Sage Therapeutics (SAGE) 10-Q 31 Jul 24 2024 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2024	Jul. 24, 2024
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q2
Trading Symbol	SAGE
Entity Registrant Name	Sage Therapeutics, Inc.
Entity Central Index Key	0001597553
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Common Stock, Shares Outstanding		61,050,418
Entity Shell Company	false
Entity File Number	001-36544
Entity Tax Identification Number	27-4486580
Entity Address, Address Line One	215 First Street
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02142
City Area Code	617
Local Phone Number	299-8380
Entity Interactive Data Current	Yes
Entity Incorporation, State or Country Code	DE
Document Quarterly Report	true
Document Transition Report	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 99,901	$ 70,992
Marketable securities	546,892	682,192
Prepaid expenses and other current assets	28,743	31,825
Collaboration receivable - related party	9,943	83,009
Restricted cash	$ 1,332	$ 1,332
Accounts Receivable, after Allowance for Credit Loss, Current, Related Party [Extensible Enumeration]	Related Party [Member]	Related Party [Member]
Total current assets	$ 686,811	$ 869,350
Property and equipment, net	1,274	1,921
Right-of-use operating asset	1,220	4,458
Other long-term assets	7,800	6,548
Total assets	697,105	882,277
Current liabilities:
Accounts payable	8,650	10,318
Accrued expenses	58,982	67,264
Operating lease liability, current portion	1,411	5,165
Total current liabilities	69,043	82,747
Total liabilities	69,043	82,747
Commitments and contingencies (Note 6)
Stockholders’ equity:
Preferred stock, $0.0001 par value per share; 5,000,000 shares authorized at June 30, 2024 and December 31, 2023; no shares issued or outstanding at June 30, 2024 and December 31, 2023
Common stock, $0.0001 par value per share; 120,000,000 shares authorized at June 30, 2024 and December 31, 2023; 60,897,967 and 60,046,676 shares issued at June 30, 2024 and December 31, 2023; 60,894,934 and 60,043,643 shares outstanding at June 30, 2024 and December 31, 2023	6	6
Treasury stock, at cost, 3,033 shares at June 30, 2024 and December 31, 2023	(400)	(400)
Additional paid-in capital	3,410,143	3,370,397
Accumulated deficit	(2,780,996)	(2,569,659)
Accumulated other comprehensive loss	(691)	(814)
Total stockholders’ equity	628,062	799,530
Total liabilities and stockholders’ equity	$ 697,105	$ 882,277

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares issued	60,897,967	60,046,676
Common stock, shares outstanding	60,894,934	60,043,643
Treasury stock, shares	3,033	3,033

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Total revenue	$ 8,654	$ 2,474	$ 16,556	$ 5,768
Operating costs and expenses:
Cost of revenues	1,407	205	2,676	435
Research and development	62,564	97,161	134,297	189,987
Selling, general and administrative	55,983	75,565	108,556	141,273
Total operating costs and expenses	119,954	172,931	245,529	331,695
Loss from operations	(111,300)	(170,457)	(228,973)	(325,927)
Interest income, net	8,431	10,173	17,634	19,003
Other income (expense), net	15	(41)	2	(229)
Net loss	$ (102,854)	$ (160,325)	$ (211,337)	$ (307,153)
Net loss per share - basic	$ (1.7)	$ (2.68)	$ (3.5)	$ (5.14)
Net loss per share - diluted	$ (1.7)	$ (2.68)	$ (3.5)	$ (5.14)
Weighted average number of common shares outstanding— basic	60,538,319	59,769,640	60,337,258	59,722,147
Weighted average number of common shares outstanding— diluted	60,538,319	59,769,640	60,337,258	59,722,147
Comprehensive loss:
Net loss	$ (102,854)	$ (160,325)	$ (211,337)	$ (307,153)
Other comprehensive items:
Unrealized gain (loss) on marketable securities	96	(556)	123	4,562
Total comprehensive loss	(102,758)	(160,881)	(211,214)	(302,591)
Product Revenue [Member]
Total revenue	600	2,460	2,289	5,754
Collaboration Revenue - Related Party [Member]
Total revenue	7,420		13,633
Other Collaboration Revenue [Member]
Total revenue	$ 634	$ 14	$ 634	$ 14

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Cash flows from operating activities
Net loss	$ (211,337)	$ (307,153)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	30,865	31,731
Premium on marketable securities	(135)	(71)
Amortization of discount on marketable securities	(3,491)	(7,570)
Depreciation expense	647	654
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	3,082	4,505
Collaboration receivable - related party	73,066	(1,430)
Other long-term assets	248	(2,119)
Right-of-use operating asset	3,238	2,972
Operating lease liabilities, current	(3,754)	82
Operating lease liabilities, non-current	0	(3,488)
Accounts payable	(1,668)	(9,566)
Accrued expenses and other liabilities	(9,030)	6,253
Net cash used in operating activities	(118,269)	(285,200)
Cash flows from investing activities
Proceeds from sales and maturities of marketable securities	398,986	630,452
Purchases of marketable securities	(259,936)	(389,655)
Purchases of property and equipment	0	(337)
Net cash provided by investing activities	139,050	240,460
Cash flows from financing activities
Proceeds from stock option exercises and employee stock purchase plan issuances	1,585	4,156
Payments of offering costs	(117)	0
Proceeds from public offerings of common stock, net of commissions and underwriting discounts	8,163	0
Payment of employee tax obligations related to vesting of restricted stock units	(3)	(637)
Net cash provided by financing activities	9,628	3,519
Net increase (decrease) in cash, cash equivalents and restricted cash	30,409	(41,221)
Cash, cash equivalents and restricted cash at beginning of period	72,324	163,969
Cash, cash equivalents and restricted cash at end of period	102,733	122,748
Supplemental disclosure of non-cash operating activities
Purchases of property and equipment included in accounts payable	$ 0	$ 36

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]
Balances at Dec. 31, 2022	$ 1,252,599	$ 6	$ (400)	$ 3,291,369	$ (10,206)	$ (2,028,170)
Balances, Shares at Dec. 31, 2022		59,509,125	3,033
Issuance of common stock from exercises of stock options, Amount	438			438
Issuance of common stock from exercises of stock options, Shares		52,058
Issuance of common stock under the employee stock purchase plan	2,863			2,863
Issuance of common stock under the employee stock purchase plan, Shares		76,105
Stock-based compensation expense	19,568			19,568
Change in unrealized loss on available-for-sale securities	5,118				5,118
Vesting of restricted stock units, net of employee tax obligations	(629)			(629)
Vesting of restricted stock units, net of employee tax obligations, Shares		124,713
Net loss	(146,828)					(146,828)
Balances at Mar. 31, 2023	1,133,129	$ 6	$ (400)	3,313,609	(5,088)	(2,174,998)
Balance, Shares at Mar. 31, 2023		59,762,001	3,033
Balances at Dec. 31, 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
Net loss	(307,153)
Balances at Jun. 30, 2023	984,376	$ 6	$ (400)	3,325,737	(5,644)	(2,335,323)
Balance, Shares at Jun. 30, 2023		59,796,005	3,033
Balances at Mar. 31, 2023	1,133,129	$ 6	$ (400)	3,313,609	(5,088)	(2,174,998)
Balances, Shares at Mar. 31, 2023		59,762,001	3,033
Issuance of common stock from exercises of stock options, Amount	855			855
Issuance of common stock from exercises of stock options, Shares		20,032
Stock-based compensation expense	11,281			11,281
Change in unrealized loss on available-for-sale securities	(556)				(556)
Vesting of restricted stock units, net of employee tax obligations	(8)			(8)
Vesting of restricted stock units, net of employee tax obligations, Shares		13,972
Net loss	(160,325)					(160,325)
Balances at Jun. 30, 2023	984,376	$ 6	$ (400)	3,325,737	(5,644)	(2,335,323)
Balance, Shares at Jun. 30, 2023		59,796,005	3,033
Balances at Dec. 31, 2023	799,530	$ 6	$ (400)	3,370,397	(814)	(2,569,659)
Balances, Shares at Dec. 31, 2023		60,043,643	3,033
Issuance of common stock from exercises of stock options, Amount	52			52
Issuance of common stock from exercises of stock options, Shares		7,142
Issuance of common stock under the employee stock purchase plan	1,507			1,507
Issuance of common stock under the employee stock purchase plan, Shares		61,402
Stock-based compensation expense	13,170			13,170
Change in unrealized loss on available-for-sale securities	27				27
Vesting of restricted stock units, net of employee tax obligations	(2)			(2)
Vesting of restricted stock units, net of employee tax obligations, Shares		69,844
Net loss	(108,483)					(108,483)
Balances at Mar. 31, 2024	705,801	$ 6	$ (400)	3,385,124	(787)	(2,678,142)
Balance, Shares at Mar. 31, 2024		60,182,031	3,033
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
Net loss	(211,337)
Balances at Jun. 30, 2024	628,062	$ 6	$ (400)	3,410,143	(691)	(2,780,996)
Balance, Shares at Jun. 30, 2024		60,894,934	3,033
Balances at Mar. 31, 2024	705,801	$ 6	$ (400)	3,385,124	(787)	(2,678,142)
Balances, Shares at Mar. 31, 2024		60,182,031	3,033
Issuance of common stock from exercises of stock options, Amount	26			26
Issuance of common stock from exercises of stock options, Shares		2,920
Stock-based compensation expense	16,947			16,947
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 loss on available-for-sale securities	96				96
Vesting of restricted stock units, net of employee tax obligations	(1)			(1)
Vesting of restricted stock units, net of employee tax obligations, Shares		9,983
Net loss	(102,854)					(102,854)
Balances at Jun. 30, 2024	$ 628,062	$ 6	$ (400)	$ 3,410,143	$ (691)	$ (2,780,996)
Balance, Shares at Jun. 30, 2024		60,894,934	3,033

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (102,854)	$ (108,483)	$ (160,325)	$ (146,828)	$ (211,337)	$ (307,153)

Insider Trading Arrangements

Insider Trading Arrangements	6 Months Ended
	Jun. 30, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Nature of the Business

Nature of the Business	6 Months Ended
	Jun. 30, 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 approved in the U.S. for the treatment of PPD in individuals 15 years old and older. The Company launched ZULRESSO commercially in the U.S. in June 2019. ZULRESSO may only be administered in qualified, medically-supervised healthcare settings. Brexanolone is chemically identical to allopregnanolone, a naturally occurring neuroactive steroid that, like zuranolone, acts as a positive allosteric modulator of GABA A receptors. Additionally, on August 4, 2023, the FDA issued a complete response letter (“CRL”) related to the Company’s new drug application (“NDA”) for zuranolone for the treatment of major depressive disorder (“MDD”). The CRL stated that the NDA did not provide substantial evidence of effectiveness to support the approval of zuranolone for the treatment of MDD and that one or more additional clinical trials will be needed. The Company and Biogen MA Inc. (“BIMA”) and Biogen International GmbH (collectively with BIMA, “Biogen”) are continuing to seek feedback from the FDA and are evaluating next steps. The Company has a portfolio of product candidates with a current focus on modulating two critical central nervous system (“CNS”) receptor systems, GABA and NMDA. The GABA receptor family, which is recognized as the major inhibitory neurotransmitter in the CNS, mediates downstream neurologic and bodily function via activation of 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. Alongside the Company’s postpartum depression commercial products, it is targeting diseases and disorders of the brain across its pipeline. The Company was incorporated under the laws of the State of Delaware on April 16, 2010, and commenced operations on January 19, 2011 as Sterogen Biopharma, Inc. On September 13, 2011, the Company changed its name to Sage Therapeutics, Inc. Risks and Uncertainties The Company is subject to risks and uncertainties common to companies in the biopharmaceutical industry, including, but not limited to, the risks associated with developing product candidates at each stage of non-clinical and clinical development; the challenges associated with gaining regulatory approval of such product candidates; the risks associated with the marketing and sale of pharmaceutical products; the potential for development by third parties of new technological innovations that may compete with the Company’s products and product candidates; the dependence on key personnel; the challenges of protecting proprietary technology; the need to comply with government regulations; the high costs of drug development; the uncertainty of being able to secure additional capital when needed to fund operations; and the direct or indirect impacts of the macroeconomic environment and geopolitical events on its development activities, operations and financial condition. The product candidates developed by the Company require approvals from the FDA or foreign regulatory authorities prior to commercial sales. There can be no assurance that the current and future product candidates of the Company will receive, or that the Company’s current products, ZULRESSO and ZURZUVAE, will maintain, the necessary approvals. If the Company fails to successfully complete clinical development and generate results sufficient to file for regulatory approval or is denied approval or approval is delayed for any of its product candidates, such occurrences may have a material adverse impact on the Company’s business and its financial condition. The Company is also subject to additional risks and uncertainties arising from changes to the macroeconomic environment and geopolitical events. U.S. and global financial markets have experienced volatility and disruption due to macroeconomic and geopolitical events such as rising inflation, the risk of a recession and ongoing conflicts in other countries. In addition, if equity and credit markets deteriorate, it may make any future debt or equity financing more difficult to obtain on favorable terms, and potentially more dilutive to its existing stockholders. The Company cannot predict at this time to what extent it and its collaborators, employees, suppliers, contract manufacturers and/or vendors could potentially be negatively impacted by these events. Going Concern Under Accounting Standards Update (“ASU”) No. 2014-15, Presentation of Financial Statements—Going Concern (Subtopic 205-40), the Company has the responsibility to evaluate whether conditions and/or events raise substantial doubt about its ability to meet its future financial obligations as they become due within one year after the date that the financial statements are issued. The Company has incurred losses and negative cash flows from operations in each year since its inception, except for net income of $ 606.1 million for the year ended December 31, 2020, reflecting revenue recognized under a collaboration and license agreement with Biogen (the “Biogen Collaboration Agreement”). As of June 30, 2024, the Company had an accumulated deficit of $ 2.8 billion. Until such time, if ever, as the Company can generate substantial product revenue and/or collaboration revenue and achieve sustained profitability, the Company expects to finance its cash needs through a combination of equity offerings, debt financings, collaborations, strategic alliances, licensing arrangements and other sources of funding. If the Company is unable to raise additional funds through equity or debt financings or other sources of funding when needed, the Company may be required to delay, limit, reduce or terminate product development or future commercialization efforts or grant rights to develop and market products or product candidates that the Company would otherwise prefer to develop and market itself. The Company expects that, based on its current operating plans, the Company’s existing cash, cash equivalents and marketable securities will be sufficient to fund its currently planned operations for at least the next 12 months from the filing date of these unaudited interim condensed consolidated financial statements (“condensed consolidated financial statements”). T he 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	6 Months Ended
	Jun. 30, 2024
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies The following is a summary of significant accounting policies followed in the preparation of these condensed consolidated financial statements. Basis of Presentation The condensed consolidated financial statements of the Company included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission. Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) have been condensed or omitted from this report, as is permitted by such rules and regulations. Accordingly, these condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements as of and for the year ended December 31, 2023, included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023. The condensed consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements. In the opinion of the Company’s management, the accompanying condensed consolidated financial statements contain all adjustments, consisting of only normal recurring adjustments, necessary for a fair statement of its financial position as of June 30, 2024, its results of operations and comprehensive loss for the three and six months ended June 30, 2024 and 2023, its cash flows for the six months ended June 30, 2024 and 2023, and its statements of changes in stockholders’ equity for the three and six months ended June 30, 2024 and 2023. The consolidated balance sheet at December 31, 2023 was derived from audited financial statements, but does not include all disclosures required by GAAP. The results for the three and six months ended June 30, 2024 are not necessarily indicative of the results for the year ending December 31, 2024, or for any future period. Principles of Consolidation The condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries as disclosed in Note 2, Summary of Significant Accounting Policies , within the “Notes to Consolidated Financial Statements” accompanying its Annual Report on Form 10-K for the year ended December 31, 2023 . Intercompany accounts and transactions have been eliminated. Use of Estimates The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting period . Research and Development Costs and Accruals Research and development expenses are comprised of costs incurred in performing research and development activities, including salaries and benefits, overhead costs, depreciation, contract services and other related costs. Research and development costs are expensed to operations as the related obligation is incurred. The Company has entered into various research and development contracts with research institutions and other companies both inside and outside of the U.S. These agreements are generally cancelable, and related costs are recorded as research and development expenses as incurred. The Company records accruals for estimated ongoing research and development costs. When billing terms under these contracts do not coincide with the timing of when the work is performed, the Company is required to make estimates of outstanding obligations to those third parties as of the end of the reporting period. Any accrual estimates are based on a number of factors, including the Company’s knowledge of the progress towards completion of the research and development activities, invoicing to date under the contracts, communication from the research institution or other companies of any actual costs incurred during the period that have not yet been invoiced, and the costs included in the contracts. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from the estimates made by the Company. The historical accrual estimates made by the Company have not been materially different from the actual costs. Revenue Recognition Under Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers (“Topic 606”), an entity recognizes revenue when or as performance obligations are satisfied by transferring control of promised goods or services to a customer, in an amount that reflects the consideration that the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of Topic 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price, including variable consideration, if any; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. Arrangements that include rights to additional goods or services that are exercisable at a customer’s discretion are generally considered options. The Company assesses if these options provide a material right to the customer and if so, they are considered performance obligations. The exercise of a material right may be accounted for as a contract modification or as a continuation of the contract for accounting purposes. Topic 606 applies to all contracts with customers, except for contracts that are within the scope of other standards, such as collaboration arrangements. For contracts determined to be within the scope of Topic 606, the Company assesses whether the goods or services promised within each contract are distinct to identify those that are performance obligations. This assessment involves subjective determinations and requires management to make judgments about the individual promised goods or services and whether such are separable from the other aspects of the contractual relationship. Promised goods and services are considered distinct provided that: (i) the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer and (ii) the entity’s promise to transfer the good or service to the customer is separately identifiable from other promises in the contract. The Company allocates the transaction price (the amount of consideration it expects to be entitled to from a customer in exchange for the promised goods or services) to each performance obligation and recognizes the associated revenue when (or as) each performance obligation is satisfied. The Company’s estimate of the transaction price for each contract includes all variable consideration to which the Company expects to be entitled. Product Revenue, Net The Company generates product revenue from the sale of ZULRESSO to a limited number of specialty distributors and specialty pharmacy providers. The Company recognizes product revenue, net of variable consideration related to certain allowances and accruals that are determined using the expected value method, in its condensed consolidated financial statements at the point in time when control transfers to the customer, which is typically when the product has been delivered to the customer’s location. The amount included in the transaction price is constrained to the amount for which it is probable that a significant reversal of cumulative revenue recognized will not occur. The Company’s only performance obligation identified for ZULRESSO is to deliver the product to the location specified by the customer’s order. The Company records shipping and handling costs associated with delivery of product to its customers within selling, general and administrative expenses on its condensed consolidated statements of operations and comprehensive loss. The Company expenses incremental costs of obtaining a contract as incurred if the expected amortization period of the asset would be less than one year. If the Company were to incur incremental costs with an amortization period greater than a year, such costs would be capitalized as contract assets, as they are expected to be recovered, and would be expensed by amortizing on a systematic basis that is consistent with the transfer to the customer of the goods or services to which the asset relates. The Company did not have any contract assets (unbilled receivables) at June 30, 2024, as customer invoicing generally occurs before or at the time of revenue recognition. The Company did not have any contract liabilities at June 30, 2024, as the Company did not receive any payments in advance of satisfying its performance obligations to its customers. Amounts billed or invoiced that are considered trade accounts receivable are included in prepaid expenses and other current assets on the condensed consolidated balance sheets. As of June 30, 2024 and December 31, 2023, the Company had not provided any allowance for bad debts against the trade accounts receivable, and the amount of trade accounts receivable was not significant. The Company records reserves, based on contractual terms, for the following components of variable consideration related to product sold during the reporting period, as well as its estimate of product that remains in the distribution channel inventory of its customers at the end of the reporting period. On a quarterly basis, the Company updates its estimates, if necessary, and records any material adjustments in the period they are identified. Chargebacks : The Company estimates chargebacks from its customers who directly purchase the product from the Company for discounts resulting from contractual commitments to sell products to eligible healthcare settings at prices lower than the list prices charged to its customers. Customers charge the Company for the difference between what they pay to the Company for the product and the selling price to the eligible healthcare settings. Reserves for chargebacks consist of credits that the Company expects to issue for units that remain in the distribution channel inventories at the end of each reporting period that the Company expects will be sold to eligible healthcare settings, and chargebacks that customers have claimed, but for which the Company has not yet issued a credit. Government Rebates : The Company is subject to discount obligations under government programs, including Medicaid. The Company records reserves for rebates in the same period the related product revenue is recognized, resulting in a reduction of ZULRESSO product revenue and a current liability that is included in accrued expenses on its condensed consolidated balance sheets. The Company’s liability for these rebates consists of invoices received for claims from prior quarters that have not been paid or for which an invoice has not yet been received, estimates of claims for the current quarter, and estimates of future claims that will be made for product that has been recognized as revenue, but which remains in the distribution channel at the end of each reporting period. Trade Discounts and Allowances : The Company generally provides customary invoice discounts on ZULRESSO sales to its customers for prompt payment and the Company pays fees for sales order management, data, and distribution services. The Company estimates its customers will earn these discounts and fees and deducts these discounts and fees in full from gross ZULRESSO revenue and accounts receivable at the time the Company recognizes the related revenue. Financial Assistance : The Company provides voluntary financial assistance programs to patients with commercial insurance that have coverage and reside in states that allow financial assistance. The Company estimates the financial assistance amounts for ZULRESSO and records any such amounts within accrued expenses on its condensed consolidated balance sheets. The calculation of the accrual for financial assistance is based on an estimate of claims and the cost per claim that the Company expects to receive using demographics for patients who have registered and been approved for assistance. Any adjustments are recorded in the same period the related revenue is recognized, resulting in a reduction of product revenue and the establishment of a current liability, which is included as a component of accrued expenses on the condensed consolidated balance sheets. Product Returns : Consistent with industry practice, the Company offers product return rights to customers for damaged, defective or expiring product, provided it is within a specified period around the product expiration date as set forth in the Company’s return goods policy. The Company estimates the amount of its product sales that may be returned by its customers and records this estimate as a reduction of revenue in the period the related product revenue is recognized, as well as a reserve within accrued expenses on the condensed consolidated balance sheets. Product returns have not been significant to date and are not expected to be significant in the future. License, Milestone, and Collaboration Revenue In assessing whether a promised good or service is distinct in the evaluation of a collaboration or license arrangement subject to Topic 606, the Company considers factors such as the research, manufacturing and commercialization capabilities of the collaboration partner and the availability of the associated expertise in the general marketplace. The Company also considers the intended benefit of the contract in assessing whether a promised good or service is separately identifiable from other promises in the contract. If a promised good or service is not distinct, the Company is required to combine that good or service with other promised goods or services until it identifies a bundle of goods or services that is distinct. The transaction price is then determined and allocated to the identified performance obligations in proportion to their standalone selling prices (“SSP”) on a relative SSP basis. SSP is determined at contract inception and is not updated to reflect changes between contract inception and when the performance obligations are satisfied. Determining the SSP for performance obligations requires significant judgment. In developing the SSP for a performance obligation, the Company considers applicable market conditions and relevant entity-specific factors, including factors that were contemplated in negotiating the agreement with the customer and estimated costs. In certain circumstances, the Company may apply the residual method to determine the SSP of a good or service if the SSP is considered highly variable or uncertain. The Company validates the SSP for performance obligations by evaluating whether changes in the key assumptions used to determine the SSP will have a significant effect on the allocation of arrangement consideration between multiple performance obligations. If the consideration promised in a contract includes a variable amount, the Company estimates the amount of consideration to which it will be entitled in exchange for transferring the promised goods or services to a customer. The Company determines the amount of variable consideration by using the expected value method or the most likely amount method. The Company includes the unconstrained amount of estimated variable consideration in the transaction price. The amount included in the transaction price is constrained to the amount for which it is probable that a significant reversal of cumulative revenue recognized will not occur. At the end of each subsequent reporting period, the Company re-evaluates the estimated variable consideration included in the transaction price and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis in the period of adjustment. If an arrangement includes development and regulatory milestone payments, the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s control or the licensee’s control, such as regulatory approvals, are generally not considered probable of being achieved until those approvals are received. In determining the transaction price, the Company adjusts consideration for the effects of the time value of money if the timing of payments provides the Company with a significant benefit of financing. The Company does not assess whether a contract has a significant financing component if the expectation at contract inception is such that the period between payment by the licensees and the transfer of the promised goods or services to the licensees will be one year or less. The Company assessed its arrangements with Shionogi & Co., Ltd. (“Shionogi”) and Biogen and concluded that a significant financing component does not exist for either arrangement. For arrangements with licenses of intellectual property that include sales-based royalties or milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties or milestone payments relate, the Company recognizes royalty revenue and sales-based milestones at the later of (i) when the related sales occur, or (ii) when the performance obligation to which the royalty or milestone payment has been allocated has been satisfied. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) each performance obligation is satisfied at a point in time or over time, and if over time this is based on the use of an output or input method. Revenue from the Company’s collaboration agreement with Shionogi has come from initial, upfront consideration upon execution of the agreement and for the supply of drug product for Shionogi’s clinical trials. Revenue from the Company’s collaboration agreement with Biogen has come from initial, upfront consideration related to the execution of the Biogen Collaboration Agreement, milestone payments and the Company’s share of ZURZUVAE revenues under the elements of the arrangement accounted for under ASC Topic 808 Collaborative Arrangements (“Topic 808”). For additional information, see the Collaborative Arrangements section below and refer to Note 7, Collaboration Agreements . Collaborative Arrangements The Company analyzes its collaboration arrangements to assess whether such arrangements involve joint operating activities performed by parties that are both active participants in the activities and exposed to significant risks and rewards dependent on the commercial success of such activities and therefore within the scope of Topic 808. This assessment is performed throughout the life of the arrangement based on changes in the responsibilities of all parties in the arrangement. For collaboration arrangements within the scope of Topic 808 that contain multiple elements, the Company first determines which elements of the collaboration are deemed to be within the scope of Topic 808 and which elements of the collaboration are more reflective of a vendor-customer relationship and therefore within the scope of Topic 606. For elements of collaboration arrangements that are accounted for pursuant to Topic 808, an appropriate recognition method is determined and applied consistently, either by analogy to authoritative accounting literature or by applying a reasonable and rational policy election. For those elements of the arrangement that are accounted for pursuant to Topic 606, the Company applies the five-step model described above, and presents the arrangement as license and milestone revenue or other collaboration revenue in the condensed consolidated statements of operations and comprehensive loss. For collaboration arrangements that are within the scope of Topic 808, the Company evaluates the income statement classification for presentation of amounts due from or owed to other participants associated with multiple activities in a collaboration arrangement based on the nature of each separate activity. Payments or reimbursements that are the result of a collaborative relationship instead of a vendor-customer relationship are recorded as an increase to collaboration revenue, an increase to or reduction of cost of revenues, research and development expense, or selling, general and administrative expense, depending on the nature of the activity. For additional information relating to the accounting for the co-commercialization of ZURZUVAE in the U.S. with Biogen under Topic 808, refer to Note 7, Collaboration Agreements . Fair Value Measurements Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Financial assets and liabilities carried at fair value are classified and disclosed in one of the following three categories: Level 1 — Quoted market prices in active markets for identical assets or liabilities. Level 2 — Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The Company’s cash equivalents and marketable securities at June 30, 2024 and December 31, 2023 were carried at fair value, determined according to the fair value hierarchy; see Note 3, Fair Value Measurements . The carrying amounts reflected in the condensed consolidated balance sheets for the collaboration receivable – related party, accounts payable and accrued expenses approximate their fair values due to their short-term maturities at June 30, 2024 and December 31, 2023 , respectively. Recently Issued 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 does not expect ASU 2023-07 to have a material impact on the Company’s condensed consolidated financial statements and related disclosures upon adoption. In December 2023, the 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 condensed consolidated financial statements and related disclosures.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 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 June 30, 2024 and December 31, 2023. The following tables summarize the Company’s cash equivalents and marketable securities as of June 30, 2024 and December 31, 2023: June 30, 2024 Total Quoted Significant Significant (in thousands) Cash equivalents: Money market funds $ 93,902 $ 93,902 $ — $ — U.S. commercial paper 4,972 — 4,972 — Total cash equivalents 98,874 93,902 4,972 — Marketable securities: U.S. government securities 84,508 — 84,508 — U.S. corporate bonds 205,394 — 205,394 — International corporate bonds 109,490 — 109,490 — U.S. commercial paper 67,154 — 67,154 — International commercial paper 45,109 — 45,109 — U.S. certificates of deposit 2,203 — 2,203 — U.S. municipal securities 33,034 — 33,034 — Total marketable securities 546,892 — 546,892 — $ 645,766 $ 93,902 $ 551,864 $ — 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 six months ended June 30, 2024 and 2023 , there were no transfers among the Level 1, Level 2 and Level 3 categories.

Investments

Investments	6 Months Ended
	Jun. 30, 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 June 30, 2024 and December 31, 2023: June 30, 2024 Amortized Gross Unrealized Gross Unrealized Credit Losses Fair Value (in thousands) Assets: U.S. government securities $ 84,623 $ — $ ( 115 ) $ — $ 84,508 U.S. corporate bonds 205,746 6 ( 358 ) — 205,394 International corporate bonds 109,641 15 ( 166 ) — 109,490 U.S. commercial paper 67,152 3 ( 1 ) — 67,154 International commercial paper 45,109 1 ( 1 ) — 45,109 U.S. certificates of deposit 2,203 — — — 2,203 U.S. municipal securities 33,109 — ( 75 ) — 33,034 $ 547,583 $ 25 $ ( 716 ) $ — $ 546,892 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 June 30, 2024 and December 31, 2023, the Company had $ 3.8 million and $ 4.2 million, respectively, of accrued interest receivable relating to the Company’s available-for-sale securities which is included within prepaid expenses and other current assets in the accompanying condensed consolidated balance sheets . No accrued interest receivable was written off during the three and six months ended June 30, 2024 and 2023. Realized gains or losses were immaterial for the three and six months ended June 30, 2024 and 2023. 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 June 30, 2024 and December 31, 2023: June 30, 2024 Less than 12 months Greater than 12 months Total Fair Unrealized Fair Unrealized Fair Unrealized (in thousands) U.S. government securities $ 46,179 $ ( 44 ) $ 33,425 $ ( 71 ) $ 79,604 $ ( 115 ) U.S. corporate bonds 165,291 ( 246 ) 30,021 ( 112 ) 195,312 ( 358 ) International corporate bonds 79,172 ( 109 ) 19,985 ( 57 ) 99,157 ( 166 ) U.S. commercial paper 12,887 ( 1 ) — — 12,887 ( 1 ) International commercial paper 3,908 ( 1 ) — — 3,908 ( 1 ) U.S. municipal securities 14,818 ( 31 ) 18,216 ( 44 ) 33,034 ( 75 ) $ 322,255 $ ( 432 ) $ 101,647 $ ( 284 ) $ 423,902 $ ( 716 ) 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 June 30, 2024 and December 31, 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. As of June 30, 2024, the Company does not intend to sell those investments and it is not probable that the Company will be required to sell the investments before recovery of their amortized cost basis. As of June 30, 2024 , all marketable securities held by the Company had remaining contractual maturities of one year or less, except for U.S. corporate bonds, international corporate bonds and U.S. municipal securities with a fair value of $ 43.4 million and maturities of one to two years . As of December 31, 2023 , all marketable securities held by the Company had remaining contractual maturities of one year or less, except for U.S. government securities, U.S. corporate bonds, international corporate bonds and U.S. municipal securities with a fair value of $ 110.3 million and maturities of one to two years . All marketable securities, including those with remaining contractual maturities of more than one year, are classified as current assets on the balance sheet because they are considered to be “available-for-sale” and the Company can convert them into cash to fund current operations . There have been no impairments of the Company’s assets measured and carried at fair value during the six months ended June 30, 2024 and the year ended December 31, 2023 .

Accrued Expenses

Accrued Expenses	6 Months Ended
	Jun. 30, 2024
Payables and Accruals [Abstract]
Accrued Expenses	5. Accrued Expenses The following table summarizes accrued expenses as of June 30, 2024 and December 31, 2023: June 30, December 31, 2024 2023 (in thousands) Accrued research and development costs $ 33,753 $ 26,040 Restructuring 762 10,589 Employee-related 14,297 21,339 Professional services 9,726 8,589 Other 444 707 $ 58,982 $ 67,264

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	6. Commitments and Contingencies Operating Leases The Company leases office space and certain equipment. All of the leases recorded on the condensed consolidated balance sheets are operating leases. The Company’s active leases have remaining lease terms of up to one year . Some of the leases include options to extend the leases for up to five years . These options were not included for the purpose of determining the right-of-use assets and associated lease liabilities as the Company determined that the renewal of these leases is not reasonably certain so only the original lease term was taken into consideration. The leases do not include any restrictions or covenants that had to be accounted for under the lease guidance. The Company leases office space in two multi-tenant buildings in Cambridge, Massachusetts, consisting of 63,017 square feet in the first building, the Company’s current headquarters at 215 First Street, Cambridge, Massachusetts, under an operating lease that will expire on August 31, 2024 (the “First Building Lease”) and 40,419 square feet in the second building, at 245 First Street, Cambridge, Massachusetts, under an operating lease that will expire on August 31, 2024 (the “Second Building Lease”); and in a multi-tenant building in Raleigh, North Carolina, consisting of 15,525 square feet under an operating lease that will expire on November 30, 2024 . In January 2024, the Company entered into a lease agreement (the “New Lease”) with 55 Cambridge Parkway, LLC, a Delaware limited liability company (the “Landlord”), pursuant to which the Company will lease approximately 30,567 square feet of office space located at 55 Cambridge Parkway, Cambridge, Massachusetts (the “New Premises”). The Company intends to relocate its corporate headquarters to the New Premises upon the expiration on August 31, 2024 of the First Building Lease and the Second Building Lease, each in accordance with its terms. The term of the New Lease will commence on the later of (1) September 1, 2024 , or (2) the date on which improvements to the New Premises are, or are deemed to be, substantially completed (the “Commencement Date”). The Company’s obligation for the payment of rent for the New Premises begins six months after the Commencement Date (the “Rent Commencement Date”). As of June 30, 2024, a lease commencement date in accordance with ASC 842, Leases , had not occurred, as such no right-of-use asset or lease liability has been recorded. The New Lease has an initial term of approximately sixty-six months , measured from the Commencement Date (the “New Lease Term”). The monthly base rent due under the New Lease shall initially be $ 224,158 per month for the first year following the Rent Commencement Date and is scheduled to increase by approximately 3 % per annum for each subsequent year of the New Lease Term. The Company has the option to extend the New Lease one time for an additional five-year period , subject to the terms therein. The Lease also provides for a construction allowance (the “Allowance”) not to exceed approximately $ 3.4 million to be applied to the construction costs of the New Premises. The Allowance must be used on or before the one-year anniversary of the Commencement Date or will be deemed forfeited with no further obligation by the Landlord. In connection with its entry into the New Lease, and as a security deposit, the Company has provided the Landlord a letter of credit in the amount of approximately $ 1.4 million, classified within other long-term assets on the condensed 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. License Agreements CyDex License Agreement In September 2015, the Company amended and restated its existing commercial license agreement with CyDex Pharmaceuticals, Inc. (“CyDex”), a wholly owned subsidiary of Ligand Pharmaceuticals Incorporated. Under the terms of the commercial license agreement as amended and restated, CyDex has granted to the Company an exclusive license to CyDex’s Captisol drug formulation technology and related intellectual property for the manufacture of pharmaceutical products incorporating brexanolone and the Company’s compound known as SAGE-689, and the development and commercialization of the resulting products for the treatment, prevention or diagnosis of any disease or symptom in humans or animals other than (i) the ocular treatment of any disease or condition with a formulation, including a hormone; (ii) topical ocular treatment of inflammatory conditions; (iii) treatment and prophylaxis of fungal infections in humans; and (iv) any ocular treatment for retinal degeneration. The Company is required to pay a royalty to CyDex on sales of brexanolone and will be required to pay a royalty on any sales of SAGE-689, if such product candidate is successfully developed in the future. Royalty rates are in the low single digits based on levels of net sales. From the effective date of the agreement to June 30, 2024 , the Company has paid to CyDex $ 1.0 million for licensing fees, which was recorded as research and development expense. Under the amended and restated license agreement with CyDex, the Company agreed to make milestone payments on the achievement of clinical development and regulatory milestones in the amount of up to $ 0.8 million in clinical milestones and up to $ 3.8 million in regulatory milestones for each of the first two fields with respect to brexanolone; up to $ 1.3 million in clinical milestones and up to $ 8.5 million in regulatory milestones for each of the third and fourth fields with respect to brexanolone; and up to $ 0.8 million in clinical milestones and up to $ 1.8 million in regulatory milestones for one field with respect to SAGE-689. From the effective date of the agreement to June 30, 2024 , the Company has recorded research and development expense and made cash payments of $ 3.6 million related to these clinical development and regulatory milestones and has recorded an intangible asset and made a cash payment of $ 3.0 million related to these regulatory milestones. For the three and six months ended June 30, 2024 and 2023 , the Company did no t record any expense or intangible asset, or make any milestone payments related to clinical development or regulatory milestones for the brexanolone program or SAGE-689 under the license agreement with CyDex. University of California License Agreements In October 2013, the Company entered into a non-exclusive license agreement with the Regents of the University of California (“the Regents”) under which the Company was granted a non-exclusive license to certain clinical data and clinical material related to brexanolone for use in the development and commercialization of biopharmaceutical products in the licensed field, including status epilepticus and postpartum depression. In May 2014, the license agreement was amended to add the treatment of essential tremor to the licensed field of use, materials and milestone fee provisions of the agreement. The Company paid to the Regents clinical development milestones of $ 0.1 million, prior to December 31, 2015; no other milestones are outstanding under this non-exclusive license agreement. The Company is required to pay royalties of less than 1 % on net sales for a period of fifteen years following the sale of the first product developed using the data and materials, and the Company began to pay these royalties in 2019. The license will terminate on the earlier to occur of (i) 27 years after the effective date or (ii) 15 years after the last-derived product is first commercially sold. In June 2015, the Company entered into an exclusive license agreement with the Regents whereby the Company was granted an exclusive license to certain patent rights related to the use of allopregnanolone to treat various diseases. In exchange for such license, the Company paid an upfront payment of $ 50,000 and was required to make payments of $ 15,000 for annual maintenance fees until the calendar year following the first sale of ZULRESSO. The Company is obligated to make milestone payments following the achievement of specified regulatory and sales milestones of up to $ 0.7 million and $ 2.0 million in the aggregate, respectively. The Company pays royalties at a low single digit percentage of net sales of ZULRESSO, subject to specified minimum annual royalty amounts. Unless terminated by operation of law or by acts of the parties under the terms of the agreement, the license agreement will terminate when the last-to-expire patents or last-to-be abandoned patent applications expire, whichever is later. From the effective date of the agreement to June 30, 2024 , the Company has recorded research and development expense and made cash payments of $ 0.3 million related to these regulatory and sales milestones; and has recorded an intangible asset and made a cash payment of $ 0.5 million related to these regulatory and sales milestones. For the three and six months ended June 30, 2024 and 2023 , the Company did no t record any expense or make any milestone payments under the license agreements with the Regents.

Collaboration Agreements

Collaboration Agreements	6 Months Ended
	Jun. 30, 2024
Shionogi Collaboration Agreement [Member]
Collaboration Agreements	7. Collaboration Agreements Shionogi In June 2018, the Company entered into a strategic collaboration with Shionogi for the clinical development and commercialization of zuranolone for the treatment of MDD and other potential indications in Japan, Taiwan and South Korea (the “Shionogi Territory”). In October 2018, the Company entered into a supply agreement with Shionogi for the Company to supply zuranolone clinical material to Shionogi. Under the terms of the collaboration agreement, Shionogi is responsible for all clinical development and regulatory filings for zuranolone in MDD and other indications in the Shionogi Territory and would be responsible for commercialization of zuranolone in the Shionogi Territory, if zuranolone is successfully developed and obtains marketing approval in any of the countries within the Shionogi Territory. Shionogi was required to make an upfront payment to the Company of $ 90.0 million, and the Company will be eligible to receive additional payments of up to $ 485.0 million if certain regulatory and commercial milestones are achieved by Shionogi. The potential future milestone payments include up to $ 70.0 million for the achievement of specified regulatory milestones, up to $ 30.0 million for the achievement of specified commercialization milestones, and up to $ 385.0 million for the achievement of specified net sales milestones. The Company is eligible to receive tiered royalties on sales of zuranolone in the Shionogi Territory, if development efforts are successful, with tiers averaging in the low to mid- twenty percent range, subject to other terms of the agreement. Shionogi has also granted to the Company certain rights to co-promote zuranolone in Japan. As between the Company and Shionogi, the Company maintains exclusive rights to develop and commercialize zuranolone outside of the Shionogi Territory. The upfront cash payment and any payments for milestones and royalties are non-refundable and non-creditable. Due to the uncertainty of pharmaceutical development and the high historical failure rates generally associated with drug development, the Company may not receive any milestone payments or any royalty payments from Shionogi. The Company concluded that Shionogi meets the definition of a customer because the Company is delivering intellectual property and know-how rights for the zuranolone program in support of territories in which the parties are not jointly sharing the risks and rewards. In addition, the Company determined that the Shionogi collaboration met the requirements to be accounted for as a contract, including that it is probable that the Company will collect the consideration to which the Company is entitled in exchange for the goods or services that will be delivered to Shionogi. The Company determined that the performance obligations in the Shionogi collaboration agreement included the license to zuranolone and the supply of certain materials during the clinical development phase, which includes the supply of active pharmaceutical ingredient (“API”). The performance obligation related to the license to zuranolone was determined to be distinct from other performance obligations and therefore was a separate performance obligation for which control was transferred upon signing. The obligation to provide certain clinical materials, including API for use during the development period, was determined to be a separate performance obligation. Given that Shionogi is not obligated to purchase any minimum amount or quantities of commercial API, the supply of API to Shionogi for commercial use was determined to be an option for Shionogi, rather than a performance obligation of the Company at contract inception and will be accounted for if and when exercised. The Company also determined that there was no separate material right in connection with the supply of API for commercial use as the expected pricing was not at a discount. Given this fact pattern, the Company has concluded the agreement has two performance obligations. Under the clinical supply agreement, the Company is obligated to manufacture and supply to Shionogi (i) clinical quantities of API reasonably required by Shionogi for the development of licensed products in the Shionogi Territory under the collaboration and license agreement and (ii) quantities of drug product reasonably required for use by Shionogi in Phase 1 clinical trials of zuranolone in the Shionogi Territory under the collaboration and license agreement, in the quantities agreed to by the parties. Collaboration revenue from the clinical supply agreement, which excludes the $ 90.0 million upfront payment, pertains to the clinical material sold under the terms of the clinical supply agreement. The Company records the costs related to the clinical supply agreement in research and development expense on its condensed consolidated statements of operations and comprehensive loss. For the three and six months ended June 30, 2024 the Company recognized $ 0.6 million of collaboration revenue from the Company’s agreement with Shionogi. For the three and six months ended June 30, 2023 the Company recognized $ 14 thousand of collaboration revenue 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 standalone selling price of the license performance obligation was $ 90.0 million. The Company recognized the transaction price allocated to the license performance obligation of $ 90.0 million as revenue during the quarter upon delivery of the license to Shionogi and resulting ability of Shionogi to use and benefit from the license, which was in the three months ended June 30, 2018. The remaining transaction price related to the performance obligation for the supply of certain clinical material is not significant. The potential milestone payments that the Company is eligible to receive were excluded from the transaction price, as all milestone amounts were fully constrained based on the probability of achievement. The Company will re-evaluate the transaction price at the end of each reporting period and as uncertain events are resolved or other changes in circumstances occur, and, if necessary, adjust its estimate of the transaction price. Biogen In November 2020, the Company entered into the Biogen Collaboration Agreement to jointly develop and commercialize SAGE-217 products and SAGE-324 products. Concurrently, the Company also entered into a stock purchase agreement with BIMA (the “Biogen Stock Purchase Agreement”) under which BIMA purchased shares of the Company’s common stock. The Biogen Collaboration Agreement became effective on December 28, 2020 (the “Effective Date”). Under the terms of the Biogen Collaboration Agreement, the Company granted Biogen co-exclusive licenses to develop and commercialize SAGE-217 products and SAGE-324 products (each, a “Product Class” and together, the “Licensed Products”) in the U.S., an exclusive license to develop and commercialize SAGE-217 products in all countries of the world other than the U.S. and the Shionogi Territory, and an exclusive license to develop and commercialize SAGE-324 products in all countries of the world other than the U.S. The Company refers to the territories outside the U.S. to which Biogen has rights under the Biogen Collaboration Agreement with respect to the applicable Licensed Product as the “Biogen Territory”. In connection with the effectiveness of the Biogen Collaboration Agreement and the closing of the sale of shares to BIMA in December 2020, the Company received $ 1.5 billion in consideration, comprised of an upfront payment of $ 875.0 million and the $ 650.0 million purchase price for 6,241,473 newly issued shares of the Company’s common stock (the “Biogen Shares”). As a result of the purchase of the Biogen Shares, Biogen is a related party of the Company. The Company 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 in PPD in the U.S. The potential future milestone payments for SAGE-324 products include up to $ 520.0 million for the achievement of specified regulatory and commercial milestones and up to $ 300.0 million for the achievement of specified net sales milestones. A total of $ 150.0 million of these milestone payments are related to the development of SAGE-324 for the treatment of essential tremor. In July 2024, the Company and Biogen announced that the companies do not plan to conduct further clinical development of SAGE-324 in essential tremor, and therefore the Company does not expect to receive those milestone payments. The Company is also eligible to receive tiered royalties on net sales of SAGE-217 products and SAGE-324 products in the Biogen Territory at percentage rates ranging from the high teens to low twenties. Due to the uncertainty of pharmaceutical development and the high historical failure rates generally associated with drug development, and the challenges of launching and commercializing a product, if approved, the Company may never receive any additional milestone payments or any royalty payments under the Biogen Collaboration Agreement. Development and commercialization activities in the U.S. are conducted pursuant to plans agreed to by the Company and Biogen and overseen by a joint steering committee that consists at all times of an equal number of representatives of each party. The Company and Biogen share equally in the costs for development and commercialization, as well as the profits and losses upon FDA approval and commencement of product sales, in the U.S., subject to the Company’s opt-out right described below. Biogen is solely responsible for all development activities and costs related to any development and commercialization of SAGE-217 products and SAGE-324 products for the Biogen Territory, and the Company will receive royalties on any sales in the Biogen Territory, as mentioned above. Biogen is the principal and records sales of SAGE-217 products globally. If approved, the Company will be the principal and record sales of SAGE-324 products in the U.S. and Biogen will be the principal and record sales of SAGE-324 products in the Biogen Territory. The Company is obligated to supply API and bulk drug product for the Biogen Territory and API, bulk drug product and final drug product for the U.S. to support development and commercialization activities. Biogen has the right to assume manufacturing responsibilities for API for the Biogen Territory at any time during the term of the agreement and will, within a reasonable period of time after the Effective Date, assume manufacturing responsibility for bulk drug product for the Biogen Territory. Unless terminated earlier, the Biogen Collaboration Agreement will continue on a Licensed Product-by-Licensed Product and country-by-country basis until the date on which (a) in any country in the Biogen Territory, the royalty term has expired for all Licensed Products in a Product Class in such country, and (b) for the U.S., the parties agree to permanently cease to commercialize all Licensed Products in a Product Class. Biogen also has the right to terminate the Biogen Collaboration Agreement for convenience in its entirety, on a Product Class-by-Product Class basis or as to a particular region, upon advance written notice. The Company has an opt-out right to convert the co-exclusive licenses in the U.S. to an exclusive license to Biogen on a Product Class-by-Product Class basis. Following the exercise of the opt-out right, the Company would no longer share equally in the profits and losses in the U.S. and would be entitled to receive certain royalty payments at percentage rates ranging from the high teens to low twenties and additional sales milestones. The Company concluded that the Biogen Collaboration Agreement and the Biogen Stock Purchase Agreement should be combined and treated as a single arrangement for accounting purposes as the agreements were entered into contemporaneously and in contemplation of one another. The Company determined that the combined agreements had elements that were within the scope of Topic 606 and Topic 808. As of the Effective Date, the Company identified the following promises in the Biogen Collaboration Agreement that were evaluated under the scope of Topic 606: delivery of (i) a co-exclusive license for SAGE-217 products in the U.S.; (ii) an exclusive license for SAGE-217 products in the Biogen Territory; (iii) a co-exclusive license for SAGE-324 products in the U.S.; (iv) an exclusive license for SAGE-324 products in the Biogen Territory; (v) the clinical manufacturing supply of API and bulk drug product for SAGE-217 products in the Biogen Territory; and (vi) the clinical manufacturing supply of API and bulk drug product for SAGE-324 products in the Biogen Territory. The Company also evaluated whether certain options outlined within the Biogen Collaboration Agreement represented material rights that would give rise to a performance obligation and concluded that none of the options convey a material right to Biogen and therefore are not considered separate performance obligations within the Biogen Collaboration Agreement. The Company assessed the above promises and determined that the co-exclusive licenses for SAGE-217 products and SAGE-324 products in the U.S. are reflective of a vendor-customer relationship and therefore represent performance obligations within the scope of Topic 606. The co-exclusive license for SAGE-217 products and SAGE-324 products in the U.S. are considered functional intellectual property and distinct from other promises under the contract. The exclusive licenses for SAGE-217 products and SAGE-324 products in the Biogen Territory are considered functional licenses that are distinct in the context of the Biogen Collaboration Agreement as Biogen can benefit from the licenses on its own or together with other readily available resources. As the co-exclusive licenses in the U.S. and the exclusive licenses in the Biogen Territory are delivered at the same time, they are considered one performance obligation at contract inception. The clinical manufacturing supply of API and bulk drug product for SAGE-217 products and SAGE-324 products for the Biogen Territory are considered distinct in the context of the Biogen Collaboration Agreement as Biogen can benefit from the manufacturing services together with the licenses transferred by the Company at the inception of the agreement. Therefore, each represents a separate performance obligation within a contract with a customer under the scope of Topic 606 at contract inception. The Company determined the transaction price under Topic 606 at the inception of the Biogen Collaboration Agreement to be $ 1.1 billion, consisting of the upfront payment of $ 875.0 million plus $ 232.5 million in excess proceeds from the equity investment under the Biogen Stock Purchase Agreement, when measured at fair value, plus future variable consideration for manufacturing supply of clinical API and bulk drug product for the Biogen Territory. The amount of variable consideration related to the future manufacturing services was not material. At inception, the Company determined that any variable consideration related to clinical development and regulatory or commercial milestones is deemed to be fully constrained and therefore excluded from the transaction price due to the high degree of uncertainty and risk associated with these potential payments, as the Company determined that it could not assert that it was probable that a significant reversal in the amount of cumulative revenue recognized will not occur. The Company also determined that royalties and sales milestones relate solely to the licenses of intellectual property and are therefore excluded from the transaction price under the sales- or usage-based royalty exception of Topic 606. Revenue related to these royalties and sales milestones will only be recognized when the associated sales occur, and relevant thresholds are met. As such, the entirety of the $ 1.1 billion transaction price was allocated to the transfer of the co-exclusive licenses for SAGE-217 products and SAGE-324 products in the U.S. and the exclusive licenses for SAGE-217 products and SAGE-324 products in the Biogen Territory and was recognized as license revenue during the year ended December 31, 2020. In the fourth quarter of 2023 the Company achieved a milestone for the first commercial sale of ZURZUVAE for the treatment of women with PPD in the U.S. and recognized license and milestone revenue – related party of $ 75.0 million during the fourth quarter of the year ended December 31, 2023. Payment of the $ 75.0 million milestone was received during January 2024. During the three and six months ended June 30, 2024 and 2023 , no license and milestone revenue – related party was recognized related to the Biogen Collaboration Agreement. The Company considers the collaborative activities associated with the co-development, co-commercialization, and co-manufacturing of SAGE-217 products and SAGE-324 products in the U.S. to be separate units of account within the scope of Topic 808 as the Company and Biogen are both active participants in the development and commercialization activities and are exposed to significant risks and rewards that are dependent on the development and commercial success of the activities in the arrangement. While Biogen is considered the principal in transactions with customers for the sale of ZURZUVAE globally, the Company is also engaged in significant commercialization activities, including maintaining its own U.S. direct sales force. The Company presents its proportionate share of Biogen’s ZURZUVAE sales to customers in the U.S. as collaboration revenue - related party. Payments to or reimbursements from Biogen related to the agreement of the parties to share equally in all revenue and costs are accounted for as an increase to collaboration revenue, an increase to or reduction of cost of revenues, research and development expenses, or selling, general and administrative expenses, in the condensed consolidated statement of operations and comprehensive loss, depending on the nature of the activity. To record its proportionate share of collaboration revenue from Biogen’s sales of ZURZUVAE to customers in the U.S., the Company utilizes certain information from Biogen, including revenue from the sale of the product and associated reserves on revenue. The following table summarizes the Company’s proportionate share of the activity under the Biogen Collaboration Agreement accounted for under Topic 808, including activities associated with the sale of ZURZUVAE in the U.S., as well as ongoing costs related to the development of SAGE-217 products and SAGE-324 products, as reflected in our condensed consolidated statement of operations and comprehensive loss: Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 (in thousands) (in thousands) Collaboration revenue - related party $ 7,420 $ — $ 13,633 $ — Cost of revenues 1,294 — 2,495 — Research and development expenses 4,943 27,679 11,974 49,851 Selling, general and administrative expenses 13,072 28,755 26,055 47,718 The revenue, cost and expense categories in the table below reflect the following reimbursement amounts to (from) Biogen to account for the sharing of economics under the Biogen Collaboration Agreement: Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 (in thousands) (in thousands) Collaboration revenue - related party $ ( 7,420 ) $ — $ ( 13,633 ) $ — Cost of revenues ( 566 ) — ( 1,128 ) — Research and development expenses ( 3,325 ) ( 22,418 ) ( 8,982 ) ( 39,700 ) Selling, general and administrative expenses 1,019 7,476 3,325 10,510 As of June 30, 2024, the Company recorded a collaboration receivable - related party of $ 9.9 million in the condensed consolidated balance sheet all related to net reimbursement for the amounts due for the three months ended June 30, 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 six months ended June 30, 2024 , no payments were made to Biogen and the Company received $ 93.1 million from Biogen for the amounts due for the three months ended December 31, 2023 and the three months ended March 31, 2024. During the six months ended June 30, 2023 , no payments were made to Biogen and the Company received $ 27.8 million from Biogen for the amounts due for the three months ended December 31, 2022 and the three months ended March 31, 2023. 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.

Common Stock

Common Stock	6 Months Ended
	Jun. 30, 2024
Text Block [Abstract]
Common Stock	8. Common Stock As of June 30, 2024 and December 31, 2023 , the Company had 120,000,000 authorized shares of common stock, par value $ 0.0001 per share. Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders. Common stockholders are entitled to receive dividends, as may be declared by the Board of Directors of the Company (the “Board”), if any. As of June 30, 2024 and December 31, 2023 , no dividends have been declared. As of June 30, 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 June 30, 2024 was $ 0.4 million. Sales Agreement On November 7, 2023, the Company entered into a Sales Agreement (the “Sales Agreement”) with Cowen and Company, LLC, as sales agent (“Cowen”), with respect to an “at the market offering” program pursuant to which the Company may offer and sell shares of its common stock having an aggregate offering price of up to $ 250.0 million (the “Shares”), from time to time through Cowen (the “ATM Offering”). Upon delivery of a placement notice, and subject to the terms and conditions of the Sales Agreement, Cowen may sell the Shares by methods deemed to be an “at the market offering” as defined in Rule 415(a)(4) promulgated under the Securities Act of 1933, as amended. The Company may sell the Shares in amounts and at times to be determined by the Company from time to time subject to the terms and conditions of the Sales Agreement, but the Company has no obligation to sell any of the Shares in the ATM Offering. The Company or Cowen may suspend or terminate the ATM Offering upon notice to the other parties and subject to other conditions. Cowen will act as sales agent on a commercially reasonable efforts basis consistent with its normal trading and sales practices, applicable state and federal laws, rules and regulations, and the rules of The Nasdaq Global Market. The Company has agreed to pay Cowen commission for its service in acting as agent in the sale of the Shares in the amount of up to 3.0 % of the gross proceeds from the sale of the Shares pursuant to the Sales Agreement. During the three months ended June 30, 2024 , the Company sold an aggregate of 700,000 shares under the 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. As of June 30, 2024 , $ 241.7 million of shares remained available for issuance and sale under the Sales Agreement.

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2024
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	9. Stock-Based Compensation Equity Plans On July 2, 2014, the stockholders of the Company approved the 2014 Stock Option and Incentive Plan (the “2014 Plan”), which became effective immediately prior to the completion of the Company’s 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 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 June 30, 2024, the total number of shares underlying outstanding awards under the 2024 Plan, the 2014 Plan and the 2016 Plan was 11,119,248 , and the total number of shares available for future issuance under the 2024 Plan was 5,480,598 shares. On June 16, 2022, the Company’s stockholders approved an amendment to the amended 2014 Employee Stock Purchase Plan (the “ESPP”), which had been previously approved by the Board, to add 300,000 shares of common stock to the ESPP. On June 15, 2023, the Company’s stockholders approved another amendment to the ESPP, which had been previously approved by the Board, to add an additional 500,000 shares of common stock to the ESPP. As amended, a total of 1,082,000 shares of common stock have been authorized for issuance under the ESPP. As of June 30, 2024 , the total number of shares available for future issuance under the ESPP was 574,678 shares. 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 1,277,080 $ 23.50 Vested ( 80,039 ) $ 44.21 Forfeited ( 172,516 ) $ 32.00 Outstanding as of June 30, 2024 4,112,919 $ 30.83 Time-based restricted stock units During the three and six months ended June 30, 2024, the Company granted 24,941 and 882,025 time-based restricted stock units, respectively, to its employees and consultants. During the six months ended June 30, 2023 , the Company granted 330,617 time-based restricted stock units to its employees and consultants. During the three months ended June 30, 2023, the Company did no t grant any time-based restricted stock units. During the three and six months ended June 30, 2024 , there were 10,096 and 80,039 time-based restricted stock units that vested, respectively. The fair value on the date of vesting for the three and six months ended June 30, 2024 was $ 0.1 million and $ 1.7 million, respectively. During the three and six months ended June 30, 2023 , there were 14,144 and 28,577 time-based restricted stock units that vested, respectively. The fair value on the date of vesting for the three and six months ended June 30, 2023 was $ 0.7 million and $ 1.3 million, respectively. As of June 30, 2024, 2,343,027 time-based restricted stock units were both outstanding and unvested, and the total unrecognized stock-based compensation expense related to these awards was $ 28.8 million. Performance restricted stock units During the six months ended June 30, 2024 , the Company granted 395,055 performance restricted stock units to its employees. During the three months ended June 30, 2024 , the Company did no t grant any performance restricted stock units. During the three and six months ended June 30, 2023 , the Company granted 39,603 and 862,321 performance restricted stock units, respectively, to its employees and consultants. The majority of the performance restricted stock units vest upon the achievement of certain clinical and regulatory development milestones related to product candidates and certain commercial milestones. Certain performance restricted stock units vest upon the Company reaching specified measures of total stockholder return. Recognition of stock-based compensation expense associated with performance restricted stock units, except for those with milestones that are measures of total stockholder return, commences when the performance condition is considered probable of achievement, using management’s best estimates, which consider the inherent risk and uncertainty regarding the future outcomes of the milestones. Recognition of stock-based compensation expense associated with performance restricted stock units with milestones that are measures of total stockholder return commences on the grant date and is recorded independently of the vesting outcomes of the grants. As of June 30, 2024 , the achievement of one commercial milestone that is the criteria for vesting of performance restricted stock units was considered probable, but had not been met, and therefore $ 2.8 million of stock-based compensation expense was recognized related to these awards for the three months ended June 30, 2024. As of June 30, 2023, for performance restricted stock units that were outstanding, and other than performance restricted stock units for which the vesting is tied to total stockholder return, the achievement of the milestones that had not been met was considered not probable, and therefore no expense was recognized related to these awards for the three months ended June 30, 2023. During the three and six months ended June 30, 2024 , the Company recorded $ 0.4 million and $ 0.8 million of stock-based compensation expense, respectively, related to performance restricted stock units for which vesting is tied to total stockholder return. During the three and six months ended June 30, 2023 , the Company recorded $ 21,000 and $ 0.3 million of stock-based compensation expense, respectively, related to performance restricted stock units for which vesting is tied to total stockholder return. During the three and six months ended June 30, 2024 , no outstanding performance restricted stock units vested. During the three months ended March 31, 2023, one regulatory development milestone for outstanding performance restricted stock units was achieved. The fair value of the performance restricted stock units that vested upon achievement was $ 5.5 million and the Company recognized stock-based compensation expense related to this milestone of $ 8.5 million. During the three months ended June 30, 2023 , no outstanding performance restricted stock units vested. As of June 30, 2024, 1,769,892 performance restricted stock units were both outstanding and unvested, and the total unrecognized stock-based compensation expense related to these awards was $ 66.5 million. During the three months ended June 30, 2024 , the achievement of one commercial milestone that is the criteria for vesting of performance restricted stock units was considered probable, but had not been met, and therefore $ 2.8 million of stock-based compensation expense was recognized related to these awards for the three months ended June 30, 2024. 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 2,162,855 $ 21.79 Exercised ( 10,062 ) $ 7.69 Forfeited ( 3,243,941 ) $ 85.93 Expired ( 20,564 ) $ 8.92 Outstanding as of June 30, 2024 7,006,329 $ 54.99 5.78 $ — Exercisable as of June 30, 2024 4,278,083 $ 66.73 4.61 $ — As of June 30, 2024, the Company had unrecognized stock-based compensation expense related to its outstanding and unvested time-based stock option awards of $ 40.3 million, which is expected to be recognized over the remaining weighted average vesting period of 2.66 years. The intrinsic value of stock options exercised during the six months ended June 30, 2024 and 2023 was $ 0.1 million and $ 1.9 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 June 30, 2024 and 2023 , for performance-based stock option grants that were outstanding, the achievement of the milestones that had not been met was considered not probable, and therefore no expense has been recognized related to these awards during the six months ended June 30, 2024 and 2023, respectively. During the six months ended June 30, 2024 and 2023 , the Company granted no stock options to purchase shares of common stock that contain performance-based vesting criteria. During the six months ended June 30, 2024 and 2023 , no milestones were achieved under performance-based stock options. As of June 30, 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 six months ended June 30, 2024 and 2023: Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 (in thousands) Research and development $ 6,118 $ 4,496 $ 11,084 $ 13,269 Selling, general and administrative 11,049 7,197 19,781 18,462 $ 17,167 $ 11,693 $ 30,865 $ 31,731 The following table summarizes stock-based compensation expense by award type recognized during the six months ended June 30, 2024 and 2023: Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 (in thousands) Stock options $ 7,724 $ 9,663 $ 15,175 $ 19,678 Restricted stock units 9,223 1,618 14,942 11,171 Employee stock purchase plan 220 412 748 882 $ 17,167 $ 11,693 $ 30,865 $ 31,731 For stock option awards, the fair value is estimated at the grant date using the Black-Scholes option-pricing model, taking into account the terms and conditions upon which stock options are granted. The fair value of the stock options is amortized on a straight-line basis for stock option awards to employees, non-employee directors and non-employee consultants over the requisite service period of the awards. The weighted average grant date fair value per share of stock options granted under the Company’s stock option plans during the six months ended June 30, 2024 and 2023 was $ 14.69 and $ 30.41 , respectively.

Net Loss Per Share

Net Loss Per Share	6 Months Ended
	Jun. 30, 2024
Earnings Per Share [Abstract]
Net Loss Per Share	10. Net Loss Per Share The following table shows the calculation of basic and diluted net loss per share for the six months ended June 30, 2024 and 2023: Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 Basic net loss per share: Numerator: Net loss (in thousands) $ ( 102,854 ) $ ( 160,325 ) $ ( 211,337 ) $ ( 307,153 ) Denominator: Weighted average common stock outstanding 60,538,319 59,769,640 60,337,258 59,722,147 Net loss per share - basic and diluted $ ( 1.70 ) $ ( 2.68 ) $ ( 3.50 ) $ ( 5.14 ) 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 six months ended June 30, 2024 and 2023: Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 Stock options 6,551,329 7,851,925 6,551,329 7,851,925 Restricted stock units 2,343,027 445,421 2,343,027 445,421 Employee stock purchase plan 155,484 87,938 155,484 87,938 9,049,840 8,385,284 9,049,840 8,385,284 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.

Restructuring

Restructuring	6 Months Ended
	Jun. 30, 2024
Restructuring and Related Activities [Abstract]
Restructuring	11. Restructuring In August 2023, the Company implemented a strategic corporate reorganization and reprioritization of its pipeline. The reorganization included a reduction of the Company’s workforce by approximately 40 %, designed to right-size the organization as the Company works to achieve sustained growth and support the commercialization of ZURZUVAE to treat women with PPD. As of June 30, 2024 , the Company has paid substantially all of the accrued restructuring charges. Total restructuring charges incurred to date are $ 32.8 million, which is the total expected amount to be incurred. The following table summarizes activity related to the restructuring accrual during the six months ended June 30, 2024: Restructuring Accrual (in thousands) Balance as of December 31, 2023 $ 10,589 Restructuring expenses incurred ( 597 ) Cash paid ( 9,230 ) Non-cash activity — Balance as of June 30, 2024 $ 762

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 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 the Company’s current products, ZULRESSO and ZURZUVAE, will maintain, the necessary approvals. If the Company fails to successfully complete clinical development and generate results sufficient to file for regulatory approval or is denied approval or approval is delayed for any of its product candidates, such occurrences may have a material adverse impact on the Company’s business and its financial condition. The Company is also subject to additional risks and uncertainties arising from changes to the macroeconomic environment and geopolitical events. U.S. and global financial markets have experienced volatility and disruption due to macroeconomic and geopolitical events such as rising inflation, the risk of a recession and ongoing conflicts in other countries. In addition, if equity and credit markets deteriorate, it may make any future debt or equity financing more difficult to obtain on favorable terms, and potentially more dilutive to its existing stockholders. The Company cannot predict at this time to what extent it and its collaborators, employees, suppliers, contract manufacturers and/or vendors could potentially be negatively impacted by these events.
Going Concern	Going Concern Under Accounting Standards Update (“ASU”) No. 2014-15, Presentation of Financial Statements—Going Concern (Subtopic 205-40), the Company has the responsibility to evaluate whether conditions and/or events raise substantial doubt about its ability to meet its future financial obligations as they become due within one year after the date that the financial statements are issued. The Company has incurred losses and negative cash flows from operations in each year since its inception, except for net income of $ 606.1 million for the year ended December 31, 2020, reflecting revenue recognized under a collaboration and license agreement with Biogen (the “Biogen Collaboration Agreement”). As of June 30, 2024, the Company had an accumulated deficit of $ 2.8 billion. Until such time, if ever, as the Company can generate substantial product revenue and/or collaboration revenue and achieve sustained profitability, the Company expects to finance its cash needs through a combination of equity offerings, debt financings, collaborations, strategic alliances, licensing arrangements and other sources of funding. If the Company is unable to raise additional funds through equity or debt financings or other sources of funding when needed, the Company may be required to delay, limit, reduce or terminate product development or future commercialization efforts or grant rights to develop and market products or product candidates that the Company would otherwise prefer to develop and market itself. The Company expects that, based on its current operating plans, the Company’s existing cash, cash equivalents and marketable securities will be sufficient to fund its currently planned operations for at least the next 12 months from the filing date of these unaudited interim condensed consolidated financial statements (“condensed consolidated financial statements”). T he Company anticipates it will require additional financing to fund its future operations. Even if the Company believes it has sufficient funds for its current or future operating plans, the Company may seek to raise additional capital if market conditions are favorable or in light of other strategic considerations.
Basis of Presentation	Basis of Presentation The condensed consolidated financial statements of the Company included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission. Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) have been condensed or omitted from this report, as is permitted by such rules and regulations. Accordingly, these condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements as of and for the year ended December 31, 2023, included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023. The condensed consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements. In the opinion of the Company’s management, the accompanying condensed consolidated financial statements contain all adjustments, consisting of only normal recurring adjustments, necessary for a fair statement of its financial position as of June 30, 2024, its results of operations and comprehensive loss for the three and six months ended June 30, 2024 and 2023, its cash flows for the six months ended June 30, 2024 and 2023, and its statements of changes in stockholders’ equity for the three and six months ended June 30, 2024 and 2023. The consolidated balance sheet at December 31, 2023 was derived from audited financial statements, but does not include all disclosures required by GAAP. The results for the three and six months ended June 30, 2024 are not necessarily indicative of the results for the year ending December 31, 2024, or for any future period.
Principles of Consolidation	Principles of Consolidation The condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries as disclosed in Note 2, Summary of Significant Accounting Policies , within the “Notes to Consolidated Financial Statements” accompanying its Annual Report on Form 10-K for the year ended December 31, 2023 . Intercompany accounts and transactions have been eliminated.
Use of Estimates	Use of Estimates The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting period .
Research and Development Costs and Accruals	Research and Development Costs and Accruals Research and development expenses are comprised of costs incurred in performing research and development activities, including salaries and benefits, overhead costs, depreciation, contract services and other related costs. Research and development costs are expensed to operations as the related obligation is incurred. The Company has entered into various research and development contracts with research institutions and other companies both inside and outside of the U.S. These agreements are generally cancelable, and related costs are recorded as research and development expenses as incurred. The Company records accruals for estimated ongoing research and development costs. When billing terms under these contracts do not coincide with the timing of when the work is performed, the Company is required to make estimates of outstanding obligations to those third parties as of the end of the reporting period. Any accrual estimates are based on a number of factors, including the Company’s knowledge of the progress towards completion of the research and development activities, invoicing to date under the contracts, communication from the research institution or other companies of any actual costs incurred during the period that have not yet been invoiced, and the costs included in the contracts. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from the estimates made by the Company. The historical accrual estimates made by the Company have not been materially different from the actual costs.
Revenue Recognition	Revenue Recognition Under Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers (“Topic 606”), an entity recognizes revenue when or as performance obligations are satisfied by transferring control of promised goods or services to a customer, in an amount that reflects the consideration that the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of Topic 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price, including variable consideration, if any; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. Arrangements that include rights to additional goods or services that are exercisable at a customer’s discretion are generally considered options. The Company assesses if these options provide a material right to the customer and if so, they are considered performance obligations. The exercise of a material right may be accounted for as a contract modification or as a continuation of the contract for accounting purposes. Topic 606 applies to all contracts with customers, except for contracts that are within the scope of other standards, such as collaboration arrangements. For contracts determined to be within the scope of Topic 606, the Company assesses whether the goods or services promised within each contract are distinct to identify those that are performance obligations. This assessment involves subjective determinations and requires management to make judgments about the individual promised goods or services and whether such are separable from the other aspects of the contractual relationship. Promised goods and services are considered distinct provided that: (i) the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer and (ii) the entity’s promise to transfer the good or service to the customer is separately identifiable from other promises in the contract. The Company allocates the transaction price (the amount of consideration it expects to be entitled to from a customer in exchange for the promised goods or services) to each performance obligation and recognizes the associated revenue when (or as) each performance obligation is satisfied. The Company’s estimate of the transaction price for each contract includes all variable consideration to which the Company expects to be entitled. Product Revenue, Net The Company generates product revenue from the sale of ZULRESSO to a limited number of specialty distributors and specialty pharmacy providers. The Company recognizes product revenue, net of variable consideration related to certain allowances and accruals that are determined using the expected value method, in its condensed consolidated financial statements at the point in time when control transfers to the customer, which is typically when the product has been delivered to the customer’s location. The amount included in the transaction price is constrained to the amount for which it is probable that a significant reversal of cumulative revenue recognized will not occur. The Company’s only performance obligation identified for ZULRESSO is to deliver the product to the location specified by the customer’s order. The Company records shipping and handling costs associated with delivery of product to its customers within selling, general and administrative expenses on its condensed consolidated statements of operations and comprehensive loss. The Company expenses incremental costs of obtaining a contract as incurred if the expected amortization period of the asset would be less than one year. If the Company were to incur incremental costs with an amortization period greater than a year, such costs would be capitalized as contract assets, as they are expected to be recovered, and would be expensed by amortizing on a systematic basis that is consistent with the transfer to the customer of the goods or services to which the asset relates. The Company did not have any contract assets (unbilled receivables) at June 30, 2024, as customer invoicing generally occurs before or at the time of revenue recognition. The Company did not have any contract liabilities at June 30, 2024, as the Company did not receive any payments in advance of satisfying its performance obligations to its customers. Amounts billed or invoiced that are considered trade accounts receivable are included in prepaid expenses and other current assets on the condensed consolidated balance sheets. As of June 30, 2024 and December 31, 2023, the Company had not provided any allowance for bad debts against the trade accounts receivable, and the amount of trade accounts receivable was not significant. The Company records reserves, based on contractual terms, for the following components of variable consideration related to product sold during the reporting period, as well as its estimate of product that remains in the distribution channel inventory of its customers at the end of the reporting period. On a quarterly basis, the Company updates its estimates, if necessary, and records any material adjustments in the period they are identified. Chargebacks : The Company estimates chargebacks from its customers who directly purchase the product from the Company for discounts resulting from contractual commitments to sell products to eligible healthcare settings at prices lower than the list prices charged to its customers. Customers charge the Company for the difference between what they pay to the Company for the product and the selling price to the eligible healthcare settings. Reserves for chargebacks consist of credits that the Company expects to issue for units that remain in the distribution channel inventories at the end of each reporting period that the Company expects will be sold to eligible healthcare settings, and chargebacks that customers have claimed, but for which the Company has not yet issued a credit. Government Rebates : The Company is subject to discount obligations under government programs, including Medicaid. The Company records reserves for rebates in the same period the related product revenue is recognized, resulting in a reduction of ZULRESSO product revenue and a current liability that is included in accrued expenses on its condensed consolidated balance sheets. The Company’s liability for these rebates consists of invoices received for claims from prior quarters that have not been paid or for which an invoice has not yet been received, estimates of claims for the current quarter, and estimates of future claims that will be made for product that has been recognized as revenue, but which remains in the distribution channel at the end of each reporting period. Trade Discounts and Allowances : The Company generally provides customary invoice discounts on ZULRESSO sales to its customers for prompt payment and the Company pays fees for sales order management, data, and distribution services. The Company estimates its customers will earn these discounts and fees and deducts these discounts and fees in full from gross ZULRESSO revenue and accounts receivable at the time the Company recognizes the related revenue. Financial Assistance : The Company provides voluntary financial assistance programs to patients with commercial insurance that have coverage and reside in states that allow financial assistance. The Company estimates the financial assistance amounts for ZULRESSO and records any such amounts within accrued expenses on its condensed consolidated balance sheets. The calculation of the accrual for financial assistance is based on an estimate of claims and the cost per claim that the Company expects to receive using demographics for patients who have registered and been approved for assistance. Any adjustments are recorded in the same period the related revenue is recognized, resulting in a reduction of product revenue and the establishment of a current liability, which is included as a component of accrued expenses on the condensed consolidated balance sheets. Product Returns : Consistent with industry practice, the Company offers product return rights to customers for damaged, defective or expiring product, provided it is within a specified period around the product expiration date as set forth in the Company’s return goods policy. The Company estimates the amount of its product sales that may be returned by its customers and records this estimate as a reduction of revenue in the period the related product revenue is recognized, as well as a reserve within accrued expenses on the condensed consolidated balance sheets. Product returns have not been significant to date and are not expected to be significant in the future. License, Milestone, and Collaboration Revenue In assessing whether a promised good or service is distinct in the evaluation of a collaboration or license arrangement subject to Topic 606, the Company considers factors such as the research, manufacturing and commercialization capabilities of the collaboration partner and the availability of the associated expertise in the general marketplace. The Company also considers the intended benefit of the contract in assessing whether a promised good or service is separately identifiable from other promises in the contract. If a promised good or service is not distinct, the Company is required to combine that good or service with other promised goods or services until it identifies a bundle of goods or services that is distinct. The transaction price is then determined and allocated to the identified performance obligations in proportion to their standalone selling prices (“SSP”) on a relative SSP basis. SSP is determined at contract inception and is not updated to reflect changes between contract inception and when the performance obligations are satisfied. Determining the SSP for performance obligations requires significant judgment. In developing the SSP for a performance obligation, the Company considers applicable market conditions and relevant entity-specific factors, including factors that were contemplated in negotiating the agreement with the customer and estimated costs. In certain circumstances, the Company may apply the residual method to determine the SSP of a good or service if the SSP is considered highly variable or uncertain. The Company validates the SSP for performance obligations by evaluating whether changes in the key assumptions used to determine the SSP will have a significant effect on the allocation of arrangement consideration between multiple performance obligations. If the consideration promised in a contract includes a variable amount, the Company estimates the amount of consideration to which it will be entitled in exchange for transferring the promised goods or services to a customer. The Company determines the amount of variable consideration by using the expected value method or the most likely amount method. The Company includes the unconstrained amount of estimated variable consideration in the transaction price. The amount included in the transaction price is constrained to the amount for which it is probable that a significant reversal of cumulative revenue recognized will not occur. At the end of each subsequent reporting period, the Company re-evaluates the estimated variable consideration included in the transaction price and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis in the period of adjustment. If an arrangement includes development and regulatory milestone payments, the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s control or the licensee’s control, such as regulatory approvals, are generally not considered probable of being achieved until those approvals are received. In determining the transaction price, the Company adjusts consideration for the effects of the time value of money if the timing of payments provides the Company with a significant benefit of financing. The Company does not assess whether a contract has a significant financing component if the expectation at contract inception is such that the period between payment by the licensees and the transfer of the promised goods or services to the licensees will be one year or less. The Company assessed its arrangements with Shionogi & Co., Ltd. (“Shionogi”) and Biogen and concluded that a significant financing component does not exist for either arrangement. For arrangements with licenses of intellectual property that include sales-based royalties or milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties or milestone payments relate, the Company recognizes royalty revenue and sales-based milestones at the later of (i) when the related sales occur, or (ii) when the performance obligation to which the royalty or milestone payment has been allocated has been satisfied. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) each performance obligation is satisfied at a point in time or over time, and if over time this is based on the use of an output or input method. Revenue from the Company’s collaboration agreement with Shionogi has come from initial, upfront consideration upon execution of the agreement and for the supply of drug product for Shionogi’s clinical trials. Revenue from the Company’s collaboration agreement with Biogen has come from initial, upfront consideration related to the execution of the Biogen Collaboration Agreement, milestone payments and the Company’s share of ZURZUVAE revenues under the elements of the arrangement accounted for under ASC Topic 808 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 condensed consolidated statements of operations and comprehensive loss. For collaboration arrangements that are within the scope of Topic 808, the Company evaluates the income statement classification for presentation of amounts due from or owed to other participants associated with multiple activities in a collaboration arrangement based on the nature of each separate activity. Payments or reimbursements that are the result of a collaborative relationship instead of a vendor-customer relationship are recorded as an increase to collaboration revenue, an increase to or reduction of cost of revenues, research and development expense, or selling, general and administrative expense, depending on the nature of the activity. For additional information relating to the accounting for the co-commercialization of ZURZUVAE in the U.S. with Biogen under Topic 808, refer to Note 7, Collaboration Agreements .
Fair Value Measurements	Fair Value Measurements Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Financial assets and liabilities carried at fair value are classified and disclosed in one of the following three categories: Level 1 — Quoted market prices in active markets for identical assets or liabilities. Level 2 — Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The Company’s cash equivalents and marketable securities at June 30, 2024 and December 31, 2023 were carried at fair value, determined according to the fair value hierarchy; see Note 3, Fair Value Measurements . The carrying amounts reflected in the condensed consolidated balance sheets for the collaboration receivable – related party, accounts payable and accrued expenses approximate their fair values due to their short-term maturities at June 30, 2024 and December 31, 2023 , respectively.
Recently Issued Accounting Pronouncements	Recently Issued 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 does not expect ASU 2023-07 to have a material impact on the Company’s condensed consolidated financial statements and related disclosures upon adoption. In December 2023, the 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 condensed consolidated financial statements and related disclosures.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 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 June 30, 2024 and December 31, 2023: June 30, 2024 Total Quoted Significant Significant (in thousands) Cash equivalents: Money market funds $ 93,902 $ 93,902 $ — $ — U.S. commercial paper 4,972 — 4,972 — Total cash equivalents 98,874 93,902 4,972 — Marketable securities: U.S. government securities 84,508 — 84,508 — U.S. corporate bonds 205,394 — 205,394 — International corporate bonds 109,490 — 109,490 — U.S. commercial paper 67,154 — 67,154 — International commercial paper 45,109 — 45,109 — U.S. certificates of deposit 2,203 — 2,203 — U.S. municipal securities 33,034 — 33,034 — Total marketable securities 546,892 — 546,892 — $ 645,766 $ 93,902 $ 551,864 $ — 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)	6 Months Ended
	Jun. 30, 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 June 30, 2024 and December 31, 2023: June 30, 2024 Amortized Gross Unrealized Gross Unrealized Credit Losses Fair Value (in thousands) Assets: U.S. government securities $ 84,623 $ — $ ( 115 ) $ — $ 84,508 U.S. corporate bonds 205,746 6 ( 358 ) — 205,394 International corporate bonds 109,641 15 ( 166 ) — 109,490 U.S. commercial paper 67,152 3 ( 1 ) — 67,154 International commercial paper 45,109 1 ( 1 ) — 45,109 U.S. certificates of deposit 2,203 — — — 2,203 U.S. municipal securities 33,109 — ( 75 ) — 33,034 $ 547,583 $ 25 $ ( 716 ) $ — $ 546,892 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 June 30, 2024 and December 31, 2023: June 30, 2024 Less than 12 months Greater than 12 months Total Fair Unrealized Fair Unrealized Fair Unrealized (in thousands) U.S. government securities $ 46,179 $ ( 44 ) $ 33,425 $ ( 71 ) $ 79,604 $ ( 115 ) U.S. corporate bonds 165,291 ( 246 ) 30,021 ( 112 ) 195,312 ( 358 ) International corporate bonds 79,172 ( 109 ) 19,985 ( 57 ) 99,157 ( 166 ) U.S. commercial paper 12,887 ( 1 ) — — 12,887 ( 1 ) International commercial paper 3,908 ( 1 ) — — 3,908 ( 1 ) U.S. municipal securities 14,818 ( 31 ) 18,216 ( 44 ) 33,034 ( 75 ) $ 322,255 $ ( 432 ) $ 101,647 $ ( 284 ) $ 423,902 $ ( 716 ) 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 )

Accrued Expenses (Tables)

Accrued Expenses (Tables)	6 Months Ended
	Jun. 30, 2024
Payables and Accruals [Abstract]
Summary of Accrued Expenses	The following table summarizes accrued expenses as of June 30, 2024 and December 31, 2023: June 30, December 31, 2024 2023 (in thousands) Accrued research and development costs $ 33,753 $ 26,040 Restructuring 762 10,589 Employee-related 14,297 21,339 Professional services 9,726 8,589 Other 444 707 $ 58,982 $ 67,264

Collaboration Agreements (Table

Collaboration Agreements (Tables)	6 Months Ended
	Jun. 30, 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 ongoing costs related to the development of SAGE-217 products and SAGE-324 products, as reflected in our condensed consolidated statement of operations and comprehensive loss: Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 (in thousands) (in thousands) Collaboration revenue - related party $ 7,420 $ — $ 13,633 $ — Cost of revenues 1,294 — 2,495 — Research and development expenses 4,943 27,679 11,974 49,851 Selling, general and administrative expenses 13,072 28,755 26,055 47,718 The revenue, cost and expense categories in the table below reflect the following reimbursement amounts to (from) Biogen to account for the sharing of economics under the Biogen Collaboration Agreement: Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 (in thousands) (in thousands) Collaboration revenue - related party $ ( 7,420 ) $ — $ ( 13,633 ) $ — Cost of revenues ( 566 ) — ( 1,128 ) — Research and development expenses ( 3,325 ) ( 22,418 ) ( 8,982 ) ( 39,700 ) Selling, general and administrative expenses 1,019 7,476 3,325 10,510

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 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 1,277,080 $ 23.50 Vested ( 80,039 ) $ 44.21 Forfeited ( 172,516 ) $ 32.00 Outstanding as of June 30, 2024 4,112,919 $ 30.83
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 2,162,855 $ 21.79 Exercised ( 10,062 ) $ 7.69 Forfeited ( 3,243,941 ) $ 85.93 Expired ( 20,564 ) $ 8.92 Outstanding as of June 30, 2024 7,006,329 $ 54.99 5.78 $ — Exercisable as of June 30, 2024 4,278,083 $ 66.73 4.61 $ —
Summary of Stock-Based Compensation Expense Recognized	The following table summarizes stock-based compensation expense recognized during the six months ended June 30, 2024 and 2023: Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 (in thousands) Research and development $ 6,118 $ 4,496 $ 11,084 $ 13,269 Selling, general and administrative 11,049 7,197 19,781 18,462 $ 17,167 $ 11,693 $ 30,865 $ 31,731
Summary of Stock-Based Compensation Expense by Award Type	The following table summarizes stock-based compensation expense by award type recognized during the six months ended June 30, 2024 and 2023: Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 (in thousands) Stock options $ 7,724 $ 9,663 $ 15,175 $ 19,678 Restricted stock units 9,223 1,618 14,942 11,171 Employee stock purchase plan 220 412 748 882 $ 17,167 $ 11,693 $ 30,865 $ 31,731

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	6 Months Ended
	Jun. 30, 2024
Earnings Per Share [Abstract]
Summary of Basic and Diluted Net Loss Per Share	The following table shows the calculation of basic and diluted net loss per share for the six months ended June 30, 2024 and 2023: Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 Basic net loss per share: Numerator: Net loss (in thousands) $ ( 102,854 ) $ ( 160,325 ) $ ( 211,337 ) $ ( 307,153 ) Denominator: Weighted average common stock outstanding 60,538,319 59,769,640 60,337,258 59,722,147 Net loss per share - basic and diluted $ ( 1.70 ) $ ( 2.68 ) $ ( 3.50 ) $ ( 5.14 )
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 six months ended June 30, 2024 and 2023: Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 Stock options 6,551,329 7,851,925 6,551,329 7,851,925 Restricted stock units 2,343,027 445,421 2,343,027 445,421 Employee stock purchase plan 155,484 87,938 155,484 87,938 9,049,840 8,385,284 9,049,840 8,385,284

Restructuring (Tables)

Restructuring (Tables)	6 Months Ended
	Jun. 30, 2024
Restructuring and Related Activities [Abstract]
Schedule of Restructuring Accrual	The following table summarizes activity related to the restructuring accrual during the six months ended June 30, 2024: Restructuring Accrual (in thousands) Balance as of December 31, 2023 $ 10,589 Restructuring expenses incurred ( 597 ) Cash paid ( 9,230 ) Non-cash activity — Balance as of June 30, 2024 $ 762

Nature of the Business - Additi

Nature of the Business - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Jun. 30, 2024	Dec. 31, 2023
Nature Of Business [Line Items]
Accumulated deficit		$ 2,780,996	$ 2,569,659
Net income from up-front	$ 606,100
Redeemable Convertible Preferred Stock [Member] | Convertible Notes [Member] | Initial Public Offering [Member]
Nature Of Business [Line Items]
Accumulated deficit		$ 2,800,000

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2024
Summary Of Significant Accounting Policies [Line Items]
Incremental costs incurred expected amortization period of asset	true

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Company's Cash Equivalents and Marketable Securities (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	$ 98,874	$ 68,547
Total marketable securities	546,892	682,192
Total cash equivalents and marketable securities	645,766	750,739
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	93,902	59,852
Total cash equivalents and marketable securities	93,902	59,852
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	4,972	8,695
Total marketable securities	546,892	682,192
Total cash equivalents and marketable securities	551,864	690,887
Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	93,902	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	93,902	59,852
International Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	109,490	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	109,490	97,675
U.S. Government Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents		8,695
Total marketable securities	84,508	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		8,695
Total marketable securities	84,508	166,925
U.S. Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	205,394	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	205,394	210,198
U.S. Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	4,972
Total marketable securities	67,154	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	4,972
Total marketable securities	67,154	23,370
International Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	45,109	46,900
International Commercial Paper [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	45,109	46,900
U.S. Certificates of Deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	2,203	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	2,203	8,830
U.S. Municipal Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	33,034	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	$ 33,034	$ 128,294

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	Jun. 30, 2024	Jun. 30, 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	Jun. 30, 2024	Dec. 31, 2023
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 547,583	$ 683,006
Gross Unrealized Gains	25	437
Gross Unrealized Losses	(716)	(1,251)
Fair Value	546,892	682,192
U.S. Government Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	84,623	167,165
Gross Unrealized Gains	0	107
Gross Unrealized Losses	(115)	(347)
Fair Value	84,508	166,925
U.S. Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	205,746	210,491
Gross Unrealized Gains	6	191
Gross Unrealized Losses	(358)	(484)
Fair Value	205,394	210,198
International Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	109,641	97,698
Gross Unrealized Gains	15	99
Gross Unrealized Losses	(166)	(122)
Fair Value	109,490	97,675
U.S. Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	67,152	23,360
Gross Unrealized Gains	3	11
Gross Unrealized Losses	(1)	(1)
Fair Value	67,154	23,370
International Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	45,109	46,935
Gross Unrealized Gains	1	3
Gross Unrealized Losses	(1)	(38)
Fair Value	45,109	46,900
U.S. Certificates of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,203	8,830
Fair Value	2,203	8,830
U.S. Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	33,109	128,527
Gross Unrealized Gains		26
Gross Unrealized Losses	(75)	(259)
Fair Value	$ 33,034	$ 128,294

Investments - Summary of Fair V

Investments - Summary of Fair Value And Unrealized Losses of Marketable Securities In Loss Position (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	$ 322,255	$ 343,373
Less than 12 months, Unrealized Losses	(432)	(611)
Greater than 12 months, Fair Value	101,647	123,121
Greater than 12 months, Unrealized Losses	(284)	(640)
Fair Value	423,902	466,494
Unrealized Losses	(716)	(1,251)
U.S. Government Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	46,179	52,521
Less than 12 months, Unrealized Losses	(44)	(96)
Greater than 12 months, Fair Value	33,425	41,911
Greater than 12 months, Unrealized Losses	(71)	(251)
Fair Value	79,604	94,432
Unrealized Losses	(115)	(347)
U.S. Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	165,291	111,901
Less than 12 months, Unrealized Losses	(246)	(246)
Greater than 12 months, Fair Value	30,021	43,851
Greater than 12 months, Unrealized Losses	(112)	(238)
Fair Value	195,312	155,752
Unrealized Losses	(358)	(484)
International Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	79,172	43,708
Less than 12 months, Unrealized Losses	(109)	(87)
Greater than 12 months, Fair Value	19,985	6,014
Greater than 12 months, Unrealized Losses	(57)	(35)
Fair Value	99,157	49,722
Unrealized Losses	(166)	(122)
U.S. Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	12,887	7,848
Less than 12 months, Unrealized Losses	(1)	(1)
Fair Value	12,887	7,848
Unrealized Losses	(1)	(1)
International Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	3,908	37,300
Less than 12 months, Unrealized Losses	(1)	(38)
Fair Value	3,908	37,300
Unrealized Losses	(1)	(38)
U.S. Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	14,818	90,095
Less than 12 months, Unrealized Losses	(31)	(143)
Greater than 12 months, Fair Value	18,216	31,345
Greater than 12 months, Unrealized Losses	(44)	(116)
Fair Value	33,034	121,440
Unrealized Losses	$ (75)	$ (259)

Investments - Additional Inform

Investments - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Debt Securities, Available-for-Sale [Line Items]
Accrued Interest Receivable Written Off	$ 0	$ 0	$ 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	43,400,000		$ 43,400,000		$ 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	$ 3,800,000		$ 3,800,000		$ 4,200,000

Accrued Expenses - Summary of A

Accrued Expenses - Summary of Accrued Expenses (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Payables and Accruals [Abstract]
Accrued research and development costs	$ 33,753	$ 26,040
Restructuring	762	10,589
Employee-related	14,297	21,339
Professional services	9,726	8,589
Other	444	707
Total accrued expenses	$ 58,982	$ 67,264

Commitments and Contingencies -

Commitments and Contingencies - Operating Leases - Additional Information (Detail)	1 Months Ended	6 Months Ended
	Jan. 31, 2024 USD ($) ft²	Jun. 30, 2024 USD ($) ft²	Dec. 31, 2023 USD ($)
Commitments And Contingencies [Line Items]
Operating lease option to extend		true
Operating lease renewal term		5 years
Operating lease, right-of-use asset		$ 1,220,000	$ 4,458,000
Lease Agreements [Member]
Commitments And Contingencies [Line Items]
Office space rent under operating lease | ft²	30,567
Lease expire date	Aug. 31, 2024
Operating lease option to extend		The Company has the option to extend the New Lease one time for an additional five-year period
Expected commencement lease date	Sep. 01, 2024
Operating lease, right-of-use asset		$ 0
Operating lease, liability		$ 0
Initial term	66 months
Monthly base rent for first year	$ 224,158
Monthly base rent increase percentage	3%
Operating lease option to extend additional period	5 years
Letter of Credit [Member] | Lease Agreements [Member]
Commitments And Contingencies [Line Items]
Security deposit	$ 1,400,000
Security deposit amount reduced for third anniversary	1,200,000
Operating Lease One [Member]
Commitments And Contingencies [Line Items]
Office space rent under operating lease | ft²		63,017
Lease expire date		Aug. 31, 2024
Operating Lease Two [Member]
Commitments And Contingencies [Line Items]
Office space rent under operating lease | ft²		40,419
Lease expire date		Aug. 31, 2024
Operating Lease Three [Member]
Commitments And Contingencies [Line Items]
Office space rent under operating lease | ft²		15,525
Lease expire date		Nov. 30, 2024
Maximum [Member]
Commitments And Contingencies [Line Items]
Operating lease remaining lease terms		1 year
Maximum [Member] | Lease Agreements [Member]
Commitments And Contingencies [Line Items]
Construction allowance.	$ 3,400,000

Commitments and Contingencies_2

Commitments and Contingencies - CyDex License Agreement - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended		109 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024
Commitments And Contingencies [Line Items]
Research and development expense	$ 62,564,000	$ 97,161,000	$ 134,297,000	$ 189,987,000
CyDex License Agreement [Member]
Commitments And Contingencies [Line Items]
Research and development expense					$ 1,000,000
CyDex License Agreement [Member] | First and Second Clinical Development Milestones [Member] | Brexanolone [Member] | Maximum [Member]
Commitments And Contingencies [Line Items]
Expected milestone payments	800,000		800,000		800,000
CyDex License Agreement [Member] | First and Second Regulatory Milestones [Member] | Brexanolone [Member] | Maximum [Member]
Commitments And Contingencies [Line Items]
Expected milestone payments	3,800,000		3,800,000		3,800,000
CyDex License Agreement [Member] | Third and Fourth Clinical Development Milestones [Member] | Brexanolone [Member] | Maximum [Member]
Commitments And Contingencies [Line Items]
Expected milestone payments	1,300,000		1,300,000		1,300,000
CyDex License Agreement [Member] | Third and Fourth Regulatory Milestones [Member] | Brexanolone [Member] | Maximum [Member]
Commitments And Contingencies [Line Items]
Expected milestone payments	8,500,000		8,500,000		8,500,000
CyDex License Agreement [Member] | Clinical Development [Member] | SAGE-689 [Member] | Maximum [Member]
Commitments And Contingencies [Line Items]
Expected milestone payments	800,000		800,000		800,000
CyDex License Agreement [Member] | Regulatory Milestones [Member] | Brexanolone [Member]
Commitments And Contingencies [Line Items]
Milestone payments related to intangible assets	0	$ 0	0	$ 0
CyDex License Agreement [Member] | Regulatory Milestones [Member] | SAGE-689 [Member] | Maximum [Member]
Commitments And Contingencies [Line Items]
Expected milestone payments	1,800,000		1,800,000		1,800,000
CyDex License Agreement [Member] | Clinical Development and Regulatory Milestones [Member]
Commitments And Contingencies [Line Items]
Research and development expense related to milestone expense					3,600,000
Milestone payments					3,600,000
Intangible asset related to milestone	$ 3,000,000		$ 3,000,000		$ 3,000,000

Commitments and Contingencies_3

Commitments and Contingencies - University of California License Agreements - Additional Information (Detail) - University of California License Agreements [Member] - USD ($)		1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended	109 Months Ended
	Dec. 31, 2015	Jun. 30, 2015	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2015	Jun. 30, 2024
Commitments And Contingencies [Line Items]
Upfront payment		$ 50,000
Annual license maintenance fee							$ 15,000
Milestone payments			$ 0	$ 0	$ 0	$ 0
After The Effective Date [Member]
Commitments And Contingencies [Line Items]
Licenses Expiration period, maximum	27 years
After The First Sale [Member]
Commitments And Contingencies [Line Items]
Licenses Expiration period, maximum	15 years
Clinical Development [Member]
Commitments And Contingencies [Line Items]
Milestone payments	$ 100,000
Milestone outstanding	$ 0
Clinical Development [Member] | Maximum [Member]
Commitments And Contingencies [Line Items]
Percentage of net sales paid as royalties	1%
Regulatory Milestones [Member] | Maximum [Member]
Commitments And Contingencies [Line Items]
Expected milestone payments		700,000
Sales Milestones [Member] | Maximum [Member]
Commitments And Contingencies [Line Items]
Expected milestone payments		$ 2,000,000
Regulatory and Sales Milestones [Member]
Commitments And Contingencies [Line Items]
Research and development expense related to milestone expense								$ 300,000
Milestone payments								300,000
Intangible asset related to milestone			$ 500,000		$ 500,000			500,000
Milestone payments related to intangible assets								$ 500,000

Collaboration Agreements - Addi

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

1 Months Ended

3 Months Ended

6 Months Ended

12 Months Ended

Nov. 30, 2020

Jun. 30, 2018

Jan. 31, 2024

Jun. 30, 2024

Mar. 31, 2024

Dec. 31, 2023

Jun. 30, 2023

Mar. 31, 2023

Dec. 31, 2022

Jun. 30, 2018

Jun. 30, 2024

Jun. 30, 2023

Dec. 31, 2023

Dec. 31, 2020

Jun. 12, 2018

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Revenue

$ 8,654,000

$ 2,474,000

$ 16,556,000

$ 5,768,000

Collaboration receivable - related party

9,943,000

$ 83,009,000

9,943,000

$ 83,009,000

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

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Revenue

600,000

14,000

600,000

14,000

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

Collaborative Arrangements And Noncollaborative Arrangement Transactions [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] | Maximum [Member]

Collaborative Arrangements And Noncollaborative Arrangement Transactions [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 Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Future milestone payments

70,000,000

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

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Future milestone payments

30,000,000

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

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Future milestone payments

$ 385,000,000

Biogen Collaboration Agreement [Member]

Collaborative Arrangements And Noncollaborative Arrangement Transactions [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, net of issuance costs ,Shares

6,241,473

Purchase price

$ 650,000,000

Net reimbursement

(7,420,000)

(13,633,000)

8,000,000

Milestone achieved

75,000,000

Payments to related parties

0

0

Proceeds from related parties

$ 93,100,000

93,100,000

$ 27,800,000

$ 27,800,000

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

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaboration receivable - related party

9,900,000

83,000,000

9,900,000

$ 83,000,000

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

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Revenue

$ 0

75,000,000

$ 0

$ 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 Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Milestone achieved

$ 75,000,000

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

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Additional milestone payment receivable

$ 1,600,000,000

Biogen Collaboration Agreement [Member] | SAGE-217 [Member] | Maximum [Member] | First Commercial Sale of Zurzuvae for Treatment of MDD [Member]

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Future milestone payments

$ 150,000,000

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

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Future milestone payments

75,000,000

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

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Future milestone payments

300,000,000

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

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Future milestone payments

475,000,000

Biogen Collaboration Agreement [Member] | SAGE-324 [Member] | Treatment of Essential Tremor [Member]

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Future milestone payments

150,000,000

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

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Future milestone payments

300,000,000

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

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Future milestone payments

$ 520,000,000

Biogen Stock Purchase Agreement [Member]

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Upfront payment

875,000,000

Purchase price

650,000,000

Transaction price, total

1,100,000,000

Premium amount on equity investment

$ 232,500,000

Price per share

$ 104.14

Biogen stock purchase agreement, description

terminate on the earliest of (i) a specified regulatory milestone under the Biogen Collaboration Agreement, (ii) the date one year following the termination of the Biogen Collaboration Agreement and (iii) the seventh anniversary of the Effective Date.

Stock issued

$ 417,500,000

Collaboration Agreements - Summ

Collaboration Agreements - Summary of Activity and Reimbursement Amounts Related to Collaboration Agreement (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023	Dec. 31, 2020
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue	$ 8,654	$ 2,474	$ 16,556	$ 5,768
Research and development expenses	62,564	97,161	134,297	189,987
Selling, general and administrative expenses	55,983	75,565	108,556	141,273
Collaboration Revenue - Related Party [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue	7,420		13,633
Biogen Collaboration Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue						$ 1,100,000
Cost of revenues	1,294		2,495
Research and development expenses	4,943	27,679	11,974	49,851
Selling, general and administrative expenses	13,072	28,755	26,055	47,718
Reimbursement amounts to (from) collaboration [Abstract]
Collaboration revenue - related party	(7,420)		(13,633)		$ 8,000
Cost of revenues	(566)		(1,128)
Selling, general and administrative expenses	1,019	7,476	3,325	10,510
Biogen Collaboration Agreement [Member] | Research and Development [Member]
Reimbursement amounts to (from) collaboration [Abstract]
Research and development expenses	(3,325)	$ (22,418)	(8,982)	$ (39,700)
Biogen Collaboration Agreement [Member] | Collaboration Revenue - Related Party [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue	$ 7,420		$ 13,633

Common Stock - Additional Infor

Common Stock - Additional Information (Details) - USD ($)		3 Months Ended	6 Months Ended		12 Months Ended
	Nov. 07, 2023	Jun. 30, 2024	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Subsidiary or Equity Method Investee [Line Items]
Common stock, shares authorized		120,000,000	120,000,000		120,000,000
Common stock, par value		$ 0.0001	$ 0.0001		$ 0.0001
Voting rights			Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders.
Dividends declared			$ 0		$ 0
Purchase of treasury stock, Shares			3,033
Total cost of shares held in treasury		$ 400,000	$ 400,000		$ 400,000
Sale of stock, commissions, underwriting discounts, and offering costs			$ 117,000	$ 0
Sales Agreement [Member]
Subsidiary or Equity Method Investee [Line Items]
Aggregate offering price of common stock shares issued	$ 250,000,000
Sale of stock, number of shares issued in transaction (in shares)		700,000
Price per share		$ 11.9	$ 11.9
Gross proceeds		$ 8,300,000
Sale of stock, commissions, underwriting discounts, and offering costs		$ 300,000
Shares remained available for issuance		241,700,000	241,700,000
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)				3 Months Ended			6 Months Ended
	Jun. 10, 2024 shares	Feb. 21, 2024 $ / shares shares	Jun. 15, 2023 shares	Jun. 30, 2024 USD ($) $ / shares shares	Jun. 30, 2023 USD ($) shares	Mar. 31, 2023 USD ($) Milestone	Jun. 30, 2024 USD ($) Milestone $ / shares shares	Jun. 30, 2023 USD ($) Milestone $ / shares shares	Apr. 16, 2024 shares	Jan. 23, 2024 $ / shares	Dec. 31, 2023 $ / shares shares	Jun. 16, 2022 shares	Sep. 20, 2018 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation granted under plan vested period							4 years
Share based compensation, vest period							1 year
Share based compensation, term of plan							10 years
Stock-based compensation expense tied to total stockholder return | $							$ 30,865,000	$ 31,731,000
Stock-based compensation expense | $				$ 17,167,000	$ 11,693,000		30,865,000	$ 31,731,000
Total unrecognized stock-based compensation expense | $				$ 40,300,000			$ 40,300,000
Weighted average grant date fair value per share | $ / shares							$ 14.69	$ 30.41
Time Based Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units granted				24,941	0		882,025	330,617
Restricted stock units vested				10,096	14,144		80,039	28,577
Fair value of restricted stock units vested | $				$ 100,000	$ 700,000		$ 1,700,000	$ 1,300,000
Outstanding and unvested restricted stock units				2,343,027			2,343,027
Total unrecognized stock-based compensation expense | $				$ 28,800,000			$ 28,800,000
Performance Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense tied to total stockholder return | $				$ 400,000	$ 21,000		$ 800,000	$ 300,000
Restricted stock units granted				0	39,603		395,055	862,321
Fair value of restricted stock units vested | $				$ 0	$ 0		$ 0
Stock-based compensation expense | $				$ 2,800,000
Outstanding and unvested restricted stock units				1,769,892			1,769,892
Total unrecognized stock-based compensation expense | $				$ 66,500,000			$ 66,500,000
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted							2,162,855
Stock options exercise price per share | $ / shares				$ 54.99			$ 54.99				$ 76.02
Total number of shares outstanding				7,006,329			7,006,329				8,118,041
Stock-based compensation expense | $				$ 7,724,000	9,663,000		$ 15,175,000	$ 19,678,000
Weighted average period of unrecognized compensation costs							2 years 7 months 28 days
Intrinsic value of options exercised | $							$ 100,000	1,900,000
Exercise price per share of the replacement options | $ / shares				$ 66.73			$ 66.73
Options elected to be cancelled							3,243,941
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
Total unrecognized stock-based compensation expense | $				$ 24,900,000			$ 24,900,000
Number of shares outstanding and unvested stock options				455,000			455,000
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units granted							1,277,080
Stock-based compensation expense | $				$ 9,223,000	$ 1,618,000		$ 14,942,000	$ 11,171,000
Outstanding and unvested restricted stock units				4,112,919			4,112,919				3,088,394
Restricted Stock Units Vest One Year Anniversary [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units vesting percentage							25%
2011 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted							0
Total number of shares outstanding				0			0
2014 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 | $						$ 5,500,000
Stock-based compensation expense | $						$ 8,500,000
Regulatory development Milestone achieved | Milestone						1
2014 Plan [Member] | Performance-Based Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Regulatory development Milestone achieved | Milestone							0	0
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]
Additional number of shares reserved for issuance			500,000
Total number of shares reserved for issuance			1,082,000									300,000
Common stock available for issuance under stock option plan				574,678			574,678
Option Exchange Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted		1,483,113
Share based compensation granted under plan vested period		18 months
Share based compensation, term of plan		7 years
Exercise price per share of the replacement options | $ / shares		$ 22.2
Options to purchase		3,079,608
Additional stock-based compensation expense | $							$ 1,700,000
Replacement options vesting period							18 months
Option Exchange Program [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options exercise price per share | $ / shares										$ 35
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				5,480,598			5,480,598
2024 Plan, 2014 Plan and 2016 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total number of shares outstanding				11,119,248			11,119,248

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Activity Relating to Restricted Stock Units (Detail) - Restricted Stock Units [Member]	6 Months Ended
	Jun. 30, 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	1,277,080
Vested, Shares | shares	(80,039)
Forfeited, Shares | shares	(172,516)
Outstanding, Shares at ending balance | shares	4,112,919
Outstanding, Weighted Average Grant Date Fair Value at beginning balance | $ / shares	$ 34.27
Granted, Weighted Average Grant Date Fair Value | $ / shares	23.5
Vested, Weighted Average Grant Date Fair Value | $ / shares	44.21
Forfeited, Weighted Average Grant Date Fair Value | $ / shares	32
Outstanding, Weighted Average Grant Date Fair Value at ending balance | $ / shares	$ 30.83

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Activity Relating to Time Based and Performance Based Stock Options (Detail) - Stock Options [Member] $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2024 $ / shares shares	Dec. 31, 2023 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, Outstanding Shares | shares	8,118,041
Granted, Shares | shares	2,162,855
Exercised, Shares | shares	(10,062)
Forfeited, Shares | shares	(3,243,941)
Expired, Shares | shares	(20,564)
Ending balance, Outstanding Shares | shares	7,006,329	8,118,041
Exercisable, Shares | shares	4,278,083
Beginning balance, Outstanding Weighted Average Exercise Price | $ / shares	$ 76.02
Granted, Weighted Average Exercise Price | $ / shares	21.79
Exercised, Weighted Average Exercise Price | $ / shares	7.69
Forfeited, Weighted Average Exercise Price | $ / shares	85.93
Expired, Weighted Average Exercise Price | $ / shares	8.92
Ending balance, Outstanding Weighted Average Exercise Price | $ / shares	54.99	$ 76.02
Exercisable, Weighted Average Exercise Price | $ / shares	$ 66.73
Outstanding, Weighted Average Remaining Life	5 years 9 months 10 days	5 years 7 months 28 days
Exercisable, Weighted Average Remaining Life	4 years 7 months 9 days
Outstanding, Aggregate Intrinsic Value | $		$ 475

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of Stock-Based Compensation Expense Recognized (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	$ 17,167	$ 11,693	$ 30,865	$ 31,731
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	6,118	4,496	11,084	13,269
Selling, General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	$ 11,049	$ 7,197	$ 19,781	$ 18,462

Stock-Based Compensation - Su_4

Stock-Based Compensation - Summary of Stock-Based Compensation Expense by Award Type (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	$ 17,167	$ 11,693	$ 30,865	$ 31,731
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	7,724	9,663	15,175	19,678
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	9,223	1,618	14,942	11,171
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	$ 220	$ 412	$ 748	$ 882

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	3 Months Ended				6 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023
Numerator:
Net loss	$ (102,854)	$ (108,483)	$ (160,325)	$ (146,828)	$ (211,337)	$ (307,153)
Denominator:
Weighted average common stock outstanding - basic	60,538,319		59,769,640		60,337,258	59,722,147
Weighted average common stock outstanding - diluted	60,538,319		59,769,640		60,337,258	59,722,147
Net loss per share - basic	$ (1.7)		$ (2.68)		$ (3.5)	$ (5.14)
Net loss per share - diluted	$ (1.7)		$ (2.68)		$ (3.5)	$ (5.14)

Net Loss Per Share - Summary _2

Net Loss Per Share - Summary of Potential Dilutive Securities Outstanding (Detail) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents	9,049,840	8,385,284	9,049,840	8,385,284
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents	6,551,329	7,851,925	6,551,329	7,851,925
Restricted Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents	2,343,027	445,421	2,343,027	445,421
Employee Stock Purchase Plan [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents	155,484	87,938	155,484	87,938

Restructuring - Additional Info

Restructuring - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	6 Months Ended
	Aug. 31, 2023	Jun. 30, 2024
Restructuring Cost and Reserve [Line Items]
Percentage of workforce eliminated	40%
Restructuring charges expected to be incurred		$ 32.8

Restructuring - Schedule of Res

Restructuring - Schedule of Restructuring Accrual (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2024 USD ($)
Restructuring Reserve [Roll Forward]
Restructuring accrual, Balance as of December 31, 2023	$ 10,589
Restructuring expenses incurred	(597)
Cash paid	(9,230)
Non-cash activity	0
Restructuring accrual, Balance as of June 30, 2024	$ 762