Pliant Therapeutics (PLRX) 10-Q 6 May 24 2024 Q1 Quarterly report Financial data

Cover

Cover - shares	3 Months Ended
	Mar. 31, 2024	May 01, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Document Transition Report	false
Entity File Number	001-39303
Entity Registrant Name	PLIANT THERAPEUTICS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-4272481
Entity Address, Address Line One	260 Littlefield Avenue
Entity Address, City or Town	South San Francisco,
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94080
City Area Code	650
Local Phone Number	481-6770
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Trading Symbol	PLRX
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		60,325,832
Amendment Flag	false
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Entity Central Index Key	0001746473
Current Fiscal Year End Date	--12-31

Condensed Balance Sheets (Unaud

Condensed Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	[1]
Current assets
Cash and cash equivalents	$ 114,297	$ 63,234
Short-term investments	368,092	431,011
Prepaid expenses and other current assets (Note 5)	7,509	11,257
Total current assets	489,898	505,502
Property and equipment, net	5,605	3,567
Operating lease right-of-use assets (Note 14)	24,228	1,211
Restricted cash	1,482	1,482
Other non-current assets	392	392
Total assets	521,605	512,154
Current liabilities
Accounts payable	7,327	4,531
Accrued research and development	16,423	12,456
Accrued liabilities (Note 6)	5,868	10,219
Operating lease liabilities, current (Note 14)	773	1,318
Total current liabilities	30,391	28,524
Operating lease liabilities, non-current (Note 14)	23,880	0
Long-term debt (Note 7)	30,002	10,054
Total liabilities	84,273	38,578
Commitments and Contingencies (Note 13)
Stockholders’ equity
Preferred stock, $0.0001 par value per share; 10,000,000 shares authorized at March 31, 2024 and December 31, 2023, and none issued or outstanding at March 31, 2024 and December 31, 2023 (Note 9)	0	0
Common stock, $0.0001 par value per share; 300,000,000 shares authorized at March 31, 2024 and December 31, 2023; and 60,318,542 and 59,921,002 shares issued and outstanding at March 31, 2024 and December 31, 2023, respectively; (Note 10)	6	6
Additional paid-in capital	984,518	972,973
Accumulated deficit	(546,703)	(499,748)
Accumulated other comprehensive (loss) gain	(489)	345
Total stockholders’ equity	437,332	473,576
Total liabilities and stockholders’ equity	$ 521,605	$ 512,154
[1] The condensed balance sheet as of December 31, 2023 has been derived from the audited financial statements as of that date .

Condensed Balance Sheets (Una_2

Condensed Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Mar. 31, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Preferred stock, par value (USD per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (USD per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock, shares issued (in shares)	60,318,542	59,921,002
Common stock, shares outstanding (in shares)	60,318,542	59,921,002

Condensed Statements of Operati

Condensed Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Statement [Abstract]
Revenue	$ 0	$ 1,332
Operating expenses:
Research and development	(37,146)	(29,273)
General and administrative	(15,246)	(14,154)
Total operating expenses	(52,392)	(43,427)
Loss from operations	(52,392)	(42,095)
Interest and other income (expense), net	5,882	4,858
Interest expense	(445)	(311)
Net loss	$ (46,955)	$ (37,548)
Earnings Per Share [Abstract]
Basic (USD per share)	$ (0.78)	$ (0.67)
Diluted (USD per share)	$ (0.78)	$ (0.67)
Weighted Average Number of Shares Outstanding, Diluted [Abstract]
Shares used in computing net loss per share - basic (in shares)	60,180,921	56,057,603
Shares used in computing net loss per share - diluted (in shares)	60,180,921	56,057,603
Comprehensive loss:
Net loss	$ (46,955)	$ (37,548)
Net unrealized (loss) gain on short-term investments	(834)	627
Total other comprehensive (loss) gain	(834)	627
Comprehensive loss	$ (47,789)	$ (36,921)

Condensed Statements of Stockho

Condensed Statements of Stockholders’ Equity (Unaudited) - USD ($) $ in Thousands	Total		Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Gain/(Loss)	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2022			48,941,254
Beginning balance at Dec. 31, 2022	$ 313,342		$ 5	$ 653,707	$ (1,958)	$ (338,412)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued in a public offering, net of offering expenses (in shares)			9,583,334
Common stock issued in a public offering, net of offering expenses	269,915		$ 1	269,914
Issuance of common stock under benefit plans (in shares)			454,314
Issuance of common stock under benefit plans	3,661			3,661
Stock-based compensation expense	11,923			11,923
Net unrealized (loss) gain on short-term investments	627				627
Net loss	(37,548)					(37,548)
Ending balance (in shares) at Mar. 31, 2023			58,978,902
Ending balance at Mar. 31, 2023	$ 561,920		$ 6	939,205	(1,331)	(375,960)
Beginning balance (in shares) at Dec. 31, 2023	59,921,002		59,921,002
Beginning balance at Dec. 31, 2023	$ 473,576	[1]	$ 6	972,973	345	(499,748)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under benefit plans (in shares)			397,540
Issuance of common stock under benefit plans	1,879			1,879
Stock-based compensation expense	9,666			9,666
Net unrealized (loss) gain on short-term investments	(834)				(834)
Net loss	$ (46,955)					(46,955)
Ending balance (in shares) at Mar. 31, 2024	60,318,542		60,318,542
Ending balance at Mar. 31, 2024	$ 437,332		$ 6	$ 984,518	$ (489)	$ (546,703)
[1] The condensed balance sheet as of December 31, 2023 has been derived from the audited financial statements as of that date .

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash flows from operating activities
Net loss	$ (46,955)	$ (37,548)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	513	452
Stock-based compensation expense	9,666	11,923
Non-cash operating lease expense	681	609
Net amortization (accretion) on short-term investments and debt	1,091	(2,584)
Changes in operating assets and liabilities:
Accounts receivable	0	(1,314)
Prepaid expenses and other current assets	3,749	(476)
Accounts payable	2,257	(144)
Accrued liabilities	(910)	(538)
Operating lease liabilities	(363)	(656)
Net cash used in operating activities	(30,271)	(30,276)
Cash flows from investing activities
Purchase of short-term investments	(52,375)	(276,620)
Maturity of short-term investments	113,413	102,575
Purchase of property and equipment	(1,492)	(163)
Net cash used in (provided by) investing activities	59,546	(174,208)
Cash flows from financing activities
Proceeds from issuances of common stock under benefit plans	1,879	3,661
Proceeds from term loan, net	19,909	0
Payment of offering costs	0	(586)
Proceeds from sale of common stock in a public offering	0	270,251
Net cash provided by financing activities	21,788	273,326
Net increase in cash and cash equivalents	51,063	68,842
Cash and cash equivalents and restricted cash at beginning of period	64,716	33,685
Cash, cash equivalents and restricted cash at end of period	115,779	102,527
Supplemental disclosures of cash flow information:
Cash paid for interest	501	282
Reconciliation of cash, cash equivalents, and restricted cash reported in the balance sheets
Cash and cash equivalents	114,297	102,527
Restricted cash	1,482	0
Total cash, cash equivalents, and restricted cash shown in the statements of cash flows	115,779	102,527
Supplemental disclosures of noncash investing and financing activities:
Net unrealized (loss) gain on short-term investments	(834)	636
Purchase of property and equipment in accounts payable and accrued liabilities	1,059	0
Supplemental disclosures of cash flow information related to leases:
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 23,698	$ 0

Organization and Description of

Organization and Description of Business	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	Organization and Description of Business Pliant Therapeutics, Inc. (the “Company” or "Pliant" or “we” or “our” or “us”) is a late stage biopharmaceutical company focused on discovering and developing novel therapies for the treatment of fibrosis with an initial focus on treating fibrosis by inhibiting integrin-mediated activation of TGF-ß. Fibrosis refers to the abnormal thickening and scarring of connective tissue due to the production and deposition of excess collagen in the extra-cellular matrix. Fibrosis can occur in many different tissues including lung, liver, kidney, muscle, skin and the GI tract, and often causes severe and debilitating disease leading to organ failure. The Company is located in South San Francisco, California, and was incorporated in the state of Delaware in June 2015. Public Offering In January 2023, the Company completed a public offering of 9,583,334 shares of common stock, including the exercise in full of the underwriters' option to purchase 1,250,000 additional shares of common stock. The shares were offered at a price of $30.00 per share, resulting in aggregate proceeds of approximately $269.8 million, net of underwriting discounts, commissions and offering expenses payable by us.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The accompanying unaudited interim condensed financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and follow the requirements of the Securities and Exchange Commission (“SEC”), for interim financial reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP have been condensed or omitted, and accordingly the unaudited interim condensed financial statements do not include all of the information and notes required by U.S. GAAP for complete financial statements. These unaudited interim condensed financial statements have been prepared on the same basis as our annual financial statements and, in the opinion of management, reflect all adjustments (consisting only of normal recurring adjustments) that are necessary for a fair presentation of the Company's financial information. The results of operations for the three months ended March 31, 2024 are not necessarily indicative of the results to be expected for the year ending December 31, 2024 or for any other interim period or for any other future year. The financial information included herein should be read in conjunction with the audited financial statements and related notes in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023, filed with the SEC on February 27, 2024 (the “2023 10-K”). Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, and expenses as well as the disclosure of contingent assets and liabilities as of and during the reporting period. The Company bases its estimates and assumptions on historical experience when available and on various factors that it believes to be reasonable under the circumstances. Significant estimates and assumptions reflected in these financial statements include, but are not limited to, stock-based compensation expense, operating lease right-of-use (“ROU”) assets and liabilities, accruals and prepayments for research and development costs, income taxes and uncertain tax positions. The Company assesses estimates on an ongoing basis, however, actual results could materially differ from those estimates. Significant Accounting Policies There have been no significant changes to the accounting policies during the three months ended March 31, 2024, as compared to the significant accounting policies described in Note 2 of the "Notes to the Financial Statements" in the Company's audited financial statements included in its 2023 10-K. Recently Announced Accounting Pronouncements In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which requires public entities to disclose information about their reportable segments’ significant expenses on an interim and annual basis. ASU 2023-07 is effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. Entities must adopt the changes to the segment reporting guidance on a retrospective basis, and early adoption is permitted. The Company is currently evaluating the impact of this standard on its disclosures and will adopt the ASU for its 2024 10-K. In December 2023, the FASB issued ASU 2023-09 "Income Taxes (Topic 740): Improvements to Income Tax Disclosures", which expands disclosures in an entity’s income tax rate reconciliation table and regarding cash taxes paid both in the U.S. and foreign jurisdictions. The Company is currently evaluating the impact of this standard on its disclosures and will adopt the ASU for its 2025 10-K.

Financial Instruments

Financial Instruments	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Financial Instruments	Financial Instruments The Company’s short-term investments consist of U.S. Treasury securities, U.S. government agency securities and highly rated, investment-grade corporate debt securities with original maturities beyond three months at the date of purchase. The Company has classified and accounted for its short-term investments as available-for-sale securities as the Company may sell these securities at any time even prior to maturity and such investments represent cash available for current operations. As a result, short-term investments may include securities with maturities beyond twelve months that are classified within current assets in the Balance Sheets. The Company’s short-term investments classified as available-for-sale are carried at fair market value with unrealized gains or losses recognized in the statements of operations and comprehensive loss. The Company’s cash equivalent Money Market Funds are classified as Level 1 in the fair value hierarchy because they are valued using quoted active market prices. The fair value of the Company’s U.S. Treasury securities, U.S. government agency securities and corporate debt securities are classified as Level 2 because they are valued using observable inputs to quoted market prices other than Level 1 prices, benchmark yields, reported trades, broker/dealer quotes or alternative pricing sources with reasonable levels of price transparency and include U.S. government agency securities, U.S. Treasury securities and corporate debt securities. There were no assets or liabilities recorded at fair value to the condensed balance sheets using Level 3 inputs as of March 31, 2024 and as of December 31, 2023. The following tables show the Company’s Money Market Funds, U.S. Treasury securities, U.S. government agency securities and corporate debt securities by significant investment category as of March 31, 2024 and December 31, 2023 (in thousands): As of March 31, 2024 As of December 31, 2023 Adjusted Unrealized Unrealized Market Adjusted Unrealized Unrealized Market Money Market Funds Level 1 $ 66,387 $ — $ — $ 66,387 $ 57,241 $ — $ — $ 57,241 U.S. Treasury securities Level 2 23,493 — (17) 23,476 27,250 46 (8) 27,288 U.S. Government agency securities Level 2 122,121 107 (234) 121,994 133,655 563 (132) 134,086 Corporate debt securities Level 2 239,912 43 (389) 239,566 269,761 213 (337) 269,637 Total financial assets $ 451,913 $ 150 $ (640) $ 451,423 $ 487,907 $ 822 $ (477) $ 488,252 As of March 31, 2024 As of December 31, 2023 Adjusted Unrealized Unrealized Market Adjusted Unrealized Unrealized Market Classified as: Cash equivalents $ 83,336 $ — $ (5) $ 83,331 $ 57,241 $ — $ — $ 57,241 Short-term investments 368,577 150 (635) 368,092 430,666 822 (477) 431,011 Total $ 451,913 $ 150 $ (640) $ 451,423 $ 487,907 $ 822 $ (477) $ 488,252 The Company may sell certain of its short-term securities prior to their stated maturities for reasons including, but not limited to, managing liquidity, credit risk, duration and asset allocation. There were no liabilities measured at fair value on a recurring basis as of March 31, 2024 and December 31, 2023. The Company evaluates transfers between levels at the end of each reporting period and there have been no transfers between fair value measurement levels during the three months ended March 31, 2024. In addition, there were no assets or liabilities measured at fair value on a non-recurring basis as of March 31, 2024 and December 31, 2023. The Company records interest income, accretion income and amortization expense on Money Market Funds and U.S. Treasury, U.S. government agency and corporate debt securities to interest and other income (expense), net in its condensed statement of operations and comprehensive loss.

Property and Equipment, net

Property and Equipment, net	3 Months Ended
	Mar. 31, 2024
Property, Plant and Equipment [Abstract]
Property and Equipment, net	Property and Equipment, net Property and equipment, net consisted of the following (in thousands): As of March 31, 2024 As of December 31, 2023 Laboratory equipment 10,423 10,410 Leasehold improvements 1,964 1,663 Furniture and fixtures 1,728 — Computer equipment and software 620 124 Construction-in-progress 65 52 Total property and equipment, gross 14,800 12,249 Less: Accumulated depreciation (9,195) (8,682) Total property and equipment, net 5,605 3,567

Prepaid Expenses and Other Curr

Prepaid Expenses and Other Current Assets	3 Months Ended
	Mar. 31, 2024
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid Expenses and Other Current Assets	Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consisted of the following (in thousands): As of March 31, 2024 As of December 31, 2023 Prepaid research and development 2,540 3,403 Prepaid insurance 769 1,131 Prepaid licenses 1,274 2,454 Interest receivable 2,315 2,997 Other 611 1,272 Total prepaid expenses and other current assets 7,509 11,257

Accrued Liabilities

Accrued Liabilities	3 Months Ended
	Mar. 31, 2024
Accrued Liabilities and Other Liabilities [Abstract]
Accrued Liabilities	Accrued Liabilities Accrued liabilities consisted of the following (in thousands): As of March 31, 2024 As of December 31, 2023 Accrued compensation and benefits 4,541 $ 9,042 Other accrued liabilities 1,327 1,177 Total accrued liabilities $ 5,868 $ 10,219 Accrued compensation and benefits consist primarily of accrued bonuses and accrued vacation.

Long-term Debt

Long-term Debt	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
Long-term Debt	Long-term Debt In May 2022, as amended in October 2022, we entered into a term loan facility (the “Oxford Loan Agreement”) with Oxford Finance LLC (the "Lender") for up to $100.0 million. In connection with the Oxford Loan Agreement, we granted a security interest in substantially all of our current and future assets. There are no warrants or financial covenants associated with the Oxford Loan Agreement. At closing, we entered into a term loan for $10.0 million and we decided not to draw upon the additional $65.0 million that became available to us over the course of 2023 as certain conditions related to the development of bexotegrast and one of our preclinical product candidates were satisfied. As of December 31, 2023, the time period to draw upon the additional $65.0 million had lapsed. On March 11, 2024, we entered into an Amended and Restated Loan and Security Agreement (the “Amended Loan Agreement”) with the Lender to borrow a series of term loans up to an aggregate principal amount of $150.0 million (the “Term Loans”), of which $50.0 million is subject to the Lender’s sole discretion. Pursuant to the Amended Loan Agreement, we drew an initial Term Loan of $30.0 million, inclusive of $10.0 million in principal amount previously outstanding under the Oxford Loan Agreement. We may borrow up to an additional $70.0 million of Term Loans at our option upon the satisfaction of certain conditions related to the development of bexotegrast. In connection with the Amended Loan Agreement, the Company granted the Lender a security interest in substantially all of the Company’s assets now owned or hereafter acquired, excluding intellectual property to the extent the aggregate amount of Term Loans advanced and outstanding does not exceed $50.0 million (but including the right to payments and proceeds of intellectual property) and certain customary exceptions. The principal amount outstanding under the Term Loans will accrue interest at a floating per annum rate equal to (i) the greater of (a) 1-month term Chicago Mercantile Exchange (“CME”) Term Secured Overnight Financing Rate (“SOFR”) on the last business day of the month that immediately precedes the month in which the interest will accrue and (b) three and one-half percent (3.50%) plus (ii) five and one-quarter percent (5.25%), subject to an agreed upon floor of 8.75%. Beginning on July 1, 2028, which may be extended to July 1, 2029 (subject to certain conditions set forth in the Amended Loan Agreement), the Company is required to repay the Term Loans in consecutive equal monthly payments of principal, together with applicable interest, in arrears. All unpaid principal and accrued and unpaid interest with respect to each Term Loan will be due and payable in full on March 1, 2029, which may be extended to March 1, 2030 (subject to certain conditions set forth in the Amended Loan Agreement). The Company will be required to make a final payment of 5.50% (or 7.25% if the amortization date of the Term Loans has been extended to July 1, 2029 (as discussed above)) of the original principal amount of the Term Loans that were drawn, payable at maturity or upon any earlier acceleration or prepayment of the Term Loans. The Company may prepay the Term Loans in whole or in part, subject to a prepayment fee equal to (i) if prepaid on or before the first anniversary date of the funding date of such Term Loan, 3.00% of the principal amount of the applicable Term Loan prepaid, (ii) if prepaid after the first anniversary and on or before the second anniversary of the funding date of such Term Loan, 2.00% of the principal amount of the applicable Term Loan prepaid, and (iii) if prepaid after the second anniversary and on or before the third anniversary of the funding date of such Term Loan prepaid, 1.00% of the principal amount of the applicable Term Loan prepaid. The Agreement contains representations and warranties, affirmative, and negative covenants, and events of default that are customary for loans of this type. The occurrence of an event of default could result in the acceleration of the obligations under the Amended Loan Agreement, termination of the Term Loan commitments and the right by the Lender to foreclose on the collateral securing the obligations. During the existence of an event of default, the Term Loans would accrue interest at a rate per annum equal to 5.00% above the otherwise applicable interest rate. The estimated fair value of the term loan as of March 31, 2024 was measured using Level 3 inputs and approximates the carrying value recorded to the balance sheet. The effective interest rate for the term loan is 11.93% and interest expense during the three months ended March 31, 2024 and 2023 was $0.44 million and $0.30 million, respectively. Future maturities of debt as of March 31, 2024 are as follows (in thousands): As of March 31, 2024 2028 $ 20,000 2029 10,000 Thereafter — Total payments 30,000 Less: unamortized debt issuance costs (191) Accretion of final payment 193 Total $ 30,002

Novartis Collaboration and Lice

Novartis Collaboration and License Agreement ("the Novartis Agreement")	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Novartis Collaboration and License Agreement ("the Novartis Agreement")	Novartis Collaboration and License Agreement (the "Novartis Agreement") In 2019, we entered into the Novartis Agreement with Novartis Institutes for BioMedical Research, Inc. (“Novartis”) for the development and commercialization of our preclinical product candidate, PLN-1474, and up to three additional integrin research targets. We assessed the Novartis Agreement in accordance with ASC 606 and determined that Novartis was a customer and identified the following performance obligations: (1) to provide worldwide license rights to PLN-1474, (2) to provide research and development services for PLN-1474, (3) to provide non-exclusive license rights to integrin research targets, and (4) to provide research and development services on integrin research targets. On February 17, 2023, Novartis exercised their right to terminate the Novartis Agreement. The termination took effect on April 18, 2023, and effective upon the termination, all rights and licenses granted to Novartis under the Novartis Agreement, including PLN-1474, the related investigational new drug (“IND”), and the validated research target, reverted back to us. The payment obligations of Novartis with respect to future milestones, royalties and research and development funding were also terminated.

Preferred Stock

Preferred Stock	3 Months Ended
	Mar. 31, 2024
Temporary Equity Disclosure [Abstract]
Preferred Stock	Preferred Stock Under the Company’s Amended and Restated Certificate of Incorporation, the Company is authorized to issue two classes of shares: preferred stock and common stock. The preferred stock may be issued in series, and the Company’s board of directors is authorized to determine the rights, preferences, and terms of each series. These rights, preferences and terms could include dividend rights, conversion rights, voting rights, terms of redemptions, liquidation preferences and sinking fund terms. As of March 31, 2024 and December 31, 2023, the Company was authorized to issue 10,000,000 shares of preferred stock and there was no outstanding preferred stock as of March 31, 2024 and December 31, 2023. As of March 31, 2024 and December 31, 2023, the Company was authorized to issue 300,000,000 shares of common stock at a par value of $0.0001 per share. The common stock has the following rights and privileges: Voting The holders of shares of common stock are entitled to one vote for each share of common stock held at any meeting of stockholders and at the time of any written action in lieu of a meeting. Dividends The holders of shares of common stock are entitled to receive dividends, when declared by the Company’s board of directors. Cash dividends may not be declared or paid to holders of shares of common stock until all unpaid dividends on preferred stock have been paid in accordance with their terms. No dividends have been declared or paid by the Company since its inception. The terms of the Oxford Loan Agreement restrict our ability to declare and pay dividends. Liquidation Subject to the preferential rights of holders of preferred stock then outstanding, the holders of shares of common stock are entitled to share ratably in the Company’s remaining assets available for distribution to its stockholders in the event of any voluntary or involuntary liquidation, dissolution or winding up of the Company. Shares reserved for future issuance As of March 31, As of December 31, 2023 Outstanding stock option awards 7,659,860 6,953,487 Vesting of RSUs 1,201,724 874,748 Vesting of PSUs* 282,345 328,752 Shares of common stock available for future grants under the 2020 Stock Option and Incentive Plan 4,562,694 2,882,239 Shares of common stock available for future issuance under the 2020 Employee Stock Purchase Plan 1,336,085 805,756 Shares of common stock available for future issuance under the 2022 Inducement Plan 700,000 700,000 Total shares reserved for future issuance 15,742,708 12,544,982 *PSUs granted and outstanding based on target level of achievement of 100%.

Common Stock

Common Stock	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
Common Stock	Preferred Stock Under the Company’s Amended and Restated Certificate of Incorporation, the Company is authorized to issue two classes of shares: preferred stock and common stock. The preferred stock may be issued in series, and the Company’s board of directors is authorized to determine the rights, preferences, and terms of each series. These rights, preferences and terms could include dividend rights, conversion rights, voting rights, terms of redemptions, liquidation preferences and sinking fund terms. As of March 31, 2024 and December 31, 2023, the Company was authorized to issue 10,000,000 shares of preferred stock and there was no outstanding preferred stock as of March 31, 2024 and December 31, 2023. As of March 31, 2024 and December 31, 2023, the Company was authorized to issue 300,000,000 shares of common stock at a par value of $0.0001 per share. The common stock has the following rights and privileges: Voting The holders of shares of common stock are entitled to one vote for each share of common stock held at any meeting of stockholders and at the time of any written action in lieu of a meeting. Dividends The holders of shares of common stock are entitled to receive dividends, when declared by the Company’s board of directors. Cash dividends may not be declared or paid to holders of shares of common stock until all unpaid dividends on preferred stock have been paid in accordance with their terms. No dividends have been declared or paid by the Company since its inception. The terms of the Oxford Loan Agreement restrict our ability to declare and pay dividends. Liquidation Subject to the preferential rights of holders of preferred stock then outstanding, the holders of shares of common stock are entitled to share ratably in the Company’s remaining assets available for distribution to its stockholders in the event of any voluntary or involuntary liquidation, dissolution or winding up of the Company. Shares reserved for future issuance As of March 31, As of December 31, 2023 Outstanding stock option awards 7,659,860 6,953,487 Vesting of RSUs 1,201,724 874,748 Vesting of PSUs* 282,345 328,752 Shares of common stock available for future grants under the 2020 Stock Option and Incentive Plan 4,562,694 2,882,239 Shares of common stock available for future issuance under the 2020 Employee Stock Purchase Plan 1,336,085 805,756 Shares of common stock available for future issuance under the 2022 Inducement Plan 700,000 700,000 Total shares reserved for future issuance 15,742,708 12,544,982 *PSUs granted and outstanding based on target level of achievement of 100%.

Equity Incentive Plans and Stoc

Equity Incentive Plans and Stock-Based Compensation	3 Months Ended
	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
Equity Incentive Plans and Stock-Based Compensation	Equity Incentive Plans and Stock-Based Compensation In 2015, the Company's board of directors adopted the 2015 Equity Incentive Plan, as amended in 2018, 2019 and 2020 (the “2015 Plan”), which provided for the grant of incentive stock options, nonqualified stock options or other awards including stock appreciation rights and restricted stock awards to the Company’s employees, officers, directors, advisors, and consultants. In May 2020, the board of directors adopted the 2020 Stock Option and Incentive Plan (the “2020 Plan”) and suspended the 2015 Plan. Awards outstanding under either the 2015 Plan or 2020 Plan that are cancelled, expire or otherwise terminated subsequent to May 2020 will become available for issuance as common stock under the 2020 Plan. Additionally, the 2020 Plan is subject to automatic increases on January 1 of each year beginning January 1, 2021. The number of shares added each January 1 will be equal to the lesser of: (i) 5% of the outstanding shares on the immediately preceding December 31 or (ii) such amount as determined by the compensation committee of the board of directors. The 2020 Plan provides for the grant of incentive stock options, nonqualified stock options or other awards including stock appreciation rights, restricted stock awards and restricted stock units to the Company’s employees, officers, directors, advisors and consultants. As of March 31, 2024, the 2020 Plan had 4,562,694 shares of common stock available for future issuance. In 2022, the board of directors adopted the 2022 Inducement Plan ( “Inducement Plan”), under which the Company may grant nonqualified stock options or other awards including stock appreciation rights and restricted stock awards. As of March 31, 2024, 700,000 shares of common stock were available for issuance. Options under the 2020 Plan and Inducement Plan may be granted for periods of up to 10 years and at prices no less than the market price of the Company’s common stock on the date of grant, provided, however, that the exercise price of an incentive stock option granted to a 10% shareholder shall not be less than 110% of the fair value of the shares on the date of grant and the option is not exercisable after the expiration of five years from the date of grant. Incentive Stock Options and Nonqualified Stock Options Stock options issued under either the 2015 Plan, the 2020 Plan or the Inducement Plan generally vest over four years and expire ten years from the date of grant. Certain options provide for accelerated vesting if there is a change in control, as defined in the respective plans. The Company used Black-Scholes option pricing model to estimate stock-based compensation expense for stock option awards with the following assumptions: Three months ended March 31, 2024 2023 Expected volatility 85.28% - 86.42% 80.97% - 81.41% Risk-free interest rate 4.04% - 4.28% 3.42% - 4.18% Expected dividend — — Expected term (in years) 5.99 - 6.06 5.77 - 6.08 Underlying common stock fair value $15.19 - $17.44 $21.94 - $34.65 The Company granted 1,338,465 stock options under the 2020 Plan during the three months ended March 31, 2024. A summary of option activity under the 2015 Plan and the 2020 Plan is as follows: Number Weighted- Weighted- Aggregate Outstanding as of December 31, 2023 6,953,487 $ 17.95 7.70 $ 32,646 Granted 1,338,465 $ 17.29 Exercised (118,573) $ 8.01 Forfeited (513,519) $ 16.87 Outstanding as of March 31, 2024 7,659,860 $ 18.06 7.83 $ 18,505 Exercisable as of March 31, 2024 7,659,860 $ 18.06 7.83 $ 18,505 Vested and expected to vest as of March 31, 2024 3,651,242 $ 15.84 6.70 $ 15,456 As of March 31, 2024, there were $53.9 million of unrecognized compensation costs that are expected to be recognized over the weighted-average period of 2.8 years related to stock options. Aggregate intrinsic value represents the difference between the fair value of the underlying common stock and the exercise price as of March 31, 2024. The weighted-average grant date fair value of options granted during the three months ended March 31, 2024 was $17.29 per share. Restricted Stock Units The service-based condition for restricted stock units (“RSUs”) is generally satisfied over two years or three years. The following table sets forth the outstanding RSUs and related activity for the three months ended March 31, 2024 Restricted Stock Units Weighted Average Grant Date Fair Value Unvested and outstanding as of December 31, 2023 874,748 $ 29.85 Granted 594,336 $ 17.44 Released (210,085) $ 34.65 Forfeited (57,275) $ 27.88 Unvested and outstanding as of March 31, 2024 1,201,724 $ 22.97 As of March 31, 2024, the Company had $22.9 million of unrecognized stock-based compensation expense related to outstanding RSUs expected to be recognized over a weighted-average period of 2.0 years. Performance-Based Restricted Stock Units Performance-based restricted stock units (“PSUs”) vest upon the achievement of market and performance conditions. Market conditions include the Company's total shareholder return (“TSR”) relative to the NASDAQ Biotechnology Index over the term of the award ending on June 30, 2024. Additionally, the number of shares of common stock issued upon vesting will range from 0% to 200% of the PSUs based on achievement of certain targets. The fair value of the TSR PSUs were derived from a Monte Carlo simulation model that used the following key assumptions: Valuation date share price $ 17.57 Award term (years) 1.92 Volatility 70.62 % Correlation coefficient 0.3508 Average peer group volatility 79.69 % Average peer group correlation coefficient 0.4397 Risk-free interest rate 2.84 % The following table sets forth the outstanding PSUs associated with TSR goal and related activity during the three months ended March 31, 2024: Performance Stock Units Weighted Average Grant Date Fair Value Unvested balance at December 31, 2023 328,752 $29.15 Forfeited (46,407) $29.15 Unvested balance at March 31, 2024 282,345 $29.15 As of March 31, 2024, the Company had $1.2 million of unrecognized stock-based compensation expense related to unvested PSUs expected to be recognized over a remaining weighted-average period of 0.29 years. 2020 Employee Stock Purchase Plan In June 2020, the Company adopted the Company's 2020 Employee Stock Purchase Plan (the “2020 ESPP”). The 2020 ESPP provides that the number of shares reserved and available for issuance will automatically increase on January 1 of each calendar year, beginning January 1, 2021, by the least of (1) 1.0% of the total number of shares of common stock outstanding on December 31 of the preceding calendar year, (2) 700,000 shares or (3) such lesser amount as determined by the administrator of the 2020 ESPP, which is the compensation committee of the board of directors of the Company. Under the 2020 ESPP, eligible employees may purchase shares of our common stock through payroll deductions that cannot exceed 15% of each employee’s salary. The 2020 ESPP provides for a six-month offering period. At the end of the purchase period, eligible employees are permitted to purchase shares of common stock at the lower of 85% of the fair market value at the beginning of the offering period or 85% of the fair market value at the end of the purchase period, subject to tax limitations on the total value of the purchase. The 2020 ESPP is considered a compensatory plan, and the Company recorded $0.1 million and $0.2 million in stock-based compensation expense for the three months ended March 31, 2024 and 2023, respectively. During the three months ended March 31, 2024, 68,882 shares of common stock were issued under the 2020 ESPP with 1,336,085 shares remaining available for issuance under the 2020 ESPP. The Company used Black-Scholes option pricing model to estimate stock-based compensation expense for the 2020 ESPP with the following assumptions: Three months ended March 31, 2024 2023 Risk-free interest rate 5.27% 5.20% Expected term of options (in years) 0.50 0.50 Expected stock price volatility 63.92% 69.15% Expected dividends — — Stock-Based Compensation Expense The following table presents the components and classification of stock-based compensation expense for the Company’s stock-based awards for the three months ended March 31, 2024 and 2023 (in thousands): Three Months Ended 2024 2023 Stock options and ESPP $ 6,358 $ 4,803 Restricted stock units 3,246 2,606 Performance-based restricted stock units 62 4,514 Total stock-based compensation expense $ 9,666 $ 11,923 Research and development expenses $ 3,070 $ 4,848 General and administrative expenses $ 6,596 $ 7,075

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2024
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes For the three months ended March 31, 2024 and 2023, the Company did not record an income tax provision. The Company will continue to maintain a 100% valuation allowance on total deferred tax assets. The Company believes it is more likely than not that the related deferred tax asset will not be realized. As a result, the Company’s effective tax rate will remain at 0% because there are no estimated or discrete items that would impact the tax provision.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Purchase Commitments The Company has contractual arrangements with research and development organizations and suppliers; however, these contracts are generally cancellable on 30 days’ notice and the obligations under these contracts are largely based on services performed.

Leases

Leases	3 Months Ended
	Mar. 31, 2024
Leases [Abstract]
Leases	Leases New Operating Lease On September 28, 2023, the Company entered into a lease agreement with HCP BTC, LLC, a Delaware limited liability company (“the Landlord”) for a premise consisting of approximately 100,904 square feet of office and laboratory space located at Oyster Point Blvd, South San Francisco, California (the “Oyster Point Lease”), which the Company intends to use as single unified Company headquarters. The lease term of approximately seven years will start upon the Landlord’s substantial completion of tenant improvements, and may be extended for a period of eight years at then prevailing market rates for a comparable property. Future lease payments are approximately $43.7 million which represent the non-cancellable periods of the lease. We excluded extension options that are not reasonably certain to be exercised from our lease terms. Our lease payments consist primarily of fixed rental payments for the right to use the underlying leased assets over the lease term. Additionally, the Company provided a letter of credit to the Landlord in the amount of $1.4 million in connection with the Oyster Point Lease, which has been recognized as restricted cash as at March 31, 2024. Though the Oyster Point Lease will be accounted for as a single contract, the office space was occupied in March 2024 while the laboratory space is expected to be occupied in the second quarter of 2024. Accordingly, the Company measured and allocated consideration to each lease component as of March 31, 2024. The Company has recognized a right-of-use asset ("ROU") or aggregate lease liability of $23.7 million as at March 31, 2024, discounted at 9.23%, the Company's estimated incremental borrowing rate during the three months ended March 31, 2024. The undiscounted future non-cancellable lease payments of the Company's operating lease liability as of March 31, 2024 were as follows (in thousands): Operating Lease 2024 (remainder of the year) $ 2,037 2025 2,849 2026 3,537 2027 4,735 2028 5,996 2029 and thereafter 16,718 Total undiscounted lease payments $ 35,872 Less: Present value discount (11,219) Total operating lease liabilities current $ 773 Total operating lease liabilities non-current $ 23,880 The weighted-average remaining lease terms and discount rates related to the Company's operating leases were as follows: As of March 31, 2024 As of March 31, 2023 Weighted-average remaining lease term (in years) 6.9 2.1 Weighted-average discount rate 9.4% 8.2%

Defined Contribution Plan

Defined Contribution Plan	3 Months Ended
	Mar. 31, 2024
Retirement Benefits [Abstract]
Defined Contribution Plan	Defined Contribution Plan The Company sponsors a defined contribution plan under Section 401(k) of the Internal Revenue Code covering substantially all full-time U.S. employees. Employee contributions are voluntary and are determined on an individual basis subject to the maximum allowable under federal tax regulations. The Company made contributions to the plan of $0.3 million for each of the three months ended March 31, 2024 and 2023, respectively.

Net Loss Per Share Attributable

Net Loss Per Share Attributable to Common Stockholders	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Net Loss Per Share Attributable to Common Stockholders	Net Loss Per Share Attributable to Common Stockholders The following outstanding shares of potentially dilutive securities were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented, because including them would have been antidilutive: Three Months Ended March 31, 2024 2023 Options to purchase common stock 7,659,860 6,380,591 Restricted stock units 1,201,724 1,168,536 Performance-based restricted stock units* — — Total 8,861,584 7,549,127 *No unvested performance-based restricted stock units are included above as none of the contingently issuable shares would be issued assuming the end of our reporting period was the end of the relevant PSU award contingency period

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (46,955)	$ (37,548)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Mar. 31, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited interim condensed financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and follow the requirements of the Securities and Exchange Commission (“SEC”), for interim financial reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP have been condensed or omitted, and accordingly the unaudited interim condensed financial statements do not include all of the information and notes required by U.S. GAAP for complete financial statements. These unaudited interim condensed financial statements have been prepared on the same basis as our annual financial statements and, in the opinion of management, reflect all adjustments (consisting only of normal recurring adjustments) that are necessary for a fair presentation of the Company's financial information. The results of operations for the three months ended March 31, 2024 are not necessarily indicative of the results to be expected for the year ending December 31, 2024 or for any other interim period or for any other future year.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, and expenses as well as the disclosure of contingent assets and liabilities as of and during the reporting period. The Company bases its estimates and assumptions on historical experience when available and on various factors that it believes to be reasonable under the circumstances. Significant estimates and assumptions reflected in these financial statements include, but are not limited to, stock-based compensation expense, operating lease right-of-use (“ROU”) assets and liabilities, accruals and prepayments for research and development costs, income taxes and uncertain tax positions. The Company assesses estimates on an ongoing basis, however, actual results could materially differ from those estimates.
Recently Announced Accounting Pronouncements	Recently Announced Accounting Pronouncements In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which requires public entities to disclose information about their reportable segments’ significant expenses on an interim and annual basis. ASU 2023-07 is effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. Entities must adopt the changes to the segment reporting guidance on a retrospective basis, and early adoption is permitted. The Company is currently evaluating the impact of this standard on its disclosures and will adopt the ASU for its 2024 10-K. In December 2023, the FASB issued ASU 2023-09 "Income Taxes (Topic 740): Improvements to Income Tax Disclosures", which expands disclosures in an entity’s income tax rate reconciliation table and regarding cash taxes paid both in the U.S. and foreign jurisdictions. The Company is currently evaluating the impact of this standard on its disclosures and will adopt the ASU for its 2025 10-K.

Financial Instruments (Tables)

Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Schedule of Money Market Funds, U.S. Government Agency Securities and Corporate Debt Securities by Significant Investment Category	The following tables show the Company’s Money Market Funds, U.S. Treasury securities, U.S. government agency securities and corporate debt securities by significant investment category as of March 31, 2024 and December 31, 2023 (in thousands): As of March 31, 2024 As of December 31, 2023 Adjusted Unrealized Unrealized Market Adjusted Unrealized Unrealized Market Money Market Funds Level 1 $ 66,387 $ — $ — $ 66,387 $ 57,241 $ — $ — $ 57,241 U.S. Treasury securities Level 2 23,493 — (17) 23,476 27,250 46 (8) 27,288 U.S. Government agency securities Level 2 122,121 107 (234) 121,994 133,655 563 (132) 134,086 Corporate debt securities Level 2 239,912 43 (389) 239,566 269,761 213 (337) 269,637 Total financial assets $ 451,913 $ 150 $ (640) $ 451,423 $ 487,907 $ 822 $ (477) $ 488,252 As of March 31, 2024 As of December 31, 2023 Adjusted Unrealized Unrealized Market Adjusted Unrealized Unrealized Market Classified as: Cash equivalents $ 83,336 $ — $ (5) $ 83,331 $ 57,241 $ — $ — $ 57,241 Short-term investments 368,577 150 (635) 368,092 430,666 822 (477) 431,011 Total $ 451,913 $ 150 $ (640) $ 451,423 $ 487,907 $ 822 $ (477) $ 488,252

Property and Equipment, net (Ta

Property and Equipment, net (Tables)	3 Months Ended
	Mar. 31, 2024
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment, Net	Property and equipment, net consisted of the following (in thousands): As of March 31, 2024 As of December 31, 2023 Laboratory equipment 10,423 10,410 Leasehold improvements 1,964 1,663 Furniture and fixtures 1,728 — Computer equipment and software 620 124 Construction-in-progress 65 52 Total property and equipment, gross 14,800 12,249 Less: Accumulated depreciation (9,195) (8,682) Total property and equipment, net 5,605 3,567

Prepaid Expenses and Other Cu_2

Prepaid Expenses and Other Current Assets (Tables)	3 Months Ended
	Mar. 31, 2024
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Schedule of Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consisted of the following (in thousands): As of March 31, 2024 As of December 31, 2023 Prepaid research and development 2,540 3,403 Prepaid insurance 769 1,131 Prepaid licenses 1,274 2,454 Interest receivable 2,315 2,997 Other 611 1,272 Total prepaid expenses and other current assets 7,509 11,257

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	3 Months Ended
	Mar. 31, 2024
Accrued Liabilities and Other Liabilities [Abstract]
Schedule of Accrued Liabilities	Accrued liabilities consisted of the following (in thousands): As of March 31, 2024 As of December 31, 2023 Accrued compensation and benefits 4,541 $ 9,042 Other accrued liabilities 1,327 1,177 Total accrued liabilities $ 5,868 $ 10,219

Long-term Debt (Tables)

Long-term Debt (Tables)	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
Schedule of Maturities of Long-Term Debt	Future maturities of debt as of March 31, 2024 are as follows (in thousands): As of March 31, 2024 2028 $ 20,000 2029 10,000 Thereafter — Total payments 30,000 Less: unamortized debt issuance costs (191) Accretion of final payment 193 Total $ 30,002

Common Stock (Tables)

Common Stock (Tables)	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
Schedule of Shares Reserved for Future Issuance	Shares reserved for future issuance As of March 31, As of December 31, 2023 Outstanding stock option awards 7,659,860 6,953,487 Vesting of RSUs 1,201,724 874,748 Vesting of PSUs* 282,345 328,752 Shares of common stock available for future grants under the 2020 Stock Option and Incentive Plan 4,562,694 2,882,239 Shares of common stock available for future issuance under the 2020 Employee Stock Purchase Plan 1,336,085 805,756 Shares of common stock available for future issuance under the 2022 Inducement Plan 700,000 700,000 Total shares reserved for future issuance 15,742,708 12,544,982 *PSUs granted and outstanding based on target level of achievement of 100%.

Equity Incentive Plans and St_2

Equity Incentive Plans and Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
Schedule of Black-Scholes Option Pricing Model to Estimate Stock-based Compensation Expense for Stock Option Awards	The Company used Black-Scholes option pricing model to estimate stock-based compensation expense for stock option awards with the following assumptions: Three months ended March 31, 2024 2023 Expected volatility 85.28% - 86.42% 80.97% - 81.41% Risk-free interest rate 4.04% - 4.28% 3.42% - 4.18% Expected dividend — — Expected term (in years) 5.99 - 6.06 5.77 - 6.08 Underlying common stock fair value $15.19 - $17.44 $21.94 - $34.65
Schedule of Option Activity Under the 2015 Plan and 2020 Plan	A summary of option activity under the 2015 Plan and the 2020 Plan is as follows: Number Weighted- Weighted- Aggregate Outstanding as of December 31, 2023 6,953,487 $ 17.95 7.70 $ 32,646 Granted 1,338,465 $ 17.29 Exercised (118,573) $ 8.01 Forfeited (513,519) $ 16.87 Outstanding as of March 31, 2024 7,659,860 $ 18.06 7.83 $ 18,505 Exercisable as of March 31, 2024 7,659,860 $ 18.06 7.83 $ 18,505 Vested and expected to vest as of March 31, 2024 3,651,242 $ 15.84 6.70 $ 15,456
Schedule of Restricted Stock Activity	The following table sets forth the outstanding RSUs and related activity for the three months ended March 31, 2024 Restricted Stock Units Weighted Average Grant Date Fair Value Unvested and outstanding as of December 31, 2023 874,748 $ 29.85 Granted 594,336 $ 17.44 Released (210,085) $ 34.65 Forfeited (57,275) $ 27.88 Unvested and outstanding as of March 31, 2024 1,201,724 $ 22.97
Schedule of Share-Based Payment Award, Equity Instruments Other Than Options, Valuation Assumptions	The fair value of the TSR PSUs were derived from a Monte Carlo simulation model that used the following key assumptions: Valuation date share price $ 17.57 Award term (years) 1.92 Volatility 70.62 % Correlation coefficient 0.3508 Average peer group volatility 79.69 % Average peer group correlation coefficient 0.4397 Risk-free interest rate 2.84 %
Share-Based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity	The following table sets forth the outstanding PSUs associated with TSR goal and related activity during the three months ended March 31, 2024: Performance Stock Units Weighted Average Grant Date Fair Value Unvested balance at December 31, 2023 328,752 $29.15 Forfeited (46,407) $29.15 Unvested balance at March 31, 2024 282,345 $29.15
Schedule of Black-Scholes Option Pricing Model to Estimate Stock-based Compensation Expense for 2020 Employee Stock Purchase Plan	The Company used Black-Scholes option pricing model to estimate stock-based compensation expense for the 2020 ESPP with the following assumptions: Three months ended March 31, 2024 2023 Risk-free interest rate 5.27% 5.20% Expected term of options (in years) 0.50 0.50 Expected stock price volatility 63.92% 69.15% Expected dividends — —
Schedule of Classification of Stock-based Compensation Expense	The following table presents the components and classification of stock-based compensation expense for the Company’s stock-based awards for the three months ended March 31, 2024 and 2023 (in thousands): Three Months Ended 2024 2023 Stock options and ESPP $ 6,358 $ 4,803 Restricted stock units 3,246 2,606 Performance-based restricted stock units 62 4,514 Total stock-based compensation expense $ 9,666 $ 11,923 Research and development expenses $ 3,070 $ 4,848 General and administrative expenses $ 6,596 $ 7,075

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2024
Leases [Abstract]
Schedule of Operating Lease Liability	The undiscounted future non-cancellable lease payments of the Company's operating lease liability as of March 31, 2024 were as follows (in thousands): Operating Lease 2024 (remainder of the year) $ 2,037 2025 2,849 2026 3,537 2027 4,735 2028 5,996 2029 and thereafter 16,718 Total undiscounted lease payments $ 35,872 Less: Present value discount (11,219) Total operating lease liabilities current $ 773 Total operating lease liabilities non-current $ 23,880
Schedule of Weighted-average Remaining Lease Terms and Discount Rates	The weighted-average remaining lease terms and discount rates related to the Company's operating leases were as follows: As of March 31, 2024 As of March 31, 2023 Weighted-average remaining lease term (in years) 6.9 2.1 Weighted-average discount rate 9.4% 8.2%
Schedule of Operating and Variable Lease Cost	Lease expenses for each of the three months ended March 31, 2024 and 2023 are as follows (in thousands): As of March 31, 2024 As of March 31, 2023 Operating lease costs $ 972 $ 770 Other variable costs 165 243 Total expense $ 1,137 $ 1,013

Net Loss Per Share Attributab_2

Net Loss Per Share Attributable to Common Stockholders (Tables)	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Schedule of Potentially Dilutive Securities Excluded from Computation of Diluted Net Loss Per Share	The following outstanding shares of potentially dilutive securities were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented, because including them would have been antidilutive: Three Months Ended March 31, 2024 2023 Options to purchase common stock 7,659,860 6,380,591 Restricted stock units 1,201,724 1,168,536 Performance-based restricted stock units* — — Total 8,861,584 7,549,127 *No unvested performance-based restricted stock units are included above as none of the contingently issuable shares would be issued assuming the end of our reporting period was the end of the relevant PSU award contingency period

Organization and Description _2

Organization and Description of Business (Details) $ / shares in Units, $ in Millions	1 Months Ended
	Jan. 31, 2023 USD ($) $ / shares shares
Public Offering
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Initial public offering, shares issued (in shares)	9,583,334
Private Placement | Underwriters
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Initial public offering, shares issued (in shares)	1,250,000
Public Offering And Private Placement
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Share price of shares issued in initial public offering (USD per share) | $ / shares	$ 30
Proceeds from the initial public offering | $	$ 269.8

Financial Instruments - Narrati

Financial Instruments - Narrative (Details) - USD ($)	Mar. 31, 2024	Dec. 31, 2023
Fair Value, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities measured at fair value	$ 0	$ 0
Fair Value Measurements, Non-recurring Basis
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities measured at fair value	0	0
Assets measured at fair value	0	0
Fair Value, Inputs, Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities measured at fair value	0	0
Assets measured at fair value	$ 0	$ 0

Financial Instruments - Schedul

Financial Instruments - Schedule of Cash and Cash Equivalents, Money Market Funds and Short-term Investments by Significant Investment Category (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Adjusted Cost	$ 451,913	$ 487,907
Unrealized Gains	150	822
Unrealized Losses	(640)	(477)
Market Value	451,423	488,252
Short-term investments
Debt Securities, Available-for-sale [Line Items]
Adjusted Cost	368,577	430,666
Unrealized Gains	150	822
Unrealized Losses	(635)	(477)
Market Value	368,092	431,011
Cash Equivalents
Debt Securities, Available-for-sale [Line Items]
Adjusted Cost	83,336	57,241
Unrealized Gains	0	0
Unrealized Losses	(5)	0
Market Value	83,331	57,241
Level 1 | Money Market Funds
Debt Securities, Available-for-sale [Line Items]
Adjusted Cost	66,387	57,241
Unrealized Gains	0	0
Unrealized Losses	0	0
Market Value	66,387	57,241
Level 2 | U.S. Treasury securities
Debt Securities, Available-for-sale [Line Items]
Adjusted Cost	23,493	27,250
Unrealized Gains	0	46
Unrealized Losses	(17)	(8)
Market Value	23,476	27,288
Level 2 | U.S. Government agency securities
Debt Securities, Available-for-sale [Line Items]
Adjusted Cost	122,121	133,655
Unrealized Gains	107	563
Unrealized Losses	(234)	(132)
Market Value	121,994	134,086
Level 2 | Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Adjusted Cost	239,912	269,761
Unrealized Gains	43	213
Unrealized Losses	(389)	(337)
Market Value	$ 239,566	$ 269,637

Property and Equipment, net - S

Property and Equipment, net - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	$ 14,800	$ 12,249
Less: Accumulated depreciation	(9,195)	(8,682)
Total property and equipment, net	5,605	3,567	[1]
Laboratory equipment
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	10,423	10,410
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	1,964	1,663
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	1,728	0
Computer equipment and software
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	620	124
Construction-in-progress
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	$ 65	$ 52
[1] The condensed balance sheet as of December 31, 2023 has been derived from the audited financial statements as of that date .

Property and Equipment, net - N

Property and Equipment, net - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 513	$ 452

Prepaid Expenses and Other Cu_3

Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid research and development	$ 2,540	$ 3,403
Prepaid insurance	769	1,131
Prepaid licenses	1,274	2,454
Interest receivable	2,315	2,997
Other	611	1,272
Total prepaid expenses and other current assets	$ 7,509	$ 11,257	[1]
[1] The condensed balance sheet as of December 31, 2023 has been derived from the audited financial statements as of that date .

Accrued Liabilities (Details)

Accrued Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Accrued Liabilities and Other Liabilities [Abstract]
Accrued compensation and benefits	$ 4,541	$ 9,042
Other accrued liabilities	1,327	1,177
Total accrued liabilities	$ 5,868	$ 10,219

Long-term Debt - Narrative (Det

Long-term Debt - Narrative (Details) - USD ($)		1 Months Ended	3 Months Ended
	Mar. 11, 2024	Oct. 31, 2022	Mar. 31, 2024	Mar. 31, 2023	Jul. 01, 2029	Mar. 10, 2024	Dec. 31, 2023	May 31, 2022
Debt Instrument [Line Items]
Proceeds from term loan, net of issuance costs			$ 19,909,000	$ 0
Interest expense			445,000	311,000
Loan Agreement | Term Loan Facility
Debt Instrument [Line Items]
Term loan facility	$ 150,000,000	$ 100,000,000
Proceeds from term loan, net of issuance costs		$ 10,000,000
Line of credit, amount subject to lender's discretion	50,000,000
Line of credit facility, current borrowing capacity	$ 30,000,000
Line of credit						$ 10,000,000
Line of credit facility, remaining borrowing capacity			70,000,000
Outstanding amount threshold, maximum collateral requirement			$ 50,000,000
Debt instrument final payment, percentage of original principal amount drawn			5.50%
Interest rate in case of default	5%
Effective interest rate for the term loan			11.93%
Interest expense			$ (440,000)	$ 300,000
Loan Agreement | Term Loan Facility | Minimum
Debt Instrument [Line Items]
Stated percentage	3.50%
Stated interest rate plus variable rate floor			8.75%
Loan Agreement | Term Loan Facility | Debt Instrument, Stated Interest Rate
Debt Instrument [Line Items]
Variable rate			5.25%
Loan Agreement | Term Loan Facility | First Anniversary
Debt Instrument [Line Items]
Prepayment fee percentage	3%
Loan Agreement | Term Loan Facility | Second Anniversary
Debt Instrument [Line Items]
Prepayment fee percentage	2%
Loan Agreement | Term Loan Facility | Subsequent To Second Anniversary
Debt Instrument [Line Items]
Prepayment fee percentage	1%
Loan Agreement | Term Loan Facility | Forecast
Debt Instrument [Line Items]
Debt instrument final payment, percentage of original principal amount drawn					7.25%
Loan Agreement | Term Loan Facility | Debt Draw, Tranche Two
Debt Instrument [Line Items]
Amount undrawn							$ 65,000,000	$ 65,000,000

Long-term Debt - Schedule of Ma

Long-term Debt - Schedule of Maturities of Long-Term Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	[1]
Debt Disclosure [Abstract]
2028	$ 20,000
2029	10,000
Thereafter	0
Total payments	30,000
Less: unamortized debt issuance costs	(191)
Accretion of final payment	193
Total	$ 30,002	$ 10,054
[1] The condensed balance sheet as of December 31, 2023 has been derived from the audited financial statements as of that date .

Novartis Collaboration and Li_2

Novartis Collaboration and License Agreement (the "Novartis Agreement") (Details) - Novartis - Novartis Agreement $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2019 researchTarget
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenues | $	$ 0	$ 1.3
Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of integrin research targets | researchTarget			3

Preferred Stock (Details)

Preferred Stock (Details)	Mar. 31, 2024 class shares	Dec. 31, 2023 shares
Temporary Equity Disclosure [Abstract]
Number of classes of stock authorized | class	2
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares outstanding (in shares)	0	0

Common Stock - Narrative (Detai

Common Stock - Narrative (Details)	3 Months Ended
	Mar. 31, 2024 vote $ / shares shares	Dec. 31, 2023 $ / shares shares
Equity [Abstract]
Common stock, shares authorized (in shares) | shares	300,000,000	300,000,000
Common stock, par value (USD per share)	$ 0.0001	$ 0.0001
Common stock, voting rights, number of votes per share | vote	1
Dividends declared (USD per share)	$ 0
Dividends paid (USD per share)	$ 0

Common Stock - Schedule of Shar

Common Stock - Schedule of Shares Reserved for Future Issuance (Details) - shares	Mar. 31, 2024	Dec. 31, 2023
Class of Stock [Line Items]
Total shares reserved for future issuance (in shares)	15,742,708	12,544,982
Shares of common stock available for future grants under the 2020 Stock Option and Incentive Plan
Class of Stock [Line Items]
Total shares reserved for future issuance (in shares)	4,562,694	2,882,239
Shares of common stock available for future issuance under the 2020 Employee Stock Purchase Plan
Class of Stock [Line Items]
Total shares reserved for future issuance (in shares)	1,336,085	805,756
Shares of common stock available for future issuance under the 2022 Inducement Plan
Class of Stock [Line Items]
Total shares reserved for future issuance (in shares)	700,000	700,000
Outstanding stock option awards
Class of Stock [Line Items]
Total shares reserved for future issuance (in shares)	7,659,860	6,953,487
Vesting of RSUs
Class of Stock [Line Items]
Total shares reserved for future issuance (in shares)	1,201,724	874,748
Vesting of PSUs*
Class of Stock [Line Items]
Total shares reserved for future issuance (in shares)	282,345	328,752

Equity Incentive Plans and St_3

Equity Incentive Plans and Stock-Based Compensation - Equity Incentive Plan - Narrative (Details) - shares	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total shares reserved for future issuance (in shares)	15,742,708	12,544,982
2020 Stock Options and Incentive Plan and 2022 Inducement Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price as a percentage of estimated grant date fair value of shares	10%
Expiration period from date of grant	5 years
Shares of common stock available for future grants under the 2020 Stock Option and Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total shares reserved for future issuance (in shares)	4,562,694	2,882,239
Shares of common stock available for future issuance under the 2022 Inducement Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total shares reserved for future issuance (in shares)	700,000	700,000
Maximum | 2020 Stock Options and Incentive Plan and 2022 Inducement Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period in which options may be granted	10 years
Exercise price as a percentage of estimated grant date fair value of shares	110%
Maximum | Shares of common stock available for future grants under the 2020 Stock Option and Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of outstanding shares, shares added per year to plan	5%

Equity Incentive Plans and St_4

Equity Incentive Plans and Stock-Based Compensation - Incentive Stock Options and Nonqualified Stock Options - Narrative (Details) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($) $ / shares shares
2015 Equity and 2020 Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Expiration period from date of grant	10 years
2015 Equity and 2020 Incentive Plan | Incentive Stock Options and Nonqualified Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)	1,338,465
Unrecognized compensation cost | $	$ 53.9
Unrecognized compensation expense, weighted average period	2 years 9 months 18 days
Grant date fair value of stock option (in shares) | $ / shares	$ 17.29
Shares of common stock available for future grants under the 2020 Stock Option and Incentive Plan | Incentive Stock Options and Nonqualified Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)	1,338,465

Equity Incentive Plans and St_5

Equity Incentive Plans and Stock-Based Compensation - Schedule of Black-Scholes Option Pricing Model to Estimate Stock-based Compensation Expense for Stock Option Awards (Details) - Incentive Stock Options and Nonqualified Stock Options - 2015 Equity and 2020 Incentive Plan - $ / shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility, minimum	85.28%	80.97%
Expected volatility, maximum	86.42%	81.41%
Risk-free interest rate, minimum	4.04%	3.42%
Risk-free interest rate, maximum	4.28%	4.18%
Expected dividend	0%	0%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	5 years 11 months 26 days	5 years 9 months 7 days
Underlying common stock fair value (USD per share)	$ 15.19	$ 21.94
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 years 21 days	6 years 29 days
Underlying common stock fair value (USD per share)	$ 17.44	$ 34.65

Equity Incentive Plans and St_6

Equity Incentive Plans and Stock-Based Compensation - Schedule of Option Activity Under the 2015 Plan and 2020 Plan (Details) - Incentive Stock Options and Nonqualified Stock Options - 2015 Equity and 2020 Incentive Plan - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Number of Options
Outstanding, beginning balance (in shares)	6,953,487
Granted (in shares)	1,338,465
Exercised (in shares)	(118,573)
Forfeited (in shares)	(513,519)
Outstanding, ending balance (in shares)	7,659,860	6,953,487
Number of options, exercisable (in shares)	7,659,860
Number of options, vested and expected to vest (in shares)	3,651,242
Weighted- Average Exercise Price per Share
Outstanding, beginning balance (USD per share)	$ 17.95
Granted (USD per share)	17.29
Exercised (USD per share)	8.01
Forfeited (USD per share)	16.87
Outstanding, ending balance (USD per share)	18.06	$ 17.95
Weighted- average exercise price per share, exercisable (USD per share)	18.06
Weighted- average exercise price per share, vested and expected to vest (USD per share)	$ 15.84
Weighted- average remaining contractual term (in years), outstanding	7 years 9 months 29 days	7 years 8 months 12 days
Weighted- average remaining contractual term (in years), exercisable	7 years 9 months 29 days
Weighted- average remaining contractual term (in years), vested and expected to vest	6 years 8 months 12 days
Aggregate intrinsic value, outstanding balance	$ 18,505	$ 32,646
Aggregate intrinsic value, exercisable	18,505
Aggregate intrinsic value, vested and expected to vest	$ 15,456

Equity Incentive Plans and St_7

Equity Incentive Plans and Stock-Based Compensation - Restricted Stock Units - Narrative (Details) - Restricted stock units $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost	$ 22.9
Unrecognized compensation expense, weighted average period	2 years
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	2 years
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years

Equity Incentive Plans and St_8

Equity Incentive Plans and Stock-Based Compensation - Schedule of Restricted Stock Activity (Details) - Restricted stock units	3 Months Ended
	Mar. 31, 2024 $ / shares shares
Performance Stock Units
Outstanding and unvested, beginning balance (in shares) | shares	874,748
Granted (in shares) | shares	594,336
Released (in shares) | shares	(210,085)
Forfeited (in shares) | shares	(57,275)
Outstanding and unvested, ending balance (in shares) | shares	1,201,724
Weighted Average Grant Date Fair Value
Unvested and outstanding, beginning balance (USD per share) | $ / shares	$ 29.85
Granted (USD per share) | $ / shares	17.44
Released (USD per share) | $ / shares	34.65
Forfeited (USD per share) | $ / shares	27.88
Unvested and outstanding, ending balance (USD per share) | $ / shares	$ 22.97

Equity Incentive Plans and St_9

Equity Incentive Plans and Stock-Based Compensation - Performance-Based Restricted Stock Units - Narrative (Details) - Performance-based restricted stock units $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost	$ 1.2
Unrecognized compensation expense, weighted average period	3 months 14 days
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting rights, percentage	0%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting rights, percentage	200%

Equity Incentive Plans and S_10

Equity Incentive Plans and Stock-Based Compensation - Schedule of TSR PSU Valuation Assumptions (Details) - Performance-Based Restricted Stock Units, TSR Goal	3 Months Ended
	Mar. 31, 2024 $ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Valuation date share price (in dollars per share)	$ 17.57
Expected term (in years)	1 year 11 months 1 day
Volatility	70.62%
Correlation coefficient	0.3508
Average peer group volatility	79.69%
Average peer group correlation coefficient	0.4397
Risk-free interest rate	2.84%

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Outstanding PSUs Associated with the TSR goal (Details) - Performance-Based Restricted Stock Units, TSR Goal - $ / shares	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Performance Stock Units
Outstanding and unvested, beginning balance (in shares)	328,752
Forfeited (in shares)	(46,407)
Outstanding and unvested, ending balance (in shares)	282,345
Weighted Average Grant Date Fair Value
Weighted-average grant date fair value, outstanding and unvested (USD per share)	$ 29.15	$ 29.15
Forfeited (USD per share)	$ 29.15

Equity Incentive Plans and S_11

Equity Incentive Plans and Stock-Based Compensation - 2020 Employee Stock Purchase Plan - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Jun. 30, 2020	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total shares reserved for future issuance (in shares)		15,742,708		12,544,982
Total stock-based compensation expense		$ 9,666	$ 11,923
2020 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee stock purchase plan, description	The 2020 ESPP provides that the number of shares reserved and available for issuance will automatically increase on January 1 of each calendar year, beginning January 1, 2021, by the least of (1) 1.0% of the total number of shares of common stock outstanding on December 31 of the preceding calendar year, (2) 700,000 shares or (3) such lesser amount as determined by the administrator of the 2020 ESPP, which is the compensation committee of the board of directors of the Company.
Common stock shares outstanding percentage	1%
Total shares reserved for future issuance (in shares)	700,000	1,336,085
Percentage of payroll deductions	15%
Employee stock purchase plan offering period	6 months
Common stock fair market value percentage	85%
Total stock-based compensation expense		$ 100	$ 200
Number of common stock issued (in shares)		68,882

Equity Incentive Plans and S_12

Equity Incentive Plans and Stock-Based Compensation - 2020 Employee Stock Purchase Plan - Schedule of Black-Scholes Option Pricing Model to Estimate Stock-based Compensation Expense for 2020 Employee Stock Purchase Plan (Details) - 2020 Employee Stock Purchase Plan	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	5.27%	5.20%
Expected term of options (in years)	6 months	6 months
Expected stock price volatility	63.92%	69.15%
Expected dividend	0%	0%

Equity Incentive Plans and S_13

Equity Incentive Plans and Stock-Based Compensation - Schedule of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 9,666	$ 11,923
Research and development expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	3,070	4,848
General and administrative expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	6,596	7,075
Stock options and ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	6,358	4,803
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	3,246	2,606
Performance-based restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 62	$ 4,514

Income Taxes (Details)

Income Taxes (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Tax Disclosure [Abstract]
Income tax provision	$ 0	$ 0
Valuation allowance as a percentage on total deferred tax assets	100%
Effective tax rate	0%

Commitments and Contingencies (

Commitments and Contingencies (Details)	3 Months Ended
	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Contractual arrangements cancellation period	30 days

Leases - Narrative (Details)

Leases - Narrative (Details) $ in Thousands	Sep. 28, 2023 USD ($) ft²	Mar. 31, 2024 USD ($)	Mar. 31, 2023
Lessee, Lease, Description [Line Items]
Future lease payments		$ 35,872
Weighted-average discount rate		9.40%	8.20%
California
Lessee, Lease, Description [Line Items]
Leased premises under non cancelable operating lease | ft²	100,904,000
Lease term	7 years
Lease term extension period	8 years
Future lease payments		$ 43,700
Operating lease, liability		$ 23,700
Weighted-average discount rate		9.23%
California | Letter of Credit | Pliant Therapeutics | Landlord
Lessee, Lease, Description [Line Items]
Line of credit	$ 1,400

Leases - Schedule of Operating

Leases - Schedule of Operating Lease Liability (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	[1]
Lessee, Operating Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract]
2024 (remainder of the year)	$ 2,037
2025	2,849
2026	3,537
2027	4,735
2028	5,996
2029 and thereafter	16,718
Total undiscounted lease payments	35,872
Less: Present value discount	(11,219)
Total operating lease liabilities current	773	$ 1,318
Total operating lease liabilities non-current	$ 23,880	$ 0
[1] The condensed balance sheet as of December 31, 2023 has been derived from the audited financial statements as of that date .

Leases - Schedule of Weighted-a

Leases - Schedule of Weighted-average Remaining Lease Terms and Discount Rates (Details)	Mar. 31, 2024	Mar. 31, 2023
Leases [Abstract]
Weighted-average remaining lease term (in years)	6 years 10 months 24 days	2 years 1 month 6 days
Weighted-average discount rate	9.40%	8.20%

Leases - Schedule of Operatin_2

Leases - Schedule of Operating and Variable Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Leases [Abstract]
Operating lease costs	$ 972	$ 770
Other variable costs	165	243
Total expense	$ 1,137	$ 1,013

Defined Contribution Plan (Deta

Defined Contribution Plan (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Retirement Benefits [Abstract]
Payment made under defined contribution plan	$ 0.3	$ 0.3

Net Loss Per Share Attributab_3

Net Loss Per Share Attributable to Common Stockholders - Schedule of Potentially Dilutive Securities Excluded from Computation of Diluted Net Loss Per Share (Details) - shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	8,861,584	7,549,127
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	7,659,860	6,380,591
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	1,201,724	1,168,536
Performance-based restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	0	0