,
	2024		2023
	(in thousands)
Collaboration revenue - related party	$	6,212	$	—
Cost of revenues		1,201		—
Research and development expenses		7,031		22,171
Selling, general and administrative expenses		12,983		18,963

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:


	Three Months Ended March 31,
	2024			2023
	(in thousands)
Collaboration revenue - related party	$	(6,212	)	$	—
Cost of revenues		(562	)		—
Research and development expenses		(5,657	)		(17,282	)
Selling, general and administrative expenses		2,306			3,034

As of March 31, 2024, the Company recorded a collaboration receivable - related party of $10.5 million all related to net reimbursement for the amounts due for the three months ended March 31, 2024. 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 three months ended March 31, 2024, no payments were made to Biogen and the Company received $82.6 million from Biogen for the amounts due for the three months ended December 31, 2023. During the three months ended March 31, 2023, no payments were made to Biogen and the Company received $12.9 million from Biogen for the amounts due for the three months ended December 31, 2022.

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.

Commitments and Contingencies - CyDex License Agreement - Additional Information (Detail) - USD ($)	3 Months Ended		106 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024
Commitments And Contingencies [Line Items]
Research and development expense	$ 71,734,000	$ 92,826,000
CyDex License Agreement [Member]
Commitments And Contingencies [Line Items]
Research and development expense			$ 1,000,000.0
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] \| 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	3 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (108,483)	$ (146,828)

- 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

Net Loss Per Share - Summary of Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Numerator:
Net loss	$ (108,483)	$ (146,828)
Denominator:
Weighted average common stock outstanding - basic	60,136,198	59,674,127
Weighted average common stock outstanding - diluted	60,136,198	59,674,127
Net loss per share - basic	$ (1.8)	$ (2.46)
Net loss per share - diluted	$ (1.8)	$ (2.46)

- 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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+ Details

- Definition

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

+ References

+ Details

Investments (Tables)

3 Months Ended

Mar. 31, 2024

Investments, Debt and Equity Securities [Abstract]

Summary of Gross Unrealized Gains and Losses and credit losses

The following tables summarize the fair value and amortized cost of the Company’s available-for-sale securities by major security type including gross unrealized gains and losses and credit losses as of March 31, 2024 and December 31, 2023:


	March 31, 2024
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Credit Losses		Fair Value
	(in thousands)
Assets:
U.S. government securities	$	136,948	$	16	$	(239	)	$	—	$	136,725
U.S. corporate bonds		182,247		42		(340	)		—		181,949
International corporate bonds		83,974		23		(136	)		—		83,861
U.S. commercial paper		30,349		9		(1	)		—		30,357
International commercial paper		45,064		2		(7	)		—		45,059
U.S. certificates of deposit		1,303		—		—			—		1,303
U.S. municipal securities		65,262		—		(156	)		—		65,106
	$	545,147	$	92	$	(879	)	$	—	$	544,360


	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

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

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 March 31, 2024 and December 31, 2023:


	March 31, 2024
	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	$	100,615	$	(141	)	$	21,462	$	(98	)	$	122,077	$	(239	)
U.S. corporate bonds		115,218		(283	)		15,430		(57	)		130,648		(340	)
International corporate bonds		42,335		(114	)		5,718		(22	)		48,053		(136	)
U.S. commercial paper		4,914		(1	)		—		—			4,914		(1	)
International commercial paper		18,766		(7	)		—		—			18,766		(7	)
U.S. municipal securities		50,157		(104	)		14,948		(52	)		65,105		(156	)
	$	332,005	$	(650	)	$	57,558	$	(229	)	$	389,563	$	(879	)


	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	)

- 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).

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+ Details

Fair Value Measurements - Summary of Company's Cash Equivalents and Marketable Securities (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	$ 171,402	$ 68,547
Total marketable securities	544,360	682,192
Total cash equivalents and marketable securities	715,762	750,739
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	159,464	59,852
Total cash equivalents and marketable securities	159,464	59,852
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	11,938	8,695
Total marketable securities	544,360	682,192
Total cash equivalents and marketable securities	556,298	690,887
Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	159,464	59,852
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	159,464	59,852
International Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	4,962
Total marketable securities	83,861	97,675
International Corporate Bonds [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	4,962
Total marketable securities	83,861	97,675
U.S. Government Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	4,983	8,695
Total marketable securities	136,725	166,925
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	4,983	8,695
Total marketable securities	136,725	166,925
U.S. Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	1,993
Total marketable securities	181,949	210,198
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 cash equivalents	1,993
Total marketable securities	181,949	210,198
U.S. Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	30,357	23,370
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	30,357	23,370
International Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	45,059	46,900
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	45,059	46,900
U.S. Certificates of Deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	1,303	8,830
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	1,303	8,830
U.S. Municipal Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	65,106	128,294
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	$ 65,106	$ 128,294

Summary of Significant Accounting Policies (Policies)	3 Months Ended
Summary of Significant Accounting Policies (Policies)	Mar. 31, 2024
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 March 31, 2024, the Company had an accumulated deficit of $2.7 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 these unaudited interim condensed consolidated financial statements (“condensed consolidated financial statements”). 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 condensed consolidated financial statements of the Company included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission. Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) have been condensed or omitted from this report, as is permitted by such rules and regulations. Accordingly, these condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements as of and for the year ended December 31, 2023, included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023. The condensed consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements. In the opinion of the Company’s management, the accompanying condensed consolidated financial statements contain all adjustments, consisting of only normal recurring adjustments, necessary for a fair statement of its financial position as of March 31, 2024, its results of operations and comprehensive loss for the three months ended March 31, 2024 and 2023, its cash flows for the three months ended March 31, 2024 and 2023, and its statements of changes in stockholders’ equity for the three months ended March 31, 2024 and 2023. The consolidated balance sheet at December 31, 2023 was derived from audited financial statements, but does not include all disclosures required by GAAP. The results for the three months ended March 31, 2024 are not necessarily indicative of the results for the year ending December 31, 2024, or for any future period.
Principles of Consolidation	Principles of Consolidation The condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries as disclosed in Note 2, Summary of Significant Accounting Policies, within the “Notes to Consolidated Financial Statements” accompanying its Annual Report on Form 10-K for the year ended December 31, 2023. Intercompany accounts and transactions have been eliminated.
Use of Estimates	Use of Estimates The preparation of condensed 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 condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting period.
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.
Revenue Recognition	Revenue Recognition Under Accounting Standards Codification (“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 condensed 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 condensed 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 March 31, 2024, as customer invoicing generally occurs before or at the time of revenue recognition. The Company did not have any contract liabilities at March 31, 2024, 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 condensed consolidated balance sheets. As of March 31, 2024 and December 31, 2023, 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 condensed 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 condensed 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 condensed 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 condensed consolidated balance sheets. Product returns have not been 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 SSP 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 7, 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 condensed 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 7, Collaboration Agreements.
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 March 31, 2024 and December 31, 2023 were carried at fair value, determined according to the fair value hierarchy; see Note 3, Fair Value Measurements. The carrying amounts reflected in the condensed 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 March 31, 2024 and December 31, 2023, respectively.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements Accounting standards that have been issued or proposed by the Financial Accounting Standards Board 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 condensed consolidated financial statements upon adoption.

Nature of the Business

3 Months Ended

Mar. 31, 2024

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 individuals 15 years old and older. 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 March 31, 2024, the Company had an accumulated deficit of $2.7 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 these unaudited interim condensed consolidated financial statements (“condensed consolidated financial statements”). 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.

Common Stock

3 Months Ended

Mar. 31, 2024

Text Block [Abstract]

Common Stock

8. Common Stock

As of March 31, 2024 and December 31, 2023, the Company had 120,000,000 authorized shares of common stock, par value $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 of Directors of the Company (the “Board”), if any. As of March 31, 2024 and December 31, 2023, no dividends have been declared.

As of March 31, 2024, 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 March 31, 2024 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 the 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 ATM Offering upon notice to the other parties and subject to other conditions. Cowen will act as sales agent on a commercially reasonable efforts basis consistent with its normal trading and sales practices, applicable state and federal laws, rules and regulations, and the rules of The Nasdaq Global Market.

The Company has agreed to pay Cowen commission for its service in acting as agent in the sale of the Shares in the amount of up to 3.0% of the gross proceeds from the sale of the Shares pursuant to the Sales Agreement

During the three months ended March 31, 2024, the Company did not sell any shares under the Sales Agreement.

Accrued Expenses (Tables)

3 Months Ended

Mar. 31, 2024

Payables and Accruals [Abstract]

Summary of Accrued Expenses

The following table summarizes accrued expenses as of March 31, 2024 and December 31, 2023:


	March 31,		December 31,
	2024		2023
	(in thousands)
Accrued research and development costs	$	30,627	$	26,040
Restructuring		2,568		10,589
Employee-related		7,092		21,339
Professional services		11,178		8,589
Other		549		707
	$	52,014	$	67,264

Investments

3 Months Ended

Mar. 31, 2024

Investments, Debt and Equity Securities [Abstract]

Investments

4. Investments


	March 31, 2024
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Credit Losses		Fair Value
	(in thousands)
Assets:
U.S. government securities	$	136,948	$	16	$	(239	)	$	—	$	136,725
U.S. corporate bonds		182,247		42		(340	)		—		181,949
International corporate bonds		83,974		23		(136	)		—		83,861
U.S. commercial paper		30,349		9		(1	)		—		30,357
International commercial paper		45,064		2		(7	)		—		45,059
U.S. certificates of deposit		1,303		—		—			—		1,303
U.S. municipal securities		65,262		—		(156	)		—		65,106
	$	545,147	$	92	$	(879	)	$	—	$	544,360


	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

As of March 31, 2024 and December 31, 2023, the Company had $3.6 million and $4.2 million, respectively, 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 condensed consolidated balance sheets.

No accrued interest receivable was written off during the three months ended March 31, 2024 and 2023. Realized gains or losses were immaterial for the three months ended March 31, 2024 and 2023.


	March 31, 2024
	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	$	100,615	$	(141	)	$	21,462	$	(98	)	$	122,077	$	(239	)
U.S. corporate bonds		115,218		(283	)		15,430		(57	)		130,648		(340	)
International corporate bonds		42,335		(114	)		5,718		(22	)		48,053		(136	)
U.S. commercial paper		4,914		(1	)		—		—			4,914		(1	)
International commercial paper		18,766		(7	)		—		—			18,766		(7	)
U.S. municipal securities		50,157		(104	)		14,948		(52	)		65,105		(156	)
	$	332,005	$	(650	)	$	57,558	$	(229	)	$	389,563	$	(879	)


	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	)

As of March 31, 2024 and December 31, 2023, the unrealized losses on the Company’s investments in U.S. government securities, U.S. corporate bonds, and international corporate bonds 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. As of March 31, 2024, the Company does not intend to sell those 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 March 31, 2024, 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 $46.3 million and maturities of one to two years.

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 and 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 three months ended March 31, 2024 and the year ended December 31, 2023.

Stock-Based Compensation - Summary of Activity Relating to Time Based and Performance Based Stock Options (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ending balance, Outstanding Shares	11,170,620
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, Outstanding Shares	8,118,041
Granted, Shares	2,030,551
Exercised, Shares	(7,142)
Forfeited, Shares	(3,165,816)
Ending balance, Outstanding Shares	6,975,634	8,118,041
Exercisable, Shares	3,931,681
Beginning balance, Outstanding Weighted Average Exercise Price	$ 76.02
Granted, Weighted Average Exercise Price	22.41
Exercised, Weighted Average Exercise Price	7.18
Forfeited, Weighted Average Exercise Price	86.34
Ending balance, Outstanding Weighted Average Exercise Price	55.81	$ 76.02
Exercisable, Weighted Average Exercise Price	$ 70
Outstanding, Weighted Average Remaining Life	5 years 11 months 4 days	5 years 7 months 28 days
Exercisable, Weighted Average Remaining Life	4 years 6 months 18 days
Outstanding, Aggregate Intrinsic Value	$ 231	$ 475
Exercisable, Aggregate Intrinsic Value	$ 231

Commitments and Contingencies - University of California License Agreements - Additional Information (Detail) - University of California License Agreements [Member] - USD ($)		1 Months Ended	3 Months Ended		12 Months Ended	106 Months Ended
	Dec. 31, 2015	Jun. 30, 2015	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2015	Mar. 31, 2024
Commitments And Contingencies [Line Items]
Upfront payment		$ 50,000
Annual license maintenance fee					$ 15,000
Milestone payments			$ 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

Stock-Based Compensation - Summary of Stock-Based Compensation Expense by Award Type (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	$ 13,698	$ 20,038
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	7,451	10,015
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	5,719	9,553
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	$ 528	$ 470

- 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
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 35
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480483/718-10-35-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)
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-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(ii)
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iii)
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-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(01)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(02)
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-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(03)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(04)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(ii)
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-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
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-Paragraph 2
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Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
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-Paragraph 2
-Subparagraph (c)(2)(iii)(01)
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Reference 18: http://www.xbrl.org/2003/role/disclosureRef
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Reference 19: http://www.xbrl.org/2003/role/disclosureRef
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Reference 20: http://www.xbrl.org/2003/role/disclosureRef
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Reference 21: http://www.xbrl.org/2003/role/disclosureRef
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Reference 22: http://www.xbrl.org/2003/role/disclosureRef
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Reference 23: http://www.xbrl.org/2003/role/disclosureRef
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Reference 24: http://www.xbrl.org/2003/role/disclosureRef
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Reference 25: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(ii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 26: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(iii)
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-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 27: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
-Section 50
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-Subparagraph (f)(2)(iv)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 28: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(v)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

+ Details

Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2024
Summary Of Significant Accounting Policies [Line Items]
Incremental costs incurred expected amortization period of asset	true

Collaboration Agreements (Tables)

3 Months Ended

Mar. 31, 2024

Collaboration Agreement [Abstract]

Summary of Activity and Reimbursement Amounts Related to Collaboration Agreement

the U.S., as well as ongoing costs related to the development of SAGE-217 products and SAGE-324 products, as reflected in our condensed consolidated statement of operations and comprehensive loss:


	Three Months Ended March 31,
	2024		2023
	(in thousands)
Collaboration revenue - related party	$	6,212	$	—
Cost of revenues		1,201		—
Research and development expenses		7,031		22,171
Selling, general and administrative expenses		12,983		18,963


	Three Months Ended March 31,
	2024			2023
	(in thousands)
Collaboration revenue - related party	$	(6,212	)	$	—
Cost of revenues		(562	)		—
Research and development expenses		(5,657	)		(17,282	)
Selling, general and administrative expenses		2,306			3,034

Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2024

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 March 31, 2024 and December 31, 2023:


	March 31, 2024
	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	$	159,464	$	159,464	$	—	$	—
U.S. government securities		4,983		—		4,983		—
U.S. corporate bonds		1,993		—		1,993		—
International corporate bonds		4,962		—		4,962		—
Total cash equivalents		171,402		159,464		11,938		—
Marketable securities:
U.S. government securities		136,725		—		136,725		—
U.S. corporate bonds		181,949		—		181,949		—
International corporate bonds		83,861		—		83,861		—
U.S. commercial paper		30,357		—		30,357		—
International commercial paper		45,059		—		45,059		—
U.S. certificates of deposit		1,303		—		1,303		—
U.S. municipal securities		65,106		—		65,106		—
Total marketable securities		544,360		—		544,360		—
	$	715,762	$	159,464	$	556,298	$	—


	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	$	—

Accrued Expenses

3 Months Ended

Mar. 31, 2024

Payables and Accruals [Abstract]

Accrued Expenses

5. Accrued Expenses

The following table summarizes accrued expenses as of March 31, 2024 and December 31, 2023:


	March 31,		December 31,
	2024		2023
	(in thousands)
Accrued research and development costs	$	30,627	$	26,040
Restructuring		2,568		10,589
Employee-related		7,092		21,339
Professional services		11,178		8,589
Other		549		707
	$	52,014	$	67,264

Stock-Based Compensation - Additional Information (Detail)				3 Months Ended		12 Months Ended
	Feb. 21, 2024 $ / shares shares	Jan. 01, 2024 shares	Jun. 15, 2023 shares	Mar. 31, 2024 USD ($) Milestone $ / shares shares	Mar. 31, 2023 USD ($) Milestone $ / shares shares	Dec. 31, 2023 $ / shares shares	Apr. 16, 2024 shares	Jan. 23, 2024 $ / shares	Jun. 16, 2022 shares	Sep. 20, 2018 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
Stock-based compensation expense tied to total stockholder return \| $				$ 13,698,000	$ 20,038,000
Total number of shares outstanding				11,170,620
Common stock available for issuance under stock option plan				6,627,028
Stock-based compensation expense \| $				$ 13,698,000	$ 20,038,000
Total unrecognized stock-based compensation expense \| $				$ 45,800,000
Weighted average grant date fair value per share \| $ / shares				$ 15.11	$ 29.65
Time Based Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units granted				857,084	330,617
Restricted stock units vested				69,943	14,494
Fair value of restricted stock units vested \| $				$ 1,600,000	$ 600,000
Outstanding and unvested restricted stock units				2,399,564
Total unrecognized stock-based compensation expense \| $				$ 33,800,000
Performance Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense tied to total stockholder return \| $				$ 300,000	$ 21,000
Restricted stock units granted				395,055	822,718
Fair value of restricted stock units vested \| $				$ 0
Outstanding and unvested restricted stock units				1,795,422
Total unrecognized stock-based compensation expense \| $				$ 70,700,000
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted				2,030,551
Stock options exercise price per share \| $ / shares				$ 55.81		$ 76.02
Total number of shares outstanding				6,975,634		8,118,041
Stock-based compensation expense \| $				$ 7,451,000	$ 10,015,000
Weighted average period of unrecognized compensation costs				2 years 7 months 28 days
Intrinsic value of options exercised \| $				$ 100,000	1,700,000
Exercise price per share of the replacement options \| $ / shares				$ 70
Options elected to be cancelled				3,165,816
Performance-Based Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense \| $				$ 0	$ 0
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted				0	0
Total unrecognized stock-based compensation expense \| $				$ 24,900,000
Number of shares outstanding and unvested stock options				455,000
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units granted				1,252,139
Stock-based compensation expense \| $				$ 5,719,000	$ 9,553,000
Outstanding and unvested restricted stock units				4,194,986		3,088,394
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				0
2014 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares annual increase added to plan		2,401,745
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 \| $					5,500,000
Stock-based compensation expense \| $					$ 8,500,000
Regulatory development Milestone achieved \| Milestone					1
2014 Plan [Member] \| Performance-Based Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Regulatory development Milestone achieved \| Milestone				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										1,200,000
2016 Plan [Member] \| Subsequent Event [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total number of shares reserved for issuance							428,074
2014 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional number of shares reserved for issuance			500,000
Total number of shares reserved for issuance			1,082,000						300,000
Option Exchange Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted	1,483,113
Share based compensation granted under plan vested period	18 months
Share based compensation, term of plan	7 years
Exercise price per share of the replacement options \| $ / shares	$ 22.2
Options to purchase	3,079,608
Additional stock-based compensation expense \| $				$ 1,700,000
Replacement options vesting period				18 months
Option Exchange Program [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options exercise price per share \| $ / shares								$ 35

Investments - Summary of Fair Value And Unrealized Losses of Marketable Securities In Loss Position (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	$ 332,005	$ 343,373
Less than 12 months, Unrealized Losses	(650)	(611)
Greater than 12 months, Fair Value	57,558	123,121
Greater than 12 months, Unrealized Losses	(229)	(640)
Fair Value	389,563	466,494
Unrealized Losses	(879)	(1,251)
U.S. Government Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	100,615	52,521
Less than 12 months, Unrealized Losses	(141)	(96)
Greater than 12 months, Fair Value	21,462	41,911
Greater than 12 months, Unrealized Losses	(98)	(251)
Fair Value	122,077	94,432
Unrealized Losses	(239)	(347)
U.S. Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	115,218	111,901
Less than 12 months, Unrealized Losses	(283)	(246)
Greater than 12 months, Fair Value	15,430	43,851
Greater than 12 months, Unrealized Losses	(57)	(238)
Fair Value	130,648	155,752
Unrealized Losses	(340)	(484)
International Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	42,335	43,708
Less than 12 months, Unrealized Losses	(114)	(87)
Greater than 12 months, Fair Value	5,718	6,014
Greater than 12 months, Unrealized Losses	(22)	(35)
Fair Value	48,053	49,722
Unrealized Losses	(136)	(122)
U.S. Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	4,914	7,848
Less than 12 months, Unrealized Losses	(1)	(1)
Fair Value	4,914	7,848
Unrealized Losses	(1)	(1)
International Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	18,766	37,300
Less than 12 months, Unrealized Losses	(7)	(38)
Fair Value	18,766	37,300
Unrealized Losses	(7)	(38)
U.S. Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	50,157	90,095
Less than 12 months, Unrealized Losses	(104)	(143)
Greater than 12 months, Fair Value	14,948	31,345
Greater than 12 months, Unrealized Losses	(52)	(116)
Fair Value	65,105	121,440
Unrealized Losses	$ (156)	$ (259)

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Mar. 31, 2024
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

Fair Value Measurements

3 Months Ended

Mar. 31, 2024

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 March 31, 2024 and December 31, 2023.

The following tables summarize the Company’s cash equivalents and marketable securities as of March 31, 2024 and December 31, 2023:


	March 31, 2024
	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	$	159,464	$	159,464	$	—	$	—
U.S. government securities		4,983		—		4,983		—
U.S. corporate bonds		1,993		—		1,993		—
International corporate bonds		4,962		—		4,962		—
Total cash equivalents		171,402		159,464		11,938		—
Marketable securities:
U.S. government securities		136,725		—		136,725		—
U.S. corporate bonds		181,949		—		181,949		—
International corporate bonds		83,861		—		83,861		—
U.S. commercial paper		30,357		—		30,357		—
International commercial paper		45,059		—		45,059		—
U.S. certificates of deposit		1,303		—		1,303		—
U.S. municipal securities		65,106		—		65,106		—
Total marketable securities		544,360		—		544,360		—
	$	715,762	$	159,464	$	556,298	$	—


	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	$	—

During the three months ended March 31, 2024 and 2023, there were no transfers among the Level 1, Level 2 and Level 3 categories.

Condensed Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Deficit [Member]
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 exercises of stock options, Amount	438			438
Issuance of common stock from exercises of stock options, Shares		52,058
Issuance of common stock under the employee stock purchase plan	2,863			2,863
Issuance of common stock under the employee stock purchase plan, Shares		76,105
Stock-based compensation expense	19,568			19,568
Change in unrealized loss on available-for-sale securities	5,118				5,118
Vesting of restricted stock units, net of employee tax obligations	(629)			(629)
Vesting of restricted stock units, net of employee tax obligations, Shares		124,713
Net loss	(146,828)					(146,828)
Balances at Mar. 31, 2023	1,133,129	$ 6	$ (400)	3,313,609	(5,088)	(2,174,998)
Balance, Shares at Mar. 31, 2023		59,762,001	3,033
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
Issuance of common stock from exercises of stock options, Amount	52			52
Issuance of common stock from exercises of stock options, Shares		7,142
Issuance of common stock under the employee stock purchase plan	1,507			1,507
Issuance of common stock under the employee stock purchase plan, Shares		61,402
Stock-based compensation expense	13,170			13,170
Change in unrealized loss on available-for-sale securities	27				27
Vesting of restricted stock units, net of employee tax obligations	(2)			(2)
Vesting of restricted stock units, net of employee tax obligations, Shares		69,844
Net loss	(108,483)					(108,483)
Balances at Mar. 31, 2024	$ 705,801	$ 6	$ (400)	$ 3,385,124	$ (787)	$ (2,678,142)
Balance, Shares at Mar. 31, 2024		60,182,031	3,033

Net Loss Per Share (Tables)

3 Months Ended

Mar. 31, 2024

Earnings Per Share [Abstract]

Summary of Basic and Diluted Net Loss Per Share

The following table shows the calculation of basic and diluted net loss per share for the three months ended March 31, 2024 and 2023:


	Three Months Ended March 31,
	2024			2023
Basic net loss per share:
Numerator:
Net loss (in thousands)	$	(108,483	)	$	(146,828	)
Denominator:
Weighted average common stock outstanding - basic and diluted		60,136,198			59,674,127
Net loss per share - basic and diluted	$	(1.80	)	$	(2.46	)

Summary of Potential Dilutive Securities Outstanding


	Three Months Ended March 31,
	2024		2023
Stock options		6,520,634		7,733,310
Restricted stock units		2,399,564		470,891
Employee stock purchase plan		52,975		46,846
		8,973,173		8,251,047

Restructuring (Tables)

3 Months Ended

Mar. 31, 2024

Restructuring and Related Activities [Abstract]

Schedule of Restructuring Accrual

The following table summarizes activity related to the restructuring accrual during the three months ended March 31, 2024:


	Restructuring Accrual
	(in thousands)
Balance as of December 31, 2023	$	10,589
Restructuring expenses incurred		(597	)
Cash paid		(7,424	)
Non-cash activity		—
Balance as of March 31, 2024	$	2,568

Commitments and Contingencies - Operating Leases - Additional Information (Detail)	1 Months Ended	3 Months Ended
	Jan. 31, 2024 USD ($) ft²	Mar. 31, 2024 USD ($) ft²	Dec. 31, 2023 USD ($)
Commitments And Contingencies [Line Items]
Operating lease option to extend		true
Operating lease renewal term		5 years
Operating lease, right-of-use asset		$ 2,857,000	$ 4,458,000
Lease Agreements [Member]
Commitments And Contingencies [Line Items]
Office space rent under operating lease \| ft²	30,567
Lease expire date	Aug. 31, 2024
Operating lease option to extend		The Company has the option to extend the New Lease one time for an additional five-year period
Expected commencement lease date	Sep. 01, 2024
Operating lease, right-of-use asset		$ 0
Operating lease, liability		$ 0
Initial term	66 months
Monthly base rent for first year	$ 224,158
Monthly base rent increase percentage	3.00%
Operating lease option to extend additional period	5 years
Letter of Credit [Member] \| Lease Agreements [Member]
Commitments And Contingencies [Line Items]
Security deposit	$ 1,400,000
Security deposit amount reduced for third anniversary	1,200,000
Operating Lease One [Member]
Commitments And Contingencies [Line Items]
Office space rent under operating lease \| ft²		63,017
Lease expire date		Aug. 31, 2024
Operating Lease Two [Member]
Commitments And Contingencies [Line Items]
Office space rent under operating lease \| ft²		40,419
Lease expire date		Aug. 31, 2024
Operating Lease Three [Member]
Commitments And Contingencies [Line Items]
Office space rent under operating lease \| ft²		15,525
Lease expire date		Nov. 30, 2024
Maximum [Member]
Commitments And Contingencies [Line Items]
Operating lease remaining lease terms		1 year
Maximum [Member] \| Lease Agreements [Member]
Commitments And Contingencies [Line Items]
Construction allowance.	$ 3,400,000

Collaboration Agreements - Additional Information (Detail) - USD ($)			1 Months Ended	3 Months Ended				12 Months Ended
	Nov. 30, 2020	Jun. 30, 2018	Jan. 31, 2024	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2022	Jun. 30, 2018	Dec. 31, 2023	Dec. 31, 2020	Jun. 12, 2018
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue				$ 7,902,000	$ 3,294,000
Collaboration receivable - related party				10,509,000				$ 83,009,000
Shionogi Collaboration Agreement [Member] \| Collaboration Revenue [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue				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				(6,212,000)				8,000,000
Milestone achieved								75,000,000
Payments to related parties				0	0
Proceeds from related parties				82,600,000		$ 12,900,000
Biogen Collaboration Agreement [Member] \| Related Party [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration receivable - related party				10,500,000				83,000,000
Biogen Collaboration Agreement [Member] \| License And Milestone Revenue - Related Party [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue				$ 0	$ 0			$ 75,000,000
Milestone payments			$ 75,000,000
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
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

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash flows from operating activities
Net loss	$ (108,483)	$ (146,828)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	13,698	20,038
Premium on marketable securities	(23)	(29)
Amortization of discount on marketable securities	(1,554)	(3,179)
Depreciation expense	336	323
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	5,237	(8,024)
Collaboration receivable - related party	72,500	(1,342)
Other long-term assets	332	515
Right-of-use operating asset	1,601	1,470
Operating lease liabilities, current	(1,859)	41
Operating lease liabilities, non-current	0	(1,728)
Accounts payable	(3,839)	(6,550)
Accrued expenses and other liabilities	(15,778)	(8,389)
Net cash used in operating activities	(37,832)	(153,682)
Cash flows from investing activities
Proceeds from sales and maturities of marketable securities	201,054	351,982
Purchases of marketable securities	(61,618)	(156,890)
Purchases of property and equipment	0	(225)
Net cash provided by investing activities	139,436	194,867
Cash flows from financing activities
Proceeds from stock option exercises and employee stock purchase plan issuances	1,559	3,301
Payment of employee tax obligations related to vesting of restricted stock units	(2)	(629)
Net cash provided by financing activities	1,557	2,672
Net increase in cash, cash equivalents and restricted cash	103,161	43,857
Cash, cash equivalents and restricted cash at beginning of period	72,324	163,969
Cash, cash equivalents and restricted cash at end of period	$ 175,485	$ 207,826

Fair Value Measurements - Additional Information (Detail) - USD ($)	Mar. 31, 2024	Mar. 31, 2023
Debt Instrument Fair Value Carrying Value [Line Items]
Transfers among the Level 1, Level 2 and Level 3 categories	$ 0	$ 0

Stock-Based Compensation

3 Months Ended

Mar. 31, 2024

Share-Based Payment Arrangement [Abstract]

Stock-Based Compensation

9. 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 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, 2024, 2,401,745 shares of common stock, representing 4% of the Company’s outstanding shares of common stock as of December 31, 2023, 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. On April 16, 2024, the Board amended the 2016 Plan to reduce the number of shares reserved for issuance thereunder to 428,074 shares and to provide that no further grants may be made under the 2016 Plan after April 16, 2024.

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 and generally expire 10 years after the date of grant.

As of March 31, 2024, the total number of shares underlying outstanding awards under all equity plans was 11,170,620 and the total number of shares available for future issuance under all equity plans was 6,627,028 shares.

On June 16, 2022, the Company’s stockholders approved an amendment to the amended 2014 Employee Stock Purchase Plan (the “ESPP”), which had been previously approved by the Board, to add 300,000 shares of common stock to the ESPP. On June 15, 2023, the Company’s stockholders approved another amendment to the ESPP, which had been previously approved by the Board, to add an additional 500,000 shares of common stock to the ESPP. As amended, a total of 1,082,000 shares of common stock have been authorized for issuance under the ESPP.

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 were given the opportunity to exchange certain outstanding stock options (the “Eligible 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”) upon the terms and subject to the conditions set forth in the Offer to Exchange Eligible Options for Replacement Options dated January 23, 2024 (the “Offer to Exchange”). Stock options eligible for exchange had an exercise price per share of $35.00 or greater, in addition to certain other requirements, and were 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 was February 21, 2024. 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. The Company accepted for exchange Eligible Options to purchase a total of 3,079,608 shares of the Company’s common stock. All tendered Eligible Options were cancelled effective as of February 21, 2024, and promptly thereafter, in exchange thereof, the Company granted replacement options for a total of 1,483,113 shares of the Company’s common stock, pursuant to the terms of the Offer to Exchange and the 2014 Plan. The exercise price per share of the replacement options was $22.20 per share, which was the closing price per share of the Company’s common stock on the Nasdaq Global Market on February 21, 2024. The replacement options vest over 18 months from the date of grant and have a term of seven years.

The Company expects to incur a total of $1.7 million of additional stock-based compensation expense as a result of the Option Exchange, to be recognized over the 18-month vesting period of the replacement options.

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, 2023		3,088,394		$	34.27
Granted		1,252,139		$	23.67
Vested		(69,943	)	$	44.66
Forfeited		(75,604	)	$	35.69
Outstanding as of March 31, 2024		4,194,986		$	30.91

Time-based restricted stock units

During the three months ended March 31, 2024 and 2023, the Company granted 857,084 and 330,617 time-based restricted stock units, respectively, to its employees and consultants.

During the three months ended March 31, 2024 and 2023 there were 69,943 and 14,494 time-based restricted stock units that vested, respectively. The fair value on the date of vesting for the three months ended March 31, 2024 and 2023 was $1.6 million and $0.6 million, respectively.

As of March 31, 2024, 2,399,564 time-based restricted stock units were both outstanding and unvested, and the total unrecognized stock-based compensation expense related to these awards was $33.8 million.

Performance restricted stock units

During the three months ended March 31, 2024 and 2023, the Company granted 395,055 and 822,718 performance restricted stock units, respectively, to its employees and consultants. The majority of the performance restricted stock units vest upon the achievement of certain clinical and regulatory development milestones related to product candidates and certain 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 expense 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 and for the three months ended March 31, 2024 and 2023, for performance restricted stock units that were outstanding, and other than performance restricted stock units for which the 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. During the three months ended March 31, 2024 and 2023, the Company recorded $0.3 million and $21,000 of stock-based compensation expense, respectively, related to performance restricted stock units for which vesting is tied to total stockholder return.

During the three months ended March 31, 2024, no outstanding performance restricted stock units vested.

During the three months ended March 31, 2023, one regulatory development milestone for outstanding performance restricted stock units was achieved. The fair value of the performance restricted stock units that vested upon achievement was $5.5 million and the Company recognized stock-based compensation expense related to this milestone of $8.5 million.

As of March 31, 2024, 1,795,422 performance restricted stock units were both outstanding and unvested, and the total unrecognized stock-based compensation expense related to these awards was $70.7 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, 2023		8,118,041		$	76.02		5.66	$	475
Granted		2,030,551		$	22.41
Exercised		(7,142	)	$	7.18
Forfeited		(3,165,816	)	$	86.34
Outstanding as of March 31, 2024		6,975,634		$	55.81		5.93	$	231
Exercisable as of March 31, 2024		3,931,681		$	70.00		4.55	$	231

As of March 31, 2024, the Company had unrecognized stock-based compensation expense related to its outstanding and unvested time-based stock option awards of $45.8 million, which is expected to be recognized over the remaining weighted average vesting period of 2.66 years.

The intrinsic value of stock options exercised during the three months ended March 31, 2024 and 2023 was $0.1 million and $1.7 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 March 31, 2024 and 2023, 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 during the three months ended March 31, 2024 and 2023, respectively.

During the three months ended March 31, 2024 and 2023, the Company granted no stock options to purchase shares of common stock that contain performance-based vesting criteria.

During the three months ended March 31, 2024 and 2023, no milestones were achieved under performance-based stock options.

As of March 31, 2024, 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 three months ended March 31, 2024 and 2023:


	Three Months Ended March 31,
	2024		2023
	(in thousands)
Research and development	$	4,965	$	8,773
Selling, general and administrative		8,733		11,265
	$	13,698	$	20,038

The following table summarizes stock-based compensation expense by award type recognized during the three months ended March 31, 2024 and 2023:


	Three Months Ended March 31,
	2024		2023
	(in thousands)
Stock options	$	7,451	$	10,015
Restricted stock units		5,719		9,553
Employee stock purchase plan		528		470
	$	13,698	$	20,038

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. 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 three months ended March 31, 2024 and 2023 was $15.11 and $29.65, respectively.

Stock-Based Compensation - Summary of Activity Relating to Restricted Stock Units (Detail) - Restricted Stock Units [Member]	3 Months Ended
	Mar. 31, 2024 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding, Shares at beginning balance \| shares	3,088,394
Granted, Shares \| shares	1,252,139
Vested, Shares \| shares	(69,943)
Forfeited, Shares \| shares	(75,604)
Outstanding, Shares at ending balance \| shares	4,194,986
Outstanding, Weighted Average Grant Date Fair Value at beginning balance \| $ / shares	$ 34.27
Granted, Weighted Average Grant Date Fair Value \| $ / shares	23.67
Vested, Weighted Average Grant Date Fair Value \| $ / shares	44.66
Forfeited, Weighted Average Grant Date Fair Value \| $ / shares	35.69
Outstanding, Weighted Average Grant Date Fair Value at ending balance \| $ / shares	$ 30.91

Summary of Significant Accounting Policies	3 Months Ended
Summary of Significant Accounting Policies	Mar. 31, 2024
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 condensed consolidated financial statements. Basis of Presentation The condensed consolidated financial statements of the Company included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission. Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) have been condensed or omitted from this report, as is permitted by such rules and regulations. Accordingly, these condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements as of and for the year ended December 31, 2023, included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023. The condensed consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements. In the opinion of the Company’s management, the accompanying condensed consolidated financial statements contain all adjustments, consisting of only normal recurring adjustments, necessary for a fair statement of its financial position as of March 31, 2024, its results of operations and comprehensive loss for the three months ended March 31, 2024 and 2023, its cash flows for the three months ended March 31, 2024 and 2023, and its statements of changes in stockholders’ equity for the three months ended March 31, 2024 and 2023. The consolidated balance sheet at December 31, 2023 was derived from audited financial statements, but does not include all disclosures required by GAAP. The results for the three months ended March 31, 2024 are not necessarily indicative of the results for the year ending December 31, 2024, or for any future period. Principles of Consolidation The condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries as disclosed in Note 2, Summary of Significant Accounting Policies, within the “Notes to Consolidated Financial Statements” accompanying its Annual Report on Form 10-K for the year ended December 31, 2023. Intercompany accounts and transactions have been eliminated. Use of Estimates The preparation of condensed 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 condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. 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. Revenue Recognition Under Accounting Standards Codification (“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 condensed 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 condensed 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 March 31, 2024, as customer invoicing generally occurs before or at the time of revenue recognition. The Company did not have any contract liabilities at March 31, 2024, 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 condensed consolidated balance sheets. As of March 31, 2024 and December 31, 2023, 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 condensed 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 condensed 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 condensed 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 condensed consolidated balance sheets. Product returns have not been 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 SSP 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 7, 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 condensed 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 7, Collaboration Agreements. 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 March 31, 2024 and December 31, 2023 were carried at fair value, determined according to the fair value hierarchy; see Note 3, Fair Value Measurements. The carrying amounts reflected in the condensed 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 March 31, 2024 and December 31, 2023, respectively. Recently Issued Accounting Pronouncements Accounting standards that have been issued or proposed by the Financial Accounting Standards Board 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 condensed consolidated financial statements upon adoption.

Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2024

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, 2023		3,088,394		$	34.27
Granted		1,252,139		$	23.67
Vested		(69,943	)	$	44.66
Forfeited		(75,604	)	$	35.69
Outstanding as of March 31, 2024		4,194,986		$	30.91

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, 2023		8,118,041		$	76.02		5.66	$	475
Granted		2,030,551		$	22.41
Exercised		(7,142	)	$	7.18
Forfeited		(3,165,816	)	$	86.34
Outstanding as of March 31, 2024		6,975,634		$	55.81		5.93	$	231
Exercisable as of March 31, 2024		3,931,681		$	70.00		4.55	$	231

Summary of Stock-Based Compensation Expense Recognized

The following table summarizes stock-based compensation expense recognized during the three months ended March 31, 2024 and 2023:


	Three Months Ended March 31,
	2024		2023
	(in thousands)
Research and development	$	4,965	$	8,773
Selling, general and administrative		8,733		11,265
	$	13,698	$	20,038

Summary of Stock-Based Compensation Expense by Award Type

The following table summarizes stock-based compensation expense by award type recognized during the three months ended March 31, 2024 and 2023:


	Three Months Ended March 31,
	2024		2023
	(in thousands)
Stock options	$	7,451	$	10,015
Restricted stock units		5,719		9,553
Employee stock purchase plan		528		470
	$	13,698	$	20,038

Document and Entity Information - shares	3 Months Ended
Document and Entity Information - shares	Mar. 31, 2024	Apr. 18, 2024
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Trading Symbol	SAGE
Entity Registrant Name	Sage Therapeutics, Inc.
Entity Central Index Key	0001597553
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Common Stock, Shares Outstanding		60,182,031
Entity Shell Company	false
Entity File Number	001-36544
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
Entity Interactive Data Current	Yes
Entity Incorporation, State or Country Code	DE
Document Quarterly Report	true
Document Transition Report	false

Restructuring - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Aug. 31, 2023	Mar. 31, 2024
Restructuring Cost and Reserve [Line Items]
Percentage of workforce eliminated	40.00%
Restructuring charges expected to be incurred		$ 32.8

- 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

Restructuring - Schedule of Restructuring Accrual (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)
Restructuring Reserve [Roll Forward]
Restructuring accrual, Balance as of July 1, 2023	$ 10,589
Restructuring expenses incurred	(597)
Cash paid	(7,424)
Non-cash activity	0
Restructuring accrual, Balance as of September 30, 2023	$ 2,568

Net Loss Per Share - Summary of Potential Dilutive Securities Outstanding (Detail) - shares	3 Months Ended
	Mar. 31, 2024	Sep. 30, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents	8,973,173	8,251,047
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents	6,520,634	7,733,310
Restricted Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents	2,399,564	470,891
Employee Stock Purchase Plan [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents	52,975	46,846

Stock-Based Compensation - Summary of Stock-Based Compensation Expense Recognized (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	$ 13,698	$ 20,038
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	4,965	8,773
Selling, General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	$ 8,733	$ 11,265

- 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

Accrued Expenses - Summary of Accrued Expenses (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Payables and Accruals [Abstract]
Accrued research and development costs	$ 30,627	$ 26,040
Restructuring	2,568	10,589
Employee-related	7,092	21,339
Professional services	11,178	8,589
Other	549	707
Total accrued expenses	$ 52,014	$ 67,264

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 172,653	$ 70,992
Marketable securities	544,360	682,192
Prepaid expenses and other current assets	26,588	31,825
Collaboration receivable - related party	10,509	83,009
Restricted cash	$ 1,332	$ 1,332
Accounts Receivable, after Allowance for Credit Loss, Current, Related Party, Type [Extensible Enumeration]	Related Party [Member]	Related Party [Member]
Total current assets	$ 755,442	$ 869,350
Property and equipment, net	1,585	1,921
Restricted cash	1,500	0
Right-of-use operating asset	2,857	4,458
Other long-term assets	6,216	6,548
Total assets	767,600	882,277
Current liabilities:
Accounts payable	6,479	10,318
Accrued expenses	52,014	67,264
Operating lease liability, current portion	3,306	5,165
Total current liabilities	61,799	82,747
Total liabilities	61,799	82,747
Commitments and contingencies (Note 6)
Stockholders’ equity:
Preferred stock, $0.0001 par value per share; 5,000,000 shares authorized at March 31, 2024 and December 31, 2023; no shares issued or outstanding at March 31, 2024 and December 31, 2023
Common stock, $0.0001 par value per share; 120,000,000 shares authorized at March 31, 2014 and December 31, 2023; 60,185,064 and 60,046,676 shares issued at March 31, 2024 and December 31, 2023; 60,182,031 and 60,043,643 shares outstanding at March 31,2024 and December 31, 2023	6	6
Treasury stock, at cost, 3,033 shares at March 31, 2024 and December 31, 2023	(400)	(400)
Additional paid-in capital	3,385,124	3,370,397
Accumulated deficit	(2,678,142)	(2,569,659)
Accumulated other comprehensive loss	(787)	(814)
Total stockholders’ equity	705,801	799,530
Total liabilities and stockholders’ equity	$ 767,600	$ 882,277