Foghorn Therapeutics (FHTX) 10-Q 2 Nov 23 2023 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2023	Oct. 31, 2023
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2023
Document Transition Report	false
Entity File Number	001-39634
Entity Registrant Name	Foghorn Therapeutics Inc.
Entity Incorporation, State	DE
Entity Tax Identification Number	47-5271393
Entity Address, Street Name	500 Technology Square, Ste 700
Entity Address, City	Cambridge
Entity Address, State	MA
Entity Address, Postal Zip Code	02139
City Area Code	617
Local Phone Number	586-3100
Title of each class	Common Stock, $0.0001 par value per share
Trading Symbol(s)	FHTX
Name of each exchange on which registered	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
Entity Common Stock, Shares Outstanding		42,217,126
Amendment Flag	false
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q3
Entity Central Index Key	0001822462
Current Fiscal Year End Date	--12-31

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 70,306	$ 52,214
Marketable securities	189,582	293,584
Prepaid expenses and other current assets	5,554	5,601
Total current assets	265,442	351,399
Property and equipment, net	13,793	15,311
Restricted cash	1,708	1,708
Other assets	1,129	2,379
Operating lease right-of-use assets	31,351	34,086
Total assets	313,423	404,883
Current liabilities:
Accounts payable	6,496	5,414
Accrued expenses and other current liabilities	8,799	11,001
Operating lease liabilities	8,372	5,970
Deferred revenue	28,345	32,820
Total current liabilities	52,012	55,205
Operating lease liabilities, net of current portion	38,710	45,537
Deferred revenue, net of current portion	280,089	304,000
Other liabilities	0	29
Total liabilities	370,811	404,771
Commitments and contingencies (Note 10)
Stockholders’ equity (deficit):
Preferred stock, $0.0001 par value; 25,000,000 shares authorized at September 30, 2023 and December 31, 2022; no shares issued and outstanding at September 30, 2023 and December 31, 2022	0	0
Common stock, $0.0001 par value; 175,000,000 shares authorized at September 30, 2023 and December 31, 2022; 42,217,126 shares issued and outstanding at September 30, 2023 and 41,803,436 shares issued and outstanding at December 31, 2022	4	4
Additional paid-in capital	391,959	377,232
Accumulated other comprehensive loss	(1,893)	(3,986)
Accumulated deficit	(447,458)	(373,138)
Total stockholders’ equity (deficit)	(57,388)	112
Total liabilities and stockholders’ equity (deficit)	$ 313,423	$ 404,883

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	25,000,000	25,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	175,000,000	175,000,000
Common stock, shares issued (in shares)	42,217,126	41,803,436
Common stock, shares outstanding (in shares)	42,217,126	41,803,436

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Income Statement [Abstract]
Collaboration revenue	$ 17,478	$ 6,634	$ 28,386	$ 15,044
Operating expenses:
Research and development	26,251	26,928	85,484	77,410
General and administrative	8,308	7,965	25,350	22,885
Total operating expenses	34,559	34,893	110,834	100,295
Loss from operations	(17,081)	(28,259)	(82,448)	(85,251)
Other income (expense):
Interest income	2,753	1,839	8,215	3,299
Other income, net	721	651	2,153	1,956
Total other income, net	3,474	2,490	10,368	5,255
Loss before income taxes	(13,607)	(25,769)	(72,080)	(79,996)
Provision for income taxes	(738)	0	(2,240)	0
Net loss	$ (14,345)	$ (25,769)	$ (74,320)	$ (79,996)
Net loss per share attributable to common stockholders—basic (in dollars per share)	$ (0.34)	$ (0.62)	$ (1.77)	$ (1.93)
Net loss per share attributable to common stockholders—diluted (in dollars per share)	$ (0.34)	$ (0.62)	$ (1.77)	$ (1.93)
Weighted average common shares outstanding—basic (in shares)	42,025,938	41,672,621	41,888,314	41,520,498
Weighted average common shares outstanding—diluted (in shares)	42,025,938	41,672,621	41,888,314	41,520,498
Comprehensive loss:
Net loss	$ (14,345)	$ (25,769)	$ (74,320)	$ (79,996)
Other comprehensive loss:
Unrealized gains (losses) on marketable securities	826	(1,675)	2,093	(4,854)
Total other comprehensive gain (loss)	826	(1,675)	2,093	(4,854)
Total comprehensive loss	$ (13,519)	$ (27,444)	$ (72,227)	$ (84,850)

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders’ Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Gain (Loss)	Accumulated Deficit
Beginning balance at Dec. 31, 2021	$ 96,871	$ 4	$ 361,133	$ (10)	$ (264,256)
Beginning balance (in shares) at Dec. 31, 2021		41,299,720
Increase (Decrease) in Stockholders' Equity
Issuance of common stock upon exercise of stock options and employee stock purchase plan	384		384
Issuance of common stock upon exercise of stock options and employee stock purchase plan (in shares)		129,895
Stock-based compensation expense	3,244		3,244
Unrealized gains (losses) on marketable securities	(1,184)			(1,184)
Net loss	(26,914)				(26,914)
Ending balance at Mar. 31, 2022	72,401	$ 4	364,761	(1,194)	(291,170)
Ending balance (in shares) at Mar. 31, 2022		41,429,615
Beginning balance at Dec. 31, 2021	96,871	$ 4	361,133	(10)	(264,256)
Beginning balance (in shares) at Dec. 31, 2021		41,299,720
Increase (Decrease) in Stockholders' Equity
Net loss	(79,996)
Ending balance at Sep. 30, 2022	24,323	$ 4	373,435	(4,864)	(344,252)
Ending balance (in shares) at Sep. 30, 2022		41,799,368
Beginning balance at Mar. 31, 2022	72,401	$ 4	364,761	(1,194)	(291,170)
Beginning balance (in shares) at Mar. 31, 2022		41,429,615
Increase (Decrease) in Stockholders' Equity
Issuance of common stock upon exercise of stock options and employee stock purchase plan	1,030		1,030
Issuance of common stock upon exercise of stock options and employee stock purchase plan (in shares)		198,297
Stock-based compensation expense	3,509		3,509
Unrealized gains (losses) on marketable securities	(1,995)			(1,995)
Net loss	(27,313)				(27,313)
Ending balance at Jun. 30, 2022	47,632	$ 4	369,300	(3,189)	(318,483)
Ending balance (in shares) at Jun. 30, 2022		41,627,912
Increase (Decrease) in Stockholders' Equity
Issuance of common stock upon exercise of stock options and employee stock purchase plan	334		334
Issuance of common stock upon exercise of stock options and employee stock purchase plan (in shares)		171,456
Stock-based compensation expense	3,801		3,801
Unrealized gains (losses) on marketable securities	(1,675)			(1,675)
Net loss	(25,769)				(25,769)
Ending balance at Sep. 30, 2022	24,323	$ 4	373,435	(4,864)	(344,252)
Ending balance (in shares) at Sep. 30, 2022		41,799,368
Beginning balance at Dec. 31, 2022	$ 112	$ 4	377,232	(3,986)	(373,138)
Beginning balance (in shares) at Dec. 31, 2022	41,803,436	41,803,436
Increase (Decrease) in Stockholders' Equity
Issuance of common stock upon exercise of stock options and employee stock purchase plan	$ 102		102
Issuance of common stock upon exercise of stock options and employee stock purchase plan (in shares)		21,322
Stock-based compensation expense	4,572		4,572
Unrealized gains (losses) on marketable securities	1,116			1,116
Net loss	(30,488)				(30,488)
Ending balance at Mar. 31, 2023	(24,586)	$ 4	381,906	(2,870)	(403,626)
Ending balance (in shares) at Mar. 31, 2023		41,824,758
Beginning balance at Dec. 31, 2022	$ 112	$ 4	377,232	(3,986)	(373,138)
Beginning balance (in shares) at Dec. 31, 2022	41,803,436	41,803,436
Increase (Decrease) in Stockholders' Equity
Net loss	$ (74,320)
Ending balance at Sep. 30, 2023	$ (57,388)	$ 4	391,959	(1,893)	(447,458)
Ending balance (in shares) at Sep. 30, 2023	42,217,126	42,217,126
Beginning balance at Mar. 31, 2023	$ (24,586)	$ 4	381,906	(2,870)	(403,626)
Beginning balance (in shares) at Mar. 31, 2023		41,824,758
Increase (Decrease) in Stockholders' Equity
Issuance of common stock upon exercise of stock options and employee stock purchase plan	102		102
Issuance of common stock upon exercise of stock options and employee stock purchase plan (in shares)		27,680
Stock-based compensation expense	4,470		4,470
Unrealized gains (losses) on marketable securities	151			151
Net loss	(29,487)				(29,487)
Ending balance at Jun. 30, 2023	(49,350)	$ 4	386,478	(2,719)	(433,113)
Ending balance (in shares) at Jun. 30, 2023		41,852,438
Increase (Decrease) in Stockholders' Equity
Issuance of common stock upon exercise of stock options and employee stock purchase plan	1,387		1,387
Issuance of common stock upon exercise of stock options and employee stock purchase plan (in shares)		364,688
Stock-based compensation expense	4,094		4,094
Unrealized gains (losses) on marketable securities	826			826
Net loss	(14,345)				(14,345)
Ending balance at Sep. 30, 2023	$ (57,388)	$ 4	$ 391,959	$ (1,893)	$ (447,458)
Ending balance (in shares) at Sep. 30, 2023	42,217,126	42,217,126

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Cash flows from operating activities:
Net loss	$ (14,345)	$ (25,769)	$ (74,320)	$ (79,996)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Stock-based compensation expense	4,094	3,802	13,135	10,555
Depreciation and amortization expense	900	900	2,599	2,473
Loss on disposal of property and equipment			3	0
Noncash lease expense			3,815	2,510
Accretion of discount on marketable securities			(2,156)	(721)
Changes in operating assets and liabilities:
Prepaid expenses and other current assets			1,297	1,068
Collaboration receivable			0	300,000
Accounts payable			1,082	1,457
Accrued expenses and other liabilities			(2,129)	547
Operating lease liabilities			(5,505)	(5,313)
Deferred revenue			(28,386)	(10,044)
Net cash provided by (used in) operating activities			(90,565)	222,536
Cash flows from investing activities:
Purchases of property and equipment			(1,187)	(941)
Proceeds from sale of property and equipment			1	0
Purchases of marketable securities			(67,061)	(365,006)
Proceeds from maturities of marketable securities			175,312	128,132
Net cash provided by (used in) investing activities			107,065	(237,815)
Cash flows from financing activities:
Proceeds from issuance of common stock upon exercise of stock options and employee stock purchase plan			1,592	1,747
Net cash provided by financing activities			1,592	1,747
Net increase (decrease) in cash, cash equivalents and restricted cash			18,092	(13,532)
Cash, cash equivalents and restricted cash at beginning of period			53,922	102,869
Cash, cash equivalents and restricted cash at end of period	72,014	89,337	72,014	89,337
Supplemental disclosure of noncash investing and financing information:
Cash paid for taxes			2,686	0
Purchases of property and equipment included in accounts payable and accrued expenses			58	204
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents	70,306	87,604	70,306	87,604
Restricted cash (current and non-current)	1,708	1,733	1,708	1,733
Total cash, cash equivalents and restricted cash shown in the statement of cash flows	$ 72,014	$ 89,337	$ 72,014	$ 89,337

Nature of Business, Going Conce

Nature of Business, Going Concern and Basis of Presentation	9 Months Ended
	Sep. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Business, Going Concern and Basis of Presentation	Nature of Business, Going Concern and Basis of Presentation Foghorn Therapeutics Inc. (the “Company”) is a clinical-stage biopharmaceutical company discovering and developing a new class of medicines targeting genetically determined dependencies within the chromatin regulatory system. The Company uses its proprietary Gene Traffic Control platform to identify, validate and potentially drug targets within the system. The Company was founded in October 2015 as a Delaware corporation. The Company is headquartered in Cambridge, Massachusetts. The Company is subject to risks similar to those of other early-stage companies in the biopharmaceutical industry, including dependence on key individuals, the need to develop commercially viable products, competition from other companies, many of whom are larger and better capitalized, and the need to obtain adequate additional financing to fund the development of its products. There can be no assurance that the Company’s research and development will be successfully completed, that adequate protection for the Company’s intellectual property will be maintained, that any products developed will obtain required regulatory approval or that any approved products will be commercially viable. Even if the Company’s development efforts are successful, it is uncertain when, if ever, the Company will generate significant revenue from the sale of its products. Going concern The accompanying condensed consolidated financial statements have been prepared on the basis of continuity of operations, realization of assets and the satisfaction of liabilities and commitments in the ordinary course of business. Since inception, the Company has funded its operations primarily with proceeds from sales of preferred stock, debt financing, an upfront payment from a collaboration agreement, a public offering and a stock purchase agreement all prior to 2022. In January 2022, the Company received an upfront payment of $300.0 million pursuant to a collaboration agreement (the “Lilly Collaboration Agreement”) completed with Eli Lilly and Company (“Lilly”) (see Note 8). In the third quarter of 2022, the Company achieved a research milestone related to a collaboration agreement (the “Merck Collaboration Agreement”) and received a $5.0 million milestone payment from Merck Sharp & Dohme Corp. (“Merck”). The Company has incurred recurring losses, including net losses of $74.3 million and $80.0 million for the nine months ended September 30, 2023 and 2022, respectively. As of September 30, 2023, the Company had an accumulated deficit of $447.5 million. The Company expects to continue to generate operating losses in the foreseeable future. As of the issuance date of these interim condensed consolidated financial statements the Company expects that its cash, cash equivalents and marketable securities will be sufficient to fund its operating expenses and capital expenditure requirements for at least 12 months. The Company will need to obtain additional funding through public or private equity offerings, debt financings, collaborations, strategic alliances and/or licensing arrangements to continue to fund its operations. 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 collaborative or strategic alliances or licensing arrangements. 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 could be forced to delay, reduce or eliminate some or all of its research and development programs, pipeline expansion or commercialization efforts, which could adversely affect its business prospects. Although management will continue to pursue these plans, there is no assurance that the Company will be successful in obtaining sufficient funding in the future on terms acceptable to the Company to fund continuing operations when needed or at all. Basis of presentation The Company’s condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”) and pursuant to the rules and regulations of the United States Securities and Exchange Commission for interim financial statements. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. The accompanying condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary. All intercompany accounts and transactions have been eliminated in consolidation. 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”).

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies The accounting policies of the Company are set forth in Note 2 to the consolidated financial statements contained in the Company’s 2022 Annual Report on Form 10-K. The Company includes herein certain updates to those policies. Marketable Securities The Company’s marketable securities are classified as available-for-sale and are carried at fair value with the unrealized gains and losses reported as a component of accumulated other comprehensive loss in stockholders’ equity. 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. The Company reviews marketable securities whenever the fair value of an investment is less than the amortized cost and evidence indicates that an investment’s carrying value is not recoverable. For available-for-sale debt securities, the credit allowance is limited to the amount that fair value is less than amortized cost. Unrealized losses are evaluated for impairment under ASC 326, Financial Instruments - Credit Losses , to determine if the impairment is credit-related or noncredit-related. Credit-related impairment is recognized as an allowance on the condensed consolidated balance sheets with a corresponding adjustment to earnings, and noncredit-related impairment is recognized in other comprehensive loss. Evidence considered in this assessment includes reasons for the impairment, compliance with our investment policy, the severity of the impairment, collectability of the security, and any adverse conditions specifically related to the security, an industry, or geographic area. Unrealized gains and losses are included as a component of accumulated other comprehensive loss in the condensed consolidated balance sheets and condensed consolidated statements of stockholders’ equity and a component of total comprehensive loss. Realized gains and losses are included as a component of other income (expense), net based on the specific identification method. Recently issued accounting pronouncements From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies that the Company adopts as of the specified effective date. The Company qualifies as an “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012 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 can adopt the new or revised standard at the time nonpublic companies adopt the new or revised standard and can 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 June 2016, the FASB issued ASU No. 2016-13, Financial Instruments – Credit Losses (Topic 326) . The new standard adjusts the accounting for assets held at amortized costs basis by eliminating the probable initial recognition threshold and requires an entity to reflect its current estimate of all expected credit losses as an allowance for credit losses. For nonpublic entities and emerging growth companies that choose to take advantage of the extended transition period, the guidance was initially effective for annual reporting periods beginning after December 15, 2020. However, in November 2019, the FASB issued ASU No. 2019-10, which deferred the effective date for nonpublic entities to annual reporting periods beginning after December 15, 2022, including interim periods within those fiscal years. The Company adopted this as of January 1, 2023 and the adoption had no material impact to the Company’s consolidated financial position, results of operation, or cash flows.

Marketable Securities and Fair

Marketable Securities and Fair Value Measurements	9 Months Ended
	Sep. 30, 2023
Fair Value Disclosures [Abstract]
Marketable Securities and Fair Value Measurements	Marketable Securities and Fair Value Measurements As of September 30, 2023, available for sale marketable securities by security type consisted of (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value U.S. treasury notes (due within one year) $ 2,997 $ — $ (32) $ 2,965 U.S. government agencies (due within one year) 11,813 — (73) 11,740 Commercial paper (due within one year) 15,815 — (10) 15,805 Corporate notes and bonds (due within one year) 143,589 1 (1,475) 142,115 Corporate notes and bonds (due after one year through two 17,261 — (304) 16,957 Total $ 191,475 $ 1 $ (1,894) $ 189,582 As of December 31, 2022, available for sale marketable securities by security type consisted of (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value U.S. treasury notes (due within one year) $ 7,987 $ — $ (115) $ 7,872 Commercial paper (due within one year) 56,697 2 (301) 56,398 Corporate notes and bonds (due within one year) 139,764 — (1,342) 138,422 Corporate notes and bonds (due after one year through three 93,122 4 (2,234) 90,892 Total $ 297,570 $ 6 $ (3,992) $ 293,584 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, 2023 Using: Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 69,311 $ — $ — $ 69,311 Commercial paper — 995 — 995 Marketable securities: U.S. treasury notes — 2,965 — 2,965 U.S. government agencies — 11,740 — 11,740 Commercial paper — 15,805 — 15,805 Corporate notes and bonds — 159,072 — 159,072 Total $ 69,311 $ 190,577 $ — $ 259,888 Fair Value Measurements at December 31, 2022 Using: Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 28,077 $ — $ — $ 28,077 U.S. treasury notes — 1,998 — 1,998 Commercial paper — 22,139 — 22,139 Marketable securities: U.S. treasury notes — 7,872 — 7,872 Commercial paper — 56,398 — 56,398 Corporate notes and bonds — 229,314 — 229,314 Total $ 28,077 $ 317,721 $ — $ 345,798 For the three and nine months ended September 30, 2023 and 2022, there were no transfers between Level 1, Level 2 and Level 3.

Property and Equipment, Net

Property and Equipment, Net	9 Months Ended
	Sep. 30, 2023
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	Property and Equipment, Net Property and equipment, net consisted of the following (in thousands): September 30, 2023 December 31, 2022 Laboratory equipment $ 6,788 $ 5,884 Furniture and fixtures 815 815 Computer equipment and software 115 100 Leasehold improvements 17,239 17,123 24,957 23,922 Less: Accumulated depreciation and amortization (11,164) (8,611) $ 13,793 $ 15,311 Depreciation and amortization expense was $0.9 million for both the three months ended September 30, 2023 and 2022 and $2.6 million and $2.5 million for the nine months ended September 30, 2023 and 2022, respectively.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	9 Months Ended
	Sep. 30, 2023
Payables and Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	Accrued Expenses and Other Current Liabilities Accrued expenses consisted of the following (in thousands): September 30, 2023 December 31, 2022 Accrued external research and development expenses $ 2,967 $ 5,262 Accrued employee compensation and benefits 4,692 4,743 Accrued professional fees 839 678 Other 301 318 $ 8,799 $ 11,001

Common Stock and Net Loss Per S

Common Stock and Net Loss Per Share	9 Months Ended
	Sep. 30, 2023
Equity [Abstract]
Common Stock and Net Loss Per Share	Common Stock and Net Loss Per Share Common Stock Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders. Common stockholders are not entitled to receive dividends, unless declared by the board of directors. Net Loss Per Share The following common stock equivalents presented based on amounts outstanding at each period end have been excluded from the calculation of diluted net loss per share because including them would have had an anti-dilutive impact: September 30, 2023 2022 Stock options to purchase common stock 9,532,730 7,860,248 Warrants to purchase common stock 18,445 18,445 9,551,175 7,878,693

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2023
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation 2020 Equity Incentive Plan The Company’s 2020 Equity Incentive Plan (the “2020 Plan”) provides for the grant of incentive stock options, non-qualified options, stock appreciation rights, restricted stock awards, restricted stock units and other stock-based awards. The number of shares initially reserved for issuance under the 2020 Plan was (i) 2,200,000 shares (the “share pool”), plus (ii) the number of shares of common stock available for issuance under the Company’s 2016 Stock Incentive Plan (the “2016 Plan”) as of the effective date of the 2020 Plan, plus the number of shares of common stock underlying awards under the 2016 Plan that on or after the date of adoption expire or become unexercisable without delivery of shares, are forfeited to, or repurchased for cash, are settled in cash, or otherwise become available again for grant under the 2016 Plan, in each case, in accordance with its terms (up to an aggregate of 5,078,295 shares). As of September 30, 2023, 1,121,971 shares remained available for future grant under the 2020 Plan. The share pool will automatically increase on January 1 of each year from 2021 to 2030 by the lesser of (i) four percent of the number of shares of our common stock outstanding as of the close of business on the immediately preceding December 31 and (ii) the number of shares determined by the board of directors on or prior to such date for such year. The number of shares reserved for issuance under the 2020 Plan was increased by 1,672,137 shares effective January 1, 2023. The 2020 Plan is 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 are determined at the discretion of the board of directors, or its committee if so delegated. Stock options granted with service-based vesting conditions generally vest over four years and expire after ten years. The exercise price for stock options granted is not less than the fair value of common stock on the date of grant. The Company bases fair value of common stock on the quoted market price. 2020 Employee Stock Purchase Plan On October 21, 2020, the Company’s board of directors adopted and its stockholders approved the 2020 Employee Stock Purchase Plan (the “ESPP”), which became effective on October 21, 2020. The aggregate number of shares of common stock available for purchase pursuant to the exercise of options under the ESPP is 360,000 shares, plus an automatic annual increase, as of January 1 of each year from 2021 to 2030, equal to the lesser of one percent of the number of shares of common stock outstanding as of the close of business on the immediately preceding December 31 and (ii) the number of shares determined by the board of directors on or prior to such date for such year (up to a maximum of 3,220,520 shares). The number of shares reserved for issuance under the ESPP was increased by 418,034 shares to 1,184,497 shares effective January 1, 2023. Eligible employees may authorize payroll deductions of up to 15% of their eligible compensation during an offering period. The purchase of shares is done at a 15% discount on the lesser of (i) the Fair Market Value of a share of Stock on the first day of the offering period and (ii) the Fair Market Value of a share of Stock on the last day of the offering period. The Company currently holds two offering periods, September 1 and March 1, respectively. The first offering period commenced under the ESPP on September 1, 2021. The Company recognized a de minimis amount of expense related to the ESPP for the three months ended September 30, 2023 and 2022, respectively. The Company recognized $0.1 million and a de minimis amount of expense related to the ESPP for the nine months ended September 30, 2023 and 2022, respectively. Stock-Based Compensation Stock-based compensation expense was classified in the condensed consolidated statements of operations and comprehensive loss as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Research and development expenses $ 1,776 $ 1,689 $ 5,800 $ 4,784 General and administrative expenses 2,318 2,113 7,335 5,771 $ 4,094 $ 3,802 $ 13,135 $ 10,555 As of September 30, 2023, total unrecognized compensation cost related to unvested options was $32.8 million, which is expected to be recognized over a weighted average period of 2.4 years.

Collaboration Agreements

Collaboration Agreements	9 Months Ended
	Sep. 30, 2023
Collaboration Agreement [Abstract]
Collaboration Agreements	Collaboration Agreements Lilly Collaboration Agreement and Stock Purchase Agreement In December 2021, the Company entered into the Lilly Collaboration Agreement with Lilly to create novel oncology medicines by applying Foghorn’s proprietary Gene Traffic Control platform. The collaboration includes a co-development and co-commercialization agreement for the Company’s selective BRM oncology target, consisting of two programs, and one additional undisclosed oncology target (collectively, the “Joint Programs”). The collaboration also includes three additional discovery targets or programs (collectively, the “Discovery Programs”) for a total of six programs directed at five targets. With respect to the Joint Programs, the Company will lead discovery and early research activities through the successful completion of dose finding toxicity studies for the identified compound, while Lilly will lead development and commercialization activities of the identified compound with participation from the Company in development activities and 50% cost sharing until registrational clinical trials. The Company and Lilly may jointly develop and commercialize the Joint Program compound though the Company may, in its sole discretion, opt-out on a program-by-program basis of further participation in the development and commercialization efforts prior to the first registrational clinical trial. If the Company does not opt-out, Lilly and the Company will continue to share in the costs to further develop and commercialize the Joint Program compound on a worldwide basis, equally share in the U.S. profits on product sales, subject to certain adjustments and receive royalties on sales outside of the United States (“Ex-U.S.”) at royalty rates ranging from low double digits to high twenties. If the Company opts-out of further development and commercialization efforts, it will have no further obligations to share in the development and commercialization costs, will receive royalties rather than profit share on U.S. sales and will receive royalties at a lower rate on Ex-U.S. sales. With respect to the Discovery Programs, the Company will lead discovery and early research activities through the successful completion of dose finding toxicity studies for the identified compounds. The Company may, in its sole discretion, opt-in on a program-by-program basis after the successful completion of dose finding toxicity to participate in the further development and commercialization efforts of the Discovery Program compounds. If the Company opts-in to the development and commercialization of the Discovery Program compounds, it will be eligible to receive milestone payments of up to $10.0 million per program upon specified research and development milestones and up to $180.0 million per program upon achievement of specified regulatory and commercial milestones and will also be eligible to share in the U.S. profits at pre-determined percentages on product sales. The Company would also be eligible to receive tiered Ex-U.S. royalty rates, calculated on a product-by-product and country-by-country basis, on net sales outside of the United States, if any, ranging from low single digits to low double digits, but less then teens. If the Company does not opt-in to further development and commercialization efforts for the Discovery Programs, it will be eligible to receive milestone payments of up to $70.0 million per program upon specified research and development milestones and up to $360.0 million per program upon achievement of specified regulatory and commercial milestones per approved product, if any. The Company would also be eligible to receive tiered royalties on net sales of products worldwide at royalty rates ranging from low single digits to low double digits, but less then teens. Lilly has the right to make substitutions for each of the five targets during the research term of each program, subject to certain limitations. Pursuant to the Lilly Collaboration Agreement, the Company will also participate in joint decision-making through the joint steering committee and subcommittees. Unless terminated earlier, the Lilly Collaboration Agreement will continue on a product-by-product basis until the expiration of all royalty obligations under the Lilly Collaboration Agreement and when neither the Company nor Lilly is developing, commercializing or manufacturing any product under the Lilly Collaboration Agreement. The Company or Lilly may terminate the Lilly Collaboration Agreement upon an uncured material breach by the other party. Lilly may also terminate the Lilly Collaboration Agreement in its entirety or on a target-by-target, program-by-program or product-by-product basis for any reason upon certain notice to the Company. The Company determined that (1) the research activities performed by the Company for both the Joint Programs and the Discovery Programs (2) the development activities and cost sharing for the Joint Program development efforts after dose finding toxicity until registrational clinical trials (3) the research, development, manufacture and commercialization licenses and (4) service on the joint steering committee and subcommittees represent a single performance obligation under the Lilly Collaboration Agreement. The Company determined that Lilly cannot benefit from the licenses separately from the research activities, the development activities until registrational clinical trials and participation on the joint steering committee and subcommittees because these services are specialized and rely on the Company’s expertise such that these activities are highly interrelated and therefore not distinct. Accordingly, the promised goods and services represent one combined performance obligation, and the entire transaction price was allocated to that single combined performance obligation. The performance obligation will be satisfied over time as the Company performs the research activities, participates and shares in the cost of the development activities for the Joint Programs and participates in a joint steering committee and subcommittees to oversee these activities. The Company’s options to share in further development and commercialization efforts via its opt-in/opt-out rights will be assessed and accounted for as separate units of accounting under the relevant guidance if, and when, such options are exercised by the Company. During the third quarter of 2023, the Company has transitioned the BRM Selective inhibitor program into development activities for which Lilly will lead and the Company will partcipate and share in 50% of the costs until registrational trials. Costs incurred will continue to be included in research and development expenses on the condensed consolidated statements of operations and comprehensive loss. As of September 30, 2023, the aggregate amount of the transaction price related to the unsatisfied portion of the performance obligation was $308.4 million, which is expected to be recognized as revenue through 2029 or beyond depending on the timing of certain clinical development activities. As of December 31, 2022, the aggregate amount of the transaction price related to the unsatisfied portion of the performance obligation was $319.8 million. The Company does not expect collaboration revenue to be recognized evenly over this period as it will be recognized on a percentage of completion basis (using a cost-to-cost method) as the Company performs the research and development activities and participates on the joint steering committee and subcommittees, which will likely vary from period to period. In estimating the total costs to satisfy its single performance obligation pursuant to the Lilly Collaboration Agreement, the Company is required to make significant estimates including an estimate of the number of target substitutions Lilly may elect to make and the expected time and expected costs to fulfill the performance obligation. The cumulative effect of revisions to the total estimated costs to complete the Company’s single performance obligation will be recorded in the period in which the changes are identified, and amounts can be reasonably estimated. While such revisions will have no impact on the Company’s cash flows, a significant change in these assumptions and estimates could have a material impact on the timing and amount of revenue recognized in future periods and the classification of deferred revenue between short-term and long-term. In September 2023 the Company re-evaluated its estimates related to the Lilly Collaboration Agreement. As a result of this re-evaluation, expected future costs over the course of the Lilly Collaboration Agreement increased resulting in an adjustment that decreased revenue by $3.2 million for the three months ended September 30, 2023. For the three months ended September 30, 2023 and 2022, the Company had recorded $1.4 million and $5.3 million, respectively, of revenue under the Lilly Collaboration Agreement, which was included in deferred revenue at the beginning of the respective periods. For the nine months ended September 30, 2023 and 2022, the Company had recorded $11.3 million and $13.3 million, respectively, of revenue under the Lilly Collaboration Agreement, which was included in deferred revenue at the beginning of the respective periods. Merck Collaboration Agreement In July 2020, the Company entered into the Merck Collaboration Agreement with Merck, pursuant to which the Company and Merck applied Foghorn’s proprietary Gene Traffic Control platform to discover and develop novel therapeutics. Under the Merck Collaboration Agreement, the Company granted Merck exclusive global rights to develop, manufacture and commercialize drugs that target dysregulation of a single transcription factor. Under the terms of the Merck Collaboration Agreement, the Company and Merck were each responsible to perform certain research activities in accordance with a mutually-agreed upon research plan. Merck could substitute the selected transcription factor during certain stages of the research program, subject to certain limitations. Following completion of the research program, Merck was to be responsible for the development and commercialization of the compounds developed pursuant to the research program and any product containing such compounds. Pursuant to the Merck Collaboration Agreement, the Company would also participate on a joint steering committee. On August 9, 2023 the Company received notice from Merck that it is terminating the Merck Collaboration Agreement effective November 7, 2023. At the time of notice, no material obligations remained under the Merck Collaboration Agreement. As such, the Company recognized the remaining $16.1 million of deferred revenue, related to the original $15.0 million upfront payment and $5.0 million milestone payment received from Merck, in the three months ended September 30, 2023 as collaboration revenue. As of September 30, 2023, there was no remaining performance obligation under the Merck Collaboration Agreement. As of December 31, 2022, the aggregate amount of the transaction price related to the unsatisfied portion of the performance obligation was $17.0 million.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2023
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes For the three and nine months ended September 30, 2023, the Company recorded a provision for income taxes of $0.7 million and $2.2 million, respectively, representing an effective tax rate of 5.4% and 3.1%, respectively. The income tax provision and the effective tax rate is primarily driven by the current federal and state taxes related to the $300.0 million upfront payment for Lilly Collaboration Agreement, which will be recognized as taxable income in the current year, and the required capitalization of research and development costs pursuant to Internal Revenue Code Section 174. As a result, the Company expects to have taxable income in the current year, which will be reduced by utilizing available net operating loss carryforwards and research and development tax credit carryforwards. The Company has evaluated the positive and negative evidence bearing upon its ability to realize the deferred tax assets. Management has considered the Company’s history of cumulative net losses incurred since inception and its lack of commercialization of any products that would generate revenue from product sales and has concluded that it is more likely than not that the Company will not realize the benefits of the deferred tax assets. Accordingly, a full valuation allowance has been established against the net deferred tax assets.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Leases The Company leases office space under a non-cancelable operating lease. There have been no material changes to the Company's lease during the three and nine months ended September 30, 2023. For additional information, see Note 10, Leases , to the consolidated financial statements in the Company's Annual Report on Form 10-K for the year ended December 31, 2022. License agreements The Company has entered into various exclusive and non-exclusive license agreements for certain technologies. Under the terms of these license agreements, the Company could be required to reimburse the licensors for patent expenses and remit amounts in the low single-digit as sales-based royalties upon the occurrence of specific events as outlined in the corresponding license agreements. The Company is also required to make annual license maintenance fees of less than $0.3 million and pay up to $1.1 million in regulatory milestones on each licensed product upon the occurrence of specific events as outlined in one of the license agreements. None of our product candidates utilize technologies covered by these licenses. 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. Legal Proceedings From time to time, the Company may become involved in litigation or other legal proceedings. The Company is not currently a party to any material litigation or legal proceedings.

Related Parties

Related Parties	9 Months Ended
	Sep. 30, 2023
Related Party Transactions [Abstract]
Related Parties	Related PartiesIn October 2015, the Company entered into a five-year consulting agreement with a scientific founder of the Company who is also a shareholder. This agreement was amended and extended to January 1, 2024 and is subject to automatic one-year renewal terms until terminated. During the three months ended September 30, 2023 and 2022, the Company paid the scientific founder a de minimis amount. During the nine months ended September 30, 2023 and 2022, the Company paid the scientific founder $0.1 million. As of September 30, 2023 and December 31, 2022, the Company had less than $0.1 million, respectively, of accounts payable due to the scientific founder.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Basis of presentation	Basis of presentation The Company’s condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”) and pursuant to the rules and regulations of the United States Securities and Exchange Commission for interim financial statements. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. The accompanying condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary. All intercompany accounts and transactions have been eliminated in consolidation. 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”).
Recently issued accounting pronouncements	Recently issued accounting pronouncements From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies that the Company adopts as of the specified effective date. The Company qualifies as an “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012 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 can adopt the new or revised standard at the time nonpublic companies adopt the new or revised standard and can 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 June 2016, the FASB issued ASU No. 2016-13, Financial Instruments – Credit Losses (Topic 326) . The new standard adjusts the accounting for assets held at amortized costs basis by eliminating the probable initial recognition threshold and requires an entity to reflect its current estimate of all expected credit losses as an allowance for credit losses. For nonpublic entities and emerging growth companies that choose to take advantage of the extended transition period, the guidance was initially effective for annual reporting periods beginning after December 15, 2020. However, in November 2019, the FASB issued ASU No. 2019-10, which deferred the effective date for nonpublic entities to annual reporting periods beginning after December 15, 2022, including interim periods within those fiscal years. The Company adopted this as of January 1, 2023 and the adoption had no material impact to the Company’s consolidated financial position, results of operation, or cash flows.

Marketable Securities and Fai_2

Marketable Securities and Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2023
Fair Value Disclosures [Abstract]
Summary of Available for Sale Marketable Securities by Security Type	As of September 30, 2023, available for sale marketable securities by security type consisted of (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value U.S. treasury notes (due within one year) $ 2,997 $ — $ (32) $ 2,965 U.S. government agencies (due within one year) 11,813 — (73) 11,740 Commercial paper (due within one year) 15,815 — (10) 15,805 Corporate notes and bonds (due within one year) 143,589 1 (1,475) 142,115 Corporate notes and bonds (due after one year through two 17,261 — (304) 16,957 Total $ 191,475 $ 1 $ (1,894) $ 189,582 As of December 31, 2022, available for sale marketable securities by security type consisted of (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value U.S. treasury notes (due within one year) $ 7,987 $ — $ (115) $ 7,872 Commercial paper (due within one year) 56,697 2 (301) 56,398 Corporate notes and bonds (due within one year) 139,764 — (1,342) 138,422 Corporate notes and bonds (due after one year through three 93,122 4 (2,234) 90,892 Total $ 297,570 $ 6 $ (3,992) $ 293,584
Summary of Financial Assets and Liabilities Measured at Fair Value on a 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, 2023 Using: Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 69,311 $ — $ — $ 69,311 Commercial paper — 995 — 995 Marketable securities: U.S. treasury notes — 2,965 — 2,965 U.S. government agencies — 11,740 — 11,740 Commercial paper — 15,805 — 15,805 Corporate notes and bonds — 159,072 — 159,072 Total $ 69,311 $ 190,577 $ — $ 259,888 Fair Value Measurements at December 31, 2022 Using: Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 28,077 $ — $ — $ 28,077 U.S. treasury notes — 1,998 — 1,998 Commercial paper — 22,139 — 22,139 Marketable securities: U.S. treasury notes — 7,872 — 7,872 Commercial paper — 56,398 — 56,398 Corporate notes and bonds — 229,314 — 229,314 Total $ 28,077 $ 317,721 $ — $ 345,798

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	9 Months Ended
	Sep. 30, 2023
Property, Plant and Equipment [Abstract]
Summary of Property and Equipment Net	Property and equipment, net consisted of the following (in thousands): September 30, 2023 December 31, 2022 Laboratory equipment $ 6,788 $ 5,884 Furniture and fixtures 815 815 Computer equipment and software 115 100 Leasehold improvements 17,239 17,123 24,957 23,922 Less: Accumulated depreciation and amortization (11,164) (8,611) $ 13,793 $ 15,311

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	9 Months Ended
	Sep. 30, 2023
Payables and Accruals [Abstract]
Summary of Accrued Expenses	Accrued expenses consisted of the following (in thousands): September 30, 2023 December 31, 2022 Accrued external research and development expenses $ 2,967 $ 5,262 Accrued employee compensation and benefits 4,692 4,743 Accrued professional fees 839 678 Other 301 318 $ 8,799 $ 11,001

Common Stock and Net Loss Per_2

Common Stock and Net Loss Per Share (Tables)	9 Months Ended
	Sep. 30, 2023
Equity [Abstract]
Summary of Earnings Per Share Diluted Anti Dilutive Impact	The following common stock equivalents presented based on amounts outstanding at each period end have been excluded from the calculation of diluted net loss per share because including them would have had an anti-dilutive impact: September 30, 2023 2022 Stock options to purchase common stock 9,532,730 7,860,248 Warrants to purchase common stock 18,445 18,445 9,551,175 7,878,693

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2023
Share-Based Payment Arrangement [Abstract]
Summary of Stock-Based Compensation Expense	Stock-based compensation expense was classified in the condensed consolidated statements of operations and comprehensive loss as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2023 2022 2023 2022 Research and development expenses $ 1,776 $ 1,689 $ 5,800 $ 4,784 General and administrative expenses 2,318 2,113 7,335 5,771 $ 4,094 $ 3,802 $ 13,135 $ 10,555

Nature of Business, Going Con_2

Nature of Business, Going Concern and Basis of Presentation (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended						9 Months Ended
	Jan. 31, 2022	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Organization Consolidation And Presentation Of Financial Statements
Net loss		$ 14,345	$ 29,487	$ 30,488	$ 25,769	$ 27,313	$ 26,914	$ 74,320	$ 79,996
Accumulated deficit		447,458						447,458		$ 373,138
Eli Lilly
Organization Consolidation And Presentation Of Financial Statements
Upfront payment received	$ 300,000							300,000
Deferred revenue		$ 308,400						$ 308,400		$ 319,800

Marketable Securities and Fai_3

Marketable Securities and Fair Value Measurements - Summary of Available for Sale Marketable Securities by Security Type (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Amortized Cost	$ 191,475	$ 297,570
Gross Unrealized Gains	1	6
Gross Unrealized Losses	(1,894)	(3,992)
Estimated Fair Value	189,582	293,584
U.S. treasury notes (due within one year)
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Amortized Cost	2,997	7,987
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(32)	(115)
Estimated Fair Value	2,965	7,872
U.S. government agencies (due within one year)
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Amortized Cost	11,813
Gross Unrealized Gains	0
Gross Unrealized Losses	(73)
Estimated Fair Value	11,740
Commercial paper (due within one year)
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Amortized Cost	15,815	56,697
Gross Unrealized Gains	0	2
Gross Unrealized Losses	(10)	(301)
Estimated Fair Value	15,805	56,398
Corporate notes and bonds (due within one year)
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Amortized Cost	143,589	139,764
Gross Unrealized Gains	1	0
Gross Unrealized Losses	(1,475)	(1,342)
Estimated Fair Value	142,115	138,422
Corporate notes and bonds (due after one year through two years)
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Amortized Cost	17,261	93,122
Gross Unrealized Gains	0	4
Gross Unrealized Losses	(304)	(2,234)
Estimated Fair Value	$ 16,957	$ 90,892

Marketable Securities and Fai_4

Marketable Securities and Fair Value Measurements - Summary of Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Marketable securities	$ 189,582	$ 293,584
Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Marketable securities	15,805	56,398
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total	259,888	345,798
Recurring | U.S. treasury notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Marketable securities	2,965	7,872
Recurring | U.S. government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Marketable securities	11,740
Recurring | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Marketable securities	15,805	56,398
Recurring | Corporate notes and bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Marketable securities	159,072	229,314
Recurring | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents	69,311	28,077
Recurring | U.S. treasury notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents		1,998
Recurring | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents	995	22,139
Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total	69,311	28,077
Recurring | Level 1 | U.S. treasury notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Marketable securities	0	0
Recurring | Level 1 | U.S. government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Marketable securities	0
Recurring | Level 1 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Marketable securities	0	0
Recurring | Level 1 | Corporate notes and bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Marketable securities	0	0
Recurring | Level 1 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents	69,311	28,077
Recurring | Level 1 | U.S. treasury notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents		0
Recurring | Level 1 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents	0	0
Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total	190,577	317,721
Recurring | Level 2 | U.S. treasury notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Marketable securities	2,965	7,872
Recurring | Level 2 | U.S. government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Marketable securities	11,740
Recurring | Level 2 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Marketable securities	15,805	56,398
Recurring | Level 2 | Corporate notes and bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Marketable securities	159,072	229,314
Recurring | Level 2 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents	0	0
Recurring | Level 2 | U.S. treasury notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents		1,998
Recurring | Level 2 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents	995	22,139
Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total	0	0
Recurring | Level 3 | U.S. treasury notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Marketable securities	0	0
Recurring | Level 3 | U.S. government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Marketable securities	0
Recurring | Level 3 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Marketable securities	0	0
Recurring | Level 3 | Corporate notes and bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Marketable securities	0	0
Recurring | Level 3 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents	0	0
Recurring | Level 3 | U.S. treasury notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents		0
Recurring | Level 3 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash equivalents	$ 0	$ 0

Property and Equipment, Net - S

Property and Equipment, Net - Summary of Property and Equipment Net (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization
Property plant and equipment including finance right of use assets, gross	$ 24,957	$ 23,922
Less: Accumulated depreciation and amortization	(11,164)	(8,611)
Property and equipment, net	13,793	15,311
Laboratory equipment
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization
Property plant and equipment including finance right of use assets, gross	6,788	5,884
Furniture and fixtures
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization
Property plant and equipment including finance right of use assets, gross	815	815
Computer equipment and software
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization
Property plant and equipment including finance right of use assets, gross	115	100
Leasehold improvements
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization
Property plant and equipment including finance right of use assets, gross	$ 17,239	$ 17,123

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Property, Plant and Equipment [Abstract]
Depreciation and amortization expense	$ 900	$ 900	$ 2,599	$ 2,473

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Accrued external research and development expenses	$ 2,967	$ 5,262
Accrued employee compensation and benefits	4,692	4,743
Accrued professional fees	839	678
Other	301	318
Total	$ 8,799	$ 11,001

Common Stock and Net Loss Per_3

Common Stock and Net Loss Per Share - Narrative (Details)	Sep. 30, 2023 vote
Equity [Abstract]
Voting rights per share (per share)	1

Common Stock and Net Loss Per_4

Common Stock and Net Loss Per Share - Summary of Earnings Per Share Diluted Anti Dilutive Impact (Details) - shares	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive shares excluded from the calculation of earnings per share (in shares)	9,551,175	7,878,693
Stock options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive shares excluded from the calculation of earnings per share (in shares)	9,532,730	7,860,248
Warrants to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive shares excluded from the calculation of earnings per share (in shares)	18,445	18,445

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($) $ in Millions			3 Months Ended		9 Months Ended
	Jan. 01, 2023	Oct. 21, 2020	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Share-based Payment Arrangement
Number of shares authorized (in shares)	1,184,497
Unrecognized compensation costs related to unvested options and unvested restricted stock			$ 32.8		$ 32.8
Weighted average period of unrecognized compensation costs					2 years 4 months 24 days
2020 Equity Incentive Plan
Share-based Payment Arrangement
Number of shares authorized (in shares)			2,200,000		2,200,000
Common stock shares available for grant (in shares)			1,121,971		1,121,971
Percentage of automatic annual increase in number of shares					4%
Number of additional shares authorized (in shares)	1,672,137
Vesting period (years)					4 years
Stock option expiry period (years)					10 years
2016 Stock Incentive Plan
Share-based Payment Arrangement
Number of shares authorized (in shares)			5,078,295		5,078,295
2020 Employee Stock Purchase Plan
Share-based Payment Arrangement
Number of shares authorized (in shares)		360,000
Percentage of automatic annual increase in number of shares		1%
Number of additional shares authorized (in shares)	418,034
Maximum aggregate number of shares added to plan (in shares)		3,220,520
Percentage of payroll deductions			15%		15%
Discount of shares rate, percent					15%
Share-based payment arrangement, expense			$ 0	$ 0	$ 0.1	$ 0

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Share-based Payment Arrangement
Stock-based compensation expense	$ 4,094	$ 3,802	$ 13,135	$ 10,555
Research and development expenses
Share-based Payment Arrangement
Stock-based compensation expense	1,776	1,689	5,800	4,784
General and administrative expenses
Share-based Payment Arrangement
Stock-based compensation expense	$ 2,318	$ 2,113	$ 7,335	$ 5,771

Collaboration Agreements (Detai

Collaboration Agreements (Details) $ in Thousands		1 Months Ended	3 Months Ended		9 Months Ended
	Aug. 09, 2023 USD ($)	Dec. 31, 2021 USD ($) target program	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)	Jul. 31, 2020 USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative
Collaboration revenue			$ 17,478	$ 6,634	$ 28,386	$ 15,044
Eli Lilly
Collaborative Arrangement and Arrangement Other than Collaborative
Number of additional targets | target		3
Number of programs | program		6
Number of targets | target		5
Cost sharing allocation		50%	50%		50%
Deferred revenue			$ 308,400		$ 308,400		$ 319,800
Collaboration revenue			1,400	5,300	11,300	13,300
Eli Lilly | Research Development And Regulatory | Adjustments
Collaborative Arrangement and Arrangement Other than Collaborative
Collaboration revenue			(3,200)
Eli Lilly | Sales Based Milestone
Collaborative Arrangement and Arrangement Other than Collaborative
Amount receivable for achievement of milestones		$ 180,000
Optout milestone receivable upon achievement		360,000
Eli Lilly | Maximum | Research Development And Regulatory
Collaborative Arrangement and Arrangement Other than Collaborative
Amount receivable for achievement of milestones		10,000
Optout milestone receivable upon achievement		$ 70,000
Merck
Collaborative Arrangement and Arrangement Other than Collaborative
Unsatisfied portion of the performance obligation			0		0		$ 17,000
Merck | Merck Collaboration Agreement
Collaborative Arrangement and Arrangement Other than Collaborative
Collaboration revenue	$ 16,100		16,100	$ 1,300	$ 17,000	$ 1,700
Merck | Merck Collaboration Agreement | Upfront Payments
Collaborative Arrangement and Arrangement Other than Collaborative
Deferred revenue								$ 15,000
Merck | Merck Collaboration Agreement | Milestone Payment
Collaborative Arrangement and Arrangement Other than Collaborative
Collaboration revenue			$ 5,000

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Jan. 31, 2022	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Income Tax
Provision for income taxes		$ 738	$ 0	$ 2,240	$ 0
Effective income tax rate (percent)		5.40%		3.10%
Eli Lilly
Income Tax
Upfront payment received	$ 300,000			$ 300,000

Commitments and Contingencies (

Commitments and Contingencies (Details) - Stanford License Agreement - Maximum $ in Millions	9 Months Ended
	Sep. 30, 2023 USD ($)
Commitments And Contingencies
Annual license maintenance fees	$ 0.3
Milestones payable upon event	$ 1.1

Related Parties (Details)

Related Parties (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Oct. 31, 2015	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Related Party Transaction
Payments made to related party under service agreement		$ 0	$ 0	$ 100	$ 100
Accounts payable		$ 6,496		$ 6,496		$ 5,414
Related Party | Scientific Founder
Related Party Transaction
Service agreement term	5 years
Service agreement, renewal term	1 year
Accounts payable						$ 100