Kezar Life Sciences (KZR) 10-K 14 Mar 23 2022 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Mar. 10, 2023	Jun. 30, 2022
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY
Trading Symbol	KZR
Entity Registrant Name	Kezar Life Sciences, Inc.
Entity Central Index Key	0001645666
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		70,803,759
Entity Public Float			$ 551
Entity Interactive Data Current	Yes
Entity File Number	001-38542
Entity Tax Identification Number	47-3366145
Entity Address, Address Line One	4000 Shoreline Court
Entity Address, Address Line Two	Suite 300
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	822-5600
Document Annual Report	true
Document Transition Report	false
ICFR Auditor Attestation Flag	false
Title of 12(b) Security	Common Stock, $0.001 par value
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Portions of the definitive proxy statement for the 2023 Annual Meeting of Stockholders of the registrant, or the Proxy Statement, are incorporated by reference into Part III of this Annual Report on Form 10-K. The Proxy Statement will be filed with the Securities and Exchange Commission within 120 days of the registrant’s fiscal year ended December 31, 2022.
Auditor Name	KPMG LLP
Auditor Location	San Francisco, California
Auditor Firm ID	185

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 40,456	$ 62,882
Marketable securities	236,105	145,473
Prepaid expenses	8,241	2,570
Other current assets	920	729
Total current assets	285,722	211,654
Property and equipment, net	3,431	3,283
Operating lease right-of-use asset	9,741	2,714
Other assets	674	282
Total assets	299,568	217,933
Current liabilities:
Accounts payable	2,479	2,028
Accrued liabilities	5,953	4,985
Operating lease liabilities, current	2,565	1,199
Total current liabilities	10,997	8,212
Operating lease liabilities, noncurrent	8,865	3,223
Debt, noncurrent	9,834	9,622
Total liabilities	29,696	21,057
Stockholders' equity:
Common stock, $0.001 par value, 125,000,000 shares authorized as of December 31, 2022 and 2021; 68,493,429 and 56,259,747 shares issued and outstanding as of December 31, 2022 and 2021, respectively	68	56
Preferred stock, $0.001 par value, 10,000,000 shares authorized, zero shares issued and outstanding as of December 31, 2022 and 2021	0	0
Additional paid-in capital	519,620	377,765
Accumulated other comprehensive loss	(923)	(291)
Accumulated deficit	(248,893)	(180,654)
Total stockholders' equity	269,872	196,876
Total liabilities and stockholders' equity	$ 299,568	$ 217,933

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	125,000,000	125,000,000
Common stock, shares issued	68,493,429	56,259,747
Common stock, shares outstanding	68,493,429	56,259,747
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating expenses:
Research and development	$ 51,009	$ 38,935	$ 30,981
General and administrative	20,153	15,724	11,969
Total operating expenses	71,162	54,659	42,950
Loss from operations	(71,162)	(54,659)	(42,950)
Interest income	4,108	188	1,208
Interest expense	(1,185)	(159)	0
Net loss	$ (68,239)	$ (54,630)	$ (41,742)
Net loss per common share, Basic	$ (1.01)	$ (1.04)	$ (0.95)
Net loss per common share, Diluted	$ (1.01)	$ (1.04)	$ (0.95)
Weighted-average shares used to compute net loss per common share, basic	67,368,935	52,759,335	44,004,190
Weighted-average shares used to compute net loss per common share, diluted	67,368,935	52,759,335	44,004,190

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Comprehensive Income [Abstract]
Net loss	$ (68,239)	$ (54,630)	$ (41,742)
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustments	(49)	(50)	82
Net unrealized loss on marketable securities	(583)	(104)	(23)
Total other comprehensive (loss) income, net of tax	(632)	(154)	59
Comprehensive loss	$ (68,871)	$ (54,784)	$ (41,683)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	ATM Agreement	Common Stock	Common Stock ATM Agreement	Additional Paid-in Capital	Additional Paid-in Capital ATM Agreement	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balance at Dec. 31, 2019	$ 78,046		$ 19		$ 162,505		$ (196)	$ (84,282)
Balance, shares at Dec. 31, 2019			19,208,077
Issuance of common stock and pre-funded warrants through underwritten offerings, net of offering costs	99,161		$ 27		99,134
Issuance of common stock and pre-funded warrants through underwritten offerings, net of offering costs, shares			26,984,001
Issuance of common stock under employee stock incentive plans	470				470
Issuance of common stock under employee stock incentive plans, shares			167,665
Vesting related to shares of common stock issued pursuant to early exercises	41				41
Stock-based compensation expense	4,943				4,943
Other comprehensive income	59						59
Net loss	(41,742)							(41,742)
Balance at Dec. 31, 2020	$ 140,978		$ 46		267,093		(137)	(126,024)
Balance, shares at Dec. 31, 2020			46,359,743
Issuance of common stock net of offering costs		$ 100,995		$ 9		$ 100,986
Issuance of common stock net of offering costs, shares	9,352,359			9,352,359
Issuance of common stock under employee stock incentive plans	$ 2,070		$ 1		2,069
Issuance of common stock under employee stock incentive plans, shares			547,645
Vesting related to shares of common stock issued pursuant to early exercises	21				21
Stock-based compensation expense	7,596				7,596
Other comprehensive income	(154)						(154)
Net loss	(54,630)							(54,630)
Balance at Dec. 31, 2021	$ 196,876		$ 56		377,765		(291)	(180,654)
Balance, shares at Dec. 31, 2021			56,259,747
Issuance of common stock net of offering costs		$ 126,542		$ 12		$ 126,530
Issuance of common stock net of offering costs, shares	11,911,699			11,911,699
Issuance of common stock under employee stock incentive plans	$ 1,319				1,319
Issuance of common stock under employee stock incentive plans, shares			321,983
Stock-based compensation expense	14,006				14,006
Other comprehensive income	(632)						(632)
Net loss	(68,239)							(68,239)
Balance at Dec. 31, 2022	$ 269,872		$ 68		$ 519,620		$ (923)	$ (248,893)
Balance, shares at Dec. 31, 2022			68,493,429

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Pre-funded Warrants
Issuance of common stock through underwritten offerings, offering costs			$ 6,748
ATM Agreement
Issuance of common stock through underwritten offerings, offering costs	$ 3,913	$ 3,123

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net loss	$ (68,239)	$ (54,630)	$ (41,742)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,023	1,510	1,544
Stock-based compensation	14,006	7,596	4,943
Amortization of premiums and discounts on marketable securities	(1,401)	1,770	317
Amortization of debt discount and issuance costs and other non-cash interest	212	91	0
Loss on disposal of property and equipment	12	0	0
Changes in operating assets and liabilities
Prepaid expenses and other current assets	(5,787)	1,051	(1,424)
Other assets	(392)	0	0
Accounts payable and accrued liabilities	1,814	1,217	313
Operating lease asset and liabilities	(94)	(1,042)	(900)
Net cash used in operating activities	(58,846)	(42,437)	(36,949)
Cash flows from investing activities:
Purchases of property and equipment	(1,578)	(316)	(194)
Purchases of marketable securities	(332,203)	(156,378)	(225,728)
Maturities of marketable securities	242,389	128,250	169,424
Net cash used in investing activities	(91,392)	(28,444)	(56,498)
Cash flows from financing activities:
Proceeds from issuance of common stock under at-the-market offerings, net of issuance costs	126,542	100,970	0
Proceeds from long-term debt, net of debt discount and issuance costs of $469	0	9,531	0
Proceeds from sale of common stock and pre-funded warrants in public offerings, net of offering costs	0	0	99,186
Proceeds from issuance of common stock under employee stock incentive plans	1,319	2,084	456
Net cash provided by financing activities	127,861	112,585	99,642
Effect of exchange rate changes on cash and cash equivalents	(49)	(50)	82
Net (decrease) increase in cash and cash equivalents	(22,426)	41,654	6,277
Cash and cash equivalents at the beginning of period	62,882	21,228	14,951
Cash and cash equivalents at the end of period	40,456	62,882	21,228
Supplemental disclosures of noncash investing and financing information:
Reclassification of employee stock liability to equity upon vesting	0	21	41
Purchase of property and equipment in accounts payable	47	442	0
Unpaid offering costs in accrued liabilities	0	0	25
Supplemental disclosures
Cash paid for interest	$ 973	$ 69	$ 0

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)
Statement of Cash Flows [Abstract]
Debt discount and issuance costs	$ 469

Organization and Description of

Organization and Description of the Business	12 Months Ended
	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of the Business	1. Organization and Description of the Business Description of Business Kezar Life Sciences, Inc. (the “Company”) was incorporated in Delaware on February 19, 2015, and commenced operations in June 2015. The Company is a clinical-stage biotechnology company, discovering and developing novel small molecule therapeutics to treat unmet needs in immune-mediated diseases and cancer. The Company’s principal operations are in South San Francisco, California, and it operates in one segment. Liquidity Since commencing operations in mid-2015, substantially all of the Company’s efforts have been focused on research, development and the advancement of the Company’s lead product candidates, zetomipzomib and KZR-261. The Company’s ultimate success depends on the outcome of the ongoing research and development activities. The Company has not yet generated product sales and as a result has experienced operating losses since inception and had an accumulated deficit of $ 248.9 million as of December 31, 2022. The Company expects to incur additional losses in the future to conduct research and development and will need to raise additional capital to fully implement management’s business plan. The Company intends to raise such capital through the issuance of additional equity and potentially through borrowings, strategic alliances with partner companies and other licensing transactions. However, if such financing is not available at adequate levels, the Company may need to reevaluate its operating plans. Management believes that its cash, cash equivalents and marketable securities as of December 31, 2022 will be sufficient to fund the Company’s cash requirements for at least 12 months following the issuance of these financial statements. In 2022, the Company sold an aggregate of 11,911,699 shares of its common stock at a weighted average purchase price of $ 10.95 per share pursuant to the Company's a t-the-market offering program for net proceeds of approximately $ 126.5 million after deducting $ 3.9 million in commissions paid. In 2021, the Company sold an aggregate of 9,352,359 shares of its common stock at a weighted average purchase price of $ 11.13 per share pursuant to the Company's a t-the-market offering program for net proceeds of approximately $ 101.0 million after deducting $ 3.1 million in commissions paid. In November 2021, the Company entered into a loan and security agreement (the “Loan Agreement”) with Oxford Finance LLC (“Oxford Finance”), which provided the Company up to $ 50.0 million in borrowing capacity across five potential tranches. The initial tranche of $ 10.0 million was funded at the closing of the Loan Agreement. On June 11, 2020, the Company completed an underwritten public offering of 7,590,909 shares of its common stock and, to certain investors in lieu thereof, pre-funded warrants to purchase 909,091 shares of its common stock at an exercise price of $ 0.001 per share (the “June Offering”). The public offering price of the Company’s common stock was $ 5.50 per share and the public offering price of each pre-funded warrant was $ 5.499 per underlying share. In July 2020, the underwriters exercised an option to purchase an additional 427,707 shares of common stock. The net proceeds from the June Offering were approximately $ 45.8 million, after deducting underwriting discounts and commissions and other offering expenses paid by the Company. The Company’s existing stockholder, Equal Talent Investments Limited, and one of the Company’s directors purchased an aggregate of approximately $ 8.5 million of common stock in the June Offering. On February 4, 2020, the Company completed an underwritten public offering of 18,965,385 shares of its common stock, which includes the full exercise of the underwriters’ option to purchase additional shares of common stock, and, to certain investors in lieu thereof, pre-funded warrants to purchase 2,884,615 shares of its common stock at an exercise price of $ 0.001 per share (the “February Offering”). The public offering price of the Company’s common stock was $ 2.60 per share and the public offering price of each pre-funded warrant was $ 2.599 per underlying share. The net proceeds from the February Offering were approximately $ 53.4 million, after deducting underwriting discounts and commissions and other offering expenses paid by the Company. The Company’s existing stockholder, Morningside Ventures Investments Ltd, and certain of the Company’s officers and directors purchased an aggregate of approximately $ 10.4 million of common stock in the February Offering.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation and Consolidation The consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) and include the Company’s accounts and those of its wholly owned Australian subsidiary, Kezar Life Sciences Australia Pty Ltd, which is a proprietary company limited by shares. All intercompany balances and transactions have been eliminated upon consolidation. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Significant items subject to such estimates and assumptions include the valuation of marketable securities, stock-based compensation, and accrued research and development costs. Management bases its estimates on historical experience and on various other market-specific relevant assumptions that management believes to be reasonable under the circumstances. Actual results may differ from those estimates. Estimates and assumptions about future events and their effects cannot be determined with certainty and therefore require the exercise of judgment. As of the date of issuance of these financial statements, the Company is not aware of any specific event or circumstance that would require the Company to update its estimates, assumptions and judgments or revise the carrying value of its assets or liabilities. These estimates may change as new events occur and additional information is obtained and are recognized in the consolidated financial statements as soon as they become known. Actual results could differ from those estimates and any such differences may be material to the Company’s consolidated financial statements. Foreign Currency Translation The functional currency of the Company’s non-U.S. subsidiary is the Australian dollar. Asset and liability balances denominated in non-U.S. dollar currency are translated into U.S. dollars using period-end exchange rates, while expenses are based upon the exchange rate at the time of the transaction, if known, or at the average rate for the period. Equity accounts, except for the change in accumulated deficit during the year, have been translated using historical exchange rates. Differences are included in stockholders’ equity as a component of accumulated other comprehensive loss. Cash and Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less at the time of purchase to be cash equivalents. Cash equivalents are stated at fair value. The Company has no restricted cash. Marketable Securities All marketable securities have been classified as “available-for-sale” and are carried at estimated fair value, based upon quoted market prices or pricing models for similar securities. The Company considers its available-for-sale portfolio as available for use in current operations. Accordingly, those marketable securities with contractual maturities greater than one year from the date of purchase are classified as current assets on the accompanying balance sheets. Unrealized gains and losses are excluded from earnings and are included in other comprehensive income or loss and reported as a separate component of stockholders’ equity or deficit until realized or until a determination is made that an other-than-temporary decline in market value has occurred. Realized gains and losses as well as credit losses, if any, on available-for-sale securities are included in other income (expense), net. The cost of securities sold is based on the specific-identification method. The amortized cost of debt securities is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion, together with interest on securities, are included in interest income on the Company’s consolidated statements of operations. In accordance with the Company’s investment policy, management invests to diversify credit risk and only invests in debt securities with high credit quality, including U.S. government securities. The Company regularly reviews all of its investments for other-than-temporary declines in estimated fair value. Its review includes the consideration of the cause of the impairment, including the creditworthiness of the security issuers, the number of securities in an unrealized loss position, the severity and duration of the unrealized losses, whether the Company has the intent to sell the securities and whether it is more likely than not that the Company will be required to sell the securities before the recovery of their amortized cost basis. If a credit loss does exist for available-for-sale debt securities and should be recognized, an allowance will be recorded rather than a write-down of the amortized cost basis. To date, no such credit losses have occurred or have been recorded. Concentration of Credit Risk Financial instruments that potentially expose the Company to significant concentrations of credit risk consist primarily of cash, cash equivalents and marketable securities. As of December 31, 2022, the majority of the Company’s cash, cash equivalents and marketable securities were held by financial institutions in the United States, while approximately $ 0.7 million was held by a financial institution in Australia. Such deposits in the United States were in excess of insured limits. Impairment of Long-Lived Assets Long-lived assets include property and equipment. The Company reviews the carrying value of its long-lived assets for possible impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. The Company recognizes an impairment loss when the total estimated future cash flows expected to result from the use of the asset and its eventual disposition are less than the carrying amount. Through December 31, 2022, there have been no such impairment losses. Property and Equipment Property and equipment are stated at cost, less accumulated depreciation. Depreciation on property and equipment is calculated on the straight-line method over the estimated useful lives of the assets. Furniture, laboratory and office equipment are depreciated over five to seven years . Computer equipment are depreciated over three years . Leasehold improvements are amortized over the shorter of their estimated useful lives or the related lease term. Other Assets Other assets consist of security deposits for the Company’s operating leases of office and laboratory space. Leases The Company determines if an arrangement contains a lease at inception of the contract and determines the classification of its leases at lease commencement. At lease commencement, the Company records a lease liability based on the present value of future lease payments over the expected lease term. The lease term used may include options to extend the lease when it is reasonably certain that the Company will exercise the option. The Company calculates the present value of lease payments using the discount rate implicit in the lease, unless that rate cannot be readily determined. In that case, the Company uses its incremental borrowing rate, which is the rate of interest that the Company would have to pay to borrow on a collateralized basis over a similar term, an amount equal to the lease payments in a similar economic environment. The Company records a corresponding right-of-use (“ROU”) lease asset based on the lease liability, adjusted for any lease incentives received and any initial direct costs paid to the lessor prior to the lease commencement date. After lease commencement, the Company measures its leases as follows: (i) the lease liability based on the present value of the remaining lease payments using the discount rate determined at lease commencement; and (ii) the ROU lease asset based on the remeasured lease liability, adjusted for any unamortized lease incentives received, any unamortized initial direct costs and the cumulative difference between rent expense and amounts paid under the lease agreement. Any lease incentives received and any initial direct costs are amortized on a straight-line basis over the expected lease term. Rent expense is recorded on a straight-line basis over the expected lease term. ROU lease asset and operating lease liabilities are remeasured upon reassessment events and modifications to leases using the present value of remaining lease payments and estimated incremental borrowing rate at the time of remeasurement, as applicable. The Company does not recognize ROU assets or lease liabilities for short-term leases with terms less than 12 months and separately accounts for lease and non-lease components for all of its leases. Debt Issuance Costs and Debt Discounts Debt issuance costs include legal fees, accounting fees, and other direct costs incurred in connection with the execution of the Company’s debt financing. Debt discounts represent costs paid to the lenders. Debt issuance costs and debt discounts are deducted from the carrying amount of the debt liability and are amortized to interest expense over the term of the related debt using the effective interest method. Research and Development Costs Research and development costs are expensed as incurred and consist primarily of salaries and benefits, stock-based compensation expense, lab supplies and facility costs, as well as fees paid to consultants and entities that conduct certain research and development activities on the Company’s behalf and expenses incurred in connection with license agreements. Nonrefundable advance payments for goods or services to be received in the future for use in research and development activities are capitalized and then expensed as the related goods are delivered or the services are performed. The Company records accrued expenses for estimated costs of our research and development activities conducted by third-party service providers, which include the conduct of clinical studies, contract manufacturing activities and preclinical studies. The Company determines the estimates by reviewing contracts, vendor agreements and purchase orders, and through discussions with our internal personnel and external service providers as to the progress or stage of completion of trials or services for the services when we have not yet been invoiced or notified of the actual progress and cost. Any payments made in advance of services provided are recorded as prepaid assets, which are expensed as the contracted services are performed. As actual costs become known, we adjust our accrued estimates. Although the Company do not expect its estimates to be materially different from amounts actually incurred, our understanding of the status and timing of services performed, the number of patients enrolled and the rate of patient enrollment may vary from its estimates and could result in us reporting amounts that are too high or too low in any particular period. Stock-Based Compensation Stock-based awards issued to employees, directors and nonemployee consultants, including stock options, are recorded at fair value as of the grant date using the Black-Scholes option pricing model and recognized as expense on a straight-line basis over the expected vesting period. Income Taxes Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. The Company records a valuation allowance against deferred tax assets if it is more likely than not that a portion or all of the asset will not be realized in future periods. In making such determination, the Company considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax planning strategies and recent financial operations. The Company recognizes benefits of uncertain tax positions if it is more likely than not that such positions will be sustained upon examination based solely on their technical merits, as the largest amount of benefit that is more likely than not to be realized upon the ultimate settlement. The Company’s policy is to recognize interest and penalties related to the underpayment of income taxes as a component of income tax expense or benefit. To date, there have been no interest charges or penalties related to unrecognized tax benefits. Net Loss per Share Basic net loss per share is calculated by dividing the net loss by the weighted average number of shares of common stock and pre-funded warrants outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is the same as basic net loss per share for the periods presented since the effects of potentially dilutive securities are antidilutive given the net loss of the Company. The pre-funded warrants are included in the computation of basic and diluted net loss per common share as the exercise price is negligible and the pre-funded warrants are fully vested and exercisable. Common share equivalents are only included in the calculation of diluted net loss per common share when their effect is dilutive. Recently Issued Accounting Pronouncements There have been no recent accounting pronouncements, changes in accounting pronouncements or recently adopted accounting guidance that are of significance or potential significance to the Company.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. Fair Value Measurements Financial assets and liabilities are recorded at fair value. The carrying amount of certain financial instruments, including cash, cash equivalents, other current assets, accounts payable and accrued liabilities, approximate fair value due to their relatively short maturities. Assets and liabilities recorded at fair value on a recurring basis in the consolidated balance sheets are categorized based upon the level of judgment associated with the inputs used to measure their fair values. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The authoritative guidance on fair value measurements establishes a three-tier fair value hierarchy for disclosure of fair value measurements as follows: Level 1 : Quoted prices in active markets for identical assets or liabilities. Level 2 : Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 : Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires management to make judgments and consider factors specific to the asset or liability. The Company applies fair value accounting for all financial assets and liabilities and nonfinancial assets and liabilities that are required to be recognized or disclosed at fair value in the financial statements. The Company determines the fair value of Level 1 assets using quoted prices in active markets for identical assets. The Company reviews trading activity and pricing for Level 2 investments as of each measurement date. Level 2 inputs, which are obtained from various third-party data providers, represent quoted prices for similar assets in active markets and were derived from observable market data, or, if not directly observable, were derived from or corroborated by other observable market data. In certain cases, where there is limited activity or less transparency around inputs to valuation, securities are classified as Level 3 within the valuation hierarchy. The Company did not have any assets or liabilities measured using Level 3 inputs as of December 31, 2022 or 2021. The following table summarizes the Company’s financial assets measured at fair value on a recurring basis and classified under the appropriate level of the fair value hierarchy as described above (in thousands): December 31, 2022 Total Level 1 Level 2 Level 3 Financial Assets: Cash equivalents: U.S. Treasury money market funds $ 38,745 $ 38,745 $ — $ — Marketable securities: U.S. Treasury securities 40,141 40,141 — — Commercial paper 117,478 — 117,478 — Corporate debt securities 1,978 — 1,978 — U.S. Government agency bonds 76,508 — 76,508 — Total $ 274,850 $ 78,886 $ 195,964 $ — December 31, 2021 Total Level 1 Level 2 Level 3 Financial Assets: Cash equivalents: U.S. Treasury money market funds $ 60,375 $ 60,375 $ — $ — Marketable securities: U.S. Treasury securities 82,106 82,106 — — Commercial paper 46,687 — 46,687 — Corporate debt securities 15,481 — 15,481 — U.S. agency bonds 1,199 — 1,199 — Total $ 205,848 $ 142,481 $ 63,367 $ —

Available-for-Sale Securities

Available-for-Sale Securities	12 Months Ended
	Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Available-for-Sale Securities	4. Available-for-Sale Securities The following table is a summary of available-for-sale securities recorded in cash and cash equivalents or marketable securities in the Company’s consolidated balance sheets as of December 31, 2022 and 2021 (in thousands): December 31, 2022 Amortized Unrealized Unrealized Fair Cash equivalents: U.S. Treasury money market funds $ 38,745 $ — $ — $ 38,745 Marketable securities: U.S. Treasury securities 40,340 — ( 199 ) 40,141 Commercial paper 117,855 2 ( 379 ) 117,478 Corporate debt securities 1,978 — — 1,978 U.S. Government agency bonds 76,610 56 ( 158 ) 76,508 Total $ 275,528 $ 58 $ ( 736 ) $ 274,850 Cash 1,711 Total cash, cash equivalent and marketable securities $ 276,561 December 31, 2021 Amortized Cost Unrealized Unrealized Fair Value Cash equivalents: U.S. Treasury money market funds $ 60,375 $ — $ — $ 60,375 Marketable securities: U.S. Treasury securities 82,204 — ( 98 ) 82,106 Commercial paper 46,678 13 ( 4 ) 46,687 Corporate debt securities 15,486 — ( 5 ) 15,481 U.S. agency bonds 1,200 — ( 1 ) 1,199 Total available-for-sale securities $ 205,943 $ 13 $ ( 108 ) $ 205,848 Cash 2,507 Total cash, cash equivalent and marketable securities $ 208,355 The Company has no t recognized an allowance for credit losses on any securities in an unrealized loss position as of December 31, 2022 and 2021. The following tables display additional information regarding gross unrealized losses and fair value by major security type for available-for-sale securities in an unrealized loss position as of December 31, 2022 and 2021 (in thousands): December 31, 2022 Less than 12 months 12 months or greater Fair Value Unrealized Losses Fair Value Unrealized Losses U.S. Treasury securities $ 33,782 $ ( 196 ) $ 6,359 $ ( 3 ) Commercial paper 112,706 ( 379 ) — — Corporate debt securities 1,978 — — — U.S. agency bonds 33,942 ( 147 ) 5,490 ( 11 ) Total $ 182,408 $ ( 722 ) $ 11,849 $ ( 14 ) December 31, 2021 Less than 12 months 12 months or greater Fair Value Unrealized Losses Fair Value Unrealized Losses U.S. Treasury securities $ 82,106 $ ( 98 ) $ — $ — Commercial paper 13,734 ( 4 ) — — Corporate debt securities 15,481 ( 5 ) — — U.S. agency bonds 1,199 ( 1 ) — — Total $ 112,520 $ ( 108 ) $ — $ — The Company believes that the individual unrealized losses represent temporary declines primarily resulting from interest rate changes, and intends to hold these marketable securities to their maturities. As of December 31, 2022, the amortized cost and estimated fair value of the Company’s available-for-sale securities by contractual maturity are shown below (in thousands): Amortized Estimated Cost Fair Value Available-for-sale securities maturing in: One year or less $ 263,664 $ 263,001 One to two years 11,864 11,849 Total available-for-sale securities $ 275,528 $ 274,850 The Company currently does not intend to sell these securities prior to maturity and does not consider these investments to be other-than-temporarily impaired at December 31, 2022. There were no sales of available-for-sale securities in any of the periods presented.

Balance Sheet Components

Balance Sheet Components	12 Months Ended
	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Balance Sheet Components	5. Balance Sheet Components Property and Equipment, Net Property and equipment, net consisted of the following as of December 31, 2022 and 2021 (in thousands): December 31, December 31, Leasehold improvements $ 3,366 $ 3,268 Furniture, laboratory and office equipment 4,423 3,423 Computer equipment 244 244 Total property and equipment 8,033 6,935 Less: accumulated depreciation and amortization ( 4,602 ) ( 3,652 ) Property and equipment, net $ 3,431 $ 3,283 Depreciation expense was $ 1.0 million, $ 0.9 million, and $ 0.9 million for the year ended December 31, 2022, 2021, and 2020, respectively. Accrued Liabilities Accrued liabilities consisted of the following as of December 31, 2022 and 2021 (in thousands): December 31, December 31, Accrued preclinical and research costs $ 1,368 $ 1,043 Accrued clinical costs 1,007 1,642 Accrued employee-related costs 3,260 1,970 Accrued professional services 53 231 Other 265 99 Total accrued liabilities $ 5,953 $ 4,985

Lease

Lease	12 Months Ended
	Dec. 31, 2022
Leases [Abstract]
Lease	6. Lease In November 2022, the Company entered into an amendment to the lease agreement for its corporate headquarters in South San Francisco, California, which expands the leased premises to include Suite 400 in the same building as its corporate headquarters and extending the lease term of the original premises to be coterminous with the expansion premises to July 31, 2026 . The transaction was treated as a lease modification as of the effective date and resulted in the recognition of approximately $ 8.0 million in new lease liabilities and right-of-use assets. The contractually specified minimum rent and annual rent increases for the operating lease are included in the measurement of the ROU asset and related lease liabilities. Under the lease arrangement, the Company may be required to pay directly, or reimburse the lessor for real estate taxes, insurance, utilities, maintenance and other operating costs. Such amounts are variable and therefore not included in the measurement of the ROU asset and related lease liability but are instead recognized as variable lease expense in the Company’s Consolidated Statements of Operations when they are incurred. The operating lease agreement has one option to extend the lease term for a period of five years at the fair market rate at the time of the extension. The option to extend the lease was not recognized as part of the Company’s lease liability and ROU asset as the Company determined the renewal rent costs are uncertain and the option is not reasonably certain to be exercised. As of December 31, 2022, the weighted average remaining lease term was 3.58 years and the weighted average discount rate used to determine the operating lease liability was 11.67 %. Information related to the Company’s ROU asset and related lease liabilities were as follows (in thousands): For the Year Ended December 31, 2022 2021 2020 Cash paid for operating lease liabilities $ 1,032 $ 1,042 $ 900 Operating lease costs 1,493 1,099 1,099 Variable lease costs 807 765 542 Maturities of lease liabilities as of December 31, 2022 were as follows: Less than 12 months $ 3,767 13 - 24 months 3,890 25 - 36 months 4,025 37 - 48 months 2,418 Total undiscounted lease payments 14,100 Less: imputed interest ( 2,670 ) Total lease liabilities $ 11,430 Operating lease liabilities, current 2,565 Operating lease liabilities, noncurrent 8,865 Total operating lease liabilities $ 11,430 For the years ended December 31, 2022, 2021 and 2020, the Company recognized $ 1.5 million, $ 1.1 million and $ 1.1 million of rent expense, respectively. Variable lease costs were $ 0.8 million, $ 0.8 million and $ 0.5 million for the years ended December 31, 2022, 2021 and 2020, respectively.

Debt

Debt	12 Months Ended
	Dec. 31, 2022
Debt Disclosure [Abstract]
Debt	7. Debt In November 2021, the Company entered into a Loan Agreement with Oxford Finance, which provides the Company up to $ 50.0 million in borrowing capacity across five potential tranches. The initial tranche of $ 10.0 million was funded at the closing of the Loan Agreement. Subsequent tranches of $ 20.0 million each would become available upon achieving milestones related to the Company’s MISSION Phase 2 clinical trial and KZR-261 Phase 1 clinical trial, up to the aggregate maximum amount of $50.0 million. As of December 31, 2022, a total of $ 40.0 million in borrowing capacity remained available to us under the Loan Agreement across two potential tranches. The loan facility is secured by all assets except intellectual property, which has a negative pledge, and will mature on November 1, 2026 . There are no warrants or financial covenants associated with the Loan Agreement. The term loans bear interest at a floating per annum rate (based on the actual number of days elapsed divided by a year of 360 days) equal to the sum of (a) the greater of (i) 30-day U.S. LIBOR rate reported in the Wall Street Journal on the last business day of the month that immediately precedes the month in which the interest will accrue and (ii) 0.08 %, plus (b) 7.87 %. The Company is required to make monthly interest-only payments prior to the amortization date of January 1, 2025, subject to a potential one-year extension upon satisfaction of certain conditions. Upon the occurrence of a LIBOR transition event, Oxford Finance may amend the Loan Agreement to replace the LIBOR rate with a LIBOR Replacement Rate. All unpaid principal and accrued and unpaid interest with respect to each term loan is due and payable in full on November 1, 2026 (the “Maturity Date”). The Company has the option to prepay the outstanding balance prior to maturity, subject to a prepayment fee of 1.0 % to 2.0 % depending upon when the prepayment occurs. Upon repayment of the Term Loans, the Company is required to make a final payment fee to the Lenders equal to 6.5 % of the original principal amount of the Term Loans funded which will be accrued by charges to interest expense over the term of the loans using the effective interest method. The Agreement also includes subjective acceleration clauses which permit the lenders to accelerate the Maturity Date under certain circumstances, including, but not limited to, material adverse effects on a Company’s financial status or otherwise. As of December 31, 2022, the Company is in compliance with all covenants in Agreement. Interest expense was $ 1.2 million and $ 0.2 million for the year ended December 31, 2022 and 2021, respectively. The effective interest rate on the term loans, including the amortization of the debt discount and issuance costs, and accretion of the final payment, was 11 %. The components of the long-term debt balance are as follows: December 31, December 31, Principal loan balance $ 10,000 $ 10,000 Unamortized debt discount and issuance costs ( 342 ) ( 431 ) Cumulative accretion of final fee 176 53 Long-term debt, net $ 9,834 $ 9,622 As of December 31, 2022, the estimated future principal payments due were as follows: Years Ending December 31, 2023 $ — 2024 — 2025 5,217 2026 4,783 Total $ 10,000

Pre-Funded Warrants

Pre-Funded Warrants	12 Months Ended
	Dec. 31, 2022
Equity [Abstract]
Pre-Funded Warrants	8. Pre-Funded Warrants In February 2020, the Company completed the February Offering, which included the issuance and sale of pre-funded warrants to purchase 2,884,615 shares of its common stock. The public offering price of the pre-funded warrants was $ 2.599 per underlying share. In June 2020, the Company completed the June Offering, which included the issuance and sale of pre-funded warrants to purchase 909,091 shares of its common stock. The public offering price of the pre-funded warrants was $ 5.499 per underlying share. Each pre-funded warrant entitles the holder to purchase shares of common stock at an exercise price of $ 0.001 per share and expires 20 years from the date of issuance. These warrants were recorded as a component of stockholders’ equity within additional paid-in capital. Per the terms of the warrant agreement, a holder of the outstanding warrant is not entitled to exercise any portion of the pre-funded warrant if, upon exercise of such portion of the warrant, the holder’s ownership of the Company’s common stock (together with its affiliates) or the combined voting power of the Company’s securities beneficially owned by such holder (together with its affiliates) would exceed 4.99 % after giving effect to the exercise (“Maximum Ownership Percentage”). Upon at least 61 days’ prior notice to the Company by the warrant holder, any warrant holder may increase or decrease the Maximum Ownership Percentage to any other percentage not to exceed 19.99 %. As of December 31, 2022, no shares underlying the pre-funded warrants have been exercised. The following table represents a summary of the pre-funded warrants outstanding as of December 31, 2022. Issue Date Classification Exercise price Expiration Date Number of shares underlying February 4, 2020 Equity $ 0.001 February 4, 2040 2,884,615 June 11, 2020 Equity $ 0.001 June 11, 2040 909,091 Total Outstanding 3,793,706 On January 6, 2023, investors exercised 2,236,553 pre-funded warrants at an exercise price of $ 0.001 per share.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	9. Stock-Based Compensation Stock Incentive Plans 2022 Inducement Plan In April 2022, the Company adopted the Kezar Life Sciences, Inc. 2022 Inducement Plan (the “Inducement Plan”), which is a non-stockholder approved stock plan adopted pursuant to the “inducement exception” provided under Nasdaq Listing Rule 5635(c)(4), for the award of nonstatutory stock options (“NSOs”), restricted stock units (“RSUs”) and other equity awards as permitted by the Inducement Plan (collectively, “Inducement Awards”) to persons not previously an employee or director of the Company, or following a bona fide period of non-employment, as an inducement material to such persons entering into employment with the Company (“Eligible Recipients”). Under the Inducement Plan, the Company may grant up to 3,000,000 shares of Common Stock in the form of Inducement Awards to Eligible Recipients in compliance with the requirements of Nasdaq Listing Rule 5635(c)(4). Awards must be approved by either a majority of the Company’s independent directors or the Company’s independent compensation committee. Consultants and directors are not eligible to received grants under the Inducement Plan. As of December 31, 2022, options to purchase 624,000 shares of common stock were outstanding and 2,376,000 shares were available for future issuance under the Inducement Plan. 2018 Equity Incentive Plan In June 2018, the Company’s board of directors adopted and its stockholders approved the 2018 Equity Incentive Plan (the “2018 Plan”), which became effective as of June 20, 2018, at which point no further grants could be made under the 2015 Equity Incentive Plan (the “2015 Plan”) described below. Under the 2018 Plan, the Company may grant ISOs, NSOs, stock appreciation rights, restricted stock awards, RSUs and other stock-based awards. As of December 31, 2022, options to purchase 7,532,708 shares of common stock were outstanding and 782,397 shares were available for future issuance under the 2018 Plan. Initially, subject to adjustment as provided in the 2018 Plan, the aggregate number of shares of the Company’s common stock authorized for issuance pursuant to stock awards under the 2018 Plan was 4,000,000 shares, which is the sum of (i) 1,600,692 shares plus (ii) the number of shares reserved and available for issuance under the 2015 Plan at the time the 2018 Plan became effective and (iii) the number of shares subject to stock options or other stock awards granted under the 2015 Plan that expire, terminate, are forfeited or otherwise not issued, or are withheld to satisfy a tax withholding obligation in connection with an award or to satisfy a purchase or exercise price of an award (such as upon the expiration or termination of a stock award prior to vesting). The number of shares of the Company’s common stock reserved for issuance under the 2018 Plan automatically increases on January 1 of each year, beginning on January 1, 2019 and continuing through and including January 1, 2028 , by 5 % of the total number of shares of capital stock outstanding on December 31 of the preceding calendar year, or a lesser number of shares determined by the Company’s board of directors prior to such increase. On January 1, 2022, 2,812,987 shares were added to the 2018 Plan reserve and are available for issuance. The maximum number of shares that may be issued upon the exercise of ISOs under the 2018 Plan is 12,500,000 shares. 2015 Equity Incentive Plan The Company’s 2015 Plan provided for the granting of ISOs and NSOs to employees, directors and consultants at the discretion of the board of directors. The 2015 Plan was terminated as to future awards in June 2018, although it continues to govern the terms of options that remain outstanding under the 2015 Plan. No additional stock awards will be granted under the 2015 Plan, and all outstanding stock awards granted under the 2015 Plan that are repurchased, forfeited, expire or are cancelled will become available for grant under the 2018 Plan in accordance with its terms. Options granted under the 2015 Plan expire no later than 10 years from the date of grant. Options granted under the 2015 Plan vest over periods determined by the board of directors, generally over four years . The 2015 Plan allows for early exercise of certain options prior to vesting. Upon termination of employment, the unvested shares are subject to repurchase at the original exercise price. As of December 31, 2022, options to purchase 1,528,102 shares of common stock were outstanding under the 2015 Plan. 2018 Employee Stock Purchase Plan In June 2018, the Company’s board of directors adopted and its stockholders approved the 2018 Employee Stock Purchase Plan (the “ESPP”), which became effective as of June 20, 2018. The ESPP is intended to qualify as an “employee stock purchase plan” within the meaning of Section 423 of the U.S. Internal Revenue Code of 1986, as amended (the “Code”). The number of shares of common stock initially reserved for issuance under the ESPP was 200,000 shares. The ESPP provides for an annual increase on January 1 of each year, beginning on January 1, 2019 and continuing through and including January 1, 2028, equal to the lesser of (i) 1 % of the shares of common stock outstanding on the last day of the prior fiscal year or (ii) 375,000 shares, or a lesser number of shares determined by the Company’s board of directors prior to such increase. As of December 31, 2022, 378,237 shares of common stock had been issued under the ESPP and 954,987 shares remained available for future issuance under the ESPP. On January 1, 2022, 375,000 shares were added to the ESPP reserve and are available for issuance. The price per share of common stock to be paid by an ESPP participant on the applicable purchase date of an offering period shall be equal to 85 % of the lesser of the fair market value of a share of common stock on (i) the applicable offering date or (ii) the applicable purchase date. The Company’s board of directors authorized an initial six-month offering period beginning on November 16, 2018 and ending on May 15, 2019 . The Company’s board of directors has subsequently authorized additional six-month offering periods, with the most recent offering period beginning on November 16, 2022 . Stock Option Activity The following table summarizes activity under the Company’s stock option plans and related information (in thousands, except share and per share amounts): Number of Weighted Weighted Average Aggregate Outstanding at December 31, 2021 6,945,184 $ 5.95 7.9 $ 77,363 Options granted 3,036,235 $ 12.80 Options exercised ( 189,978 ) $ 3.44 $ 1,504 Options cancelled/forfeited ( 106,631 ) $ 8.02 Outstanding at December 31, 2022 9,684,810 $ 8.12 7.6 $ 15,407 Vested and exercisable at December 31, 2022 5,063,304 $ 6.85 6.7 $ 11,532 The weighted average grant date fair value of options granted during the years ended December 31, 2022 and 2021 was $ 9.81 and $ 4.20 per share, respectively. The aggregate intrinsic value of exercised stock options during the years ended December 31, 2022 and 2021 was $ 1.5 million and $ 2.1 million, respectively. The aggregate intrinsic value is calculated as the difference between the exercise price and the estimated fair value of the Company’s common stock at the date of exercise. Restricted Stock Units During the 12 months ended December 31, 2022, the Company granted RSUs to certain employees pursuant to the 2018 Plan. One-third of each RSU grant will vest annually following the vesting commencement dates, over a vesting period of 3 years . RSUs are awards that entitle the holder to receive freely tradable shares of the Company's common stock upon vesting and are not forfeitable once fully vested. The valuations for these RSUs were based on the closing prices of the Company's common stock on the grant dates and recognized as stock-based compensation expense over the respective vesting terms. Number of RSUs Outstanding Weighted Average Grant-Date Fair Price Outstanding as of December 31, 2021 — RSUs granted 439,615 $ 9.81 RSUs vested — $ — RSUs forfeited ( 4,825 ) $ 10.60 Outstanding as of December 31, 2022 434,790 $ 9.80 Stock-Based Compensation Expense Total stock-based compensation expense recognized by function was as follows (in thousands): Year Ended December 31, 2022 2021 2020 Research and development $ 6,612 $ 2,955 $ 2,102 General and administrative 7,394 4,641 2,841 Total stock-based compensation expense $ 14,006 $ 7,596 $ 4,943 As of December 31, 2022, the unrecognized stock-based compensation cost was $ 33.1 million with an estimated weighted average amortization period of 2.5 years. The fair value of the employee stock options granted and the ESPP rights to purchase common stock of the Company is calculated using the Black-Scholes option-pricing model with the following weighted-average assumptions: Options ESPP Rights Year Ended December 31, Year Ended December 31, 2022 2021 2020 2022 2021 2020 Expected term (years) 5.5 - 6.1 5.5 - 6.1 5.5 - 6.0 0.5 0.5 0.5 Expected volatility 84.3 - 88.5 % 85.4 - 88.1 % 83.8 - 91.9 % 85.6 - 114.9 % 64.0 - 77.2 % 101.7 - 114.3 % Risk-free interest rate 1.6 - 4.1 % 0.5 - 1.3 % 0.4 - 1.6 % 1.5 - 4.5 % 0.0 - 0.1 % 0.1 - 0.2 % Expected dividend yield — — — — — — The expected term of options granted represents the period of time that options granted are expected to be outstanding and was determined by calculating the midpoint between the date of vesting and the contractual life of each option. The expected term of the ESPP rights is equal to the six-month look-back period. Volatility is based on the average of the historical volatility of the Company's stock price and that of a peer group of public companies over the expected term. The peer group was selected on the basis of operational and economic similarity with the Company’s principal business operations. The risk-free interest rate for the expected term of the options is based on the U.S. Treasury yield curve with a maturity equal to the expected term in effect at the time of grant. The Company has no t paid, and does not anticipate paying, cash dividends on its shares of common stock; therefore, the expected dividend yield is zero .

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	10. Commitments & Contingencies Indemnification In the ordinary course of business, the Company enters into agreements that may include indemnification provisions. Pursuant to such agreements, the Company may indemnify, hold harmless and defend an indemnified party for losses suffered or incurred by the indemnified party. Some of the provisions will limit losses to those arising from third-party actions. In some cases, the indemnification will continue after the termination of the agreement. The maximum potential amount of future payments the Company could be required to make under these provisions is not determinable. The Company has never incurred material costs to defend lawsuits or settle claims related to these indemnification provisions. The Company has also entered into indemnification agreements with its directors and officers that may require the Company to indemnify its directors and officers against liabilities that may arise by reason of their status or service as directors or officers to the fullest extent permitted by California corporate law. The Company currently has directors’ and officers’ insurance.

License Agreement

License Agreement	12 Months Ended
	Dec. 31, 2022
License Agreement [Abstract]
License Agreement	11. License Agreement In June 2015, the Company entered into an exclusive license agreement with Onyx Therapeutics, Inc. (“Onyx”), a wholly owned subsidiary of Amgen, Inc., for a worldwide, exclusive license under certain patents, and a non-exclusive license to certain know-how, in each case controlled by Onyx and relating to the Company’s immunoproteasome program. The Company may be required to make future payments of up to $ 172.5 million upon achievement of certain development and commercial milestones for zetomipzomib, as well as royalty payments in the mid to high single digits on future annual net sales, if any.

Defined Contribution Plan

Defined Contribution Plan	12 Months Ended
	Dec. 31, 2022
Retirement Benefits [Abstract]
Defined Contribution Plan	12. Defined Contribution Plan The Company has a qualified 401(k) Savings and Investment Plan (the “Plan”) whereby employees may contribute up to the lesser of $ 56,000 or 100 % of their pre-tax compensation. The total contributed amount from the employees is only up to Federal annual limits. The Company matches $ 1.00 for every $ 1.00 contributed to the Plan by participants up to the first 4 % of base compensation and incentive cash bonus (subject to statutory limits). During the years ended December 31, 2022, 2021 and 2020, the Company recorded matching contributions of approximately $ 0.6 million, $ 0.4 million and $ 0.3 million, respectively.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Income Taxes	13. Income Taxes No provision for income taxes was recorded for the years ended December 31, 2022, 2021 and 2020. The U.S. federal deferred tax assets generated from the Company’s net operating losses have been fully reserved, as the Company believes it is not more likely than not that the benefit will be realized. The following table presents domestic and foreign components of net loss for the periods presented (in thousands): Year Ended December 31, 2022 2021 2020 Domestic $ ( 68,097 ) $ ( 54,581 ) $ ( 41,599 ) Foreign ( 142 ) ( 49 ) ( 143 ) Total $ ( 68,239 ) $ ( 54,630 ) $ ( 41,742 ) In December 2015, the Protecting Americans from Tax Hikes Act of 2015 (“PATH”) was signed into law, which created several new research and development (“R&D”) tax credit provisions, including allowing qualified small businesses to utilize the R&D credit against the employer’s portion of payroll tax up to a maximum of $ 250,000 per year. The Company qualified as a small business under PATH for years 2016 through 2020. The Company has utilized $ 79,000 , $ 325,000 and $ 373,000 of R&D tax credits as a reduction of payroll expenses to offset its payroll tax liabilities for the years ended December 31, 2022, 2021 and 2020, respectively. The effective tax rate of the provision for income taxes differs from the federal statutory rate as follows: Year Ended December 31, 2022 2021 2020 Federal statutory income tax rate 21.0 % 21.0 % 21.0 % State taxes, net of federal benefit 1.3 1.3 1.1 Foreign tax rate differential 0.0 0.0 0.0 Permanent differences ( 0.6 ) ( 2.2 ) ( 2.7 ) Research and development credit 2.5 4.0 2.6 Change in valuation allowance ( 24.2 ) ( 24.1 ) ( 22.0 ) Provision for income taxes — % — % — % The components of the deferred tax assets and liabilities are as follows (in thousands): Year Ended December 31, 2022 2021 Deferred tax assets Reserves and accruals $ 3,420 $ 2,043 Net operating loss carryforwards 37,939 34,617 Research and development credit carryforwards 7,603 5,127 Lease Liabilities 2,402 929 R&D Capitalization 7,979 — Gross deferred tax assets 59,343 42,716 Valuation allowance ( 56,983 ) ( 41,771 ) Net deferred tax assets 2,360 945 Deferred tax liabilities Property and equipment ( 313 ) ( 375 ) Right-of-use asset ( 2,047 ) ( 570 ) Net deferred tax assets $ — $ — Effective January 1, 2022, under the Tax Cuts and Jobs Act, for tax purposes the Company is required to capitalize and subsequently amortize all R&D expenditures over five years for research activities conducted in the U.S. and over fifteen years for research activities conducted outside of the U.S. The Company generates a deferred tax asset for capitalized R&D expenditures for the year ended December 31, 2022 which is fully offset with a valuation allowance. Realization of the deferred tax assets is dependent upon future taxable income. Since the amount and timing of future income are uncertain, the net deferred tax assets, as of December 31, 2022, and December 31, 2021 have been fully offset by a valuation allowance. The valuation allowance increased approximately $ 15.2 million, $ 12.4 million and $ 9.2 million during the years ended December 31, 2022, 2021, and 2020, respectively. As of December 31, 2022, the Company had federal net operating loss (“NOL”) carryforward of $ 172.2 million and a federal research and development tax credit carryforward of $ 7.0 million. If not utilized sooner, the federal NOL generated through December 31, 2017 and tax credit carryforwards will expire, beginning in 2035 . Federal net operating loss carryforwards of $ 150.1 million generated from years ended after December 31, 2017, carryforward indefinitely. As of December 31, 2022 the Company had a state NOL carryforward of $ 17.4 million, which will expire beginning in 2035 , and a state research and development tax credit carryforward of $ 3.7 million, which does not expire. As of December 31, 2022, the Company also had accumulated Australian tax losses of $ 1.9 million available for carry forward against future earnings, which under relevant tax laws do not expire but may not be available under certain circumstances. In general, if the Company experiences a greater than 50 percentage point aggregate change in ownership over a three-year period (a Section 382 ownership change), utilization of the Company’s pre-change NOL carryforwards is subject to an annual limitation under Section 382 of the Code and similar California laws. The annual limitation generally is determined by multiplying the value of the Company’s stock at the time of such ownership change (subject to certain adjustments) by the applicable long-term tax-exempt rate. Such limitations may result in expiration of a portion of the NOL carryforwards before utilization. The Company has not utilized any NOL carryforwards through December 31, 2022. In addition, the Company’s deferred tax assets are subject to a full valuation allowance, and thus no benefit for deferred tax assets is recorded on the Company’s books. The Company’s ability to use the remaining NOL carryforwards may be further limited if the Company experiences a Section 382 ownership change as a result of future changes in the Company’s stock ownership. The Company had $ 2.5 million of unrecognized tax benefits as of December 31, 2022. No liability related to uncertain tax positions is recorded on the financial statements. All uncertain tax positions are currently recorded as a reduction to the Company’s deferred tax assets, which are subject to a valuation allowance. If recognized, none of the unrecognized tax benefits would affect the effective tax rate. The Company does not anticipate that the total amounts of unrecognized tax benefits will significantly increase or decrease in the next 12 months. The Company’s policy is to include interest and penalties related to unrecognized tax benefits within the provision for income taxes, as necessary. The Company did no t recognize any accrued interest and penalties related to gross unrecognized tax benefits related to the year ended December 31, 2022. A reconciliation of the Company’s unrecognized tax benefits for the year ended December 31, 2022, 2021 and 2020 is as follows (in thousands): Year Ended December 31, 2022 2021 Balance at the beginning of the year $ 1,643 $ 868 Decrease related to prior year tax positions ( 187 ) — Increase related to current year tax positions 1,066 775 Balance at the end of the year $ 2,522 $ 1,643 The Company files income tax returns in the United States federal jurisdiction, state jurisdictions and Australia. The Company currently has no federal, state or other jurisdictional tax examinations in progress. All years are open for examination by federal, state and Australian authorities.

Net Loss per Share

Net Loss per Share	12 Months Ended
	Dec. 31, 2022
Earnings Per Share [Abstract]
Net Loss Per Share	14. Net Loss Per Share Net Loss Per Share The following table sets forth the calculation of basic and diluted net loss per share during the periods presented (in thousands, except share and per share data): Year Ended December 31, 2022 2021 2020 Numerator: Net loss $ ( 68,239 ) $ ( 54,630 ) $ ( 41,742 ) Denominator: Weighted-average shares of common stock outstanding 67,368,935 52,759,335 44,004,190 Net loss per share, basic and diluted $ ( 1.01 ) $ ( 1.04 ) $ ( 0.95 ) The following outstanding shares of common stock equivalents were excluded from the computation of the diluted net loss per share for the periods presented because their effect would have been anti-dilutive: Year Ended December 31, 2022 2021 2020 Options to purchase common stock 9,684,810 6,945,184 4,489,122 Restricted stock units subject to future vesting 434,790 — — Common stock subject to future vesting — — 8,859 Total 10,119,600 6,945,184 4,497,981

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Basis of presentation and consolidation	Basis of Presentation and Consolidation The consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) and include the Company’s accounts and those of its wholly owned Australian subsidiary, Kezar Life Sciences Australia Pty Ltd, which is a proprietary company limited by shares. All intercompany balances and transactions have been eliminated upon consolidation.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Significant items subject to such estimates and assumptions include the valuation of marketable securities, stock-based compensation, and accrued research and development costs. Management bases its estimates on historical experience and on various other market-specific relevant assumptions that management believes to be reasonable under the circumstances. Actual results may differ from those estimates. Estimates and assumptions about future events and their effects cannot be determined with certainty and therefore require the exercise of judgment. As of the date of issuance of these financial statements, the Company is not aware of any specific event or circumstance that would require the Company to update its estimates, assumptions and judgments or revise the carrying value of its assets or liabilities. These estimates may change as new events occur and additional information is obtained and are recognized in the consolidated financial statements as soon as they become known. Actual results could differ from those estimates and any such differences may be material to the Company’s consolidated financial statements.
Foreign Currency Translation	Foreign Currency Translation The functional currency of the Company’s non-U.S. subsidiary is the Australian dollar. Asset and liability balances denominated in non-U.S. dollar currency are translated into U.S. dollars using period-end exchange rates, while expenses are based upon the exchange rate at the time of the transaction, if known, or at the average rate for the period. Equity accounts, except for the change in accumulated deficit during the year, have been translated using historical exchange rates. Differences are included in stockholders’ equity as a component of accumulated other comprehensive loss.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less at the time of purchase to be cash equivalents. Cash equivalents are stated at fair value. The Company has no restricted cash.
Marketable Securities	Marketable Securities All marketable securities have been classified as “available-for-sale” and are carried at estimated fair value, based upon quoted market prices or pricing models for similar securities. The Company considers its available-for-sale portfolio as available for use in current operations. Accordingly, those marketable securities with contractual maturities greater than one year from the date of purchase are classified as current assets on the accompanying balance sheets. Unrealized gains and losses are excluded from earnings and are included in other comprehensive income or loss and reported as a separate component of stockholders’ equity or deficit until realized or until a determination is made that an other-than-temporary decline in market value has occurred. Realized gains and losses as well as credit losses, if any, on available-for-sale securities are included in other income (expense), net. The cost of securities sold is based on the specific-identification method. The amortized cost of debt securities is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion, together with interest on securities, are included in interest income on the Company’s consolidated statements of operations. In accordance with the Company’s investment policy, management invests to diversify credit risk and only invests in debt securities with high credit quality, including U.S. government securities. The Company regularly reviews all of its investments for other-than-temporary declines in estimated fair value. Its review includes the consideration of the cause of the impairment, including the creditworthiness of the security issuers, the number of securities in an unrealized loss position, the severity and duration of the unrealized losses, whether the Company has the intent to sell the securities and whether it is more likely than not that the Company will be required to sell the securities before the recovery of their amortized cost basis. If a credit loss does exist for available-for-sale debt securities and should be recognized, an allowance will be recorded rather than a write-down of the amortized cost basis. To date, no such credit losses have occurred or have been recorded.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially expose the Company to significant concentrations of credit risk consist primarily of cash, cash equivalents and marketable securities. As of December 31, 2022, the majority of the Company’s cash, cash equivalents and marketable securities were held by financial institutions in the United States, while approximately $ 0.7 million was held by a financial institution in Australia. Such deposits in the United States were in excess of insured limits.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets Long-lived assets include property and equipment. The Company reviews the carrying value of its long-lived assets for possible impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. The Company recognizes an impairment loss when the total estimated future cash flows expected to result from the use of the asset and its eventual disposition are less than the carrying amount. Through December 31, 2022, there have been no such impairment losses.
Property and Equipment	Property and Equipment Property and equipment are stated at cost, less accumulated depreciation. Depreciation on property and equipment is calculated on the straight-line method over the estimated useful lives of the assets. Furniture, laboratory and office equipment are depreciated over five to seven years . Computer equipment are depreciated over three years . Leasehold improvements are amortized over the shorter of their estimated useful lives or the related lease term.
Other Assets	Other Assets Other assets consist of security deposits for the Company’s operating leases of office and laboratory space.
Leases	Leases The Company determines if an arrangement contains a lease at inception of the contract and determines the classification of its leases at lease commencement. At lease commencement, the Company records a lease liability based on the present value of future lease payments over the expected lease term. The lease term used may include options to extend the lease when it is reasonably certain that the Company will exercise the option. The Company calculates the present value of lease payments using the discount rate implicit in the lease, unless that rate cannot be readily determined. In that case, the Company uses its incremental borrowing rate, which is the rate of interest that the Company would have to pay to borrow on a collateralized basis over a similar term, an amount equal to the lease payments in a similar economic environment. The Company records a corresponding right-of-use (“ROU”) lease asset based on the lease liability, adjusted for any lease incentives received and any initial direct costs paid to the lessor prior to the lease commencement date. After lease commencement, the Company measures its leases as follows: (i) the lease liability based on the present value of the remaining lease payments using the discount rate determined at lease commencement; and (ii) the ROU lease asset based on the remeasured lease liability, adjusted for any unamortized lease incentives received, any unamortized initial direct costs and the cumulative difference between rent expense and amounts paid under the lease agreement. Any lease incentives received and any initial direct costs are amortized on a straight-line basis over the expected lease term. Rent expense is recorded on a straight-line basis over the expected lease term. ROU lease asset and operating lease liabilities are remeasured upon reassessment events and modifications to leases using the present value of remaining lease payments and estimated incremental borrowing rate at the time of remeasurement, as applicable. The Company does not recognize ROU assets or lease liabilities for short-term leases with terms less than 12 months and separately accounts for lease and non-lease components for all of its leases.
Debt Issuance Costs and Debt Discounts	Debt Issuance Costs and Debt Discounts Debt issuance costs include legal fees, accounting fees, and other direct costs incurred in connection with the execution of the Company’s debt financing. Debt discounts represent costs paid to the lenders. Debt issuance costs and debt discounts are deducted from the carrying amount of the debt liability and are amortized to interest expense over the term of the related debt using the effective interest method.
Research and Development Costs	Research and Development Costs Research and development costs are expensed as incurred and consist primarily of salaries and benefits, stock-based compensation expense, lab supplies and facility costs, as well as fees paid to consultants and entities that conduct certain research and development activities on the Company’s behalf and expenses incurred in connection with license agreements. Nonrefundable advance payments for goods or services to be received in the future for use in research and development activities are capitalized and then expensed as the related goods are delivered or the services are performed. The Company records accrued expenses for estimated costs of our research and development activities conducted by third-party service providers, which include the conduct of clinical studies, contract manufacturing activities and preclinical studies. The Company determines the estimates by reviewing contracts, vendor agreements and purchase orders, and through discussions with our internal personnel and external service providers as to the progress or stage of completion of trials or services for the services when we have not yet been invoiced or notified of the actual progress and cost. Any payments made in advance of services provided are recorded as prepaid assets, which are expensed as the contracted services are performed. As actual costs become known, we adjust our accrued estimates. Although the Company do not expect its estimates to be materially different from amounts actually incurred, our understanding of the status and timing of services performed, the number of patients enrolled and the rate of patient enrollment may vary from its estimates and could result in us reporting amounts that are too high or too low in any particular period.
Stock-Based Compensation	Stock-Based Compensation Stock-based awards issued to employees, directors and nonemployee consultants, including stock options, are recorded at fair value as of the grant date using the Black-Scholes option pricing model and recognized as expense on a straight-line basis over the expected vesting period.
Income Taxes	Income Taxes Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. The Company records a valuation allowance against deferred tax assets if it is more likely than not that a portion or all of the asset will not be realized in future periods. In making such determination, the Company considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax planning strategies and recent financial operations. The Company recognizes benefits of uncertain tax positions if it is more likely than not that such positions will be sustained upon examination based solely on their technical merits, as the largest amount of benefit that is more likely than not to be realized upon the ultimate settlement. The Company’s policy is to recognize interest and penalties related to the underpayment of income taxes as a component of income tax expense or benefit. To date, there have been no interest charges or penalties related to unrecognized tax benefits.
Net Loss per Share	Net Loss per Share Basic net loss per share is calculated by dividing the net loss by the weighted average number of shares of common stock and pre-funded warrants outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is the same as basic net loss per share for the periods presented since the effects of potentially dilutive securities are antidilutive given the net loss of the Company. The pre-funded warrants are included in the computation of basic and diluted net loss per common share as the exercise price is negligible and the pre-funded warrants are fully vested and exercisable. Common share equivalents are only included in the calculation of diluted net loss per common share when their effect is dilutive.
Recently Issued Accounting Pronouncements to be Adopted	Recently Issued Accounting Pronouncements There have been no recent accounting pronouncements, changes in accounting pronouncements or recently adopted accounting guidance that are of significance or potential significance to the Company.
Fair Value Measurements	Financial assets and liabilities are recorded at fair value. The carrying amount of certain financial instruments, including cash, cash equivalents, other current assets, accounts payable and accrued liabilities, approximate fair value due to their relatively short maturities. Assets and liabilities recorded at fair value on a recurring basis in the consolidated balance sheets are categorized based upon the level of judgment associated with the inputs used to measure their fair values. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The authoritative guidance on fair value measurements establishes a three-tier fair value hierarchy for disclosure of fair value measurements as follows: Level 1 : Quoted prices in active markets for identical assets or liabilities. Level 2 : Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 : Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires management to make judgments and consider factors specific to the asset or liability. The Company applies fair value accounting for all financial assets and liabilities and nonfinancial assets and liabilities that are required to be recognized or disclosed at fair value in the financial statements. The Company determines the fair value of Level 1 assets using quoted prices in active markets for identical assets. The Company reviews trading activity and pricing for Level 2 investments as of each measurement date. Level 2 inputs, which are obtained from various third-party data providers, represent quoted prices for similar assets in active markets and were derived from observable market data, or, if not directly observable, were derived from or corroborated by other observable market data.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Summary of Financial Assets Measured at Fair Value on a Recurring Basis	The following table summarizes the Company’s financial assets measured at fair value on a recurring basis and classified under the appropriate level of the fair value hierarchy as described above (in thousands): December 31, 2022 Total Level 1 Level 2 Level 3 Financial Assets: Cash equivalents: U.S. Treasury money market funds $ 38,745 $ 38,745 $ — $ — Marketable securities: U.S. Treasury securities 40,141 40,141 — — Commercial paper 117,478 — 117,478 — Corporate debt securities 1,978 — 1,978 — U.S. Government agency bonds 76,508 — 76,508 — Total $ 274,850 $ 78,886 $ 195,964 $ — December 31, 2021 Total Level 1 Level 2 Level 3 Financial Assets: Cash equivalents: U.S. Treasury money market funds $ 60,375 $ 60,375 $ — $ — Marketable securities: U.S. Treasury securities 82,106 82,106 — — Commercial paper 46,687 — 46,687 — Corporate debt securities 15,481 — 15,481 — U.S. agency bonds 1,199 — 1,199 — Total $ 205,848 $ 142,481 $ 63,367 $ —

Available-for-Sale Securities (

Available-for-Sale Securities (Tables)	12 Months Ended
	Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Summary of Available-For-Sale Securities Recorded in Cash and Cash Equivalents or Marketable Securities	The following table is a summary of available-for-sale securities recorded in cash and cash equivalents or marketable securities in the Company’s consolidated balance sheets as of December 31, 2022 and 2021 (in thousands): December 31, 2022 Amortized Unrealized Unrealized Fair Cash equivalents: U.S. Treasury money market funds $ 38,745 $ — $ — $ 38,745 Marketable securities: U.S. Treasury securities 40,340 — ( 199 ) 40,141 Commercial paper 117,855 2 ( 379 ) 117,478 Corporate debt securities 1,978 — — 1,978 U.S. Government agency bonds 76,610 56 ( 158 ) 76,508 Total $ 275,528 $ 58 $ ( 736 ) $ 274,850 Cash 1,711 Total cash, cash equivalent and marketable securities $ 276,561 December 31, 2021 Amortized Cost Unrealized Unrealized Fair Value Cash equivalents: U.S. Treasury money market funds $ 60,375 $ — $ — $ 60,375 Marketable securities: U.S. Treasury securities 82,204 — ( 98 ) 82,106 Commercial paper 46,678 13 ( 4 ) 46,687 Corporate debt securities 15,486 — ( 5 ) 15,481 U.S. agency bonds 1,200 — ( 1 ) 1,199 Total available-for-sale securities $ 205,943 $ 13 $ ( 108 ) $ 205,848 Cash 2,507 Total cash, cash equivalent and marketable securities $ 208,355
Summary of Gross Unrealized Losses and Fair Value by Major Security Type for Available-For-Sale Securities in Unrealized Loss Position	The following tables display additional information regarding gross unrealized losses and fair value by major security type for available-for-sale securities in an unrealized loss position as of December 31, 2022 and 2021 (in thousands): December 31, 2022 Less than 12 months 12 months or greater Fair Value Unrealized Losses Fair Value Unrealized Losses U.S. Treasury securities $ 33,782 $ ( 196 ) $ 6,359 $ ( 3 ) Commercial paper 112,706 ( 379 ) — — Corporate debt securities 1,978 — — — U.S. agency bonds 33,942 ( 147 ) 5,490 ( 11 ) Total $ 182,408 $ ( 722 ) $ 11,849 $ ( 14 ) December 31, 2021 Less than 12 months 12 months or greater Fair Value Unrealized Losses Fair Value Unrealized Losses U.S. Treasury securities $ 82,106 $ ( 98 ) $ — $ — Commercial paper 13,734 ( 4 ) — — Corporate debt securities 15,481 ( 5 ) — — U.S. agency bonds 1,199 ( 1 ) — — Total $ 112,520 $ ( 108 ) $ — $ —
Summary of Amortized Cost and Estimated Fair Value of Available-for-sale Securities by Contractual Maturity	As of December 31, 2022, the amortized cost and estimated fair value of the Company’s available-for-sale securities by contractual maturity are shown below (in thousands): Amortized Estimated Cost Fair Value Available-for-sale securities maturing in: One year or less $ 263,664 $ 263,001 One to two years 11,864 11,849 Total available-for-sale securities $ 275,528 $ 274,850

Balance Sheet Components (Table

Balance Sheet Components (Tables)	12 Months Ended
	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Property and Equipment, Net	Property and equipment, net consisted of the following as of December 31, 2022 and 2021 (in thousands): December 31, December 31, Leasehold improvements $ 3,366 $ 3,268 Furniture, laboratory and office equipment 4,423 3,423 Computer equipment 244 244 Total property and equipment 8,033 6,935 Less: accumulated depreciation and amortization ( 4,602 ) ( 3,652 ) Property and equipment, net $ 3,431 $ 3,283
Accrued Liabilities	Accrued liabilities consisted of the following as of December 31, 2022 and 2021 (in thousands): December 31, December 31, Accrued preclinical and research costs $ 1,368 $ 1,043 Accrued clinical costs 1,007 1,642 Accrued employee-related costs 3,260 1,970 Accrued professional services 53 231 Other 265 99 Total accrued liabilities $ 5,953 $ 4,985

Lease (Tables)

Lease (Tables)	12 Months Ended
	Dec. 31, 2022
Leases [Abstract]
Details of Right-of-Use Assets and Lease Liabilities	Information related to the Company’s ROU asset and related lease liabilities were as follows (in thousands): For the Year Ended December 31, 2022 2021 2020 Cash paid for operating lease liabilities $ 1,032 $ 1,042 $ 900 Operating lease costs 1,493 1,099 1,099 Variable lease costs 807 765 542 Maturities of lease liabilities as of December 31, 2022 were as follows: Less than 12 months $ 3,767 13 - 24 months 3,890 25 - 36 months 4,025 37 - 48 months 2,418 Total undiscounted lease payments 14,100 Less: imputed interest ( 2,670 ) Total lease liabilities $ 11,430 Operating lease liabilities, current 2,565 Operating lease liabilities, noncurrent 8,865 Total operating lease liabilities $ 11,430

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2022
Debt Disclosure [Abstract]
Schedule of Long-term Debt Balance	The components of the long-term debt balance are as follows: December 31, December 31, Principal loan balance $ 10,000 $ 10,000 Unamortized debt discount and issuance costs ( 342 ) ( 431 ) Cumulative accretion of final fee 176 53 Long-term debt, net $ 9,834 $ 9,622
Schedule of Estimated Future Principal Payments	As of December 31, 2022, the estimated future principal payments due were as follows: Years Ending December 31, 2023 $ — 2024 — 2025 5,217 2026 4,783 Total $ 10,000

Pre-Funded Warrants (Tables)

Pre-Funded Warrants (Tables)	12 Months Ended
	Dec. 31, 2022
Equity [Abstract]
Summary of Pre-Funded Warrants Outstanding	The following table represents a summary of the pre-funded warrants outstanding as of December 31, 2022. Issue Date Classification Exercise price Expiration Date Number of shares underlying February 4, 2020 Equity $ 0.001 February 4, 2040 2,884,615 June 11, 2020 Equity $ 0.001 June 11, 2040 909,091 Total Outstanding 3,793,706

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Summary of Activity under Stock Option Plans and Related Information	The following table summarizes activity under the Company’s stock option plans and related information (in thousands, except share and per share amounts): Number of Weighted Weighted Average Aggregate Outstanding at December 31, 2021 6,945,184 $ 5.95 7.9 $ 77,363 Options granted 3,036,235 $ 12.80 Options exercised ( 189,978 ) $ 3.44 $ 1,504 Options cancelled/forfeited ( 106,631 ) $ 8.02 Outstanding at December 31, 2022 9,684,810 $ 8.12 7.6 $ 15,407 Vested and exercisable at December 31, 2022 5,063,304 $ 6.85 6.7 $ 11,532
Summary of RSU Activity	Number of RSUs Outstanding Weighted Average Grant-Date Fair Price Outstanding as of December 31, 2021 — RSUs granted 439,615 $ 9.81 RSUs vested — $ — RSUs forfeited ( 4,825 ) $ 10.60 Outstanding as of December 31, 2022 434,790 $ 9.80
Stock-Based Compensation Expense Recognized	Total stock-based compensation expense recognized by function was as follows (in thousands): Year Ended December 31, 2022 2021 2020 Research and development $ 6,612 $ 2,955 $ 2,102 General and administrative 7,394 4,641 2,841 Total stock-based compensation expense $ 14,006 $ 7,596 $ 4,943
Fair Value of Employee Stock Options Granted and ESPP Rights to Purchase Common Stock Calculated Using Black Scholes Option Pricing Model with Weighted Average Assumptions	The fair value of the employee stock options granted and the ESPP rights to purchase common stock of the Company is calculated using the Black-Scholes option-pricing model with the following weighted-average assumptions: Options ESPP Rights Year Ended December 31, Year Ended December 31, 2022 2021 2020 2022 2021 2020 Expected term (years) 5.5 - 6.1 5.5 - 6.1 5.5 - 6.0 0.5 0.5 0.5 Expected volatility 84.3 - 88.5 % 85.4 - 88.1 % 83.8 - 91.9 % 85.6 - 114.9 % 64.0 - 77.2 % 101.7 - 114.3 % Risk-free interest rate 1.6 - 4.1 % 0.5 - 1.3 % 0.4 - 1.6 % 1.5 - 4.5 % 0.0 - 0.1 % 0.1 - 0.2 % Expected dividend yield — — — — — —

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Schedule of Domestic and Foreign Components of Net Loss	The following table presents domestic and foreign components of net loss for the periods presented (in thousands): Year Ended December 31, 2022 2021 2020 Domestic $ ( 68,097 ) $ ( 54,581 ) $ ( 41,599 ) Foreign ( 142 ) ( 49 ) ( 143 ) Total $ ( 68,239 ) $ ( 54,630 ) $ ( 41,742 )
Schedule of Effective Tax Rate of Provision for Income Taxes Differs From Federal Statutory Rate	The effective tax rate of the provision for income taxes differs from the federal statutory rate as follows: Year Ended December 31, 2022 2021 2020 Federal statutory income tax rate 21.0 % 21.0 % 21.0 % State taxes, net of federal benefit 1.3 1.3 1.1 Foreign tax rate differential 0.0 0.0 0.0 Permanent differences ( 0.6 ) ( 2.2 ) ( 2.7 ) Research and development credit 2.5 4.0 2.6 Change in valuation allowance ( 24.2 ) ( 24.1 ) ( 22.0 ) Provision for income taxes — % — % — %
Schedule of Components of Deferred Tax Assets and Liabilities	The components of the deferred tax assets and liabilities are as follows (in thousands): Year Ended December 31, 2022 2021 Deferred tax assets Reserves and accruals $ 3,420 $ 2,043 Net operating loss carryforwards 37,939 34,617 Research and development credit carryforwards 7,603 5,127 Lease Liabilities 2,402 929 R&D Capitalization 7,979 — Gross deferred tax assets 59,343 42,716 Valuation allowance ( 56,983 ) ( 41,771 ) Net deferred tax assets 2,360 945 Deferred tax liabilities Property and equipment ( 313 ) ( 375 ) Right-of-use asset ( 2,047 ) ( 570 ) Net deferred tax assets $ — $ —
Reconciliation of Unrecognized Tax Benefits	A reconciliation of the Company’s unrecognized tax benefits for the year ended December 31, 2022, 2021 and 2020 is as follows (in thousands): Year Ended December 31, 2022 2021 Balance at the beginning of the year $ 1,643 $ 868 Decrease related to prior year tax positions ( 187 ) — Increase related to current year tax positions 1,066 775 Balance at the end of the year $ 2,522 $ 1,643

Net Loss per Share (Tables)

Net Loss per Share (Tables)	12 Months Ended
	Dec. 31, 2022
Earnings Per Share [Abstract]
Calculation of Basic and Diluted Net Loss per Share	The following table sets forth the calculation of basic and diluted net loss per share during the periods presented (in thousands, except share and per share data): Year Ended December 31, 2022 2021 2020 Numerator: Net loss $ ( 68,239 ) $ ( 54,630 ) $ ( 41,742 ) Denominator: Weighted-average shares of common stock outstanding 67,368,935 52,759,335 44,004,190 Net loss per share, basic and diluted $ ( 1.01 ) $ ( 1.04 ) $ ( 0.95 )
Anti-dilutive Outstanding Shares of Common Stock Equivalents Excluded from Computation of Diluted Net Loss per Share	The following outstanding shares of common stock equivalents were excluded from the computation of the diluted net loss per share for the periods presented because their effect would have been anti-dilutive: Year Ended December 31, 2022 2021 2020 Options to purchase common stock 9,684,810 6,945,184 4,489,122 Restricted stock units subject to future vesting 434,790 — — Common stock subject to future vesting — — 8,859 Total 10,119,600 6,945,184 4,497,981

Organization and Description _2

Organization and Description of the Business - Additional Information (Details)			1 Months Ended	12 Months Ended
	Jun. 11, 2020 USD ($) $ / shares shares	Feb. 04, 2020 USD ($) $ / shares shares	Jul. 31, 2020 shares	Dec. 31, 2022 USD ($) Segment $ / shares shares	Dec. 31, 2021 USD ($) $ / shares shares	Dec. 31, 2020 USD ($)	Jan. 06, 2023 $ / shares shares	Nov. 30, 2021 USD ($) Tranche
Organization And Description Of Business [Line Items]
Number of operating segments | Segment				1
Accumulated deficit				$ 248,893,000	$ 180,654,000
Issuance of common stock | shares				11,911,699	9,352,359
Weighted average purchase price, per share | $ / shares				$ 10.95	$ 11.13
Pre funded warrants to purchase shares of common stock | shares	909,091	2,884,615		3,793,706
Pre funded warrants exercise price | $ / shares	$ 0.001	$ 0.001		$ 0.001
Net proceeds under at-the-market offering programs				$ 126,542,000	$ 100,970,000	$ 0
Common stock, shares authorized | shares				125,000,000	125,000,000
Preferred stock, shares authorized | shares				10,000,000	10,000,000
Underwritten Public Offering
Organization And Description Of Business [Line Items]
Issuance of common stock | shares	7,590,909	18,965,385	427,707
Pre funded warrants to purchase shares of common stock | shares	909,091	2,884,615
Pre funded warrants exercise price | $ / shares	$ 0.001	$ 0.001
Common stock, shares issued, price per share | $ / shares	5.50	2.60
Warrant issue price per share | $ / shares	$ 5.499	$ 2.599
Net proceeds from the public offering	$ 45,800,000	$ 53,400,000
Commission paid				$ 3,900,000	$ 3,100,000
Underwritten Public Offering | Existing Stockholder, Equal Talent Investments Limited, and one of the Directors
Organization And Description Of Business [Line Items]
Net proceeds from the public offering	$ 8,500,000
Underwritten Public Offering | Existing Stockholder, Morningside Ventures and certain officers and directors
Organization And Description Of Business [Line Items]
Net proceeds from the public offering		$ 10,400,000
ATM Offering Program
Organization And Description Of Business [Line Items]
Net proceeds from the public offering				126,500,000	$ 101,000,000
Subsequent Event
Organization And Description Of Business [Line Items]
Pre funded warrants to purchase shares of common stock | shares							2,236,553
Pre funded warrants exercise price | $ / shares							$ 0.001
Loan and Security Agreement | Oxford Finance LLC
Organization And Description Of Business [Line Items]
Line of credit facility, maximum borrowing capacity								$ 50,000,000
Number of tranches | Tranche								5
Current borrowing capacity				$ 40,000,000
Loan and Security Agreement | Oxford Finance LLC | Tranche One
Organization And Description Of Business [Line Items]
Current borrowing capacity								$ 10,000,000
Minimum
Organization And Description Of Business [Line Items]
Sufficient cash and cash equivalents available period term				12 months

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2022 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Impairment losses	$ 0
Interest charges or penalties related to unrecognized tax benefits	0
Restricted cash	$ 0
Furniture, Laboratory and Office Equipment | Minimum
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives of the assets	5 years
Furniture, Laboratory and Office Equipment | Maximum
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives of the assets	7 years
Computer Equipment
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives of the assets	3 years
Australia
Summary Of Significant Accounting Policies [Line Items]
Concentrations of credit risk	$ 700,000

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Financial Assets Measured at Fair Value on Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial Assets	$ 274,850	$ 205,848
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial Assets	78,886	142,481
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial Assets	195,964	63,367
U.S. Treasury money market funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial Assets	38,745	60,375
U.S. Treasury money market funds | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial Assets	38,745	60,375
U.S. Treasury Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial Assets	40,141	82,106
U.S. Treasury Securities | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial Assets	40,141	82,106
Commercial paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial Assets	117,478	46,687
Commercial paper | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial Assets	117,478	46,687
Corporate debt securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial Assets	1,978	15,481
Corporate debt securities | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial Assets	1,978	15,481
U.S. Government agency bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial Assets	76,508	1,199
U.S. Government agency bonds | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial Assets	$ 76,508	$ 1,199

Available-for-Sale Securities -

Available-for-Sale Securities - Summary of Available-For-Sale Securities Recorded in Cash and Cash Equivalents or Marketable Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total available-for-sale securities, Amortized Cost	$ 275,528
Fair Value	274,850
Fair Value, Measurements, Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total available-for-sale securities, Amortized Cost	275,528	$ 205,943
Unrealized Gains	58	13
Unrealized Losses	(736)	(108)
Fair Value	274,850	205,848
Cash	1,711	2,507
Total cash, cash equivalent and marketable securities	276,561	208,355
Fair Value, Measurements, Recurring | U.S. Treasury money market funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total available-for-sale securities, Amortized Cost	38,745	60,375
Fair Value	38,745	60,375
Fair Value, Measurements, Recurring | U.S. Treasury Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total available-for-sale securities, Amortized Cost	40,340	82,204
Unrealized Losses	(199)	(98)
Fair Value	40,141	82,106
Fair Value, Measurements, Recurring | Commercial paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total available-for-sale securities, Amortized Cost	117,855	46,678
Unrealized Gains	2	13
Unrealized Losses	(379)	(4)
Fair Value	117,478	46,687
Fair Value, Measurements, Recurring | Corporate debt securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total available-for-sale securities, Amortized Cost	1,978	15,486
Unrealized Losses		(5)
Fair Value	1,978	15,481
Fair Value, Measurements, Recurring | U.S. agency bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total available-for-sale securities, Amortized Cost	76,610	1,200
Unrealized Gains	56
Unrealized Losses	(158)	(1)
Fair Value	$ 76,508	$ 1,199

Available-for-Sale Securities_2

Available-for-Sale Securities - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Investments, Debt and Equity Securities [Abstract]
Allowance for credit losses on securities in unrealized loss position	$ 0	$ 0
Sale of available-for-sale securities	$ 0

Available-for-Sale Securities_3

Available-for-Sale Securities - Summary of Gross Unrealized Losses and Fair Value by Major Security Type for Available-For-Sale Securities in Unrealized Loss Position (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value, Less than 12 months	$ 182,408	$ 112,520
Unrealized Losses, Less than 12 months	(722)	(108)
Fair Value, 12 months or greater	11,849
Unrealized Losses, 12 months or greater	(14)
U.S. Treasury Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value, Less than 12 months	33,782	82,106
Unrealized Losses, Less than 12 months	(196)	(98)
Fair Value, 12 months or greater	6,359
Unrealized Losses, 12 months or greater	(3)
Commercial paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value, Less than 12 months	112,706	13,734
Unrealized Losses, Less than 12 months	(379)	(4)
Corporate debt securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value, Less than 12 months	1,978	15,481
Unrealized Losses, Less than 12 months		(5)
U.S. agency bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value, Less than 12 months	33,942	1,199
Unrealized Losses, Less than 12 months	(147)	$ (1)
Fair Value, 12 months or greater	5,490
Unrealized Losses, 12 months or greater	$ (11)

Available-for-Sale Securities_4

Available-for-Sale Securities - Summary of Amortized Cost and Estimated Fair Value of Available-for-sale Securities by Contractual Maturity (Details) $ in Thousands	Dec. 31, 2022 USD ($)
Available-for-sale securities maturing, Amortized Cost:
In one year or less, Amortized Cost	$ 263,664
In one to two years, Amortized Cost	11,864
Total available-for-sale securities, Amortized Cost	275,528
Available-for-sale securities maturing, Estimated Fair Value:
In one year or less, Estimated Fair Value	263,001
In one to two years, Estimated Fair Value	11,849
Total available-for-sale securities, Estimated Fair Value	$ 274,850

Balance Sheet Components - Prop

Balance Sheet Components - Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Property Plant And Equipment [Line Items]
Total property and equipment	$ 8,033	$ 6,935
Less accumulated depreciation and amortization	(4,602)	(3,652)
Property and equipment, net	3,431	3,283
Leasehold Improvements
Property Plant And Equipment [Line Items]
Total property and equipment	3,366	3,268
Furniture, Laboratory and Office Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	4,423	3,423
Computer Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	$ 244	$ 244

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Depreciation expense	$ 1	$ 0.9	$ 0.9

Balance Sheet Components - Accr

Balance Sheet Components - Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accrued preclinical and research costs	$ 1,368	$ 1,043
Accrued clinical costs	1,007	1,642
Accrued employee-related costs	3,260	1,970
Accrued professional services	53	231
Other	265	99
Total accrued liabilities	$ 5,953	$ 4,985

Lease - Additional Information

Lease - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Nov. 30, 2022
Operating lease existence of option to extend [true false]			true
Operating lease, option to extend	The operating lease agreement has one option to extend the lease term for a period of five years at the fair market rate at the time of the extension.
Operating lease, renewal term	5 years
Weighted average remaining lease term	3 years 6 months 29 days
Operating lease liability, weighted average discount rate	11.67%
Rent expense	$ 1,500	$ 1,100	$ 1,100
Variable lease costs	807	765	$ 542
Operating lease liability	11,430
Operating lease right-of-use asset	$ 9,741	$ 2,714
South San Francisco, California [Member]
Operating lease, option to extend	July 31, 2026
Operating lease liability				$ 8,000
Operating lease right-of-use asset				$ 8,000

Lease - Details of Right-of-Use

Lease - Details of Right-of-Use Assets and Lease Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Lessee Disclosure [Abstract]
Cash paid for operating lease liabilities	$ 1,032	$ 1,042	$ 900
Operating lease costs	1,493	1,099	1,099
Variable lease costs	807	765	$ 542
Less than 12 months	3,767
13 - 24 months	3,890
25 - 36 months	4,025
37 - 48 months	2,418
Total undiscounted lease payments	14,100
Less: imputed interest	(2,670)
Total lease liabilities	11,430
Operating lease liabilities, current	2,565	1,199
Operating lease liabilities, noncurrent	8,865	$ 3,223
Total operating lease liabilities	$ 11,430

Debt - Additional Information (

Debt - Additional Information (Details) - Loan and Security Agreement - Oxford Finance LLC	1 Months Ended	12 Months Ended
	Nov. 30, 2021 USD ($) Tranche	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 50,000,000
Number of tranches | Tranche	5
Current borrowing capacity		$ 40,000,000
Line of credit facility, Maturity period	Nov. 01, 2026
Line of credit facility frequency of payments		monthly interest-only payments
Line of credit facility, extension period	1 year
Final payment fee percentage	6.50%
Interest expense		$ 1,200,000	$ 200,000
Effective interest rate percentage	11%
Minimum
Debt Instrument [Line Items]
Prepayment fee percentage	1%
Maximum
Debt Instrument [Line Items]
Prepayment fee percentage	2%
Tranche One
Debt Instrument [Line Items]
Current borrowing capacity	$ 10,000,000
Tranche Two
Debt Instrument [Line Items]
Current borrowing capacity	$ 20,000,000
Equal To Sum Of A | Floor Rate
Debt Instrument [Line Items]
Line of credit facility, additional interest rate	0.08%
Equal To Sum Of B
Debt Instrument [Line Items]
Line of credit facility, interest rate	7.87%

Debt - Schedule of Long-term De

Debt - Schedule of Long-term Debt Balance (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Debt Disclosure [Abstract]
Principal loan balance	$ 10,000	$ 10,000
Unamortized debt discount and issuance costs	(342)	(431)
Cumulative accretion of final fee	176	53
Long-term debt, net	$ 9,834	$ 9,622

Debt - Schedule of Estimated Fu

Debt - Schedule of Estimated Future Principal Payments (Details) $ in Thousands	Dec. 31, 2022 USD ($)
Debt Disclosure [Abstract]
2025	$ 5,217
2026	4,783
Total	$ 10,000

Pre-Funded Warrants - Additiona

Pre-Funded Warrants - Additional Information (Details) - $ / shares	Jun. 11, 2020	Feb. 04, 2020	Jan. 06, 2023	Dec. 31, 2022
Class Of Warrant Or Right [Line Items]
Pre funded warrants to purchase shares of common stock	909,091	2,884,615		3,793,706
Pre funded warrants exercise price	$ 0.001	$ 0.001		$ 0.001
Pre-funded warrants, term				20 years
Maximum ownership percentage, not to exceed upon exercise of warrants				4.99%
Maximum ownership percentage, increase or decrease upon prior notice				19.99%
Pre-funded warrants exercised				0
Subsequent Event
Class Of Warrant Or Right [Line Items]
Pre funded warrants to purchase shares of common stock			2,236,553
Pre funded warrants exercise price			$ 0.001
February Offering
Class Of Warrant Or Right [Line Items]
Pre funded warrants to purchase shares of common stock		2,884,615
June Offering
Class Of Warrant Or Right [Line Items]
Pre funded warrants to purchase shares of common stock	909,091
Underwritten Public Offering
Class Of Warrant Or Right [Line Items]
Pre funded warrants to purchase shares of common stock	909,091	2,884,615
Warrant issue price per share	$ 5.499	$ 2.599
Pre funded warrants exercise price	$ 0.001	$ 0.001

Pre-Funded Warrants - Summary o

Pre-Funded Warrants - Summary of Pre-Funded Warrants Outstanding (Details) - $ / shares	Jun. 11, 2020	Feb. 04, 2020	Dec. 31, 2022
Stockholders' Equity Note [Abstract]
Issue Date	Jun. 11, 2020	Feb. 04, 2020
Exercise Price	$ 0.001	$ 0.001	$ 0.001
Expiration Date	Jun. 11, 2040	Feb. 04, 2040
Number of shares underlying warrants	909,091	2,884,615	3,793,706

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Jan. 01, 2022	Jun. 30, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options shares outstanding	9,684,810	6,945,184
Common stock, shares issued	68,493,429	56,259,747
Aggregate intrinsic value of exercised stock options	$ 1,504,000	$ 2,100,000
Payments of dividends of common stock	$ 0
Expected dividend yield	0%	0%	0%
Employee options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock-based compensation cost	$ 33,100,000
Estimated weighted average amortization period	2 years 6 months
Employee options | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term	6 years 1 month 6 days	6 years 1 month 6 days	6 years
Employee options | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term	5 years 6 months	5 years 6 months	5 years 6 months
ESPP
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term	6 months	6 months	6 months
2022 Stock Inducement Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options shares outstanding	624,000
Shares granted	3,000,000
shares available for future issuance	2,376,000
2018 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options shares outstanding	7,532,708
shares available for future issuance	782,397
additional shares authorized for future issuance				2,812,987
Number of shares will increase automatically through every year on specified date	--01-01
Number of shares increase automatically continuing through maximum period	beginning on January 1, 2019 and continuing through and including January 1, 2028
Weighted average grant date fair value of options granted	$ 9.81	$ 4.20
2018 Equity Incentive Plan | Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Maximum number of shares authorized available for issuance	1,600,692
Increase in number of shares reserved for issuance as percentage of total number of shares of capital stock outstanding on last date of preceding calendar year	5%
2018 Equity Incentive Plan | Maximum | Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Maximum number of shares authorized available for issuance	4,000,000
2018 Equity Incentive Plan | Incentive Stock Options | Maximum | Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Maximum number of shares issued upon exercise of incentive stock options	12,500,000
2018 Equity Incentive Plan | RSU Member
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Option grant vesting period	3 years
2015 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Option grant vesting period	4 years
Options to purchase of common stock outstanding	1,528,102
2015 Equity Incentive Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options granted expiry period	10 years
2018 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
shares available for future issuance				375,000
2018 Employee Stock Purchase Plan | Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
shares available for future issuance	954,987				200,000
Common stock, shares issued	378,237
Authorized an offering beginning period	Nov. 16, 2018
Authorized an offering ending period	May 15, 2019
Authorized an additional offering beginning period	Nov. 16, 2022
2018 Employee Stock Purchase Plan | Maximum | Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of annual increase in number of common stock shares	1%
Annual increase in number of common stock shares	375,000
Option price per share of common stock at fair market value	85%

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Activity under Stock Option Plans and Related Information (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Share-Based Payment Arrangement [Abstract]
Number of options outstanding, Outstanding, Beginning balance	6,945,184
Number of options outstanding, Options granted	3,036,235
Number of options outstanding, Options exercised	(189,978)
Number of options outstanding, Options cancelled/forfeited	(106,631)
Number of options outstanding, Outstanding, Ending balance	9,684,810	6,945,184
Number of options outstanding, options vested and exercisable	5,063,304
Weighted average exercise price, Outstanding, Beginning balance	$ 5.95
Weighted average exercise price, Options granted	12.80
Weighted average exercise price, Options exercised	3.44
Weighted average exercise price, Options cancelled/forfeited	8.02
Weighted average exercise price, Outstanding, Ending balance	8.12	$ 5.95
Weighted average exercise price, options vested and exercisable	$ 6.85
Weighted average remaining contractual term, (Years) Outstanding, Beginning balance	7 years 7 months 6 days	7 years 10 months 24 days
Weighted average remaining contractual term, (Years) options vested and exercisable	6 years 8 months 12 days
Aggregate intrinsic value, Outstanding, Beginning balance	$ 77,363
Aggregate intrinsic value, Options exercised	1,504	$ 2,100
Aggregate intrinsic value, Outstanding, Ending balance	15,407	$ 77,363
Aggregate intrinsic value, options vested and exercisable	$ 11,532

Stock Based Compensation - Summ

Stock Based Compensation - Summary of RSU Activity (Details)	12 Months Ended
	Dec. 31, 2022 $ / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Weighted average exercise price, Options cancelled/forfeited	$ 8.02
Weighted average exercise price, Outstanding, Ending balance	$ 8.12
RSU Member | 2018 Equity Incentive Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of shares, granted | shares	439,615
Number of shares, vested | shares	0
Number of shares, forfeited | shares	(4,825)
Number of shares outstanding, ending balance | shares	434,790
Weighted average exercise price, granted	$ 9.81
Weighted average exercise price, Options cancelled/forfeited	10.60
Weighted average exercise price, Outstanding, Ending balance	$ 9.80

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock-Based Compensation Expense Recognized (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 14,006	$ 7,596	$ 4,943
Research and Development Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	6,612	2,955	2,102
General and Administrative Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 7,394	$ 4,641	$ 2,841

Stock-Based Compensation - Fair

Stock-Based Compensation - Fair Value of Employee Stock Options Granted and ESPP Rights to Purchase Common Stock Calculated Using Black Scholes Option Pricing Model with Weighted Average Assumptions (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Employee options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected volatility, Minimum	84.30%	85.40%	83.80%
Expected volatility, Maximum	88.50%	88.10%	91.90%
Risk-free interest rate, Minimum	1.60%	0.50%	0.40%
Risk-free interest rate, Maximum	4.10%	1.30%	1.60%
ESPP Rights
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (years)	6 months	6 months	6 months
Expected volatility, Minimum	85.60%	64%	101.70%
Expected volatility, Maximum	114.90%	77.20%	114.30%
Risk-free interest rate, Minimum	1.50%	0%	0.10%
Risk-free interest rate, Maximum	4.50%	0.10%	0.20%
Minimum | Employee options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (years)	5 years 6 months	5 years 6 months	5 years 6 months
Maximum | Employee options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (years)	6 years 1 month 6 days	6 years 1 month 6 days	6 years

License Agreement - Additional

License Agreement - Additional Information (Details)	1 Months Ended
	Jun. 30, 2015 USD ($)
License Agreement | Amgen, Inc
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Maximum future payments upon achievement of certain development and commercial milestones	$ 172,500,000

Defined Contribution Plan - Add

Defined Contribution Plan - Additional Information (Details) - Savings and Investment Plan - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Contribution Plan Disclosure [Line Items]
Employees contributions amount up to lesser of pre-tax compensation	$ 56,000
Percentage of employees contributions amount up to lesser of pre-tax compensation	100%
Employer match of per contribution towards participants contribution	$ 1
Participants of plan per contribution	1
Employer incurred matching contribution expenses	$ 600,000	$ 400,000	$ 300,000
Maximum
Defined Contribution Plan Disclosure [Line Items]
Employer match of employees contributions in amount in percentage	4%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	1 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Taxes Disclosure [Line Items]
Provision for income taxes		$ 0	$ 0	$ 0
Research and development tax credit utilized against employer's portion of payroll tax	$ 250,000
Research and development tax credit utilized as reduction of payroll expenses		79,000	325,000	373,000
Valuation allowance increased		15,200,000	12,400,000	9,200,000
Benefit for deferred tax assets		0
Unrecognized tax benefits		2,522,000	$ 1,643,000	$ 868,000
Liability related to uncertain tax positions		0
Accrued interest and penalties related to gross unrecognized tax benefits		0
Australian Taxation Office
Income Taxes Disclosure [Line Items]
Net operating loss (NOL) carryforwards		1,900,000
Federal
Income Taxes Disclosure [Line Items]
Net operating loss (NOL) carryforwards		$ 172,200,000
Net operating loss carryforwards expiration start year		2035
Net operating loss (NOL) carryforwards indefinite		$ 150,100,000
Federal | Research and Development
Income Taxes Disclosure [Line Items]
Tax credit carryforward expiration start year		2035
Tax credit carryforward		$ 7,000,000
State
Income Taxes Disclosure [Line Items]
Net operating loss (NOL) carryforwards		$ 17,400,000
Net operating loss carryforwards expiration start year		2035
State | Research and Development
Income Taxes Disclosure [Line Items]
Tax credit carryforward		$ 3,700,000

Income Taxes - Schedule of Dome

Income Taxes - Schedule of Domestic and Foreign Components of Net Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Loss Carryforwards [Line Items]
Net loss	$ (68,239)	$ (54,630)	$ (41,742)
Domestic
Operating Loss Carryforwards [Line Items]
Net loss	(68,097)	(54,581)	(41,599)
Foreign
Operating Loss Carryforwards [Line Items]
Net loss	$ (142)	$ (49)	$ (143)

Income Taxes - Schedule of Effe

Income Taxes - Schedule of Effective Tax Rate of Provision for Income Taxes Differs From Federal Statutory Rate (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Federal statutory income tax rate	21%	21%	21%
State taxes, net of federal benefit	1.30%	1.30%	1.10%
Foreign tax rate differential	0%	0%	0%
Permanent differences	(0.60%)	(2.20%)	(2.70%)
Research and development credit	2.50%	4%	2.60%
Change in valuation allowance	(24.20%)	(24.10%)	(22.00%)

Income Taxes - Schedule of Comp

Income Taxes - Schedule of Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets
Reserves and accruals	$ 3,420	$ 2,043
Net operating loss carryforwards	37,939	34,617
Research and development credit carryforwards	7,603	5,127
Lease Liabilities	2,402	929
R&D Capitalization	7,979
Gross deferred tax assets	59,343	42,716
Valuation allowance	(56,983)	(41,771)
Net deferred tax assets	2,360	945
Deferred tax liabilities
Property and equipment	(313)	(375)
Right-of-use asset	$ (2,047)	$ (570)

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Components of Deferred Tax Assets and Liabilities [Abstract]
Balance at the beginning of the year	$ 1,643	$ 868
Decrease related to prior year tax positions	(187)
Increase related to current year tax positions	1,066	775
Balance at the end of the year	$ 2,522	$ 1,643

Net Loss Per Share - Calculatio

Net Loss Per Share - Calculation of Basic and Diluted Net Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Numerator:
Net loss	$ (68,239)	$ (54,630)	$ (41,742)
Denominator:
Weighted-average shares of common stock outstanding	67,368,935	52,759,335	44,004,190
Net loss per common share, Basic	$ (1.01)	$ (1.04)	$ (0.95)
Net loss per common share, Diluted	$ (1.01)	$ (1.04)	$ (0.95)

Net Loss Per Share - Anti-dilut

Net Loss Per Share - Anti-dilutive Outstanding Shares of Common Stock Equivalents Excluded from Computation of Diluted Net Loss per Share (Details) - shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net loss per share	10,119,600	6,945,184	4,497,981
Options to Purchase Common Stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net loss per share	9,684,810	6,945,184	4,489,122
Restricted stock units subject to future vesting [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net loss per share	434,790
Common stock subject to future vesting [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net loss per share			8,859

Selected Quarterly Financial In

Selected Quarterly Financial Information (Unaudited) - Schedule of Selected Quarterly Financial Information (Unaudited) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Operating expenses	$ 71,162	$ 54,659	$ 42,950
Net loss	$ (68,239)	$ (54,630)	$ (41,742)