Amylyx Pharmaceuticals (AMLX) 10-Q 9 Nov 23 2023 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2023	Nov. 06, 2023
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q3
Trading Symbol	AMLX
Entity Registrant Name	Amylyx Pharmaceuticals, Inc.
Entity Central Index Key	0001658551
Current Fiscal Year End Date	--12-31
Entity File Number	001-41199
Entity Tax Identification Number	46-4600503
Entity Address, Address Line One	43 Thorndike St.
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02141
City Area Code	617
Local Phone Number	682-0917
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		67,517,753
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
Document Quarterly Report	true
Document Transition Report	false

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 135,258	$ 62,526
Short-term investments	219,787	284,419
Accounts receivable, net	29,353	15,306
Inventories	32,374	9,769
Prepaid expenses and other current assets	17,338	10,113
Total current assets	434,110	382,133
Property and equipment, net	2,761	2,611
Restricted cash equivalents	719	719
Operating lease right-of-use assets	4,189	5,524
Long-term inventories	24,329
Other assets	476	466
Total assets	466,584	391,453
Current liabilities:
Accounts payable	6,371	6,257
Accrued expenses	37,045	38,312
Operating lease liabilities, current portion	2,201	2,040
Total current liabilities	45,617	46,609
Operating lease liabilities, net of current portion	2,567	4,237
Total liabilities	48,184	50,846
Commitments and contingencies (Note 13)
Stockholders' equity:
Preferred stock, $0.0001 par value; 10,000,000 shares authorized no shares issued or outstanding
Common stock, $0.0001 par value; 300,000,000 shares authorized; 67,505,126 and 66,512,011 shares issued and outstanding as of September 30, 2023 and December 31, 2022, respectively	7	7
Additional paid-in capital	728,224	694,906
Accumulated deficit	(309,680)	(354,220)
Accumulated other comprehensive loss	(151)	(86)
Total stockholders' equity	418,400	340,607
Total liabilities, redeemable convertable preferred stock and stockholders' equity	$ 466,584	$ 391,453

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Preferred stock par value	$ 0.0001	$ 0.0001
Preferred stock shares authorized	10,000,000	10,000,000
Preferred stock shares issued	0	0
Preferred stock shares outstanding	0	0
Common stock, stated par value per share	$ 0.0001	$ 0.0001
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares, issued	67,505,126	66,512,011
Common stock, shares, outstanding	67,505,126	66,512,011

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Income Statement [Abstract]
Product revenue, net	$ 102,693	$ 345	$ 272,337	$ 345
Revenue from Contract with Customer, Product and Service [Extensible Enumeration]	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember
Operating expenses:
Cost of sales	$ 5,218	$ 172	$ 16,081	$ 172
Research and development	30,037	24,914	83,273	70,637
Selling, general and administrative	48,718	29,940	136,115	86,284
Total operating expenses	83,973	55,026	235,469	157,093
Income (loss) from operations	18,720	(54,681)	36,868	(156,748)
Other income, net:
Interest income	4,179	601	11,784	1,134
Other (expense) income, net	(488)	199	(831)	138
Total other income, net	3,691	800	10,953	1,272
Income (loss) before income taxes	22,411	(53,881)	47,821	(155,476)
Provision (benefit) for income taxes	1,518	(125)	3,281	195
Net income (loss)	$ 20,893	$ (53,756)	$ 44,540	$ (155,671)
Net income (loss) per share attributable to common stockholders -basic	$ 0.31	$ (0.92)	$ 0.66	$ (2.77)
Net income (loss) per share attributable to common stockholders -diluted	$ 0.3	$ (0.92)	$ 0.63	$ (2.77)
Weighted-average shares used in computing net income (loss) per share attributable to common stockholders-basic	67,414,669	58,533,226	67,124,407	56,163,194
Weighted-average shares used in computing net income (loss) per share attributable to common stockholders-diluted	69,748,547	58,533,226	70,143,659	56,163,194

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 20,893	$ (53,756)	$ 44,540	$ (155,671)
Other comprehensive loss
Foreign currency translation loss	(138)	(559)	(78)	(569)
Net unrealized gain (loss) on investments held	59	30	13	(165)
Other comprehensive loss	(79)	(529)	(65)	(734)
Comprehensive income (loss)	$ 20,814	$ (54,285)	$ 44,475	$ (156,405)

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Series A Redeemable Convertible Preferred Share	Series B Redeemable Convertible Preferred Shares	Series C-1 Redeemable Convertible Preferred Shares	Series C-2 Redeemable Convertible Preferred Shares	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning Balance, Shares at Dec. 31, 2021		6,289,609	14,496,835	13,150,430	3,170,585
Beginning Balance at Dec. 31, 2021		$ 7,675	$ 64,387	$ 134,791	$ 32,498
Beginning Balance, Shares at Dec. 31, 2021						7,020,487
Beginning Balance at Dec. 31, 2021	$ (151,168)					$ 1	$ 4,667	$ 9	$ (155,845)
Conversion of preferred stock into common stock upon initial public offering, Shares						39,474,330
Conversion of preferred stock into common stock upon initial public offering	239,351					$ 4	239,347
Conversion of preferred stock into common stock upon initial public offering, Shares		(6,289,609)	(14,496,835)	(13,150,430)	(3,170,585)
Conversion of preferred stock into common stock upon initial public offering		$ (7,675)	$ (64,387)	$ (134,791)	$ (32,498)
Issuance of common stock upon initial public offering, net of issuance costs, Shares						11,369,369
Issuance of common stock upon initial public offering, net of issuance costs	196,379					$ 1	196,378
Stock-based compensation expense	4,392						4,392
Other comprehensive income (loss)	(160)							(160)
Net income (loss)	(47,848)								(47,848)
Ending Balance, Shares at Mar. 31, 2022						57,864,186
Ending Balance at Mar. 31, 2022	240,946					$ 6	444,784	(151)	(203,693)
Beginning Balance, Shares at Dec. 31, 2021		6,289,609	14,496,835	13,150,430	3,170,585
Beginning Balance at Dec. 31, 2021		$ 7,675	$ 64,387	$ 134,791	$ 32,498
Beginning Balance, Shares at Dec. 31, 2021						7,020,487
Beginning Balance at Dec. 31, 2021	(151,168)					$ 1	4,667	9	(155,845)
Net income (loss)	(155,671)
Ending Balance, Shares at Sep. 30, 2022						58,533,226
Ending Balance at Sep. 30, 2022	144,028					$ 6	456,263	(725)	(311,516)
Beginning Balance, Shares at Mar. 31, 2022						57,864,186
Beginning Balance at Mar. 31, 2022	240,946					$ 6	444,784	(151)	(203,693)
Issuance of common stock upon exercise of stock options, Shares						669,040
Issuance of common stock upon exercise of stock options	248						248
Stock-based compensation expense	5,707						5,707
Other comprehensive income (loss)	(45)							(45)
Net income (loss)	(54,067)								(54,067)
Ending Balance, Shares at Jun. 30, 2022						58,533,226
Ending Balance at Jun. 30, 2022	192,789					$ 6	450,739	(196)	(257,760)
Stock-based compensation expense	5,524						5,524
Other comprehensive income (loss)	(529)							(529)
Net income (loss)	(53,756)								(53,756)
Ending Balance, Shares at Sep. 30, 2022						58,533,226
Ending Balance at Sep. 30, 2022	$ 144,028					$ 6	456,263	(725)	(311,516)
Beginning Balance, Shares at Dec. 31, 2022	66,512,011					66,512,011
Beginning Balance at Dec. 31, 2022	$ 340,607					$ 7	694,906	(86)	(354,220)
Issuance of common stock upon exercise of stock options, Shares						451,298
Issuance of common stock upon exercise of stock options	2,777						2,777
Issuance of common stock upon vesting of RSUs						132,294
Stock-based compensation expense	7,580						7,580
Other comprehensive income (loss)	111							111
Net income (loss)	1,573								1,573
Ending Balance, Shares at Mar. 31, 2023						67,095,603
Ending Balance at Mar. 31, 2023	$ 352,648					$ 7	705,263	25	(352,647)
Beginning Balance, Shares at Dec. 31, 2022	66,512,011					66,512,011
Beginning Balance at Dec. 31, 2022	$ 340,607					$ 7	694,906	(86)	(354,220)
Issuance of common stock upon exercise of stock options, Shares	822,820
Net income (loss)	$ 44,540
Ending Balance, Shares at Sep. 30, 2023	67,505,126					67,505,126
Ending Balance at Sep. 30, 2023	$ 418,400					$ 7	728,224	(151)	(309,680)
Beginning Balance, Shares at Mar. 31, 2023						67,095,603
Beginning Balance at Mar. 31, 2023	352,648					$ 7	705,263	25	(352,647)
Issuance of common stock upon exercise of stock options, Shares						226,138
Issuance of common stock upon exercise of stock options	1,687						1,687
Issuance of common stock upon vesting of RSUs						32,676
Stock-based compensation expense	10,053						10,053
Other comprehensive income (loss)	(97)							(97)
Net income (loss)	22,074								22,074
Ending Balance, Shares at Jun. 30, 2023						67,354,417
Ending Balance at Jun. 30, 2023	386,365					$ 7	717,003	(72)	(330,573)
Issuance of common stock upon exercise of stock options, Shares						145,384
Issuance of common stock upon exercise of stock options	938						938
Issuance of common stock upon vesting of RSUs						5,325
Stock-based compensation expense	10,283						10,283
Other comprehensive income (loss)	(79)							(79)
Net income (loss)	$ 20,893								20,893
Ending Balance, Shares at Sep. 30, 2023	67,505,126					67,505,126
Ending Balance at Sep. 30, 2023	$ 418,400					$ 7	$ 728,224	$ (151)	$ (309,680)

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (Parenthetical) $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($)
Common Stock | Initial Public Offering
Issuance costs	$ 19,639

CONDENSED CONSOLIDATED STATEM_5

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Cash flows used in operating activities:
Net income (loss)	$ 44,540	$ (155,671)
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Stock-based compensation expense	27,627	15,623
Depreciation expense	787	305
Accretion of investment discounts, net	(7,368)	(196)
Changes in operating assets and liabilities:
Accounts receivable, net	(14,047)	(137)
Inventories	(46,648)	(563)
Interest receivable	370	(61)
Prepaid expenses and other current assets	(7,596)	(2,879)
Operating lease right-of-use assets	1,335	1,208
Other assets	(10)	(456)
Accounts payable	62	2,654
Accrued expenses	825	10,435
Operating lease liabilities	(1,509)	(436)
Net cash used in operating activities	(1,632)	(130,174)
Cash flows provided by (used in) investing activities:
Purchases of property and equipment	(885)	(1,906)
Purchases of investments	(174,187)	(154,313)
Proceeds from maturities of short-term investments	246,200	145,411
Net cash provided by (used in) investing activities	71,128	(10,808)
Cash flows provided by financing activities:
Proceeds from initial public offering		200,897
Initial public offering costs paid		(1,518)
Follow-on offering costs paid	(136)
Proceeds from exercise of stock options	6,647	248
Withholding taxes paid on stock-based awards	(3,198)
Net cash provided by financing activities	3,313	199,627
Effect of exchange rate changes on cash, cash equivalents and restricted cash equivalents	(77)	(572)
Net increase in cash, cash equivalents and restricted cash equivalents	72,732	58,073
Cash, cash equivalents and restricted cash equivalents, beginning of period	63,245	50,380
Cash, cash equivalents and restricted cash equivalents, end of period	135,977	108,453
Supplemental disclosure of cash flow information:
Unrealized gain (loss) on short-term investments	13	(165)
Taxes withheld on stock-based awards included in accrued expenses	15
Purchases of property and equipment included in accounts payable	150	43
Right-of-use assets and liabilities upon ASC 842 adoption		2,201
Right-of-use assets obtained in exchange for lease liabilities		4,958
Movement of deferred offering costs to equity		4,518
Initial public offering costs included in accounts payable and accrued expenses		526
Public offering costs included in accounts payable and accrued expenses		570
Conversion of preferred stock to common stock upon initial public offering		239,351
Income taxes paid	$ 4,978	$ 27

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
Pay vs Performance Disclosure
Net Income (Loss)	$ 20,893	$ 22,074	$ 1,573	$ (53,756)	$ (54,067)	$ (47,848)	$ 44,540	$ (155,671)

Insider Trading Arrangements

Insider Trading Arrangements	9 Months Ended
	Sep. 30, 2023 shares
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	During the three months ended September 30, 2023, the following officers or directors of the Company (as defined in Rule 16a-1(f)) adopted the following trading plans for the sale of our common stock pursuant to the terms of the applicable plan; such plans are intended to satisfy the affirmative defense conditions of Rule 10b5–1(c)(1) of the Exchange Act: • George Milne , a member of our board of dir ectors , adopted a new Rule 10b5-1 trading plan on September 15, 2023 , which is scheduled to expire on December 1, 2024 . The aggregate number of shares of our common stock authorized to be sold under this new arrangement is 106,000 . No other director or officer has adopted or terminated any non-Rule 10b5-1 trading arrangements during the quarter ended September 30, 2023 .
Non-Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Terminated	false
George Milne [Member]
Trading Arrangements, by Individual
Name	George Milne
Title	board of directors
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	September 15, 2023
Termination Date	December 1, 2024
Aggregate Available	106,000

Nature of the Business

Nature of the Business	9 Months Ended
	Sep. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of the Business	1. Nature of the Business Amylyx Pharmaceuticals, Inc., together with its wholly owned subsidiaries, known as Amylyx or the Company, is a commercial-stage biotechnology company with a mission to one day end the suffering caused by neurodegenerative diseases. The Company is pursuing amyotrophic lateral sclerosis, or ALS, as its first indication and is focused on the development and potential commercialization of AMX0035 for ALS globally. AMX0035 is approved by the U.S. Food and Drug Administration, or the FDA, and marketed as RELYVRIO ® (sodium phenylbutyrate and taurursodiol, also known as ursodoxicoltaurine) for the treatment of ALS in adults in the U.S. AMX0035 is also approved with conditions by Health Canada and marketed as ALBRIOZA™ for the treatment of ALS in Canada. The Company continues to focus on the completion of its global PHOENIX Phase 3 clinical trial, which will provide additional data on the efficacy and safety profile of AMX0035 in people living with ALS, and is also developing AMX0035 in other neurodegenerative diseases. AMX0035 was designed to target endoplasmic reticulum, or ER, stress and mitochondrial dysfunction, two connected central pathways that can lead to neurodegeneration. The Company is further investigating AMX0035 in diseases where ER and mitochondrial stress are implicated, including progressive supranuclear palsy, or PSP, and Wolfram syndrome, or WS. The Company dosed the first participant in the HELIOS trial, a Phase 2 trial of AMX0035 for the treatment of WS, in April 2023 and plans to initiate the ORION trial, a global, pivotal Phase 3 trial of AMX0035 for the treatment of PSP, by the end of 2023. The Company is also advancing additional drug candidates for neurodegenerative diseases including AMX0114, an antisense oligonucleotide targeting Calpain-2, a key protein in axonal degeneration, among others. Risks and Uncertainties The Company is subject to risks and uncertainties common to companies in the biotechnology industry, including, but not limited to, the outcome of preclinical studies and clinical trials, market acceptance and the successful commercialization of its approved products ALBRIOZA, which received marketing authorization with conditions in Canada in June 2022, and RELYVRIO, which was approved by the FDA in the U.S. in September 2022, potential difficulties with or delays in timing with respect to regulatory approval processes, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations, ability to secure additional capital to fund operations, and risks associated with the economic challenges caused by global health crises such as the COVID-19 pandemic and economic uncertainty in various global markets caused by geopolitical instability and conflict. The Company and its contractors may experience disruptions in supply of items that are essential for its research and development and commercial activities, including, for example, raw materials and bulk drug substances that the Company imports from Europe and Canada used in the manufacturing of AMX0035, and any additional or future product candidates .

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Significant Accounting Policies The Company’s significant accounting policies are disclosed in the audited consolidated financial statements for the year ended December 31, 2022 and the notes thereto, which are included in the Company’s most recent Annual Report on Form 10-K. Since the date of those consolidated financial statements, there have been no material changes to its significant accounting policies, with the exception of significant accounting policies related to the adoption of the Financial Accounting Standards Board, or FASB, Accounting Standards Codification, or ASC, Topic 326, Financial Instruments—Credit Losses , or ASC 326, effective January 1, 2023, as described below. Basis of Presentation and Consolidation The accompanying condensed consolidated financial statements are unaudited and have been prepared in conformity with accounting principles generally accepted in the U.S., or GAAP, and include the accounts of the Company and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. In the opinion of the Company's management, all normal and recurring adjustments necessary for a fair presentation have been reflected. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the ASC, and Accounting Standards Update, or ASU, of the FASB. Use of Estimates The preparation of the condensed consolidated financial statements in conformity with GAAP requires the Company’s management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amount of expenses during the reporting period. Actual results could differ from those estimates. Management considers many factors in selecting appropriate financial accounting policies in developing the estimates and assumptions that are used in the preparation of the financial statements. Management must apply significant judgment in this process. Management’s estimation process often may yield a range of potentially reasonable estimates and management must select an amount that falls within that range of reasonable estimates. Estimates are used in the following areas, among others: gross-to-net, or GTN, adjustments; recoverability of inventories, including those produced in preparation for product launches; accrued expenses; stock option valuations; valuation allowance for deferred tax assets and research and development expense s. Recently Adopted Accounting Pronouncements In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326) Measurement of Credit Losses on Financial Instruments , or ASU 2016-13. The provisions of ASU 2016-13 modify the impairment model to utilize an expected loss methodology in place of the currently used incurred loss methodology and require a consideration of a broader range of reasonable and supportable information to inform credit loss estimates. Credit losses relating to available-for-sale debt securities will be recorded through an allowance for credit losses rather than as a direct write-down to the security. ASU 2016-13 requires a cumulative effect adjustment to the consolidated balance sheet as of the beginning of the first reporting period in which the guidance is effective. The Company adopted ASU 2016-13 effective January 1, 2023, with no material impact on its consolidated financial statements and related disclosures.

Product Revenue, Net

Product Revenue, Net	9 Months Ended
	Sep. 30, 2023
Revenue from Contract with Customer [Abstract]
Product Revenue, Net	3. PRODUCT REVENUE, NET To date, the Company’s only source of product revenue has been from the sales of RELYVRIO, known as ALBRIOZA in Canada. Significant judgment is required in estimating GTN adjustments considering historical experience, payer channel mix, current contract prices, unbilled claims, processing time lags, inventory levels in the distribution ch annel and estimated product returns. The following table reconciles gross product revenue to net product revenue (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Product revenue, gross $ 111,864 $ 547 $ 304,822 $ 547 GTN adjustments ( 9,171 ) ( 202 ) ( 32,485 ) ( 202 ) Product revenue, net $ 102,693 $ 345 $ 272,337 $ 345 The activity and ending reserve balance for GTN adjustments were as follows for the nine months ended September 30, 2023 and 2022 (in thousands): Chargebacks and Cash Discounts Medicaid and Medicare Rebates Other Rebates, Returns, Discounts and Adjustments Total Ending balance at December 31, 2022 $ 648 $ 1,992 $ 1,664 $ 4,304 Provision related to sales in the current year 14,175 7,872 10,954 33,001 Adjustments related to prior period sales — ( 236 ) ( 280 ) ( 516 ) Credits and payments made ( 11,004 ) ( 6,806 ) ( 8,930 ) ( 26,740 ) Ending balance at September 30, 2023 $ 3,819 $ 2,822 $ 3,408 $ 10,049 Chargebacks and Cash Discounts Medicaid and Medicare Rebates Other Rebates, Returns, Discounts and Adjustments Total Ending balance at December 31, 2021 $ — $ — $ — $ — Provision related to sales in the current year 3 — 199 202 Adjustments related to prior period sales — — — — Credits and payments made ( 2 ) — — ( 2 ) Ending balance at September 30, 2022 $ 1 $ — $ 199 $ 200 Included in the ending reserve balance for GTN adjustments are chargebacks resulting from contractual commitments to sell products to qualified healthcare providers at prices lower than the list prices charged to customers who directly purchase the product from the Company, discounts to customers for prompt payment and estimates for product returns. Chargebacks, discounts and returns are recorded as reductions of accounts receivable, net on the condensed consolidated balance sheets. In addition, included in the ending reserve balance for GTN adjustments are Medicaid and Medicare rebates, other rebates for obligations under voluntary patient assistance programs, and accrued fees payable to customers. Medicaid and Medicare rebates, other rebates and fees are recorded as a component of accrued expenses on the condensed consolidated balance sheets.

Short-Term Investments

Short-Term Investments	9 Months Ended
	Sep. 30, 2023
Investments, Debt and Equity Securities [Abstract]
Short-Term Investments	4. SHORT-TERM INVESTMENTS The Company determines the appropriate classification of marketable securities at the time of purchase and reevaluates such designation at each balance sheet date. The Company has classified all of its marketable securities at September 30, 2023 as “available-for-sale” pursuant to ASC 320, Investments – Debt and Equity Securities . The Company records available-for-sale securities at fair value, with the unrealized gains and losses included as a separate component of other accumulated comprehensive income (loss). There were no realized gains or losses recognized during the three and nine months ended September 30, 2023 and 2022. The Company adjusts the cost of available-for-sale debt securities for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion are included in interest income. The cost of securities sold is based on the specific identification method. The Company includes interest and dividends on securities classified as available-for-sale in interest income. Accrued interest receivable relating to the Company's available-for-sale securities is presented within prepaid expenses and other current assets in the accompanying condensed consolidated balance sheets, and amounted to $ 0.1 million and $ 0.5 million at September 30, 2023 and December 31, 2022, respectively. The following is a summary of available-for-sale securities with unrealized losses for less than 12 months as of September 30, 2023 and December 31, 2022 (in thousands): September 30, 2023 December 31, 2022 Fair Value Unrealized Losses Fair Value Unrealized Losses Treasury notes $ — $ — $ 27,159 $ ( 14 ) Treasury bills 39,569 ( 1 ) 9,839 ( 2 ) Commercial paper 30,865 ( 18 ) — — Corporate debt securities — — 33,486 ( 55 ) Agency bonds 9,940 ( 13 ) — — Total available-for-sale securities in an unrealized loss position $ 80,374 $ ( 32 ) $ 70,484 $ ( 71 ) At September 30, 2023, the Company's security portfolio consisted of 18 securities related to investments in debt securities available-for-sale, of which 8 se curities were in an unrealized loss position. There were no securities in an unrealized loss position for greater than 12 months as of September 30, 2023. The contractual terms of these investments do not permit the issuer to settle the securities at a price less than the amortized cost bases of the investments. The Company does not intend to sell the investments and it is not more likely than not that the Company will be required to sell the investments before recovery of their amortized cost bases. The Company did not record an allowance for credit losses as of September 30, 2023. Prior to January 1, 2023, the Company evaluated short-term investments for other-than-temporary impairment at the balance sheet date. Declines in fair value, if any, determined to be other-than-temporary were also included in other income, net. When assessing short-term investments for other-than-temporary declines in value, the Company considered such factors as, among other things, how significant the decline in value is as a percentage of the original cost, how long the market value of the investment has been less than its original cost, and the Company’s ability and intent to retain the investment for a period of time sufficient to allow for any anticipated recovery in fair value and market conditions in general. The Company determined it did not hold any investments with any other-than-temporary impairment as of December 31, 2022. Short-term investments, which are classified as available-for-sale, consisted of the following (in thousands): Balance at September 30, 2023: Amortized Unrealized Unrealized Fair Treasury notes $ 5,000 $ — $ — $ 5,000 Treasury bills 166,055 8 ( 1 ) 166,062 Commercial paper 30,883 — ( 18 ) 30,865 Corporate debt securities 7,920 — — 7,920 Agency bonds 9,953 — ( 13 ) 9,940 Total short-term investments $ 219,811 $ 8 $ ( 32 ) $ 219,787 Balance at December 31, 2022: Amortized Unrealized Unrealized Fair Treasury notes $ 27,173 $ — $ ( 14 ) $ 27,159 Treasury bills 59,326 10 ( 2 ) 59,334 Commercial paper 134,375 — — 134,375 Corporate debt securities 58,795 13 ( 55 ) 58,753 Agency bonds 4,781 17 — 4,798 Total short-term investments $ 284,450 $ 40 $ ( 71 ) $ 284,419

Inventories

Inventories	9 Months Ended
	Sep. 30, 2023
Inventory Disclosure [Abstract]
Inventories	5. INVENTORIES Inventories consisted of the following (in thousands): September 30, 2023 December 31, 2022 Raw materials $ 38,106 $ 7,151 Work in process 6,311 1,681 Finished goods 12,286 937 Total inventories $ 56,703 $ 9,769 The Company capitalizes inventory costs associated with its products after regulatory approval when, based on management’s judgment, future commercialization is considered probable and the future economic benefit is expected to be realized. As of September 30, 2023, the Company had $ 6.6 million of in ventory on hand that was acquired prior to regulatory approvals. This inventory was expensed to research and development as the future economic benefit was not probable. The Company began to capitalize inventory costs upon receipt of regulatory approvals in 2022. Finished goods have a shelf life of 12 - 18 months from the date of manufacture. The Company classifies inventory as long-term inventory when consumption or sale of the inventory is expected beyond one year.

Accrued Expenses

Accrued Expenses	9 Months Ended
	Sep. 30, 2023
Payables and Accruals [Abstract]
Accrued Expenses	6. Accrued Expenses Accrued expenses consisted of the following (in thousands): September 30, 2023 December 31, 2022 Accrued external research and development $ 6,441 $ 8,424 Accrued benefits and incentive compensation 11,896 15,231 Accrued manufacturing 2,050 4,596 Accrued consulting and other professional fees 6,572 4,116 Accrued rebates and co-pay assistance 6,056 3,582 Accrued royalties 3,111 1,358 Other accrued expenses 919 1,005 Total accrued expenses $ 37,045 $ 38,312

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2023
Fair Value Disclosures [Abstract]
Fair Value Measurements	7 . FAIR VALUE MEASUREMENTS The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis and indicates the level of the fair value hierarchy utilized to determine such fair values (in thousands): September 30, 2023 Level 1 Level 2 Level 3 Total Assets: Cash equivalents $ 54,706 $ — $ — $ 54,706 Short-term investments: Treasury notes 5,000 — — 5,000 Treasury bills 166,062 — — 166,062 Commercial paper — 30,865 — 30,865 Corporate debt securities — 7,920 — 7,920 Agency bonds — 9,940 — 9,940 Total short-term investments 171,062 48,725 — 219,787 Restricted cash equivalents 719 — — 719 Total financial assets $ 226,487 $ 48,725 $ — $ 275,212 December 31, 2022 Level 1 Level 2 Level 3 Total Assets: Cash equivalents $ 23,567 $ 9,989 $ — $ 33,556 Short-term investments: Treasury notes 27,159 — — 27,159 Treasury bills 59,334 — — 59,334 Commercial paper — 134,375 — 134,375 Corporate debt securities — 58,753 — 58,753 Agency bonds — 4,798 — 4,798 Total short-term investments 86,493 197,926 — 284,419 Restricted cash equivalents 719 — — 719 Total financial assets $ 110,779 $ 207,915 $ — $ 318,694 The Company classifies its money market funds, treasury notes and treasury bills as Level 1 assets under the fair value hierarchy, as these assets have been valued using quoted market prices for identical assets in active markets without any valuation adjustment. The Company classifies its commercial paper, corporate debt securities, and agency bonds as Level 2 assets under the fair value hierarchy, as these assets have been valued using information obtained through a third-party pricing service at each balance sheet date, using observable market inputs that may include trade information, broker or dealer quotes, bids, offers, or a combination of these data sources.

Leases

Leases	9 Months Ended
	Sep. 30, 2023
Leases [Abstract]
Leases	8. Leases The Company adopted ASC 842 on January 1, 2022. ASC 842 allows the Company to elect a package of practical expedients, which include: (i) an entity need not reassess whether any expired or existing contracts are or contain leases; (ii) an entity need not reassess the lease classification for any expired or existing leases; and (iii) an entity need not reassess any initial direct costs for any existing leases. Another practical expedient allows the Company to use hindsight in determining the lease term when considering lessee options to extend or terminate the lease and to purchase the underlying asset. The Company elected to utilize this package of practical expedients and did not elect the hindsight methodology in its implementation of ASC 842. The Company leases its office facilities under non-cancelable operating leases that expire at various dates through October 2026. Components of lease expense required by ASC 842 are presented below for the three and nine months ended September 30, 2023 (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Lease cost Operating lease cost $ 543 $ 544 $ 1,631 $ 1,592 Total lease cost $ 543 $ 544 $ 1,631 $ 1,592 During the nine months ended September 30, 2023, the Company made cash payments of $ 1.8 million for operating leases. Future minimum lease payments under non-cancelable leases as of September 30, 2023, were as detailed below (in thousands): September 30, 2023 2023 (remaining 3 months) $ 611 2024 2,478 2025 1,586 2026 476 2027 — Total undiscounted lease payments 5,151 Less: imputed interest ( 383 ) Total operating lease liabilities $ 4,768 As of September 30, 2023, the weighted average remaining lease term was 2.2 years and the weighted average incremental borrowing rate used to determine the operating lease right-of-use assets was 7.3 % .

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2023
Income Tax Disclosure [Abstract]
Income Taxes	9. Income taxes For the three months ended September 30, 2023 and 2022, the Company recorded an income tax provision of $ 1.5 million and an income tax benefit $ 0.1 million , respectively. The income tax provision (benefit) for the three months ended September 30, 2023 and 2022 was primarily driven by the estimated effective tax rate for the year, as well as discrete income tax benefit of $ 0.1 million and zero , respectively. For the nine months ended September 30, 2023 and 2022, the Company recorded an income tax provision of $ 3.3 million and $ 0.2 million , respectively. The income tax provision for the nine months ended September 30, 2023 and 2022 was primarily driven by the estimated effective tax rate for the year, as well as discrete income tax benefit of $ 0.5 million and zero , respectively. The income tax provision for the three and nine months ended September 30, 2023 includes the release of a portion of the Company’s valuation allowance that has been reversed through the annual effective tax rate with respect to amounts expected to be realized through current year taxable income.

Stock Option and Grant Plan

Stock Option and Grant Plan	9 Months Ended
	Sep. 30, 2023
Share-Based Payment Arrangement [Abstract]
Stock Option and Grant Plan	10. Stock Option and Grant Plan Stock Incentive Plan General Option Information A summary of option activity for the nine months ended September 30, 2023, is as follows: Number of Weighted- Weighted- Aggregate Outstanding at December 31, 2022 8,480,950 $ 13.19 8.2 $ 201,765 Granted 2,557,569 $ 31.36 Exercised ( 822,820 ) $ 6.57 $ 18,360 Cancelled or forfeited ( 266,882 ) $ 17.72 Outstanding at September 30, 2023 9,948,817 $ 18.28 8.0 $ 44,547 Options exercisable as of September 30, 2023 3,525,568 $ 11.49 7.0 $ 26,785 Options unvested as of September 30, 2023 6,423,249 $ 22.01 8.6 $ 17,762 Weighted average grant-date fair value of options granted during the period $ 20.74 The aggregate intrinsic value of stock options is calculated as the difference between the exercise price of the options and the fair value of the Company’s common stock for those options that had exercise prices lower than the fair value of the Company’s common stock. The aggregate intrinsic value of options exercised during the nine months ended September 30, 2023 and 2022 was $ 18.4 million and $ 6.0 million , respectively. The total fair value of stock options vested during the nine months ended September 30, 2023 and 2022 was $ 24.8 million and $ 5.1 million , respectively. Restricted Stock Unit Activity A summary of restricted stock unit activity for the nine months ended September 30, 2023, is as follows: Number of Shares Weighted Average Grant Date Fair Value Nonvested as of December 31, 2022 740,297 $ 20.02 Granted 548,066 $ 31.47 Vested ( 170,295 ) $ 18.64 Forfeited ( 34,009 ) $ 25.04 Nonvested as of September 30, 2023 1,084,059 $ 25.87 Summary of Stock-Based Compensation Expense Stock-based compensation expense recorded in the condensed consolidated statements of operations for the three and nine months ended September 30, 2023 and 2022, is as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Research and development $ 2,664 $ 1,416 $ 7,090 $ 4,001 Selling, general and administrative 7,512 4,108 20,537 11,622 Total stock-based compensation expense $ 10,176 $ 5,524 $ 27,627 $ 15,623 The Company capitalized stock-based compensation expense of $ 0.1 million and $ 0.3 million for the three and nine months ended September 30, 2023 , respectively. The Company did no t capitalize any stock-based compensation expense during the three and nine months ended September 30, 2022. Stock-based compensation recognized through cost of sales was less than $ 0.1 million and $ 0.1 million for the three and nine months ended September 30, 2023. The following table summarizes stock-based compensation by type of award (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Stock options $ 8,274 $ 4,748 $ 22,645 $ 13,611 Restricted stock units 1,902 776 4,982 2,012 Total stock-based compensation expense $ 10,176 $ 5,524 $ 27,627 $ 15,623 The following table summarizes unrecognized stock-based compensation expense as of September 30, 2023, by type of awards (in thousands), and the weighted-average period over which that expense is expected to be recognized (in years). The total unrecognized stock-based compensation expense will be adjusted for actual forfeitures as they occur. September 30, 2023 Unrecognized Expense Weighted-average Recognition Period Stock options $ 87,543 2.81 Restricted stock units $ 23,313 3.09

Net Income (Loss) Per Share

Net Income (Loss) Per Share	9 Months Ended
	Sep. 30, 2023
Earnings Per Share [Abstract]
Net Income (Loss) Per Share	11. NET INCOME (LOSS) PER SHARE Net Income (Loss) per Share Attributable to Common Stockholders Basic earnings per share is computed by dividing net income (loss) by the weighted average number of common shares outstanding during the period. Diluted earnings per share is calculated based on the combined weighted average number of common shares and potentially dilutive shares, which include the assumed exercise of employee stock options and unvested restricted stock units. In computing diluted earnings per share, the Company utilizes the treasury stock method. A summary of the numerator and denominators used in the computation of earnings per share follows (in thousands, except share and per share data): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Numerator: Net income (loss) $ 20,893 $ ( 53,756 ) $ 44,540 $ ( 155,671 ) Denominator: Weighted-average shares used to compute basic net income (loss) per share 67,414,669 58,533,226 67,124,407 56,163,194 Dilutive effect of employee stock options and restricted stock units 2,333,878 — 3,019,252 — Weighted-average shares used to compute diluted net income (loss) per share 69,748,547 58,533,226 70,143,659 56,163,194 Net income (loss) per share attributable to common stockholders Basic $ 0.31 $ ( 0.92 ) $ 0.66 $ ( 2.77 ) Diluted $ 0.30 $ ( 0.92 ) $ 0.63 $ ( 2.77 ) Because the Company reported a net loss attributable to common stockholders for the three and nine months ended September 30, 2022, basic and diluted net loss per share attributable to common stockholders were the same. All stock options and restricted stock units were excluded from the computation of diluted weighted-average shares outstanding because such securities would have an antidilutive impact for the three and nine months ended September 30, 2022 . The following stock options and restricted stock units outstanding at each period end have been excluded from the calculation of diluted net income (loss) per share because their inclusion would have been antidilutive: Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Options to purchase common stock 5,971,476 8,575,449 5,937,376 8,575,449 Restricted stock units 626,086 687,913 510,173 687,913 Total excluded common stock equivalents 6,597,562 9,263,362 6,447,549 9,263,362

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2023
Related Party Transactions [Abstract]
Related Party Transactions	12. Related party transactions Supplier Agreements In the ordinary course of business, the Company may purchase materials or supplies or services from entities that are associated with a party that meets the criteria of a related party of the Company. These transactions are reviewed quarterly and to date have not been material to the Company’s condensed consolidated financial statements.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	13. Commitments and Contingencies Lease Commitments The Company has two operating lease agreements for its office space. See Note 8 for additional information. Letter of Credit Restricted cash equivalents consist of $ 0.2 million of cash serving as collateral for a letter of credit issued for the Company’s office space, and $ 0.5 million as collateral for a corporate credit card program. As of September 30, 2023 and December 31, 2022, the Company’s restricted cash equivalents balance was $ 0.7 million on its condensed consolidated balance sheets. Legal Proceedings The Company is not currently a party to any material legal proceedings. At each reporting date, the Company evaluates whether or not a potential loss amount or potential range of loss is probable and reasonably estimated under the provisions of the authoritative guidance that addresses accounting for contingencies. The Company recognizes expenses for its costs related to its legal proceedings, as incurred. Royalty Payments Between August 2016 and February 2019, the Company entered into grant agreements with the ALS Association, ALS Finding a Cure Foundation, Alzheimer’s Drug Discovery Foundation, Alzheimer’s Association and Cure Alzheimer’s Fund, or Grantors. Under the terms of the agreements, the Company was granted, in aggregate, $ 4.3 million. These grants were provided to the Company for the purpose of furthering the research and development of AMX0035 as a therapeutic benefit for ALS and Alzheimer’s disease. Under the terms of the arrangements, the Company would receive a tranche of funds as it completed certain milestones. Pursuant to the terms of the grant agreements, the Company has certain payment obligations that are contingent upon future events such as the achievement of commercialization or the receipt of proceeds from a revenue generating transaction resulting from the projects for which the grants are used for. Pursuant to the terms of the respective grant agreements among the Company, ALS Association and ALS Finding a Cure, the Company will be required to make royalty payments to each Grantor in the total amount equal to 150 % of the grant received. The royalty payments will be achieved through a combination of the following payment methods: (i) an annual installment payment of 3 % of net sales of any products developed under the project for which the grant was used for and (ii) 3 % of cash proceeds resulting from revenue generating transaction under the project for which the grants are used for. During the three months ended September 30, 2023 , the Company did no t record any royalty expense. During the nine months ended September 30, 2023, the Company recorded $ 3.1 million in royalty expense, which is included in cost of sales in the condensed consolidated financial statements. As of September 30, 2023 , no further royalties remain to be accrued under the grant agreements with the ALS Association and ALS Finding a Cure Foundation. Under the terms of the respective grant agreements among the Company, Alzheimer’s Drug Discovery Foundation, the Alzheimer’s Association, and Cure Alzheimer’s Fund, the Company will make royalty payments up to the maximum amount of $ 15.0 million to each Grantor (or $ 45.0 million in aggregate). The royalty payment will be made through a combination of the following payment methods: (i) 4 % of annual net sales of any product commercialized from the project for which the grant was used for and directly related to the treatment of the Alzheimer’s disease and (ii) 15 % of all royalties and cash proceeds resulting from revenue generating transactions associated with the projects for which the grants were used for under the grant agreements. As the conditions that would trigger royalty payments under the agreements have not occurred, no amounts have been recorded in the condensed consolidated financial statements for the three and nine months ended September 30, 2023 and 2022. Purchase Commitments The Company enters into agreements in the normal course of business with contract manufacturing organizations for raw material purchases and manufacturing services. As of September 30, 2023, the Company had committed approximately $ 211.1 million under these agreements related to raw material purchases and manufacturing services, which are expected to b e paid through 2028.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2023
Subsequent Events [Abstract]
Subsequent Events	14. Subsequent Events The Company has evaluated all subsequent events after September 30, 2023 and through the date of this filing, and there were no material subsequent events requiring disclosure, except as described below. In October 2023, the Committee for Medicinal Products for Human Use, or CHMP, of the European Medicines Agency confirmed its initial negative opinion on the Marketing Authorisation Application for AMX0035, under the trade name ALBRIOZA®, for the treatment of adults with ALS in the European Union. The decision follows the conclusion of the CHMP’s formal re-examination procedure of an initial negative opinion adopted in June 2023.The CHMP opinion will be forwarded to the European Commission, which will adopt the final decision on this application. A decision is anticipated by the end of 2023.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation The accompanying condensed consolidated financial statements are unaudited and have been prepared in conformity with accounting principles generally accepted in the U.S., or GAAP, and include the accounts of the Company and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. In the opinion of the Company's management, all normal and recurring adjustments necessary for a fair presentation have been reflected. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the ASC, and Accounting Standards Update, or ASU, of the FASB.
Use of Estimates	Use of Estimates The preparation of the condensed consolidated financial statements in conformity with GAAP requires the Company’s management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amount of expenses during the reporting period. Actual results could differ from those estimates. Management considers many factors in selecting appropriate financial accounting policies in developing the estimates and assumptions that are used in the preparation of the financial statements. Management must apply significant judgment in this process. Management’s estimation process often may yield a range of potentially reasonable estimates and management must select an amount that falls within that range of reasonable estimates. Estimates are used in the following areas, among others: gross-to-net, or GTN, adjustments; recoverability of inventories, including those produced in preparation for product launches; accrued expenses; stock option valuations; valuation allowance for deferred tax assets and research and development expense
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326) Measurement of Credit Losses on Financial Instruments , or ASU 2016-13. The provisions of ASU 2016-13 modify the impairment model to utilize an expected loss methodology in place of the currently used incurred loss methodology and require a consideration of a broader range of reasonable and supportable information to inform credit loss estimates. Credit losses relating to available-for-sale debt securities will be recorded through an allowance for credit losses rather than as a direct write-down to the security. ASU 2016-13 requires a cumulative effect adjustment to the consolidated balance sheet as of the beginning of the first reporting period in which the guidance is effective. The Company adopted ASU 2016-13 effective January 1, 2023, with no material impact on its consolidated financial statements and related disclosures.

Product Revenue, Net (Tables)

Product Revenue, Net (Tables)	9 Months Ended
	Sep. 30, 2023
Revenue from Contract with Customer [Abstract]
Summary of Gross Product Revenue to Net Product Revenue	The following table reconciles gross product revenue to net product revenue (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Product revenue, gross $ 111,864 $ 547 $ 304,822 $ 547 GTN adjustments ( 9,171 ) ( 202 ) ( 32,485 ) ( 202 ) Product revenue, net $ 102,693 $ 345 $ 272,337 $ 345
Schedule of Activity and Ending Reserve Balance for GTN Adjustments	The activity and ending reserve balance for GTN adjustments were as follows for the nine months ended September 30, 2023 and 2022 (in thousands): Chargebacks and Cash Discounts Medicaid and Medicare Rebates Other Rebates, Returns, Discounts and Adjustments Total Ending balance at December 31, 2022 $ 648 $ 1,992 $ 1,664 $ 4,304 Provision related to sales in the current year 14,175 7,872 10,954 33,001 Adjustments related to prior period sales — ( 236 ) ( 280 ) ( 516 ) Credits and payments made ( 11,004 ) ( 6,806 ) ( 8,930 ) ( 26,740 ) Ending balance at September 30, 2023 $ 3,819 $ 2,822 $ 3,408 $ 10,049 Chargebacks and Cash Discounts Medicaid and Medicare Rebates Other Rebates, Returns, Discounts and Adjustments Total Ending balance at December 31, 2021 $ — $ — $ — $ — Provision related to sales in the current year 3 — 199 202 Adjustments related to prior period sales — — — — Credits and payments made ( 2 ) — — ( 2 ) Ending balance at September 30, 2022 $ 1 $ — $ 199 $ 200

Short-Term Investments (Tables)

Short-Term Investments (Tables)	9 Months Ended
	Sep. 30, 2023
Investments, Debt and Equity Securities [Abstract]
Summary of Available-for-sale Securities with Unrealized Losses for Less Than 12 Months	The following is a summary of available-for-sale securities with unrealized losses for less than 12 months as of September 30, 2023 and December 31, 2022 (in thousands): September 30, 2023 December 31, 2022 Fair Value Unrealized Losses Fair Value Unrealized Losses Treasury notes $ — $ — $ 27,159 $ ( 14 ) Treasury bills 39,569 ( 1 ) 9,839 ( 2 ) Commercial paper 30,865 ( 18 ) — — Corporate debt securities — — 33,486 ( 55 ) Agency bonds 9,940 ( 13 ) — — Total available-for-sale securities in an unrealized loss position $ 80,374 $ ( 32 ) $ 70,484 $ ( 71 )
Schedule of Short-term Investments Classified as Available-for-sale	Short-term investments, which are classified as available-for-sale, consisted of the following (in thousands): Balance at September 30, 2023: Amortized Unrealized Unrealized Fair Treasury notes $ 5,000 $ — $ — $ 5,000 Treasury bills 166,055 8 ( 1 ) 166,062 Commercial paper 30,883 — ( 18 ) 30,865 Corporate debt securities 7,920 — — 7,920 Agency bonds 9,953 — ( 13 ) 9,940 Total short-term investments $ 219,811 $ 8 $ ( 32 ) $ 219,787 Balance at December 31, 2022: Amortized Unrealized Unrealized Fair Treasury notes $ 27,173 $ — $ ( 14 ) $ 27,159 Treasury bills 59,326 10 ( 2 ) 59,334 Commercial paper 134,375 — — 134,375 Corporate debt securities 58,795 13 ( 55 ) 58,753 Agency bonds 4,781 17 — 4,798 Total short-term investments $ 284,450 $ 40 $ ( 71 ) $ 284,419

Inventories (Tables)

Inventories (Tables)	9 Months Ended
	Sep. 30, 2023
Inventory Disclosure [Abstract]
Summary of Inventories	Inventories consisted of the following (in thousands): September 30, 2023 December 31, 2022 Raw materials $ 38,106 $ 7,151 Work in process 6,311 1,681 Finished goods 12,286 937 Total inventories $ 56,703 $ 9,769

Accrued Expenses (Tables)

Accrued Expenses (Tables)	9 Months Ended
	Sep. 30, 2023
Payables and Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consisted of the following (in thousands): September 30, 2023 December 31, 2022 Accrued external research and development $ 6,441 $ 8,424 Accrued benefits and incentive compensation 11,896 15,231 Accrued manufacturing 2,050 4,596 Accrued consulting and other professional fees 6,572 4,116 Accrued rebates and co-pay assistance 6,056 3,582 Accrued royalties 3,111 1,358 Other accrued expenses 919 1,005 Total accrued expenses $ 37,045 $ 38,312

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2023
Fair Value Disclosures [Abstract]
Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis	The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis and indicates the level of the fair value hierarchy utilized to determine such fair values (in thousands): September 30, 2023 Level 1 Level 2 Level 3 Total Assets: Cash equivalents $ 54,706 $ — $ — $ 54,706 Short-term investments: Treasury notes 5,000 — — 5,000 Treasury bills 166,062 — — 166,062 Commercial paper — 30,865 — 30,865 Corporate debt securities — 7,920 — 7,920 Agency bonds — 9,940 — 9,940 Total short-term investments 171,062 48,725 — 219,787 Restricted cash equivalents 719 — — 719 Total financial assets $ 226,487 $ 48,725 $ — $ 275,212 December 31, 2022 Level 1 Level 2 Level 3 Total Assets: Cash equivalents $ 23,567 $ 9,989 $ — $ 33,556 Short-term investments: Treasury notes 27,159 — — 27,159 Treasury bills 59,334 — — 59,334 Commercial paper — 134,375 — 134,375 Corporate debt securities — 58,753 — 58,753 Agency bonds — 4,798 — 4,798 Total short-term investments 86,493 197,926 — 284,419 Restricted cash equivalents 719 — — 719 Total financial assets $ 110,779 $ 207,915 $ — $ 318,694

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2023
Leases [Abstract]
Components of Lease Expense	Components of lease expense required by ASC 842 are presented below for the three and nine months ended September 30, 2023 (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Lease cost Operating lease cost $ 543 $ 544 $ 1,631 $ 1,592 Total lease cost $ 543 $ 544 $ 1,631 $ 1,592
Summary of Future Minimum Lease Payments	Future minimum lease payments under non-cancelable leases as of September 30, 2023, were as detailed below (in thousands): September 30, 2023 2023 (remaining 3 months) $ 611 2024 2,478 2025 1,586 2026 476 2027 — Total undiscounted lease payments 5,151 Less: imputed interest ( 383 ) Total operating lease liabilities $ 4,768

Stock Option and Grant Plan (Ta

Stock Option and Grant Plan (Tables)	9 Months Ended
	Sep. 30, 2023
Share-Based Payment Arrangement [Abstract]
Summary of Stock Option Activity	A summary of option activity for the nine months ended September 30, 2023, is as follows: Number of Weighted- Weighted- Aggregate Outstanding at December 31, 2022 8,480,950 $ 13.19 8.2 $ 201,765 Granted 2,557,569 $ 31.36 Exercised ( 822,820 ) $ 6.57 $ 18,360 Cancelled or forfeited ( 266,882 ) $ 17.72 Outstanding at September 30, 2023 9,948,817 $ 18.28 8.0 $ 44,547 Options exercisable as of September 30, 2023 3,525,568 $ 11.49 7.0 $ 26,785 Options unvested as of September 30, 2023 6,423,249 $ 22.01 8.6 $ 17,762 Weighted average grant-date fair value of options granted during the period $ 20.74
Summary of Restricted Stock Unit Activity	A summary of restricted stock unit activity for the nine months ended September 30, 2023, is as follows: Number of Shares Weighted Average Grant Date Fair Value Nonvested as of December 31, 2022 740,297 $ 20.02 Granted 548,066 $ 31.47 Vested ( 170,295 ) $ 18.64 Forfeited ( 34,009 ) $ 25.04 Nonvested as of September 30, 2023 1,084,059 $ 25.87
Summary of Stock-Based Compensation Expense	Stock-based compensation expense recorded in the condensed consolidated statements of operations for the three and nine months ended September 30, 2023 and 2022, is as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Research and development $ 2,664 $ 1,416 $ 7,090 $ 4,001 Selling, general and administrative 7,512 4,108 20,537 11,622 Total stock-based compensation expense $ 10,176 $ 5,524 $ 27,627 $ 15,623
Summary of Stock-Based Compensation by Type of Award	The following table summarizes stock-based compensation by type of award (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Stock options $ 8,274 $ 4,748 $ 22,645 $ 13,611 Restricted stock units 1,902 776 4,982 2,012 Total stock-based compensation expense $ 10,176 $ 5,524 $ 27,627 $ 15,623
Summary of Unrecognized Stock-Based Compensation Expense and Weighted-Average Recognition Period	The following table summarizes unrecognized stock-based compensation expense as of September 30, 2023, by type of awards (in thousands), and the weighted-average period over which that expense is expected to be recognized (in years). The total unrecognized stock-based compensation expense will be adjusted for actual forfeitures as they occur. September 30, 2023 Unrecognized Expense Weighted-average Recognition Period Stock options $ 87,543 2.81 Restricted stock units $ 23,313 3.09

Net Income (Loss) Per Share (Ta

Net Income (Loss) Per Share (Tables)	9 Months Ended
	Sep. 30, 2023
Earnings Per Share [Abstract]
Summary of the Numerator and Denominators Used in Computation of Earnings Per Share	A summary of the numerator and denominators used in the computation of earnings per share follows (in thousands, except share and per share data): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Numerator: Net income (loss) $ 20,893 $ ( 53,756 ) $ 44,540 $ ( 155,671 ) Denominator: Weighted-average shares used to compute basic net income (loss) per share 67,414,669 58,533,226 67,124,407 56,163,194 Dilutive effect of employee stock options and restricted stock units 2,333,878 — 3,019,252 — Weighted-average shares used to compute diluted net income (loss) per share 69,748,547 58,533,226 70,143,659 56,163,194 Net income (loss) per share attributable to common stockholders Basic $ 0.31 $ ( 0.92 ) $ 0.66 $ ( 2.77 ) Diluted $ 0.30 $ ( 0.92 ) $ 0.63 $ ( 2.77 )
Schedule of Antidilutive Shares Excluded from the Calculation of Diluted Net Income (Loss) Per Share	The following stock options and restricted stock units outstanding at each period end have been excluded from the calculation of diluted net income (loss) per share because their inclusion would have been antidilutive: Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Options to purchase common stock 5,971,476 8,575,449 5,937,376 8,575,449 Restricted stock units 626,086 687,913 510,173 687,913 Total excluded common stock equivalents 6,597,562 9,263,362 6,447,549 9,263,362

Product Revenue, Net - Summary

Product Revenue, Net - Summary of Gross Product Revenue to Net product Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Revenue from Contract with Customer [Abstract]
Product revenue, gross	$ 111,864	$ 547	$ 304,822	$ 547
GTN adjustments	(9,171)	(202)	(32,485)	(202)
Product revenue, net	$ 102,693	$ 345	$ 272,337	$ 345

Product Revenue, Net - Schedule

Product Revenue, Net - Schedule of Activity and Ending Reserve Balance for GTN Adjustments (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Disaggregation of Revenue [Line Items]
GTN Adjustments, Ending balance	$ 4,304
GTN Adjustments, Provision related to sales in the current year	33,001	$ 202
GTN Adjustments, Adjustments related to prior period sales	(516)
GTN Adjustments, Credits and payments made	(26,740)	(2)
GTN Adjustments, Ending balance	10,049	200
Chargebacks and Cash Discounts
Disaggregation of Revenue [Line Items]
GTN Adjustments, Ending balance	648
GTN Adjustments, Provision related to sales in the current year	14,175	3
GTN Adjustments, Credits and payments made	(11,004)	(2)
GTN Adjustments, Ending balance	3,819	1
Medicaid and Medicare Rebates
Disaggregation of Revenue [Line Items]
GTN Adjustments, Ending balance	1,992
GTN Adjustments, Provision related to sales in the current year	7,872
GTN Adjustments, Adjustments related to prior period sales	(236)
GTN Adjustments, Credits and payments made	(6,806)
GTN Adjustments, Ending balance	2,822
Other Rebates, Returns, Discounts and Adjustments
Disaggregation of Revenue [Line Items]
GTN Adjustments, Ending balance	1,664
GTN Adjustments, Provision related to sales in the current year	10,954	199
GTN Adjustments, Adjustments related to prior period sales	(280)
GTN Adjustments, Credits and payments made	(8,930)
GTN Adjustments, Ending balance	$ 3,408	$ 199

Short-Term Investments - Additi

Short-Term Investments - Additional Information (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2023 USD ($) Security	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($) Security	Sep. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)
Debt Securities, Available-for-Sale [Line Items]
Realized gains | $	$ 0	$ 0	$ 0	$ 0
Realized loss | $	$ 0	$ 0	$ 0	$ 0
Debt securities available-for-sale number of positions | Security	18		18
Debt securities available-for-sale number of positions in an unrealized loss position | Security	8		8
Debt securities available-for-sale in an unrealized loss position for greater than 12 months | Security	0		0
Available-for-Sale Securities
Debt Securities, Available-for-Sale [Line Items]
Accrued interest receivable | $	$ 100,000		$ 100,000		$ 500,000

Short-Term Investments - Summar

Short-Term Investments - Summary of Available-for-sale Securities with Unrealized Losses for Less Than 12 Months (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Debt Securities, Available-for-Sale [Line Items]
Fair Value	$ 80,374	$ 70,484
Unrealized Losses	(32)	(71)
Commercial Paper
Debt Securities, Available-for-Sale [Line Items]
Fair Value	30,865
Unrealized Losses	(18)
Treasury notes
Debt Securities, Available-for-Sale [Line Items]
Fair Value		27,159
Unrealized Losses		(14)
Treasury Bills
Debt Securities, Available-for-Sale [Line Items]
Fair Value	39,569	9,839
Unrealized Losses	(1)	(2)
Corporate Debt Securities
Debt Securities, Available-for-Sale [Line Items]
Fair Value		33,486
Unrealized Losses		$ (55)
Agency Bonds
Debt Securities, Available-for-Sale [Line Items]
Fair Value	9,940
Unrealized Losses	$ (13)

Short-Term Investments - Schedu

Short-Term Investments - Schedule of Short-term Investments Classified as Available-for-sale (Details) - Short-term Investments - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost Basis	$ 219,811	$ 284,450
Unrealized Gain	8	40
Unrealized Loss	(32)	(71)
Fair Value	219,787	284,419
Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost Basis	30,883	134,375
Unrealized Loss	(18)
Fair Value	30,865	134,375
Treasury notes
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost Basis	5,000	27,173
Unrealized Loss		(14)
Fair Value	5,000	27,159
Treasury Bills
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost Basis	166,055	59,326
Unrealized Gain	8	10
Unrealized Loss	(1)	(2)
Fair Value	166,062	59,334
Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost Basis	7,920	58,795
Unrealized Gain		13
Unrealized Loss		(55)
Fair Value	7,920	58,753
Agency Bonds
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost Basis	9,953	4,781
Unrealized Gain		17
Unrealized Loss	(13)
Fair Value	$ 9,940	$ 4,798

Inventories - Summary of Invent

Inventories - Summary of Inventory (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Inventory Disclosure [Abstract]
Raw materials	$ 38,106	$ 7,151
Work in process	6,311	1,681
Finished goods	12,286	937
Total inventories	$ 56,703	$ 9,769

Inventories - Additional Inform

Inventories - Additional Information (Details) $ in Millions	9 Months Ended
	Sep. 30, 2023 USD ($)
Public Utilities, Inventory [Line Items]
Inventory acquired expensed as research and development expense	$ 6.6
Finished Goods | Maximum
Public Utilities, Inventory [Line Items]
Shelf life	18 months
Finished Goods | Minimum
Public Utilities, Inventory [Line Items]
Shelf life	12 months

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Accrued external research and development	$ 6,441	$ 8,424
Accrued benefits and incentive compensation	11,896	15,231
Accrued Manufacturing	2,050	4,596
Accrued consulting and other professional fees	6,572	4,116
Accrued rebates and co-pay assistance	6,056	3,582
Accrued royalties	3,111	1,358
Other accrued expenses	919	1,005
Total accrued expenses	$ 37,045	$ 38,312

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - Fair Value Measurements, Recurring - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	$ 275,212	$ 318,694
Cash equivalents
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	54,706	33,556
Restricted Cash Equivalents
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	719	719
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	226,487	110,779
Level 1 | Cash equivalents
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	54,706	23,567
Level 1 | Restricted Cash Equivalents
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	719	719
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	48,725	207,915
Level 2 | Cash equivalents
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents		9,989
Short-term Investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	219,787	284,419
Short-term Investments | Treasury notes
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	5,000	27,159
Short-term Investments | Treasury Bills
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	166,062	59,334
Short-term Investments | Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	30,865	134,375
Short-term Investments | Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	7,920	58,753
Short-term Investments | Agency Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	9,940	4,798
Short-term Investments | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	171,062	86,493
Short-term Investments | Level 1 | Treasury notes
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	5,000	27,159
Short-term Investments | Level 1 | Treasury Bills
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	166,062	59,334
Short-term Investments | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	48,725	197,926
Short-term Investments | Level 2 | Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	30,865	134,375
Short-term Investments | Level 2 | Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	7,920	58,753
Short-term Investments | Level 2 | Agency Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets measured at fair value	$ 9,940	$ 4,798

Leases- Additional Information

Leases- Additional Information (Details) $ in Millions	9 Months Ended
	Sep. 30, 2023 USD ($)
Leases [Abstract]
Operating lease, cash payments	$ 1.8
Weighted-average remaining lease term (years)	2 years 2 months 12 days
Weighted average incremental borrowing rate	7.30%

Leases - Components of Lease Ex

Leases - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Leases [Abstract]
Operating lease cost	$ 543	$ 544	$ 1,631	$ 1,592
Total lease cost	$ 543	$ 544	$ 1,631	$ 1,592

Leases - Summary of Future Mini

Leases - Summary of Future Minimum Lease Payments (Detail) $ in Thousands	Sep. 30, 2023 USD ($)
Leases [Abstract]
2023 (remaining 3 months)	$ 611
2024	2,478
2025	1,586
2026	476
Total undiscounted lease payments	5,151
Less: imputed interest	(383)
Total operating lease liabilities	$ 4,768

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Income Tax Disclosure [Abstract]
(Benefit) provision for income taxes	$ 1,518	$ (125)	$ 3,281	$ 195
Discrete income tax (benefit) provision	$ 100	$ 0	$ 500	$ 0

Stock Option and Grant Plan - S

Stock Option and Grant Plan - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Number of Options, Outstanding	8,480,950
Number of Options, Granted	2,557,569
Number of Options, Exercised	(822,820)
Number of Options, Cancelled or forfeited	(266,882)
Number of Options, Outstanding	9,948,817		8,480,950
Number of Options, Options exercisable	3,525,568
Number of Options, Options unvested	6,423,249
Weighted average grant-date fair value of options granted during the period	$ 20.74
Weighted-Average Exercise Price, Outstanding	13.19
Weighted-Average Exercise Price, Granted	31.36
Weighted-Average Exercise Price, Exercised	6.57
Weighted-Average Exercise Price, Cancelled or forfeited	17.72
Weighted-Average Exercise Price, Outstanding	18.28		$ 13.19
Weighted-Average Exercise Price, Options exercisable	11.49
Weighted-Average Exercise Price, Options unvested	$ 22.01
Weighted- Average Remaining Contractual Term (in years), Outstanding	8 years		8 years 2 months 12 days
Weighted- Average Remaining Contractual Term (in years), Options exercisable	7 years
Weighted- Average Remaining Contractual Term (in years), Options unvested	8 years 7 months 6 days
Aggregate Intrinsic Value, Outstanding	$ 201,765
Aggregate intrinsic value, exercised	18,360	$ 6,000
Aggregate Intrinsic Value, Outstanding	44,547		$ 201,765
Aggregate Intrinsic Value, Options exercisable	26,785
Aggregate Intrinsic Value, Options unvested	$ 17,762

Stock Option and Grant Plan - A

Stock Option and Grant Plan - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Aggregate intrinsic value, exercised			$ 18,360,000	$ 6,000,000
Total fair value of stock options vested			24,800,000	5,100,000
Capitalized stock-based compensation expense	$ 100,000	$ 0	300,000	0
Stock-based compensation recognized	10,176,000	$ 5,524,000	27,627,000	$ 15,623,000
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation recognized	$ 100,000		$ 100,000

Stock Option and Grant Plan -_2

Stock Option and Grant Plan - Summary of Restricted Stock Unit Activity (Details) - Restricted Stock Unit	9 Months Ended
	Sep. 30, 2023 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, Nonvested | shares	740,297
Number of shares, Granted | shares	548,066
Number of shares, Vested | shares	(170,295)
Number of shares, Forfeited | shares	(34,009)
Number of shares, Nonvested | shares	1,084,059
Weighted Average Grant Date Fair Value, Nonvested | $ / shares	$ 20.02
Weighted Average Grant Date Fair Value, Granted | $ / shares	31.47
Weighted Average Grant Date Fair Value, Vested | $ / shares	18.64
Weighted Average Grant Date Fair Value, Forfeited | $ / shares	25.04
Weighted Average Grant Date Fair Value, Nonvested | $ / shares	$ 25.87

Stock Option and Grant Plan -_3

Stock Option and Grant Plan - Summary of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 10,176	$ 5,524	$ 27,627	$ 15,623
Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	2,664	1,416	7,090	4,001
Selling, General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 7,512	$ 4,108	$ 20,537	$ 11,622

Stock Option and Grant Plan -_4

Stock Option and Grant Plan - Summary of Stock-Based Compensation by Type of Award (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 10,176	$ 5,524	$ 27,627	$ 15,623
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	8,274	4,748	22,645	13,611
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 1,902	$ 776	$ 4,982	$ 2,012

Stock Option and Grant Plan -_5

Stock Option and Grant Plan - Summary of Unrecognized Stock-Based Compensation Expense and Weighted-Average Recognition Period (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2023 USD ($)
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized Expense	$ 87,543
Weighted-average Recognition Period	2 years 9 months 21 days
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized Expense	$ 23,313
Weighted-average Recognition Period	3 years 1 month 2 days

Net Income (Loss) Per Share - S

Net Income (Loss) Per Share - Summary of the Numerator and Denominators Used in Computation of Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
Numerator:
Net income (loss)	$ 20,893	$ 22,074	$ 1,573	$ (53,756)	$ (54,067)	$ (47,848)	$ 44,540	$ (155,671)
Denominator:
Weighted-average shares used to compute basic net income (loss) per share	67,414,669			58,533,226			67,124,407	56,163,194
Dilutive effect of employee stock options and restricted stock units	2,333,878						3,019,252
Weighted-average shares used to compute diluted net income (loss) per share	69,748,547			58,533,226			70,143,659	56,163,194
Net income (loss) per share attributable to common stockholders -basic	$ 0.31			$ (0.92)			$ 0.66	$ (2.77)
Net income (loss) per share attributable to common stockholders -diluted	$ 0.3			$ (0.92)			$ 0.63	$ (2.77)

Net Income (Loss) Per Share -_2

Net Income (Loss) Per Share - Schedule of Antidilutive Shares Excluded from the Calculation of Diluted Net Income (Loss) Per Share (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total excluded common stock equivalents	6,597,562	9,263,362	6,447,549	9,263,362
Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total excluded common stock equivalents	5,971,476	8,575,449	5,937,376	8,575,449
Restricted Stock Unit
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total excluded common stock equivalents	626,086	687,913	510,173	687,913

Commitment and Contingencies -

Commitment and Contingencies - Additional Information (Details)	3 Months Ended	9 Months Ended	31 Months Ended
	Sep. 30, 2023 USD ($)	Sep. 30, 2023 USD ($) LeaseAgreement	Feb. 28, 2019 USD ($)	Dec. 31, 2022 USD ($)
Commitments And Contingencies [Line Items]
Number of operating lease agreements | LeaseAgreement		2
Restricted cash	$ 700,000	$ 700,000		$ 700,000
Raw Material Purchases and Manufacturing Services
Commitments And Contingencies [Line Items]
Purchase commitments	211,100,000	211,100,000
ALS Association and ALS Finding a Cure
Commitments And Contingencies [Line Items]
Accrued royalities grant agreements	0	0
ALS Association and ALS Finding a Cure | Cost of Sales
Commitments And Contingencies [Line Items]
Royalty expense	0	3,100,000
Royalty Payments Agreements with Grantors
Commitments And Contingencies [Line Items]
Proceeds from grants			$ 4,300,000
Royalty Payments Agreements with Grantors | ALS Association and ALS Finding a Cure
Commitments And Contingencies [Line Items]
Percentage of grant received			150%
Percentage of net sales of products developed under projects			3%
Percentage of cash proceeds from revenue generating transaction			3%
Royalty Payments Agreements with Grantors | Alzheimer's Drug Discovery Foundation, the Alzheimer's Association, and Cure Alzheimer's Fund
Commitments And Contingencies [Line Items]
Maximum Royalty amount payable to each grantor			$ 15,000,000
Aggregate royalty amount payable to grantor			$ 45,000,000
Percentage of annual net sales of products commercialized from project			4%
Percentage of all royalties and cash proceeds from revenue generating transaction			15%
Collateral for Letter of Credit Issued
Commitments And Contingencies [Line Items]
Restricted cash	200,000	200,000
Collateral for Corporate Credit Card Program
Commitments And Contingencies [Line Items]
Restricted cash	$ 500,000	$ 500,000