Sage Therapeutics (SAGE) 10-K 16 Feb 23 2022 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2022	Feb. 08, 2023	Jun. 30, 2022
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY
Trading Symbol	SAGE
Entity Registrant Name	Sage Therapeutics, Inc.
Entity Central Index Key	0001597553
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
ICFR Auditor Attestation Flag	true
Entity Common Stock, Shares Outstanding		59,717,608
Entity Public Float			$ 1,685,744,591
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Security Exchange Name	NASDAQ
Entity File Number	001-36544
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	27-4486580
Entity Address, Address Line One	215 First Street
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02142
City Area Code	617
Local Phone Number	299-8380
Document Annual Report	true
Document Transition Report	false
Auditor Name	PricewaterhouseCoopers LLP
Auditor Firm ID	238
Auditor Location	Boston, Massachusetts
Documents Incorporated by Reference	Part III of this Annual Report on Form 10-K incorporates by reference certain information from the registrant’s definitive Proxy Statement for its 2023 annual meeting of shareholders, which the registrant intends to file pursuant to Regulation 14A with the Securities and Exchange Commission not later than 120 days after the registrant’s fiscal year end of December 31, 2022 . Except with respect to information specifically incorporated by reference in this Form 10-K, the Proxy Statement is not deemed to be filed as part of this Form 10-K.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 162,700	$ 294,233
Marketable securities	1,109,794	1,448,063
Prepaid expenses and other current assets	50,826	39,841
Collaboration receivable - related party	13,660	18,506
Total current assets	1,336,980	1,800,643
Property and equipment, net	2,898	3,016
Restricted cash	1,269	1,269
Right-of-use operating asset	10,532	16,109
Other long-term assets	4,770	4,251
Total assets	1,356,449	1,825,288
Current liabilities:
Accounts payable	18,950	10,450
Accrued expenses	72,666	67,275
Operating lease liability, current portion	7,643	7,468
Total current liabilities	99,259	85,193
Operating lease liability, net of current portion	4,491	10,964
Other liabilities	100	100
Total liabilities	103,850	96,257
Commitments and contingencies (Note 5)
Stockholders’ equity:
Preferred stock, $0.0001 par value per share; 5,000,000 shares authorized at December 31, 2022 and December 31, 2021; no shares issued or outstanding at December 31, 2022 and December 31, 2021
Common stock, $0.0001 par value per share; 120,000,000 shares authorized at December 31, 2022 and December 31, 2021; 59,512,158 and 58,940,083 shares issued at December 31, 2022 and December 31, 2021; 59,509,125 and 58,937,050 shares outstanding at December 31, 2022 and December 31, 2021	6	6
Treasury stock, at cost, 3,033 shares at December 31, 2022 and December 31, 2021	(400)	(400)
Additional paid-in capital	3,291,369	3,227,471
Accumulated deficit	(2,028,170)	(1,495,386)
Accumulated other comprehensive loss	(10,206)	(2,660)
Total stockholders’ equity	1,252,599	1,729,031
Total liabilities and stockholders’ equity	$ 1,356,449	$ 1,825,288

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2022	Dec. 31, 2021
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	59,512,158	58,940,083
Common stock, shares outstanding	59,509,125	58,937,050
Treasury stock, shares	3,033	3,033

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Total revenue	$ 7,686	$ 6,308	$ 1,114,200
Operating costs and expenses:
Cost of goods sold	813	553	565
Research and development	326,163	283,166	292,714
Selling, general and administrative	227,699	183,498	196,952
Restructuring			27,743
Total operating costs and expenses	554,675	467,217	517,974
Income (loss) from operations	(546,989)	(460,909)	596,226
Interest income, net	14,190	2,883	9,597
Other income, net	15	134	250
Net income (loss)	$ (532,784)	$ (457,892)	$ 606,073
Net income (loss) per share—basic	$ (8.98)	$ (7.80)	$ 11.66
Net income (loss) per share—diluted	$ (8.98)	$ (7.80)	$ 11.43
Weighted average number of common shares outstanding—basic	59,306,094	58,670,230	51,983,188
Weighted average number of common shares outstanding—diluted	59,306,094	58,670,230	53,003,115
Comprehensive income (loss):
Net income (loss)	$ (532,784)	$ (457,892)	$ 606,073
Other comprehensive items:
Unrealized loss on marketable securities	(7,546)	(3,075)	(880)
Total other comprehensive loss	(7,546)	(3,075)	(880)
Total comprehensive income (loss)	(540,330)	(460,967)	605,193
Product Revenue [Member]
Total revenue	$ 7,686	$ 6,308	6,700
Collaboration Revenue - Related Party [Member]
Total revenue			$ 1,107,500

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Gain (Loss) [Member]	Accumulated Deficit [Member]
Balances at Dec. 31, 2019	$ 944,655	$ 5	$ (400)	$ 2,587,322	$ 1,295	$ (1,643,567)
Balances, Shares at Dec. 31, 2019		51,877,194	3,033
Issuance of common stock from exercise of stock options, Amount	5,082			5,082
Issuance of common stock from exercise of stock options, Shares		117,025
Issuance of common stock under the employee stock purchase plan	4,936			4,936
Issuance of common stock under the employee stock purchase plan, Shares		72,719
Issuance of common stock under the Stock Purchase Agreement - related party	417,500	$ 1		417,499
Issuance of common stock under the Stock Purchase Agreement - related party, Shares		6,241,473
Stock-based compensation expense	94,968			94,968
Change in unrealized loss on available-for-sale securities	(880)				(880)
Net income (loss)	606,073					606,073
Balances at Dec. 31, 2020	2,072,334	$ 6	$ (400)	3,109,807	415	(1,037,494)
Balances, Shares at Dec. 31, 2020		58,308,411	3,033
Issuance of common stock from exercise of stock options, Amount	12,397			12,397
Issuance of common stock from exercise of stock options, Shares		307,378
Issuance of common stock under the employee stock purchase plan	2,761			2,761
Issuance of common stock under the employee stock purchase plan, Shares		46,759
Stock-based compensation expense	103,891			103,891
Vesting of restricted stock units, net of employee tax obligations	(1,385)			(1,385)
Vesting of restricted stock units, net of employee tax obligations, Shares		274,502
Change in unrealized loss on available-for-sale securities	(3,075)				(3,075)
Net income (loss)	(457,892)					(457,892)
Balances at Dec. 31, 2021	1,729,031	$ 6	$ (400)	3,227,471	(2,660)	(1,495,386)
Balances, Shares at Dec. 31, 2021		58,937,050	3,033
Issuance of common stock from exercise of stock options, Amount	1,037			1,037
Issuance of common stock from exercise of stock options, Shares		150,045
Issuance of common stock under the employee stock purchase plan	2,346			2,346
Issuance of common stock under the employee stock purchase plan, Shares		57,239
Stock-based compensation expense	60,558			60,558
Vesting of restricted stock units, net of employee tax obligations	(43)			(43)
Vesting of restricted stock units, net of employee tax obligations, Shares		364,791
Change in unrealized loss on available-for-sale securities	(7,546)				(7,546)
Net income (loss)	(532,784)					(532,784)
Balances at Dec. 31, 2022	$ 1,252,599	$ 6	$ (400)	$ 3,291,369	$ (10,206)	$ (2,028,170)
Balances, Shares at Dec. 31, 2022		59,509,125	3,033

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities
Net income (loss)	$ (532,784)	$ (457,892)	$ 606,073
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Stock-based compensation expense	61,602	104,629	95,994
Premium on marketable securities	(1,500)	(23,641)	(1,736)
Amortization of premium (discount) on marketable securities	5,853	13,046	1,048
Depreciation expense	1,122	4,182	2,630
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(10,985)	(17,020)	3,879
Collaboration receivable - related party	4,846	(18,506)
Other long-term assets	(519)	(910)	452
Right-of-use operating asset	5,577	5,221	6,397
Operating lease liabilities, current	175	206	36
Operating lease liabilities, non-current	(6,473)	(5,944)	(6,825)
Accounts payable	8,433	6,689	(11,511)
Accrued expenses and other liabilities	4,617	11,758	(32,157)
Net cash provided by (used in) operating activities	(460,036)	(378,182)	664,280
Cash flows from investing activities
Proceeds from sales and maturities of marketable securities	1,207,407	988,075	901,749
Purchases of marketable securities	(881,037)	(1,990,151)	(458,720)
Purchases of property and equipment	(937)	(372)	(345)
Net cash provided by (used in) investing activities	325,433	(1,002,448)	442,684
Cash flows from financing activities
Proceeds from stock option exercises and employee stock purchase plan issuances	3,113	14,719	9,262
Payment of employee tax obligations related to vesting of restricted stock units	(43)	(1,385)
Proceeds from the sale of common stock under the Stock Purchase Agreement - related party			417,500
Net cash provided by financing activities	3,070	13,334	426,762
Net increase (decrease) in cash, cash equivalents and restricted cash	(131,533)	(1,367,296)	1,533,726
Cash, cash equivalents and restricted cash at beginning of period	295,502	1,662,798	129,072
Cash, cash equivalents and restricted cash at end of period	163,969	295,502	1,662,798
Supplemental disclosure of non-cash operating and investing activities
Purchases of property and equipment included in accounts payable	$ 137	70
Lease asset de-recognized upon lease cancellation		$ 3,733	$ 2,310

Nature of the Business

Nature of the Business	12 Months Ended
	Dec. 31, 2022
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 first product, ZULRESSO® (brexanolone) CIV injection, is approved in the U.S. as a treatment for postpartum depression (“PPD”) in adults. The Company launched ZULRESSO commercially in the U.S. in June 2019. The Company's submission of a new drug application (an "NDA") for its lead investigational product candidate, zuranolone, for the treatment of major depressive disorder (“MDD”) and PPD was accepted for filing and granted priority review by the U.S. Food and Drug Administration (“FDA”) in February 2023. The Company has a portfolio of other product candidates with a current focus on modulating two critical central nervous system (“CNS”) receptor systems, GABA and NMDA. The GABA receptor family, which is recognized as the major inhibitory neurotransmitter in the CNS, mediates downstream neurologic and bodily function via activation of GABA A receptors. The NMDA-type receptors of the glutamate receptor system are a major excitatory receptor system in the CNS. Dysfunction in these systems is implicated in a broad range of CNS disorders. The Company is currently targeting diseases and disorders of the brain with three key focus areas: depression, neurology and neuropsychiatry. 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 biotechnology and pharmaceutical industries, 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 impact of the COVID-19 pandemic on its development activities, operations and financial condition. The product candidates developed by the Company require approvals from the FDA or foreign regulatory agencies prior to commercial sales. There can be no assurance that the current and future product candidates of the Company will receive, or that the Company’s current product, ZULRESSO, 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, including zuranolone, 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 related to the ongoing COVID-19 pandemic and other macroeconomic and geopolitical events, which collectively have caused and may continue to cause major disruptions to businesses and economies worldwide. The rapid spread of COVID-19 in the U.S. resulted in a significant reduction in patient demand for ZULRESSO and in the number of sites available to administer ZULRESSO at certain points during the pandemic. There have been and continue to be healthcare staffing shortages and other changes to the macroeconomic environment as downstream effects of the pandemic have continued. These factors have had a significant and sustained negative impact on the Company’s revenue from sales of ZULRESSO. While the Company has not experienced any other material disruptions to date as a result of the COVID-19 pandemic, any prolonged material disruptions to the work of the Company’s employees, suppliers, contract manufacturers, or vendors could negatively impact the Company’s activities, availability of supplies, or operating results. In addition, while the Company has seen slower patient recruitment in certain clinical trials due to the COVID-19 pandemic and its downstream effects, and has experienced some challenges in qualifying and activating clinical trial sites, including due to capacity and resource constraints and employee attrition at our vendors and at sites, the Company has not experienced other significant impacts to the Company’s development activities as a result of the COVID-19 pandemic. Any material disruption to the Company’s development activities may cause delays, increase the Company’s costs and impact the Company’s operating results. In addition, the COVID-19 pandemic initially caused major volatility in capital markets and a significant global economic downturn, and the Company’s ability to access the capital markets in the future could be negatively impacted if there are long-term negative effects of the COVID-19 pandemic on the macroeconomic environment or capital markets. Moreover, U.S. and global financial markets have experienced volatility and disruption due to other macroeconomic and geopolitical events such as rising inflation, the risk of a recession and the ongoing conflict between Russia and Ukraine. 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 MA Inc. (“BIMA”) and Biogen International GmbH (collectively with BIMA, “Biogen”) (the “Biogen Collaboration Agreement”). As of December 31, 2022, the Company had an accumulated deficit of $ 2.0 billion. From its inception through December 31, 2022, the Company has received aggregate net proceeds of $ 2.8 billion from the sales of redeemable convertible preferred stock prior to its initial public offering (“IPO”), the issuance of convertible notes, and the sales of common stock in its IPO in July 2014, in follow-on public offerings and to BIMA under a stock purchase agreement executed in connection with the Biogen Collaboration Agreement. The Company has also received $ 1.0 billion in upfront payments under its collaborations with Biogen and Shionogi & Co., Ltd. (“Shionogi”). Until such time, if ever, as the Company can generate substantial product revenue and/or collaboration revenue and achieve sustained profitability, the Company expects to finance its cash needs through a combination of equity offerings, debt financings, collaborations, strategic alliances, licensing arrangements and other sources of funding. If the Company is unable to raise additional funds through equity or debt financings or other sources of funding when needed, the Company may be required to delay, limit, reduce or terminate product development or future commercialization efforts or grant rights to develop and market products or product candidates that the Company would otherwise prefer to develop and market itself. The Company expects that, based on its current operating plans, the Company’s existing cash, cash equivalents and marketable securities will be sufficient to fund its currently planned operations for at least the next 12 months from the filing date of this Annual Report. At some point after that time, the Company anticipates it will require additional financing to fund its future operations. Even if the Company believes it has sufficient funds for its current or future operating plans, the Company may seek to raise additional capital if market conditions are favorable or in light of other strategic considerations.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies The following is a summary of significant accounting policies followed in the preparation of these consolidated financial statements. Basis of Presentation The accompanying consolidated financial statements include those of the Company and its subsidiaries after elimination of all intercompany accounts and transactions. The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the U.S. (“GAAP”). Principles of Consolidation The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. Intercompany accounts and transactions have been eliminated. Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. The full extent to which the COVID-19 pandemic and its downstream effects may directly or indirectly impact the Company’s business, results of operations and financial condition, including sales, expenses, reserves and allowances, manufacturing, clinical trials, research and development costs and employee-related amounts, will depend in large part on future developments, which cannot be predicted with confidence at this time, including: the scope, duration and severity of ongoing and future waves of the pandemic, including the impact of any variant strains of the COVID-19 virus; the extent of healthcare staffing shortages that have continued even as COVID-19 related restrictions have eased; the impact of the pandemic on the Company’s customers and vendors, including capacity and resource constraints; the impact of the downstream effects of the pandemic on business operations across the U.S.; and the scope and extent of any future actions or restrictive measures taken to contain or mitigate the impact of the pandemic . The Company has made estimates of the impact of the COVID-19 pandemic within its consolidated financial statements. Due to the evolving nature of the COVID-19 pandemic, its downstream effects, and their impacts, there may be changes to those estimates in future periods, and a ctual results could differ from those estimates. Cash Equivalents The Company considers all highly liquid investments with an original maturity of 90 days or less to be cash equivalents. As of December 31, 2022, cash equivalents were comprised of money market funds. As of December 31, 2021 , cash equivalents were comprised of money market funds, U.S. commercial paper and international commercial paper. Marketable Securities Marketable securities consist of investments with original maturities greater than 90 days. The Company has classified its investments with maturities beyond one year as short-term, based on their highly liquid nature and because such marketable securities represent the investment of cash that is available for current operations. The Company considers its investment portfolio of marketable securities to be available-for-sale. Accordingly, these investments are recorded at fair value, which is based on quoted market prices. Unrealized gains and losses are reported as the accumulated other comprehensive items in stockholders’ equity. When the fair value is below the amortized cost of the asset, an estimate of expected credit losses is made. The credit-related impairment amount is recognized in net income (loss); the remaining impairment amount and unrealized gains are reported as a component of accumulated other comprehensive items in stockholders’ equity. Credit losses are recognized through the use of an allowance for credit losses account and subsequent improvements in expected credit losses are recognized as a reversal of an amount in the allowance for credit losses account. If the Company has the intent to sell the security or it is more likely than not that the Company will be required to sell the security prior to recovery of its amortized cost basis, then the allowance for the credit loss is written-off and the excess of the amortized cost basis of the asset over its fair value is recorded in the consolidated statements of operations and comprehensive income (loss). Regardless of the Company’s intent to sell a security, it performs additional analysis on all securities with unrealized losses to evaluate losses associated with the creditworthiness of the security. Credit losses are identified where the Company does not expect to receive cash flows sufficient to recover the amortized cost basis of a security. Accounts Receivable The Company’s trade accounts receivable consist of amounts due from specialty distributors, specialty pharmacies, and medically-supervised healthcare settings that have been certified under a Risk Evaluation and Mitigation Strategy (“REMS”) program in the U.S. related to sales of ZULRESSO and have standard payment terms that generally require payment within 30 to 90 days from the invoice date. The Company monitors the financial performance and creditworthiness of customers so that it can properly assess and respond to changes in their credit profiles. The Company makes judgments as to its ability to collect outstanding receivables and provides an allowance for bad debts against the trade account receivables, when appropriate. As of December 31, 2022 and 2021, trade accounts receivable were $ 1.5 million and $ 1.1 million, respectively, and are included in prepaid expenses and other current assets on the consolidated balance sheets. As of December 31, 2022 , the Company has not provided any allowance for bad debts against the trade accounts receivable. Inventory Prior to the initial date that regulatory approval is received for a product candidate of the Company, costs related to the production of inventory are recorded as research and development expense on the Company’s consolidated statements of operations and comprehensive income (loss) in the period incurred. In connection with the FDA approval of ZULRESSO in March 2019, the Company subsequently began capitalizing inventory manufactured or purchased after this date. Inventory is stated at the lower of cost or estimated net realizable value with cost determined on a first-in, first-out basis. Inventory costs include raw materials, third-party contract manufacturing, third-party packaging services, and freight. Raw and intermediate materials that may be utilized for either research and development or commercial purposes, after approval of the product by the FDA, are classified as inventory. Amounts in inventory that are used for research and development purposes are charged to research and development expense when the product enters the research and development process and can no longer be used for commercial purposes and, therefore, does not have an “alternative future use” as defined in authoritative guidance. The Company performs an assessment of the recoverability of capitalized inventory during each reporting period and, if needed, writes down any excess and obsolete inventory to its estimated net realizable value in the period it is identified. If they occur, such impairment charges are recorded as a component of cost of goods sold in the consolidated statements of operations and comprehensive income (loss). As of December 31, 2022 and 2021, inventory was $ 1.7 million and $ 1.4 million, respectively, and are included in prepaid expenses and other current assets on the consolidated balance sheets. Property and Equipment Property and equipment are recorded at cost and depreciated over their estimated useful lives using the straight-line method. Upon retirement or sale, the cost of assets disposed of and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is credited or charged to the Company's consolidated statements of operations and comprehensive income (loss). Repairs and maintenance costs are expensed as incurred. Leases The Company determines if an arrangement is a lease at contract inception. Operating lease assets represent the Company’s right to use an underlying asset for the lease term and operating lease liabilities represent the Company’s obligation to make payments arising from the lease. Operating lease assets and liabilities are recognized at the commencement date of the lease based upon the present value of lease payments over the lease term. When determining the lease term, the Company includes options to extend or terminate the lease when it is reasonably certain that the Company will exercise those options. The Company uses the Company’s incremental borrowing rate when the implicit interest rate is not readily determinable based upon the information available at the commencement date of the lease in determining the present value of the lease payments and the implicit interest rate when readily determinable. The lease payments used to determine the Company’s operating lease assets may include lease incentives, stated rent increases and escalation clauses linked to rates of inflation, when determinable, and are recognized in the Company’s operating lease assets in the Company’s consolidated balance sheets. In addition, the Company’s contracts may contain lease and non-lease components. The Company combines lease and non-lease components, which are accounted for together as lease components. The Company’s operating leases are reflected in the right-of-use operating asset; operating lease liability, current portion; and operating lease liability, net of current portion in the Company’s consolidated balance sheets. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. Short-term leases, defined as leases that have a lease term of 12 months or less at the commencement date, are not recorded on the Company’s consolidated balance sheets and are recognized in the consolidated statements of operations and comprehensive income (loss) on a straight-line basis over the term of the lease. Variable lease payments are the amounts owed by the Company to a lessor that are not fixed, such as reimbursement for common area maintenance and utilities costs for facility leases. Variable lease payments are expensed when incurred. Impairment of Long-Lived Assets Long-lived assets consist of property and equipment. Long-lived assets to be held and used are tested for recoverability whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends, and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long-lived asset group for recoverability, the Company compares forecasts of undiscounted cash flows expected to result from the use and eventual disposition of the long-lived asset group to its carrying value. The impairment loss would be based on the excess of the carrying value of the impaired asset over its fair value, determined based on discounted cash flows. To date, the Company has not recorded any impairment losses on long-lived assets. Cost of Goods Sold Cost of goods sold includes direct and indirect costs related to the manufacturing and distribution of ZULRESSO, including third-party manufacturing costs, packaging services, freight, third-party royalties payable on the Company’s net product revenue and amortization of intangible assets associated with ZULRESSO. Cost of goods sold may also include period costs related to certain inventory manufacturing services, inventory adjustment charges, as well as manufacturing variances. In connection with the FDA approval of ZULRESSO in March 2019, the Company subsequently began capitalizing inventory manufactured or purchased after this date. As a result, certain manufacturing costs associated with product shipments of ZULRESSO were expensed prior to FDA approval and, therefore, are not included in cost of goods sold during the years ended December 31, 2022 and 2021 . Research and Development Costs and Accruals Research and development expenses are comprised of costs incurred in performing research and development activities, including salaries and benefits, overhead costs, depreciation, contract services and other related costs. Research and development costs are expensed to operations as the related obligation is incurred. The Company has entered into various research and development contracts with research institutions and other companies both inside and outside of the U.S. These agreements are generally cancelable, and related costs are recorded as research and development expenses as incurred. The Company records accruals for estimated ongoing research and development costs. When billing terms under these contracts do not coincide with the timing of when the work is performed, the Company is required to make estimates of outstanding obligations to those third parties as of the end of the reporting period. Any accrual estimates are based on a number of factors, including the Company’s knowledge of the progress towards completion of the research and development activities, invoicing to date under the contracts, communication from the research institution or other companies of any actual costs incurred during the period that have not yet been invoiced, and the costs included in the contracts. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from the estimates made by the Company. The historical accrual estimates made by the Company have not been materially different from the actual costs. Stock-Based Compensation The Company recognizes compensation expense for stock-based awards, including grants of stock options and restricted stock units, granted to employees, non-employee directors and non-employee consultants based on the estimated fair value on the date of grant, over the requisite service period. The Company recognizes stock-based compensation expense for only the portion of awards that are expected to vest. For awards that vest upon achievement of a performance condition, the Company recognizes compensation expense when achievement of the performance condition is met or during the period from which meeting the condition is deemed probable until the expected date of meeting the performance condition, using management’s best estimates, which consider the inherent risk and uncertainty regarding the future outcomes of the milestones. The fair value of each stock option grant is estimated using the Black-Scholes option-pricing model. Effective January 1, 2020, the Company began using the historical volatility of only its common stock, as there is adequate historical data for the duration of the expected term. The expected term of the stock options granted to employees, non-employee directors and non-employee consultants by the Company has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” stock options. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the date of grant for time periods approximately equal to the expected term of the award. The expected dividend yield is zero , based on the fact that the Company has never paid cash dividends and does not expect to pay any cash dividends in the foreseeable future. The Company also applies a forfeiture rate in order to calculate stock-based compensation expense. Expected forfeitures are based on the historical experience of the Company and management’s expectations of future forfeitures. To the extent actual forfeitures differ from the estimates, the difference is recorded as a cumulative adjustment in the period in which the estimates are revised. Treasury Stock The Company records treasury stock at cost. Treasury stock consists of shares of the Company’s common stock received from a then-employee as consideration for exercises of stock options. Basic and Diluted Net Income (Loss) Per Share Basic net income (loss) per share is computed by dividing the net income (loss) by the weighted average number of shares of common stock that were outstanding during the period. For computing diluted net income (loss) per share, the weighted average number of shares of common stock that were outstanding during the period is adjusted for the dilutive effect of common stock equivalents outstanding for the period by using the treasury stock method. For periods in which the Company has reported net losses, diluted net loss per share is the same as basic net loss per share, because dilutive common shares are not assumed to have been issued if their effect is anti-dilutive. The Company reported a net loss for the years ended December 31, 2022 and 2021. Concentration of Credit Risk and of Significant Suppliers Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash, cash equivalents and marketable securities. The Company maintains accounts for all cash and cash equivalents at accredited financial institutions, in amounts that exceed federally insured limits. The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. The Company is dependent on third-party manufacturers to supply products for research and development activities for its programs. The Company also relies on and expects to continue to rely on third-party manufacturers to supply it with active pharmaceutical ingredients (“API”) and formulated drugs; and to provide other services related to manufacturing activities for these programs. These programs could be adversely affected by a significant interruption in the supply of API and formulated drugs, or the interruption of manufacturing related services. Income Taxes The Company accounts for income taxes under the asset and liability method. Under this method, deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted rates in effect for the year in which these temporary differences are expected to be recovered or settled. Valuation allowances are provided if, based on the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company accounts for uncertain tax positions in accordance with the provisions of Accounting Standards Codification (“ASC”) Topic 740, “ Income Taxes ” (“Topic 740”). When uncertain tax positions exist, the Company recognizes the tax benefit of tax positions to the extent that the benefit will more likely than not be realized. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. The Company accrues for potential interest and penalties related to unrecognized tax benefits in income tax expense. Fair Value Measurements Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Financial assets and liabilities carried at fair value are classified and disclosed in one of the following three categories: Level 1 — Quoted market prices in active markets for identical assets or liabilities. Level 2 — Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The Company’s cash equivalents and marketable securities at December 31, 2022 and 2021 were carried at fair value, determined according to the fair value hierarchy; see Note 3, Fair Value Measurements. The carrying amounts reflected in the consolidated balance sheets for the collaboration receivable – related party, accounts payable and accrued expenses approximate their fair values due to their short-term maturities at December 31, 2022 and 2021 , respectively. Segment Data The Company manages its operations as a single segment for the purposes of assessing performance and making operating decisions. The singular focus of the Company is to pioneer solutions to deliver life-changing brain health medicines, so every person can thrive. Comprehensive Income (Loss) Comprehensive income (loss) includes net income (loss) and other changes in stockholders’ equity that result from transactions and economic events other than those with stockholders. The Company’s only element of other comprehensive income (loss) is unrealized gains and losses on marketable securities that are considered to be available-for-sale. Revenue Recognition The Company generates revenue from the sale of ZULRESSO, which was approved by the FDA in March 2019 and the Company subsequently began selling in June 2019, and from collaboration and supply agreements with the Company’s collaborators. To date, revenue from collaboration agreements has come from initial, upfront payments allocated to licenses of intellectual property delivered to the Company’s collaborators and from the supply of material for clinical trials under a supply agreement. Under ASC Topic 606, Revenue from Contracts with Customers (“Topic 606”), an entity recognizes revenue when or as performance obligations are satisfied by transferring control of promised goods or services to a customer, in an amount that reflects the consideration that the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of Topic 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price, including variable consideration, if any; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. Arrangements that include rights to additional goods or services that are exercisable at a customer’s discretion are generally considered options. The Company assesses if these options provide a material right to the customer and if so, they are considered performance obligations. The exercise of a material right may be accounted for as a contract modification or as a continuation of the contract for accounting purposes. 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. Collaboration and License Revenue In assessing whether a promised good or service is distinct in the evaluation of a collaboration or license arrangement subject to Topic 606, the Company considers factors such as the research, manufacturing and commercialization capabilities of the collaboration partner and the availability of the associated expertise in the general marketplace. The Company also considers the intended benefit of the contract in assessing whether a promised good or service is separately identifiable from other promises in the contract. If a promised good or service is not distinct, the Company is required to combine that good or service with other promised goods or services until it identifies a bundle of goods or services that is distinct. The transaction price is then determined and allocated to the identified performance obligations in proportion to their standalone selling prices (“SSP”) on a relative SSP basis. SSP is determined at contract inception and is not updated to reflect changes between contract inception and when the performance obligations are satisfied. Determining the SSP for performance obligations requires significant judgment. In developing the SSP for a performance obligation, the Company considers applicable market conditions and relevant entity-specific factors, including factors that were contemplated in negotiating the agreement with the customer and estimated costs. In certain circumstances, the Company may apply the residual method to determine the SSP of a good or service if the standalone selling price is considered highly variable or uncertain. The Company validates the SSP for performance obligations by evaluating whether changes in the key assumptions used to determine the SSP will have a significant effect on the allocation of arrangement consideration between multiple performance obligations. If the consideration promised in a contract includes a variable amount, the Company estimates the amount of consideration to which it will be entitled in exchange for transferring the promised goods or services to a customer. The Company determines the amount of variable consideration by using the expected value method or the most likely amount method. The Company includes the unconstrained amount of estimated variable consideration in the transaction price. The amount included in the transaction price is constrained to the amount for which it is probable that a significant reversal of cumulative revenue recognized will not occur. At the end of each subsequent reporting period, the Company re-evaluates the estimated variable consideration included in the transaction price and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis in the period of adjustment. If an arrangement includes development and regulatory milestone payments, the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s control or the licensee’s control, such as regulatory approvals, are generally not considered probable of being achieved until those approvals are received. In determining the transaction price, the Company adjusts consideration for the effects of the time value of money if the timing of payments provides the Company with a significant benefit of financing. The Company does not assess whether a contract has a significant financing component if the expectation at contract inception is such that the period between payment by the licensees and the transfer of the promised goods or services to the licensees will be one year or less. The Company assessed its arrangements with Shionogi 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. For additional information, refer to Note 6, Collaboration Agreements . Product Revenue, Net The Company recognizes product revenue, net of variable consideration related to certain allowances and accruals that are determined using the expected value method, in its consolidated financial statements at the point in time when control transfers to the customer, which is typically when the product has been delivered to the customer’s location. The amount included in the transaction price is constrained to the amount for which it is probable that a significant reversal of cumulative revenue recognized will not occur. The Company’s only performance obligation identified for ZULRESSO is to deliver the product to the location specified by the customer’s order. The Company records shipping and handling costs associated with delivery of product to its customers within selling, general and administrative expenses on its consolidated statements of operations and comprehensive income (loss). The Company expenses incremental costs of obtaining a contract as incurred if the expected amortization period of the asset would be less than one year. If the Company were to incur incremental costs with an amortization period greater than a year, such costs would be capitalized as contract assets, as they are expected to be recovered, and would be expensed by amortizing on a systematic basis that is consistent with the transfer to the customer of the goods or services to which the asset relates. The Company did not have any contract assets (unbilled receivables) at December 31, 2022, as customer invoicing generally occurs before or at the time of revenue recognition. The Company did not have any contract liabilities at December 31, 2022, as the Company did not receive any payments in advance of satisfying its performance obligations to its customers. Amounts billed or invoiced that are considered trade accounts receivable are included in prepaid expenses and other current assets on the consolidated balance sheets. As of December 31, 2022 and 2021, 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 fro

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. Fair Value Measurements The Company’s cash equivalents are classified within Level 1 and Level 2 of the fair value hierarchy. The Company’s investments in marketable securities are classified within Level 2 of the fair value hierarchy. The fair values of the Company’s marketable securities are based on prices obtained from independent pricing sources. Consistent with the fair value hierarchy described in Note 2, Summary of Significant Accounting Policies, marketable securities with validated quotes from pricing services are reflected within Level 2, as they are primarily based on observable pricing for similar assets or other market observable inputs. Typical inputs used by these pricing services include, but are not limited to, reported trades, benchmark yields, issuer spreads, bids, offers or estimates of cash flow, prepayment spreads and default rates. The Company performs validation procedures to ensure the reasonableness of this data. The Company performs its own review of prices received from the independent pricing services by comparing these prices to other sources. After completing the validation procedures, the Company did not adjust or override any fair value measurements provided by the pricing services as of December 31, 2022 and 2021. The following tables summarize the Company’s cash equivalents and marketable securities as of December 31, 2022 and 2021: December 31, 2022 Total Quoted Significant Significant (in thousands) Cash equivalents: Money market funds $ 161,185 $ 161,185 $ — $ — Total cash equivalents 161,185 161,185 — — Marketable securities: U.S. government securities 302,911 — 302,911 — U.S. corporate bonds 354,495 — 354,495 — International corporate bonds 127,248 — 127,248 — U.S. commercial paper 63,114 — 63,114 — International commercial paper 133,163 — 133,163 — U.S. certificates of deposit 15,613 — 15,613 — U.S. municipal securities 113,250 — 113,250 — Total marketable securities 1,109,794 — 1,109,794 — $ 1,270,979 $ 161,185 $ 1,109,794 $ — December 31, 2021 Total Quoted Significant Significant (in thousands) Cash equivalents: Money market funds $ 289,440 $ 289,440 $ — $ — U.S. commercial paper 2,000 — 2,000 — International commercial paper 1,999 — 1,999 — Total cash equivalents 293,439 289,440 3,999 — Marketable securities: U.S. government securities 324,532 — 324,532 — U.S. corporate bonds 627,780 — 627,780 — International corporate bonds 236,812 — 236,812 — U.S. commercial paper 80,176 — 80,176 — International commercial paper 142,335 — 142,335 — U.S. municipal securities 36,428 — 36,428 — Total marketable securities 1,448,063 — 1,448,063 — $ 1,741,502 $ 289,440 $ 1,452,062 $ — During the years ended December 31, 2022 and 2021 , there were no transfers among the Level 1, Level 2 and Level 3 categories. The following tables summarize the gross unrealized gains and losses of the Company’s marketable securities as of December 31, 2022 and 2021: December 31, 2022 Amortized Gross Unrealized Gross Unrealized Credit Losses Fair Value (in thousands) Assets: U.S. government securities $ 307,173 $ — $ ( 4,262 ) $ — $ 302,911 U.S. corporate bonds 358,019 6 ( 3,530 ) — 354,495 International corporate bonds 128,374 7 ( 1,133 ) — 127,248 U.S. commercial paper 63,234 — ( 120 ) — 63,114 International commercial paper 133,338 — ( 175 ) — 133,163 U.S. certificates of deposit 15,613 — — — 15,613 U.S. municipal securities 114,249 31 ( 1,030 ) — 113,250 $ 1,120,000 $ 44 $ ( 10,250 ) $ — $ 1,109,794 December 31, 2021 Amortized Gross Unrealized Gross Unrealized Credit Losses Fair Value (in thousands) Assets: U.S. government securities $ 325,514 $ — $ ( 982 ) $ — $ 324,532 U.S. corporate bonds 628,836 27 ( 1,083 ) — 627,780 International corporate bonds 237,303 — ( 491 ) — 236,812 U.S. commercial paper 80,194 — ( 18 ) — 80,176 International commercial paper 142,358 — ( 23 ) — 142,335 U.S. municipal securities 36,518 — ( 90 ) — 36,428 $ 1,450,723 $ 27 $ ( 2,687 ) $ — $ 1,448,063 The following tables summarize the fair value and the unrealized losses of the Company’s marketable securities that have been in a loss position for either less than twelve months or greater than twelve months as of December 31, 2022 and 2021: December 31, 2022 Less than 12 months Greater than 12 months Total Fair Unrealized Fair Unrealized Fair Unrealized (in thousands) U.S. government securities $ 112,243 $ ( 1,517 ) $ 185,691 $ ( 2,745 ) 297,934 $ ( 4,262 ) U.S. corporate bonds 208,507 ( 1,989 ) 130,633 ( 1,541 ) 339,140 ( 3,530 ) International corporate bonds 50,982 ( 497 ) 68,993 ( 636 ) 119,975 ( 1,133 ) U.S. commercial paper 24,768 ( 120 ) — — 24,768 ( 120 ) International commercial paper 30,987 ( 175 ) — — 30,987 ( 175 ) U.S. municipal securities 86,251 ( 497 ) 14,466 ( 533 ) 100,717 ( 1,030 ) $ 513,738 $ ( 4,795 ) $ 399,783 $ ( 5,455 ) $ 913,521 $ ( 10,250 ) December 31, 2021 Less than 12 months Greater than 12 months Total Fair Unrealized Fair Unrealized Fair Unrealized (in thousands) U.S. government securities $ 309,588 $ ( 982 ) $ — $ — $ 309,588 $ ( 982 ) U.S. corporate bonds 601,475 ( 1,083 ) — — 601,475 ( 1,083 ) International corporate bonds 231,672 ( 491 ) — — 231,672 ( 491 ) U.S. commercial paper 21,968 ( 18 ) — — 21,968 ( 18 ) International commercial paper 35,059 ( 23 ) — — 35,059 ( 23 ) U.S. municipal securities 24,953 ( 90 ) — — 24,953 ( 90 ) $ 1,224,715 $ ( 2,687 ) $ — $ — $ 1,224,715 $ ( 2,687 ) As of December 31, 2022 and 2021, the unrealized losses on the Company’s investments in U.S. government securities, U.S. corporate bonds, and international corporate bonds were caused by interest rate increases. The Company purchased those investments at a premium relative to their face amount. The current credit ratings are all within the guidelines of the investment policy of the Company and the Company does not expect the issuers to settle any security at a price less than the amortized cost basis of the investment. The Company does not intend to sell the investments and it is not probable that the Company will be required to sell the investments before recovery of their amortized cost basis. As of December 31, 2022 , all marketable securities held by the Company had remaining contractual maturities of one year or less, except for U.S. government securities, U.S. corporate bonds, international corporate bonds and municipal securities with a fair value of $ 211.2 million that had maturities of one to two years . As of December 31, 2021 , all marketable securities held by the Company had remaining contractual maturities of one year or less, except for U.S. government securities, U.S. corporate bonds, international corporate bonds and municipal securities with a fair value of $ 436.1 million that had maturities of one to two years . All marketable securities, including those with remaining contractual maturities of more than one year, are classified as current assets on the balance sheet because they are considered to be “available for sale” and the Company can convert them into cash to fund current operations. There have been no impairments of the Company’s assets measured and carried at fair value during the years ended December 31, 2022 and 2021 .

Balance Sheet Components

Balance Sheet Components	12 Months Ended
	Dec. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Components	4. Balance Sheet Components Property and Equipment, net The following table summarizes property and equipment, net, as of December 31, 2022 and 2021: December 31, December 31, 2022 2021 (in thousands) Computer hardware and software $ 1,771 $ 1,391 Furniture and equipment 1,714 1,208 Leasehold improvements 5,508 5,390 8,993 7,989 Less: Accumulated depreciation ( 6,095 ) ( 4,973 ) $ 2,898 $ 3,016 Depreciation expense for the years ended December 31, 2022, 2021 and 2020 was $ 1.1 million, $ 4.2 million and $ 2.6 million, respectively. The useful life for computer hardware and software is three years , furniture and equipment is five years and leasehold improvements is the lesser of the useful life or the term of the respective lease. Accrued Expenses The following tables summarizes accrued expenses as of December 31, 2022 and 2021: December 31, December 31, 2022 2021 (in thousands) Accrued research and development costs $ 32,565 $ 39,147 Employee-related 29,372 18,618 Professional services 10,172 8,893 Other 557 617 $ 72,666 $ 67,275

Leases, Commitments and Conting

Leases, Commitments and Contingencies	12 Months Ended
	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Leases, Commitments and Contingencies	5. Leases, Commitments and Contingencies Operating Leases The Company leases office space and certain equipment. All of the leases recorded on the consolidated balance sheets are operating leases. The Company’s leases have remaining lease terms ranging from less than one year to approximately two years . Some of the leases include options to extend the leases for up to five years . These options were not included for the purpose of determining the right-of-use assets and associated lease liabilities as the Company determined that the renewal of these leases is not reasonably certain so only the original lease term was taken into consideration. The leases do not include any restrictions or covenants that had to be accounted for under the lease guidance. As of January 1, 2020, the Company leased office space in three multi-tenant buildings in Cambridge, Massachusetts, consisting of 63,017 square feet in the first building, under an operating lease that will expire on August 31, 2024 ; 40,419 square feet in the second building, under an operating lease that will expire on August 31, 2024 and 15,975 square feet in the third building, under an operating lease that began on March 1, 2019 and was initially scheduled to expire on February 29, 2024 ; and in a multi-tenant building in Raleigh, North Carolina, consisting of 15,525 square feet under an operating lease that will expire on November 30, 2024 . During the year ended December 31, 2021, the Company terminated the operating lease for office space in the third multi-tenant building in Cambridge, Massachusetts and the remaining right-of-use asset of $ 3.7 million and the associated liabilities related to this lease were de-recognized upon termination of the lease. Additionally, during the year ended December 31, 2021, the Company entered into a sublease for a portion of the leased office space in the second multi-tenant building in Cambridge, Massachusetts. From June 2018 to January 2019, the Company entered into leases for vehicles for field-based employees. These leases were determined to be operating leases and a right-of-use operating asset in the amount of $ 5.3 million was recorded on the balance sheet upon implementation of the new lease standard on January 1, 2019. The leases were for a term of three years and were to expire on various dates through January 31, 2022 . During the year ended December 31, 2020, these leases were terminated as part of the restructuring during April 2020, and the remaining right-of-use asset of $ 2.3 million and the associated liabilities related to these leases were de-recognized upon termination of the leases. During the year ended December 31, 2020, the restricted cash of $ 0.7 million related to these leases was returned to the Company by the lessor. The following table shows the amounts of operating leases in the balance sheets as of December 31, 2022 and 2021: December 31, Balance sheet location Balance sheet caption 2022 2021 (in thousands) Assets Right-of-use operating asset Right-of-use operating asset $ 10,532 $ 16,109 Liabilities Current operating lease Operating lease liability, current portion 7,643 7,468 Long-term operating lease Operating lease liability, net of current portion 4,491 10,964 $ 12,134 $ 18,432 The following table shows the amounts of lease expense by lease type that was recognized during the years ended December 31, 2022, 2021 and 2020: Year Ended December 31, 2022 2021 2020 (in thousands) Operating lease cost $ 6,748 $ 8,748 $ 8,838 Variable lease cost 1,846 1,600 2,285 Short-term lease cost 206 101 74 Sublease income ( 421 ) ( 234 ) - $ 8,379 $ 10,215 $ 11,197 The Company made an accounting policy election not to apply the recognition requirements to short-term leases. The Company recognizes the lease payments for short-term leases as expense on a straight-line basis over the lease term, and variable lease payments in the period in which the obligation for those payments is incurred. The minimum lease payments are expected to be as follows: Years Ending December 31, (In thousands) 2023 $ 7,643 2024 5,316 Thereafter - Total lease payments 12,959 Less imputed interest ( 825 ) Present value of operating lease liabilities $ 12,134 The following table shows the weighted average remaining lease term and weighted average discount rate of the operating leases: Year ended December 31, 2022 2021 Weighted average remaining lease term in years 1.68 2.68 Weighted average discount rate 7.5 % 7.5 % The interest rate implicit in lease contracts is typically not readily determinable and as such, the Company uses its incremental borrowing rate based on the information available at the lease commencement date, which represents an internally developed rate that would be incurred to borrow, on a collateralized basis, over a similar term, an amount equal to the lease payments in a similar economic environment. The following table shows the supplemental disclosure of cash flow information related to the operating leases included in cash flows used by operating activities in the consolidated statements of cash flows: Year Ended December 31, 2022 2021 2020 (in thousands) Cash paid for amounts included in $ 7,468 $ 9,264 $ 9,231 Lease asset de-recognized upon lease Operating leases $ — $ 3,733 $ 2,310 License Agreements CyDex License Agreement In September 2015, the Company amended and restated its existing commercial license agreement with CyDex Pharmaceuticals, Inc. (“CyDex”), a wholly owned subsidiary of Ligand Pharmaceuticals Incorporated. Under the terms of the commercial license agreement as amended and restated, CyDex has granted to the Company an exclusive license to CyDex’s Captisol drug formulation technology and related intellectual property for the manufacture of pharmaceutical products incorporating brexanolone and the Company’s compound known as SAGE-689, and the development and commercialization of the resulting products for the treatment, prevention or diagnosis of any disease or symptom in humans or animals other than (i) the ocular treatment of any disease or condition with a formulation, including a hormone; (ii) topical ocular treatment of inflammatory conditions; (iii) treatment and prophylaxis of fungal infections in humans; and (iv) any ocular treatment for retinal degeneration. The Company is required to pay a royalty to CyDex on sales of brexanolone and will be required to pay a royalty on any sales of SAGE-689, if such product candidate is successfully developed in the future. Royalty rates are in the low single digits based on levels of net sales. From the effective date of the agreement to December 31, 2022 , the Company has paid to CyDex $ 1.0 million for licensing fees, which was recorded as research and development expense. Under the amended and restated license agreement with CyDex, the Company agreed to make milestone payments on the achievement of clinical development and regulatory milestones in the amount of up to $ 0.8 million in clinical milestones and up to $ 3.8 million in regulatory milestones for each of the first two fields with respect to brexanolone; up to $ 1.3 million in clinical milestones and up to $ 8.5 million in regulatory milestones for each of the third and fourth fields with respect to brexanolone; and up to $ 0.8 million in clinical milestones and up to $ 1.8 million in regulatory milestones for one field with respect to SAGE-689. From the effective date of the agreement to December 31, 2022 , the Company has recorded research and development expense and made cash payments of $ 3.6 million related to these clinical development and regulatory milestones and has recorded an intangible asset and made a cash payment of $ 3.0 million related to these regulatory milestones. For the year ended December 31, 2020, additional clinical development milestones were met for the brexanolone program under the license agreement with CyDex, and accordingly, the Company recorded research and development expense and accrued expenses totaling $ 1.3 million. The amount was paid in cash during the year ended December 31, 2021. For the year ended December 31, 2021, an additional clinical development milestone was met under the license agreement with CyDex related to SAGE-689, and accordingly, the Company recorded research and development expense and made a cash payment of $ 0.1 million. Additionally in the year ended December 31, 2021, the Company paid $ 1.3 million for the additional clinical development milestones that were met for the brexanolone program under the license agreement with CyDex in the year ended December 31, 2020. For the year ended December 31, 2022, the Company did not record any expense or intangible asset, or make any milestone payments related to clinical development or regulatory milestones for the brexanolone program or SAGE-689 under the license agreement with CyDex. University of California License Agreements In October 2013, the Company entered into a non-exclusive license agreement with the Regents of the University of California ("the Regents") under which the Company was granted a non-exclusive license to certain clinical data and clinical material related to brexanolone for use in the development and commercialization of biopharmaceutical products in the licensed field, including status epilepticus and postpartum depression. In May 2014, the license agreement was amended to add the treatment of essential tremor to the licensed field of use, materials and milestone fee provisions of the agreement. The Company paid to the Regents clinical development milestones of $ 0.1 million, prior to December 31, 2015; no other milestones are outstanding under this non-exclusive license agreement. The Company is required to pay royalties of less than 1 % on net sales for a period of fifteen years following the sale of the first product developed using the data and materials, and the Company began to pay these royalties in 2019. The license will terminate on the earlier to occur of (i) 27 years after the effective date or (ii) 15 years after the last-derived product is first commercially sold. In June 2015, the Company entered into an exclusive license agreement with the Regents whereby the Company was granted an exclusive license to certain patent rights related to the use of allopregnanolone to treat various diseases. In exchange for such license, the Company paid an upfront payment of $ 50,000 and was required to make payments of $ 15,000 for annual maintenance fees until the calendar year following the first sale of ZULRESSO. The Company is obligated to make milestone payments following the achievement of specified regulatory and sales milestones of up to $ 0.7 million and $ 2.0 million in the aggregate, respectively. The Company pays royalties at a low single digit percentage of net sales of ZULRESSO, subject to specified minimum annual royalty amounts. Unless terminated by operation of law or by acts of the parties under the terms of the agreement, the license agreement will terminate when the last-to-expire patents or last-to-be abandoned patent applications expire, whichever is later. From the effective date of the agreement to December 31, 2022 , the Company has recorded research and development expense and made cash payments of $ 0.3 million related to these regulatory and sales milestones; and has recorded an intangible asset and made a cash payment of $ 0.5 million related to these regulatory and sales milestones. For the years ended December 31, 2022, 2021 and 2020, the Company did no t record any expense or make any milestone payments under the license agreements with the Regents.

Collaboration Agreements

Collaboration Agreements	12 Months Ended
	Dec. 31, 2022
Shionogi Collaboration Agreement [Member]
Collaboration Agreement	6. 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 was probable that the Company will collect the consideration to which the Company was entitled in exchange for the goods or services that will be delivered to Shionogi. The Company determined that the performance obligations in the Shionogi collaboration agreement included the license to zuranolone and the supply of certain materials during the clinical development phase, which includes the supply of API. The performance obligation related to the license to zuranolone was determined to be distinct from other performance obligations and therefore was a separate performance obligation for which control was transferred upon signing. The obligation to provide certain clinical materials, including API for use during the development period, was determined to be a separate performance obligation. Given that Shionogi is not obligated to purchase any minimum amount or quantities of commercial API, the supply of API to Shionogi for commercial use was determined to be an option for Shionogi, rather than a performance obligation of the Company at contract inception and will be accounted for if and when exercised. The Company also determined that there was no separate material right in connection with the supply of API for commercial use as the expected pricing was not at a discount. Given this fact pattern, the Company has concluded the agreement has two performance obligations. Under the clinical supply agreement, the Company is obligated to manufacture and supply to Shionogi (i) clinical quantities of API reasonably required by Shionogi for the development of licensed products in the Shionogi territory and (ii) quantities of drug product reasonably required for use by Shionogi in Phase 1 clinical trials of zuranolone in the Shionogi territory, in the quantities agreed to by the parties. Collaboration revenue from the clinical supply agreement pertains to the clinical material sold under the terms of the clinical supply agreement. The Company records the costs related to the clinical supply agreement in research and development expense on its consolidated statements of operations and comprehensive income (loss). During the years ended December 31, 2022, 2021 and 2020, no collaboration revenue was recognized related to the Company’s agreement with Shionogi. The Company completed the evaluation of the standalone selling prices of each of the performance obligations and determined that the standalone selling price of the license performance obligation was $ 90.0 million. The Company recognized the transaction price allocated to the license performance obligation of $ 90.0 million as revenue upon delivery of the license to Shionogi and resulting ability of Shionogi to use and benefit from the license, which was in the three months ended June 30, 2018. The remaining transaction price related to the performance obligation for the supply of certain clinical material is not significant. The potential milestone payments that the Company is eligible to receive were excluded from the transaction price, as all milestone amounts were fully constrained based on the probability of achievement. The Company will re-evaluate the transaction price at the end of each reporting period and as uncertain events are resolved or other changes in circumstances occur, and, if necessary, adjust its estimate of the transaction price. Biogen In November 2020, the Company entered into the Biogen Collaboration Agreement to jointly develop and commercialize SAGE-217 products for MDD, PPD and other disorders and SAGE-324 products for essential tremor and other disorders. Concurrently, the Company also entered into a stock purchase agreement with BIMA (the “Biogen Stock Purchase Agreement”) under which BIMA purchased shares of the Company’s common stock. The Biogen Collaboration Agreement became effective on December 28, 2020 (the “Effective Date”). Under the terms of the Biogen Collaboration Agreement, the Company granted Biogen co-exclusive licenses to develop and commercialize SAGE-217 products and SAGE-324 products (each, a “Product Class” and together, the “Licensed Products”) in the U.S., an exclusive license to develop and commercialize SAGE-217 products in all countries of the world other than the U.S. and the Shionogi Territory, and an exclusive license to develop and commercialize SAGE-324 products in all countries of the world other than the U.S. The Company refers to the territories outside the U.S. to which Biogen has rights under the Biogen Collaboration Agreement with respect to the applicable Licensed Product as the “Biogen Territory”. In connection with the effectiveness of the Biogen Collaboration Agreement and the closing of the sale of shares to BIMA in December 2020, the Company received $ 1.5 billion in consideration, comprised of an upfront payment of $ 875.0 million and the $ 650.0 million purchase price for 6,241,473 newly issued shares of the Company’s common stock (the “Biogen Shares”). As a result of the purchase of the Biogen Shares, Biogen has become a related party of the Company. The Company is eligible to receive additional payments of up to $ 1.6 billion if certain regulatory and commercial milestones are achieved. The potential future milestone payments for SAGE-217 products include up to $ 475.0 million for the achievement of specified regulatory and commercial milestones, including milestones totaling $ 225.0 million for the first commercial sale of zuranolone in MDD and PPD, and up to $ 300.0 million for the achievement of specified net sales milestones. The potential future milestone payments for SAGE-324 products include up to $ 520.0 million for the achievement of specified regulatory and commercial milestones and up to $ 300.0 million for the achievement of specified net sales milestones. The Company is also eligible to receive tiered royalties on net sales of SAGE-217 products and SAGE-324 products in the Biogen Territory at percentage rates ranging from the high teens to low twenties. Due to the uncertainty of pharmaceutical development and the high historical failure rates generally associated with drug development, the Company may never receive any 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 will consist at all times of an equal number of representatives of each party. The Company and Biogen will 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 will be 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 will be the principal and record sales of SAGE-217 products globally. The Company will be the principal and record sales of SAGE-324 products in the U.S. and Biogen will record sales of SAGE-324 Products in the Biogen Territory. The Company will 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 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. The Company has determined that the supply of API and bulk drug product for the Biogen Territory and API, bulk drug product and final drug product for the U.S. to Biogen will be classified as collaboration revenue – related party in the consolidated statements of operations and comprehensive income (loss). During the years ended December 31, 2022 and 2021, no collaboration revenue – related party was recognized related to the Biogen Collaboration Agreement. Payments to or reimbursements from Biogen related to the co-development, co-commercialization, and co-manufacturing activities and the agreement of the parties to share equally the cost of these activities will be accounted for as an increase to or reduction of research and development expenses or selling, general and administrative expenses, depending on the nature of the activity. During the year ended December 31, 2022, the Company recorded a net reimbursement of $ 75.5 million for the amounts due from Biogen as a reduction of the related operating expense categories in the consolidated statement of operations and comprehensive income (loss). During the year ended December 31, 2021, the Company recorded a net reimbursement of $ 91.1 million for the amounts due from Biogen as a reduction of the related operating expense categories in the consolidated statement of operations and comprehensive income (loss). As of December 31, 2022, the Company recorded a Collaboration Receivable – Related Party of $ 13.7 million in the consolidated balance sheet for the amounts due for the three months ended December 31, 2022. During the year ended December 31, 2022 , no payments were made to Biogen and the Company received $ 80.3 million from Biogen for the amounts due for the three months ended December 31, 2021 and the nine months ended September 30, 2022. The following table summarizes expenses related to the Biogen Collaboration Agreement that were incurred by the Company and the related reimbursement from Biogen, reflected by category of operating expenses: Year Ended December 31, 2022 2021 (in thousands) Expenses related to the Biogen Collaboration Agreement $ 213,524 $ 193,776 Net reimbursement from Biogen reflected in the Research and development expenses ( 73,227 ) ( 79,848 ) Selling, general and administrative expenses ( 2,230 ) ( 11,282 ) ( 75,457 ) ( 91,130 ) Total net expenses related to the Biogen Collaboration $ 138,067 $ 102,646 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. The Company determined that any variable consideration related to clinical development and regulatory 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 noted above, the Company identified three performance obligations in the Biogen Collaboration Agreement: (i) the delivery 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; (ii) the clinical manufacturing supply of API and bulk drug product for SAGE-217 products in the Biogen Territory; and (iii) the clinical manufacturing supply of the API and bulk drug product for SAGE-324 products in the Biogen Territory. The selling price of each performance obligation in the Biogen Collaboration Agreement was determined based on the Company’s SSP with the objective of determining the price at which it would sell such an item if it were to be sold regularly on a standalone basis. The Company allocated the variable consideration related to the manufacturing obligations to the future clinical supply of SAGE-217 products and SAGE 324 products in the Biogen Territory and the remaining fixed consideration to the license obligation. The variable consideration related to the manufacturing obligations was not material. As such, the entirety of the $ 1.1 billion fixed consideration of the transaction price has been 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. The Company recognizes revenue for the license performance obligations at a point in time, that is upon transfer of the licenses to Biogen. As control of these licenses was transferred on the Effective Date and Biogen could begin to use and benefit from the licenses, the Company recognized $ 1.1 billion of license revenue during the year ended December 31, 2020 under the Biogen Collaboration Agreement. The Company will recognize revenue for the clinical manufacturing supply obligations at a point in time, that is upon the delivery of the supply to Biogen. 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, which represented a 40 percent premium over the 30-day volume-weighted average share price as of the last trading day prior to the date the Biogen Collaboration Agreement and Biogen Stock Purchase Agreement were executed in November 2020, 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, lock-up restrictions, and a voting agreement with respect to the Biogen Shares. Pursuant to the terms of the Biogen Stock Purchase Agreement, BIMA has agreed not to, and to cause its affiliates not to, directly or indirectly acquire the Company’s securities, seek or propose a tender or exchange offer or merger between the Company and Biogen, solicit proxies or consents with respect to any matter, or undertake other specified actions, in each case subject to specified conditions. The standstill restrictions 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. BIMA also agreed not to, and to cause its affiliates not to, sell or transfer any of the Biogen Shares for a period of eighteen months from the closing of the sale of the Biogen Shares, which period expired on June 30, 2022, and to limit sales and transfers of the Biogen Shares for an additional eighteen-month period, in each case subject to specified conditions and exceptions. The Company determined the fair value of the common shares issued using an option pricing valuation model to take into consideration the holding period restrictions. The fair value of the Company’s common stock was considered a Level 2 fair value measurement within the fair value hierarchy. The most significant assumptions within the model are the Company’s stock price, the term of the restrictions and the stock price volatility, which is based upon a blend of historical and implied volatility of the Company’s stock. Based on the fair value adjustments made by management, the fair value of the shares issued was determined to be $ 417.5 million, which was $ 232.5 million less than the proceeds received from BIMA for the issuance of the Company’s common stock under the Biogen Stock Purchase Agreement. As such, the $232.5 million in excess proceeds has been included in the $ 1.1 billion transaction price of the Biogen Collaboration Agreement determined above.

Preferred Stock

Preferred Stock	12 Months Ended
	Dec. 31, 2022
Equity [Abstract]
Preferred Stock	7. Preferred Stock The Board of Directors of the Company (the “Board”) is authorized, without action by the stockholders, to designate and issue up to an aggregate of 5,000,000 shares of preferred stock in one or more series. The Board can designate the rights, preferences and privileges of the shares of each series and any of its qualifications, limitations or restrictions. The Board may authorize the issuance of preferred stock with voting or conversion rights that could adversely affect the voting power or other rights of the holders of common stock. As of December 31, 2022 and 2021 , the Company had no shares of preferred stock issued or outstanding and preferred stock was classified as stockholders’ equity.

Common Stock

Common Stock	12 Months Ended
	Dec. 31, 2022
Text Block [Abstract]
Common Stock	8. Common Stock As of December 31, 2022 and 2021 , the Company authorized 120,000,000 shares of common stock with a par value of $ 0.0001 per share. Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders. Common stockholders are entitled to receive dividends, as may be declared by the Board, if any. As of December 31, 2022 and 2021 , no dividends have been declared. On December 31, 2020, the Company completed the sale of 6,241,473 shares of its common stock in a private placement to BIMA at a price of approximately $ 104.14 per share, resulting in aggregate gross proceeds to the Company of $ 650.0 million. For additional information, refer to Note 6, Collaboration Agreements . As of December 31, 2022, the Company had received 3,033 shares of the Company’s common stock from a then-employee as consideration for exercises of stock options. The total cost of shares held in treasury at December 31, 2022 was $ 0.4 million.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	9. Stock-Based Compensation Equity Plans On July 2, 2014, the stockholders of the Company approved the 2014 Stock Option and Incentive Plan (the “2014 Plan”), which became effective immediately prior to the completion of the Company’s IPO. The 2014 Plan provides for the grant of restricted stock awards, restricted stock units, incentive stock options and non-statutory stock options. The 2014 Plan replaced the Company’s 2011 Stock Option and Grant Plan (the “2011 Plan”). The Company no longer grants stock options or other awards under its 2011 Plan, but any stock options outstanding under the 2011 Plan remain outstanding and effective in accordance with their terms. The 2014 Plan provides for an annual increase, to be added on the first day of each fiscal year, by up to 4% of the Company’s outstanding shares of common stock as of the last day of the prior year. On January 1, 2022, 2,357,482 shares of common stock, representing 4 % of the Company’s outstanding shares of common stock as of December 31, 2021, were added to the 2014 Plan. On December 15, 2016, the Board approved the 2016 Inducement Equity Plan (as amended and restated, the “2016 Plan”). The 2016 Plan provides for the grant of equity awards to individuals who have not previously been an employee or a non-employee director of the Company to induce them to accept employment and to provide them with a proprietary interest in the Company. On September 20, 2018, the Board amended the 2016 Plan to increase the total number of shares reserved for issuance by 1,200,000 shares. Terms of equity grants, including vesting requirements, are determined by the Board or the Compensation Committee of the Board, subject to the provisions of the applicable plan. Stock options granted by the Company that are not performance-based are considered time-based because they vest based on the continued service of the grantee with the Company during a specified period following grant. These awards, when granted to employees, generally vest ratably over four years , with 25 % vesting at the one-year anniversary. All stock option awards expire 10 years after the date of grant. As of December 31, 2022, the total number of shares underlying outstanding awards under all equity plans was 9,203,831 and the total number of shares available for future issuance under all equity plans was 7,086,615 shares. Restricted Stock Units The following table summarizes activity relating to time-based restricted stock units and performance restricted stock units: Shares Weighted Average Grant Date Fair Value Outstanding as of December 31, 2021 1,256,098 $ 57.87 Granted 705,380 40.02 Vested ( 366,014 ) 40.13 Forfeited ( 179,983 ) 95.84 Outstanding as of December 31, 2022 1,415,481 48.73 Time-based restricted stock units During the year ended December 31, 2020, the Company granted 550,890 time-based restricted stock units to certain employees of the Company. These time-based restricted stock units vested over two years , with 25 % vesting at the one-year anniversary of the grant date and 75 % vesting at the two-year anniversary of the grant date, which was in April 2021 and April 2022 , respectively. During the year ended December 31, 2021, 113,941 of these time-based restricted stock units vested, with a fair value on the date of vesting equal to $ 8.8 million. During the year ended December 31, 2022, 291,505 of these time-based restricted stock units vested, with a fair value on the date of vesting equal to $ 9.5 million. During the year ended December 31, 2020, no time-based restricted stock units vested. During the year ended December 31, 2021, the Company granted 268,119 time-based restricted stock units to certain employees of the Company. These time-based restricted stock units vest over four years , with 25 % vesting at the one-year anniversary of the vesting start date, which was in September 2022 ; and the remaining 75 % will vest ratably in quarterly increments over the remaining three years . During the year ended December 31, 2022, 74,509 of these time-based restricted stock units vested, with a fair value on the date of vesting equal to $ 2.9 million. During the year ended December 31, 2022, the Company granted no time-based restricted stock units. At December 31, 2022, 160,403 time-based restricted stock units were both outstanding and unvested, and the total unrecognized stock-based compensation expense related to these awards was $ 5.0 million. Performance restricted stock units During the year ended December 31, 2020, the Company granted 471,386 performance restricted stock units to employees of the Company. These performance restricted stock units are related to the achievement of certain clinical and regulatory development milestones related to product candidates and commercial milestones. During the year ended December 31, 2021, the Company granted 531,176 performance restricted stock units to employees of the Company. These performance restricted stock units are related to the achievement of certain clinical and regulatory development milestones related to product candidates and commercial milestones. During the year ended December 31, 2022, the Company granted 705,380 performance restricted stock units to its employees and consultants. These performance restricted stock units are related to the achievement of certain clinical and regulatory development milestones related to product candidates and commercial milestones. Recognition of stock-based compensation expense associated with performance restricted stock units commences when the performance condition is considered probable of achievement, using management’s best estimates, which consider the inherent risk and uncertainty regarding the future outcomes of the milestones. As of December 31, 2022, 2021 and 2020, for performance restricted stock units that were outstanding, the achievement of the milestones that had not been met was considered not probable, and therefore no expense has been recognized related to these awards in the years ended December 31, 2022, 2021 and 2020, respectively. No performance restricted stock units vested during the years ended December 31, 2022 and 2020. During the year ended December 31, 2021, two milestones for outstanding performance restricted stock units were achieved. For the first milestone that was met, the fair value of the performance restricted stock units that vested upon achievement was $ 6.1 million and the Company recognized stock-based compensation expense related to this milestone of $ 3.8 million. 39 % of the performance restricted stock units that were granted during the year ended December 31, 2020 included this milestone as a vesting condition. For the second milestone that was met, the fair value of the performance restricted stock units that vested upon achievement was $ 3.4 million and the Company recognized stock-based compensation expense related to this milestone of $ 12.8 million. 38 % of the performance restricted stock units that were granted during the year ended December 31, 2019 included this milestone as a vesting condition. At December 31, 2022, 1,255,078 performance restricted stock units were both outstanding and unvested, and the total unrecognized stock-based compensation expense related to these awards was $ 62.4 million. Stock Option Rollforward The following table summarizes activity related to time-based and performance-based stock options: Shares Weighted Weighted Average Aggregate Outstanding as of December 31, 2021 7,283,439 $ 84.17 6.74 $ 16,590 Granted 1,181,487 $ 39.45 Exercised ( 156,195 ) $ 7.84 Forfeited ( 520,381 ) $ 98.65 Outstanding as of December 31, 2022 7,788,350 $ 77.95 6.36 $ 7,275 Vested and expected to vest as of December 31, 2022 6,724,505 $ 78.86 6.05 $ 6,917 Exercisable as of December 31, 2022 5,109,027 $ 85.76 5.22 $ 5,607 As of December 31, 2022, the Company had unrecognized stock-based compensation expense related to its outstanding and unvested time-based stock option awards of $ 61.0 million, which is expected to be recognized over the remaining weighted average vesting period of 2.94 years. The intrinsic value of stock options exercised during the years ended December 31, 2022, 2021 and 2020 was $ 4.4 million, $ 9.0 million and $ 2.1 million, respectively. Performance-Based Stock Options Recognition of stock-based compensation expense associated with performance-based stock options commences when the performance condition is considered probable of achievement, using management’s best estimates, which consider the inherent risk and uncertainty regarding the future outcomes of the milestones. As of December 31, 2022, 2021 and 2020, for performance-based stock option grants that were outstanding, the achievement of the milestones that had not been met was considered not probable, and therefore no expense has been recognized related to these awards in the years ended December 31, 2022, 2021 and 2020, respectively. During the year ended December 31, 2021, in connection with the hiring of its chief executive officer, the Company granted 650,000 stock options to its chief executive officer to purchase shares of common stock that contain performance-based vesting criteria, such that the shares underlying such stock options will vest upon the achievement of certain regulatory and commercial milestones. During the years ended December 31, 2022 and 2020, the Company granted no stock options to purchase shares of common stock that contain performance-based vesting criteria. During the years ended December 31, 2022, 2021 and 2020, no milestones were achieved under performance-based stock options. As of December 31, 2022, 650,000 performance-based stock options were both outstanding and unvested, the total unrecognized stock-based compensation expense related to these awards was $ 8.2 million and the timing of recognition of this stock-based compensation expense is subject to judgment of the Company as to when the performance conditions are considered probable of being achieved. Stock-Based Compensation Expense The following table summarizes stock-based compensation expense recognized during the years ended December 31, 2022, 2021 and 2020: Year Ended December 31, 2022 2021 2020 (in thousands) Research and development $ 25,888 $ 49,746 $ 42,370 Selling, general and administrative 35,714 54,883 51,836 Restructuring — — 1,788 $ 61,602 $ 104,629 $ 95,994 The following table summarizes stock-based compensation expense by award type recognized during the years ended December 31, 2022, 2021 and 2020: Year Ended December 31, 2022 2021 2020 (in thousands) Stock options $ 54,971 $ 78,516 $ 90,064 Restricted stock units 5,587 25,375 4,904 Employee stock purchase plan 1,044 738 1,026 $ 61,602 $ 104,629 $ 95,994 The stock-based compensation expense recorded for the restructuring in the year ended December 31, 2020 is the incremental amount related to modifying the exercise period for outstanding, vested stock option grants that had been granted to employees whose employment was terminated in the restructuring. 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 years ended December 31, 2022, 2021 and 2020 was $ 25.96 , $ 51.87 and $ 37.53 , respectively. The fair value of each stock option granted under the Company’s equity plans has been calculated on the date of grant using the following weighted average assumptions: Year Ended December 31, 2022 2021 2020 Expected dividend yield 0 % 0 % 0 % Expected volatility 73 % 76 % 78 % Risk-free interest rate 2.49 % 0.63 % 0.97 % Expected term 6.03 years 5.92 years 5.98 years Expected dividend yield: the Company has not paid, and does not anticipate paying, any dividends in the foreseeable future. Risk-free interest rate: the Company determined the risk-free interest rate by using a weighted average equivalent to the expected term based on the U.S. Treasury yield curve in effect as of the date of grant. Expected volatility: effective January 1, 2020, the Company began using the historical volatility of only its common stock, as there is adequate historical data for the duration of the expected term. Expected term (in years): the expected term represents the period that the Company’s stock option grants are expected to be outstanding. The expected term of the stock options granted to employees, non-employee directors and non-employee consultants by the Company has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” stock options. Under this approach, the weighted average expected life is presumed to be the average of the vesting term and the contractual term of the stock option. This approach is used because the Company does not have sufficient historical exercise data to provide a reasonable basis upon which to estimate the expected term due to the limited period of time that its stock has been publicly traded. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from estimates. The Company estimates forfeitures based on historical terminations. For the years ended December 31, 2022, 2021 and 2020, the weighted-average forfeiture rates were 19.2 % , 16.7 % and 20.6 % , respectively. 2014 Employee Stock Purchase Plan On July 2, 2014, the Company’s stockholders approved the 2014 Employee Stock Purchase Plan (the “ESPP”), which had been previously approved by the Board. The ESPP became effective upon the completion of the IPO. A total of 282,000 shares of common stock were authorized for issuance under the ESPP. On June 16, 2022, the Company's stockholders approved an amendment to the ESPP to add 300,000 shares of common stock to the ESPP. As of December 31, 2022, 281,877 shares have been issued and 300,123 shares are available for issuance under the ESPP. At December 31, 2022, accrued expenses includes $ 0.8 million of stock-based compensation expense related to an enrollment period for which the related shares had not been issued as of December 31, 2022 .

Net Income (Loss) Per Share

Net Income (Loss) Per Share	12 Months Ended
	Dec. 31, 2022
Earnings Per Share [Abstract]
Net Income (Loss) Per Share	10. Net Income (Loss) Per Share The following table shows the calculation of basic and diluted net income (loss) per share for the years ended December 31, 2022, 2021 and 2020: Year Ended December 31, 2022 2021 2020 Basic net income (loss) per share: Numerator: Net income (loss) (in thousands) $ ( 532,784 ) $ ( 457,892 ) $ 606,073 Denominator: Weighted average common stock outstanding 59,306,094 58,670,230 51,983,188 Effect of dilutive securities: Stock options — — 721,791 Restricted stock units — — 292,241 Employee Stock Purchase Plan — — 5,895 Total dilutive securities — — 1,019,927 Weighted average common stock outstanding 59,306,094 58,670,230 53,003,115 Net income (loss) per share—basic $ ( 8.98 ) $ ( 7.80 ) $ 11.66 Net income (loss) per share—diluted $ ( 8.98 ) $ ( 7.80 ) $ 11.43 The following table summarizes common stock equivalents outstanding that were excluded from the calculation of diluted net loss per share because including them would have been anti-dilutive as of December 31, 2022, 2021 and 2020: Year Ended December 31, 2022 2021 2020 Stock options 7,138,350 6,599,429 4,781,737 Restricted stock units 160,403 563,334 — Employee stock purchase plan 76,105 23,625 — 7,374,858 7,186,388 4,781,737 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 common stock equivalents outstanding.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Income Taxes	11. Income Taxes Income (loss) before income tax expense consists of the following: Year Ended December 31, 2022 2021 2020 (in thousands) Domestic $ ( 532,539 ) $ ( 457,693 ) $ 639,986 Foreign ( 245 ) ( 199 ) ( 33,913 ) $ ( 532,784 ) $ ( 457,892 ) $ 606,073 There is no current or deferred provision for income taxes because the Company has historically incurred and utilized operating losses prior to the year ended December 31, 2022. As of December 31, 2022, the Company continues to maintain a full valuation allowance against its net deferred tax assets. The reported amount of income tax expense for the years differs from the amount that would result from applying domestic federal statutory tax rates to pretax losses primarily because of changes in the valuation allowance. A reconciliation of the U.S. statutory rate to the Company’s effective tax rate is as follows: Year Ended December 31, 2022 2021 2020 Tax due at statutory rate 21.0 % 21.0 % 21.0 % State taxes, net of federal 1.8 1.9 5.7 Biogen transaction-related items — — ( 10.1 ) Stock-based compensation ( 1.9 ) ( 5.2 ) 0.9 Foreign rate differential — — 1.2 Federal and state tax credits 2.1 3.5 ( 1.5 ) Change in valuation allowance ( 23.0 ) ( 20.7 ) ( 17.6 ) Other — ( 0.5 ) 0.4 0.0 % 0.0 % 0.0 % For the years ended December 31, 2022 and 2021, the impact from stock-based compensation on the Company’s effective tax rate was primarily caused by shortfalls related to exercises and cancellations of non-qualified stock options. For the year ended December 31, 2020, the Biogen transaction-related items consisted primarily of the excess proceeds from the equity investment under the Biogen Stock Purchase Agreement. Significant components of the Company’s net deferred tax assets at December 31, 2022 and 2021 are as follows: December 31, 2022 2021 (in thousands) Net operating losses $ 347,880 $ 305,824 Tax credits 118,393 106,176 Capitalized research and development expenses 66,849 — Stock-based compensation 49,916 49,281 Accrued expenses 8,750 6,684 Depreciation and amortization 1,386 1,401 Right of use asset ( 2,433 ) ( 3,702 ) Lease liability 2,803 4,236 Other ( 258 ) 704 Total net deferred tax asset before valuation 593,286 470,604 Valuation allowance ( 593,286 ) ( 470,604 ) $ — $ — On December 22, 2017, the Tax Cuts and Jobs Act (the "TCJA") was signed into law. Under the TCJA provisions, effective with tax years beginning on or after January 1, 2022, taxpayers can no longer immediately expense qualified research and development expenditures. Taxpayers are now required to capitalize and amortize these costs over five years for research conducted within the United States or 15 years for research conducted abroad. As a result, the Company capitalized $ 319.0 million of research and development expenses for the year ended December 31, 2022. On August 16, 2022, the Inflation Reduction Act of 2022 (the "IRA") was signed into law. The IRA introduced new tax provisions, including a 15.0 % corporate alternative minimum tax and a 1.0 % excise tax on stock repurchases. The provisions of the IRA will be effective for periods after December 31, 2022. The enactment of the IRA did not result in any material adjustments to our income tax provision or net deferred tax assets as of December 31, 2022. As of December 31, 2022, the Company had federal net operating loss carryforwards of $ 1.5 billion, of which $ 30.2 million begin to expire in 2033 and the remainder do not expire but are subject to 80 % limitation. As of December 31, 2022, the Company had state net operating loss carryforwards of $ 669.5 million that begin to expire in 2031 . As of December 31, 2022, the Company had federal and state research and development tax credits carryforwards of $ 68.4 million and $ 12.5 million, respectively, which begin to expire in 2031 and 2027 , respectively. As of December 31, 2022, the Company had federal orphan drug tax credit carryforwards of $ 40.1 million, which begin to expire in 2034 . As of December 31, 2022, net deferred tax assets before the valuation allowance increased $ 122.7 million, primarily due to the capitalization of research and development expenses and the increase of federal and state net operating loss carryforwards due to the loss generated for the year ended December 31, 2022. This increase in net deferred tax assets was offset by a corresponding increase in the valuation allowance. Management of the Company has evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets, which are comprised principally of federal and state net operating loss and tax credit carryforwards. Under the applicable accounting standards, management has considered the Company’s history of losses and concluded that it is more likely than not that the Company will not recognize the benefits of its federal and state deferred tax assets. Accordingly, a full valuation allowance of $ 593.3 million and $ 470.6 million has been established at December 31, 2022 and 2021, respectively. The valuation allowance increased by $ 122.7 million for the year ended December 31, 2022, primarily due to the capitalization of research and development expenses and generation of net operating losses. The valuation allowance increased by $ 94.5 million and decreased by $ 107.2 million for the years ended December 31, 2021 and 2020, respectively, primarily due to generation or utilization of net operating losses. Pursuant to Section 382 of the Internal Revenue Code, and similar state tax law, certain substantial changes in the Company’s ownership may result in a limitation on the amount of net operating loss and tax credit carryforwards that may be used in future years. Utilization of the net operating loss and tax credit carryforwards may be subject to a substantial annual limitation under Section 382 of the Internal Revenue Code of 1986, as amended, due to ownership change limitations that have occurred previously or that could occur in the future. These ownership changes may limit the amount of net operating loss and tax credit carryforwards that can be utilized annually to offset future taxable income and tax, respectively. The Company completed a Section 382 study through December 31, 2020. Based on the study, the Company underwent two ownership changes for Section 382 purposes which occurred on March 11, 2014 and December 31, 2015. As a result of the ownership changes, the Company’s net operating loss and tax credit carryforwards as of the ownership change dates are subject to limitation under Section 382; however, these limitations are not expected to cause any of the impacted net operating loss and tax credit carryforwards to expire unused. Any net operating losses or tax credits generated after the December 2015 change are not subject to this annual limitation. However, subsequent ownership changes, as defined by Section 382, may potentially further limit the amount of net operating loss and tax credit carryforwards that could be utilized to offset future taxable income and tax. The Company applies the authoritative guidance on accounting for and disclosure of uncertainty in tax positions, which requires the Company to determine whether a tax position of the Company is more likely than not to be sustained upon examination, including resolution of any related appeals of litigation processes, based on the technical merits of the position. For tax positions meeting the more likely than not threshold, the tax amount recognized in the financial statements is reduced by the largest benefit that has a greater than fifty percent likelihood of being realized upon the ultimate settlement with the relevant taxing authority. The following table reconciles the beginning and ending amounts of gross unrecognized tax benefits, excluding interest and penalties, if any, for the years ended December 31, 2022 and 2021: 2022 2021 (in thousands) Balance as of January 1 $ 6,084 $ - Increases related to current year tax positions 697 396 Increases related to prior year tax positions 65 5,688 Balance as of December 31 $ 6,846 $ 6,084 For the years ended December 31, 2022 and 2021, the increases in unrecognized tax benefits related to current year and prior year tax positions primarily related to the Company’s federal and state tax credits. The Company’s policy is to record interest and penalties related to income taxes as part of the tax provision. As of December 31, 2022 and 2021 , the Company had no accrued interest or penalties related to income taxes and no amounts have been recognized in the Company’s statements of operations and comprehensive income (loss) for the years ended December 31, 2022, 2021 and 2020. The Company files tax returns as prescribed by the tax laws of the jurisdictions in which it operates. In the normal course of business, the Company is subject to examination by federal, state and foreign jurisdictions, where applicable. There are currently no pending tax examinations, and the Company’s tax returns are generally open under statute from 2019 to the present. Tax attributes such as net operating losses and tax credits generated prior to 2019 and utilized in open years may still be adjusted upon examination.

Employee Benefit Plan

Employee Benefit Plan	12 Months Ended
	Dec. 31, 2022
Postemployment Benefits [Abstract]
Employee Benefit Plan	12. Employee Benefit Plan The Company maintains a 401(k) profit sharing plan (the “401(k) Plan”) for its employees. Each employee may elect to contribute a portion of his or her compensation to the 401(k) Plan, subject to annual limits established by the Internal Revenue Service. For the years ended December 31, 2022, 2021 and 2020 , the Company matched 50 % of eligible contributions to the 401(k) Plan up to 6 % of employee contributions. For the years ended December 31, 2022, 2021 and 2020 the Company contributed $ 3.0 million, $ 1.8 million and $ 2.2 million, respectively, to the 401(k) Plan.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Risks and Uncertainties	Risks and Uncertainties The Company is subject to risks and uncertainties common to companies in the biotechnology and pharmaceutical industries, 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 impact of the COVID-19 pandemic on its development activities, operations and financial condition. The product candidates developed by the Company require approvals from the FDA or foreign regulatory agencies prior to commercial sales. There can be no assurance that the current and future product candidates of the Company will receive, or that the Company’s current product, ZULRESSO, 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, including zuranolone, 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 related to the ongoing COVID-19 pandemic and other macroeconomic and geopolitical events, which collectively have caused and may continue to cause major disruptions to businesses and economies worldwide. The rapid spread of COVID-19 in the U.S. resulted in a significant reduction in patient demand for ZULRESSO and in the number of sites available to administer ZULRESSO at certain points during the pandemic. There have been and continue to be healthcare staffing shortages and other changes to the macroeconomic environment as downstream effects of the pandemic have continued. These factors have had a significant and sustained negative impact on the Company’s revenue from sales of ZULRESSO. While the Company has not experienced any other material disruptions to date as a result of the COVID-19 pandemic, any prolonged material disruptions to the work of the Company’s employees, suppliers, contract manufacturers, or vendors could negatively impact the Company’s activities, availability of supplies, or operating results. In addition, while the Company has seen slower patient recruitment in certain clinical trials due to the COVID-19 pandemic and its downstream effects, and has experienced some challenges in qualifying and activating clinical trial sites, including due to capacity and resource constraints and employee attrition at our vendors and at sites, the Company has not experienced other significant impacts to the Company’s development activities as a result of the COVID-19 pandemic. Any material disruption to the Company’s development activities may cause delays, increase the Company’s costs and impact the Company’s operating results. In addition, the COVID-19 pandemic initially caused major volatility in capital markets and a significant global economic downturn, and the Company’s ability to access the capital markets in the future could be negatively impacted if there are long-term negative effects of the COVID-19 pandemic on the macroeconomic environment or capital markets. Moreover, U.S. and global financial markets have experienced volatility and disruption due to other macroeconomic and geopolitical events such as rising inflation, the risk of a recession and the ongoing conflict between Russia and Ukraine. 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 MA Inc. (“BIMA”) and Biogen International GmbH (collectively with BIMA, “Biogen”) (the “Biogen Collaboration Agreement”). As of December 31, 2022, the Company had an accumulated deficit of $ 2.0 billion. From its inception through December 31, 2022, the Company has received aggregate net proceeds of $ 2.8 billion from the sales of redeemable convertible preferred stock prior to its initial public offering (“IPO”), the issuance of convertible notes, and the sales of common stock in its IPO in July 2014, in follow-on public offerings and to BIMA under a stock purchase agreement executed in connection with the Biogen Collaboration Agreement. The Company has also received $ 1.0 billion in upfront payments under its collaborations with Biogen and Shionogi & Co., Ltd. (“Shionogi”). Until such time, if ever, as the Company can generate substantial product revenue and/or collaboration revenue and achieve sustained profitability, the Company expects to finance its cash needs through a combination of equity offerings, debt financings, collaborations, strategic alliances, licensing arrangements and other sources of funding. If the Company is unable to raise additional funds through equity or debt financings or other sources of funding when needed, the Company may be required to delay, limit, reduce or terminate product development or future commercialization efforts or grant rights to develop and market products or product candidates that the Company would otherwise prefer to develop and market itself. The Company expects that, based on its current operating plans, the Company’s existing cash, cash equivalents and marketable securities will be sufficient to fund its currently planned operations for at least the next 12 months from the filing date of this Annual Report. At some point after that time, the Company anticipates it will require additional financing to fund its future operations. Even if the Company believes it has sufficient funds for its current or future operating plans, the Company may seek to raise additional capital if market conditions are favorable or in light of other strategic considerations.
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements include those of the Company and its subsidiaries after elimination of all intercompany accounts and transactions. The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the U.S. (“GAAP”).
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. Intercompany accounts and transactions have been eliminated.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. The full extent to which the COVID-19 pandemic and its downstream effects may directly or indirectly impact the Company’s business, results of operations and financial condition, including sales, expenses, reserves and allowances, manufacturing, clinical trials, research and development costs and employee-related amounts, will depend in large part on future developments, which cannot be predicted with confidence at this time, including: the scope, duration and severity of ongoing and future waves of the pandemic, including the impact of any variant strains of the COVID-19 virus; the extent of healthcare staffing shortages that have continued even as COVID-19 related restrictions have eased; the impact of the pandemic on the Company’s customers and vendors, including capacity and resource constraints; the impact of the downstream effects of the pandemic on business operations across the U.S.; and the scope and extent of any future actions or restrictive measures taken to contain or mitigate the impact of the pandemic . The Company has made estimates of the impact of the COVID-19 pandemic within its consolidated financial statements. Due to the evolving nature of the COVID-19 pandemic, its downstream effects, and their impacts, there may be changes to those estimates in future periods, and a ctual results could differ from those estimates.
Cash Equivalents	Cash Equivalents The Company considers all highly liquid investments with an original maturity of 90 days or less to be cash equivalents. As of December 31, 2022, cash equivalents were comprised of money market funds. As of December 31, 2021 , cash equivalents were comprised of money market funds, U.S. commercial paper and international commercial paper.
Marketable Securities	Marketable Securities Marketable securities consist of investments with original maturities greater than 90 days. The Company has classified its investments with maturities beyond one year as short-term, based on their highly liquid nature and because such marketable securities represent the investment of cash that is available for current operations. The Company considers its investment portfolio of marketable securities to be available-for-sale. Accordingly, these investments are recorded at fair value, which is based on quoted market prices. Unrealized gains and losses are reported as the accumulated other comprehensive items in stockholders’ equity. When the fair value is below the amortized cost of the asset, an estimate of expected credit losses is made. The credit-related impairment amount is recognized in net income (loss); the remaining impairment amount and unrealized gains are reported as a component of accumulated other comprehensive items in stockholders’ equity. Credit losses are recognized through the use of an allowance for credit losses account and subsequent improvements in expected credit losses are recognized as a reversal of an amount in the allowance for credit losses account. If the Company has the intent to sell the security or it is more likely than not that the Company will be required to sell the security prior to recovery of its amortized cost basis, then the allowance for the credit loss is written-off and the excess of the amortized cost basis of the asset over its fair value is recorded in the consolidated statements of operations and comprehensive income (loss). Regardless of the Company’s intent to sell a security, it performs additional analysis on all securities with unrealized losses to evaluate losses associated with the creditworthiness of the security. Credit losses are identified where the Company does not expect to receive cash flows sufficient to recover the amortized cost basis of a security.
Accounts Receivable	Accounts Receivable The Company’s trade accounts receivable consist of amounts due from specialty distributors, specialty pharmacies, and medically-supervised healthcare settings that have been certified under a Risk Evaluation and Mitigation Strategy (“REMS”) program in the U.S. related to sales of ZULRESSO and have standard payment terms that generally require payment within 30 to 90 days from the invoice date. The Company monitors the financial performance and creditworthiness of customers so that it can properly assess and respond to changes in their credit profiles. The Company makes judgments as to its ability to collect outstanding receivables and provides an allowance for bad debts against the trade account receivables, when appropriate. As of December 31, 2022 and 2021, trade accounts receivable were $ 1.5 million and $ 1.1 million, respectively, and are included in prepaid expenses and other current assets on the consolidated balance sheets. As of December 31, 2022 , the Company has not provided any allowance for bad debts against the trade accounts receivable.
Inventory	Inventory Prior to the initial date that regulatory approval is received for a product candidate of the Company, costs related to the production of inventory are recorded as research and development expense on the Company’s consolidated statements of operations and comprehensive income (loss) in the period incurred. In connection with the FDA approval of ZULRESSO in March 2019, the Company subsequently began capitalizing inventory manufactured or purchased after this date. Inventory is stated at the lower of cost or estimated net realizable value with cost determined on a first-in, first-out basis. Inventory costs include raw materials, third-party contract manufacturing, third-party packaging services, and freight. Raw and intermediate materials that may be utilized for either research and development or commercial purposes, after approval of the product by the FDA, are classified as inventory. Amounts in inventory that are used for research and development purposes are charged to research and development expense when the product enters the research and development process and can no longer be used for commercial purposes and, therefore, does not have an “alternative future use” as defined in authoritative guidance. The Company performs an assessment of the recoverability of capitalized inventory during each reporting period and, if needed, writes down any excess and obsolete inventory to its estimated net realizable value in the period it is identified. If they occur, such impairment charges are recorded as a component of cost of goods sold in the consolidated statements of operations and comprehensive income (loss). As of December 31, 2022 and 2021, inventory was $ 1.7 million and $ 1.4 million, respectively, and are included in prepaid expenses and other current assets on the consolidated balance sheets.
Property and Equipment	Property and Equipment Property and equipment are recorded at cost and depreciated over their estimated useful lives using the straight-line method. Upon retirement or sale, the cost of assets disposed of and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is credited or charged to the Company's consolidated statements of operations and comprehensive income (loss). Repairs and maintenance costs are expensed as incurred.
Leases	Leases The Company determines if an arrangement is a lease at contract inception. Operating lease assets represent the Company’s right to use an underlying asset for the lease term and operating lease liabilities represent the Company’s obligation to make payments arising from the lease. Operating lease assets and liabilities are recognized at the commencement date of the lease based upon the present value of lease payments over the lease term. When determining the lease term, the Company includes options to extend or terminate the lease when it is reasonably certain that the Company will exercise those options. The Company uses the Company’s incremental borrowing rate when the implicit interest rate is not readily determinable based upon the information available at the commencement date of the lease in determining the present value of the lease payments and the implicit interest rate when readily determinable. The lease payments used to determine the Company’s operating lease assets may include lease incentives, stated rent increases and escalation clauses linked to rates of inflation, when determinable, and are recognized in the Company’s operating lease assets in the Company’s consolidated balance sheets. In addition, the Company’s contracts may contain lease and non-lease components. The Company combines lease and non-lease components, which are accounted for together as lease components. The Company’s operating leases are reflected in the right-of-use operating asset; operating lease liability, current portion; and operating lease liability, net of current portion in the Company’s consolidated balance sheets. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. Short-term leases, defined as leases that have a lease term of 12 months or less at the commencement date, are not recorded on the Company’s consolidated balance sheets and are recognized in the consolidated statements of operations and comprehensive income (loss) on a straight-line basis over the term of the lease. Variable lease payments are the amounts owed by the Company to a lessor that are not fixed, such as reimbursement for common area maintenance and utilities costs for facility leases. Variable lease payments are expensed when incurred.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets Long-lived assets consist of property and equipment. Long-lived assets to be held and used are tested for recoverability whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends, and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long-lived asset group for recoverability, the Company compares forecasts of undiscounted cash flows expected to result from the use and eventual disposition of the long-lived asset group to its carrying value. The impairment loss would be based on the excess of the carrying value of the impaired asset over its fair value, determined based on discounted cash flows. To date, the Company has not recorded any impairment losses on long-lived assets.
Cost of Goods Sold	Cost of Goods Sold Cost of goods sold includes direct and indirect costs related to the manufacturing and distribution of ZULRESSO, including third-party manufacturing costs, packaging services, freight, third-party royalties payable on the Company’s net product revenue and amortization of intangible assets associated with ZULRESSO. Cost of goods sold may also include period costs related to certain inventory manufacturing services, inventory adjustment charges, as well as manufacturing variances. In connection with the FDA approval of ZULRESSO in March 2019, the Company subsequently began capitalizing inventory manufactured or purchased after this date. As a result, certain manufacturing costs associated with product shipments of ZULRESSO were expensed prior to FDA approval and, therefore, are not included in cost of goods sold during the years ended December 31, 2022 and 2021 .
Research and Development Costs and Accruals	Research and Development Costs and Accruals Research and development expenses are comprised of costs incurred in performing research and development activities, including salaries and benefits, overhead costs, depreciation, contract services and other related costs. Research and development costs are expensed to operations as the related obligation is incurred. The Company has entered into various research and development contracts with research institutions and other companies both inside and outside of the U.S. These agreements are generally cancelable, and related costs are recorded as research and development expenses as incurred. The Company records accruals for estimated ongoing research and development costs. When billing terms under these contracts do not coincide with the timing of when the work is performed, the Company is required to make estimates of outstanding obligations to those third parties as of the end of the reporting period. Any accrual estimates are based on a number of factors, including the Company’s knowledge of the progress towards completion of the research and development activities, invoicing to date under the contracts, communication from the research institution or other companies of any actual costs incurred during the period that have not yet been invoiced, and the costs included in the contracts. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from the estimates made by the Company. The historical accrual estimates made by the Company have not been materially different from the actual costs.
Stock-Based Compensation	Stock-Based Compensation The Company recognizes compensation expense for stock-based awards, including grants of stock options and restricted stock units, granted to employees, non-employee directors and non-employee consultants based on the estimated fair value on the date of grant, over the requisite service period. The Company recognizes stock-based compensation expense for only the portion of awards that are expected to vest. For awards that vest upon achievement of a performance condition, the Company recognizes compensation expense when achievement of the performance condition is met or during the period from which meeting the condition is deemed probable until the expected date of meeting the performance condition, using management’s best estimates, which consider the inherent risk and uncertainty regarding the future outcomes of the milestones. The fair value of each stock option grant is estimated using the Black-Scholes option-pricing model. Effective January 1, 2020, the Company began using the historical volatility of only its common stock, as there is adequate historical data for the duration of the expected term. The expected term of the stock options granted to employees, non-employee directors and non-employee consultants by the Company has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” stock options. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the date of grant for time periods approximately equal to the expected term of the award. The expected dividend yield is zero , based on the fact that the Company has never paid cash dividends and does not expect to pay any cash dividends in the foreseeable future. The Company also applies a forfeiture rate in order to calculate stock-based compensation expense. Expected forfeitures are based on the historical experience of the Company and management’s expectations of future forfeitures. To the extent actual forfeitures differ from the estimates, the difference is recorded as a cumulative adjustment in the period in which the estimates are revised.
Treasury Stock	Treasury Stock The Company records treasury stock at cost. Treasury stock consists of shares of the Company’s common stock received from a then-employee as consideration for exercises of stock options.
Basic and Diluted Net Loss Per Share	Basic and Diluted Net Income (Loss) Per Share Basic net income (loss) per share is computed by dividing the net income (loss) by the weighted average number of shares of common stock that were outstanding during the period. For computing diluted net income (loss) per share, the weighted average number of shares of common stock that were outstanding during the period is adjusted for the dilutive effect of common stock equivalents outstanding for the period by using the treasury stock method. For periods in which the Company has reported net losses, diluted net loss per share is the same as basic net loss per share, because dilutive common shares are not assumed to have been issued if their effect is anti-dilutive. The Company reported a net loss for the years ended December 31, 2022 and 2021.
Concentration of Credit Risk and of Significant Suppliers	Concentration of Credit Risk and of Significant Suppliers Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash, cash equivalents and marketable securities. The Company maintains accounts for all cash and cash equivalents at accredited financial institutions, in amounts that exceed federally insured limits. The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. The Company is dependent on third-party manufacturers to supply products for research and development activities for its programs. The Company also relies on and expects to continue to rely on third-party manufacturers to supply it with active pharmaceutical ingredients (“API”) and formulated drugs; and to provide other services related to manufacturing activities for these programs. These programs could be adversely affected by a significant interruption in the supply of API and formulated drugs, or the interruption of manufacturing related services.
Income Taxes	Income Taxes The Company accounts for income taxes under the asset and liability method. Under this method, deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted rates in effect for the year in which these temporary differences are expected to be recovered or settled. Valuation allowances are provided if, based on the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company accounts for uncertain tax positions in accordance with the provisions of Accounting Standards Codification (“ASC”) Topic 740, “ Income Taxes ” (“Topic 740”). When uncertain tax positions exist, the Company recognizes the tax benefit of tax positions to the extent that the benefit will more likely than not be realized. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. The Company accrues for potential interest and penalties related to unrecognized tax benefits in income tax expense.
Fair Value Measurements	Fair Value Measurements Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Financial assets and liabilities carried at fair value are classified and disclosed in one of the following three categories: Level 1 — Quoted market prices in active markets for identical assets or liabilities. Level 2 — Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The Company’s cash equivalents and marketable securities at December 31, 2022 and 2021 were carried at fair value, determined according to the fair value hierarchy; see Note 3, Fair Value Measurements. The carrying amounts reflected in the consolidated balance sheets for the collaboration receivable – related party, accounts payable and accrued expenses approximate their fair values due to their short-term maturities at December 31, 2022 and 2021 , respectively.
Segment Data	Segment Data The Company manages its operations as a single segment for the purposes of assessing performance and making operating decisions. The singular focus of the Company is to pioneer solutions to deliver life-changing brain health medicines, so every person can thrive.
Comprehensive Income (Loss)	Comprehensive Income (Loss) Comprehensive income (loss) includes net income (loss) and other changes in stockholders’ equity that result from transactions and economic events other than those with stockholders. The Company’s only element of other comprehensive income (loss) is unrealized gains and losses on marketable securities that are considered to be available-for-sale.
Revenue Recognition	Revenue Recognition The Company generates revenue from the sale of ZULRESSO, which was approved by the FDA in March 2019 and the Company subsequently began selling in June 2019, and from collaboration and supply agreements with the Company’s collaborators. To date, revenue from collaboration agreements has come from initial, upfront payments allocated to licenses of intellectual property delivered to the Company’s collaborators and from the supply of material for clinical trials under a supply agreement. Under ASC Topic 606, Revenue from Contracts with Customers (“Topic 606”), an entity recognizes revenue when or as performance obligations are satisfied by transferring control of promised goods or services to a customer, in an amount that reflects the consideration that the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of Topic 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price, including variable consideration, if any; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. Arrangements that include rights to additional goods or services that are exercisable at a customer’s discretion are generally considered options. The Company assesses if these options provide a material right to the customer and if so, they are considered performance obligations. The exercise of a material right may be accounted for as a contract modification or as a continuation of the contract for accounting purposes. 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. Collaboration and License Revenue In assessing whether a promised good or service is distinct in the evaluation of a collaboration or license arrangement subject to Topic 606, the Company considers factors such as the research, manufacturing and commercialization capabilities of the collaboration partner and the availability of the associated expertise in the general marketplace. The Company also considers the intended benefit of the contract in assessing whether a promised good or service is separately identifiable from other promises in the contract. If a promised good or service is not distinct, the Company is required to combine that good or service with other promised goods or services until it identifies a bundle of goods or services that is distinct. The transaction price is then determined and allocated to the identified performance obligations in proportion to their standalone selling prices (“SSP”) on a relative SSP basis. SSP is determined at contract inception and is not updated to reflect changes between contract inception and when the performance obligations are satisfied. Determining the SSP for performance obligations requires significant judgment. In developing the SSP for a performance obligation, the Company considers applicable market conditions and relevant entity-specific factors, including factors that were contemplated in negotiating the agreement with the customer and estimated costs. In certain circumstances, the Company may apply the residual method to determine the SSP of a good or service if the standalone selling price is considered highly variable or uncertain. The Company validates the SSP for performance obligations by evaluating whether changes in the key assumptions used to determine the SSP will have a significant effect on the allocation of arrangement consideration between multiple performance obligations. If the consideration promised in a contract includes a variable amount, the Company estimates the amount of consideration to which it will be entitled in exchange for transferring the promised goods or services to a customer. The Company determines the amount of variable consideration by using the expected value method or the most likely amount method. The Company includes the unconstrained amount of estimated variable consideration in the transaction price. The amount included in the transaction price is constrained to the amount for which it is probable that a significant reversal of cumulative revenue recognized will not occur. At the end of each subsequent reporting period, the Company re-evaluates the estimated variable consideration included in the transaction price and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis in the period of adjustment. If an arrangement includes development and regulatory milestone payments, the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s control or the licensee’s control, such as regulatory approvals, are generally not considered probable of being achieved until those approvals are received. In determining the transaction price, the Company adjusts consideration for the effects of the time value of money if the timing of payments provides the Company with a significant benefit of financing. The Company does not assess whether a contract has a significant financing component if the expectation at contract inception is such that the period between payment by the licensees and the transfer of the promised goods or services to the licensees will be one year or less. The Company assessed its arrangements with Shionogi 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. For additional information, refer to Note 6, Collaboration Agreements . Product Revenue, Net The Company recognizes product revenue, net of variable consideration related to certain allowances and accruals that are determined using the expected value method, in its consolidated financial statements at the point in time when control transfers to the customer, which is typically when the product has been delivered to the customer’s location. The amount included in the transaction price is constrained to the amount for which it is probable that a significant reversal of cumulative revenue recognized will not occur. The Company’s only performance obligation identified for ZULRESSO is to deliver the product to the location specified by the customer’s order. The Company records shipping and handling costs associated with delivery of product to its customers within selling, general and administrative expenses on its consolidated statements of operations and comprehensive income (loss). The Company expenses incremental costs of obtaining a contract as incurred if the expected amortization period of the asset would be less than one year. If the Company were to incur incremental costs with an amortization period greater than a year, such costs would be capitalized as contract assets, as they are expected to be recovered, and would be expensed by amortizing on a systematic basis that is consistent with the transfer to the customer of the goods or services to which the asset relates. The Company did not have any contract assets (unbilled receivables) at December 31, 2022, as customer invoicing generally occurs before or at the time of revenue recognition. The Company did not have any contract liabilities at December 31, 2022, as the Company did not receive any payments in advance of satisfying its performance obligations to its customers. Amounts billed or invoiced that are considered trade accounts receivable are included in prepaid expenses and other current assets on the consolidated balance sheets. As of December 31, 2022 and 2021, the Company had not provided any allowance for bad debts against the trade accounts receivable, and the amount of trade accounts receivable was not significant. The Company records reserves, based on contractual terms, for the following components of variable consideration related to product sold during the reporting period, as well as its estimate of product that remains in the distribution channel inventory of its customers at the end of the reporting period. On a quarterly basis, the Company updates its estimates, if necessary, and records any material adjustments in the period they are identified. Chargebacks : The Company estimates chargebacks from its customers who directly purchase the product from the Company for discounts resulting from contractual commitments to sell products to eligible healthcare settings at prices lower than the list prices charged to its customers. Customers charge the Company for the difference between what they pay to the Company for the product and the selling price to the eligible healthcare settings. Reserves for chargebacks consist of credits that the Company expects to issue for units that remain in the distribution channel inventories at the end of each reporting period that the Company expects will be sold to eligible healthcare settings, and chargebacks that customers have claimed, but for which the Company has not yet issued a credit. Government Rebates : The Company is subject to discount obligations under government programs, including Medicaid. The Company records reserves for rebates in the same period the related product revenue is recognized, resulting in a reduction of ZULRESSO product revenue and a current liability that is included in accrued expenses on its consolidated balance sheets. The Company’s liability for these rebates consists of invoices received for claims from prior quarters that have not been paid or for which an invoice has not yet been received, estimates of claims for the current quarter, and estimates of future claims that will be made for product that has been recognized as revenue, but which remains in the distribution channel at the end of each reporting period. Trade Discounts and Allowances : The Company generally provides customary invoice discounts on ZULRESSO sales to its customers for prompt payment and the Company pays fees for sales order management, data, and distribution services. The Company estimates its customers will earn these discounts and fees and deducts these discounts and fees in full from gross ZULRESSO revenue and accounts receivable at the time the Company recognizes the related revenue. Financial Assistance : The Company provides voluntary financial assistance programs to patients with commercial insurance that have coverage and reside in states that allow financial assistance. The Company estimates the financial assistance amounts for ZULRESSO and records any such amounts within accrued expenses on its consolidated balance sheets. The calculation of the accrual for financial assistance is based on an estimate of claims and the cost per claim that the Company expects to receive using demographics for patients who have registered and been approved for assistance. Any adjustments are recorded in the same period the related revenue is recognized, resulting in a reduction of product revenue and the establishment of a current liability, which is included as a component of accrued expenses on the consolidated balance sheets. Product Returns : Consistent with industry practice, the Company offers product return rights to customers for damaged, defective or expiring product, provided it is within a specified period around the product expiration date as set forth in the Company’s return goods policy. The Company estimates the amount of its product sales that may be returned by its customers and records this estimate as a reduction of revenue in the period the related product revenue is recognized, as well as a reserve within accrued expenses on the consolidated balance sheets. Product returns have been not significant to date and are not expected to be significant in the future.
Collaborative Arrangements	Collaborative Arrangements The Company analyzes its collaboration arrangements to assess whether such arrangements involve joint operating activities performed by parties that are both active participants in the activities and exposed to significant risks and rewards dependent on the commercial success of such activities and therefore within the scope of ASC Topic 808, Collaborative Arrangements (“Topic 808”). This assessment is performed throughout the life of the arrangement based on changes in the responsibilities of all parties in the arrangement. For collaboration arrangements within the scope of Topic 808 that contain multiple elements, the Company first determines which elements of the collaboration are deemed to be within the scope of Topic 808 and which elements of the collaboration are more reflective of a vendor-customer relationship and therefore within the scope of Topic 606. For elements of collaboration arrangements that are accounted for pursuant to Topic 808, an appropriate recognition method is determined and applied consistently, either by analogy to authoritative accounting literature or by applying a reasonable and rational policy election. For those elements of the arrangement that are accounted for pursuant to Topic 606, the Company applies the five-step model described above, and presents the arrangement as collaboration revenue in the consolidated statements of operations and comprehensive income (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 customer relationship, such as co-development and co-commercialization activities, are recorded as research and development expense or selling, general and administrative expense, in the event of a payment to the collaborative partner in a period, or a reduction to these expense line items in the event of a reimbursement from the collaboration partner in a period, as appropriate.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. This standard enhances and simplifies various aspects of the income tax accounting guidance in ASC Topic 740, Income Taxes , including requirements related to hybrid tax regimes, the tax basis step-up in goodwill obtained in a transaction that is not a business combination, separate financial statements of entities not subject to tax, the intra-period tax allocation exception to the incremental approach, ownership changes in investments, changes from a subsidiary to an equity method investment, interim-period accounting for enacted changes in tax law, and the year-to-date loss limitation in interim-period tax accounting. The Company adopted the standard on the required effective date of January 1, 2021. This guidance did not have a significant impact on the Company’s consolidated financial statements and related disclosures. Other accounting standards that have been issued or proposed by the FASB or other standards-setting bodies that do not require adoption until a future date are not expected to have a material impact on the Company’s consolidated financial statements upon adoption.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Summary of Company's Cash Equivalents and Marketable Securities	The following tables summarize the Company’s cash equivalents and marketable securities as of December 31, 2022 and 2021: December 31, 2022 Total Quoted Significant Significant (in thousands) Cash equivalents: Money market funds $ 161,185 $ 161,185 $ — $ — Total cash equivalents 161,185 161,185 — — Marketable securities: U.S. government securities 302,911 — 302,911 — U.S. corporate bonds 354,495 — 354,495 — International corporate bonds 127,248 — 127,248 — U.S. commercial paper 63,114 — 63,114 — International commercial paper 133,163 — 133,163 — U.S. certificates of deposit 15,613 — 15,613 — U.S. municipal securities 113,250 — 113,250 — Total marketable securities 1,109,794 — 1,109,794 — $ 1,270,979 $ 161,185 $ 1,109,794 $ — December 31, 2021 Total Quoted Significant Significant (in thousands) Cash equivalents: Money market funds $ 289,440 $ 289,440 $ — $ — U.S. commercial paper 2,000 — 2,000 — International commercial paper 1,999 — 1,999 — Total cash equivalents 293,439 289,440 3,999 — Marketable securities: U.S. government securities 324,532 — 324,532 — U.S. corporate bonds 627,780 — 627,780 — International corporate bonds 236,812 — 236,812 — U.S. commercial paper 80,176 — 80,176 — International commercial paper 142,335 — 142,335 — U.S. municipal securities 36,428 — 36,428 — Total marketable securities 1,448,063 — 1,448,063 — $ 1,741,502 $ 289,440 $ 1,452,062 $ —
Summary of Gross Unrealized Gains and Losses of Marketable Securities	The following tables summarize the gross unrealized gains and losses of the Company’s marketable securities as of December 31, 2022 and 2021: December 31, 2022 Amortized Gross Unrealized Gross Unrealized Credit Losses Fair Value (in thousands) Assets: U.S. government securities $ 307,173 $ — $ ( 4,262 ) $ — $ 302,911 U.S. corporate bonds 358,019 6 ( 3,530 ) — 354,495 International corporate bonds 128,374 7 ( 1,133 ) — 127,248 U.S. commercial paper 63,234 — ( 120 ) — 63,114 International commercial paper 133,338 — ( 175 ) — 133,163 U.S. certificates of deposit 15,613 — — — 15,613 U.S. municipal securities 114,249 31 ( 1,030 ) — 113,250 $ 1,120,000 $ 44 $ ( 10,250 ) $ — $ 1,109,794 December 31, 2021 Amortized Gross Unrealized Gross Unrealized Credit Losses Fair Value (in thousands) Assets: U.S. government securities $ 325,514 $ — $ ( 982 ) $ — $ 324,532 U.S. corporate bonds 628,836 27 ( 1,083 ) — 627,780 International corporate bonds 237,303 — ( 491 ) — 236,812 U.S. commercial paper 80,194 — ( 18 ) — 80,176 International commercial paper 142,358 — ( 23 ) — 142,335 U.S. municipal securities 36,518 — ( 90 ) — 36,428 $ 1,450,723 $ 27 $ ( 2,687 ) $ — $ 1,448,063
Summary of Fair Value And Unrealized Losses of Marketable Securities In Loss Position	The following tables summarize the fair value and the unrealized losses of the Company’s marketable securities that have been in a loss position for either less than twelve months or greater than twelve months as of December 31, 2022 and 2021: December 31, 2022 Less than 12 months Greater than 12 months Total Fair Unrealized Fair Unrealized Fair Unrealized (in thousands) U.S. government securities $ 112,243 $ ( 1,517 ) $ 185,691 $ ( 2,745 ) 297,934 $ ( 4,262 ) U.S. corporate bonds 208,507 ( 1,989 ) 130,633 ( 1,541 ) 339,140 ( 3,530 ) International corporate bonds 50,982 ( 497 ) 68,993 ( 636 ) 119,975 ( 1,133 ) U.S. commercial paper 24,768 ( 120 ) — — 24,768 ( 120 ) International commercial paper 30,987 ( 175 ) — — 30,987 ( 175 ) U.S. municipal securities 86,251 ( 497 ) 14,466 ( 533 ) 100,717 ( 1,030 ) $ 513,738 $ ( 4,795 ) $ 399,783 $ ( 5,455 ) $ 913,521 $ ( 10,250 ) December 31, 2021 Less than 12 months Greater than 12 months Total Fair Unrealized Fair Unrealized Fair Unrealized (in thousands) U.S. government securities $ 309,588 $ ( 982 ) $ — $ — $ 309,588 $ ( 982 ) U.S. corporate bonds 601,475 ( 1,083 ) — — 601,475 ( 1,083 ) International corporate bonds 231,672 ( 491 ) — — 231,672 ( 491 ) U.S. commercial paper 21,968 ( 18 ) — — 21,968 ( 18 ) International commercial paper 35,059 ( 23 ) — — 35,059 ( 23 ) U.S. municipal securities 24,953 ( 90 ) — — 24,953 ( 90 ) $ 1,224,715 $ ( 2,687 ) $ — $ — $ 1,224,715 $ ( 2,687 )

Balance Sheet Components (Table

Balance Sheet Components (Tables)	12 Months Ended
	Dec. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Summary of Property and Equipment, Net	The following table summarizes property and equipment, net, as of December 31, 2022 and 2021: December 31, December 31, 2022 2021 (in thousands) Computer hardware and software $ 1,771 $ 1,391 Furniture and equipment 1,714 1,208 Leasehold improvements 5,508 5,390 8,993 7,989 Less: Accumulated depreciation ( 6,095 ) ( 4,973 ) $ 2,898 $ 3,016
Summary of Accrued Expenses	The following tables summarizes accrued expenses as of December 31, 2022 and 2021: December 31, December 31, 2022 2021 (in thousands) Accrued research and development costs $ 32,565 $ 39,147 Employee-related 29,372 18,618 Professional services 10,172 8,893 Other 557 617 $ 72,666 $ 67,275

Leases, Commitments and Conti_2

Leases, Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Schedule of Amount of Operating Leases	The following table shows the amounts of operating leases in the balance sheets as of December 31, 2022 and 2021: December 31, Balance sheet location Balance sheet caption 2022 2021 (in thousands) Assets Right-of-use operating asset Right-of-use operating asset $ 10,532 $ 16,109 Liabilities Current operating lease Operating lease liability, current portion 7,643 7,468 Long-term operating lease Operating lease liability, net of current portion 4,491 10,964 $ 12,134 $ 18,432
Schedule of Lease Expense by Lease Type Recognized	The following table shows the amounts of lease expense by lease type that was recognized during the years ended December 31, 2022, 2021 and 2020: Year Ended December 31, 2022 2021 2020 (in thousands) Operating lease cost $ 6,748 $ 8,748 $ 8,838 Variable lease cost 1,846 1,600 2,285 Short-term lease cost 206 101 74 Sublease income ( 421 ) ( 234 ) - $ 8,379 $ 10,215 $ 11,197
Schedule of Minimum Lease Payments	The minimum lease payments are expected to be as follows: Years Ending December 31, (In thousands) 2023 $ 7,643 2024 5,316 Thereafter - Total lease payments 12,959 Less imputed interest ( 825 ) Present value of operating lease liabilities $ 12,134
Schedule of Weighted Average Remaining Lease Term and Weighted Average Discount Rate of Our Operating Leases	The following table shows the weighted average remaining lease term and weighted average discount rate of the operating leases: Year ended December 31, 2022 2021 Weighted average remaining lease term in years 1.68 2.68 Weighted average discount rate 7.5 % 7.5 %
Schedule of Supplemental Disclosure of Cash Flow Information Related to Operating Leases	The following table shows the supplemental disclosure of cash flow information related to the operating leases included in cash flows used by operating activities in the consolidated statements of cash flows: Year Ended December 31, 2022 2021 2020 (in thousands) Cash paid for amounts included in $ 7,468 $ 9,264 $ 9,231 Lease asset de-recognized upon lease Operating leases $ — $ 3,733 $ 2,310

Collaboration Agreements (Table

Collaboration Agreements (Tables)	12 Months Ended
	Dec. 31, 2022
Collaboration Agreement [Abstract]
Summary of Operating Expenses Category Related to Collaboration Agreement	The following table summarizes expenses related to the Biogen Collaboration Agreement that were incurred by the Company and the related reimbursement from Biogen, reflected by category of operating expenses: Year Ended December 31, 2022 2021 (in thousands) Expenses related to the Biogen Collaboration Agreement $ 213,524 $ 193,776 Net reimbursement from Biogen reflected in the Research and development expenses ( 73,227 ) ( 79,848 ) Selling, general and administrative expenses ( 2,230 ) ( 11,282 ) ( 75,457 ) ( 91,130 ) Total net expenses related to the Biogen Collaboration $ 138,067 $ 102,646

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2022
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, 2021 1,256,098 $ 57.87 Granted 705,380 40.02 Vested ( 366,014 ) 40.13 Forfeited ( 179,983 ) 95.84 Outstanding as of December 31, 2022 1,415,481 48.73
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, 2021 7,283,439 $ 84.17 6.74 $ 16,590 Granted 1,181,487 $ 39.45 Exercised ( 156,195 ) $ 7.84 Forfeited ( 520,381 ) $ 98.65 Outstanding as of December 31, 2022 7,788,350 $ 77.95 6.36 $ 7,275 Vested and expected to vest as of December 31, 2022 6,724,505 $ 78.86 6.05 $ 6,917 Exercisable as of December 31, 2022 5,109,027 $ 85.76 5.22 $ 5,607
Summary of Stock-Based Compensation Expense Recognized	The following table summarizes stock-based compensation expense recognized during the years ended December 31, 2022, 2021 and 2020: Year Ended December 31, 2022 2021 2020 (in thousands) Research and development $ 25,888 $ 49,746 $ 42,370 Selling, general and administrative 35,714 54,883 51,836 Restructuring — — 1,788 $ 61,602 $ 104,629 $ 95,994
Summary of Stock-Based Compensation Expense by Award Type	The following table summarizes stock-based compensation expense by award type recognized during the years ended December 31, 2022, 2021 and 2020: Year Ended December 31, 2022 2021 2020 (in thousands) Stock options $ 54,971 $ 78,516 $ 90,064 Restricted stock units 5,587 25,375 4,904 Employee stock purchase plan 1,044 738 1,026 $ 61,602 $ 104,629 $ 95,994
Summary of Weighted Average Assumptions Used to Compute Fair Value of Option Granted	The fair value of each stock option granted under the Company’s equity plans has been calculated on the date of grant using the following weighted average assumptions: Year Ended December 31, 2022 2021 2020 Expected dividend yield 0 % 0 % 0 % Expected volatility 73 % 76 % 78 % Risk-free interest rate 2.49 % 0.63 % 0.97 % Expected term 6.03 years 5.92 years 5.98 years

Net Income (Loss) Per Share (Ta

Net Income (Loss) Per Share (Tables)	12 Months Ended
	Dec. 31, 2022
Earnings Per Share [Abstract]
Summary of Basic and Diluted Net Income (Loss) Per Share	The following table shows the calculation of basic and diluted net income (loss) per share for the years ended December 31, 2022, 2021 and 2020: Year Ended December 31, 2022 2021 2020 Basic net income (loss) per share: Numerator: Net income (loss) (in thousands) $ ( 532,784 ) $ ( 457,892 ) $ 606,073 Denominator: Weighted average common stock outstanding 59,306,094 58,670,230 51,983,188 Effect of dilutive securities: Stock options — — 721,791 Restricted stock units — — 292,241 Employee Stock Purchase Plan — — 5,895 Total dilutive securities — — 1,019,927 Weighted average common stock outstanding 59,306,094 58,670,230 53,003,115 Net income (loss) per share—basic $ ( 8.98 ) $ ( 7.80 ) $ 11.66 Net income (loss) per share—diluted $ ( 8.98 ) $ ( 7.80 ) $ 11.43
Summary of Anti-Dilutive Common Stock Equivalents Outstanding	The following table summarizes common stock equivalents outstanding that were excluded from the calculation of diluted net loss per share because including them would have been anti-dilutive as of December 31, 2022, 2021 and 2020: Year Ended December 31, 2022 2021 2020 Stock options 7,138,350 6,599,429 4,781,737 Restricted stock units 160,403 563,334 — Employee stock purchase plan 76,105 23,625 — 7,374,858 7,186,388 4,781,737

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Summary of Income (Loss) Before Income Tax Expense	Income (loss) before income tax expense consists of the following: Year Ended December 31, 2022 2021 2020 (in thousands) Domestic $ ( 532,539 ) $ ( 457,693 ) $ 639,986 Foreign ( 245 ) ( 199 ) ( 33,913 ) $ ( 532,784 ) $ ( 457,892 ) $ 606,073
Summary of Reconciliation of U.S. Statutory Rate to Company's Effective Tax Rate	A reconciliation of the U.S. statutory rate to the Company’s effective tax rate is as follows: Year Ended December 31, 2022 2021 2020 Tax due at statutory rate 21.0 % 21.0 % 21.0 % State taxes, net of federal 1.8 1.9 5.7 Biogen transaction-related items — — ( 10.1 ) Stock-based compensation ( 1.9 ) ( 5.2 ) 0.9 Foreign rate differential — — 1.2 Federal and state tax credits 2.1 3.5 ( 1.5 ) Change in valuation allowance ( 23.0 ) ( 20.7 ) ( 17.6 ) Other — ( 0.5 ) 0.4 0.0 % 0.0 % 0.0 %
Summary of Significant Components of Company's Net Deferred Tax Asset	Significant components of the Company’s net deferred tax assets at December 31, 2022 and 2021 are as follows: December 31, 2022 2021 (in thousands) Net operating losses $ 347,880 $ 305,824 Tax credits 118,393 106,176 Capitalized research and development expenses 66,849 — Stock-based compensation 49,916 49,281 Accrued expenses 8,750 6,684 Depreciation and amortization 1,386 1,401 Right of use asset ( 2,433 ) ( 3,702 ) Lease liability 2,803 4,236 Other ( 258 ) 704 Total net deferred tax asset before valuation 593,286 470,604 Valuation allowance ( 593,286 ) ( 470,604 ) $ — $ —
Summary of Gross Unrecognized Tax Benefits Excluding Interest and Penalties	The following table reconciles the beginning and ending amounts of gross unrecognized tax benefits, excluding interest and penalties, if any, for the years ended December 31, 2022 and 2021: 2022 2021 (in thousands) Balance as of January 1 $ 6,084 $ - Increases related to current year tax positions 697 396 Increases related to prior year tax positions 65 5,688 Balance as of December 31 $ 6,846 $ 6,084

Nature of the Business - Additi

Nature of the Business - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended		153 Months Ended
	Dec. 31, 2022	Dec. 31, 2020	Dec. 31, 2022	Dec. 31, 2021
Nature Of Business [Line Items]
Net income from up-front		$ 606,100
Up-front payments receive	$ 1,000,000
Accumulated deficit	$ 2,028,170		$ 2,028,170	$ 1,495,386
Redeemable Convertible Preferred Stock [Member] | Convertible Notes [Member] | Initial Public Offering [Member]
Nature Of Business [Line Items]
Net proceeds from sale of equity and notes			$ 2,800,000

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Summary Of Significant Accounting Policies [Line Items]
Expected dividend yield	0%	0%	0%
Prepaid Expenses and Other Current Assets [Member]
Summary Of Significant Accounting Policies [Line Items]
Trade accounts receivables	$ 1.5	$ 1.1
Inventory	$ 1.7	$ 1.4
Product Revenue [Member]
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	Dec. 31, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	$ 161,185	$ 293,439
Total marketable securities	1,109,794	1,448,063
Total cash equivalents and marketable securities	1,270,979	1,741,502
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	161,185	289,440
Total cash equivalents and marketable securities	161,185	289,440
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents		3,999
Total marketable securities	1,109,794	1,448,063
Total cash equivalents and marketable securities	1,109,794	1,452,062
Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	161,185	289,440
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	161,185	289,440
International Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	127,248	236,812
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	127,248	236,812
U.S. Government Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	302,911	324,532
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 marketable securities	302,911	324,532
U.S. Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	354,495	627,780
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	354,495	627,780
U.S. Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents		2,000
Total marketable securities	63,114	80,176
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		2,000
Total marketable securities	63,114	80,176
International Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents		1,999
Total marketable securities	133,163	142,335
International 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		1,999
Total marketable securities	133,163	142,335
U.S. Certificates of Deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	15,613
U.S. Certificates of Deposit [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	15,613
U.S. Municipal Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total marketable securities	113,250	36,428
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	$ 113,250	$ 36,428

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Debt Instrument Fair Value Carrying Value [Line Items]
Transfers among the Level 1, Level 2 and Level 3 categories	$ 0	$ 0
Impairment of assets	0	0
US Treasury Bond Securities | Corporate Bonds and Municipal Securities [Member]
Debt Instrument Fair Value Carrying Value [Line Items]
Marketable securities fair value held to maturity	$ 211,200,000	$ 436,100,000
Maximum [Member] | US Treasury Bond Securities | U.S. Corporate Bonds [Member]
Debt Instrument Fair Value Carrying Value [Line Items]
Marketable securities, remaining contractual maturities	1 year	1 year
Maximum [Member] | US Treasury Bond Securities | Corporate Bonds and Municipal Securities [Member]
Debt Instrument Fair Value Carrying Value [Line Items]
Marketable securities held, matuirity period	2 years	2 years
Minimum [Member] | US Treasury Bond Securities | Corporate Bonds and Municipal Securities [Member]
Debt Instrument Fair Value Carrying Value [Line Items]
Marketable securities held, matuirity period	1 year	1 year

Fair Value Measurements - Sum_2

Fair Value Measurements - Summary of Gross Unrealized Gains and Losses of Marketable Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 1,120,000	$ 1,450,723
Gross Unrealized Gains	44	27
Gross Unrealized Losses	(10,250)	(2,687)
Fair Value	1,109,794	1,448,063
U.S. Government Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	307,173	325,514
Gross Unrealized Losses	(4,262)	(982)
Fair Value	302,911	324,532
U.S. Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	358,019	628,836
Gross Unrealized Gains	6	27
Gross Unrealized Losses	(3,530)	(1,083)
Fair Value	354,495	627,780
International Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	128,374	237,303
Gross Unrealized Gains	7
Gross Unrealized Losses	(1,133)	(491)
Fair Value	127,248	236,812
U.S. Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	63,234	80,194
Gross Unrealized Losses	(120)	(18)
Fair Value	63,114	80,176
International Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	133,338	142,358
Gross Unrealized Losses	(175)	(23)
Fair Value	133,163	142,335
U.S. Certificates of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	15,613
Fair Value	15,613
U.S. Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	114,249	36,518
Gross Unrealized Gains	31
Gross Unrealized Losses	(1,030)	(90)
Fair Value	$ 113,250	$ 36,428

Fair Value Measurements - Sum_3

Fair Value Measurements - Summary of Fair Value And Unrealized Losses of Marketable Securities In Loss Position (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	$ 513,738	$ 1,224,715
Less than 12 months, Unrealized Losses	(4,795)	(2,687)
Greater than 12 months, Fair Value	399,783
Greater than 12 months, Unrealized Losses	(5,455)
Fair Value	913,521	1,224,715
Unrealized Losses	(10,250)	(2,687)
U.S. Government Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	112,243	309,588
Less than 12 months, Unrealized Losses	(1,517)	(982)
Greater than 12 months, Fair Value	185,691
Greater than 12 months, Unrealized Losses	(2,745)
Fair Value	297,934	309,588
Unrealized Losses	(4,262)	(982)
U.S. Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	208,507	601,475
Less than 12 months, Unrealized Losses	(1,989)	(1,083)
Greater than 12 months, Fair Value	130,633
Greater than 12 months, Unrealized Losses	(1,541)
Fair Value	339,140	601,475
Unrealized Losses	(3,530)	(1,083)
International Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	50,982	231,672
Less than 12 months, Unrealized Losses	(497)	(491)
Greater than 12 months, Fair Value	68,993
Greater than 12 months, Unrealized Losses	(636)
Fair Value	119,975	231,672
Unrealized Losses	(1,133)	(491)
U.S. Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	24,768	21,968
Less than 12 months, Unrealized Losses	(120)	(18)
Fair Value	24,768	21,968
Unrealized Losses	(120)	(18)
International Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	30,987	35,059
Less than 12 months, Unrealized Losses	(175)	(23)
Fair Value	30,987	35,059
Unrealized Losses	(175)	(23)
U.S. Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	86,251	24,953
Less than 12 months, Unrealized Losses	(497)	(90)
Greater than 12 months, Fair Value	14,466
Greater than 12 months, Unrealized Losses	(533)
Fair Value	100,717	24,953
Unrealized Losses	$ (1,030)	$ (90)

Balance Sheet Components - Summ

Balance Sheet Components - Summary of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 8,993	$ 7,989
Less: Accumulated depreciation	(6,095)	(4,973)
Property and equipment, net	2,898	3,016
Computer Hardware and Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,771	1,391
Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,714	1,208
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 5,508	$ 5,390

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 1,122	$ 4,182	$ 2,630
Computer Hardware and Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	3 years
Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	5 years

Balance Sheet Components - Su_2

Balance Sheet Components - Summary of Accrued Expenses (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Payables and Accruals [Abstract]
Accrued research and development costs	$ 32,565	$ 39,147
Employee-related	29,372	18,618
Professional services	10,172	8,893
Other	557	617
Total accrued expenses	$ 72,666	$ 67,275

Leases, Commitments and Conti_3

Leases, Commitments and Contingencies - Operating Leases - Additional Information (Detail) $ in Thousands		12 Months Ended
	Jan. 01, 2020 ft²	Dec. 31, 2022 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2021 USD ($)	Dec. 13, 2021 USD ($)	Jan. 01, 2019 USD ($)
Commitments And Contingencies [Line Items]
Lease expire date			Jan. 31, 2022
Operating lease option to extend		true
Operating lease renewal term		5 years
Right-of-use operating asset | $		$ 10,532		$ 16,109	$ 3,700	$ 5,300
Lessee, operating lease contract term			3 years
Remaining Amount Of Lease Write Off | $			$ 2,300
Restricted Cash And Cash Equivalents Noncurrent | $			$ 700
Operating Lease One [Member]
Commitments And Contingencies [Line Items]
Office space rent under operating lease	63,017
Lease expire date	Aug. 31, 2024
Operating Lease Two [Member]
Commitments And Contingencies [Line Items]
Office space rent under operating lease	40,419
Lease expire date	Aug. 31, 2024
Operating Lease Three [Member]
Commitments And Contingencies [Line Items]
Office space rent under operating lease	15,525
Lease expire date	Nov. 30, 2024
Operating Lease Five [Member]
Commitments And Contingencies [Line Items]
Office space rent under operating lease	15,975
Lease expire date	Feb. 29, 2024
Minimum [Member]
Commitments And Contingencies [Line Items]
Operating lease remaining lease terms		1 year
Maximum [Member]
Commitments And Contingencies [Line Items]
Operating lease remaining lease terms		2 years

Leases, Commitments and Conti_4

Leases, Commitments and Contingencies - Schedule of Amounts of Operating Leases (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 13, 2021	Jan. 01, 2019
Assets
Right-of-use operating asset	$ 10,532	$ 16,109	$ 3,700	$ 5,300
Liabilities
Current operating lease liabilities	7,643	7,468
Long-term operating lease liabilities	4,491	10,964
Total operating lease liabilities	$ 12,134	$ 18,432

Leases, Commitments and Conti_5

Leases, Commitments and Contingencies - Schedule of Lease Expense by Lease Type Recognized (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Operating lease cost	$ 6,748	$ 8,748	$ 8,838
Variable lease cost	1,846	1,600	2,285
Short-term lease cost	206	101	74
Sublease income	(421)	(234)
Total	$ 8,379	$ 10,215	$ 11,197

Leases, Commitments and Conti_6

Leases, Commitments and Contingencies - Schedule of Minimum Lease Payments (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Lessee Lease Description [Line Items]
Present value of operating lease liabilities	$ 12,134	$ 18,432
ASU Topic (842) [Member]
Lessee Lease Description [Line Items]
2023	7,643
2024	5,316
Total lease payments	12,959
Less imputed interest	(825)
Present value of operating lease liabilities	$ 12,134

Leases, Commitments and Conti_7

Leases, Commitments and Contingencies - Schedule of Weighted Average Remaining Lease Term and Weighted Average Discount Rate of Our Operating Leases (Detail)	Dec. 31, 2022	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Weighted average remaining lease term in years	1 year 8 months 4 days	2 years 8 months 4 days
Weighted average discount rate	7.50%	7.50%

Leases, Commitments and Conti_8

Leases, Commitments and Contingencies - Schedule of Supplemental Disclosure of Cash Flow Information Related To Operating Leases (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Cash paid for amounts included in the measurement of lease liabilities	$ 7,468	$ 9,264	$ 9,231
Lease asset de-recognized upon lease cancellation		$ 3,733	$ 2,310

Leases, Commitments and Conti_9

Leases, Commitments and Contingencies - CyDex License Agreement - Additional Information (Detail) - USD ($)	12 Months Ended			88 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2022
Commitments And Contingencies [Line Items]
Research and development expense	$ 326,163,000	$ 283,166,000	$ 292,714,000
CyDex License Agreement [Member]
Commitments And Contingencies [Line Items]
Research and development expense				$ 1,000,000
CyDex License Agreement [Member] | First and Second Clinical Development Milestones [Member] | Brexanolone [Member] | Maximum [Member]
Commitments And Contingencies [Line Items]
Expected milestone payments	800,000			800,000
CyDex License Agreement [Member] | First and Second Regulatory Milestones [Member] | Brexanolone [Member] | Maximum [Member]
Commitments And Contingencies [Line Items]
Expected milestone payments	3,800,000			3,800,000
CyDex License Agreement [Member] | Third and Fourth Clinical Development Milestones [Member] | Brexanolone [Member] | Maximum [Member]
Commitments And Contingencies [Line Items]
Expected milestone payments	1,300,000			1,300,000
CyDex License Agreement [Member] | Third and Fourth Regulatory Milestones [Member] | Brexanolone [Member] | Maximum [Member]
Commitments And Contingencies [Line Items]
Expected milestone payments	8,500,000			8,500,000
CyDex License Agreement [Member] | Clinical Development [Member] | SAGE-689 [Member]
Commitments And Contingencies [Line Items]
Research and development expense		100,000	$ 1,300,000
CyDex License Agreement [Member] | Clinical Development [Member] | SAGE-689 [Member] | Maximum [Member]
Commitments And Contingencies [Line Items]
Expected milestone payments	800,000			800,000
CyDex License Agreement [Member] | Regulatory Milestones [Member]
Commitments And Contingencies [Line Items]
Construction Expense Related To Milestone Payment		$ 1,300,000
CyDex License Agreement [Member] | Regulatory Milestones [Member] | SAGE-689 [Member] | Maximum [Member]
Commitments And Contingencies [Line Items]
Expected milestone payments	1,800,000			1,800,000
CyDex License Agreement [Member] | Clinical Development and Regulatory Milestones [Member]
Commitments And Contingencies [Line Items]
Research and development expense related to milestone expense				3,600,000
Milestone payments				3,600,000
Intangible asset related to milestone	$ 3,000,000			$ 3,000,000

Leases, Commitments and Cont_10

Leases, Commitments and Contingencies - University of California License Agreements - Additional Information (Detail) - University of California License Agreements [Member] - USD ($)		1 Months Ended	12 Months Ended				88 Months Ended
	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2015	Dec. 31, 2022
Commitments And Contingencies [Line Items]
Upfront payment		$ 50,000
Annual license maintenance fee						$ 15,000
Milestone payments			$ 0	$ 0	$ 0
After The Effective Date [Member]
Commitments And Contingencies [Line Items]
Licenses Expiration period, maximum	27 years
After The First Sale [Member]
Commitments And Contingencies [Line Items]
Licenses Expiration period, maximum	15 years
Clinical Development [Member]
Commitments And Contingencies [Line Items]
Milestone payments	$ 100,000
Milestone outstanding	$ 0
Clinical Development [Member] | Maximum [Member]
Commitments And Contingencies [Line Items]
Percentage of net sales paid as royalties	1%
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
Milestone payments related to intangible assets							$ 500,000

Collaboration Agreements - Addi

Collaboration Agreements - Additional Information (Detail) - USD ($)			3 Months Ended		9 Months Ended	12 Months Ended
	Nov. 30, 2020	Jun. 30, 2018	Dec. 31, 2021	Jun. 30, 2018	Sep. 30, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Jun. 12, 2018
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue						$ 7,686,000	$ 6,308,000	$ 1,114,200,000
Public offering of common stock, net of offering costs, Shares								6,241,473
Collaboration receivable - related party			$ 18,506,000			13,660,000	18,506,000
Shionogi Collaboration Agreement [Member] | Collaboration Revenue [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue						0	0	$ 0
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						0	0	1,100,000,000
Standalone selling price of license performance obligation								1,100,000,000
Sale of stock, consideration received								$ 1,500,000,000
Public offering of common stock, net of offering costs, Shares								6,241,473
Purchase price								$ 650,000,000
Operating expenses						75,457,000	$ 91,130,000
Proceeds from related parties			$ 80,300,000		$ 80,300,000
Collaboration receivable - related party						13,700,000
Payments To Related Parties						$ 0
Biogen Collaboration Agreement [Member] | SAGE-217 [Member] | Maximum [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Additional milestone payment receivable									$ 1,600,000,000
Biogen Collaboration Agreement [Member] | SAGE-217 [Member] | Maximum [Member] | First Commercial Sale of Zuranolone [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Future milestone payments	$ 225,000,000
Biogen Collaboration Agreement [Member] | SAGE-217 [Member] | Maximum [Member] | Sales Milestones [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Future milestone payments	300,000,000
Biogen Collaboration Agreement [Member] | SAGE-217 [Member] | Maximum [Member] | Regulatory and Commercial Milestones [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Future milestone payments	475,000,000
Biogen Collaboration Agreement [Member] | SAGE-324 [Member] | Maximum [Member] | Sales Milestones [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Future milestone payments	300,000,000
Biogen Collaboration Agreement [Member] | SAGE-324 [Member] | Maximum [Member] | Regulatory and Commercial Milestones [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Future milestone payments	$ 520,000,000
Biogen Stock Purchase Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment								875,000,000
Purchase price								650,000,000
Transaction price, total								1,100,000,000
Premium amount on equity investment								$ 232,500,000
Price per share								$ 104.14
Premium on per share price								40%
Biogen stock purchase agreement, description						The standstill restrictions 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. BIMA also agreed not to, and to cause its affiliates not to, sell or transfer any of the Biogen Shares for a period of eighteen months from the closing of the sale of the Biogen Shares, which period expired on June 30, 2022, and to limit sales and transfers of the Biogen Shares for an additional eighteen-month period, in each case subject to specified conditions and exceptions.
Stock issued								$ 417,500,000

Collaboration Agreements - Summ

Collaboration Agreements - Summary of Operating Expenses Category Related to Collaboration Agreement (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Net reimbursement from Biogen reflected in the consolidated statements of operations and comprehensive income (loss):
Total operating costs and expenses	$ 554,675	$ 467,217	$ 517,974
Biogen Collaboration Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Expenses related to the Biogen Collaboration Agreement incurred by Sage	213,524	193,776
Net reimbursement from Biogen reflected in the consolidated statements of operations and comprehensive income (loss):
Selling, general and administrative expenses	(2,230)	(11,282)
Operating expenses	(75,457)	(91,130)
Total operating costs and expenses	138,067	102,646
Research and Development [Member] | Biogen Collaboration Agreement [Member]
Net reimbursement from Biogen reflected in the consolidated statements of operations and comprehensive income (loss):
Research and development expenses	$ (73,227)	$ (79,848)

Preferred Stock - Additional In

Preferred Stock - Additional Information (Detail) - shares	Dec. 31, 2022	Dec. 31, 2021
Temporary Equity Disclosure [Abstract]
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0

Common Stock - Additional Infor

Common Stock - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Equity [Abstract]
Common stock, shares authorized	120,000,000	120,000,000
Common stock, par value	$ 0.0001	$ 0.0001
Dividends declared	$ 0	$ 0
Voting rights	Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders.
Public offering of common stock, net of offering costs, Shares			6,241,473
Common stock price per share			$ 104.14
Proceeds from public offering of common stock, net of commissions and underwriting discounts and offering costs			$ 650,000,000
Purchase of treasury stock, Shares	3,033
Total cost of shares held in treasury	$ 400,000	$ 400,000

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail)		12 Months Ended
	Jan. 01, 2022 shares	Dec. 31, 2022 USD ($) Milestone $ / shares shares	Dec. 31, 2021 USD ($) Milestone $ / shares shares	Dec. 31, 2020 USD ($) Milestone $ / shares shares	Dec. 31, 2019	Jun. 16, 2022 shares	Sep. 20, 2018 shares	Jul. 02, 2014 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation granted under plan vested period		4 years
Share based compensation, vest period		1 year
Share based compensation, term of plan		10 years
Total number of shares outstanding		9,203,831
Common stock available for issuance under stock option plan		7,086,615
Stock-based compensation expense | $		$ 61,602,000	$ 104,629,000	$ 95,994,000
Weighted average grant date fair value per share | $ / shares		$ 25.96	$ 51.87	$ 37.53
Share option, weighted-average forfeiture rates		19.20%	16.70%	20.60%
Performance Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding and unvested restricted stock units		1,255,078
Total unrecognized stock-based compensation expense | $		$ 62,400,000
Restricted stock units granted		705,380	531,176	471,386
Fair value of restricted stock units vested | $		$ 0		$ 0
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding and unvested restricted stock units		1,415,481	1,256,098
Restricted stock units granted		705,380
Stock-based compensation expense | $		$ 5,587,000	$ 25,375,000	4,904,000
Performance-Based Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense | $		$ 0	$ 0	0
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted		1,181,487
Total number of shares outstanding		7,788,350	7,283,439
Total unrecognized stock-based compensation expense | $		$ 61,000,000
Stock-based compensation expense | $		$ 54,971,000	$ 78,516,000	90,064,000
Weighted average period of unrecognized compensation costs		2 years 11 months 8 days
Intrinsic value of options exercised | $		$ 4,400,000	$ 9,000,000	$ 2,100,000
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted		0		0
Total unrecognized stock-based compensation expense | $		$ 8,200,000
Number of shares outstanding and unvested stock options		650,000
Performance Shares [Member] | Chief Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted			650,000
Time Based Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation granted under plan vested period			4 years	2 years
Share based compensation remaining vesting period			3 years
Share based compensation vesting frequency			quarterly
Outstanding and unvested restricted stock units		160,403
Total unrecognized stock-based compensation expense | $		$ 5,000,000
Restricted stock units granted		0	268,119	550,890
Fair value of restricted stock units vested | $		$ 9,500,000	$ 8,800,000
Restricted stock units vested		291,505	113,941	0
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%
Restricted stock units vested		74,509
Restricted Stock Units Vest One Year Anniversary [Member] | Time Based Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units vesting percentage			25%	25%
Restricted stock units vesting period month and year			2022-09	2021-04
Fair value of restricted stock units vested | $		$ 2,900,000
Restricted Stock Units Vest Two Year Anniversary [Member] | Time Based Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units vesting percentage			75%	75%
Restricted stock units vesting period month and year				2022-04
2011 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted		0
2014 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares annual increase added to plan	2,357,482
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 | $			$ 6,100,000	$ 3,400,000
Stock-based compensation expense | $			$ 3,800,000	$ 12,800,000
Milestones achieved | Milestone			2
2014 Plan [Member] | Performance Restricted Stock Units [Member] | Milestone One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Milestone performance restricted stock percentage				0.39	0.38
2014 Plan [Member] | Performance-Based Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Milestones achieved | Milestone		0	0	0
2014 Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of increase on outstanding shares of Common stock			4%
2016 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total number of shares reserved for issuance							1,200,000
2014 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total number of shares reserved for issuance						300,000		282,000
Number of shares issued under the plan		281,877
Accrued expenses | $		$ 0.8
Total number of shares available for issuance		300,123

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Activity Relating to Restricted Stock Units (Detail) - Restricted Stock Units [Member]	12 Months Ended
	Dec. 31, 2022 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding, Shares at beginning balance | shares	1,256,098
Granted, Shares | shares	705,380
Vested, Shares | shares	(366,014)
Forfeited, Shares | shares	(179,983)
Outstanding, Shares at ending balance | shares	1,415,481
Outstanding, Weighted Average Grant Date Fair Value at beginning balance | $ / shares	$ 57.87
Granted, Weighted Average Grant Date Fair Value | $ / shares	40.02
Vested, Weighted Average Grant Date Fair Value | $ / shares	40.13
Forfeited, Weighted Average Grant Date Fair Value | $ / shares	95.84
Outstanding, Weighted Average Grant Date Fair Value at ending balance | $ / shares	$ 48.73

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Activity Relating to Time Based and Performance Based Stock Options (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ending balance, Outstanding Shares	9,203,831
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, Outstanding Shares	7,283,439
Granted, Shares	1,181,487
Exercised, Shares	(156,195)
Forfeited, Shares	(520,381)
Ending balance, Outstanding Shares	7,788,350	7,283,439
Vested and expected to vest, Shares	6,724,505
Exercisable, Shares	5,109,027
Beginning balance, Outstanding Weighted Average Exercise Price	$ 84.17
Granted, Weighted Average Exercise Price	39.45
Exercised, Weighted Average Exercise Price	7.84
Forfeited, Weighted Average Exercise Price	98.65
Ending balance, Outstanding Weighted Average Exercise Price	77.95	$ 84.17
Vested and expected to vest, Weighted Average Exercise Price	78.86
Exercisable, Weighted Average Exercise Price	$ 85.76
Outstanding, Weighted Average Remaining Life	6 years 4 months 9 days	6 years 8 months 26 days
Vested and expected to vest, Weighted Average Remaining Life	6 years 18 days
Exercisable, Weighted Average Remaining Life	5 years 2 months 19 days
Outstanding, Aggregate Intrinsic Value	$ 7,275	$ 16,590
Vested and expected to vest, Aggregate Intrinsic Value	6,917
Exercisable, Aggregate Intrinsic Value	$ 5,607

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of Stock-Based Compensation Expense Recognized (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	$ 61,602	$ 104,629	$ 95,994
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	25,888	49,746	42,370
Selling, General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	$ 35,714	$ 54,883	51,836
Restructuring Charges [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense			$ 1,788

Stock-Based Compensation - Su_4

Stock-Based Compensation - Summary of Stock-Based Compensation Expense by Award Type (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	$ 61,602	$ 104,629	$ 95,994
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	54,971	78,516	90,064
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	5,587	25,375	4,904
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Stock-based compensation expense	$ 1,044	$ 738	$ 1,026

Stock-Based Compensation - Su_5

Stock-Based Compensation - Summary of Weighted Average Assumptions Used to Compute Fair Value of Option Granted (Detail)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-Based Payment Arrangement [Abstract]
Expected dividend yield	0%	0%	0%
Expected volatility	73%	76%	78%
Risk-free interest rate	2.49%	0.63%	0.97%
Expected term	6 years 10 days	5 years 11 months 1 day	5 years 11 months 23 days

Net Income (Loss) Per Share - S

Net Income (Loss) Per Share - Summary of Basic and Diluted Net Income (Loss) Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Numerator:
Net income (loss)	$ (532,784)	$ (457,892)	$ 606,073
Denominator:
Weighted average number of common shares outstanding—basic	59,306,094	58,670,230	51,983,188
Effect of dilutive securities:
Dilutive effect of shares of common stock equivalents	0	0	1,019,927
Weighted average common stock outstanding —diluted	59,306,094	58,670,230	53,003,115
Net income (loss) per share—basic	$ (8.98)	$ (7.80)	$ 11.66
Net income (loss) per share—diluted	$ (8.98)	$ (7.80)	$ 11.43
Stock Options [Member]
Effect of dilutive securities:
Dilutive effect of shares of common stock equivalents	0	0	721,791
Restricted Stock Units [Member]
Effect of dilutive securities:
Dilutive effect of shares of common stock equivalents	0	0	292,241
Employee Stock Purchase Plan [Member]
Effect of dilutive securities:
Dilutive effect of shares of common stock equivalents	0	0	5,895

Net Income (Loss) Per Share -_2

Net Income (Loss) Per Share - Summary of Anti-Dilutive Common Stock Equivalents Outstanding (Detail) - shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents	7,374,858	7,186,388	4,781,737
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents	7,138,350	6,599,429	4,781,737
Restricted Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents	160,403	563,334
Employee Stock Purchase Plan [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents	76,105	23,625

Income Taxes - Summary of Incom

Income Taxes - Summary of Income (Loss) Before Income Tax Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Domestic	$ (532,539)	$ (457,693)	$ 639,986
Foreign	(245)	(199)	(33,913)
Net income (loss) before income tax expense	$ (532,784)	$ (457,892)	$ 606,073

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)		12 Months Ended
	Aug. 16, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Line Items]
Current tax expense		$ 0
Research and development expense		326,163,000	$ 283,166,000	$ 292,714,000
Deferred tax expense		0
Inflation reduction of corporate alternative minimum tax	15%
Inflation reduction of excise tax on stock repurchases	1%
Federal operating loss carryforwards		$ 1,500,000,000
Federal net operating loss carryforwards, limitation percentage		80%
Federal orphan drug tax credit carry forwards		$ 40,100,000
Tax credit carry forwards expiration period		2034
Change in amount of deferred tax assets		$ 122,700,000
Valuation allowance		593,286,000	470,604,000
Valuation allowance, increase (decrease), amount		122,700,000	94,500,000	(107,200,000)
Accrued interest or penalties related to uncertain tax positions		0	0
Uncertain tax positions		0	$ 0	$ 0
Begin to Expire 2033 [Member]
Income Tax Disclosure [Line Items]
Federal operating loss carryforwards		$ 30,200,000
Federal net operating loss carryforwards expiration year		2033
Begin to Expire 2028 [Member]
Income Tax Disclosure [Line Items]
State operating loss carryforwards		$ 669,500,000
State net operating loss carryforwards expiration year		2031
Domestic Tax Authority [Member]
Income Tax Disclosure [Line Items]
Research and development tax credits carryforwards		$ 68,400,000
Research and development tax credits carryforwards expiration year		2031
State and Local Jurisdiction [Member]
Income Tax Disclosure [Line Items]
Research and development tax credits carryforwards		$ 12,500,000
Research and development tax credits carryforwards expiration year		2027
Research and Development Expense [Member]
Income Tax Disclosure [Line Items]
TCJA, Capitalized amout		$ 319,000,000

Income Taxes - Summary of Recon

Income Taxes - Summary of Reconciliation of U.S. Statutory Rate to Company's Effective Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Tax due at statutory rate	21%	21%	21%
State taxes, net of federal	1.80%	1.90%	5.70%
Biogen transaction-related items			(10.10%)
Stock-based compensation	(1.90%)	(5.20%)	0.90%
Foreign rate differential			1.20%
Federal and state tax credits	2.10%	3.50%	(1.50%)
Change in valuation allowance	(23.00%)	(20.70%)	(17.60%)
Other		(0.50%)	0.40%
Total effective tax rate	0%	0%	0%

Income Taxes - Summary of Signi

Income Taxes - Summary of Significant Components of Company's Net Deferred Tax Asset (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Net operating losses	$ 347,880	$ 305,824
Tax credits	118,393	106,176
Capitalized research and development expenses	66,849
Stock-based compensation	49,916	49,281
Accrued expenses	8,750	6,684
Depreciation and amortization	1,386	1,401
Right of use asset	(2,433)	(3,702)
Lease liability	2,803	4,236
Other	(258)	704
Total net deferred tax asset before valuation allowance	593,286	470,604
Valuation allowance	$ (593,286)	$ (470,604)

Income Taxes - Summary of Gross

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

Employee Benefit Plan - Additio

Employee Benefit Plan - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Postemployment Benefits [Abstract]
Employer matching contribution, percent of match	50%	50%	50%
Maximum annual contributions per employee, percent	6%	6%	6%
Employer contribution	$ 3	$ 1.8	$ 2.2
Defined Contribution Plan, Sponsor Location [Extensible Enumeration]	us-gaap:DomesticPlanMember	us-gaap:DomesticPlanMember	us-gaap:DomesticPlanMember
Defined Contribution Plan, Tax Status [Extensible Enumeration]	us-gaap:QualifiedPlanMember	us-gaap:QualifiedPlanMember	us-gaap:QualifiedPlanMember