Nuvalent (NUVL) 10-Q 10 Nov 21 2021 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2021	Oct. 31, 2021
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Sep. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31
Entity File Number	001-40671
Entity Registrant Name	NUVALENT, INC.
Entity Central Index Key	0001861560
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	83-5112298
Entity Address, Address Line One	One Broadway
Entity Address, Address Line Two	14th Floor
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02142
City Area Code	857
Local Phone Number	357-7000
Title of 12(b) Security	Class A Common stock, par value $0.0001 per share
Trading Symbol	NUVL
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Common Class A [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		42,848,715
Common Class B [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		5,435,254

BALANCE SHEETS

BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 245,886	$ 10,332
Marketable securities	56,543	0
Prepaid expenses and other current assets	2,710	314
Total current assets	305,139	10,646
Other assets	2,834
Total assets	307,973	10,646
Current liabilities:
Accounts payable	2,532	1,252
Accrued expenses	4,310	1,171
Preferred stock tranche rights		1,957
Total current liabilities	6,842	4,380
Notes payable and accrued interest to stockholder		2,235
Total liabilities	6,842	6,615
Commitments and contingencies (Note 10 )
Convertible preferred stock (Series A and B), $0.0001 par value; no shares and 112,431,508 shares authorized at September 30, 2021 and December 31, 2020, respectively; no shares and 89,945,206 shares issued and outstanding at September 30, 2021 and December 31, 2020, respectively;		35,354
Stockholders' equity (deficit):
Preferred stock, $0.0001 par value; 10,000,000 shares and no shares authorized at September 30, 2021 and December 31, 2020, respectively; no shares issued or outstanding
Additional paid-in capital	362,083	842
Accumulated other comprehensive loss	(23)
Accumulated deficit	(60,934)	(31,885)
Promissory note from stockholder		(280)
Total stockholders' equity (deficit)	301,131	(31,323)
Total liabilities, convertible preferred stock and stockholders' equity (deficit)	307,973	$ 10,646
Common Class A [Member]
Stockholders' equity (deficit):
Common stock	4
Common Class B [Member]
Stockholders' equity (deficit):
Common stock	$ 1

BALANCE SHEETS (Parenthetical)

BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2021	Dec. 31, 2020
Temporary equity, shares authorized		112,431,508
Temporary equity, shares issued		89,945,206
Temporary equity, shares outstanding		89,945,206
Preferred stock, par value | $ / shares	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	10,000,000	0
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Convertible preferred stock [Member]
Temporary equity, par or stated value per share	$ 0.0001	$ 0.0001
Temporary equity, shares authorized	0	112,431,508
Temporary equity, shares issued	0	89,945,206
Temporary equity, shares outstanding	0	89,945,206
Common Class A [Member]
Common stock, par value | $ / shares	$ 0.0001	$ 0.0001
Common stock, shares authorized	140,000,000	160,000,000
Common stock, shares issued	42,848,715	3,129,384
Common stock, shares outstanding	42,848,715	3,129,384
Common Class B [Member]
Common stock, par value | $ / shares	$ 0.0001	$ 0.0001
Common stock, shares authorized	10,000,000	0
Common stock, shares issued	5,435,254	0
Common stock, shares outstanding	5,435,254	0

STATEMENTS OF OPERATIONS AND CO

STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Operating expenses:
Research and development	$ 9,055	$ 3,721	$ 22,365	$ 10,704
General and administrative	3,372	319	6,074	987
Total operating expenses	12,427	4,040	28,439	11,691
Loss from operations	(12,427)	(4,040)	(28,439)	(11,691)
Other income (expense):
Change in fair value of preferred stock tranche rights		(724)	(635)	3,747
Other income (expense), net	1	(14)	25	(32)
Total other income (expense), net	1	(738)	(610)	3,715
Net loss	$ (12,426)	$ (4,778)	$ (29,049)	$ (7,976)
Net loss per share attributable to common stockholders, basic	$ (0.39)	$ (1.57)	$ (2.26)	$ (2.85)
Net loss per share attributable to common stockholders, diluted	$ (0.39)	$ (1.57)	$ (2.26)	$ (2.85)
Weighted average shares of common stock outstanding, basic	32,066,089	3,042,398	12,858,574	2,798,910
Weighted average shares of common stock outstanding, diluted	32,066,089	3,042,398	12,858,574	2,798,910
Comprehensive loss:
Net loss	$ (12,426)	$ (4,778)	$ (29,049)	$ (7,976)
Other comprehensive loss:
Unrealized losses on marketable securities, net of tax of $0	(23)		(23)
Comprehensive loss	$ (12,449)	$ (4,778)	$ (29,072)	$ (7,976)

STATEMENTS OF OPERATIONS AND _2

STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (Parenthetical) $ in Thousands	9 Months Ended
	Sep. 30, 2021USD ($)
Income Statement [Abstract]
Unrealized losses on marketable securities, tax	$ 0

STATEMENTS OF CONVERTIBLE PREFE

STATEMENTS OF CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Convertible preferred stock [Member]	Common stock [Member]	Common stock [Member]Common Class A [Member]	Common stock [Member]Common Class B [Member]	Additional paid-in capital [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated deficit [Member]	Promissory note from stockholder [Member]
Beginning Balance , Shares at Dec. 31, 2019		39,351,028
Beginning Balance at Dec. 31, 2019		$ 14,048
Beginning Balance , Shares at Dec. 31, 2019				2,138,988
Beginning Balance at Dec. 31, 2019	$ (17,256)					$ 98		$ (17,329)	$ (25)
Issuance of convertible preferred stock , Shares		28,107,876
Issuance of convertible preferred stock		$ 12,500
Stock-based compensation expense	623					623
Reclassification of preferred stock tranche rights upon settlement		$ (1,538)
Net loss	5,359							5,359
Ending Balance , Shares at Mar. 31, 2020		67,458,904
Ending Balance at Mar. 31, 2020		$ 25,010
Ending Balance , Shares at Mar. 31, 2020				2,138,988
Ending Balance at Mar. 31, 2020	(11,274)					721		(11,970)	(25)
Beginning Balance , Shares at Dec. 31, 2019		39,351,028
Beginning Balance at Dec. 31, 2019		$ 14,048
Beginning Balance , Shares at Dec. 31, 2019				2,138,988
Beginning Balance at Dec. 31, 2019	(17,256)					98		(17,329)	(25)
Reclassification of preferred stock tranche rights upon settlement	(1,194)
Net loss	(7,976)
Ending Balance , Shares at Sep. 30, 2020		89,945,206
Ending Balance at Sep. 30, 2020		$ 35,354
Ending Balance , Shares at Sep. 30, 2020				3,091,728
Ending Balance at Sep. 30, 2020	(24,798)					785		(25,305)	(278)
Beginning Balance , Shares at Dec. 31, 2019		39,351,028
Beginning Balance at Dec. 31, 2019		$ 14,048
Beginning Balance , Shares at Dec. 31, 2019				2,138,988
Beginning Balance at Dec. 31, 2019	(17,256)					98		(17,329)	(25)
Net loss	$ (14,600)
Ending Balance , Shares at Dec. 31, 2020	89,945,206	89,945,206
Ending Balance at Dec. 31, 2020	$ 35,354	$ 35,354
Ending Balance , Shares at Dec. 31, 2020				3,129,384
Ending Balance at Dec. 31, 2020	(31,323)					842		(31,885)	(280)
Beginning Balance , Shares at Mar. 31, 2020		67,458,904
Beginning Balance at Mar. 31, 2020		$ 25,010
Beginning Balance , Shares at Mar. 31, 2020				2,138,988
Beginning Balance at Mar. 31, 2020	(11,274)					721		(11,970)	(25)
Issuance of common stock				952,740
Stock-based compensation expense	29					29
Interest on promissory note from related stockholder party	(1)								(1)
Issuance of promissory note from related party stockholder	(250)								(250)
Net loss	(8,557)							(8,557)
Ending Balance , Shares at Jun. 30, 2020		67,458,904
Ending Balance at Jun. 30, 2020		$ 25,010
Ending Balance , Shares at Jun. 30, 2020				3,091,728
Ending Balance at Jun. 30, 2020	(20,053)					750		(20,527)	(276)
Issuance of convertible preferred stock , Shares		22,486,302
Issuance of convertible preferred stock		$ 10,000
Stock-based compensation expense	35					35
Interest on promissory note from related stockholder party	(2)								(2)
Reclassification of preferred stock tranche rights upon settlement		$ 344
Net loss	(4,778)							(4,778)
Ending Balance , Shares at Sep. 30, 2020		89,945,206
Ending Balance at Sep. 30, 2020		$ 35,354
Ending Balance , Shares at Sep. 30, 2020				3,091,728
Ending Balance at Sep. 30, 2020	$ (24,798)					785		(25,305)	(278)
Beginning Balance , Shares at Dec. 31, 2020	89,945,206	89,945,206
Beginning Balance at Dec. 31, 2020	$ 35,354	$ 35,354
Beginning Balance , Shares at Dec. 31, 2020				3,129,384
Beginning Balance at Dec. 31, 2020	(31,323)					842		(31,885)	(280)
Issuance of convertible preferred stock , Shares		22,486,302
Issuance of convertible preferred stock		$ 10,000
Conversion of note payable and accrued interest to Series A convertible preferred stock , Shares		5,025,604
Conversion of note payable and accrued interest to Series A convertible preferred stock		$ 2,815
Stock-based compensation expense	65					65
Interest on promissory note from related stockholder party	(2)								(2)
Reclassification of preferred stock tranche rights upon settlement		$ 2,592
Loss on extinguishment of debt	(580)					(580)
Net loss	(6,785)							(6,785)
Ending Balance , Shares at Mar. 31, 2021		117,457,112
Ending Balance at Mar. 31, 2021		$ 50,761
Ending Balance , Shares at Mar. 31, 2021				3,129,384
Ending Balance at Mar. 31, 2021	$ (38,625)					327		(38,670)	(282)
Beginning Balance , Shares at Dec. 31, 2020	89,945,206	89,945,206
Beginning Balance at Dec. 31, 2020	$ 35,354	$ 35,354
Beginning Balance , Shares at Dec. 31, 2020				3,129,384
Beginning Balance at Dec. 31, 2020	(31,323)					842		(31,885)	(280)
Reclassification of preferred stock tranche rights upon settlement	2,592
Loss on extinguishment of debt	(580)
Net loss	(29,049)
Ending Balance , Shares at Sep. 30, 2021		0
Ending Balance , Shares at Sep. 30, 2021				42,848,715	5,435,254
Ending Balance at Sep. 30, 2021	301,131			$ 4	$ 1	362,083	$ (23)	(60,934)
Beginning Balance , Shares at Mar. 31, 2021		117,457,112
Beginning Balance at Mar. 31, 2021		$ 50,761
Beginning Balance , Shares at Mar. 31, 2021				3,129,384
Beginning Balance at Mar. 31, 2021	(38,625)					327		(38,670)	(282)
Issuance of convertible preferred stock , Shares		65,223,679
Issuance of convertible preferred stock		$ 134,652
Stock-based compensation expense	725					725
Interest on promissory note from related stockholder party	(2)								(2)
Net loss	(9,838)							(9,838)
Ending Balance , Shares at Jun. 30, 2021		182,680,791
Ending Balance at Jun. 30, 2021		$ 185,413
Ending Balance , Shares at Jun. 30, 2021			3,129,384
Ending Balance at Jun. 30, 2021	(47,740)					1,052		(48,508)	(284)
Conversion of preferred stock to common stock upon initial public offering, Shares		(182,680,791)		29,106,831	4,835,254
Conversion of preferred stock to common stock upon initial public offering	185,413	$ (185,413)		$ 3	$ 1	185,409
Issuance of common stock				10,612,500	600,000
Issuance of common stock upon initial public offering, net of issuance costs	174,250			$ 1		174,249
Stock-based compensation expense	1,373					1,373
Repayment of promissory note from related stockholder party	284								$ 284
Unrealized losses on marketable securities	(23)						(23)
Net loss	(12,426)							(12,426)
Ending Balance , Shares at Sep. 30, 2021		0
Ending Balance , Shares at Sep. 30, 2021				42,848,715	5,435,254
Ending Balance at Sep. 30, 2021	$ 301,131			$ 4	$ 1	$ 362,083	$ (23)	$ (60,934)

STATEMENTS OF CONVERTIBLE PRE_2

STATEMENTS OF CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2021	Jun. 30, 2021
Series B convertible preferred stock [Member]
Temporary Equity Issuance Costs		$ 348
Common Stock [Member]
Stock Issuance Costs	$ 3,020

STATEMENTS OF CASH FLOWS

STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities:
Net loss	$ (29,049)	$ (7,976)
Adjustments to reconcile net loss to net cash used in operating activities:
Change in fair value of preferred stock tranche rights	635	(3,747)
Stock-based compensation expense	2,163	687
Non-cash interest income on promissory note	(4)	(3)
Net amortization of premiums on marketable securities	1
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(444)	(275)
Other assets	(2,834)
Accounts payable	909	187
Accrued expenses	1,578	1,115
Net cash used in operating activities	(27,045)	(10,012)
Cash flows from investing activities:
Purchases of marketable securities	(56,567)
Net cash used in investing activities	(56,567)
Cash flows from financing activities:
Proceeds from issuance of convertible preferred stock and preferred stock tranche rights, net of issuance costs	144,652	22,500
Proceeds from initial public offering, net of underwriting discounts and commissions	177,270
Issuance of promissory note to stockholder		(250)
Payments of insurance costs financed by a third-party	(391)
Proceeds from repayment of promissory note to stockholder	284
Payments of initial public offering costs	(2,649)
Net cash provided by financing activities	319,166	22,250
Net increase in cash and cash equivalents	235,554	12,238
Cash and cash equivalents at beginning of period	10,332	3,016
Cash and cash equivalents at end of period	245,886	15,254
Supplemental disclosure of noncash financing information:
Settlement of notes payable and accrued interest for preferred stock	2,235
Conversion of convertible preferred stock to common stock upon initial public offering	185,413
Insurance premium financed by a third-party	1,952
Loss on extinguishment of debt	580
Settlement of preferred stock tranche rights	2,592	$ (1,194)
Initial public offering costs in accounts payable	$ 371

Nature of Business and Basis of

Nature of Business and Basis of Presentation	9 Months Ended
	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Business and Basis of Presentation	1. Nature of Business and Basis of Presentation Nuvalent, Inc. (the “Company”) is a biopharmaceutical company focused on creating precisely targeted therapies for patients with cancer, designed to overcome the limitations of existing therapies for clinically proven kinase targets. The Company was founded in January 2017 as a Delaware corporation. The Company is headquartered in Cambridge, Massachusetts. The Company is subject to risks similar to those of other pre-commercial COVID-19 . In March 2020, the World Health Organization declared the COVID-19 COVID-19 COVID-19 COVID-19 COVID-19 On July 23, 2021, the Company effected a one-for-5.38213 On July 23, 2021, the Company filed an amendment to its amended and restated certificate of incorporation, which effected a recapitalization of the Company’s then outstanding common stock to Class A common stock and authorized an additional new class of common stock (“Class B common stock”). The rights of the holders of Class A common stock and Class B common stock are substantially identical, except with respect to voting and conversion. Each share of Class A common stock is entitled to one vote and shares of Class B common stock are non-voting, On August 2, 2021, the Company completed an initial public offering (“IPO”) of its common stock and issued and sold 10,612,500 shares of Class A and 600,000 shares of Class B common stock at a public offering price of $17.00 per share, inclusive of 1,462,500 shares of Class A common stock pursuant to the full exercise of the underwriters’ option to purchase additional shares. The Company received net proceeds of approximately $174.3 million after deducting underwriting discounts and commissions and offering costs. In connection with the IPO, the Company’s outstanding convertible preferred stock automatically converted into shares of Class A and Class B common stock. Basis of presentation The Company’s financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”). Since its inception, the Company has funded its operations primarily with proceeds from sales of preferred stock, issuance of convertible notes (which converted in 2018), debt financing from its investors (which was settled with convertible preferred stock in February 2021), and most recently, with proceeds from the sale of common stock in the IPO completed in August 2021. The Company has incurred recurring losses since inception, including net losses of $29.0 million for the nine months ended September 30, 2021 and $14.6 million for the year ended December 31, 2020. As of September 30, 2021, the Company had an accumulated deficit of $60.9 million. The Company expects to continue to generate operating losses for the foreseeable future. The Company believes that its existing cash, cash equivalents and marketable securities will be sufficient to fund its operating expenses and capital expenditure requirements for at least 12 months from the date of issuance of these financial statements. The Company will need to obtain additional funding through public or private equity offerings, debt financings or strategic alliances. The Company may not be able to obtain financing on acceptable terms, or at all, and the Company may not be able to enter into strategic alliances. The terms of any financing may adversely affect the holdings or the rights of the Company’s stockholders. Arrangements with collaborators or others may require the Company to relinquish rights to certain of its technologies or programs. If the Company is unable to obtain funding, the Company will be required to delay, reduce or eliminate some or all of its research and development programs or the Company may be unable to continue operations. Although management will continue to pursue these plans, there is no assurance that the Company will be successful in obtaining sufficient funding on terms acceptable to the Company to fund continuing operations when needed or at all.​​​​​​​

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Use of estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting periods. Significant estimates and assumptions reflected in these financial statements include, but are not limited to, the valuation of common stock, the valuation of stock-based awards, preferred stock tranche rights and the accrual of research and development expenses. The Company bases its estimates on historical experience, known trends and other market-specific or other relevant factors that it believes to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates as there are changes in circumstances, facts and experience. Actual results may differ from those estimates or assumptions. Unaudited interim financial information The balance sheet at December 31, 2020 was derived from audited financial statements but does not include all disclosures required by GAAP. The accompanying unaudited financial statements as of September 30, 2021 and for the three and nine months ended September 30, 2021 and 2020 have been prepared by the Company pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim financial statements. Certain information and footnote disclosures normally included in the financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. These financial statements should be read in conjunction with the Company’s audited financial statements and the notes thereto for the year ended December 31, 2020 included in the Company’s Registration Statement on Form S-1, No. 333-257730 Concentrations of credit risk and of significant suppliers Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash, cash equivalents and marketable securities. As of September 30, 2021 and December 31, 2020, the Company maintained cash, cash equivalents and marketable securities balances in excess of federally insured limits. The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. The Company is dependent on third-party vendors for the manufacturing of its product candidates. In particular, the Company relies, and expects to continue to rely, on a small number of vendors to manufacture materials and components required for the production of its product candidates. These programs could be adversely affected by a significant interruption in the manufacturing process. Fair value measurements Certain assets and liabilities are carried at fair value under GAAP. 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 must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable: • Level 1—Quoted prices in active markets for identical assets or liabilities. • Level 2—Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data. • Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques. The Company’s cash equivalents and marketable securities are carried at fair value, determined according to the fair value hierarchy described above (see Note 4). The carrying values of the Company’s accounts payable and accrued expenses approximate their fair values due to the short-term nature of these liabilities . Marketable securities The Company’s marketable securities (non-equity available-for-sale . The Company evaluates its marketable securities with unrealized losses for other-than-temporary impairment. When assessing marketable securities for other-than-temporary declines in value, the Company considers 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, 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. If any adjustment to fair value reflects a decline in the value of the investment that the Company considers to be “other than temporary,” the Company reduces the investment to fair value through a charge recorded in the statements of operations. No such adjustments were necessary during the periods presented. The Company classifies its marketable securities with maturities beyond one year as short-term, based on their highly liquid nature and because such marketable securities are available for current operations. Research and development costs Research and development expenses consist of costs incurred in performing research and development activities, including salaries and bonuses, stock-based compensation, employee benefits, consulting costs, and external costs of vendors engaged to conduct research, preclinical and clinical development activities. Costs for research and development activities are expensed in the period in which they are incurred. Payments for such activities are based on the terms of the individual arrangements, which may differ from the pattern of costs incurred, and are reflected in the financial statements as prepaid expense or accrued research and development expense. Determining the prepaid and accrued balances at the end of any reporting period incorporates certain judgments and estimates by management that are based on information available to the Company including information provided by vendors regarding the progress to completion of specific tasks or costs incurred. Stock-based compensation The Company measures stock options with service-based vesting granted to employees, non-employees The Company classifies stock-based compensation expense in its statements of operations and comprehensive loss in the same manner in which the award recipient’s payroll costs are classified or in which the award recipient’s service payments are classified. Net income (loss) per share Prior to the closing of the IPO, the Company followed the two-class method The two-class method The two-class method Subsequent to the closing of its IPO, basic net income (loss) per common share is computed by dividing the net income (loss) by the weighted average number of shares of common stock outstanding for the period. Diluted net income (loss) per common share is computed by dividing net income (loss) by the weighted average number of common shares outstanding for the period, including potential dilutive common shares assuming the dilutive effect of outstanding stock options and unvested restricted stock units. For periods in which the Company reported a net loss, diluted net loss per common share is the same as basic net loss per common share, since dilutive common shares are not assumed to have been issued if their affect is anti-dilutive. The Company has two classes of common stock outstanding: Class A common stock and Class B common stock. As more fully described in Note 8, the rights of the holders of Class A and Class B common stock are substantially identical, except with respect to voting and conversion. Each share of Class B common stock is convertible into one share of Class A common stock at the option of the holder at any time, subject to the ownership limitations provided for in the Company’s amended and restated certificate of incorporation. The Company allocates undistributed earnings attributable to common stock between the common stock classes on a one-to-one The Company excluded the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common stockholders for the three and nine months ended September 30, 2021 and 2020 because including them would have had an anti-dilutive effect: As of September 30, 2021 2020 Convertible preferred stock (as converted to common stock) — 16,711,823 Unvested restricted common stock 21,129 48,039 Options to purchase common stock 4,748,605 1,104,832 4,769,734 17,864,694 Recently issued accounting pronouncements The Company qualifies as an “emerging growth company” as defined in the JOBS Act and has elected not to “opt out” of the extended transition related to complying with new or revised accounting standards, which means that when a standard is issued or revised and it has different application dates for public and nonpublic companies, the Company will adopt the new or revised standard at the time nonpublic companies adopt the new or revised standard and will do so until such time that the Company either (i) irrevocably elects to “opt out” of such extended transition period or (ii) no longer qualifies as an emerging growth company. In February 2016, the FASB issued ASU No. 2016-02, 2016-02”), right-of-use 2016-02, 2018-10, 2018-11, No. 2020-05, one-year right-of-use In June 2016, the FASB issued ASU No. 2016-13, No. 2019-10,

Marketable Securities

Marketable Securities	9 Months Ended
	Sep. 30, 2021
Marketable Securities [Abstract]
Marketable Securities	3. Marketable Securities Marketable securities by security type consisted of the following (in thousands): September 30, 2021 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Commercial paper (due within one year) $ 46,269 $ — $ (17 ) $ 46,252 Corporate bonds (due within one year) 8,257 — (4 ) 8,253 Corporate bonds (due after one year through two years) 2,040 — (2 ) 2,038 $ 56,566 $ — $ (23 ) $ 56,543 The Company had no marketable securities as of December 31, 2020 .

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. Fair Value Measurements The following tables present the Company’s fair value hierarchy for its assets and liabilities, which are measured at fair value on a recurring basis (in thousands): Fair Value Measurements at September 30, 2021 Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 239,383 $ — $ — $ 239,383 Commercial paper — 5,499 — 5,499 Marketable securities: Corporate bonds — 10,291 — 10,291 Commercial paper — 46,252 — 46,252 $ 239,383 $ 62,042 $ — $ 301,425 Fair Value Measurements at December 31, Level 1 Level 2 Level 3 Total Liabilities: Preferred stock tranche rights $ — $ — $ 1,957 $ 1,957 Money market funds were valued by the Company based on quoted market prices, which represent a Level 1 measurement within the fair value hierarchy. Corporate bonds and commercial paper were valued by the Company using quoted prices in active markets for similar securities, which represent a Level 2 measurement within the fair value hierarchy. During the three and nine months ended September 30, 2021 and 2020, there were no transfers in or out of Level 3. The following table provides a roll-forward of the aggregate fair values of the Company’s preferred stock tranche rights, for which fair value was determined by Level 3 inputs (in thousands): Preferred Stock Fair value at December 31, 2020 $ 1,957 Change in fair value 635 Settlement of preferred stock tranche rights (2,592 ) Fair value at September 30, 2021 $ — The preferred stock tranche rights represented the fair value of the rights and obligations of the original purchasers of the Series A convertible preferred stock to participate in subsequent closings of Series A convertible preferred stock upon the achievement of certain strategic milestones or as determined by the Series A investors (the “Series A Tranche Rights”), which were fully settled by March 31, 2021. The Series A Tranche Rights met the definition of a freestanding financial instrument as the Series A Tranche Rights were legally detachable and separately exercisable from the Series A convertible preferred stock. The fair value of the Series A Tranche Rights were initially classified as a liability and recorded at fair value and were subject to revaluation at each balance sheet date until each Series A Tranche Right was exercised. The fair values of the Series A Tranche Rights were based on significant inputs not observable in the market, which represented a Level 3 measurement within the fair value hierarchy. The Company’s valuation of the Series A Tranche Rights utilized a scenario-based valuation analysis, which incorporated assumptions and estimates to value the Series A Tranche Rights and a probability assessment of the achievement of the milestones. The Company assessed these assumptions and estimates at the end of each reporting period as additional information impacting the assumptions were obtained. The quantitative elements associated with the Company’s Level 3 inputs impacting the fair value measurement of the Series A Tranche Rights included the fair value per share of the underlying convertible preferred stock, the expected term of the Series A Tranche Rights, risk-free interest rate, expected dividend yield and expected volatility of the price of the underlying convertible preferred stock. The Company determined the fair value per share of the underlying convertible preferred stock by taking into consideration its most recent sales of its convertible preferred stock as well as additional factors that the Company deemed relevant. The Company historically has been a private company and lacks company-specific historical and implied volatility information of its stock. Therefore, it estimated its expected stock volatility based on the historical volatility of a representative group of public companies in the biotechnology industry for the expected terms. The risk-free interest rate was determined by reference to the U.S. Treasury yield curve for time periods approximately equal to the expected terms. The Company estimated a 0% dividend yield based on the expected dividend yield and the fact that the Company has never paid or declared dividends. The Company assessed the probabilities of achieving the milestones related to each tranche upon issuance and at the end of each reporting period. Probabilities ranged from 90.0% to 100.0% and expected terms ranged from 0.2 years to 1.6 years. As of December 31, 2020, the fair value of the Company’s Series A convertible preferred stock was $0.53 per share. The Series A Tranche Rights were exercised in March 2020, August 2020 and February 2021. All Series A Tranche Rights were settled by March 31, 2021.

Accrued Expenses

Accrued Expenses	9 Months Ended
	Sep. 30, 2021
Accrued Liabilities, Current [Abstract]
Accrued Expenses	5. Accrued Expenses Accrued expenses consisted of the following (in thousands): September 30, 2021 December 31, 2020 Accrued employee compensation and benefits $ 1,679 $ 636 Accrued external research and development expenses 880 405 Accrued professional fees 1,751 103 Other — 27 $ 4,310 $ 1,171

Notes Payable to Related Party

Notes Payable to Related Party	9 Months Ended
	Sep. 30, 2021
Related Party Transactions [Abstract]
Notes Payable to Related Party	6. Notes Payable to Related Party In February 2017, the Company issued $2.0 million of promissory notes (the “Notes”) to Deerfield Healthcare Innovations Fund, L.P. and Deerfield Private Design Fund, IV, L.P. (collectively “Deerfield”), an investor in the Company. The Notes accrued interest at a rate of 2.81% per annum, compounded annually, and matured upon the earlier of a change in control event as defined in the Company’s charter or five years from issuance. In connection with the issuance of the Notes, the Company entered into a revenue share agreement with Deerfield for contingent payments of a low single digit percentage rate of net sales of commercial product (see Note 10). In February 2021, the Company issued 5,025,604 shares of Series A convertible preferred stock in full settlement of the Notes and accrued interest. The issuance of the Series A convertible preferred stock was recorded at fair value and as a result, the Company recorded a loss on extinguishment of debt of $0.6 million upon the conversion representing the difference between the carrying value of the Notes and the fair value of the Series A convertible preferred stock. The loss on extinguishment of debt was recognized as additional paid-in capital, a component of stockholders’ equity (deficit), due to the related party nature of the Notes.

Convertible Preferred Stock

Convertible Preferred Stock	9 Months Ended
	Sep. 30, 2021
Stockholders' Equity Note [Abstract]
Convertible Preferred Stock	7. Convertible Preferred Stock The Company had issued Series A convertible preferred stock (the “Series A”) and Series B convertible preferred stock (the “Series B”). The Series A and Series B are collectively referred to as the “Preferred Stock”. Preferred Stock consisted of the following as of December 31, 2020: Preferred Preferred Stock Carrying Value Liquidation Common Stock (in thousands) (in thousands) Series A Preferred Stock 112,431,508 89,945,206 $ 35,354 $ 40,000 16,711,823 112,431,508 89,945,206 $ 35,354 $ 40,000 16,711,823 In April 2021, the Company issued and sold 65,223,679 shares of Series B at a price of $2.0698 per share, for gross proceeds of $135.0 million. There were no tranche rights granted in connection with the Series B issuance and sale. Upon the closing of the IPO, all of the shares of the Company’s outstanding Preferred Stock automatically converted into shares of Class A and Class B common stock.

Common Stock

Common Stock	9 Months Ended
	Sep. 30, 2021
Equity [Abstract]
Common Stock	8. Common Stock On July 23, 2021, the Company filed an amendment to its amended and restated certificate of incorporation, which effected a recapitalization of the Company’s then outstanding common stock to Class A common stock and authorized an additional new class of Class B common stock. The rights of the holders of Class A common stock and Class B common stock are substantially identical, except with respect to voting and conversion. Each share of Class A common stock is entitled to one vote are non-voting, except Restricted common stock The Company has outstanding shares of restricted common stock. Shares of unvested restricted common stock may not be sold or transferred by the holder. Vesting may be accelerated upon a change in control, as defined in the restricted stock agreement. If the holders cease to have a business relationship with the Company, the Company may repurchase any unvested shares of common stock held by these individuals at their original purchase price (which was a nominal amount).

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2021
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	9. Stock-Based Compensation 2017 Stock Option and Grant Plan The Company’s 2017 Stock Option and Grant Plan (the “2017 Plan”) provided for the Company to grant incentive stock options or nonqualified stock options and other equity awards to employees, directors and consultants of the Company. The 2017 Plan was administered by the board of directors or, at the discretion of the board of directors, by a committee of the board of directors. The exercise prices, vesting and other restrictions were determined at the discretion of the board of directors, or its committee if so delegated. Upon effectiveness of the Company’s 2021 Stock Option and Incentive Plan (the “2021 Plan”) in August 2021, the remaining shares available under the 2017 Plan ceased to be available for issuance and no future issuances will be made under the 2017 Plan. 2021 Equity Incentive Plan On July 23, 2021, the Company’s board of directors adopted and its stockholders approved the 2021 Plan, which became effective on J options, non-qualified stock the 2021 Plan and the 2017 Plan will be added back to the shares of Class A common stock available under the 2021 Plan. As of September 2021 Employee Stock Purchase Plan On July 23, 2021, the Company’s board of directors adopted and its stockholders approved the 2021 Employee Stock Purchase Plan (the “ESPP”), which became effective on July 28, 2021. A total of Option Grants During the nine months ended September 30, 2021, the Company granted options to its employees and directors with service-based vesting for the purchase of an aggregate of 3,360,647 shares of common stock with a total Stock-based compensation The Company recorded stock-based compensation expense related to common stock options and restricted common stock in the following expense categories of its statements of operations and comprehensive loss (in thousands): Three Months Ended September 30, Nine Months Ended 2021 2020 2021 2020 Research and development expenses $ 476 $ 12 $ 786 $ 641 General and administrative expenses 897 23 1,377 46 $ 1,373 $ 35 $ 2,163 $ 687 As of September 30, 2021, total unrecognized compensation cost related to common stock options and unvested restricted stock was $16.4 million, which is expected to be recognized over a weighted average period of 3.2 years.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	10. Commitments and Contingencies Revenue share The Company has revenue sharing agreements with Deerfield and the Company’s scientific founder to pay each of Deerfield and the scientific founder a low single digit percentage rate of net sales of certain commercial products. The payment obligation expires on the later of twelve years from the first commercial sale in a country or the expiration of the last-to-expire Indemnification agreements In the ordinary course of business, the Company may provide indemnification of varying scope and terms to vendors, lessors, contract research organizations, business partners and other parties with respect to certain matters including, but not limited to, losses arising out of breach of such agreements or from intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with members of its board of directors and its executive officers that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is, in many cases, unlimited. The Company has not incurred any material costs as a result of such indemnifications and is not currently aware of any indemnification claims.

Defined Contribution Plan

Defined Contribution Plan	9 Months Ended
	Sep. 30, 2021
Defined Contribution Plan [Abstract]
Defined Contribution Plan	11. Defined Contribution Plan The Company has a 401(k) defined contribution plan (the “401(k) Plan”) for its employees. Eligible employees may make pretax contributions to the 401(k) Plan up to statutory limits. There was no discretionary match made under the 401(k) Plan as of September 30, 2021 and December 31, 2020. In September 2021, the Company adopted a match program for employee contributions to the 401(k) Plan up to a maximum of six

Related Parties

Related Parties	9 Months Ended
	Sep. 30, 2021
Related Party Transactions [Abstract]
Related Parties	12. Related Parties The Company had issued certain promissory notes to Deerfield, an investor in the Company. In February 2021, the promissory notes and accrued interest were converted to Series A (see Note 6). The Company is obligated to pay low single digit percentage rates of net sales of certain commercial products to Deerfield and its scientific founder. As of September 30, 2021 and December 31, 2020, no products have been commercialized and no amounts have been paid or become due (see Note 10). In February 2017, the Company entered into a three-year consulting agreement with the scientific founder of the Company who is also a board member and a stockholder. The consulting agreement between the scientific founder and the Company continues at will. During the three months ended September 30, 2021 and 2020, the Company paid the scientific founder $0.2 million and $0.1 million, respectively. During the nine months ended September 30, 2021 and 2020, the Company paid $0.3 million and $0.1 million, respectively. As of September 30, 2021 and December 31, 2020, the Company had less than $0.1 million and no accounts payable, respectively, to the scientific founder. In June 2020, the Company loaned $0.3 million to the scientific founder of the Company who is also a board member and a stockholder of the Company related to the issuance of common stock (see Note 9) pu r d ore was was The promissory note was fully repaid and cancelled in July 2021.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Use of estimates	Use of estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting periods. Significant estimates and assumptions reflected in these financial statements include, but are not limited to, the valuation of common stock, the valuation of stock-based awards, preferred stock tranche rights and the accrual of research and development expenses. The Company bases its estimates on historical experience, known trends and other market-specific or other relevant factors that it believes to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates as there are changes in circumstances, facts and experience. Actual results may differ from those estimates or assumptions.
Unaudited interim financial information	Unaudited interim financial information The balance sheet at December 31, 2020 was derived from audited financial statements but does not include all disclosures required by GAAP. The accompanying unaudited financial statements as of September 30, 2021 and for the three and nine months ended September 30, 2021 and 2020 have been prepared by the Company pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim financial statements. Certain information and footnote disclosures normally included in the financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. These financial statements should be read in conjunction with the Company’s audited financial statements and the notes thereto for the year ended December 31, 2020 included in the Company’s Registration Statement on Form S-1, No. 333-257730
Concentrations of credit risk and of significant suppliers	Concentrations of credit risk and of significant suppliers Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash, cash equivalents and marketable securities. As of September 30, 2021 and December 31, 2020, the Company maintained cash, cash equivalents and marketable securities balances in excess of federally insured limits. The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. The Company is dependent on third-party vendors for the manufacturing of its product candidates. In particular, the Company relies, and expects to continue to rely, on a small number of vendors to manufacture materials and components required for the production of its product candidates. These programs could be adversely affected by a significant interruption in the manufacturing process.
Fair value measurements	Fair value measurements Certain assets and liabilities are carried at fair value under GAAP. 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 must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable: • Level 1—Quoted prices in active markets for identical assets or liabilities. • Level 2—Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data. • Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques. The Company’s cash equivalents and marketable securities are carried at fair value, determined according to the fair value hierarchy described above (see Note 4). The carrying values of the Company’s accounts payable and accrued expenses approximate their fair values due to the short-term nature of these liabilities .
Marketable securities	Marketable securities The Company’s marketable securities (non-equity available-for-sale . The Company evaluates its marketable securities with unrealized losses for other-than-temporary impairment. When assessing marketable securities for other-than-temporary declines in value, the Company considers 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, 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. If any adjustment to fair value reflects a decline in the value of the investment that the Company considers to be “other than temporary,” the Company reduces the investment to fair value through a charge recorded in the statements of operations. No such adjustments were necessary during the periods presented. The Company classifies its marketable securities with maturities beyond one year as short-term, based on their highly liquid nature and because such marketable securities are available for current operations.
Research and development costs	Research and development costs Research and development expenses consist of costs incurred in performing research and development activities, including salaries and bonuses, stock-based compensation, employee benefits, consulting costs, and external costs of vendors engaged to conduct research, preclinical and clinical development activities. Costs for research and development activities are expensed in the period in which they are incurred. Payments for such activities are based on the terms of the individual arrangements, which may differ from the pattern of costs incurred, and are reflected in the financial statements as prepaid expense or accrued research and development expense. Determining the prepaid and accrued balances at the end of any reporting period incorporates certain judgments and estimates by management that are based on information available to the Company including information provided by vendors regarding the progress to completion of specific tasks or costs incurred.
Stock-based compensation	Stock-based compensation The Company measures stock options with service-based vesting granted to employees, non-employees The Company classifies stock-based compensation expense in its statements of operations and comprehensive loss in the same manner in which the award recipient’s payroll costs are classified or in which the award recipient’s service payments are classified.
Net income (loss) per share	Net income (loss) per share Prior to the closing of the IPO, the Company followed the two-class method The two-class method The two-class method Subsequent to the closing of its IPO, basic net income (loss) per common share is computed by dividing the net income (loss) by the weighted average number of shares of common stock outstanding for the period. Diluted net income (loss) per common share is computed by dividing net income (loss) by the weighted average number of common shares outstanding for the period, including potential dilutive common shares assuming the dilutive effect of outstanding stock options and unvested restricted stock units. For periods in which the Company reported a net loss, diluted net loss per common share is the same as basic net loss per common share, since dilutive common shares are not assumed to have been issued if their affect is anti-dilutive. The Company has two classes of common stock outstanding: Class A common stock and Class B common stock. As more fully described in Note 8, the rights of the holders of Class A and Class B common stock are substantially identical, except with respect to voting and conversion. Each share of Class B common stock is convertible into one share of Class A common stock at the option of the holder at any time, subject to the ownership limitations provided for in the Company’s amended and restated certificate of incorporation. The Company allocates undistributed earnings attributable to common stock between the common stock classes on a one-to-one The Company excluded the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common stockholders for the three and nine months ended September 30, 2021 and 2020 because including them would have had an anti-dilutive effect: As of September 30, 2021 2020 Convertible preferred stock (as converted to common stock) — 16,711,823 Unvested restricted common stock 21,129 48,039 Options to purchase common stock 4,748,605 1,104,832 4,769,734 17,864,694
Recently issued accounting pronouncements	Recently issued accounting pronouncements The Company qualifies as an “emerging growth company” as defined in the JOBS Act and has elected not to “opt out” of the extended transition related to complying with new or revised accounting standards, which means that when a standard is issued or revised and it has different application dates for public and nonpublic companies, the Company will adopt the new or revised standard at the time nonpublic companies adopt the new or revised standard and will do so until such time that the Company either (i) irrevocably elects to “opt out” of such extended transition period or (ii) no longer qualifies as an emerging growth company. In February 2016, the FASB issued ASU No. 2016-02, 2016-02”), right-of-use 2016-02, 2018-10, 2018-11, No. 2020-05, one-year right-of-use In June 2016, the FASB issued ASU No. 2016-13, No. 2019-10,

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The Company excluded the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common stockholders for the three and nine months ended September 30, 2021 and 2020 because including them would have had an anti-dilutive effect: As of September 30, 2021 2020 Convertible preferred stock (as converted to common stock) — 16,711,823 Unvested restricted common stock 21,129 48,039 Options to purchase common stock 4,748,605 1,104,832 4,769,734 17,864,694

Marketable Securities (Tables)

Marketable Securities (Tables)	9 Months Ended
	Sep. 30, 2021
Marketable Securities [Abstract]
Summary of Marketable securities by Security	Marketable securities by security type consisted of the following (in thousands): September 30, 2021 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Commercial paper (due within one year) $ 46,269 $ — $ (17 ) $ 46,252 Corporate bonds (due within one year) 8,257 — (4 ) 8,253 Corporate bonds (due after one year through two years) 2,040 — (2 ) 2,038 $ 56,566 $ — $ (23 ) $ 56,543

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis	The following tables present the Company’s fair value hierarchy for its assets and liabilities, which are measured at fair value on a recurring basis (in thousands): Fair Value Measurements at September 30, 2021 Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 239,383 $ — $ — $ 239,383 Commercial paper — 5,499 — 5,499 Marketable securities: Corporate bonds — 10,291 — 10,291 Commercial paper — 46,252 — 46,252 $ 239,383 $ 62,042 $ — $ 301,425 Fair Value Measurements at December 31, Level 1 Level 2 Level 3 Total Liabilities: Preferred stock tranche rights $ — $ — $ 1,957 $ 1,957
Schedule of Roll Forward of the Aggregate Fair Value of the Preferred Stock Tranche Rights	The following table provides a roll-forward of the aggregate fair values of the Company’s preferred stock tranche rights, for which fair value was determined by Level 3 inputs (in thousands): Preferred Stock Fair value at December 31, 2020 $ 1,957 Change in fair value 635 Settlement of preferred stock tranche rights (2,592 ) Fair value at September 30, 2021 $ —

Accrued Expenses (Tables)

Accrued Expenses (Tables)	9 Months Ended
	Sep. 30, 2021
Accrued Liabilities, Current [Abstract]
Schedule of Accrued Expenses	Accrued expenses consisted of the following (in thousands): September 30, 2021 December 31, 2020 Accrued employee compensation and benefits $ 1,679 $ 636 Accrued external research and development expenses 880 405 Accrued professional fees 1,751 103 Other — 27 $ 4,310 $ 1,171

Convertible Preferred Stock (Ta

Convertible Preferred Stock (Tables)	9 Months Ended
	Sep. 30, 2021
Stockholders' Equity Note [Abstract]
Schedule of Redeemable Convertible Preferred Stock	Preferred Stock consisted of the following as of December 31, 2020: Preferred Preferred Stock Carrying Value Liquidation Common Stock (in thousands) (in thousands) Series A Preferred Stock 112,431,508 89,945,206 $ 35,354 $ 40,000 16,711,823 112,431,508 89,945,206 $ 35,354 $ 40,000 16,711,823

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2021
Share-based Payment Arrangement [Abstract]
Summary of Stock-Based Compensation Expenses	The Company recorded stock-based compensation expense related to common stock options and restricted common stock in the following expense categories of its statements of operations and comprehensive loss (in thousands): Three Months Ended September 30, Nine Months Ended 2021 2020 2021 2020 Research and development expenses $ 476 $ 12 $ 786 $ 641 General and administrative expenses 897 23 1,377 46 $ 1,373 $ 35 $ 2,163 $ 687

Nature of Business and Basis _2

Nature of Business and Basis of Presentation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Aug. 02, 2021	Jul. 23, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Reverse stock split		one-for-5.38213
Net proceeds from initial public offering	$ 174,300
Net loss			$ (12,426)	$ (9,838)	$ (6,785)	$ (4,778)	$ (8,557)	$ 5,359	$ (29,049)	$ (7,976)	$ (14,600)
Accumulated deficit			$ (60,934)						$ (60,934)		$ (31,885)
Common Class A [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Common stock, voting rights		one vote
Common Class A [Member] | IPO [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Stock issued during period shares new shares	10,612,500
Shares issued price per share	$ 17
Common Class A [Member] | IPO [Member] | Over-Allotment Option [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Stock issued during period shares new shares	1,462,500
Common Class B [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Common stock, terms of conversion		Each share of Class B common stock may be converted at any time into one share of Class A common stock at the option of its holder, subject to the ownership limitations provided for in the Company’s amended and restated certificate of incorporation.
Common Class B [Member] | IPO [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Stock issued during period shares new shares	600,000
Shares issued price per share	$ 17

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share (Detail) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	4,769,734	17,864,694	4,769,734	17,864,694
Convertible preferred stock (as converted to common stock) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	0	16,711,823	0	16,711,823
Unvested restricted common stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	21,129	48,039	21,129	48,039
Options to purchase common stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	4,748,605	1,104,832	4,748,605	1,104,832

Marketable Securities - Summary

Marketable Securities - Summary of Marketable securities by Security (Detail) $ in Thousands	Sep. 30, 2021USD ($)
Marketable Securities [Line Items]
Amortized Cost	$ 56,566
Gross Unrealized Losses	(23)
Fair Value	56,543
Corporate bonds | Due from one to two years
Marketable Securities [Line Items]
Amortized Cost	2,040
Gross Unrealized Losses	(2)
Fair Value	2,038
Corporate bonds | Due within one year
Marketable Securities [Line Items]
Amortized Cost	8,257
Gross Unrealized Losses	(4)
Fair Value	8,253
Commercial paper
Marketable Securities [Line Items]
Amortized Cost	46,269
Gross Unrealized Losses	(17)
Fair Value	$ 46,252

Marketable Securities - Additio

Marketable Securities - Additional Information (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Marketable Securities [Abstract]
Marketable securities	$ 56,543	$ 0

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Assets:
Total assets	$ 301,425
Money Market Funds [Member]
Assets:
Cash equivalents	239,383
Commercial Paper [Member]
Assets:
Cash equivalents	5,499
Marketable securities	46,252
Corporate Bond Securities [Member]
Assets:
Marketable securities	10,291
Fair value, inputs, level 1 [Member]
Assets:
Total assets	239,383
Fair value, inputs, level 1 [Member] | Money Market Funds [Member]
Assets:
Cash equivalents	239,383
Fair value, inputs, level 2 [Member]
Assets:
Total assets	62,042
Fair value, inputs, level 2 [Member] | Commercial Paper [Member]
Assets:
Cash equivalents	5,499
Marketable securities	46,252
Fair value, inputs, level 2 [Member] | Corporate Bond Securities [Member]
Assets:
Marketable securities	$ 10,291
Preferred stock tranche rights [Member]
Liabilities:
Preferred stock tranche rights		$ 1,957
Preferred stock tranche rights [Member] | Fair value, inputs, level 3 [Member]
Liabilities:
Preferred stock tranche rights		$ 1,957

Fair Value Measurements - Sch_2

Fair Value Measurements - Schedule of Roll Forward of the Aggregate Fair Value of the Preferred Stock Tranche Rights (Detail) - Preferred stock tranche rights [Member] - Fair value, inputs, level 3 [Member] $ in Thousands	9 Months Ended
	Sep. 30, 2021USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value at December 31, 2020	$ 1,957
Change in fair value	635
Settlement of preferred stock tranche rights	(2,592)
Fair value at September 30, 2021	$ 0

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021USD ($)yr	Sep. 30, 2020USD ($)	Sep. 30, 2021USD ($)yr	Sep. 30, 2020USD ($)	Dec. 31, 2020$ / shares
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value transfers in or out of Level 3 | $	$ 0	$ 0	$ 0	$ 0
Series A convertible preferred stock [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Redeemable convertible preferred stock fair value per share | $ / shares					$ 0.53
Maximum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Probability of achieving milestones	100.00%		100.00%
Minimum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Probability of achieving milestones	90.00%		90.00%
Measurement input, expected dividend rate [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible preferred stock, measurement input	0		0
Measurement input, expected term [Member] | Maximum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible preferred stock, measurement input	1.6		1.6
Measurement input, expected term [Member] | Minimum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible preferred stock, measurement input	0.2		0.2

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Accrued Liabilities, Current [Abstract]
Accrued employee compensation and benefits	$ 1,679	$ 636
Accrued external research and development expenses	880	405
Accrued professional fees	1,751	103
Other	0	27
Total Accrued expenses	$ 4,310	$ 1,171

Notes Payable to Related Party

Notes Payable to Related Party - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended	9 Months Ended
	Feb. 28, 2021	Feb. 28, 2017	Mar. 31, 2021	Sep. 30, 2021
Related Party Transaction [Line Items]
Loss on extinguishment of debt			$ (580)	$ (580)
Convertible preferred stock [Member]
Related Party Transaction [Line Items]
Conversion of note payable and accrued interest to Series A convertible preferred stock , Shares			5,025,604
Deerfield Healthcare Innovations Fund L.P. And Deerfield Private Design Fund IV, L.P [Member] | Promissory Note [Member]
Related Party Transaction [Line Items]
Debt instrument face amount		$ 2,000
Debt instrument interest rate percentage		2.81%
Loss on extinguishment of debt	$ (600)
Deerfield Healthcare Innovations Fund L.P. And Deerfield Private Design Fund IV, L.P [Member] | Promissory Note [Member] | Maximum [Member]
Related Party Transaction [Line Items]
Debt instrument term		5 years
Deerfield Healthcare Innovations Fund L.P. And Deerfield Private Design Fund IV, L.P [Member] | Promissory Note [Member] | Convertible preferred stock [Member]
Related Party Transaction [Line Items]
Conversion of note payable and accrued interest to Series A convertible preferred stock , Shares	5,025,604

Convertible Preferred Stock - S

Convertible Preferred Stock - Summary of Redeemable Convertible Preferred Stock (Detail) $ in Thousands	Dec. 31, 2020USD ($)shares
Temporary Equity [Line Items]
Preferred Stock Authorized	112,431,508
Preferred Stock Issued	89,945,206
Preferred Stock Outstanding	89,945,206
Carrying Value | $	$ 35,354
Liquidation Preference | $	$ 40,000
Common Stock Issuable Upon Conversion	16,711,823
Series A Preferred Stock [Member]
Temporary Equity [Line Items]
Preferred Stock Authorized	112,431,508
Preferred Stock Issued	89,945,206
Preferred Stock Outstanding	89,945,206
Carrying Value | $	$ 35,354
Liquidation Preference | $	$ 40,000
Common Stock Issuable Upon Conversion	16,711,823

Convertible Preferred Stock - A

Convertible Preferred Stock - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	9 Months Ended
	Apr. 30, 2021	Sep. 30, 2021	Sep. 30, 2020
Class of Stock [Line Items]
Gross Proceeds from issuance of convertible preferred stock		$ 144,652	$ 22,500
Series B convertible preferred stock [Member]
Class of Stock [Line Items]
Issuance of convertible preferred stock , Shares	65,223,679
Issuance price per share	$ 2.0698
Gross Proceeds from issuance of convertible preferred stock	$ 135,000
Number of tranche rights granted temporary equity		0

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock-Based Compensation Expenses (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation	$ 1,373	$ 35	$ 2,163	$ 687
Research and Development Expenses [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation	476	12	786	641
General and Administrative Expenses [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation	$ 897	$ 23	$ 1,377	$ 46

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ in Millions	Jul. 28, 2021	Sep. 30, 2021
Unrecognized compensation cost related to common stock options and unvested restricted stock		$ 16.4
Share based payment weighted average period		3 years 2 months 12 days
2021 Equity Incentive Plan [Member]
Shares available for future issurance		5,441,507
2021 Equity Incentive Plan [Member] | Common Class A [Member]
Common stock reserved for issuance	5,866,004
2021 Employee Stock Purchase Plan [Member]
Service-based vesting options granted		3,360,647
Share based payment award options granted, weighted average grant date fair value		$ 18
2021 Employee Stock Purchase Plan [Member] | Common Class A [Member]
Common stock reserved for issuance	473,064
Maximum [Member] | 2021 Equity Incentive Plan [Member] | Class A and Class B Common Stock [Member]
Share based compensation arrangement by share based payment award cumulative annual increase percentage	5.00%
Maximum [Member] | 2021 Employee Stock Purchase Plan [Member] | Common Class A [Member]
Share based compensation arrangement by share based payment award annual increase amount	473,064
Maximum [Member] | 2021 Employee Stock Purchase Plan [Member] | Class A and Class B Common Stock [Member]
Share based compensation arrangement by share based payment award annual increase percentage	1.00%

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Accrued liability	$ 0	$ 0

Defined Contribution Plan - Add

Defined Contribution Plan - Additional Information (Detail) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2022	Dec. 31, 2020
Defined contribution plan, employer discretionary contribution amount	$ 0		$ 0
Forecast [Member]
Defined contribution plan employer matching contribution percent of match		6.00%

Related Parties - Additional In

Related Parties - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Jun. 30, 2020
Consulting Agreement [Member]
Related party amounts paid	$ 0.2	$ 0.1	$ 0.3	$ 0.1
Accounts payable, related parties					$ 0
Consulting Agreement [Member] | Maximum [Member]
Accounts payable, related parties	$ 0.1		$ 0.1
Scientific Founder [Member]
Notes receivable related parties						$ 0.3
Loan bears interest rate						2.86%
Promissory note maturity date description			The promissory note provided that the maturity date of the promissory note would occur on the earliest to occur of (i) June 11, 2024, (ii) 60 calendar days following the date of termination of services of the stockholder, and (iii) immediately prior to an initial filing of a registration statement by the Company.