Sage Therapeutics (SAGE) 10-K 11 Feb 25 2024 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2024	Feb. 04, 2025	Jun. 28, 2024
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	FY
Trading Symbol	SAGE
Entity Registrant Name	Sage Therapeutics, Inc.
Entity Central Index Key	0001597553
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction	false
Entity Common Stock, Shares Outstanding		61,480,947
Entity Public Float			$ 590,463,402
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Security Exchange Name	NASDAQ
Entity File Number	001-36544
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	27-4486580
Entity Address, Address Line One	55 Cambridge Parkway
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02142
City Area Code	617
Local Phone Number	299-8380
Document Annual Report	true
Document Transition Report	false
Auditor Name	PricewaterhouseCoopers LLP
Auditor Firm ID	238
Auditor Location	Boston, Massachusetts
Documents Incorporated by Reference	Part III of this Annual Report on Form 10-K incorporates by reference certain information from the registrant’s definitive Proxy Statement for its 2025 annual meeting of shareholders, which the registrant intends to file pursuant to Regulation 14A with the Securities and Exchange Commission not later than 120 days after the registrant’s fiscal year end of December 31, 2024 . Except with respect to information specifically incorporated by reference in this Form 10-K, the Proxy Statement is not deemed to be filed as part of this Form 10-K.
Auditor Opinion [Text Block]	We have audited the accompanying consolidated balance sheets of Sage Therapeutics, Inc. and its subsidiaries (the “Company”) as of December 31, 2024 and 2023, and the related consolidated statements of operations and comprehensive loss, of changes in stockholders’ equity and of cash flows for each of the three years in the period ended December 31, 2024, including the related notes (collectively referred to as the “consolidated financial statements”). We also have audited the Company’s internal control over financial reporting as of December 31, 2024, based on criteria established in Internal Control - Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission (COSO). In our opinion, the consolidated financial statements referred to above present fairly, in all material respects, the financial position of the Company as of December 31, 2024 and 2023, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2024 in conformity with accounting principles generally accepted in the United States of America. Also in our opinion, the Company maintained, in all material respects, effective internal control over financial reporting as of December 31, 2024, based on criteria established in Internal Control - Integrated Framework (2013) issued by the COSO.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 81,021	$ 70,992
Marketable securities	423,397	682,192
Prepaid expenses and other current assets	17,749	31,825
Collaboration receivable - related party	$ 9,134	$ 83,009
Accounts Receivable, after Allowance for Credit Loss, Current, Related Party [Extensible Enumeration]	Related Party [Member]	Related Party [Member]
Restricted cash	$ 0	$ 1,332
Total current assets	531,301	869,350
Property and equipment, net	890	1,921
Restricted cash	1,450	0
Right-of-use operating asset	10,753	4,458
Other long-term assets	2,828	6,548
Total assets	547,222	882,277
Current liabilities:
Accounts payable	12,699	10,318
Accrued expenses	57,598	67,264
Operating lease liability, current portion	1,318	5,165
Total current liabilities	71,615	82,747
Operating lease liability, net of current portion	10,518	0
Total liabilities	82,133	82,747
Commitments and contingencies (Note 6)
Stockholders’ equity:
Preferred stock, $0.0001 par value per share; 5,000,000 shares authorized at December 31, 2024 and 2023; no shares issued or outstanding at December 31, 2024 and 2023
Common stock, $0.0001 par value per share; 120,000,000 shares authorized at December 31, 2024 and 2023; 61,359,242 and 60,046,676 shares issued at December 31, 2024 and 2023, respectively; 61,356,209 and 60,043,643 shares outstanding at December 31, 2024 and 2023, respectively	6	6
Treasury stock, at cost, 3,033 shares at December 31, 2024 and 2023	(400)	(400)
Additional paid-in capital	3,435,564	3,370,397
Accumulated deficit	(2,970,325)	(2,569,659)
Accumulated other comprehensive income (loss)	244	(814)
Total stockholders’ equity	465,089	799,530
Total liabilities and stockholders’ equity	$ 547,222	$ 882,277

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 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	61,359,242	60,046,676
Common stock, shares outstanding	61,356,209	60,043,643
Treasury stock, shares	3,033	3,033

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Total revenues	$ 41,243	$ 86,455	$ 7,686
Operating costs and expenses:
Cost of revenues	9,444	2,159	813
Research and development	225,895	356,235	326,163
Selling, general and administrative	216,420	274,524	227,699
Restructuring	21,854	33,386
Total operating costs and expenses	473,613	666,304	554,675
Loss from operations	(432,370)	(579,849)	(546,989)
Interest income, net	31,675	38,743	14,190
Other income (expense), net	29	(383)	15
Net loss	$ (400,666)	$ (541,489)	$ (532,784)
Net loss per share - basic	$ (6.59)	$ (9.05)	$ (8.98)
Net loss per share - diluted	$ (6.59)	$ (9.05)	$ (8.98)
Weighted average number of common shares outstanding—basic	60,765,913	59,836,441	59,306,094
Weighted average number of common shares outstanding—diluted	60,765,913	59,836,441	59,306,094
Comprehensive loss:
Net Income (Loss)	$ (400,666)	$ (541,489)	$ (532,784)
Other comprehensive items:
Unrealized gain (loss) on marketable securities	1,058	9,392	(7,546)
Total comprehensive loss	(399,608)	(532,097)	(540,330)
Product Revenue [Member]
Total revenues	3,574	10,454	$ 7,686
License And Milestone Revenue - Related Party [Member]
Total revenues		75,000
Collaboration Revenue - Related Party [Member]
Total revenues	36,087	824
Other Collaboration Revenue [Member]
Total revenues	$ 1,582	$ 177

Consolidated Statements of Op_2

Consolidated Statements of Operations and Comprehensive Loss (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Revenues	$ 41,243	$ 86,455	$ 7,686
Other Collaboration Revenue Related Party [Member]
Revenues	$ 947	$ 0	$ 0

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]
Balances at Dec. 31, 2021	$ 1,729,031	$ 6	$ (400)	$ 3,227,471	$ (2,660)	$ (1,495,386)
Balances, Shares at Dec. 31, 2021		58,937,050	3,033
Issuance of common stock from exercises of stock options, Amount	1,037			1,037
Issuance of common stock from exercises of stock options, Shares		150,045
Issuance of common stock under the employee stock purchase plan	2,346			2,346
Issuance of common stock under the employee stock purchase plan, Shares		57,239
Vesting of restricted stock units, net of employee tax obligations	(43)			(43)
Vesting of restricted stock units, net of employee tax obligations, Shares		364,791
Stock-based compensation expense	60,558			60,558
Change in unrealized gain (loss) on available-for-sale securities	(7,546)				(7,546)
Net Income (Loss)	(532,784)					(532,784)
Balances at Dec. 31, 2022	1,252,599	$ 6	$ (400)	3,291,369	(10,206)	(2,028,170)
Balances, Shares at Dec. 31, 2022		59,509,125	3,033
Issuance of common stock from exercises of stock options, Amount	1,293			1,293
Issuance of common stock from exercises of stock options, Shares		72,090
Issuance of common stock under the employee stock purchase plan	6,519			6,519
Issuance of common stock under the employee stock purchase plan, Shares		164,043
Vesting of restricted stock units, net of employee tax obligations	(903)			(903)
Vesting of restricted stock units, net of employee tax obligations, Shares		298,385
Stock-based compensation expense	72,119			72,119
Change in unrealized gain (loss) on available-for-sale securities	9,392				9,392
Net Income (Loss)	(541,489)					(541,489)
Balances at Dec. 31, 2023	799,530	$ 6	$ (400)	3,370,397	(814)	(2,569,659)
Balances, Shares at Dec. 31, 2023		60,043,643	3,033
Issuance of common stock from exercises of stock options, Amount	78			78
Issuance of common stock from exercises of stock options, Shares		10,062
Issuance of common stock under the employee stock purchase plan	2,941			2,941
Issuance of common stock under the employee stock purchase plan, Shares		216,886
Vesting of restricted stock units, net of employee tax obligations	(403)			(403)
Vesting of restricted stock units, net of employee tax obligations, Shares		385,618
Stock-based compensation expense	54,504			54,504
Issuance of common stock upon public offering, net of issuance costs	8,047			8,047
Issuance of common stock upon public offering, net of issuance costs, Shares		700,000
Change in unrealized gain (loss) on available-for-sale securities	1,058				1,058
Net Income (Loss)	(400,666)					(400,666)
Balances at Dec. 31, 2024	$ 465,089	$ 6	$ (400)	$ 3,435,564	$ 244	$ (2,970,325)
Balances, Shares at Dec. 31, 2024		61,356,209	3,033

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Cash flows from operating activities
Net loss	$ (400,666)	$ (541,489)	$ (532,784)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	54,504	73,367	61,602
Premium on marketable securities	(344)	(132)	(1,500)
Amortization of (discount) premium on marketable securities	(6,481)	(6,340)	5,853
Depreciation expense	1,031	1,393	1,122
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	14,076	19,001	(10,985)
Collaboration receivable - related party	73,875	(69,349)	4,846
Other long-term assets	3,720	(1,778)	(519)
Right-of-use operating asset	5,302	6,074	5,577
Operating lease liabilities, current	(3,847)	(2,478)	175
Operating lease liabilities, non-current	(1,079)	(4,491)	(6,473)
Accounts payable	2,381	(8,495)	8,433
Accrued expenses and other liabilities	(9,666)	(5,868)	4,617
Net cash used in operating activities	(267,194)	(540,585)	(460,036)
Cash flows from investing activities
Proceeds from sales and maturities of marketable securities	717,635	1,038,136	1,207,407
Purchases of marketable securities	(450,957)	(594,670)	(881,037)
Purchases of property and equipment	0	(553)	(937)
Net cash provided by investing activities	266,678	442,913	325,433
Cash flows from financing activities
Proceeds from stock option exercises and employee stock purchase plan issuances	3,019	6,930	3,113
Payments of offering costs	(117)	0	0
Proceeds from public offerings of common stock, net of commissions and underwriting discounts	8,164	0	0
Payment of employee tax obligations related to vesting of restricted stock units	(403)	(903)	(43)
Net cash provided by financing activities	10,663	6,027	3,070
Net increase (decrease) in cash, cash equivalents and restricted cash	10,147	(91,645)	(131,533)
Cash, cash equivalents and restricted cash at beginning of period	72,324	163,969	295,502
Cash, cash equivalents and restricted cash at end of period	82,471	72,324	163,969
Supplemental disclosure of non-cash operating activities
Right-of-use assets obtained in exchange for new operating lease liabilities	11,597	0	0
Purchases of property and equipment included in accounts payable	0	0	137
Reconciliation of cash, cash equivalents, and restricted cash reported in the consolidated balance sheets
Cash and cash equivalents	81,021	70,992	162,700
Restricted cash	1,450	1,332	1,269
Total cash, cash equivalents, and restricted cash shown in the statement of cash flows	$ 82,471	$ 72,324	$ 163,969

Cybersecurity Risk Management,

Cybersecurity Risk Management, Strategy, and Governance	12 Months Ended
	Dec. 31, 2024
Cybersecurity Risk Management, Strategy, and Governance [Line Items]
Cybersecurity Risk Management Processes for Assessing, Identifying, and Managing Threats [Text Block]	Item 1C. Cybersecurity Risk Management and Strategy As is the case for similar companies of our size and industry, we may be the target of cyber attacks and other cyber incidents and, therefore, cybersecurity is an important element of our overall enterprise risk management program. We have certain processes to systematically evaluate, identify, address, and manage cybersecurity risks, which are built into our overall risk management program and are designed to help safeguard our information assets and operational integrity from internal and external cyber threats, protect employee information from unauthorized access or attack, as well as secure our networks and systems. Such processes include physical, procedural, and technical safeguards, response plans, and continuity exercises on our systems. We also routinely review our policies and procedures to identify risks and refine our practices. By prioritizing cyber risk comprehension and management, we aim to enhance business resiliency, protect information from unauthorized access or attacks, and secure our digital footprint. We engage certain external parties, including cybersecurity and privacy firms, to enhance our cybersecurity oversight and risk reduction abilities. We also perform an annual cybersecurity assessment designed to help align our cybersecurity program with industry best practices. In addition, we regularly consult with industry groups, peer organizations, and external executives to assess the cybersecurity threat landscape throughout the year. Our cybersecurity policies, standards, and procedures include cyber and data breach response plans benchmarked against multiple cybersecurity risk frameworks. Our incident response plan is designed to help coordinate the response to and recovery from cybersecurity incidents and includes processes to identify, investigate, triage, assess the severity of, escalate, contain, and remediate incidents and comply with applicable legal or regulatory obligations. We also regularly perform technical reviews of our systems to help secure our digital environment and confirm software patches are appropriately up-to-date. To oversee and identify risks from cybersecurity threats associated with our use of third-party service providers , we have implemented a third-party risk management program designed to help protect against information misuse and assess the information technology security measures of potential third parties and business partners. We perform a third-party risk assessment before starting a relationship with certain service providers and utilize a third-party risk intelligence program to monitor the activity of critical vendors following engagement. In addition, we maintain cyber insurance coverage as part of our overall risk mitigation strategy. This cyber insurance coverage may not be sufficient to cover against all claims. We do not believe that there are currently any risks from cybersecurity threats that are reasonably likely to materially affect us or our business strategy, results of operations or financial condition. Governance Our Audit Committee of the Board of Directors provides direct oversight over cybersecurity risk. The Audit Committee receives annual updates from management regarding cybersecurity matters and is notified between such updates regarding significant new cybersecurity threats or incidents, if applicable. We also have a cybersecurity steering committee responsible for assisting with our overall day-to-day cybersecurity responsibilities and implementing our cybersecurity programs. The cybersecurity steering committee is currently comprised of members of our digital and enterprise capabilities team and is chaired by our executive director of cybersecurity . Among other things, the cybersecurity steering committee: • reviews our internal controls to help protect our information assets; • assists with developing practices, procedures, and controls designed to identify, assess, and manage critical cybersecurity programs and risks; and • works to align our risk governance structure, including policies and procedures, with our business objectives. The chair of the cybersecurity steering committee, our executive director of cybersecurity, has over 25 years of information technology industry experience, including 20 years focused on cybersecurity, and master’s degrees in a cybersecurity discipline and in business administration, in addition to multiple certifications related to information technology and cybersecurity. In addition, to help prevent and detect cybersecurity threats, we provide all employees, including part-time and temporary employees, with monthly cybersecurity and privacy training, which covers timely and relevant cybersecurity topics, including social engineering, phishing, password protection, confidential data protection, asset use, and mobile security .
Cybersecurity Risk Management Processes Integrated [Flag]	true
Cybersecurity Risk Management Processes Integrated [Text Block]	As is the case for similar companies of our size and industry, we may be the target of cyber attacks and other cyber incidents and, therefore, cybersecurity is an important element of our overall enterprise risk management program. We have certain processes to systematically evaluate, identify, address, and manage cybersecurity risks, which are built into our overall risk management program and are designed to help safeguard our information assets and operational integrity from internal and external cyber threats, protect employee information from unauthorized access or attack, as well as secure our networks and systems. Such processes include physical, procedural, and technical safeguards, response plans, and continuity exercises on our systems. We also routinely review our policies and procedures to identify risks and refine our practices. By prioritizing cyber risk comprehension and management, we aim to enhance business resiliency, protect information from unauthorized access or attacks, and secure our digital footprint.
Cybersecurity Risk Management Third Party Engaged [Flag]	true
Cybersecurity Risk Third Party Oversight and Identification Processes [Flag]	true
Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Flag]	false
Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Text Block]	We do not believe that there are currently any risks from cybersecurity threats that are reasonably likely to materially affect us or our business strategy, results of operations or financial condition.
Cybersecurity Risk Board of Directors Oversight [Text Block]	Our Audit Committee of the Board of Directors provides direct oversight over cybersecurity risk. The Audit Committee receives annual updates from management regarding cybersecurity matters and is notified between such updates regarding significant new cybersecurity threats or incidents, if applicable.
Cybersecurity Risk Board Committee or Subcommittee Responsible for Oversight [Text Block]	Our Audit Committee of the Board of Directors provides direct oversight over cybersecurity risk.
Cybersecurity Risk Process for Informing Board Committee or Subcommittee Responsible for Oversight [Text Block]	The Audit Committee receives annual updates from management regarding cybersecurity matters and is notified between such updates regarding significant new cybersecurity threats or incidents, if applicable.
Cybersecurity Risk Role of Management [Text Block]	We also have a cybersecurity steering committee responsible for assisting with our overall day-to-day cybersecurity responsibilities and implementing our cybersecurity programs. The cybersecurity steering committee is currently comprised of members of our digital and enterprise capabilities team and is chaired by our executive director of cybersecurity . Among other things, the cybersecurity steering committee: • reviews our internal controls to help protect our information assets; • assists with developing practices, procedures, and controls designed to identify, assess, and manage critical cybersecurity programs and risks; and • works to align our risk governance structure, including policies and procedures, with our business objectives. The chair of the cybersecurity steering committee, our executive director of cybersecurity, has over 25 years of information technology industry experience, including 20 years focused on cybersecurity, and master’s degrees in a cybersecurity discipline and in business administration, in addition to multiple certifications related to information technology and cybersecurity. In addition, to help prevent and detect cybersecurity threats, we provide all employees, including part-time and temporary employees, with monthly cybersecurity and privacy training, which covers timely and relevant cybersecurity topics, including social engineering, phishing, password protection, confidential data protection, asset use, and mobile security .
Cybersecurity Risk Management Positions or Committees Responsible [Flag]	true
Cybersecurity Risk Management Positions or Committees Responsible [Text Block]	We also have a cybersecurity steering committee responsible for assisting with our overall day-to-day cybersecurity responsibilities and implementing our cybersecurity programs. The cybersecurity steering committee is currently comprised of members of our digital and enterprise capabilities team and is chaired by our executive director of cybersecurity .
Cybersecurity Risk Management Expertise of Management Responsible [Text Block]	The chair of the cybersecurity steering committee, our executive director of cybersecurity, has over 25 years of information technology industry experience, including 20 years focused on cybersecurity, and master’s degrees in a cybersecurity discipline and in business administration, in addition to multiple certifications related to information technology and cybersecurity.
Cybersecurity Risk Process for Informing Management or Committees Responsible [Text Block]	In addition, to help prevent and detect cybersecurity threats, we provide all employees, including part-time and temporary employees, with monthly cybersecurity and privacy training, which covers timely and relevant cybersecurity topics, including social engineering, phishing, password protection, confidential data protection, asset use, and mobile security
Cybersecurity Risk Management Positions or Committees Responsible Report to Board [Flag]	true

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Pay vs Performance Disclosure
Net Income (Loss)	$ (400,666)	$ (541,489)	$ (532,784)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Dec. 31, 2024
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	Director and Officer Trading Arrangements In connection with Gregory Shiferman ’s appointment as an executive officer on November 1, 2024 , Mr. Shiferman’s durable sale instruction pertaining to eligible sell-to-cover transactions (as described in Rule 10b5-1(c)(1)(ii)(D)(3) under the Exchange Act) in connection with his restricted stock unit (“RSU”) and performance restricted stock unit (“PSU”) awards terminated automatically in accordance with its terms, and his RSU and PSU award agreements were amended to replace their sell-to-cover provisions with share-withholding provisions in accordance with our standard practice to require share withholding for all RSUs and PSUs held by our executive officers. Other than as set forth above, no ne of our directors or officers adopted or terminated a Rule 10b5-1 trading arrangement or a non-Rule 10b5-1 trading arrangement (as defined in Item 408(c) of Regulation S-K) during the fourth quarter of 2024.
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
Gregory Shiferman [Member]
Trading Arrangements, by Individual
Name	Gregory Shiferman
Title	executive officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	November 1, 2024

Insider Trading Policies and Pr

Insider Trading Policies and Procedures	3 Months Ended
	Dec. 31, 2024
Insider Trading Policies and Procedures [Line Items]
Insider Trading Policies and Procedures Adopted	true

Nature of the Business

Nature of the Business	12 Months Ended
	Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of the Business	1. 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 GABA A receptors, targeting both synaptic and extrasynaptic GABA A 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 currently approved in the U.S. for the treatment of PPD in individuals 15 years old and older and was launched commercially in the U.S. in June 2019. ZULRESSO may only be administered in qualified, medically-supervised healthcare settings. The Company discontinued commercial availability of ZULRESSO in the U.S. as of December 31, 2024. The Company supported scheduled ZULRESSO infusions through the end of 2024. As a result of the decision to discontinue ZULRESSO commercial availability, during the year ended December 31, 2024, the Company incurred $ 5.4 million of incremental cost related to impairment of intangible assets, excess inventory write-off, prepaid and other current assets accelerated amortization, and accrued termination costs. 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 GABA A 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. The Company is targeting diseases and disorders of the brain across its pipeline. In October 2024, the Company executed a plan to reorganize its business operations, including a reduction of approximately 33 % of the Company’s total workforce and approximately 55 % of the Company’s research and development workforce. See Note 14, Restructuring , for further details. 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 authorities prior to commercial sales. There can be no assurance that the current and future product candidates of the Company will receive, or that 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, 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 Inc. (“Biogen”) (the “Biogen Collaboration Agreement”). As of December 31, 2024, the Company had an accumulated deficit of $ 3.0 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 consolidated financial statements. At some point after that time, the Company anticipates it will require additional financing to fund its future operations. Even if the Company believes it has sufficient funds for its current or future operating plans, the Company may seek to raise additional capital if market conditions are favorable or in light of other strategic considerations.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 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 consolidated financial statements. Basis of Presentation The accompanying consolidated financial statements include those of the Company and its subsidiaries after elimination of all intercompany accounts and transactions. The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the U.S. (“GAAP”). Principles of Consolidation The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. Intercompany accounts and transactions have been eliminated. Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Cash Equivalents The Company considers all highly liquid investments with an original maturity of 90 days or less to be cash equivalents. As of December 31, 2024, cash equivalents were comprised of money market funds, U.S. government securities, and U.S. commercial paper. As of December 31, 2023 , cash equivalents were comprised of money market funds and U.S. government securities. Marketable Securities Marketable securities consist of investments with original maturities greater than 90 days. The Company has classified its investments with maturities beyond one year as short-term, based on their highly liquid nature and because such marketable securities represent the investment of cash that is available for current operations. The Company considers its investment portfolio of marketable securities to be available-for-sale. Accordingly, these investments are recorded at fair value, which is based on quoted market prices. Unrealized gains and losses are reported as the accumulated other comprehensive items in stockholders’ equity. When the fair value is below the amortized cost of the asset, an estimate of expected credit losses is made. The credit-related impairment amount is recognized in net income (loss); the remaining impairment amount and unrealized gains are reported as a component of accumulated other comprehensive items in stockholders’ equity. Credit losses are recognized through the use of an allowance for credit losses account and subsequent improvements in expected credit losses are recognized as a reversal of an amount in the allowance for credit losses account. If the Company has the intent to sell the security or it is more likely than not that the Company will be required to sell the security prior to recovery of its amortized cost basis, then the allowance for the credit loss is written-off and the excess of the amortized cost basis of the asset over its fair value is recorded in the consolidated statements of operations and comprehensive loss. Regardless of the Company’s intent to sell a security, it performs additional analysis on all securities with unrealized losses to evaluate losses associated with the creditworthiness of the security. Credit losses are identified where the Company does not expect to receive cash flows sufficient to recover the amortized cost basis of a security. The Company adjusts the cost of available-for-sale debt securities for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion are included in interest income. The cost of securities sold is based on the specific identification method. The Company includes interest and dividends on securities classified as available-for-sale in interest income. Accounts Receivable The Company’s trade accounts receivable consist of amounts due from specialty distributors and specialty pharmacies that have been certified under a Risk Evaluation and Mitigation Strategy program in the U.S. related to sales of ZULRESSO and have standard payment terms that generally require payment within 30 to 90 days from the invoice date. The Company monitors the financial performance and creditworthiness of customers so that it can properly assess and respond to changes in their credit profiles. The Company makes judgments as to its ability to collect outstanding receivables and provides an allowance for bad debts against the trade account receivables, when appropriate. As of December 31, 2024 and 2023, trade accounts receivable were $ 0.4 million and $ 1.4 million, respectively, and are included in prepaid expenses and other current assets on the consolidated balance sheets. As of December 31, 2024 , the Company has not provided any allowance for bad debts against the trade accounts receivable. Inventory Prior to the initial date that regulatory approval is received for a product candidate of the Company, costs related to the production of inventory are recorded as research and development expense on the Company’s consolidated statements of operations and comprehensive loss in the period incurred. Inventory is stated at the lower of cost or estimated net realizable value with cost determined on a first-in, first-out basis. Inventory costs may include purchases of raw materials, third-party contract manufacturing services, third-party packaging services, salary related expenses, overhead costs, and freight. Raw and intermediate materials that may be utilized for either research and development or commercial purposes, after approval of the product by the FDA, are classified as inventory. Amounts in inventory that are used for research and development purposes are charged to research and development expense when the product enters the research and development process and can no longer be used for commercial purposes and, therefore, does not have an “alternative future use” as defined in authoritative guidance. The Company performs an assessment of the recoverability of capitalized inventory during each reporting period and, if needed, writes down any excess and obsolete inventory to its estimated net realizable value in the period it is identified. If they occur, such impairment charges are recorded as a component of cost of revenues in the consolidated statements of operations and comprehensive loss. As of December 31, 2024 , the Company did no t have any capitalized inventory on hand. As of December 31, 2023, inventory was $ 1.5 million, and is included in prepaid expenses and other current assets on the consolidated balance sheets. Property and Equipment Property and equipment are recorded at cost and depreciated over their estimated useful lives using the straight-line method. Upon retirement or sale, the cost of assets disposed of and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is credited or charged to the Company’s consolidated statements of operations and comprehensive loss. Repairs and maintenance costs are expensed as incurred. Leases The Company determines if an arrangement is a lease at contract inception. Operating lease assets represent the Company’s right to use an underlying asset for the lease term and operating lease liabilities represent the Company’s obligation to make payments arising from the lease. Operating lease assets and liabilities are recognized at the commencement date of the lease based upon the present value of lease payments over the lease term. When determining the lease term, the Company includes options to extend or terminate the lease when it is reasonably certain that the Company will exercise those options. The Company uses the Company’s incremental borrowing rate when the implicit interest rate is not readily determinable based upon the information available at the commencement date of the lease in determining the present value of the lease payments and the implicit interest rate when readily determinable. The lease payments used to determine the Company’s operating lease assets may include lease incentives, stated rent increases and escalation clauses linked to rates of inflation, when determinable, and are recognized in the Company’s operating lease assets in the Company’s consolidated balance sheets. In addition, the Company’s contracts may contain lease and non-lease components. The Company combines lease and non-lease components, which are accounted for together as lease components. The Company’s operating leases are reflected in the right-of-use operating asset; operating lease liability, current portion; and operating lease liability, net of current portion in the Company’s consolidated balance sheets. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. Short-term leases, defined as leases that have a lease term of 12 months or less at the commencement date, are not recorded on the Company’s consolidated balance sheets and are recognized in the consolidated statements of operations and comprehensive loss on a straight-line basis over the term of the lease. Variable lease payments are the amounts owed by the Company to a lessor that are not fixed, such as reimbursement for common area maintenance and utilities costs for facility leases. Variable lease payments are expensed when incurred. Impairment of Long-Lived Assets Long-lived assets consist of property and equipment and lease right-of-use assets. Long-lived assets to be held and used are tested for recoverability whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends, and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long-lived asset group for recoverability, the Company compares forecasts of undiscounted cash flows expected to result from the use and eventual disposition of the long-lived asset group to its carrying value. The impairment loss would be based on the excess of the carrying value of the impaired asset over its fair value, determined based on discounted cash flows. During the year ended December 31, 2024 , the Company recorded $ 2.2 million of impairment losses on long-lived assets as a result of discontinuing the commercial availability of ZULRESSO. During the year ended December 31, 2023 , the Company did not record any impairment losses on long-lived assets. Cost of Revenues Cost of revenues includes direct and indirect costs related to the manufacturing and distribution of ZULRESSO, including third-party contract manufacturing costs, packaging services, freight, third-party royalties payable on the Company’s net product revenue of ZULRESSO and amortization of intangible assets associated with ZULRESSO. Cost of revenues also includes our proportionate share of ZURZUVAE manufacturing costs under the Biogen Collaboration Agreement, (for additional information, refer to Note 7, Collaboration Agreements ). Cost of revenues may also include period costs related to certain inventory manufacturing services and inventory adjustment charges. Prior to receiving FDA approval of ZULRESSO in March 2019 and ZURZUVAE in August 2023, the Company manufactured inventory in preparation for launch. As a result, certain manufacturing costs associated with revenues were expensed prior to FDA approval and, therefore, a portion of such costs are not included in cost of revenues during the years ended December 31, 2024, 2023, and 2022 . Research and Development Costs and Accruals Research and development expenses are comprised of costs incurred in performing research and development activities, including salaries and benefits, overhead costs, depreciation, contract services and other related costs. Research and development costs are expensed to operations as the related obligation is incurred. The Company has entered into various research and development contracts with research institutions and other companies both inside and outside of the U.S. These agreements are generally cancelable, and related costs are recorded as research and development expenses as incurred. The Company records accruals for estimated ongoing research and development costs. When billing terms under these contracts do not coincide with the timing of when the work is performed, the Company is required to make estimates of outstanding obligations to those third parties as of the end of the reporting period. Any accrual estimates are based on a number of factors, including the Company’s knowledge of the progress towards completion of the research and development activities, invoicing to date under the contracts, communication from the research institution or other companies of any actual costs incurred during the period that have not yet been invoiced, and the costs included in the contracts. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from the estimates made by the Company. The historical accrual estimates made by the Company have not been materially different from the actual costs. Stock-Based Compensation The Company recognizes stock-based compensation expense for grants under our equity incentive plans and employee stock purchase plan. The Company accounts for all stock-based awards granted to employees at their fair value and recognize compensation expense over the vesting period of the award. Determining the amount of stock-based compensation to be recorded requires the Company to develop estimates of fair values of stock options as of the grant date. The Company calculates the grant date fair values of stock options using the Black-Scholes valuation model, which requires the input of subjective assumptions, including but not limited to expected stock price volatility over the term of the awards, the expected term of stock options and the expected forfeiture rate. The fair value of restricted stock awards granted to employees is based upon the quoted closing market price per share on the date of grant. The Company has performance conditions included in certain of its performance restricted stock units that are based upon the achievement of pre-specified clinical development, regulatory, commercial and/or financial performance events. As the outcome of each event has inherent risk and uncertainties, and a positive outcome may not be known until the event is achieved, the Company begins to recognize the value of the performance-based restricted stock awards when the Company determines the achievement of each performance condition is deemed probable, a determination which requires significant judgment by management. At the probable date, the Company records estimated cumulative expense to date, with remaining expense amortized over the remaining service period until achievement has occurred. Treasury Stock The Company records treasury stock at cost. Treasury stock consists of shares of the Company’s common stock received from a then-employee as consideration for exercises of stock options. Basic and Diluted Net Loss Per Share Basic net loss per share is computed by dividing the net loss by the weighted average number of common shares outstanding for the period. For periods in which the Company has reported net losses, diluted net loss per share is the same as basic net loss per share, because dilutive common shares are not assumed to have been issued if their effect is antidilutive. The Company reported a net loss for the years ended December 31, 2024, 2023 and 2022. Concentration of Credit Risk and of Significant Suppliers Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash, cash equivalents and marketable securities. The Company maintains accounts for all cash and cash equivalents at accredited financial institutions, and consequently, the Company believes that such funds are subject to minimal credit risk. The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. The Company’s marketable securities, which primarily consist of U.S. government agency securities and treasuries, corporate bonds and commercial paper, potentially subject the Company to concentrations of credit risk. The Company has adopted an investment policy that limits the amounts the Company may invest in any one type of investment, defines allowable investments, and requires all investments held by the Company to minimum credit rating standards, thereby reducing credit risk exposure. The Company has no significant off-balance sheet concentrations of credit risk, such as foreign currency exchange contracts, option contracts, or other hedging arrangements . The Company is dependent on third-party manufacturers to supply products for research and development activities for its programs. The Company also relies on and expects to continue to rely on third-party manufacturers to supply it with active pharmaceutical ingredients (“API”) and formulated drugs; and to provide other services related to manufacturing activities for these programs. These programs could be adversely affected by a significant interruption in the supply of API and formulated drugs, or the interruption of manufacturing related services. Income Taxes The Company accounts for income taxes under the asset and liability method. Under this method, deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted rates in effect for the year in which these temporary differences are expected to be recovered or settled. Valuation allowances are provided if, based on the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company accounts for uncertain tax positions in accordance with the provisions of Accounting Standards Codification (“ASC”) Topic 740, “ Income Taxes ”. When uncertain tax positions exist, the Company recognizes the tax benefit of tax positions to the extent that the benefit will more likely than not be realized. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. The Company accrues for potential interest and penalties related to unrecognized tax benefits in income tax expense. Fair Value Measurements Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Financial assets and liabilities carried at fair value are classified and disclosed in one of the following three categories: Level 1 — Quoted market prices in active markets for identical assets or liabilities. Level 2 — Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The Company’s cash equivalents and marketable securities at December 31, 2024 and 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 consolidated balance sheets for the collaboration receivable – related party, accounts payable, and accrued expenses approximate their fair values due to their short-term maturities at December 31, 2024 and 2023 , respectively. Comprehensive Income (Loss) Comprehensive loss includes net loss and other changes in stockholders’ equity that result from transactions and economic events other than those with stockholders. The Company’s only element of other comprehensive income (loss) is unrealized gains and losses on marketable securities that are considered to be available-for-sale. Revenue Recognition Under ASC Topic 606, Revenue from Contracts with Customers (“Topic 606”), an entity recognizes revenue when or as performance obligations are satisfied by transferring control of promised goods or services to a customer, in an amount that reflects the consideration that the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of Topic 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price, including variable consideration, if any; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. Arrangements that include rights to additional goods or services that are exercisable at a customer’s discretion are generally considered options. The Company assesses if these options provide a material right to the customer and if so, they are considered performance obligations. The exercise of a material right may be accounted for as a contract modification or as a continuation of the contract for accounting purposes. Topic 606 applies to all contracts with customers, except for contracts that are within the scope of other standards, such as collaboration arrangements. For contracts determined to be within the scope of Topic 606, the Company assesses whether the goods or services promised within each contract are distinct to identify those that are performance obligations. This assessment involves subjective determinations and requires management to make judgments about the individual promised goods or services and whether such are separable from the other aspects of the contractual relationship. Promised goods and services are considered distinct provided that: (i) the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer and (ii) the entity’s promise to transfer the good or service to the customer is separately identifiable from other promises in the contract. The Company allocates the transaction price (the amount of consideration it expects to be entitled to from a customer in exchange for the promised goods or services) to each performance obligation and recognizes the associated revenue when (or as) each performance obligation is satisfied. The Company’s estimate of the transaction price for each contract includes all variable consideration to which the Company expects to be entitled. Product Revenue, Net Until the discontinuation of commercial availability of ZULRESSO as of December 31, 2024, the Company generated product revenue from the sale of ZULRESSO to a limited number of specialty distributors and specialty pharmacy providers in the U.S. The Company recognized product revenue, net of variable consideration related to certain allowances and accruals that are determined using the expected value method, in its consolidated financial statements at the point in time when control transfers to the customer, which was 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 was to deliver the product to the location specified by the customer’s order. The Company records shipping and handling costs associated with delivery of product to its customers within selling, general and administrative expenses on its consolidated statements of operations and comprehensive loss. The Company expenses incremental costs of obtaining a contract as incurred if the expected amortization period of the asset would be less than one year. If the Company were to incur incremental costs with an amortization period greater than a year, such costs would be capitalized as contract assets, as they are expected to be recovered, and would be expensed by amortizing on a systematic basis that is consistent with the transfer to the customer of the goods or services to which the asset relates. The Company did not have any contract assets (unbilled receivables) at December 31, 2024, as customer invoicing generally occurs before or at the time of revenue recognition. The Company did not have any contract liabilities at December 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 consolidated balance sheets. As of December 31, 2024 and 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 ZULRESSO sold by the Company during the reporting period, as well as its estimate of product that remains in the distribution channel inventory of its customers at the end of the reporting period. On a quarterly basis, the Company updates its estimates, if necessary, and records any material adjustments in the period they are identified. Chargebacks : The Company estimates chargebacks from its customers who directly purchase the product from the Company for discounts resulting from contractual commitments to sell products to eligible healthcare settings at prices lower than the list prices charged to its customers. Customers charge the Company for the difference between what they pay to the Company for the product and the selling price to the eligible healthcare settings. Reserves for chargebacks consist of credits that the Company expects to issue for units that remain in the distribution channel inventories at the end of each reporting period that the Company expects will be sold to eligible healthcare settings, and chargebacks that customers have claimed, but for which the Company has not yet issued a credit. Government Rebates : The Company is subject to discount obligations under government programs, including Medicaid. The Company records reserves for rebates in the same period the related product revenue is recognized, resulting in a reduction of ZULRESSO product revenue and a current liability that is included in accrued expenses on its consolidated balance sheets. The Company’s liability for these rebates consists of invoices received for claims from prior quarters that have not been paid or for which an invoice has not yet been received, estimates of claims for the current quarter, and estimates of future claims that will be made for product that has been recognized as revenue, but which remains in the distribution channel at the end of each reporting period. Trade Discounts and Allowances : The Company generally provides customary invoice discounts on ZULRESSO sales to its customers for prompt payment and the Company pays fees for sales order management, data, and distribution services. The Company estimates its customers will earn these discounts and fees and deducts these discounts and fees in full from gross ZULRESSO revenue and accounts receivable at the time the Company recognizes the related revenue. Financial Assistance : The Company provides voluntary financial assistance programs for ZULRESSO to patients with commercial insurance that have coverage and reside in states that allow financial assistance. The Company estimates the financial assistance amounts for ZULRESSO and records any such amounts within accrued expenses on its consolidated balance sheets. The calculation of the accrual for financial assistance is based on an estimate of claims and the cost per claim that the Company expects to receive using demographics for patients who have registered and been approved for assistance. Any adjustments are recorded in the same period the related revenue is recognized, resulting in a reduction of product revenue and the establishment of a current liability, which is included as a component of accrued expenses on the consolidated balance sheets. Product Returns : Consistent with industry practice, the Company offers product return rights with respect to ZULRESSO to customers for damaged, defective or expiring product, provided it is within a specified period around the product expiration date as set forth in the Company’s return goods policy. The Company estimates the amount of its product sales that may be returned by its customers and records this estimate as a reduction of revenue in the period the related product revenue is recognized, as well as a reserve within accrued expenses on the consolidated balance sheets. Product returns have 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 mil

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2024
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. Fair Value Measurements The Company’s cash equivalents are classified within Level 1 and Level 2 of the fair value hierarchy. The Company’s investments in marketable securities are classified within Level 2 of the fair value hierarchy. The fair values of the Company’s marketable securities are based on prices obtained from independent pricing sources. Consistent with the fair value hierarchy described in Note 2, Summary of Significant Accounting Policies , marketable securities with validated quotes from pricing services are reflected within Level 2, as they are primarily based on observable pricing for similar assets or other market observable inputs. Typical inputs used by these pricing services include, but are not limited to, reported trades, benchmark yields, issuer spreads, bids, offers or estimates of cash flow, prepayment spreads and default rates. The Company performs validation procedures to ensure the reasonableness of this data. The Company performs its own review of prices received from the independent pricing services by comparing these prices to other sources. After completing the validation procedures, the Company did not adjust or override any fair value measurements provided by the pricing services as of December 31, 2024 and 2023. The following tables summarize the Company’s cash equivalents and marketable securities as of December 31, 2024 and 2023: December 31, 2024 Total Quoted Significant Significant (in thousands) Cash equivalents: Money market funds $ 73,845 $ 73,845 $ — $ — U.S. government securities 5,397 — 5,397 — U.S. commercial paper 997 — 997 — Total cash equivalents 80,239 73,845 6,394 — Marketable securities: U.S. government securities 36,457 — 36,457 — U.S. corporate bonds 269,013 — 269,013 — International corporate bonds 52,461 — 52,461 — U.S. commercial paper 30,373 — 30,373 — International commercial paper 24,144 — 24,144 — U.S. certificates of deposit 900 — 900 — U.S. municipal securities 10,049 — 10,049 — Total marketable securities 423,397 — 423,397 — $ 503,636 $ 73,845 $ 429,791 $ — December 31, 2023 Total Quoted Significant Significant (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 years ended December 31, 2024 and 2023 , there were no transfers among the Level 1, Level 2 and Level 3 categories.

Investments

Investments	12 Months Ended
	Dec. 31, 2024
Investments, Debt and Equity Securities [Abstract]
Investments	4. Investments 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 December 31, 2024 and 2023: December 31, 2024 Amortized Gross Unrealized Gross Unrealized Credit Losses Fair Value (in thousands) Assets: U.S. government securities $ 36,444 $ 18 $ ( 5 ) $ — $ 36,457 U.S. corporate bonds 268,841 305 ( 133 ) — 269,013 International corporate bonds 52,411 65 ( 15 ) — 52,461 U.S. commercial paper 30,373 — — — 30,373 International commercial paper 24,144 — — — 24,144 U.S. certificates of deposit 900 — — — 900 U.S. municipal securities 10,040 9 — — 10,049 $ 423,153 $ 397 $ ( 153 ) $ — $ 423,397 December 31, 2023 Amortized Gross Unrealized Gross Unrealized 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 December 31, 2024 and 2023 , the Company had $ 3.4 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 consolidated balance sheets . No accrued interest receivable was written off during years ended December 31, 2024, 2023, and 2022. Realized gains or losses were immaterial for the years ended December 31, 2024, 2023, and 2022. The following tables summarize the fair value and the unrealized losses of the Company’s marketable securities that have been in a loss position for either less than twelve months or greater than twelve months as of December 31, 2024 and 2023: December 31, 2024 Less than 12 months Greater than 12 months Total Fair Unrealized Fair Unrealized Fair Unrealized (in thousands) U.S. government securities $ 11,032 $ ( 5 ) $ — $ — $ 11,032 $ ( 5 ) U.S. corporate bonds 83,946 ( 129 ) 10,197 ( 4 ) 94,143 ( 133 ) International corporate bonds 7,312 ( 15 ) — — 7,312 ( 15 ) $ 102,290 $ ( 149 ) $ 10,197 $ ( 4 ) $ 112,487 $ ( 153 ) December 31, 2023 Less than 12 months Greater than 12 months Total Fair Unrealized Fair Unrealized Fair Unrealized (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 December 31, 2024 and 2023, the unrealized losses on the Company’s investments in U.S. government securities, U.S. corporate bonds, international corporate bonds, and U.S. municipal securities were caused by interest rate increases. The Company purchased those investments at a premium relative to their face amount. The current credit ratings are all within the guidelines of the investment policy of the Company and the Company does not expect the issuers to settle any security at a price less than the amortized cost basis of the investment. The Company does not intend to sell the investments and it is not probable that the Company will be required to sell the investments before recovery of their amortized cost basis. As of December 31, 2024 , all marketable securities held by the Company had remaining contractual maturities of one year or less, except for U.S. corporate bonds and international corporate bonds with a fair value of $ 30.7 million that had 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 that had maturities of one to two years . All marketable securities, including those with remaining contractual maturities of more than one year, are classified as current assets on the balance sheet because they are considered to be “available-for-sale” and the Company can convert them into cash to fund current operations. There have been no impairments of the Company’s assets measured and carried at fair value during the years ended December 31, 2024 and 2023 .

Balance Sheet Components

Balance Sheet Components	12 Months Ended
	Dec. 31, 2024
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Components	5. Balance Sheet Components Property and Equipment, net The following table summarizes property and equipment, net, as of December 31, 2024 and 2023: December 31, 2024 2023 (in thousands) Computer hardware and software $ 852 $ 2,114 Furniture and equipment 822 1,786 Leasehold improvements — 5,509 1,674 9,409 Less: Accumulated depreciation ( 784 ) ( 7,488 ) $ 890 $ 1,921 Depreciation expense for the years ended December 31, 2024, 2023, and 2022 was $ 1.0 million, $ 1.4 million, and $ 1.1 million, respectively. The useful life for computer hardware and software is three years , furniture and equipment is five years , and leasehold improvements is the lesser of the useful life or the term of the respective lease. Accrued Expenses The following table summarizes accrued expenses as of December 31, 2024 and 2023: December 31, December 31, 2024 2023 (in thousands) Accrued research and development costs $ 19,758 $ 26,040 Restructuring 15,307 10,589 Employee-related 14,840 21,339 Professional services 7,114 8,589 Other 579 707 $ 57,598 $ 67,264 As of December 31, 2024 and 2023 , accrued research and development costs includes $ 0.4 and $ 4.3 million, respectively, of accrued expenses related to canceling excess purchase commitments for manufacturing as a result of the complete response letter (“CRL”) received in August 2023 from the FDA related to the New Drug Application (“NDA”) for zuranolone for the treatment of major depressive disorder (“MDD”). During the year ended December 31, 2023 , $ 28.9 million of expenses related to the cancelation of excess purchase commitments were recorded as research and development expense in the consolidated statements of operations and comprehensive loss, net of amounts subject to reimbursement under the Biogen Collaboration Agreement of $ 14.5 million.

Leases, Commitments and Conting

Leases, Commitments and Contingencies	12 Months Ended
	Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Leases, Commitments and Contingencies	6. Leases, Commitments and Contingencies Operating Leases The Company leases office space and certain equipment. All of the leases recorded on the consolidated balance sheets are operating leases. The Company’s leases have remaining lease terms ranging from less than one year to approximately five years . Some of the leases include options to extend the leases for up to five years . These options were not included for the purpose of determining the right-of-use assets and associated lease liabilities as the Company determined that the renewal of these leases is not reasonably certain so only the original lease term was taken into consideration. The leases do not include any restrictions or covenants that had to be accounted for under the lease guidance. During the fiscal years ended December 31, 2024, 2023, and 2022, the Company leased office space in three multi-tenant buildings in Cambridge, Massachusetts, consisting of 63,017 square feet in the first building, under an operating lease that expired on August 31, 2024 ; 40,419 square feet in the second building, under an operating lease that expired on August 31, 2024 ; and 30,567 square feet in the third building, under an operating lease that commenced in August 2024 that will expire on February 28, 2030 ; and in a multi-tenant building in Raleigh, North Carolina, consisting of 15,525 square feet under an operating lease that expired on November 30, 2024 . In January 2024, the Company entered into the lease agreement (the “New Lease”) for office space in a multi-tenant building in Cambridge, Massachusetts (the “New Premises”). The accounting lease commencement in accordance with ASC 842, Leases , occurred on August 2, 2024, and the Company recorded a total associated right-of-use asset of $ 11.6 million and the corresponding lease liability of $ 10.0 million. This includes a reclassification of $ 1.5 million from prepaid expenses and other current assets to right-of-use asset related to build out costs which were determined to be owned by the lessor. The contractual term of the New Lease commenced on September 1, 2024 (the “Term Commencement Date”), which is the date the Company relocated its headquarters to the New Premises. The Company’s obligation for the payment of rent for the New Premises begins six months after the Term Commencement Date (the “Rent Commencement Date”). The New Lease has an initial term of approximately sixty-six month s, measured from the Term Commencement Date (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; however, the exercise of the option to extend the lease term was not determined to be reasonably certain, and the Company will therefore recognize lease expense through the expiration of the New Lease Term in February 2030 . 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, classified within long-term restricted cash on the consolidated balance sheets, 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. During the year ended December 31, 2021, the Company entered into a sublease for a portion of the leased office space in the second multi-tenant building in Cambridge, Massachusetts, which was terminated effective April 5, 2024. The following table shows the amounts of operating leases in the balance sheets as of December 31, 2024 and 2023: December 31, Balance sheet location Balance sheet caption 2024 2023 (in thousands) Assets Right-of-use operating asset Right-of-use operating asset $ 10,753 $ 4,458 Liabilities Current operating lease Operating lease liability, current portion 1,318 5,165 Long-term operating lease Operating lease liability, net of current portion 10,518 — $ 11,836 $ 5,165 The following table shows the amounts of lease expense by lease type that was recognized during the years ended December 31, 2024, 2023, and 2022: Year Ended December 31, 2024 2023 2022 (in thousands) Operating lease cost $ 5,972 $ 6,748 $ 6,748 Variable lease cost 1,454 1,957 1,846 Short-term lease cost 20 20 206 Sublease income — ( 434 ) ( 421 ) $ 7,446 $ 8,291 $ 8,379 The Company made an accounting policy election not to apply the recognition requirements to short-term leases. The Company recognizes the lease payments for short-term leases as expense on a straight-line basis over the lease term, and variable lease payments in the period in which the obligation for those payments is incurred. The minimum lease payments are expected to be as follows: Years Ending December 31, (In thousands) 2025 $ 2,461 2026 2,976 2027 3,059 2028 3,144 2029 3,232 Thereafter 542 Total lease payments 15,414 Less imputed interest ( 3,578 ) Present value of operating lease liabilities $ 11,836 The following table shows the weighted average remaining lease term and weighted average discount rate of the operating leases: Year ended December 31, 2024 2023 Weighted average remaining lease term in years 5.17 0.69 Weighted average discount rate 10.0 % 7.5 % The interest rate implicit in lease contracts is typically not readily determinable and as such, the Company uses its incremental borrowing rate based on the information available at the lease commencement date, which represents an internally developed rate that would be incurred to borrow, on a collateralized basis, over a similar term, an amount equal to the lease payments in a similar economic environment. The following table shows the supplemental disclosure of cash flow information related to the operating leases included in cash flows used by operating activities in the consolidated statements of cash flows: Year Ended December 31, 2024 2023 2022 (in thousands) Cash paid for amounts included in the $ 3,958 $ 7,643 $ 7,468 Right-of-use assets obtained in exchange $ 11,597 $ — $ — Legal Proceedings On August 28, 2024, named plaintiff Darren Korver filed a purported federal securities class action lawsuit in the Southern District of New York against the Company and individuals, Barry E. Greene and Kimi Iguchi (the “Securities Class Action”). The complaint in the Securities Class Action alleges violations of U.S. securities laws under Sections 10(b) and 20(a) of the Securities Exchange Act of 1934 and Rule 10b-5 promulgated thereunder and seeks an as-yet unspecified amount of damages allegedly sustained by parties who purchased Sage stock between April 12, 2021 and July 23, 2024, as well as applicable attorneys’ fees and costs. The Company denies any allegations of wrongdoing and intends to vigorously defend against the Securities Class Action. On October 16, 2024, the Company received a subpoena from the Enforcement Division of the SEC requesting documents and information related to the Company’s NDA for zuranolone for the treatment of MDD, including communications with the FDA and any communications containing material nonpublic information. The Company is cooperating with the SEC and intends to continue to provide information responsive to the SEC’s requests. At this time, the Company is unable to predict the outcome of the Securities Class Action or the SEC investigation or reasonably estimate a range of possible losses. On January 16, 2025, the Company commenced litigation against Biogen in the Delaware Court of Chancery seeking declaratory, injunctive and other relief. In its complaint, the Company alleges that Biogen breached the standstill provision in the stock purchase agreement it entered into with Biogen on November 27, 2020 (the “Biogen Stock Purchase Agreement”), by making an unsolicited acquisition proposal and related public disclosures. On this basis, the Company also sought a temporary restraining order enjoining Biogen from future breaches of the standstill provision. At a hearing held on January 28, 2025, the Court granted the Company’s motion for a temporary restraining order against Biogen MA Inc., and entered an implementing order on January 30, 2025 (the “TRO Order”). Pursuant to the TRO Order, unless consented to by the Company in writing or otherwise ordered by the court, Biogen MA Inc. and its directors, officers, agents, employees, attorneys, representatives, persons in active concert or participation with it, and anyone acting under its direction or control are enjoined from taking any action inconsistent with the Biogen Stock Purchase Agreement’s contractual prohibitions against (i) making a public acquisition proposal, (ii) making a private acquisition proposal that is reasonably expected to require public disclosure, or (iii) publicly encouraging any acquisition proposal. Various motions and related items (whether procedural, discovery-related and/or substantive in nature) occur from time to time with respect to this matter. The Company intends to continue to vigorously pursue its claims against Biogen, but the Company is unable to predict the outcome of the litigation at this time.

Collaboration Agreements

Collaboration Agreements	12 Months Ended
	Dec. 31, 2024
Shionogi Collaboration Agreement [Member]
Collaboration Agreement	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 and license 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 was originally 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 originally included 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 potential future milestone payments for achievement of specified regulatory milestones was reduced to $ 55.0 million upon failure to received FDA approval of zuranolone for the treatment of MDD in the U.S. prior to December 31, 2023. 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. As between the Company and Shionogi, the Company maintains exclusive rights to develop and commercialize zuranolone outside of the Shionogi Territory. The upfront cash payment and any payments for milestones and royalties are non-refundable and non-creditable. Due to the uncertainty of pharmaceutical development and the high historical failure rates generally associated with drug development, the Company may not receive any milestone payments or any royalty payments from Shionogi. The Company concluded that Shionogi meets the definition of a customer because the Company is delivering intellectual property and know-how rights for the zuranolone program in support of territories in which the parties are not jointly sharing the risks and rewards. In addition, the Company determined that the Shionogi collaboration met the requirements to be accounted for as a contract, including that it is probable that the Company will collect the consideration to which the Company is entitled in exchange for the goods or services that will be delivered to Shionogi. The Company determined that the performance obligations in the Shionogi collaboration agreement included the license to zuranolone and the supply of certain materials during the clinical development phase, which includes the supply of API. The performance obligation related to the license to zuranolone was determined to be distinct from other performance obligations and therefore was a separate performance obligation for which control was transferred upon signing. The obligation to provide certain clinical materials, including API for use during the development period, was determined to be a separate performance obligation. Given that Shionogi is not obligated to purchase any minimum amount or quantities of commercial API, the supply of API to Shionogi for commercial use was determined to be an option for Shionogi, rather than a performance obligation of the Company at contract inception and will be accounted for if and when exercised. The Company also determined that there was no separate material right in connection with the supply of API for commercial use as the expected pricing was not at a discount. Given this fact pattern, the Company has concluded the agreement has two performance obligations. Under the clinical supply agreement, the Company is obligated to manufacture and supply to Shionogi (i) clinical quantities of API reasonably required by Shionogi for the development of licensed products in the Shionogi Territory under the collaboration and license agreement and (ii) quantities of drug product reasonably required for use by Shionogi in Phase 1 clinical trials of zuranolone in the Shionogi Territory under the collaboration and license agreement, in the quantities agreed to by the parties. Collaboration revenue from the clinical supply agreement, which 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 consolidated statements of operations and comprehensive loss. During the years ended December 31, 2024 and 2023, $ 0.6 million and $ 0.2 million, respectively, of collaboration revenue was recognized from the Company’s agreement with Shionogi. During the year ended December 31, 2022, no collaboration revenue was recognized from the Company’s agreement with Shionogi. The Company completed the evaluation of the SSP of each of the performance obligations and determined that the SSP 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 and SAGE-324 products. Concurrently, the Company also entered into 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 September 2024, Biogen notified the Company of its termination of the Biogen Collaboration Agreement solely with respect to products containing the Company’s SAGE-324 products on a worldwide basis, effective February 17, 2025 (the “SAGE-324 Termination”), in accordance with the required notice period. As a result of the SAGE-324 Termination, as of February 17, 2025 (the “SAGE-324 Termination effective date”), all licenses granted by the Company to Biogen or by Biogen to the Company regarding the SAGE-324 products shall expire with respect to the SAGE-324 products on a worldwide basis. Biogen shall grant to the Company an irrevocable, perpetual license for any Biogen background technology, Biogen collaboration technology or joint collaboration technology that exists as of February 17, 2025 with respect to the SAGE-324 products, in each case in accordance with the terms of the Biogen Collaboration Agreement. 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 was initially eligible to receive additional payments of up to $ 1.6 billion from Biogen if certain regulatory and commercial milestones were achieved. The potential future milestone payments for SAGE-217 products included 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. 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. In the fourth quarter of 2023, the Company achieved the $ 75.0 million milestone for the first commercial sale of ZURZUVAE for the treatment of women with PPD in the U.S. Because the Company and Biogen have agreed not to pursue further development of zuranolone for the treatment of MDD in the U.S., the Company will not receive the $ 150.0 million milestone payment for the first commercial sale of ZURZUVAE for the treatment of MDD in the U.S. The potential future milestone payments for SAGE-324 products initially included 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. As a result of the SAGE-324 Termination, the Company will not receive any milestone payments for SAGE-324 products under the Biogen Collaboration Agreement. The Company is also eligible to receive tiered royalties on net sales of SAGE-217 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. under the Biogen Collaboration Agreement are conducted pursuant to plans agreed to by the Company and Biogen and overseen by a joint steering committee that consists 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, prior to the SAGE-324 Termination, 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. 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 the agreement further provides that Biogen 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 (such as the SAGE-324 Termination) 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 at contract inception 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 fourth quarter of the year ended December 31, 2023. Payment of the $ 75.0 million milestone was received in January 2024. During the years ended December 31, 2024 and 2022, 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, through the SAGE-324 Termination effective date, SAGE-324 products in the U.S. to be separate units of account within the scope of Topic 808 as the Company and Biogen are both active participants in the development and commercialization activities and are exposed to significant risks and rewards that are dependent on the development and commercial success of the activities in the arrangement. While Biogen is considered the principal in transactions with customers for the sale of ZURZUVAE globally, the Company is also engaged in significant commercialization activities, including maintaining its own U.S. direct sales force. The Company presents its proportionate share of Biogen’s ZURZUVAE sales to customers in the U.S. as collaboration revenue - related party. Payments to or reimbursements from Biogen related to the agreement of the parties to share equally in all revenue and costs are accounted for as an increase to collaboration revenue, an increase to or reduction of cost of revenues, research and development expenses, or selling, general and administrative expenses, in the consolidated statements 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 costs during the periods related to the development of SAGE-217 products and SAGE-324 products, as reflected in our consolidated statements of operations and comprehensive loss: Year Ended December 31, 2024 2023 2022 (in thousands) Collaboration revenue - related party $ 36,087 $ 824 $ — Cost of revenues 5,428 504 — Research and development expenses 20,617 94,325 86,028 Selling, general and administrative expenses 58,950 89,599 51,870 The revenue, cost and expense categories in the table above reflects the following reimbursement amounts to (from) Biogen to account for the sharing of economics under the Biogen Collaboration Agreement: Year Ended December 31, 2024 2023 2022 (in thousands) Collaboration revenue - related party $ ( 36,087 ) $ ( 824 ) $ — Cost of revenues ( 2,723 ) 504 — Research and development expenses ( 15,680 ) ( 76,208 ) ( 73,227 ) Selling, general and administrative expenses 10,881 16,496 ( 2,230 ) As of December 31, 2024, the Company recorded a collaboration receivable – related party of $ 9.1 million, representing net reimbursement for amounts due for the three months ended December 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 year ended December 31, 2024 , no payments were made to Biogen and the Company received $ 118.1 million from Biogen for the amounts due for the three months ended December 31, 2023 and the nine months ended September 30, 2024. During the year ended December 31, 2023, no payments were made to Biogen and the Company received $ 65.7 million from Biogen for the amounts due for the three months ended December 31, 2022 and the nine months ended September 30, 2023. During the year ended December 31, 2022, no payments were made to Biogen and the Company received $ 80.3 million from Biogen for the amounts due for the three months ended December 31, 2021 and the nine months ended September 30, 2022. During the year ended December 31, 2024 , the Company recorded $ 0.9 million of other collaboration revenue related to providing development and regulatory support to Biogen in the Biogen Territory under the Biogen Collaboration Agreement. During the years ended December 31, 2023 and 2022, no other collaboration revenue was recognized related to the Biogen Collaboration Agreement. 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.

Preferred Stock

Preferred Stock	12 Months Ended
	Dec. 31, 2024
Equity [Abstract]
Preferred Stock	8. Preferred Stock The Board of Directors of the Company (the “Board”) is authorized, without action by the stockholders, to designate and issue up to an aggregate of 5,000,000 shares of preferred stock in one or more series. The Board can designate the rights, preferences and privileges of the shares of each series and any of its qualifications, limitations or restrictions. The Board may authorize the issuance of preferred stock with voting or conversion rights that could adversely affect the voting power or other rights of the holders of common stock. As of December 31, 2024 and 2023 , the Company had no shares of preferred stock issued or outstanding and preferred stock is classified within stockholders’ equity.

Common Stock

Common Stock	12 Months Ended
	Dec. 31, 2024
Text Block [Abstract]
Common Stock	9. Common Stock As of December 31, 2024 and 2023 , the Company authorized 120,000,000 shares of common stock with a par value of $ 0.0001 per share. Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders. Common stockholders are entitled to receive dividends, as may be declared by the Board, if any. As of December 31, 2024 and 2023 , no dividends have been declared. As of December 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 December 31, 2024 was $ 0.4 million. Sales Agreement On September 16, 2024, the Company entered into a Sales Agreement (the “ATM Sales Agreement”) with TD Securities (USA) LLC, as sales agent (“TD 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 TD Cowen (the “ATM Offering”). Upon the Company’s entry into the ATM Sales Agreement, the prior sales agreement with Cowen and Company, LLC, an affiliate of TD Cowen, dated November 7, 2023 (the “Original Sales Agreement”) was terminated. At the time of such termination, $ 241.7 million out of an aggregate of $ 250.0 million of shares remained unsold under the Original Sales Agreement. Upon delivery of a placement notice, and subject to the terms and conditions of the ATM Sales Agreement, TD 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 ATM Sales Agreement, but the Company has no obligation to sell any of the Shares in the ATM Offering. The Company or TD Cowen may suspend or terminate the ATM Offering upon notice to the other parties and subject to other conditions. TD 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 TD 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 ATM Sales Agreement. During the year ended December 31, 2024 the Company sold an aggregate of 700,000 shares under the Original Sales Agreement at an average price per share of $ 11.90 and received gross proceeds of approximately $ 8.3 million, before deducting commissions, underwriting discounts, and offering costs of $ 0.3 million. During the year ended December 31, 2023, the Company did no t sell any shares under the Original Sales Agreement. During the year ended December 31, 2024 , the Company did no t sell any shares under the ATM Sales Agreement. As of December 31, 2024 , $ 250.0 million of shares remain available for issuance and sale under the ATM Sales Agreement.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2024
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	10. 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 initial public offering. The 2014 Plan provided 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”). On June 10, 2024, the stockholders of the Company approved the 2024 Equity Incentive Plan (the “2024 Plan”), which had been previously approved by the Board. Upon stockholder approval, the 2024 Plan became effective immediately and replaced the 2014 Plan. The 2024 Plan provides for the grant of incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock, restricted stock units, other stock-based awards, and cash awards. The total number of shares initially reserved for issuance under the 2024 Plan is equal to the sum of (i) 5,500,000 shares of the Company’s common stock and (ii) such additional number of shares of the Company’s common stock (up to 11,002,166 shares) as is equal to the number of shares of common stock subject to awards granted under the 2014 Plan that were outstanding as of June 10, 2024, and which awards expire, terminate or are otherwise surrendered, cancelled, forfeited or repurchased by the Company at their original issuance price pursuant to a contractual repurchase right (subject, however, in the case of incentive stock options, to any limitations under the Internal Revenue Code of 1986, as amended, and any regulations thereunder). The Company no longer grants stock options or other awards under either its 2014 Plan or its 2011 Plan, and there are no stock options or other awards outstanding under the 2011 Plan. Any stock options and other awards outstanding under the 2014 Plan remain outstanding and effective in accordance with their terms. 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 December 31, 2024, the total number of shares underlying outstanding awards under the 2024 Plan, the 2014 Plan and the 2016 Plan was 8,758,214 and the total number of shares available for future issuance under the 2024 Plan was 7,490,967 shares. On July 2, 2014, the Company’s stockholders approved the 2014 Employee Stock Purchase Plan (the “ESPP”), which had been previously approved by the Board. The ESPP became effective upon the completion of the IPO. A total of 282,000 shares of common stock were authorized for issuance under the ESPP. On June 16, 2022, the Company’s stockholders approved an amendment to the ESPP to add 300,000 shares of common stock to the ESPP. On June 16, 2023, the Company’s stockholders approved an amendment to the ESPP to add 500,000 shares of common stock to the ESPP. As amended, a total of 1,082,000 shares of common stock have been authorized for issuance under the ESPP. As of December 31, 2024, 662,806 shares have been issued and 419,194 shares are available for future 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 1,338,925 $ 22.76 Vested ( 430,704 ) $ 26.32 Forfeited ( 996,225 ) $ 34.99 Outstanding as of December 31, 2024 3,000,390 $ 30.04 Time-based restricted stock units During the years ended December 31, 2024 and 2023, the Company granted 938,470 and 1,734,717 time-based restricted stock units, respectively, to its employees and consultants. During the year ended December 31, 2022, the Company did no t grant any time-based restricted stock units. During the years ended December 31, 2024, 2023 and 2022 there were 272,844 , 51,851 , and 366,014 time-based restricted stock units that vested, respectively. The fair value on the date of vesting for the years ended December 31, 2024, 2023 and 2022 was $ 2.8 million, $ 1.8 million, and $ 12.4 million, respectively. At December 31, 2024, 1,788,137 time-based restricted stock units were both outstanding and unvested, and the total unrecognized stock-based compensation expense related to these awards was $ 13.8 million, which is expected to be recognized over the remaining weighted average vesting period of 1.43 years. Performance restricted stock units During the year ended December 31, 2022, the Company granted 705,380 performance restricted stock units to its employees and consultants. The majority of these performance restricted stock units vest upon the achievement of certain clinical and regulatory development milestones related to product candidates and commercial milestones. During the year ended December 31, 2023, the Company granted 905,012 performance restricted stock units to its employees and consultants. The majority of these performance restricted stock units vest upon the achievement of certain clinical and regulatory development milestones related to product candidates and commercial milestones. Certain performance restricted stock units vest upon the Company reaching specified measures of total stockholder return. During the year ended December 31, 2024, the Company granted 400,455 performance restricted stock units to its employees. The majority of these performance restricted stock units vest upon the achievement of 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 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. During the year ended December 31, 2024, the criteria for one vesting milestone for outstanding performance restricted stock units was considered probable. The Company recognized stock-based compensation expense related to the probable vesting of this performance restricted stock unit of $ 4.0 million. There remains an estimated $ 0.4 million of expense to be recognized as of December 31, 2024. As of December 31, 2023 and 2022, for performance restricted stock units that were outstanding, and other than performance restricted stock units for which vesting is tied to total stockholder return, the achievement of the milestones that had not been met was considered not probable, and therefore no expense has been recognized related to these awards in the years ended December 31, 2023 and 2022, respectively. During the years ended December 31, 2024 and 2023, the Company recorded $ 0.8 million and $ 0.7 million, respectively, of stock-based compensation expense related to performance restricted stock units for which vesting is tied to total stockholder return. No performance restricted stock units vested during the year ended December 31, 2022. During the year ended December 31, 2023, the criteria for three vesting milestones for outstanding performance restricted stock units were achieved. The total fair value of the performance restricted stock units that vested upon achievement of these milestones was $ 9.6 million at vesting date, and the Company recognized stock-based compensation expense related to the vesting of these performance restricted stock units of $ 14.3 million. During the year ended December 31, 2024, the criteria for one vesting milestone for outstanding performance restricted stock units were achieved. The total fair value of the performance restricted stock units that vested upon achievement of this milestone was $ 1.4 million at vesting date, and the Company recognized stock-based compensation expense related to the vesting of these performance restricted stock units of $ 3.6 million. At December 31, 2024, 1,212,253 performance restricted stock units were both outstanding and unvested, and the total unrecognized stock-based compensation expense related to these awards was $ 42.9 million. Stock Option Rollforward The following table summarizes activity related to time-based and performance-based stock options: Shares Weighted Weighted Average Aggregate Outstanding as of December 31, 2023 8,118,041 $ 76.02 5.66 $ 475 Granted 2,275,745 $ 21.08 Exercised ( 10,062 ) $ 7.69 Forfeited ( 4,563,788 ) $ 79.14 Expired ( 62,112 ) $ 24.09 Outstanding as of December 31, 2024 5,757,824 $ 52.52 5.34 $ — Vested and expected to vest as of December 31, 2024 5,129,145 $ 50.56 5.17 $ — Exercisable as of December 31, 2024 4,014,487 $ 58.04 4.42 $ — As of December 31, 2024, the Company had unrecognized stock-based compensation expense related to its outstanding and unvested time-based stock option awards of $ 24.1 million, which is expected to be recognized over the remaining weighted average vesting period of 3.18 years. The intrinsic value of stock options exercised during the years ended December 31, 2024, 2023, and 2022 was $ 0.1 million, $ 1.9 million and $ 4.4 million, respectively. Performance-Based Stock Options Recognition of stock-based compensation expense associated with performance-based stock options commences when the performance condition is considered probable of achievement, using management’s best estimates, which consider the inherent risk and uncertainty regarding the future outcomes of the milestones. As of December 31, 2024, 2023 and 2022, for performance-based stock option grants that were outstanding, the achievement of the milestones that had not been met was considered not probable, and therefore no expense has been recognized related to these awards in the years ended December 31, 2024, 2023 and 2022, respectively. During the years ended December 31, 2024, 2023 and 2022, the Company granted no stock options to purchase shares of common stock that contain performance-based vesting criteria. During the years ended December 31, 2024 and 2022, no milestones were achieved under performance-based stock options. During the year ended December 31, 2023, the criteria for one regulatory development milestone was achieved under performance-based stock options granted in connection with the hiring of its chief executive officer . During the year ended December 31, 2023, the Company recognized stock-based compensation expense related to this milestone of $ 10.7 million. As of December 31, 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 years ended December 31, 2024, 2023, and 2022: Year Ended December 31, 2024 2023 2022 (in thousands) Research and development $ 18,885 $ 24,813 $ 25,888 Selling, general and administrative 35,587 47,716 35,714 Restructuring 32 838 — $ 54,504 $ 73,367 $ 61,602 The stock-based compensation expense of $ 32 thousand is related to the restructuring during the year ended December 31, 2024 and represents the incremental amount related to modifying the exercise period for outstanding, vested stock option grants that had been granted to employees whose employment was terminated in the restructuring. The expense was recorded within the restructuring expenses on the consolidated statements of operations and comprehensive loss. The stock-based compensation expense of $ 0.8 million is related to the restructuring during the year ended December 31, 2023 and represents the incremental amount related to modifying the exercise period for outstanding, vested stock option grants that had been granted to employees whose employment was terminated in the restructuring. The expense was recorded within the restructuring expenses on the consolidated statements of operations and comprehensive loss. The following table summarizes stock-based compensation expense by award type recognized during the years ended December 31, 2024, 2023, and 2022: Year Ended December 31, 2024 2023 2022 (in thousands) Stock options $ 26,609 $ 47,695 $ 54,971 Restricted stock units 27,058 24,424 5,587 Employee stock purchase plan 837 1,248 1,044 $ 54,504 $ 73,367 $ 61,602 For stock option awards, the fair value is estimated at the grant date using the Black-Scholes option-pricing model, taking into account the terms and conditions upon which stock options are granted. For grants with service based vesting conditions, the fair value of the stock options is amortized on a straight-line basis for stock option awards to employees, non-employee directors and non-employee consultants over the requisite service period of the awards. The weighted average grant date fair value per share of stock options granted under the Company’s stock option plans during the years ended December 31, 2024, 2023, and 2022 was $ 14.23 , $ 29.53 and $ 25.96 , respectively. The fair value of each stock option granted under the Company’s equity plans has been calculated on the date of grant using the following weighted average assumptions: Year Ended December 31, 2024 2023 2022 Expected dividend yield 0 % 0 % 0 % Expected volatility 76 % 72 % 73 % Risk-free interest rate 4.24 % 3.85 % 2.49 % Expected term 6.01 years 6.01 years 6.03 years Expected dividend yield: the Company has not paid, and does not anticipate paying, any dividends in the foreseeable future. Risk-free interest rate: the Company determined the risk-free interest rate by using a weighted average equivalent to the expected term based on the U.S. Treasury yield curve in effect as of the date of grant. Expected volatility: the Company uses the historical volatility of its publicly traded common stock, as there is adequate historical data for the duration of the expected term. Expected term (in years): the expected term represents the period that the Company’s stock option grants are expected to be outstanding. The expected term of the stock options granted to employees, non-employee directors and non-employee consultants by the Company has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” stock options. Under this approach, the weighted average expected life is presumed to be the average of the vesting term and the contractual term of the stock option. This approach is used because the Company does not have sufficient historical exercise data to provide a reasonable basis upon which to estimate the expected term due to the limited period of time that its stock has been publicly traded. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from estimates. The Company estimates forfeitures based on historical terminations. For the years ended December 31, 2024, 2023, and 2022, the weighted-average forfeiture rates were 15.1 % , 16.6 % and 19.2 % , respectively.

Net Loss Per Share

Net Loss Per Share	12 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
Net Loss Per Share	11. Net Loss Per Share The following table shows the calculation of basic and diluted net loss per share for the years ended December 31, 2024, 2023, and 2022: Year Ended December 31, 2024 2023 2022 Basic net loss per share: Numerator: Net loss (in thousands) $ ( 400,666 ) $ ( 541,489 ) $ ( 532,784 ) Denominator: Weighted average common stock outstanding 60,765,913 59,836,441 59,306,094 Net loss per share - basic and diluted $ ( 6.59 ) $ ( 9.05 ) $ ( 8.98 ) The following table summarizes potential dilutive securities outstanding at the end of each reporting period that were excluded from the calculation of diluted net loss per share because including them would have been anti-dilutive as of December 31, 2024, 2023, and 2022: Year Ended December 31, 2024 2023 2022 Stock options 5,302,824 7,663,041 7,138,350 Restricted stock units 1,788,137 1,662,363 160,403 Employee stock purchase plan 52,436 61,402 76,105 7,143,397 9,386,806 7,374,858 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.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2024
Income Tax Disclosure [Abstract]
Income Taxes	12. Income Taxes Loss before income tax expense consists of the following: Year Ended December 31, 2024 2023 2022 (in thousands) Domestic $ ( 401,549 ) $ ( 541,656 ) $ ( 532,539 ) Foreign 883 167 ( 245 ) $ ( 400,666 ) $ ( 541,489 ) $ ( 532,784 ) There is no current or deferred provision for income taxes because the Company has historically incurred and utilized operating losses prior to the year ended December 31, 2024. As of December 31, 2024, the Company continues to maintain a full valuation allowance against its net deferred tax assets. The reported amount of income tax expense for the years differs from the amount that would result from applying domestic federal statutory tax rates to pretax losses primarily because of changes in the valuation allowance. A reconciliation of the U.S. statutory rate to the Company’s effective tax rate is as follows: Year Ended December 31, 2024 2023 2022 Tax due at statutory rate 21.0 % 21.0 % 21.0 % State taxes, net of federal 1.9 4.1 1.8 Stock-based compensation ( 10.2 ) ( 1.7 ) ( 1.9 ) Federal and state tax credits 2.9 2.4 2.1 Change in valuation allowance ( 15.4 ) ( 26.2 ) ( 23.0 ) Other ( 0.2 ) 0.4 — 0.0 % 0.0 % 0.0 % For the year ended December 31, 2024, the impact from stock-based compensation on the Company’s effective tax rate was primarily caused by cancellations of vested non-qualified stock options. Significant components of the Company’s net deferred tax assets at December 31, 2024 and 2023 are as follows: December 31, 2024 2023 (in thousands) Net operating losses $ 490,891 $ 428,785 Tax credits 145,113 133,602 Capitalized research and development expenses 128,001 110,690 Stock-based compensation 23,967 53,860 Accrued expenses 5,491 7,018 Depreciation and amortization 1,914 1,456 Lease liability 2,748 1,207 Right of use asset ( 2,497 ) ( 1,042 ) Other 1,090 ( 382 ) Total net deferred tax asset before valuation 796,718 735,194 Valuation allowance ( 796,718 ) ( 735,194 ) $ — $ — On August 16, 2022, the Inflation Reduction Act of 2022 (the “IRA”) was signed into law. The IRA introduced new tax provisions, including a 15.0 % corporate alternative minimum tax and a 1.0 % excise tax on stock repurchases. The provisions of the IRA are effective for periods after December 31, 2022. The enactment of the IRA did not result in any material adjustments to the Company’s income tax provision or net deferred tax assets as of December 31, 2024 and 2023. As of December 31, 2024, the Company had federal net operating loss carryforwards of $ 2.0 billion, of which $ 30.4 million begin to expire in 2033 and the remainder do not expire but are subject to 80 % limitation. As of December 31, 2024, the Company had state net operating loss carryforwards of $ 1.1 billion that begin to expire in 2033 . As of December 31, 2024, the Company had federal and state research and development tax credits carryforwards of $ 90.5 million and $ 18.4 million, respectively, which begin to expire in 2031 and 2032 , respectively. As of December 31, 2024, the Company had federal orphan drug tax credit carryforwards of $ 40.1 million, which begin to expire in 2034 . As of December 31, 2024, net deferred tax assets before the valuation allowance increased $ 61.5 million, primarily due to the capitalization of research and development expenses and the increase of federal and state net operating loss carryforwards due to the loss generated for the year ended December 31, 2024, offset by the cancelation of vested nonqualified stock options resulting from the workforce reductions during the years ended December 31, 2024 and 2023. This increase in net deferred tax assets was offset by a corresponding increase in the valuation allowance. Management of the Company has evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets, which are comprised principally of federal and state net operating loss, capitalized research and development expenses and tax credit carryforwards. Under the applicable accounting standards, management has considered the Company’s history of losses and concluded that it is more likely than not that the Company will not recognize the benefits of its federal and state deferred tax assets. Accordingly, a full valuation allowance of $ 796.7 million and $ 735.2 million has been established at December 31, 2024 and 2023, respectively. The valuation allowance increased by $ 61.5 million for the year ended December 31, 2024, primarily due to the capitalization of research and development expenses and generation of net operating losses, offset by the cancelation of vested nonqualified stock options. The valuation allowance increased by $ 141.9 million and $ 122.7 million for the years ended December 31, 2023 and 2022, respectively, primarily due to the capitalization of research and development expenses and generation of net operating losses. Pursuant to Section 382 of the Internal Revenue Code of 1986, as amended, (the “Code”), and similar state tax law, certain substantial changes in the Company’s ownership may result in a limitation on the amount of net operating loss and tax credit carryforwards that may be used in future years. Utilization of the net operating loss and tax credit carryforwards may be subject to a substantial annual limitation under Section 382 of the Code, due to ownership change limitations that have occurred previously or that could occur in the future. These ownership changes may limit the amount of net operating loss and tax credit carryforwards that can be utilized annually to offset future taxable income and tax, respectively. The Company completed a Section 382 study through December 31, 2020. Based on the study, the Company underwent two ownership changes for Section 382 purposes which occurred on March 11, 2014 and December 31, 2015. As a result of the ownership changes, the Company’s net operating loss and tax credit carryforwards as of the ownership change dates are subject to limitation under Section 382; however, these limitations are not expected to cause any of the impacted net operating loss and tax credit carryforwards to expire unused. Subsequent ownership changes, as defined by Section 382, may potentially further limit the amount of net operating loss and tax credit carryforwards that could be utilized to offset future taxable income and tax. The Company applies the authoritative guidance on accounting for and disclosure of uncertainty in tax positions, which requires the Company to determine whether a tax position of the Company is more likely than not to be sustained upon examination, including resolution of any related appeals of litigation processes, based on the technical merits of the position. For tax positions meeting the more likely than not threshold, the tax amount recognized in the financial statements is reduced by the largest benefit that has a greater than fifty percent likelihood of being realized upon the ultimate settlement with the relevant taxing authority. The following table reconciles the beginning and ending amounts of gross unrecognized tax benefits, excluding interest and penalties, if any, for the years ended December 31, 2024, 2023, and 2022: 2024 2023 2022 (in thousands) Balance as of January 1 $ 7,743 $ 6,846 $ 6,084 Increases related to current year tax positions 520 655 697 Increases related to prior year tax positions 15 242 65 Balance as of December 31 $ 8,278 $ 7,743 $ 6,846 For the years ended December 31, 2024, 2023, and 2022, the increases in unrecognized tax benefits related to current year and prior year tax positions with respect to the Company’s federal and state tax credits. The Company’s policy is to record interest and penalties related to income taxes as part of the tax provision. As of December 31, 2024 and 2023 , the Company had no accrued interest or penalties related to income taxes and no amounts have been recognized in the Company’s statements of operations and comprehensive loss for the years ended December 31, 2024, 2023, and 2022. The Company files tax returns as prescribed by the tax laws of the jurisdictions in which it operates. In the normal course of business, the Company is subject to examination by federal, state and foreign jurisdictions, where applicable. There are currently no pending tax examinations, and the Company’s tax returns are generally open under statute from 2021 to the present. Tax attributes such as net operating losses and tax credits generated prior to 2021 and utilized in open years may still be adjusted upon examination.

Employee Benefit Plan

Employee Benefit Plan	12 Months Ended
	Dec. 31, 2024
Postemployment Benefits [Abstract]
Employee Benefit Plan	13. Employee Benefit Plan The Company maintains a 401(k) profit sharing plan (the “ 401(k) Plan ”) for its employees. Each employee may elect to contribute a portion of his or her compensation to the 401(k) Plan, subject to annual limits established by the Internal Revenue Service. For the years ended December 31, 2024, 2023, and 2022 , the Company matched 50 % of eligible contributions to the 401(k) Plan up to 6 % of employee contributions. For the years ended December 31, 2024, 2023, and 2022 the Company contributed $ 2.9 million, $ 3.9 million, and $ 3.0 million, respectively, to the 401(k) Plan.

Restructuring

Restructuring	12 Months Ended
	Dec. 31, 2024
Restructuring and Related Activities [Abstract]
Restructuring	14. Restructuring In August 2023, the Company implemented a strategic corporate reorganization and reprioritization of its pipeline (the “2023 Restructuring”). The 2023 Restructuring included a reduction of the Company’s workforce by approximately 40 %, designed to right-size the organization as the Company worked to achieve sustained growth and support the commercialization of ZURZUVAE for the treatment of women with PPD. During the year ended December 31, 2023, the Company recorded $ 33.4 million of expense related to the 2023 Restructuring, primarily for one-time termination benefits to the affected employees, primarily for cash payments of severance, healthcare benefits and outplacement assistance. As of December 31, 2024, the Company has paid substantially all of the accrued 2023 Restructuring charges and during the year ended December 31, 2024, the Company recorded a $ 0.5 million reversal of related expense. Total restructuring charges incurred through December 31, 2024 are $ 32.9 million, which is the total expected amount to be incurred. In October 2024, the Company implemented a plan to reorganize its business operations (the “2024 Restructuring”), including to focus investment on the ongoing launch of ZURZUVAE for the treatment of women with PPD and its prioritized pipeline development efforts. As part of the 2024 Restructuring, the Company implemented a reduction of approximately 33 % of the Company’s total workforce and approximately 55 % of the Company’s research and development workforce. During the year ended December 31, 2024, the Company recorded $ 22.3 million of expense for the 2024 Restructuring, primarily for one-time termination benefits to the affected employees, primarily consisting of cash payments of severance, healthcare benefits and outplacement assistance. The Company expects that substantially all of the accrued 2024 Restructuring charges as of December 31, 2024 will be paid in cash by June 30, 2025. The Company expects to incur a total of $ 23.6 million of expense related to the 2024 Restructuring, including $ 1.3 million of expense which will be recorded in future periods, primarily consisting of one-time termination benefits. The following table summarizes activity related to the restructuring accrual inclusive of both the 2023 and 2024 Restructuring: Year Ended December 31, 2024 2023 (in thousands) Balance as of January 1 $ 10,589 $ — Restructuring expenses incurred, net 21,854 33,386 Cash paid ( 16,939 ) ( 19,163 ) Non-cash activity ( 197 ) ( 3,634 ) Balance as of December 31 $ 15,307 $ 10,589

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2024
Segment Reporting [Abstract]
Segment Information	15. Segment Information Operating segments are defined as components of an entity for which separate financial information is available and that is regularly reviewed by the Chief Operating Decision Maker (“CODM”) in deciding how to allocate resources to an individual segment and in assessing performance. The Company operates as a single reporting segment, focused on discovering, developing and delivering brain health medicines. The Company’s measure of segment profit or loss is net loss. The CODM is the chief executive officer (“CEO”). The CODM manages and allocates resources to the operations of the Company on a total company basis. Managing and allocating resources on a consolidated basis enables the CEO to assess the overall level of resources available and how to best deploy these resources across functions, therapeutic areas and research and development projects that are in line with the Company’s long-term company-wide strategic goals. Consistent with this decision-making process, the CEO uses consolidated financial information for purposes of evaluating performance, forecasting future period financial results, allocating resources and setting incentive targets. Operating expenses are used to monitor budget versus actual results. The CODM also uses net loss in competitive analysis by benchmarking to the Company’s peer group. The competitive analysis along with the monitoring of budgeted versus actual results are used in assessing performance of the segment. All the Company’s long-lived assets are held in the United States and all the Company’s revenues are derived from the United States. The following table is representative of the significant expense categories regularly provided to the CODM when managing the Company’s single reporting segment. A reconciliation to the consolidated net loss for the years ended December 31, 2024, 2023 and 2022 is included at the bottom of the table below. Year Ended December 31, 2024 2023 2022 (in thousands) Revenues $ 41,243 $ 86,455 $ 7,686 Cost of revenues 9,444 2,159 813 Program expenses (1) ZULRESSO 5,101 4,395 17,083 zuranolone (ZURZUVAE) 30,482 94,174 68,155 SAGE-324 10,173 16,574 14,646 dalzanemdor (SAGE-718) 58,248 56,536 50,584 Other research and development programs 33,277 52,975 49,750 Non-program expenses (2) 85,405 113,388 96,825 People and staff augmentation 165,158 220,188 195,214 Restructuring 21,854 33,386 — Other segment items (3) 22,767 34,169 47,400 Net loss $ ( 400,666 ) $ ( 541,489 ) $ ( 532,784 ) (1) Includes external research and development, and selling, general and administrative expenses. (2) Includes information technology, infrastructure, facilities, legal, commercial data and systems, chemistry platform, intellectual property, and other general and administrative expense. (3) Includes stock-based compensation expense, interest income, and other (income) expense.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2024
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On January 10, 2025, the Company received an unsolicited, non-binding acquisition proposal from Biogen to acquire all outstanding shares of the Company not already owned by Biogen for $ 7.22 per share. On January 27, 2025, the Board of Directors (the “Board”) unanimously rejected the unsolicited, non-binding acquisition proposal received from Biogen. The Company further announced that the Board has initiated a process to explore strategic alternatives for the Company. On January 16, 2025, the Company commenced litigation against Biogen in the Delaware Court of Chancery seeking declaratory, injunctive and other relief. In its complaint, the Company alleges that Biogen breached the standstill provision in the Biogen Stock Purchase Agreement by making an unsolicited acquisition proposal and related public disclosures. See Note 6, Commitments and Contingencies , for further details.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 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 authorities prior to commercial sales. There can be no assurance that the current and future product candidates of the Company will receive, or that 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, 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 Inc. (“Biogen”) (the “Biogen Collaboration Agreement”). As of December 31, 2024, the Company had an accumulated deficit of $ 3.0 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 consolidated financial statements. At some point after that time, the Company anticipates it will require additional financing to fund its future operations. Even if the Company believes it has sufficient funds for its current or future operating plans, the Company may seek to raise additional capital if market conditions are favorable or in light of other strategic considerations.
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements include those of the Company and its subsidiaries after elimination of all intercompany accounts and transactions. The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the U.S. (“GAAP”).
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. Intercompany accounts and transactions have been eliminated.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period.
Cash Equivalents	Cash Equivalents The Company considers all highly liquid investments with an original maturity of 90 days or less to be cash equivalents. As of December 31, 2024, cash equivalents were comprised of money market funds, U.S. government securities, and U.S. commercial paper. As of December 31, 2023 , cash equivalents were comprised of money market funds and U.S. government securities.
Marketable Securities	Marketable Securities Marketable securities consist of investments with original maturities greater than 90 days. The Company has classified its investments with maturities beyond one year as short-term, based on their highly liquid nature and because such marketable securities represent the investment of cash that is available for current operations. The Company considers its investment portfolio of marketable securities to be available-for-sale. Accordingly, these investments are recorded at fair value, which is based on quoted market prices. Unrealized gains and losses are reported as the accumulated other comprehensive items in stockholders’ equity. When the fair value is below the amortized cost of the asset, an estimate of expected credit losses is made. The credit-related impairment amount is recognized in net income (loss); the remaining impairment amount and unrealized gains are reported as a component of accumulated other comprehensive items in stockholders’ equity. Credit losses are recognized through the use of an allowance for credit losses account and subsequent improvements in expected credit losses are recognized as a reversal of an amount in the allowance for credit losses account. If the Company has the intent to sell the security or it is more likely than not that the Company will be required to sell the security prior to recovery of its amortized cost basis, then the allowance for the credit loss is written-off and the excess of the amortized cost basis of the asset over its fair value is recorded in the consolidated statements of operations and comprehensive loss. Regardless of the Company’s intent to sell a security, it performs additional analysis on all securities with unrealized losses to evaluate losses associated with the creditworthiness of the security. Credit losses are identified where the Company does not expect to receive cash flows sufficient to recover the amortized cost basis of a security. The Company adjusts the cost of available-for-sale debt securities for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion are included in interest income. The cost of securities sold is based on the specific identification method. The Company includes interest and dividends on securities classified as available-for-sale in interest income.
Accounts Receivable	Accounts Receivable The Company’s trade accounts receivable consist of amounts due from specialty distributors and specialty pharmacies that have been certified under a Risk Evaluation and Mitigation Strategy program in the U.S. related to sales of ZULRESSO and have standard payment terms that generally require payment within 30 to 90 days from the invoice date. The Company monitors the financial performance and creditworthiness of customers so that it can properly assess and respond to changes in their credit profiles. The Company makes judgments as to its ability to collect outstanding receivables and provides an allowance for bad debts against the trade account receivables, when appropriate. As of December 31, 2024 and 2023, trade accounts receivable were $ 0.4 million and $ 1.4 million, respectively, and are included in prepaid expenses and other current assets on the consolidated balance sheets. As of December 31, 2024 , the Company has not provided any allowance for bad debts against the trade accounts receivable.
Inventory	Inventory Prior to the initial date that regulatory approval is received for a product candidate of the Company, costs related to the production of inventory are recorded as research and development expense on the Company’s consolidated statements of operations and comprehensive loss in the period incurred. Inventory is stated at the lower of cost or estimated net realizable value with cost determined on a first-in, first-out basis. Inventory costs may include purchases of raw materials, third-party contract manufacturing services, third-party packaging services, salary related expenses, overhead costs, and freight. Raw and intermediate materials that may be utilized for either research and development or commercial purposes, after approval of the product by the FDA, are classified as inventory. Amounts in inventory that are used for research and development purposes are charged to research and development expense when the product enters the research and development process and can no longer be used for commercial purposes and, therefore, does not have an “alternative future use” as defined in authoritative guidance. The Company performs an assessment of the recoverability of capitalized inventory during each reporting period and, if needed, writes down any excess and obsolete inventory to its estimated net realizable value in the period it is identified. If they occur, such impairment charges are recorded as a component of cost of revenues in the consolidated statements of operations and comprehensive loss. As of December 31, 2024 , the Company did no t have any capitalized inventory on hand. As of December 31, 2023, inventory was $ 1.5 million, and is included in prepaid expenses and other current assets on the consolidated balance sheets.
Property and Equipment	Property and Equipment Property and equipment are recorded at cost and depreciated over their estimated useful lives using the straight-line method. Upon retirement or sale, the cost of assets disposed of and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is credited or charged to the Company’s consolidated statements of operations and comprehensive loss. Repairs and maintenance costs are expensed as incurred.
Leases	Leases The Company determines if an arrangement is a lease at contract inception. Operating lease assets represent the Company’s right to use an underlying asset for the lease term and operating lease liabilities represent the Company’s obligation to make payments arising from the lease. Operating lease assets and liabilities are recognized at the commencement date of the lease based upon the present value of lease payments over the lease term. When determining the lease term, the Company includes options to extend or terminate the lease when it is reasonably certain that the Company will exercise those options. The Company uses the Company’s incremental borrowing rate when the implicit interest rate is not readily determinable based upon the information available at the commencement date of the lease in determining the present value of the lease payments and the implicit interest rate when readily determinable. The lease payments used to determine the Company’s operating lease assets may include lease incentives, stated rent increases and escalation clauses linked to rates of inflation, when determinable, and are recognized in the Company’s operating lease assets in the Company’s consolidated balance sheets. In addition, the Company’s contracts may contain lease and non-lease components. The Company combines lease and non-lease components, which are accounted for together as lease components. The Company’s operating leases are reflected in the right-of-use operating asset; operating lease liability, current portion; and operating lease liability, net of current portion in the Company’s consolidated balance sheets. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. Short-term leases, defined as leases that have a lease term of 12 months or less at the commencement date, are not recorded on the Company’s consolidated balance sheets and are recognized in the consolidated statements of operations and comprehensive loss on a straight-line basis over the term of the lease. Variable lease payments are the amounts owed by the Company to a lessor that are not fixed, such as reimbursement for common area maintenance and utilities costs for facility leases. Variable lease payments are expensed when incurred.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets Long-lived assets consist of property and equipment and lease right-of-use assets. Long-lived assets to be held and used are tested for recoverability whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends, and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long-lived asset group for recoverability, the Company compares forecasts of undiscounted cash flows expected to result from the use and eventual disposition of the long-lived asset group to its carrying value. The impairment loss would be based on the excess of the carrying value of the impaired asset over its fair value, determined based on discounted cash flows. During the year ended December 31, 2024 , the Company recorded $ 2.2 million of impairment losses on long-lived assets as a result of discontinuing the commercial availability of ZULRESSO. During the year ended December 31, 2023 , the Company did not record any impairment losses on long-lived assets.
Cost of Revenues	Cost of Revenues Cost of revenues includes direct and indirect costs related to the manufacturing and distribution of ZULRESSO, including third-party contract manufacturing costs, packaging services, freight, third-party royalties payable on the Company’s net product revenue of ZULRESSO and amortization of intangible assets associated with ZULRESSO. Cost of revenues also includes our proportionate share of ZURZUVAE manufacturing costs under the Biogen Collaboration Agreement, (for additional information, refer to Note 7, Collaboration Agreements ). Cost of revenues may also include period costs related to certain inventory manufacturing services and inventory adjustment charges. Prior to receiving FDA approval of ZULRESSO in March 2019 and ZURZUVAE in August 2023, the Company manufactured inventory in preparation for launch. As a result, certain manufacturing costs associated with revenues were expensed prior to FDA approval and, therefore, a portion of such costs are not included in cost of revenues during the years ended December 31, 2024, 2023, and 2022 .
Research and Development Costs and Accruals	Research and Development Costs and Accruals Research and development expenses are comprised of costs incurred in performing research and development activities, including salaries and benefits, overhead costs, depreciation, contract services and other related costs. Research and development costs are expensed to operations as the related obligation is incurred. The Company has entered into various research and development contracts with research institutions and other companies both inside and outside of the U.S. These agreements are generally cancelable, and related costs are recorded as research and development expenses as incurred. The Company records accruals for estimated ongoing research and development costs. When billing terms under these contracts do not coincide with the timing of when the work is performed, the Company is required to make estimates of outstanding obligations to those third parties as of the end of the reporting period. Any accrual estimates are based on a number of factors, including the Company’s knowledge of the progress towards completion of the research and development activities, invoicing to date under the contracts, communication from the research institution or other companies of any actual costs incurred during the period that have not yet been invoiced, and the costs included in the contracts. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from the estimates made by the Company. The historical accrual estimates made by the Company have not been materially different from the actual costs.
Stock-Based Compensation	Stock-Based Compensation The Company recognizes stock-based compensation expense for grants under our equity incentive plans and employee stock purchase plan. The Company accounts for all stock-based awards granted to employees at their fair value and recognize compensation expense over the vesting period of the award. Determining the amount of stock-based compensation to be recorded requires the Company to develop estimates of fair values of stock options as of the grant date. The Company calculates the grant date fair values of stock options using the Black-Scholes valuation model, which requires the input of subjective assumptions, including but not limited to expected stock price volatility over the term of the awards, the expected term of stock options and the expected forfeiture rate. The fair value of restricted stock awards granted to employees is based upon the quoted closing market price per share on the date of grant. The Company has performance conditions included in certain of its performance restricted stock units that are based upon the achievement of pre-specified clinical development, regulatory, commercial and/or financial performance events. As the outcome of each event has inherent risk and uncertainties, and a positive outcome may not be known until the event is achieved, the Company begins to recognize the value of the performance-based restricted stock awards when the Company determines the achievement of each performance condition is deemed probable, a determination which requires significant judgment by management. At the probable date, the Company records estimated cumulative expense to date, with remaining expense amortized over the remaining service period until achievement has occurred.
Treasury Stock	Treasury Stock The Company records treasury stock at cost. Treasury stock consists of shares of the Company’s common stock received from a then-employee as consideration for exercises of stock options.
Basic and Diluted Net Loss Per Share	Basic and Diluted Net Loss Per Share Basic net loss per share is computed by dividing the net loss by the weighted average number of common shares outstanding for the period. For periods in which the Company has reported net losses, diluted net loss per share is the same as basic net loss per share, because dilutive common shares are not assumed to have been issued if their effect is antidilutive. The Company reported a net loss for the years ended December 31, 2024, 2023 and 2022.
Concentration of Credit Risk and of Significant Suppliers	Concentration of Credit Risk and of Significant Suppliers Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash, cash equivalents and marketable securities. The Company maintains accounts for all cash and cash equivalents at accredited financial institutions, and consequently, the Company believes that such funds are subject to minimal credit risk. The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. The Company’s marketable securities, which primarily consist of U.S. government agency securities and treasuries, corporate bonds and commercial paper, potentially subject the Company to concentrations of credit risk. The Company has adopted an investment policy that limits the amounts the Company may invest in any one type of investment, defines allowable investments, and requires all investments held by the Company to minimum credit rating standards, thereby reducing credit risk exposure. The Company has no significant off-balance sheet concentrations of credit risk, such as foreign currency exchange contracts, option contracts, or other hedging arrangements . The Company is dependent on third-party manufacturers to supply products for research and development activities for its programs. The Company also relies on and expects to continue to rely on third-party manufacturers to supply it with active pharmaceutical ingredients (“API”) and formulated drugs; and to provide other services related to manufacturing activities for these programs. These programs could be adversely affected by a significant interruption in the supply of API and formulated drugs, or the interruption of manufacturing related services.
Income Taxes	Income Taxes The Company accounts for income taxes under the asset and liability method. Under this method, deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted rates in effect for the year in which these temporary differences are expected to be recovered or settled. Valuation allowances are provided if, based on the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company accounts for uncertain tax positions in accordance with the provisions of Accounting Standards Codification (“ASC”) Topic 740, “ Income Taxes ”. When uncertain tax positions exist, the Company recognizes the tax benefit of tax positions to the extent that the benefit will more likely than not be realized. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. The Company accrues for potential interest and penalties related to unrecognized tax benefits in income tax expense.
Fair Value Measurements	Fair Value Measurements Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Financial assets and liabilities carried at fair value are classified and disclosed in one of the following three categories: Level 1 — Quoted market prices in active markets for identical assets or liabilities. Level 2 — Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The Company’s cash equivalents and marketable securities at December 31, 2024 and 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 consolidated balance sheets for the collaboration receivable – related party, accounts payable, and accrued expenses approximate their fair values due to their short-term maturities at December 31, 2024 and 2023 , respectively.
Comprehensive Income (Loss)	Comprehensive Income (Loss) Comprehensive loss includes net loss and other changes in stockholders’ equity that result from transactions and economic events other than those with stockholders. The Company’s only element of other comprehensive income (loss) is unrealized gains and losses on marketable securities that are considered to be available-for-sale.
Revenue Recognition	Revenue Recognition Under ASC Topic 606, Revenue from Contracts with Customers (“Topic 606”), an entity recognizes revenue when or as performance obligations are satisfied by transferring control of promised goods or services to a customer, in an amount that reflects the consideration that the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of Topic 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price, including variable consideration, if any; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. Arrangements that include rights to additional goods or services that are exercisable at a customer’s discretion are generally considered options. The Company assesses if these options provide a material right to the customer and if so, they are considered performance obligations. The exercise of a material right may be accounted for as a contract modification or as a continuation of the contract for accounting purposes. Topic 606 applies to all contracts with customers, except for contracts that are within the scope of other standards, such as collaboration arrangements. For contracts determined to be within the scope of Topic 606, the Company assesses whether the goods or services promised within each contract are distinct to identify those that are performance obligations. This assessment involves subjective determinations and requires management to make judgments about the individual promised goods or services and whether such are separable from the other aspects of the contractual relationship. Promised goods and services are considered distinct provided that: (i) the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer and (ii) the entity’s promise to transfer the good or service to the customer is separately identifiable from other promises in the contract. The Company allocates the transaction price (the amount of consideration it expects to be entitled to from a customer in exchange for the promised goods or services) to each performance obligation and recognizes the associated revenue when (or as) each performance obligation is satisfied. The Company’s estimate of the transaction price for each contract includes all variable consideration to which the Company expects to be entitled. Product Revenue, Net Until the discontinuation of commercial availability of ZULRESSO as of December 31, 2024, the Company generated product revenue from the sale of ZULRESSO to a limited number of specialty distributors and specialty pharmacy providers in the U.S. The Company recognized product revenue, net of variable consideration related to certain allowances and accruals that are determined using the expected value method, in its consolidated financial statements at the point in time when control transfers to the customer, which was 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 was to deliver the product to the location specified by the customer’s order. The Company records shipping and handling costs associated with delivery of product to its customers within selling, general and administrative expenses on its consolidated statements of operations and comprehensive loss. The Company expenses incremental costs of obtaining a contract as incurred if the expected amortization period of the asset would be less than one year. If the Company were to incur incremental costs with an amortization period greater than a year, such costs would be capitalized as contract assets, as they are expected to be recovered, and would be expensed by amortizing on a systematic basis that is consistent with the transfer to the customer of the goods or services to which the asset relates. The Company did not have any contract assets (unbilled receivables) at December 31, 2024, as customer invoicing generally occurs before or at the time of revenue recognition. The Company did not have any contract liabilities at December 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 consolidated balance sheets. As of December 31, 2024 and 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 ZULRESSO sold by the Company during the reporting period, as well as its estimate of product that remains in the distribution channel inventory of its customers at the end of the reporting period. On a quarterly basis, the Company updates its estimates, if necessary, and records any material adjustments in the period they are identified. Chargebacks : The Company estimates chargebacks from its customers who directly purchase the product from the Company for discounts resulting from contractual commitments to sell products to eligible healthcare settings at prices lower than the list prices charged to its customers. Customers charge the Company for the difference between what they pay to the Company for the product and the selling price to the eligible healthcare settings. Reserves for chargebacks consist of credits that the Company expects to issue for units that remain in the distribution channel inventories at the end of each reporting period that the Company expects will be sold to eligible healthcare settings, and chargebacks that customers have claimed, but for which the Company has not yet issued a credit. Government Rebates : The Company is subject to discount obligations under government programs, including Medicaid. The Company records reserves for rebates in the same period the related product revenue is recognized, resulting in a reduction of ZULRESSO product revenue and a current liability that is included in accrued expenses on its consolidated balance sheets. The Company’s liability for these rebates consists of invoices received for claims from prior quarters that have not been paid or for which an invoice has not yet been received, estimates of claims for the current quarter, and estimates of future claims that will be made for product that has been recognized as revenue, but which remains in the distribution channel at the end of each reporting period. Trade Discounts and Allowances : The Company generally provides customary invoice discounts on ZULRESSO sales to its customers for prompt payment and the Company pays fees for sales order management, data, and distribution services. The Company estimates its customers will earn these discounts and fees and deducts these discounts and fees in full from gross ZULRESSO revenue and accounts receivable at the time the Company recognizes the related revenue. Financial Assistance : The Company provides voluntary financial assistance programs for ZULRESSO to patients with commercial insurance that have coverage and reside in states that allow financial assistance. The Company estimates the financial assistance amounts for ZULRESSO and records any such amounts within accrued expenses on its consolidated balance sheets. The calculation of the accrual for financial assistance is based on an estimate of claims and the cost per claim that the Company expects to receive using demographics for patients who have registered and been approved for assistance. Any adjustments are recorded in the same period the related revenue is recognized, resulting in a reduction of product revenue and the establishment of a current liability, which is included as a component of accrued expenses on the consolidated balance sheets. Product Returns : Consistent with industry practice, the Company offers product return rights with respect to ZULRESSO to customers for damaged, defective or expiring product, provided it is within a specified period around the product expiration date as set forth in the Company’s return goods policy. The Company estimates the amount of its product sales that may be returned by its customers and records this estimate as a reduction of revenue in the period the related product revenue is recognized, as well as a reserve within accrued expenses on the consolidated balance sheets. Product returns have 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, Collaborative Arrangements (“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 Topic 808. This assessment is performed throughout the life of the arrangement based on changes in the responsibilities of all parties in the arrangement. For collaboration arrangements within the scope of Topic 808 that contain multiple elements, the Company first determines which elements of the collaboration are deemed to be within the scope of Topic 808 and which elements of the collaboration are more reflective of a vendor-customer relationship and therefore within the scope of Topic 606. For elements of collaboration arrangements that are accounted for pursuant to Topic 808, an appropriate recognition method is determined and applied consistently, either by analogy to authoritative accounting literature or by applying a reasonable and rational policy election. For those elements of the arrangement that are accounted for pursuant to Topic 606, the Company applies the five-step model described above and presents the arrangement as license and milestone revenue or other collaboration revenue in the consolidated statements of operations and comprehensive loss. For collaboration arrangements that are within the scope of Topic 808, the Company evaluates the income statement classification for presentation of amounts due from or owed to other participants associated with multiple activities in a collaboration arrangement based on the nature of each separate activity. Payments or reimbursements that are the result of a collaborative relationship instead of a vendor-customer relationship are recorded as an increase to collaboration revenue, an increase to or reduction of cost of revenues, research and development expense or selling, general and administrative expense, depending on the nature of the activity. For additional information relating to the accounting for the co-commercialization of ZURZUVAE in the U.S. with Biogen under Topic 808, refer to Note 7, Collaboration Agreements. Recently Adopted Accounting Pronouncements In November 2023, the Financial Accounting Standards Board (“FASB”) issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures (“ASU 2023-07”). ASU 2023-07 requires disclosure of incremental segment information on an annual and interim basis. The amendments also require companies with a single reportable segment to provide all disclosures required by this amendment and all existing segment disclosures in ASC 280, Segment Reporting. The amendments are effective for fiscal years beginning after December 15, 2023, and interim periods beginning after December 15, 2024. The Company adopted ASU 2023-07 , effective December 31, 2024 , in these consolidated financial statements. ASU 2023-07 only impacted the disclosures and did not impact the consolidated financial statements. See Note 15, Segment Information , for disclosures related to the adoption of ASU 2023-07.
Recently Adopted and Issued Accounting Pronouncements	Recently Adopted Accounting Pronouncements In November 2023, the Financial Accounting Standards Board (“FASB”) issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures (“ASU 2023-07”). ASU 2023-07 requires disclosure of incremental segment information on an annual and interim basis. The amendments also require companies with a single reportable segment to provide all disclosures required by this amendment and all existing segment disclosures in ASC 280, Segment Reporting. The amendments are effective for fiscal years beginning after December 15, 2023, and interim periods beginning after December 15, 2024. The Company adopted ASU 2023-07 , effective December 31, 2024 , in these consolidated financial statements. ASU 2023-07 only impacted the disclosures and did not impact the consolidated financial statements. See Note 15, Segment Information , for disclosures related to the adoption of ASU 2023-07. Recently Issued Accounting Pronouncements In December 2023, FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures (“ASU 2023-09”). ASU 2023-09 modifies the rules on income tax disclosures to enhance the transparency and decision-usefulness of income tax disclosures, particularly in the rate reconciliation table and disclosures about income taxes paid. The amendments are intended to address investors’ requests for income tax disclosures that provide more information to help them better understand an entity’s exposure to potential changes in tax laws and the ensuing risks and opportunities and to assess income tax information that affects cash flow forecasts and capital allocation decisions. The guidance also eliminates certain existing disclosure requirements related to uncertain tax positions and unrecognized deferred tax liabilities. The guidance is effective for all entities for annual periods beginning after December 15, 2025. All entities should apply the guidance prospectively but have the option to apply it retrospectively. Early adoption is permitted. The Company is continuing to assess the timing of adoption and the potential impacts of ASU 2023-09 on the consolidated financial statements and related disclosures. In November 2024, the FASB issued ASU 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40) (“ASU 2024-03”). ASU 2024-03 modifies the rules on income statement disclosures to enhance the transparency of and include more detailed information about the types of expenses, including purchases of inventory, employee compensation, depreciation, amortization, and depletion, in commonly presented expense captions such as cost of sales, research and development, and selling, general and administrative expenses. The amendments are intended to address investors’ requests for income statement expense disclosures that provide more information to help them better understand the components of an entity’s expenses, make their own judgments about the entity’s performance, and more accurately forecast expenses, and enable investors to better assess an entity’s prospects for future cash flows. It will also provide contextual information for an entity’s presentation and consideration of management’s discussion and analysis of financial position and results of operations. The guidance is effective for all entities for annual periods beginning after December 15, 2026. All entities should apply the guidance prospectively but have the option to apply it retrospectively. Early adoption is permitted. The Company is continuing to assess the timing of adoption and the potential impacts of ASU 2024-03 on the consolidated financial statements and related disclosures.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 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 December 31, 2024 and 2023: December 31, 2024 Total Quoted Significant Significant (in thousands) Cash equivalents: Money market funds $ 73,845 $ 73,845 $ — $ — U.S. government securities 5,397 — 5,397 — U.S. commercial paper 997 — 997 — Total cash equivalents 80,239 73,845 6,394 — Marketable securities: U.S. government securities 36,457 — 36,457 — U.S. corporate bonds 269,013 — 269,013 — International corporate bonds 52,461 — 52,461 — U.S. commercial paper 30,373 — 30,373 — International commercial paper 24,144 — 24,144 — U.S. certificates of deposit 900 — 900 — U.S. municipal securities 10,049 — 10,049 — Total marketable securities 423,397 — 423,397 — $ 503,636 $ 73,845 $ 429,791 $ — December 31, 2023 Total Quoted Significant Significant (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 $ —

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 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 December 31, 2024 and 2023: December 31, 2024 Amortized Gross Unrealized Gross Unrealized Credit Losses Fair Value (in thousands) Assets: U.S. government securities $ 36,444 $ 18 $ ( 5 ) $ — $ 36,457 U.S. corporate bonds 268,841 305 ( 133 ) — 269,013 International corporate bonds 52,411 65 ( 15 ) — 52,461 U.S. commercial paper 30,373 — — — 30,373 International commercial paper 24,144 — — — 24,144 U.S. certificates of deposit 900 — — — 900 U.S. municipal securities 10,040 9 — — 10,049 $ 423,153 $ 397 $ ( 153 ) $ — $ 423,397 December 31, 2023 Amortized Gross Unrealized Gross Unrealized 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 December 31, 2024 and 2023: December 31, 2024 Less than 12 months Greater than 12 months Total Fair Unrealized Fair Unrealized Fair Unrealized (in thousands) U.S. government securities $ 11,032 $ ( 5 ) $ — $ — $ 11,032 $ ( 5 ) U.S. corporate bonds 83,946 ( 129 ) 10,197 ( 4 ) 94,143 ( 133 ) International corporate bonds 7,312 ( 15 ) — — 7,312 ( 15 ) $ 102,290 $ ( 149 ) $ 10,197 $ ( 4 ) $ 112,487 $ ( 153 ) December 31, 2023 Less than 12 months Greater than 12 months Total Fair Unrealized Fair Unrealized Fair Unrealized (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 )

Balance Sheet Components (Table

Balance Sheet Components (Tables)	12 Months Ended
	Dec. 31, 2024
Balance Sheet Related Disclosures [Abstract]
Summary of Property and Equipment, Net	The following table summarizes property and equipment, net, as of December 31, 2024 and 2023: December 31, 2024 2023 (in thousands) Computer hardware and software $ 852 $ 2,114 Furniture and equipment 822 1,786 Leasehold improvements — 5,509 1,674 9,409 Less: Accumulated depreciation ( 784 ) ( 7,488 ) $ 890 $ 1,921
Summary of Accrued Expenses	The following table summarizes accrued expenses as of December 31, 2024 and 2023: December 31, December 31, 2024 2023 (in thousands) Accrued research and development costs $ 19,758 $ 26,040 Restructuring 15,307 10,589 Employee-related 14,840 21,339 Professional services 7,114 8,589 Other 579 707 $ 57,598 $ 67,264

Leases, Commitments and Conti_2

Leases, Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Schedule of Amount of Operating Leases	The following table shows the amounts of operating leases in the balance sheets as of December 31, 2024 and 2023: December 31, Balance sheet location Balance sheet caption 2024 2023 (in thousands) Assets Right-of-use operating asset Right-of-use operating asset $ 10,753 $ 4,458 Liabilities Current operating lease Operating lease liability, current portion 1,318 5,165 Long-term operating lease Operating lease liability, net of current portion 10,518 — $ 11,836 $ 5,165
Schedule of Lease Expense by Lease Type Recognized	The following table shows the amounts of lease expense by lease type that was recognized during the years ended December 31, 2024, 2023, and 2022: Year Ended December 31, 2024 2023 2022 (in thousands) Operating lease cost $ 5,972 $ 6,748 $ 6,748 Variable lease cost 1,454 1,957 1,846 Short-term lease cost 20 20 206 Sublease income — ( 434 ) ( 421 ) $ 7,446 $ 8,291 $ 8,379
Schedule of Minimum Lease Payments	The minimum lease payments are expected to be as follows: Years Ending December 31, (In thousands) 2025 $ 2,461 2026 2,976 2027 3,059 2028 3,144 2029 3,232 Thereafter 542 Total lease payments 15,414 Less imputed interest ( 3,578 ) Present value of operating lease liabilities $ 11,836
Schedule of Weighted Average Remaining Lease Term and Weighted Average Discount Rate of Our Operating Leases	The following table shows the weighted average remaining lease term and weighted average discount rate of the operating leases: Year ended December 31, 2024 2023 Weighted average remaining lease term in years 5.17 0.69 Weighted average discount rate 10.0 % 7.5 %
Schedule of Supplemental Disclosure of Cash Flow Information Related to Operating Leases	The following table shows the supplemental disclosure of cash flow information related to the operating leases included in cash flows used by operating activities in the consolidated statements of cash flows: Year Ended December 31, 2024 2023 2022 (in thousands) Cash paid for amounts included in the $ 3,958 $ 7,643 $ 7,468 Right-of-use assets obtained in exchange $ 11,597 $ — $ —

Collaboration Agreements (Table

Collaboration Agreements (Tables)	12 Months Ended
	Dec. 31, 2024
Collaboration Agreement [Abstract]
Summary of Activity and Reimbursement Amounts Related to Collaboration Agreement	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 costs during the periods related to the development of SAGE-217 products and SAGE-324 products, as reflected in our consolidated statements of operations and comprehensive loss: Year Ended December 31, 2024 2023 2022 (in thousands) Collaboration revenue - related party $ 36,087 $ 824 $ — Cost of revenues 5,428 504 — Research and development expenses 20,617 94,325 86,028 Selling, general and administrative expenses 58,950 89,599 51,870 The revenue, cost and expense categories in the table above reflects the following reimbursement amounts to (from) Biogen to account for the sharing of economics under the Biogen Collaboration Agreement: Year Ended December 31, 2024 2023 2022 (in thousands) Collaboration revenue - related party $ ( 36,087 ) $ ( 824 ) $ — Cost of revenues ( 2,723 ) 504 — Research and development expenses ( 15,680 ) ( 76,208 ) ( 73,227 ) Selling, general and administrative expenses 10,881 16,496 ( 2,230 )

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 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 1,338,925 $ 22.76 Vested ( 430,704 ) $ 26.32 Forfeited ( 996,225 ) $ 34.99 Outstanding as of December 31, 2024 3,000,390 $ 30.04
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 Weighted Average Aggregate Outstanding as of December 31, 2023 8,118,041 $ 76.02 5.66 $ 475 Granted 2,275,745 $ 21.08 Exercised ( 10,062 ) $ 7.69 Forfeited ( 4,563,788 ) $ 79.14 Expired ( 62,112 ) $ 24.09 Outstanding as of December 31, 2024 5,757,824 $ 52.52 5.34 $ — Vested and expected to vest as of December 31, 2024 5,129,145 $ 50.56 5.17 $ — Exercisable as of December 31, 2024 4,014,487 $ 58.04 4.42 $ —
Summary of Stock-Based Compensation Expense Recognized	The following table summarizes stock-based compensation expense recognized during the years ended December 31, 2024, 2023, and 2022: Year Ended December 31, 2024 2023 2022 (in thousands) Research and development $ 18,885 $ 24,813 $ 25,888 Selling, general and administrative 35,587 47,716 35,714 Restructuring 32 838 — $ 54,504 $ 73,367 $ 61,602
Summary of Stock-Based Compensation Expense by Award Type	The following table summarizes stock-based compensation expense by award type recognized during the years ended December 31, 2024, 2023, and 2022: Year Ended December 31, 2024 2023 2022 (in thousands) Stock options $ 26,609 $ 47,695 $ 54,971 Restricted stock units 27,058 24,424 5,587 Employee stock purchase plan 837 1,248 1,044 $ 54,504 $ 73,367 $ 61,602
Summary of Weighted Average Assumptions Used to Compute Fair Value of Option Granted	The fair value of each stock option granted under the Company’s equity plans has been calculated on the date of grant using the following weighted average assumptions: Year Ended December 31, 2024 2023 2022 Expected dividend yield 0 % 0 % 0 % Expected volatility 76 % 72 % 73 % Risk-free interest rate 4.24 % 3.85 % 2.49 % Expected term 6.01 years 6.01 years 6.03 years

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	12 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
Summary of Basic and Diluted Net Income (Loss) Per Share	The following table shows the calculation of basic and diluted net loss per share for the years ended December 31, 2024, 2023, and 2022: Year Ended December 31, 2024 2023 2022 Basic net loss per share: Numerator: Net loss (in thousands) $ ( 400,666 ) $ ( 541,489 ) $ ( 532,784 ) Denominator: Weighted average common stock outstanding 60,765,913 59,836,441 59,306,094 Net loss per share - basic and diluted $ ( 6.59 ) $ ( 9.05 ) $ ( 8.98 )
Summary of Potential Dilutive Securities Outstanding	The following table summarizes potential dilutive securities outstanding at the end of each reporting period that were excluded from the calculation of diluted net loss per share because including them would have been anti-dilutive as of December 31, 2024, 2023, and 2022: Year Ended December 31, 2024 2023 2022 Stock options 5,302,824 7,663,041 7,138,350 Restricted stock units 1,788,137 1,662,363 160,403 Employee stock purchase plan 52,436 61,402 76,105 7,143,397 9,386,806 7,374,858

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2024
Income Tax Disclosure [Abstract]
Summary of Income (Loss) Before Income Tax Expense	Loss before income tax expense consists of the following: Year Ended December 31, 2024 2023 2022 (in thousands) Domestic $ ( 401,549 ) $ ( 541,656 ) $ ( 532,539 ) Foreign 883 167 ( 245 ) $ ( 400,666 ) $ ( 541,489 ) $ ( 532,784 )
Summary of Reconciliation of U.S. Statutory Rate to Company's Effective Tax Rate	A reconciliation of the U.S. statutory rate to the Company’s effective tax rate is as follows: Year Ended December 31, 2024 2023 2022 Tax due at statutory rate 21.0 % 21.0 % 21.0 % State taxes, net of federal 1.9 4.1 1.8 Stock-based compensation ( 10.2 ) ( 1.7 ) ( 1.9 ) Federal and state tax credits 2.9 2.4 2.1 Change in valuation allowance ( 15.4 ) ( 26.2 ) ( 23.0 ) Other ( 0.2 ) 0.4 — 0.0 % 0.0 % 0.0 %
Summary of Significant Components of Company's Net Deferred Tax Asset	Significant components of the Company’s net deferred tax assets at December 31, 2024 and 2023 are as follows: December 31, 2024 2023 (in thousands) Net operating losses $ 490,891 $ 428,785 Tax credits 145,113 133,602 Capitalized research and development expenses 128,001 110,690 Stock-based compensation 23,967 53,860 Accrued expenses 5,491 7,018 Depreciation and amortization 1,914 1,456 Lease liability 2,748 1,207 Right of use asset ( 2,497 ) ( 1,042 ) Other 1,090 ( 382 ) Total net deferred tax asset before valuation 796,718 735,194 Valuation allowance ( 796,718 ) ( 735,194 ) $ — $ —
Summary of Gross Unrecognized Tax Benefits Excluding Interest and Penalties	The following table reconciles the beginning and ending amounts of gross unrecognized tax benefits, excluding interest and penalties, if any, for the years ended December 31, 2024, 2023, and 2022: 2024 2023 2022 (in thousands) Balance as of January 1 $ 7,743 $ 6,846 $ 6,084 Increases related to current year tax positions 520 655 697 Increases related to prior year tax positions 15 242 65 Balance as of December 31 $ 8,278 $ 7,743 $ 6,846

Restructuring (Tables)

Restructuring (Tables)	12 Months Ended
	Dec. 31, 2024
Restructuring and Related Activities [Abstract]
Summary of Restructuring Activity	The following table summarizes activity related to the restructuring accrual inclusive of both the 2023 and 2024 Restructuring: Year Ended December 31, 2024 2023 (in thousands) Balance as of January 1 $ 10,589 $ — Restructuring expenses incurred, net 21,854 33,386 Cash paid ( 16,939 ) ( 19,163 ) Non-cash activity ( 197 ) ( 3,634 ) Balance as of December 31 $ 15,307 $ 10,589

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2024
Segment Reporting [Abstract]
Schedule of Reconciliation to the Consolidated Net Loss	A reconciliation to the consolidated net loss for the years ended December 31, 2024, 2023 and 2022 is included at the bottom of the table below. Year Ended December 31, 2024 2023 2022 (in thousands) Revenues $ 41,243 $ 86,455 $ 7,686 Cost of revenues 9,444 2,159 813 Program expenses (1) ZULRESSO 5,101 4,395 17,083 zuranolone (ZURZUVAE) 30,482 94,174 68,155 SAGE-324 10,173 16,574 14,646 dalzanemdor (SAGE-718) 58,248 56,536 50,584 Other research and development programs 33,277 52,975 49,750 Non-program expenses (2) 85,405 113,388 96,825 People and staff augmentation 165,158 220,188 195,214 Restructuring 21,854 33,386 — Other segment items (3) 22,767 34,169 47,400 Net loss $ ( 400,666 ) $ ( 541,489 ) $ ( 532,784 ) (1) Includes external research and development, and selling, general and administrative expenses. (2) Includes information technology, infrastructure, facilities, legal, commercial data and systems, chemistry platform, intellectual property, and other general and administrative expense. (3) Includes stock-based compensation expense, interest income, and other (income) expense.

Nature of the Business - Additi

Nature of the Business - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended			12 Months Ended
	Oct. 31, 2024	Jan. 31, 2024	Aug. 31, 2023	Dec. 31, 2024	Dec. 31, 2020	Dec. 31, 2023
Nature Of Business [Line Items]
Incremental cost of impairment of intangible assets and excess inventory write-off				$ 5,400
Percentage of workforce eliminated			40%
Net income from up-front					$ 606,100
Accumulated deficit				2,970,325		$ 2,569,659
Research and Development Workforce [Member]
Nature Of Business [Line Items]
Percentage of workforce eliminated	55%	55%
Total Workforce [Member]
Nature Of Business [Line Items]
Percentage of workforce eliminated	33%
Redeemable Convertible Preferred Stock [Member] | Convertible Notes [Member] | Initial Public Offering [Member]
Nature Of Business [Line Items]
Accumulated deficit				$ 3,000,000

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Summary Of Significant Accounting Policies [Line Items]
Incremental costs incurred expected amortization period of asset	true
Impairment losses on long-lived assets	$ 2.2
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]	true
Change in Accounting Principle, Accounting Standards Update, Adoption Date	Dec. 31, 2024
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]	false
Accounting Standards Update [Extensible Enumeration]	Accounting Standards Update 2023-07 [Member]
Prepaid Expenses and Other Current Assets [Member]
Summary Of Significant Accounting Policies [Line Items]
Trade accounts receivables	$ 0.4	$ 1.4
Inventory	$ 0	$ 1.5

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Company's Cash Equivalents and Marketable Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	$ 80,239	$ 68,547
Total marketable securities	423,397	682,192
Total cash equivalents and marketable securities	503,636	750,739
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	73,845	59,852
Total cash equivalents and marketable securities	73,845	59,852
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	6,394	8,695
Total marketable securities	423,397	682,192
Total cash equivalents and marketable securities	429,791	690,887
Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	73,845	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	73,845	59,852
U.S. Government Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	5,397	8,695
Total marketable securities	36,457	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	5,397	8,695
Total marketable securities	36,457	166,925
U.S. Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	997
Total marketable securities	30,373	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 cash equivalents	997
Total marketable securities	30,373	23,370
U.S. Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	269,013	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 marketable securities	269,013	210,198
International Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	52,461	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 marketable securities	52,461	97,675
International Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	24,144	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	24,144	46,900
U.S. Certificates of Deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	900	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	900	8,830
U.S. Municipal Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	10,049	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	$ 10,049	$ 128,294

Fair Value Measurements - Addit

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

Investments - Summary of Gross

Investments - Summary of Gross Unrealized Gains and Losses and Credit Losses (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 423,153	$ 683,006
Gross Unrealized Gains	397	437
Gross Unrealized Losses	(153)	(1,251)
Fair Value	423,397	682,192
U.S. Government Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	36,444	167,165
Gross Unrealized Gains	18	107
Gross Unrealized Losses	(5)	(347)
Fair Value	36,457	166,925
U.S. Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	268,841	210,491
Gross Unrealized Gains	305	191
Gross Unrealized Losses	(133)	(484)
Fair Value	269,013	210,198
International Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	52,411	97,698
Gross Unrealized Gains	65	99
Gross Unrealized Losses	(15)	(122)
Fair Value	52,461	97,675
U.S. Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	30,373	23,360
Gross Unrealized Gains		11
Gross Unrealized Losses		(1)
Fair Value	30,373	23,370
International Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	24,144	46,935
Gross Unrealized Gains		3
Gross Unrealized Losses		(38)
Fair Value	24,144	46,900
U.S. Certificates of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	900	8,830
Fair Value	900	8,830
U.S. Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	10,040	128,527
Gross Unrealized Gains	9	26
Gross Unrealized Losses		(259)
Fair Value	$ 10,049	$ 128,294

Investments - Additional Inform

Investments - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2024	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	$ 30,700,000	$ 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	$ 3,400,000	$ 4,200,000

Investments - Summary of Fair V

Investments - Summary of Fair Value And Unrealized Losses of Marketable Securities In Loss Position (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-Sale [Line Items]
Less than 12 months, Fair Value	$ 102,290	$ 343,373
Less than 12 months, Unrealized Losses	(149)	(611)
Greater than 12 months, Fair Value	10,197	123,121
Greater than 12 months, Unrealized Losses	(4)	(640)
Fair Value	112,487	466,494
Unrealized Losses	(153)	(1,251)
U.S. Government Securities [Member]
Debt Securities, Available-for-Sale [Line Items]
Less than 12 months, Fair Value	11,032	52,521
Less than 12 months, Unrealized Losses	(5)	(96)
Greater than 12 months, Fair Value		41,911
Greater than 12 months, Unrealized Losses		(251)
Fair Value	11,032	94,432
Unrealized Losses	(5)	(347)
U.S. Corporate Bonds [Member]
Debt Securities, Available-for-Sale [Line Items]
Less than 12 months, Fair Value	83,946	111,901
Less than 12 months, Unrealized Losses	(129)	(246)
Greater than 12 months, Fair Value	10,197	43,851
Greater than 12 months, Unrealized Losses	(4)	(238)
Fair Value	94,143	155,752
Unrealized Losses	(133)	(484)
International Corporate Bonds [Member]
Debt Securities, Available-for-Sale [Line Items]
Less than 12 months, Fair Value	7,312	43,708
Less than 12 months, Unrealized Losses	(15)	(87)
Greater than 12 months, Fair Value		6,014
Greater than 12 months, Unrealized Losses		(35)
Fair Value	7,312	49,722
Unrealized Losses	$ (15)	(122)
U.S. Commercial Paper [Member]
Debt Securities, Available-for-Sale [Line Items]
Less than 12 months, Fair Value		7,848
Less than 12 months, Unrealized Losses		(1)
Fair Value		7,848
Unrealized Losses		(1)
International Commercial Paper [Member]
Debt Securities, Available-for-Sale [Line Items]
Less than 12 months, Fair Value		37,300
Less than 12 months, Unrealized Losses		(38)
Fair Value		37,300
Unrealized Losses		(38)
U.S. Municipal Securities [Member]
Debt Securities, Available-for-Sale [Line Items]
Less than 12 months, Fair Value		90,095
Less than 12 months, Unrealized Losses		(143)
Greater than 12 months, Fair Value		31,345
Greater than 12 months, Unrealized Losses		(116)
Fair Value		121,440
Unrealized Losses		$ (259)

Balance Sheet Components - Summ

Balance Sheet Components - Summary of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 1,674	$ 9,409
Less: Accumulated depreciation	(784)	(7,488)
Property and equipment, net	890	1,921
Computer Hardware and Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	852	2,114
Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	822	1,786
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 0	$ 5,509

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 1,031	$ 1,393	$ 1,122
Purchase commitment, cancelling excess amount committed	400	4,300
Research and Development Expense [Member]
Property, Plant and Equipment [Line Items]
Purchase commitment, cancelling excess amount committed		$ 28,900
Research and Development Expense [Member] | Biogen Collaboration Agreement [Member]
Property, Plant and Equipment [Line Items]
Reimbursement expense	$ 14,500
Computer Hardware and Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	3 years
Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	5 years

Balance Sheet Components - Su_2

Balance Sheet Components - Summary of Accrued Expenses (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Payables and Accruals [Abstract]
Accrued research and development costs	$ 19,758	$ 26,040
Restructuring	15,307	10,589
Employee-related	14,840	21,339
Professional services	7,114	8,589
Other	579	707
Total accrued expenses	$ 57,598	$ 67,264

Leases, Commitments and Conti_3

Leases, Commitments and Contingencies - Operating Leases - Additional Information (Detail) $ in Thousands	1 Months Ended	12 Months Ended
	Jan. 31, 2024 USD ($)	Dec. 31, 2024 USD ($) ft²	Dec. 31, 2023 USD ($) ft²	Dec. 31, 2022 ft²	Aug. 02, 2024 USD ($)
Commitments And Contingencies [Line Items]
Operating lease option to extend		true
Operating lease renewal term		5 years
Operating lease, right-of-use asset		$ 10,753	$ 4,458
Operating lease, liability		$ 11,836	$ 5,165
Lease Agreements [Member]
Commitments And Contingencies [Line Items]
Lease expire date	Feb. 28, 2030
Operating lease option to extend		The Company has the option to extend the New Lease one time for an additional five-year period,
Operating lease renewal term	5 years
Operating lease, right-of-use asset					$ 11,600
Operating lease, liability					10,000
Reclassification from prepaid expenses and other current assets to right-of-use asset related to build out costs					$ 1,500
Lease Commencement Date	Sep. 01, 2024
Initial term	66 months
Lease Agreements [Member] | Letter of Credit [Member]
Commitments And Contingencies [Line Items]
Security Deposit	$ 1,400
Security deposit amount reduced for third anniversary	$ 1,200
Operating Lease One [Member]
Commitments And Contingencies [Line Items]
Office space rent under operating lease | ft²		63,017	63,017	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	40,419	40,419
Lease expire date		Aug. 31, 2024	Aug. 31, 2024	Aug. 31, 2024
Operating Lease Three [Member]
Commitments And Contingencies [Line Items]
Office space rent under operating lease | ft²		15,525	15,525	15,525
Lease expire date		Nov. 30, 2024	Nov. 30, 2024	Nov. 30, 2024
Operating Lease Five [Member]
Commitments And Contingencies [Line Items]
Office space rent under operating lease | ft²		30,567	30,567	30,567
Lease expire date		Feb. 28, 2030	Feb. 28, 2030	Feb. 28, 2030
Minimum [Member]
Commitments And Contingencies [Line Items]
Operating lease remaining lease terms		1 year
Maximum [Member]
Commitments And Contingencies [Line Items]
Operating lease remaining lease terms		5 years

Leases, Commitments and Conti_4

Leases, Commitments and Contingencies - Schedule of Amounts of Operating Leases (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Assets
Right-of-use operating asset	$ 10,753	$ 4,458
Liabilities
Current operating lease liabilities	1,318	5,165
Long-term operating lease liabilities	10,518	0
Total operating lease liabilities	$ 11,836	$ 5,165

Leases, Commitments and Conti_5

Leases, Commitments and Contingencies - Schedule of Lease Expense by Lease Type Recognized (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Operating lease cost	$ 5,972	$ 6,748	$ 6,748
Variable lease cost	1,454	1,957	1,846
Short-term lease cost	20	20	206
Sublease income	0	(434)	(421)
Total	$ 7,446	$ 8,291	$ 8,379

Leases, Commitments and Conti_6

Leases, Commitments and Contingencies - Schedule of Minimum Lease Payments (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Lessee, Operating Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract]
2025	$ 2,461
2026	2,976
2027	3,059
2028	3,144
2029	3,232
Thereafter	542
Total lease payments	15,414
Less imputed interest	(3,578)
Present value of operating lease liabilities	$ 11,836	$ 5,165

Leases, Commitments and Conti_7

Leases, Commitments and Contingencies - Schedule of Weighted Average Remaining Lease Term and Weighted Average Discount Rate of Our Operating Leases (Detail)	Dec. 31, 2024	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Weighted average remaining lease term in years	5 years 2 months 1 day	8 months 8 days
Weighted average discount rate	10%	7.50%

Leases, Commitments and Conti_8

Leases, Commitments and Contingencies - Schedule of Supplemental Disclosure of Cash Flow Information Related To Operating Leases (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Cash paid for amounts included in the measurement of lease liabilities	$ 3,958	$ 7,643	$ 7,468
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 11,597	$ 0	$ 0

Collaboration Agreements - Addi

Collaboration Agreements - Additional Information (Detail) - USD ($)

1 Months Ended

3 Months Ended

9 Months Ended

12 Months Ended

Nov. 30, 2020

Jun. 30, 2018

Jan. 31, 2024

Dec. 31, 2023

Dec. 31, 2022

Dec. 31, 2021

Jun. 30, 2018

Sep. 30, 2024

Sep. 30, 2023

Sep. 30, 2022

Dec. 31, 2024

Dec. 31, 2023

Dec. 31, 2022

Dec. 31, 2020

Jun. 12, 2018

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Revenue

$ 41,243,000

$ 86,455,000

$ 7,686,000

Collaboration receivable - related party

$ 83,009,000

9,134,000

83,009,000

Other Collaboration Revenue [Member]

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Revenue

1,582,000

177,000

Shionogi Collaboration Agreement [Member] | Collaboration Revenue [Member]

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Revenue

600,000

200,000

0

Shionogi Collaboration Agreement [Member] | SAGE-217 [Member]

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Upfront payment

$ 90,000,000

Average percentage on tiered royalties

20%

Revenue

$ 90,000,000

Standalone selling price of license performance obligation

$ 90,000,000

90,000,000

Shionogi Collaboration Agreement [Member] | SAGE-217 [Member] | Regulatory Milestones [Member]

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Future milestone payments

55,000,000

Shionogi Collaboration Agreement [Member] | SAGE-217 [Member] | Maximum [Member]

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Additional milestone payment receivable

485,000,000

$ 485,000,000

Shionogi Collaboration Agreement [Member] | SAGE-217 [Member] | Maximum [Member] | Regulatory Milestones [Member]

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Future milestone payments

70,000,000

Shionogi Collaboration Agreement [Member] | SAGE-217 [Member] | Maximum [Member] | Commercial Milestones [Member]

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Future milestone payments

30,000,000

Shionogi Collaboration Agreement [Member] | SAGE-217 [Member] | Maximum [Member] | Sales Milestones [Member]

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Future milestone payments

$ 385,000,000

Biogen Collaboration Agreement [Member]

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Collaboration agreement effective date

Dec. 28, 2020

Upfront payment

$ 875,000,000

Revenue

1,100,000,000

Sale of stock, consideration received

$ 1,500,000,000

Issuance of common stock upon public offering, net of issuance costs, Shares

6,241,473

Purchase price

$ 650,000,000

Net reimbursement

8,000,000

(36,087,000)

(824,000)

Milestone achieved

75,000,000

Payments to related parties

0

0

0

Proceeds from related parties

118,100,000

$ 65,700,000

$ 80,300,000

$ 118,100,000

$ 65,700,000

$ 80,300,000

Biogen Collaboration Agreement [Member] | Related Party [Member]

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Collaboration receivable - related party

83,000,000

9,100,000

83,000,000

Biogen Collaboration Agreement [Member] | Other Collaboration Revenue [Member]

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Revenue

900,000

$ 0

0

Biogen Collaboration Agreement [Member] | License And Milestone Revenue - Related Party [Member]

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Revenue

75,000,000

$ 0

$ 0

Milestone Payments

$ 75,000,000

Biogen Collaboration Agreement [Member] | SAGE-217 [Member] | First Commercial Sale Of Zurzuvae For Treatment Of Women With Ppd [Member]

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Future milestone payments

150,000,000

Milestone achieved

$ 75,000,000

Biogen Collaboration Agreement [Member] | SAGE-217 [Member] | Maximum [Member]

Collaborative Arrangement and Arrangement Other than Collaborative [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 Arrangement and Arrangement Other than Collaborative [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 Arrangement and Arrangement Other than Collaborative [Line Items]

Future milestone payments

75,000,000

Biogen Collaboration Agreement [Member] | SAGE-217 [Member] | Maximum [Member] | Sales Milestones [Member]

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Future milestone payments

300,000,000

Biogen Collaboration Agreement [Member] | SAGE-217 [Member] | Maximum [Member] | Regulatory and Commercial Milestones [Member]

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Future milestone payments

475,000,000

Biogen Collaboration Agreement [Member] | SAGE-324 [Member] | Maximum [Member] | Sales Milestones [Member]

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Future milestone payments

300,000,000

Biogen Collaboration Agreement [Member] | SAGE-324 [Member] | Maximum [Member] | Regulatory and Commercial Milestones [Member]

Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]

Future milestone payments

$ 520,000,000

Biogen Stock Purchase Agreement [Member]

Collaborative Arrangement and Arrangement Other than Collaborative [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

Collaboration Agreements - Summ

Collaboration Agreements - Summary of Activity and Reimbursement Amounts Related to Collaboration Agreement (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2020
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue		$ 41,243	$ 86,455	$ 7,686
Research and development expenses		225,895	356,235	326,163
Selling, general and administrative expenses		216,420	274,524	227,699
Collaboration Revenue - Related Party [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue		36,087	824
Biogen Collaboration Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue					$ 1,100,000
Cost of revenues		5,428	504
Research and development expenses		20,617	94,325	86,028
Selling, general and administrative expenses		58,950	89,599	51,870
Reimbursement amounts to (from) collaboration [Abstract]
Collaboration revenue - related party	$ 8,000	(36,087)	(824)
Cost of revenues		(2,723)	504
Selling, general and administrative expenses		10,881	16,496	(2,230)
Biogen Collaboration Agreement [Member] | Research and Development [Member]
Reimbursement amounts to (from) collaboration [Abstract]
Research and development expenses		(15,680)	(76,208)	$ (73,227)
Biogen Collaboration Agreement [Member] | Collaboration Revenue - Related Party [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue		$ 36,087	$ 824

Preferred Stock - Additional In

Preferred Stock - Additional Information (Detail) - shares	Dec. 31, 2024	Dec. 31, 2023
Temporary Equity Disclosure [Abstract]
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0

Common Stock - Additional Infor

Common Stock - Additional Information (Detail) - USD ($)		12 Months Ended
	Sep. 16, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Subsidiary or Equity Method Investee [Line Items]
Common stock, shares authorized		120,000,000	120,000,000
Common stock, par value		$ 0.0001	$ 0.0001
Dividends declared		$ 0	$ 0
Voting rights		Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders.
Purchase of treasury stock, Shares		3,033
Total cost of shares held in treasury		$ 400,000	400,000
Sale of stock, commissions, underwriting discounts, and offering costs		$ 117,000	$ 0	$ 0
Original Sales Agreement [Member]
Subsidiary or Equity Method Investee [Line Items]
Aggregate offering price of common stock shares issued	$ 250,000,000
Aggregate offering price of shares remained amount unsold	241,700,000
Number of shares issued or sold			0
Sale of stock, number of shares issued in transaction (in shares)		700,000
Price per share		$ 11.9
Gross proceeds		$ 8,300,000
Sale of stock, commissions, underwriting discounts, and offering costs		$ 300,000
ATM 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
Shares remained available for issuance		250,000,000
ATM Sales Agreement [Member] | Maximum [Member]
Subsidiary or Equity Method Investee [Line Items]
Percentage of sales commission	3%

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail)				12 Months Ended
	Jun. 10, 2024 shares	Feb. 21, 2024 $ / shares shares	Jun. 15, 2023 shares	Dec. 31, 2024 USD ($) Milestone $ / shares shares	Dec. 31, 2023 USD ($) Milestone $ / shares shares	Dec. 31, 2022 USD ($) Milestone $ / shares shares	Apr. 16, 2024 shares	Jan. 23, 2024 $ / shares	Jun. 16, 2022 shares	Sep. 20, 2018 shares	Jul. 02, 2014 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation granted under plan vested period				4 years
Share based compensation, vest period				1 year
Share based compensation, term of plan				10 years
Stock-based compensation expense | $				$ 54,504,000	$ 73,367,000	$ 61,602,000
Stock-based compensation expense tied to total stockholder return | $				$ 54,504,000	$ 73,367,000	$ 61,602,000
Weighted average grant date fair value per share | $ / shares				$ 14.23	$ 29.53	$ 25.96
Share option, weighted-average forfeiture rates				15.10%	16.60%	19.20%
Restructuring [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense | $				$ 32,000	$ 838,000	$ 0
Time Based Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units granted				938,470	1,734,717	0
Restricted stock units vested				272,844	51,851	366,014
Fair value of restricted stock units vested | $				$ 2,800,000	$ 1,800,000	$ 12,400,000
Outstanding and unvested restricted stock units				1,788,137
Total unrecognized stock-based compensation expense | $				$ 13,800,000
Weighted average period of unrecognized compensation costs				1 year 5 months 4 days
Performance Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units granted				400,455	905,012	705,380
Fair value of restricted stock units vested | $						$ 0
Stock-based compensation expense | $				$ 4,000,000	$ 0	0
Stock-based compensation expense to be recognized | $				400,000
Stock-based compensation expense tied to total stockholder return | $				$ 800,000	$ 700,000
Outstanding and unvested restricted stock units				1,212,253
Total unrecognized stock-based compensation expense | $				$ 42,900,000
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted				2,275,745
Total number of shares outstanding				5,757,824	8,118,041
Stock-based compensation expense | $				$ 26,609,000	$ 47,695,000	54,971,000
Total unrecognized stock-based compensation expense | $				$ 24,100,000
Weighted average period of unrecognized compensation costs				3 years 2 months 4 days
Intrinsic value of options exercised | $				$ 100,000	$ 1,900,000	4,400,000
Stock options exercise price per share | $ / shares				$ 52.52	$ 76.02
Exercise price per share of the replacement options | $ / shares				$ 58.04
Performance-Based Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense | $				$ 0	$ 0	$ 0
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted				0	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				1,338,925
Stock-based compensation expense | $				$ 27,058,000	$ 24,424,000	$ 5,587,000
Outstanding and unvested restricted stock units				3,000,390	3,088,394
Performance restricted stock units vested				430,704
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%
2011 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted				0
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 | $				$ 1,400,000	$ 9,600,000
Stock-based compensation expense | $				$ 3,600,000	$ 14,300,000
Regulatory development Milestone achieved | Milestone					3
2014 Plan [Member] | Performance-Based Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense | $					$ 10,700,000
Regulatory development Milestone achieved | Milestone				0	1	0
2016 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total number of shares reserved for issuance							428,074			1,200,000
2014 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total number of shares reserved for issuance			1,082,000						300,000		282,000
Additional number of shares reserved for issuance			500,000
Common stock available for issuance under stock option plan				419,194
Number of shares issued under the plan				662,806
2024 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares annual increase added to plan	11,002,166
Total number of shares reserved for issuance	5,500,000
Common stock available for issuance under stock option plan				7,490,967
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
Options to purchase		3,079,608
Exercise price per share of the replacement options | $ / shares		$ 22.2
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
2024 Plan, 2014 Plan and 2016 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total number of shares outstanding				8,758,214

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Activity Relating to Restricted Stock Units (Detail) - Restricted Stock Units [Member]	12 Months Ended
	Dec. 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	1,338,925
Vested, Shares | shares	(430,704)
Forfeited, Shares | shares	(996,225)
Outstanding, Shares at ending balance | shares	3,000,390
Outstanding, Weighted Average Grant Date Fair Value at beginning balance | $ / shares	$ 34.27
Granted, Weighted Average Grant Date Fair Value | $ / shares	22.76
Vested, Weighted Average Grant Date Fair Value | $ / shares	26.32
Forfeited, Weighted Average Grant Date Fair Value | $ / shares	34.99
Outstanding, Weighted Average Grant Date Fair Value at ending balance | $ / shares	$ 30.04

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Activity Relating to Time Based and Performance Based Stock Options (Detail) - Stock Options [Member] - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, Outstanding Shares	8,118,041
Granted, Shares	2,275,745
Exercised, Shares	(10,062)
Forfeited, Shares	(4,563,788)
Expired, Shares	(62,112)
Ending balance, Outstanding Shares	5,757,824	8,118,041
Vested and expected to vest, Shares	5,129,145
Exercisable, Shares	4,014,487
Beginning balance, Outstanding Weighted Average Exercise Price	$ 76.02
Granted, Weighted Average Exercise Price	21.08
Exercised, Weighted Average Exercise Price	7.69
Forfeited, Weighted Average Exercise Price	79.14
Expired, Weighted Average Exercise Price	24.09
Ending balance, Outstanding Weighted Average Exercise Price	52.52	$ 76.02
Vested and expected to vest, Weighted Average Exercise Price	50.56
Exercisable, Weighted Average Exercise Price	$ 58.04
Outstanding, Weighted Average Remaining Life	5 years 4 months 2 days	5 years 7 months 28 days
Vested and expected to vest, Weighted Average Remaining Life	5 years 2 months 1 day
Exercisable, Weighted Average Remaining Life	4 years 5 months 1 day
Outstanding, Aggregate Intrinsic Value		$ 475

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of Stock-Based Compensation Expense Recognized (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	$ 54,504	$ 73,367	$ 61,602
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	18,885	24,813	25,888
Selling, General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	35,587	47,716	35,714
Restructuring [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	$ 32	$ 838	$ 0

Stock-Based Compensation - Su_4

Stock-Based Compensation - Summary of Stock-Based Compensation Expense by Award Type (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	$ 54,504	$ 73,367	$ 61,602
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	26,609	47,695	54,971
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	27,058	24,424	5,587
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	$ 837	$ 1,248	$ 1,044

Stock-Based Compensation - Su_5

Stock-Based Compensation - Summary of Weighted Average Assumptions Used to Compute Fair Value of Option Granted (Detail)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Expected dividend yield	0%	0%	0%
Expected volatility	76%	72%	73%
Risk-free interest rate	4.24%	3.85%	2.49%
Expected term	6 years 3 days	6 years 3 days	6 years 10 days

Net Loss Per Share - Summary of

Net Loss Per Share - Summary of Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Numerator:
Net Income (Loss)	$ (400,666)	$ (541,489)	$ (532,784)
Denominator:
Weighted average common stock outstanding - basic	60,765,913	59,836,441	59,306,094
Weighted average common stock outstanding - diluted	60,765,913	59,836,441	59,306,094
Net loss per share - basic	$ (6.59)	$ (9.05)	$ (8.98)
Net loss per share - diluted	$ (6.59)	$ (9.05)	$ (8.98)

Net Loss Per Share - Summary _2

Net Loss Per Share - Summary of Potential Dilutive Securities Outstanding (Detail) - shares	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents	7,143,397	9,386,806	7,374,858
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents	5,302,824	7,663,041	7,138,350
Restricted Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents	1,788,137	1,662,363	160,403
Employee Stock Purchase Plan [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents	52,436	61,402	76,105

Income Taxes - Summary of Incom

Income Taxes - Summary of Income (Loss) Before Income Tax Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Domestic	$ (401,549)	$ (541,656)	$ (532,539)
Foreign	883	167	(245)
Net income (loss) before income tax expense	$ (400,666)	$ (541,489)	$ (532,784)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)		12 Months Ended
	Aug. 16, 2022	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Line Items]
Current tax expense		$ 0
Research and development expense		225,895,000	$ 356,235,000	$ 326,163,000
Deferred tax expense		0
Inflation reduction of corporate alternative minimum tax	15%
Inflation reduction of excise tax on stock repurchases	1%
Federal operating loss carryforwards		$ 2,000,000,000
Federal net operating loss carryforwards, limitation percentage		80%
Federal orphan drug tax credit carry forwards		$ 40,100,000
Tax credit carry forwards expiration period		2034
Change in amount of deferred tax assets		$ 61,500,000
Valuation allowance		796,718,000	735,194,000
Valuation allowance, increase (decrease), amount		61,500,000	141,900,000	122,700,000
Accrued interest or penalties related to uncertain tax positions		0	0
Uncertain tax positions		0	$ 0	$ 0
Begin to Expire 2033 [Member]
Income Tax Disclosure [Line Items]
Federal operating loss carryforwards		$ 30,400,000
Federal net operating loss carryforwards expiration year		2033
State operating loss carryforwards		$ 1,100,000,000
State net operating loss carryforwards expiration year		2033
Domestic Tax Authority [Member]
Income Tax Disclosure [Line Items]
Research and development tax credits carryforwards		$ 90,500,000
Research and development tax credits carryforwards expiration year		2031
State and Local Jurisdiction [Member]
Income Tax Disclosure [Line Items]
Research and development tax credits carryforwards		$ 18,400,000
Research and development tax credits carryforwards expiration year		2032

Income Taxes - Summary of Recon

Income Taxes - Summary of Reconciliation of U.S. Statutory Rate to Company's Effective Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Tax due at statutory rate	21%	21%	21%
State taxes, net of federal	1.90%	4.10%	1.80%
Stock-based compensation	(10.20%)	(1.70%)	(1.90%)
Federal and state tax credits	2.90%	2.40%	2.10%
Change in valuation allowance	(15.40%)	(26.20%)	(23.00%)
Other	(0.20%)	0.40%
Total effective tax rate	0%	0%	0%

Income Taxes - Summary of Signi

Income Taxes - Summary of Significant Components of Company's Net Deferred Tax Asset (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Net operating losses	$ 490,891	$ 428,785
Tax credits	145,113	133,602
Capitalized research and development expenses	128,001	110,690
Stock-based compensation	23,967	53,860
Accrued expenses	5,491	7,018
Depreciation and amortization	1,914	1,456
Lease liability	2,748	1,207
Right of use asset	(2,497)	(1,042)
Other	1,090	(382)
Total net deferred tax asset before valuation allowance	796,718	735,194
Valuation allowance	$ (796,718)	$ (735,194)

Income Taxes - Summary of Gross

Income Taxes - Summary of Gross Unrecognized Tax Benefits Excluding Interest and Penalties (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Balance as of January 1	$ 7,743	$ 6,846	$ 6,084
Increases related to current year tax positions	520	655	697
Increases related to prior year tax positions	15	242	65
Balance as of December 31	$ 8,278	$ 7,743	$ 6,846

Employee Benefit Plan - Additio

Employee Benefit Plan - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Postemployment Benefits [Abstract]
Employer matching contribution, percent of match	50%	50%	50%
Maximum annual contributions per employee, percent	6%	6%	6%
Employer contribution	$ 2.9	$ 3.9	$ 3
Defined Contribution Plan, Sponsor Location [Extensible Enumeration]	us-gaap:DomesticPlanMember	us-gaap:DomesticPlanMember	us-gaap:DomesticPlanMember
Defined Contribution Plan, Tax Status [Extensible Enumeration]	us-gaap:QualifiedPlanMember	us-gaap:QualifiedPlanMember	us-gaap:QualifiedPlanMember

Restructuring - Schedule of Res

Restructuring - Schedule of Restructuring Activity (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Restructuring Reserve [Roll Forward]
Restructuring accrual, Balance as of January 1	$ 10,589	$ 0
Restructuring expenses incurred, net	21,854	33,386
Cash paid	(16,939)	(19,163)
Non-cash activity	(197)	(3,634)
Restructuring accrual, Balance as of December 31	$ 15,307	$ 10,589

Restructuring - Additional Info

Restructuring - Additional Information (Detail) - USD ($) $ in Millions		1 Months Ended			12 Months Ended
	Jun. 30, 2025	Oct. 31, 2024	Jan. 31, 2024	Aug. 31, 2023	Dec. 31, 2024	Dec. 31, 2023
Restructuring Cost and Reserve [Line Items]
Percentage of workforce eliminated				40%
Restructuring expense					$ 22.3	$ 33.4
Reversal of restructuring expense					0.5
Restructuring charges expected to be incurred					$ 32.9
Total Workforce [Member]
Restructuring Cost and Reserve [Line Items]
Percentage of workforce eliminated		33%
Research and Development Workforce [Member]
Restructuring Cost and Reserve [Line Items]
Percentage of workforce eliminated		55%	55%
Forecast [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	$ 1.3
Restructuring charges expected to be incurred	$ 23.6

Segment Information - Schedule

Segment Information - Schedule of Reconciliation to the Consolidated Net Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Revenues	$ 41,243	$ 86,455	$ 7,686
Cost of revenues	9,444	2,159	813
Non-program Expenses	85,405	113,388	96,825
Restructuring	21,854	33,386
Net loss	(400,666)	(541,489)	(532,784)
Corporate and Reconciling Items [Member]
Segment Reporting Information [Line Items]
Revenues	41,243	86,455	7,686
Cost of revenues	9,444	2,159	813
People and staff augmentation	165,158	220,188	195,214
Restructuring	21,854	33,386
Other segment items	22,767	34,169	47,400
Net loss	(400,666)	(541,489)	(532,784)
Corporate and Reconciling Items [Member] | ZULRESSO [Member]
Segment Reporting Information [Line Items]
Total program expenses	5,101	4,395	17,083
Corporate and Reconciling Items [Member] | zuranolone (ZURZUVAE) [Member]
Segment Reporting Information [Line Items]
Total program expenses	30,482	94,174	68,155
Corporate and Reconciling Items [Member] | SAGE-324 [Member]
Segment Reporting Information [Line Items]
Total program expenses	10,173	16,574	14,646
Corporate and Reconciling Items [Member] | dalzanemdor (SAGE-718) [Member]
Segment Reporting Information [Line Items]
Total program expenses	58,248	56,536	50,584
Corporate and Reconciling Items [Member] | Other research and development programs [Member]
Segment Reporting Information [Line Items]
Total program expenses	$ 33,277	$ 52,975	$ 49,750

Segment Information - Additiona

Segment Information - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2024 Segment
Segment Reporting [Abstract]
Number of reportable segment	1
Segment Reporting, CODM, Individual Title and Position or Group Name [Extensible Enumeration]	Chief Executive Officer [Member]
Segment Reporting, CODM, Profit (Loss) Measure, How Used, Description	The CODM manages and allocates resources to the operations of the Company on a total company basis. Managing and allocating resources on a consolidated basis enables the CEO to assess the overall level of resources available and how to best deploy these resources across functions, therapeutic areas and research and development projects that are in line with the Company’s long-term company-wide strategic goals.

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail)	Jan. 10, 2025 $ / shares
Subsequent Event [Member] | Biogen Inc. [Member]
Subsequent Event [Line Items]
Acquisition outstanding share per share Price	$ 7.22