Syndax Pharmaceuticals (SNDX) 10-Q 8 May 23 2023 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2023	May 03, 2023
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q1
Trading Symbol	SNDX
Entity Registrant Name	Syndax Pharmaceuticals, Inc.
Entity Central Index Key	0001395937
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		68,821,277
Entity Shell Company	false
Title of 12(b) Security	Common Stock
Security Exchange Name	NASDAQ
Entity File Number	001-37708
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	32-0162505
Entity Address, Address Line One	35 Gatehouse Drive
Entity Address, Address Line Two	Building D
Entity Address, Address Line Three	Floor 3
Entity Address, City or Town	Waltham
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02451
City Area Code	781
Local Phone Number	419-1400
Document Quarterly Report	true
Document Transition Report	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 57,517	$ 74,356
Short-term investments	374,876	401,446
Short-term deposits	5,812	8,595
Collaboration receivable, net	1,393	3,474
Prepaid expenses and other current assets	1,913	1,915
Total current assets	441,511	489,786
Long-term investments	16,561	5,469
Property and equipment, net	17	20
Right-of-use asset, net	929	1,039
Restricted cash	115	115
Other assets	693	807
Total assets	459,826	497,236
Current liabilities:
Accounts payable	8,057	4,350
Accrued expenses and other current liabilities	15,205	24,276
Current portion of right-of-use liability	454	434
Current portion of capital lease	5	5
Total current liabilities	23,721	29,065
Long-term liabilities:
Right-of-use liability, less current portion	588	709
Capital lease, less current portion	12	13
Total long-term liabilities	600	722
Total liabilities	24,321	29,787
Commitments and contingencies (Note 12)
Stockholders’ equity:
Preferred stock, $0.001 par value, 10,000,000 shares authorized; 0 shares outstanding at March 31, 2023 and December 31, 2022	0	0
Common stock, $0.0001 par value, 100,000,000 shares authorized; 68,495,426 and 68,111,385 shares issued and outstanding at March 31, 2023 and December 31, 2022, respectively	7	7
Additional paid-in capital	1,170,000	1,161,288
Accumulated other comprehensive loss	(336)	(806)
Accumulated deficit	(734,166)	(693,040)
Total stockholders’ equity	435,505	467,449
Total liabilities and stockholders’ equity	$ 459,826	$ 497,236

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Mar. 31, 2023	Dec. 31, 2022
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	68,495,426	68,111,385
Common stock, shares outstanding	68,495,426	68,111,385

Condensed Consolidated Statemen

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Operating expenses:
Research and development	$ 34,054	$ 30,022
General and administrative	11,961	6,836
Total operating expenses	46,015	36,858
Loss from operations	(46,015)	(36,858)
Other (expense) income, net:
Interest expense	(40)	(651)
Interest income	5,076	224
Other (expense) income, net	(147)	116
Total other (expense) income, net	4,889	(311)
Net loss	(41,126)	(37,169)
Other comprehensive loss:
Unrealized (loss) gain on marketable securities	470	(685)
Comprehensive loss	(40,656)	(37,854)
Net loss attributable to common stockholders - basic	$ (41,126)	$ (37,169)
Net loss per share attributable to common stockholders—basic	$ (0.59)	$ (0.63)
Net loss per share attributable to common stockholders—diluted	$ (0.59)	$ (0.63)
Weighted-average number of common shares used to compute net loss per share attributable to common stockholders —basic	69,438,890	58,978,615
Weighted-average number of common shares used to compute net loss per share attributable to common stockholders—diluted	69,438,890	58,978,615

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (41,126,000)	$ (37,169,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	3,000	11,000
Accretion of investments	(3,967,000)	(53,000)
Non-cash operating lease expense	110,000	110,000
Non-cash interest expense	0	152,000
Changes in fair value of derivative liability	0	(187,000)
Stock-based compensation	6,238,000	3,478,000
Changes in operating assets and liabilities:
Prepaid expenses and other assets	2,899,000	(8,431,000)
Collaboration receivable, net	2,082,000	(6,260,000)
Accounts payable	3,707,000	2,562,000
Accrued expenses and other liabilities	(9,174,000)	3,856,000
Net cash used in operating activities	(39,228,000)	(41,931,000)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of short and long-term investments	(61,585,000)	(42,266,000)
Proceeds from sales and maturities of short-term investments	81,500,000	50,448,000
Net cash provided by investing activities	19,915,000	8,182,000
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from Employee Stock Purchase Plan	196,000	92,000
Proceeds from stock option exercises	2,278,000	465,000
Net cash provided by financing activities	2,474,000	557,000
NET DECREASE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	(16,839,000)	(33,192,000)
CASH, CASH EQUIVALENTS AND RESTRICTED CASH—beginning of period	74,471,000	222,080,000
CASH, CASH EQUIVALENTS AND RESTRICTED CASH —end of period	57,632,000	188,888,000
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Cash paid for interest	$ 0	$ 470,000

Nature of Business

Nature of Business	3 Months Ended
	Mar. 31, 2023
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature of Business	1. Nature of Business Syndax Pharmaceuticals, Inc. (“we,” “us,” “our” or the “Company”) is a clinical stage biopharmaceutical company developing an innovative pipeline of cancer therapies. We were incorporated in Delaware in 2005. We base our operations in Waltham, Massachusetts and we operate in one segment.

Basis of Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation	2. Basis of Presentation The Company has prepared the accompanying condensed consolidated financial statements in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”). Certain information and footnote disclosures normally included in the Company’s annual financial statements have been condensed or omitted. The interim unaudited condensed financial statements have been prepared on the same basis as the annual audited financial statements and in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statement of the Company’s financial position as of March 31, 2023, and the results of operations and comprehensive loss for the three months ended March 31, 2023 and 2022, and cash flows for the three months ended March 31, 2023 and 2022. The results for the three months ended March 31, 2023 are not necessarily indicative of the results to be expected for the year ending December 31, 2023, any other interim periods, or any future year or period. These interim financial statements should be read in conjunction with the audited financial statements as of and for the year ended December 31, 2022, and the notes thereto, which are included in the Company’s Annual Report on Form 10-K as filed with the Securities and Exchange Commission (“SEC”) on February 28, 2023. Certain prior amounts reported in the accompanying condensed consolidated financial statements and notes thereto have been reclassified to conform to the current year presentation. Specifically, the change in collaboration receivable presented within the condensed statement of cash flows for the three month period ended March 31, 2022, of $ 6.3 million was originally reported within the caption prepaid expense and current assets and has been separately presented in the comparative presentation. Such reclassifications did not affect loss from operations, total assets, cash used in operations or net loss. In 2011, the Company established a wholly owned subsidiary in the United Kingdom. In 2014, the Company established a wholly owned U.S. subsidiary, and in 2021, the Company established a wholly owned subsidiary in the Netherlands. To date, there have been no material activities for these entities. All intercompany balances and transactions have been eliminated in consolidation.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	3. Summary of Significant Accounting Policies Significant Accounting Policies The Company’s significant accounting policies, which are disclosed in the audited consolidated financial statements for the year ended December 31, 2022, and the notes thereto are included in the Company’s Annual Report on Form 10-K that was filed with the SEC on February 28, 2023 . Since the date of filing, there have been no material changes to the Company’s significant accounting policies except as noted below. Use of Estimates The preparation of condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of costs and expenses during the reporting period. The Company bases estimates and assumptions on historical experience when available and on various factors that it believes to be reasonable under the circumstances. The Company evaluates its estimates and assumptions on an ongoing basis. Estimates and assumptions about future events and their effects cannot be determined with certainty and therefore require the exercise of judgment. As of the date of issuance of these financial statements, the Company is not aware of any specific event or circumstance that would require the Company to update its estimates, assumptions and judgments or revise the carrying value of its assets or liabilities. These estimates may change as new events occur and additional information is obtained and are recognized in the consolidated financial statements as soon as they become known. Actual results could differ from those estimates and any such differences may be material to the Company’s condensed consolidated financial statements. Significant Risks and Uncertainties We are subject to challenges and risks specific to our business and our ability to execute on our strategy, as well as risks and uncertainties common to companies in the pharmaceutical industry with development and commercial operations, including, without limitation, risks and uncertainties associated with: obtaining regulatory approval of our late-stage product candidate; delays or problems in the supply of our products, loss of single source suppliers or failure to comply with manufacturing regulations; identifying, acquiring or in-licensing additional products or product candidates; pharmaceutical product development and the inherent uncertainty of clinical success; and the challenges of protecting and enhancing our intellectual property rights; complying with applicable regulatory requirements. Recently Issued and Adopted Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (“FASB”) or other accounting standard setting bodies that we adopt as of the specified effective date. Unless otherwise discussed below, we do not believe that the adoption of recently issued standards have or may have a material impact on our consolidated statements or disclosures.

Collaborative Research and Lice

Collaborative Research and License Agreements	3 Months Ended
	Mar. 31, 2023
Research And Development [Abstract]
Collaborative Research and License Agreements	Collaborative Research and License Agreements Incyte Collaboration In September 2021, the Company entered into the Incyte License and Collaboration Agreement, or the Incyte License, with Incyte covering the worldwide development and commercialization of axatilimab. Also in September 2021, the Company entered into a share purchase agreement with Incyte, or the Incyte Share Purchase Agreement. These agreements are collectively referred to as the Incyte Agreements. Under the terms of the Incyte Agreements, Incyte received exclusive commercialization rights outside of the United States, subject to certain royalty payment obligations set forth below. In the United States, Incyte and the Company will co-commercialize axatilimab, with the Company having the right to co-promote axatilimab with Incyte, subject to the Company’s exercise of its co-promotion option. Incyte will be responsible for leading all aspects of the commercialization of axatilimab in the United States. The Company and Incyte will share equally the profits and losses from co-commercialization efforts in the United States. The Company and Incyte have agreed to co-develop axatilimab and to share development costs associated with global and U.S. – specific clinical trials, with Incyte responsible for 55 % of such costs and the Company responsible for 45 % of such costs. Each company will be responsible for funding any of its own independent development activities. Incyte is responsible for 100 % of future development costs for trials that are specific to ex-U.S. countries. All development costs related to the collaboration will be subject to a joint development plan. Under the terms of the Incyte Agreements, in December 2021, Incyte paid the Company a non-refundable cash payment of $ 117 million and the Company issued 1,421,523 shares of common stock with an aggregate purchase price of $ 35 million, or $ 24.62 per share. Additionally, under the terms of the Incyte Agreements, the Company is eligible to receive up to $ 220 million in future contingent development and regulatory milestones and up to $ 230 million in commercialization milestones as well as tiered royalties ranging in the mid-teens percentage on net sales of the licensed product comprising axatilimab in Europe and Japan and low double digit percentage in the rest of the world outside of the United States. The Company's right to receive royalties in any particular country will expire upon the last to occur of (a) the expiration of licensed patent rights covering the licensed product in that particular country, (b) a specified period of time after the first post - marketing authorization sale of a licensed product in that country, and (c) the expiration of any regulatory exclusivity for that licensed product in that country. As of March 31, 2023, the Company has recorded $ 3.5 million as a collaboration receivable due from Incyte related to the Company's development and pre-commercialization costs under the Agreement and has recorded approximately $ 2.1 million as a collaboration payable due to Incyte for development and pre-commercialization costs incurred by Incyte as of March 31, 2023 . Both expense and cost offset are recorded as part of research and development expense and general and administrative expense.

Net Loss per Share Attributable

Net Loss per Share Attributable to Common Stockholders	3 Months Ended
	Mar. 31, 2023
Earnings Per Share [Abstract]
Net Loss per Share Attributable to Common Stockholders	5. Net Loss per Share Attributable to Common Stockholders Basic net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common shares outstanding for the period. Because the Company has reported a net loss for all periods presented, diluted net loss per common share is the same as basic net loss per common share for those periods. The following table summarizes the computation of basic and diluted net loss per share attributable to common stockholders of the Company: Three Months Ended March 31, 2023 2022 (In thousands, except share and per Numerator—basic and diluted: Net loss $ ( 41,126 ) $ ( 37,169 ) Net loss attributable to common $ ( 41,126 ) $ ( 37,169 ) Net loss per share attributable to common $ ( 0.59 ) $ ( 0.63 ) Denominator—basic and diluted: Weighted-average number of common shares 69,438,890 58,978,615 The following potentially dilutive securities have been excluded from the computation of diluted weighted-average shares outstanding because such securities have an antidilutive impact due to losses reported (in common stock equivalent shares): March 31, 2023 2022 Options to purchase common stock 9,536,312 8,419,541 Employee Stock Purchase Plan 15,331 10,805 Non-vested restricted stock units (RSUs) 392,288 256,583 For additional information related to the Company's common stock see Note 10.

Significant Agreements

Significant Agreements	3 Months Ended
	Mar. 31, 2023
Equity [Abstract]
Significant Agreements	6. Significant Agreements Vitae Pharmaceuticals, Inc. In October 2017, the Company entered into a license agreement (the “Allergan License Agreement”) with Vitae Pharmaceuticals, Inc., a subsidiary of Allergan (“Allergan”), under which Allergan granted the Company an exclusive, sublicensable, worldwide license to a portfolio of preclinical, orally available, small molecule inhibitors of the Menin–KMT2A binding interaction (the “Menin Assets”). Subject to the achievement of certain milestone events, the Company may be required to pay Allergan up to $ 99.0 million in one-time development and regulatory milestone payments over the term of the Allergan License Agreement. In the event that the Company or any of its affiliates or sublicensees commercializes the Menin Assets, the Company will also be obligated to pay Allergan low single to low double-digit royalties on sales, subject to reduction in certain circumstances, as well as up to an aggregate of $ 70.0 million in potential one-time, sales-based milestone payments based on achievement of certain annual sales thresholds. The Company is solely responsible for the development and commercialization of the Menin Assets. Each party may terminate the Allergan License Agreement for the other party’s uncured material breach or insolvency, and the Company may terminate the Allergan License Agreement at any time upon advance written notice to Allergan. Allergan may terminate the Allergan License Agreement if the Company or any of its affiliates or sublicensees institutes a legal challenge to the validity, enforceability, or patentability of the licensed patent rights. Unless terminated earlier in accordance with its terms, the Allergan License Agreement will continue on a country-by-country and product-by-product basis until the later of: (i) the expiration of all of the licensed patent rights in such country; (ii) the expiration of all regulatory exclusivity applicable to the product in such country; and (iii) 10 years from the date of the first commercial sale of the product in such country. As of the date of the Allergan License Agreement, the asset acquired had no alternative future use nor had it reached a stage of technological feasibility. As the processes or activities that were acquired along with the license do not constitute a “business,” the transaction has been accounted for as an asset acquisition. Since the inception of the Allergan License Agreement, the Company achieved certain development and regulatory milestones, resulting in $ 8.0 million in expense, which includes $ 2.0 million paid in the first quarter of 2023. UCB Biopharma Sprl In 2016, the Company entered into a license agreement (the “UCB License Agreement”), as amended from time to time, with UCB Biopharma Sprl (“UCB”), under which UCB granted to the Company a worldwide, sublicensable, exclusive license to UCB6352, which the Company refers to as axatilimab, an anti-CSF-1R monoclonal antibody. Subject to the achievement of certain milestone events, the Company may be required to pay UCB up to $ 119.5 million in one-time development and regulatory milestone payments over the term of the UCB License Agreement. In the event that the Company or any of its affiliates or sublicensees commercializes axatilimab, the Company will also be obligated to pay UCB low double-digit royalties on sales, subject to reduction in certain circumstances, as well as up to an aggregate of $ 250.0 million in potential one-time, sales-based milestone payments based on achievement of certain annual sales thresholds. Under certain circumstances, the Company may be required to share a percentage of non-royalty income from sublicensees, subject to certain deductions, with UCB. The Company is solely responsible for the development and commercialization of axatilimab, except that UCB is performing a limited set of transitional chemistry, manufacturing and control tasks related to axatilimab. Each party may terminate the UCB License Agreement for the other party’s uncured material breach or insolvency, and the Company may terminate the UCB License Agreement at any time upon advance written notice to UCB. UCB may terminate the UCB License Agreement if the Company or any of its affiliates or sublicensees institutes a legal challenge to the validity, enforceability, or patentability of the licensed patent rights. Unless terminated earlier in accordance with its terms, the UCB License Agreement will continue on a country-by-country and product-by-product basis until the later of: (i) the expiration of all of the licensed patent rights in such country; (ii) the expiration of all regulatory exclusivity applicable to the product in such country; and (iii) 10 years from the date of the first commercial sale of the product in such country. As of the date of the UCB License Agreement, the asset acquired had no alternative future use nor had it reached a stage of technological feasibility. As the processes or activities that were acquired along with the license do not constitute a “business,” the transaction has been accounted for as an asset acquisition. As a result, in 2016, the upfront payment of $ 5.0 million was recorded as research and development expense in the consolidated statements of operations. Since the start of the license agreement, the Company achieved certain development and regulatory milestones and has recorded $ 6.0 million as research and development expense. Additionally, in connection with its most recent amendment of the UCB License Agreement, in the second quarter of 2022 the Company paid UCB $ 5.8 million, which is recognized as a milestone expense. Bayer Pharma AG (formerly known as Bayer Schering Pharma AG) In March 2007, the Company entered into a license agreement with Bayer Schering Pharma AG (“Bayer”) for a worldwide, exclusive license to develop and commercialize entinostat and any other products containing the same active ingredient. The Company will pay Bayer royalties on a sliding scale based on net sales, if any, and make future milestone payments to Bayer of up to $ 150.0 million in the event that certain specified development and regulatory goals and sales levels are achieved.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2023
Fair Value Disclosures [Abstract]
Fair Value Measurements	7. Fair Value Measurements The carrying amounts of cash and cash equivalents, restricted cash, accounts payable, and accrued expenses approximated their estimated fair values due to the short-term nature of these financial instruments. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value are performed in a manner to maximize the use of observable inputs and minimize the use of unobservable inputs. The accounting standard describes a fair value hierarchy based on three levels of inputs, of which the first two are considered observable and the last unobservable, that may be used to measure fair value, which are the following: Level 1— Quoted prices (unadjusted) in active markets that are accessible at the market date for identical unrestricted assets or liabilities. Level 2— Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs for which all significant inputs 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 table below presents information about the Company’s assets and liabilities that are regularly measured and carried at fair value and indicate the level within the fair value hierarchy of valuation techniques the Company utilized to determine such fair values (in thousands): Fair Value Measurements Using Quoted Prices Significant (unadjusted) Other Significant Total in Active Observable Unobservable Carrying Markets Inputs Inputs Value (Level 1) (Level 2) (Level 3) (In thousands) March 31, 2023 Assets: Cash and cash equivalents $ 57,517 $ 57,517 $ — $ — Short-term investments 374,876 — 374,876 — Long-term investments 16,561 — 16,561 — Total assets $ 448,954 $ 57,517 $ 391,437 $ — December 31, 2022 Assets: Cash and cash equivalents $ 74,356 $ 59,496 $ 14,860 $ — Short-term investments 401,446 — 401,446 — Long-term investments 5,469 — 5,469 — Total assets $ 481,271 $ 59,496 $ 421,775 $ — There have been no material impairments of our assets measured and carried at fair value during the period ended March 31, 2023 and 2022. In addition, there have been no changes in valuation techniques during the periods ended March 31, 2023 and 2022. The fair value of Level 1 instruments classified as cash equivalents are valued using quoted market prices in active markets. The fair value of Level 2 instruments classified as cash equivalents and short and long–term investments are determined based on quoted prices in active markets, which are either directly or indirectly observable as of the reporting date with fair value being determined using models or other valuation methodologies. The Company's short and long-term investments are classified as available-for-sale securities. As of March 31, 2023, the remaining contractual maturities of the available-for-sale securities were 1 to 15 months, and the balance in the Company’s accumulated other comprehensive loss was comprised solely of activity related to the Company’s available-for-sale securities. There were no realized gains or losses recognized on the sale or maturity of available-for-sale securities, during the three months ended March 31, 2023 and 2022. As a result, the Company did not reclassify any amounts out of accumulated other comprehensive loss for the same periods. The Company has a limited number of available-for-sale securities that are not in significant loss positions as of March 31, 2023, which the Company does not intend to sell, and it has concluded it will not be required to sell before recovery of the amortized cost for the investment at maturity. The following table summarizes the available-for-sale securities: Amortized Unrealized Unrealized Cost Gains Losses Fair Value (In thousands) March 31, 2023 Commercial paper $ 301,633 $ — $ ( 162 ) $ 301,471 US Treasury 39,626 — ( 210 ) 39,416 Federal bonds 50,514 36 — 50,550 $ 391,773 $ 36 $ ( 372 ) $ 391,437 December 31, 2022 Commercial paper $ 321,630 $ — $ ( 205 ) $ 321,425 US Treasury 64,759 — ( 566 ) 64,193 Federal bonds 36,192 — ( 35 ) 36,157 $ 422,581 $ — $ ( 806 ) $ 421,775

Prepaid Expenses and Other Curr

Prepaid Expenses and Other Current Assets	3 Months Ended
	Mar. 31, 2023
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Prepaid Expenses and Other Current Assets	8. Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consisted of the following (in thousands): March 31, 2023 December 31, 2022 Prepaid insurance $ 405 $ 692 Interest receivable on investments 679 583 Prepaid subscription 659 446 Other 170 194 Total prepaid expenses and other current assets $ 1,913 $ 1,915

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	3 Months Ended
	Mar. 31, 2023
Payables And Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	9. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following (in thousands): March 31, 2023 December 31, 2022 Accrued clinical study and trial costs $ 10,627 $ 14,375 Accrued compensation and related costs 3,052 5,945 Accrued professional fees 823 1,352 Accrued milestone costs — 2,000 Other 703 604 Total accrued expenses and other current liabilities $ 15,205 $ 24,276

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2023
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	10. Stock-Based Compensation In January 2023, the number of shares of common stock available for issuance under the Company's 2015 Omnibus Incentive Plan (“2015 Plan”) was increased by 2,724,455 shares due to the automatic annual provision to increase shares available under the 2015 Plan. As of March 31, 2023, the total number of shares of common stock available for issuance under the 2015 Plan was 3,968,714 . The Company recognized stock-based compensation expense related to the issuance of stock option awards to employees and non-employees and related to the Company's 2015 Employee Stock Purchase Plan (“ESPP”) in the condensed consolidated statements of comprehensive loss as follows: Three Months Ended March 31, 2023 2022 Research and development $ 2,778 $ 1,353 General and administrative 3,460 2,125 Total $ 6,238 $ 3,478 Compensation expense by type of award in the three months ended March 31, 2023 and 2022 was as follows: Three Months Ended March 31, 2023 2022 Stock options $ 5,393 $ 2,924 Restricted Stock Units 781 516 Employee Stock Purchase Plan 64 38 Total $ 6,238 $ 3,478 During the three months ended March 31, 2023, the Company granted 1,942,741 stock options to certain executives, consultants and employees having service-based vesting conditions. The grant date fair value of the options granted in the three months ended March 31, 2023, was $ 37.8 million , or $ 19.48 per share on a weighted-average basis and will be recognized as compensation expense over the requisite service period of two to four years. The Company granted to certain employees 140,000 performance-based stock options (“2022 Performance Awards”), in 2022, related to the achievement of certain clinical and regulatory development milestones and market-based conditions. Recognition of stock-based compensation expense associated with these performance-based stock options commences when the performance condition is probable of achievement, using management’s best estimates, which consider the inherent risk and uncertainty regarding the future outcomes of the milestones. In the first quarter of 2022, management estimated one of the milestones, for the 2022 Performance Awards, was probable of achievement and, as such, the Company recorded approximately $ 129,000 and $ 83,000 of stock compensation expense for these awards for the three months ended March 31, 2023 and 2022, respectively. As of March 31, 2023, 140,000 stock options outstanding were unvested, and no options had been canceled. During the three months ended March 31, 2023, 276,506 options were exercised for cash proceeds of approximately $ 2.3 million . During the three months ended March 31, 2022 , 28,839 options were exercised for cash proceeds of $ 465,000 . Restricted stock units RSUs awarded to Board of Directors or employees vest on either i) the one year anniversary date of the related grant or ii) 25% on each anniversary date of the related grant for 4 years. The following table summarizes the Company's RSU activity: Number of Weighted Unvested — December 31, 2022 224,788 $ 18.02 Granted (1) 172,500 $ 28.55 Vested ( 5,000 ) $ 9.47 Unvested—March 31, 2023 (2) 392,288 $ 22.73 (1) RSUs granted in 2023 and 2022 had a weighted average grant date fair value of $ 28.55 and $ 15.79 , respectively. The fair values of RSUs vested in the first quarter of 2023 and 2022 totaled $ 48,000 and $ 36,000 , respectively. (2) Unvested RSUs as of March 31, 2023, include 317,333 RSUs which were granted to members of the Board of Directors and will not be considered issued and outstanding until the occurrence of a separation from service, death, disability, or a change in control. As of March 31, 2023, there were $ 77.8 million of unrecognized compensation costs related to employee and non-employee unvested stock options and RSUs granted under the 2015 and 2007 Plans, which are expected to be recognized over a weighted-average remaining service period of 3.1 years.

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2023
Equity [Abstract]
Stockholders' Equity	11. Stockholders’ Equity The following table presents the changes in stockholders’ equity for the three months ended March 31, 2023: (In thousands, except share data) Common Stock Additional Accumulated Accumulated Total Shares Amount Balance as of December 31, 2022 68,111,385 $ 7 $ 1,161,288 $ ( 806 ) $ ( 693,040 ) $ 467,449 Stock purchase under ESPP 16,537 — — — — — Stock-based compensation expense — — 6,238 — — 6,238 Unrealized gains on investments — — — 470 — 470 Vesting of RSU 5,000 — — — — — Employee withholdings ESPP — — 196 — — 196 Prefunded warrants, exercise 85,998 — — — — — Proceeds from exercise of stock options 276,506 — 2,278 — — 2,278 Net loss — — — — ( 41,126 ) ( 41,126 ) Balance as of March 31, 2023 68,495,426 $ 7 $ 1,170,000 $ ( 336 ) $ ( 734,166 ) $ 435,505 The following table presents the changes in stockholders’ equity for the three months ended March 31, 2022: (In thousands, except share data) Common Stock Additional Accumulated Accumulated Total Shares Amount Balance as of December 31, 2021 54,983,105 $ 6 $ 952,019 $ 45 $ ( 543,702 ) $ 408,368 Stock purchase under ESPP 18,946 — — — — — Stock-based compensation expense — — 3,478 — — 3,478 Unrealized loss on short-term investments — — — ( 685 ) — ( 685 ) Employee withholdings ESPP — — 92 — — 92 Proceeds from exercise of stock options 28,839 — 465 — — 465 Net loss — — — — ( 37,169 ) ( 37,169 ) Balance as of March 31, 2022 55,030,890 $ 6 $ 956,054 $ ( 640 ) $ ( 580,871 ) $ 374,549 In March 2021, the Company entered into a sales agreement with Cowen and Company, LLC (“Cowen”) under which the Company may, from time to time, issue and sell shares of its common stock having aggregate sales proceeds of up to $ 75.0 million, in a series of one or more At-the-Market ("ATM") equity offerings (the “2021 ATM Program”). Cowen is not required to sell any specific share amounts but acts as the Company’s sales agent, using commercially reasonable efforts consistent with its normal trading and sales practices. Shares sold, pursuant to the sales agreement, will be sold pursuant to a shelf registration statement on Form S-3ASR (Registration No. 333-254661), which became automatically effective upon filing on March 24, 2021. The Company’s common stock will be sold at prevailing market prices at the time of the sale; and as a result, prices may vary. For the period ended March 31, 2023, the Company sold no additional shares of common stock under the 2021 ATM Program. In December 2021, the Company issued 3,802,144 shares of common stock and granted pre-funded warrants to purchase 1,142,856 shares of common stock. The offering price for the securities was $ 17.50 per share or $ 17.4999 for each pre-funded warrant, with net proceeds of approximately $ 81.2 million. As of March 31, 2023, 1,056,856 pre-funded warrants were considered issued and outstanding. On April 12, 2023, 273,000 pre-funded warrants were exercised for 272,996 shares of common stock, under a cashless exercise. As of May 3, 2023, 783,856 pre-funded warrants were considered issued and outstanding. In December 2021, in connection with the Incyte License and the Incyte Share Purchase Agreement, the Company issued 1,421,523 shares of common stock, with net proceeds of approximately $ 35.0 million. The Company recorded the equity issuance at a fair value of $ 24.8 million based on the market price of the stock on the date of issuance. In December 2022, the Company issued 7,840,909 shares of common stock in a public offering. The offering price for the securities was $ 22.00 per share, with net proceeds of approximately $ 162.0 million. The Company has reserved for future issuance the following shares of common stock related to the potential warrant exercise, exercise of stock options and the employee stock purchase plan: March 31, 2023 Common stock issuable under pre-funded warrants 1,056,856 Options to purchase common stock 13,897,314 Employee Stock Purchase Plan 1,750,874

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2023
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	12. Commitments and Contingencies From time to time, the Company may be subject to various claims and proceedings in the ordinary course of business. If the potential loss from any claim, asserted or unasserted, or proceeding is considered probable and the amount is reasonably estimable, the Company will accrue a liability for the estimated loss. There were no contingent liabilities recorded as of March 31, 2023

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2023
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies The Company’s significant accounting policies, which are disclosed in the audited consolidated financial statements for the year ended December 31, 2022, and the notes thereto are included in the Company’s Annual Report on Form 10-K that was filed with the SEC on February 28, 2023 . Since the date of filing, there have been no material changes to the Company’s significant accounting policies except as noted below.
Use of Estimates	Use of Estimates The preparation of condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of costs and expenses during the reporting period. The Company bases estimates and assumptions on historical experience when available and on various factors that it believes to be reasonable under the circumstances. The Company evaluates its estimates and assumptions on an ongoing basis. Estimates and assumptions about future events and their effects cannot be determined with certainty and therefore require the exercise of judgment. As of the date of issuance of these financial statements, the Company is not aware of any specific event or circumstance that would require the Company to update its estimates, assumptions and judgments or revise the carrying value of its assets or liabilities. These estimates may change as new events occur and additional information is obtained and are recognized in the consolidated financial statements as soon as they become known. Actual results could differ from those estimates and any such differences may be material to the Company’s condensed consolidated financial statements.
Significant Risks and Uncertainties	Significant Risks and Uncertainties We are subject to challenges and risks specific to our business and our ability to execute on our strategy, as well as risks and uncertainties common to companies in the pharmaceutical industry with development and commercial operations, including, without limitation, risks and uncertainties associated with: obtaining regulatory approval of our late-stage product candidate; delays or problems in the supply of our products, loss of single source suppliers or failure to comply with manufacturing regulations; identifying, acquiring or in-licensing additional products or product candidates; pharmaceutical product development and the inherent uncertainty of clinical success; and the challenges of protecting and enhancing our intellectual property rights; complying with applicable regulatory requirements.
Recently Issued and Adopted Accounting Pronouncements	Recently Issued and Adopted Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (“FASB”) or other accounting standard setting bodies that we adopt as of the specified effective date. Unless otherwise discussed below, we do not believe that the adoption of recently issued standards have or may have a material impact on our consolidated statements or disclosures.

Net Loss per Share Attributab_2

Net Loss per Share Attributable to Common Stockholders (Tables)	3 Months Ended
	Mar. 31, 2023
Earnings Per Share [Abstract]
Computation of Basic and Diluted Net Loss per Share Attributable to Common Stockholders	The following table summarizes the computation of basic and diluted net loss per share attributable to common stockholders of the Company: Three Months Ended March 31, 2023 2022 (In thousands, except share and per Numerator—basic and diluted: Net loss $ ( 41,126 ) $ ( 37,169 ) Net loss attributable to common $ ( 41,126 ) $ ( 37,169 ) Net loss per share attributable to common $ ( 0.59 ) $ ( 0.63 ) Denominator—basic and diluted: Weighted-average number of common shares 69,438,890 58,978,615
Potential Dilutive Securities Excluded from Computation of Diluted Net Loss per Common Share	The following potentially dilutive securities have been excluded from the computation of diluted weighted-average shares outstanding because such securities have an antidilutive impact due to losses reported (in common stock equivalent shares): March 31, 2023 2022 Options to purchase common stock 9,536,312 8,419,541 Employee Stock Purchase Plan 15,331 10,805 Non-vested restricted stock units (RSUs) 392,288 256,583

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2023
Fair Value Disclosures [Abstract]
Schedule of Fair Values of Financial Assets and Liabilities Measured at Fair Value	The table below presents information about the Company’s assets and liabilities that are regularly measured and carried at fair value and indicate the level within the fair value hierarchy of valuation techniques the Company utilized to determine such fair values (in thousands): Fair Value Measurements Using Quoted Prices Significant (unadjusted) Other Significant Total in Active Observable Unobservable Carrying Markets Inputs Inputs Value (Level 1) (Level 2) (Level 3) (In thousands) March 31, 2023 Assets: Cash and cash equivalents $ 57,517 $ 57,517 $ — $ — Short-term investments 374,876 — 374,876 — Long-term investments 16,561 — 16,561 — Total assets $ 448,954 $ 57,517 $ 391,437 $ — December 31, 2022 Assets: Cash and cash equivalents $ 74,356 $ 59,496 $ 14,860 $ — Short-term investments 401,446 — 401,446 — Long-term investments 5,469 — 5,469 — Total assets $ 481,271 $ 59,496 $ 421,775 $ —
Summary of Available-for-Sale Securities	The following table summarizes the available-for-sale securities: Amortized Unrealized Unrealized Cost Gains Losses Fair Value (In thousands) March 31, 2023 Commercial paper $ 301,633 $ — $ ( 162 ) $ 301,471 US Treasury 39,626 — ( 210 ) 39,416 Federal bonds 50,514 36 — 50,550 $ 391,773 $ 36 $ ( 372 ) $ 391,437 December 31, 2022 Commercial paper $ 321,630 $ — $ ( 205 ) $ 321,425 US Treasury 64,759 — ( 566 ) 64,193 Federal bonds 36,192 — ( 35 ) 36,157 $ 422,581 $ — $ ( 806 ) $ 421,775

Prepaid Expenses and Other Cu_2

Prepaid Expenses and Other Current Assets (Tables)	3 Months Ended
	Mar. 31, 2023
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Schedule of Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consisted of the following (in thousands): March 31, 2023 December 31, 2022 Prepaid insurance $ 405 $ 692 Interest receivable on investments 679 583 Prepaid subscription 659 446 Other 170 194 Total prepaid expenses and other current assets $ 1,913 $ 1,915

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	3 Months Ended
	Mar. 31, 2023
Payables And Accruals [Abstract]
Schedule of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consisted of the following (in thousands): March 31, 2023 December 31, 2022 Accrued clinical study and trial costs $ 10,627 $ 14,375 Accrued compensation and related costs 3,052 5,945 Accrued professional fees 823 1,352 Accrued milestone costs — 2,000 Other 703 604 Total accrued expenses and other current liabilities $ 15,205 $ 24,276

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2023
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share Based Compensation Expense Related to Issuance of Stock Option Awards to Employees and Non Employees Related to Employee Stock Purchase Plan	The Company recognized stock-based compensation expense related to the issuance of stock option awards to employees and non-employees and related to the Company's 2015 Employee Stock Purchase Plan (“ESPP”) in the condensed consolidated statements of comprehensive loss as follows: Three Months Ended March 31, 2023 2022 Research and development $ 2,778 $ 1,353 General and administrative 3,460 2,125 Total $ 6,238 $ 3,478
Compensation Expense by Type of Award	Compensation expense by type of award in the three months ended March 31, 2023 and 2022 was as follows: Three Months Ended March 31, 2023 2022 Stock options $ 5,393 $ 2,924 Restricted Stock Units 781 516 Employee Stock Purchase Plan 64 38 Total $ 6,238 $ 3,478
Summary of Restricted Stock Units Activity	RSUs awarded to Board of Directors or employees vest on either i) the one year anniversary date of the related grant or ii) 25% on each anniversary date of the related grant for 4 years. The following table summarizes the Company's RSU activity: Number of Weighted Unvested — December 31, 2022 224,788 $ 18.02 Granted (1) 172,500 $ 28.55 Vested ( 5,000 ) $ 9.47 Unvested—March 31, 2023 (2) 392,288 $ 22.73 (1) RSUs granted in 2023 and 2022 had a weighted average grant date fair value of $ 28.55 and $ 15.79 , respectively. The fair values of RSUs vested in the first quarter of 2023 and 2022 totaled $ 48,000 and $ 36,000 , respectively. (2) Unvested RSUs as of March 31, 2023, include 317,333 RSUs which were granted to members of the Board of Directors and will not be considered issued and outstanding until the occurrence of a separation from service, death, disability, or a change in control.

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2023
Equity [Abstract]
Summary of Changes in Stockholders' Equity	The following table presents the changes in stockholders’ equity for the three months ended March 31, 2023: (In thousands, except share data) Common Stock Additional Accumulated Accumulated Total Shares Amount Balance as of December 31, 2022 68,111,385 $ 7 $ 1,161,288 $ ( 806 ) $ ( 693,040 ) $ 467,449 Stock purchase under ESPP 16,537 — — — — — Stock-based compensation expense — — 6,238 — — 6,238 Unrealized gains on investments — — — 470 — 470 Vesting of RSU 5,000 — — — — — Employee withholdings ESPP — — 196 — — 196 Prefunded warrants, exercise 85,998 — — — — — Proceeds from exercise of stock options 276,506 — 2,278 — — 2,278 Net loss — — — — ( 41,126 ) ( 41,126 ) Balance as of March 31, 2023 68,495,426 $ 7 $ 1,170,000 $ ( 336 ) $ ( 734,166 ) $ 435,505 The following table presents the changes in stockholders’ equity for the three months ended March 31, 2022: (In thousands, except share data) Common Stock Additional Accumulated Accumulated Total Shares Amount Balance as of December 31, 2021 54,983,105 $ 6 $ 952,019 $ 45 $ ( 543,702 ) $ 408,368 Stock purchase under ESPP 18,946 — — — — — Stock-based compensation expense — — 3,478 — — 3,478 Unrealized loss on short-term investments — — — ( 685 ) — ( 685 ) Employee withholdings ESPP — — 92 — — 92 Proceeds from exercise of stock options 28,839 — 465 — — 465 Net loss — — — — ( 37,169 ) ( 37,169 ) Balance as of March 31, 2022 55,030,890 $ 6 $ 956,054 $ ( 640 ) $ ( 580,871 ) $ 374,549
Schedule of Common Stock Reserved for Future Issuance	The Company has reserved for future issuance the following shares of common stock related to the potential warrant exercise, exercise of stock options and the employee stock purchase plan: March 31, 2023 Common stock issuable under pre-funded warrants 1,056,856 Options to purchase common stock 13,897,314 Employee Stock Purchase Plan 1,750,874

Nature of Business - Additional

Nature of Business - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2023 Segment
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Number of operating segments	1
Date of incorporation	Oct. 11, 2005
State of incorporation	DE

Basis of Presentation (Addition

Basis of Presentation (Additional Information) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Accounting Policies [Abstract]
Collaboration receivable, net	$ 2,082	$ (6,260)

Collaborative Research and Li_2

Collaborative Research and License Agreements - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Mar. 31, 2023
Research And Development Arrangement Contract To Perform For Others [Line Items]
Common stock shares purchased	7,840,909	3,802,144
Proceeds from issuance of common stock	$ 162,000	$ 81,200
Collaboration receivable	$ 3,474			$ 1,393
Incyte Agreement [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Common stock shares purchased		1,421,523
Purchase price per share		$ 24.62
Proceeds from issuance of common stock		$ 35,000
Collaboration receivable				3,500
Collaboration expense due to counterparty				$ 2,100
Incyte Agreement [Member] | Maximum [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Potential milestone payments to be made			$ 220,000
Commercialization milestones and tiered royalties			$ 230,000
Incyte Agreement [Member] | Non-Refundable Cash Payments [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Upfront milestone payable		$ 117,000
Global and U.S. [Member] | Incyte Agreement [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Development costs associated with clinical trials			45%
Global and U.S. [Member] | Incyte Agreement [Member] | Incyte Corporation [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Development costs associated with clinical trials			55%
Ex-U.S. Countries [Member] | Incyte Agreement [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Development costs associated with clinical trials			100%

Net Loss per Share Attributab_3

Net Loss per Share Attributable to Common Stockholders - Computation of Basic and Diluted Net Loss per Share Attributable to Common Stockholders (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Numerator—basic and diluted:
Net loss	$ (41,126)	$ (37,169)
Net loss attributable to common stockholders - basic	(41,126)	(37,169)
Net loss attributable to common stockholders - diluted	$ (41,126)	$ (37,169)
Net loss per share attributable to common stockholders—basic	$ (0.59)	$ (0.63)
Net loss per share attributable to common stockholders— diluted	$ (0.59)	$ (0.63)
Denominator—basic and diluted:
Weighted-average number of common shares used to compute net loss per share attributable to common stockholders—basic	69,438,890	58,978,615
Weighted-average number of common shares used to compute net loss per share attributable to common stockholders—diluted	69,438,890	58,978,615

Net Loss per Share Attributab_4

Net Loss per Share Attributable to Common Stockholders - Potential Dilutive Securities Excluded from Computation of Diluted Net Loss per Common Share (Detail) - shares	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Options to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net loss per common share	9,536,312	8,419,541
Employee Stock Purchase Plan [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net loss per common share	15,331	10,805
Non-Vested Restricted Stock Units (RSUs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net loss per common share	392,288	256,583

Net Loss per Share Attributab_5

Net Loss per Share Attributable to Common Stockholders - Additional Information (Detail) - shares	1 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Earnings Per Share Basic [Line Items]
Common stock shares purchased	7,840,909	3,802,144

Significant Agreements - Additi

Significant Agreements - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended			12 Months Ended
	Jul. 31, 2020	Oct. 31, 2017	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2016	Mar. 31, 2007
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Research and development expense			$ 34,054		$ 30,022
Allergan License Agreement Member | Vitae Pharmaceuticals Inc [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Potential milestone payments to be made		$ 99,000
Aggregate potential milestone payable		$ 70,000
License expiration year		10 years
Milestone Expenses Paid			2,000
Development and regulaotry milestones Expenses			$ 8,000
UCB License Agreement [Member] | UCB Biopharma [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Potential milestone payments to be made						$ 119,500
Aggregate potential milestone payable						$ 250,000
License expiration year						10 years
Research and development expense	$ 6,000					$ 5,000
Milestone payment payable				$ 5,800
License Agreement [Member] | Bayer Pharma AG [Member] | Maximum [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Aggregate payment obligation							$ 150,000

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Fair Values of Financial Assets and Liabilities Measured at Fair Value (Detail) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	$ 374,876	$ 401,446
Long-term investments	16,561	5,469
Carrying Value [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents	57,517	74,356
Short-term investments	374,876	401,446
Long-term investments	16,561	5,469
Total assets	448,954	481,271
Quoted Prices (Unadjusted) in Active Markets Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents	57,517	59,496
Total assets	57,517	59,496
Significant Other Observable Inputs Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	14,860
Short-term investments	374,876	401,446
Long-term investments	16,561	5,469
Total assets	$ 391,437	$ 421,775

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Fair Value Measurements [Line Items]
Realized gains or losses recognized on the sale or maturity of available-for-sale securities	$ 0	$ 0

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Available-for-Sale Securities (Detail) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 391,773	$ 422,581
Unrealized Gains	36
Unrealized Losses	(372)	(806)
Fair Value	391,437	421,775
Commercial Paper [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	301,633	321,630
Unrealized Losses	(162)	(205)
Fair Value	301,471	321,425
Federal Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	50,514	36,192
Unrealized Gains	36
Unrealized Losses		(35)
Fair Value	50,550	36,157
U.S. Treasury [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	39,626	64,759
Unrealized Losses	(210)	(566)
Fair Value	$ 39,416	$ 64,193

Prepaid Expenses and Other Cu_3

Prepaid Expenses and Other Current Assets - Schedule of Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Prepaid insurance	$ 405	$ 692
Interest receivable on investments	679	583
Prepaid subscriptions	659	446
Other	170	194
Total prepaid expenses and other current assets	$ 1,913	$ 1,915

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Payables And Accruals [Abstract]
Accrued clinical study and trial costs	$ 10,627	$ 14,375
Accrued compensation and related costs	3,052	5,945
Accrued professional fees	823	1,352
Accrued milestone costs	0	2,000
Other	703	604
Total accrued expenses and other current liabilities	$ 15,205	$ 24,276

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($)	3 Months Ended		123 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2032	Jan. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense, total	$ 6,238,000	$ 3,478,000
Stock options exercised, shares	276,506	28,839
Proceeds from stock option exercises	$ 2,278,000	$ 465,000
2022 Performance Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, stock options vested	140,000
Share-based compensation, stock options cancelled	0
Share based compensation expense, total			$ 129,000
Share based compensation	$ 83,000	83,000
2022 Performance Awards [Member] | Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option granted to certain executives, consultants and employees	140,000
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, stock options vested	317,333
Share based compensation expense, total	$ 781,000	$ 516,000
Fair value of restricted stock units vested	$ 28.55	$ 15.79
Weighted average grant date fair value per share	$ 48,000	$ 36,000
Vesting period, description	the one year anniversary date of the related grant or ii) 25% on each anniversary date of the related grant for 4 years.
2015 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for issuance				2,724,455
2015 Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for issuance	3,968,714
2007 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option granted to certain executives, consultants and employees	1,942,741
Options grant date fair value amount	$ 37,800,000
Weighted average grant date fair value of options	$ 19.48
2015 and 2007 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation	$ 77,800,000
Weighted average period to recognize compensation expense	3 years 1 month 6 days

Stock-Based Compensation - Shar

Stock-Based Compensation - Share Based Compensation Expense Related to Issuance of Stock Option Awards to Employees and Non Employees Related to Employee Stock Purchase Plan (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense, total	$ 6,238	$ 3,478
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense, total	2,778	1,353
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense, total	$ 3,460	$ 2,125

Stock-Based Compensation - Comp

Stock-Based Compensation - Compensation Expense by Type of Award (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense, total	$ 6,238	$ 3,478
Stock options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense, total	5,393	2,924
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense, total	781	516
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense, total	$ 64	$ 38

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Restricted Stock Units Activity (Detail) - $ / shares		3 Months Ended
		Mar. 31, 2023	Mar. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares, Exercised/Released		(276,506)	(28,839)
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Unvested, Beginning balance		224,788
Number of Shares, Granted	[1]	172,500
Number of Shares, Vested		(5,000)
Number of Shares, Unvested, Ending balance	[2]	392,288
Weighted Average Grant Date Fair Value, Unvested, Beginning balance		$ 18.02
Weighted Average Grant Date Fair Value, Granted	[1]	28.55
Weighted Average Grant Date Fair Value, Vested		9.47
Weighted Average Grant Date Fair Value, Unvested, Ending Balance	[2]	$ 22.73
[1] RSUs granted in 2023 and 2022 had a weighted average grant date fair value of $ 28.55 and $ 15.79 , respectively. The fair values of RSUs vested in the first quarter of 2023 and 2022 totaled $ 48,000 and $ 36,000 , respectively. Unvested RSUs as of March 31, 2023, include 317,333 RSUs which were granted to members of the Board of Directors and will not be considered issued and outstanding until the occurrence of a separation from service, death, disability, or a change in control.

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Restricted Stock Units Activity (Detail) (Parenthetical) - Restricted Stock Units [Member] - USD ($)		3 Months Ended
		Mar. 31, 2023	Mar. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Fair value of restricted stock units vested		$ 28.55	$ 15.79
Weighted average grant date fair value per share		$ 48,000	$ 36,000
Share-based compensation, stock options vested		317,333
Number of Shares, Unvested, Ending balance	[1]	392,288
[1] Unvested RSUs as of March 31, 2023, include 317,333 RSUs which were granted to members of the Board of Directors and will not be considered issued and outstanding until the occurrence of a separation from service, death, disability, or a change in control.

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Changes in Stockholders' Equity (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Class of Stock [Line Items]
Beginning balance	$ 467,449	$ 408,368
Stock-based compensation expense	6,238	3,478
Unrealized (loss) gain on marketable securities	470	(685)
Employee withholdings ESPP	196	92
Proceeds from exercise of stock options	$ 2,278	$ 465
Proceeds from exercise of stock options, shares	276,506	28,839
Net loss	$ (41,126)	$ (37,169)
Ending balance	435,505	374,549
Common Stock [Member]
Class of Stock [Line Items]
Beginning balance	$ 7	$ 6
Beginning balance, shares	68,111,385	54,983,105
Stock purchase under ESPP, shares	16,537	18,946
Vesting of RSU, shares	5,000
Prefunded warrants, exercise, shares	85,998
Proceeds from exercise of stock options, shares	276,506	28,839
Ending balance	$ 7	$ 6
Ending balance, shares	68,495,426	55,030,890
Additional Paid-In Capital [Member]
Class of Stock [Line Items]
Beginning balance	$ 1,161,288	$ 952,019
Stock-based compensation expense	6,238	3,478
Employee withholdings ESPP	196	92
Proceeds from exercise of stock options	2,278	465
Ending balance	1,170,000	956,054
Accumulated Other Comprehensive(Loss) / Income [Member]
Class of Stock [Line Items]
Beginning balance	(806)	45
Unrealized (loss) gain on marketable securities	470	(685)
Ending balance	(336)	(640)
Accumulated Deficit [Member]
Class of Stock [Line Items]
Beginning balance	(693,040)	(543,702)
Net loss	(41,126)	(37,169)
Ending balance	$ (734,166)	$ (580,871)

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended			3 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Mar. 31, 2023	May 03, 2023	Apr. 12, 2023
Class Of Stock [Line Items]
Proceeds from issuance of common stock	$ 162	$ 81.2
Common stock, new shares issued	7,840,909	3,802,144
Offering price	$ 22
Subsequent Event [Member]
Class Of Stock [Line Items]
Number of pre funded warrants exercised for common stock						272,996
Incyte Collaboration Agreement and Share Purchase Agreement [Member]
Class Of Stock [Line Items]
Proceeds from issuance of common stock		$ 35
Common stock, new shares issued		1,421,523
Common stock issued at fair value		$ 24.8
At The Market Equity Offering Sales Agreement [Member]
Class Of Stock [Line Items]
Common stock, new shares issued				0
Pre Funded Warrants [Member]
Class Of Stock [Line Items]
Warrants issued (in shares)		1,142,856
Offering price		$ 17.4999
Shares available for issuance				1,056,856
Pre Funded Warrants [Member] | Subsequent Event [Member]
Class Of Stock [Line Items]
Number of pre funded warrants exercised for common stock						273,000
Warrants Outstanding					783,856
Series Warrants [Member]
Class Of Stock [Line Items]
Offering price		$ 17.50
Cowen and Company LLC [Member] | At The Market Equity Offering Sales Agreement [Member]
Class Of Stock [Line Items]
Proceeds from issuance of common stock			$ 75

Stockholders' Equity - Schedule

Stockholders' Equity - Schedule of Common Stock Reserved for Future Issuance (Detail)	Mar. 31, 2023 shares
Pre Funded Warrants [Member]
Class Of Stock [Line Items]
Common Stock Capital Shares Reserved For Future Issuance	1,056,856
Options to Purchase Common Stock [Member]
Class Of Stock [Line Items]
Common Stock Capital Shares Reserved For Future Issuance	13,897,314
Employee Stock Purchase Plan [Member]
Class Of Stock [Line Items]
Common Stock Capital Shares Reserved For Future Issuance	1,750,874

Commitments and Contingencies (

Commitments and Contingencies (Additional Information) (Details) $ in Thousands	Mar. 31, 2023 USD ($)
Commitments And Contingencies Disclosure [Abstract]
Contingent liabilities	$ 0