0001628280-26-033104 | 10-Q | XBRL Viewer

Balance Sheet Components

3 Months Ended

Mar. 31, 2026

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets consisted of the following (in thousands):


	March 31, 2026		December 31, 2025
Unbilled receivable from Everest, current (Note 8)	$	—	$	1,741
Deposits for operating lease	674		674
Insurance	226		463
Interest receivable	206		184
Licenses, dues and subscriptions	38		72
Others	190		200
Total prepaid expenses and other current assets	$	1,334	$	3,334

Property and Equipment, Net

Property and equipment, net consisted of the following (in thousands):


	March 31, 2026		December 31, 2025
Leasehold improvements	$	—	$	3,268
Computer equipment	—		184
Total property and equipment	—		3,452
Less: accumulated depreciation and amortization	—		(3,286)
Property and equipment, net	$	—	$	166

Depreciation expense was $47 thousand for the three months ended March 31, 2026, compared to $0.3 million for the three months ended March 31, 2025.

As a result of restructuring, the Company disposed of all property and equipment during the three months ended March 31, 2026.

Accrued and Other Current Liabilities

Accrued liabilities consisted of the following (in thousands):


	March 31, 2026		December 31, 2025
Accrued preclinical and research costs	$	25	$	1,686
Accrued severance related costs	179		1,556
Accrued clinical costs	4		93
Accrued employee-related costs	—		66
Accrued professional services	850		42
Others	77		298
Total accrued liabilities	$	1,135	$	3,741

Lease - Additional Information (Details) - USD ($)		1 Months Ended	3 Months Ended	12 Months Ended
Lease - Additional Information (Details) - USD ($)	Apr. 01, 2026	Jun. 30, 2024	Mar. 31, 2026	Dec. 31, 2023	Dec. 31, 2025	Nov. 30, 2022
Lessee, Lease, Description [Line Items]
Operating lease right-of-use asset			$ 436,000		$ 749,000
Operating lease liability			1,354,000
Impairment charge		$ 1,500,000		$ 2,700,000
Sublease income		$ 0
Lease liability to be paid			1,388,000
Lease payment to landlord			$ 972,000
Subsequent Event
Lessee, Lease, Description [Line Items]
Lease liability to be paid	$ 2,000,000.0
Lease payment to landlord	1,300,000
Surrendered security deposit	$ 700,000
South San Francisco, California
Lessee, Lease, Description [Line Items]
Operating lease right-of-use asset						$ 8,000,000.0
Operating lease liability						$ 8,000,000.0

Everest Collaboration	3 Months Ended
Everest Collaboration	Mar. 31, 2026
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Everest Collaboration	Everest Collaboration In September 2023, the Company entered into a Collaboration and License Agreement (the “Everest License Agreement”) with Everest Medicines II (HK) Limited (“Everest”) pursuant to which, among other things, the Company granted to Everest an exclusive license to develop and commercialize one or more products containing the Company’s proprietary compound, zetomipzomib (the “Products”), in the licensed field in the Greater China region (Mainland China, Taiwan, Hong Kong and Macau), South Korea, Singapore, Malaysia, Thailand, Indonesia, Vietnam and the Philippines (the “Territory”). The licensed field includes all uses other than the diagnosis or treatment in humans of cancerous or pre-cancerous diseases or conditions. During the PALIZADE trial, Everest contributed their local regulatory and clinical trial expertise and were responsible for study costs in the Territory. Everest Medicines Limited is also a party to the Everest License Agreement solely for limited purposes, including to guarantee the performance by Everest of its obligations under the Everest License Agreement. Under the terms of the Everest License Agreement, the Company received a one-time, irrecoverable, non-refundable and non-creditable upfront payment of $7.0 million in October 2023 and is entitled to receive certain variable payments for manufacturing supply services and milestone payments upon achievement of certain development, regulatory and commercial milestone events, for total potential milestone payments of up to $125.5 million. In addition, Everest will pay to the Company tiered royalties on the net sales of the Products in the Territory during the term of the Everest License Agreement ranging from the single digit to the low-teens, subject to certain reductions for patent expiration, generic competition and payments for licenses to third-party patents. The term of the Everest License Agreement will continue on a market-by-market basis until expiration of the relevant royalty term of the Products, unless terminated earlier. Everest has the right to terminate the Everest License Agreement for convenience at any time following the October 2024 termination of the PALIZADE clinical trial. The Company may terminate the Everest License Agreement if Everest challenges the Company’s patents or fails to perform any development or commercialization activities for a continuous period of more than twelve (12) months, subject to certain exceptions. In addition, either party may terminate the Everest License Agreement for the other party’s uncured breach or insolvency, and the Everest License Agreement will automatically terminate in the event of termination of the Company’s exclusive license agreement with Onyx Therapeutics, Inc. Under the terms of the Everest License Agreement, at the election of Everest, the Company may manufacture and provide clinical supply to Everest to use in development and commercialization in the Territory at the fully burdened manufacturing cost plus specified margins, as defined within the Everest License Agreement. Certain of these provisions were determined to be options to acquire additional goods or services at a price that approximates the stand-alone selling price for that good or service and therefore do not represent material rights, or separate performance obligations, within the context of the Everest License Agreement. The Company evaluated the Everest License Agreement and determined it was within the scope of ASC 606. The transaction price was determined to consist of the upfront payment of $7.0 million. License of Intellectual Property. The license to the Company’s intellectual property and associated know-how represents a distinct performance obligation. The license and associated know-how was transferred to Everest in the third quarter of 2023 to satisfy this performance obligation. The Company allocated the full transaction price to the license of the Company’s intellectual property and accordingly recognized collaboration revenue of $7.0 million in 2023. Milestone Payments. The potential development, regulatory and commercial milestone payments are paid upon achievement of certain milestones as defined in the Everest License Agreement. It was determined that their achievement is highly dependent on factors outside of the Company’s control. These payments have been fully constrained until the Company concludes that achievement of the milestone is probable and that recognition of revenue related to the milestone will not result in a significant reversal in amounts recognized in future periods and, as such, have been excluded from the transaction price. At the end of each subsequent reporting period, the Company will re-evaluate the probability of achievement of each milestone and any related constraint and, if necessary, adjust its estimate of the overall transaction price. As of March 31, 2026, the Company has not recognized any revenue associated with development, regulatory and commercial milestones. Royalties. Any consideration related to royalties will be recognized if and when the related sales occur, as they were determined to relate predominantly to the license granted to Everest and, therefore, have also been excluded from the transaction price. No royalty revenue was recognized as of March 31, 2026. In July 2024, the Company amended the Everest License Agreement to modify a development milestone and adjust certain payment terms relating to Everest’s responsibility for PALIZADE study costs in the Territory. As of March 31, 2026, there was no unbilled receivable. In connection with the cost-sharing arrangement with Everest, no contra research and development expense was recognized for the three months ended March 31, 2026, and 2025, respectively.

Segment Reporting - Additional Information (Details)	3 Months Ended
Segment Reporting - Additional Information (Details)	Mar. 31, 2026 segment
Segment Reporting [Abstract]
Number of operating segments	1
Number of reportable segments	1

Stockholders' Equity	3 Months Ended
Stockholders' Equity	Mar. 31, 2026
Equity [Abstract]
Stockholders' Equity	Stockholders' Equity Rights Plan On October 17, 2024, the Company’s board of directors adopted a limited duration stockholder rights plan (the “Rights Plan”), effective immediately, and declared a dividend of one preferred share purchase right (a “Right”) for each outstanding share of the Company’s common stock as of the close of business on October 28, 2024, the record date. The Rights are exercisable only if a person or group (an “Acquiring Person”) acquires or launches a tender or exchange offer to acquire beneficial ownership (which includes certain synthetic equity interests) of 10% or more of the Company’s outstanding common stock (15% in the case of a passive institutional investor as described in the Rights Plan). Once the Rights become exercisable, each Right will entitle its holder (other than any Acquiring Person, whose Rights will become void) to purchase, for $71.60, one one-hundredth of a share of the Company’s newly designated Series A Junior Participating Preferred Stock, par value $0.001 per share (each, a “Preferred Share” and collectively, the “Preferred Shares”). The description and terms of the Rights Plan are set forth in the Rights Agreement (defined below). The terms of the Preferred Shares are set forth in a Certificate of Designation filed with the Secretary of State of Delaware on October 17, 2024. On October 16, 2025, the Company entered into Amendment No. 2 (the “Amendment 2”) to the Rights Agreement, dated as of October 17, 2024, as amended on December 3, 2024, by and between the Company and Computershare Trust Company, N.A., as rights agent (as amended, the “Rights Agreement”) to extend the duration of the Rights Plan. The Rights Plan, as amended, will automatically expire on the day following the certification of the voting results of the Company’s 2026 annual meeting of stockholders or, if at such meeting the Company’s stockholders approve or ratify the Rights Agreement, the day following the certification of the voting results of the Company’s 2027 annual meeting, unless the Rights are earlier redeemed or exchanged by the Company. The Rights Agreement otherwise remains unmodified and in full force in accordance with its terms. On March 30, 2026, the Company entered into Amendment No. 3 (the “Amendment 3”) to that certain Rights Agreement, dated October 17, 2024 by and between the Company and Computershare Trust Company, N.A., as amended on December 3, 2024, and as further amended on October 16, 2025. As a result of the Amendment 3, Parent and its subsidiaries and affiliates shall not be deemed an “Acquiring Person,” by virtue of (i) the execution of, or their entry into, the Merger Agreement, (ii) the execution of, or their entry into, any other contract or instrument in connection with the Merger Agreement, or (iii) their acquisition of, or their right to acquire, beneficial ownership of the Company’s securities as a result of their execution of the Merger Agreement. The Amendment 3 will terminate upon the termination of the Merger Agreement for any reason. Additionally, Amendment 3 provides that the Rights (as defined in the Rights Agreement) and the Rights Agreement itself will terminate and expire immediately prior to the effective time of the Merger.

- Definition

The entire disclosure for equity.

+ References

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+ Details

Stockholders' Equity (Details)	Oct. 17, 2024 $ / shares shares	Mar. 31, 2026 $ / shares	Dec. 31, 2025 $ / shares
Class Of Warrant Or Right [Line Items]
Purchase price (in dollars per share)	$ 71.60
Preferred stock, par value (in dollars per share)		$ 0.001	$ 0.001
Series A Junior Participating Preferred Stock
Class Of Warrant Or Right [Line Items]
Preferred stock, convertible, conversion ratio	0.01
Preferred stock, par value (in dollars per share)	$ 0.001
Stockholder Rights Plan
Class Of Warrant Or Right [Line Items]
Preferred dividend (in shares) \| shares	1
Beneficial ownership acquired (as a percent)	10.00%
Passive Institutional Investor
Class Of Warrant Or Right [Line Items]
Beneficial ownership acquired (as a percent)	15.00%

Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2026

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):


	March 31, 2026
	Total		Level 1		Level 2		Level 3
Financial Assets:
Cash equivalents:
U.S. Treasury money market funds	$	66,229	$	66,229	$	—	$	—
Total	$	66,229	$	66,229	$	—	$	—


	December 31, 2025
	Total		Level 1		Level 2		Level 3
Financial Assets:
Cash equivalents:
U.S. Treasury money market funds	$	71,878	$	71,878	$	—	$	—
Total	$	71,878	$	71,878	$	—	$	—

Net Loss Per Share (Tables)

3 Months Ended

Mar. 31, 2026

Earnings Per Share [Abstract]

Summary of 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):


	Three Months Ended March 31,
	2026		2025
Numerator:
Net loss	$	(5,756)	$	(16,556)
Denominator:
Weighted-average shares of common stock outstanding	7,343,909		7,305,658
Net loss per share, basic and diluted	$	(0.78)	$	(2.27)

Summary of 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:


	Three Months Ended March 31,
	2026	2025
Stock options to purchase common stock	1,233,867	2,035,773
Restricted stock units subject to future vesting	—	8,451
Total	1,233,867	2,044,224

Restructuring and Impairment Charges (Tables)

3 Months Ended

Mar. 31, 2026

Restructuring and Related Activities [Abstract]

Summary of Restructuring and Impairment Charges

Restructuring and impairment charges, recorded in the Condensed Consolidated Statement of Operations are presented in the table below (in thousands):


	Three Months Ended March 31,
	2026		2025
Severance and related benefit costs	$	493	$	—
Asset impairments	119		—
Total	$	612	$	—

Summary of Accrual Activity and Payments Relating to Restructuring and Impairment Charge

The following table illustrates the accrual activity and payments relating to restructuring and impairment charges (in thousands):


	Severance and related benefit costs		Asset impairments		Total
Balance as of January 1, 2025	$	—	$	—	$	—
Restructuring charges	5,741		1,096		6,837
Cash payments made	(4,185)		—		(4,185)
Non-cash charges	—		(1,096)		(1,096)
Balance as of December 31, 2025	$	1,556	$	—	$	1,556
Restructuring charges	493		119		612
Cash payments made	(1,870)		—		(1,870)
Non-cash charges	—		(119)		(119)
Balance as of March 31, 2026	$	179	$	—	$	179

Stock-Based Compensation - Summary of RSU Activity (Details) - Restricted Stock Units (RSUs) - 2018 Equity Incentive Plan	3 Months Ended
	Mar. 31, 2026 $ / shares shares
Number of RSUs Outstanding
Outstanding, beginning balance (in shares) \| shares	497
RSUs vested (in shares) \| shares	(497)
Outstanding, ending balance (in shares) \| shares	0
Weighted Average Grant-Date Fair Price
Outstanding, beginning balance (in dollars per share) \| $ / shares	$ 68.40
RSUs vested (in dollars per share) \| $ / shares	68.40
Outstanding, ending balance (in dollars per share) \| $ / shares	$ 0

Stock-Based Compensation - Additional Information (Details) - USD ($)	1 Months Ended	3 Months Ended
	Jun. 30, 2018	Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025	Jul. 24, 2023	Apr. 30, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options shares outstanding (in shares)		1,233,867		1,647,096
Common stock, shares issued (in shares)		7,374,375		7,331,739
Compensation expense related to the unvested option		$ 100,000
Options granted (in shares)		0
Aggregate intrinsic value, options exercised		$ 28,000
Payments of dividends of common stock		$ 0
Expected dividend yield (as a percent)		0.00%	0.00%
Share-Based Payment Arrangement, Tranche One
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
RSUs vesting tranches (as a percent)		33.00%
Share-Based Payment Arrangement, Tranche Two
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
RSUs vesting tranches (as a percent)		33.00%
Share-Based Payment Arrangement, Tranche Three
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
RSUs vesting tranches (as a percent)		33.00%
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, granted (in shares)		0
Performance-Based Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense		$ 0	$ 300,000
Share-Based Payment Arrangement, Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock-based compensation cost		$ 2,600,000
Estimated weighted average amortization period (in years)		1 year 10 months 24 days
Employee Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Incremental cost		$ 49,000	$ 100,000
Look back period (in months)		6 months
2022 Stock Inducement Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares granted (in shares)						300,000
Stock options shares outstanding (in shares)		4,419
Shares available for future issuance (in shares)		295,581
2018 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options shares outstanding (in shares)		1,112,830
Shares available for future issuance (in shares)		779,477
Number of shares will increase automatically through every year on specified date		--01-01
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 (in shares)	160,069
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		5.00%
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 (in shares)	400,000
2018 Equity Incentive Plan \| Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options shares outstanding (in shares)		0
Option grant vesting period (in years)		3 years
2018 Equity Incentive Plan \| Incentive Stock Options \| COMMON STOCK
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Maximum number of shares issued upon exercise of incentive stock options (in shares)		1,250,000
2015 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Option grant vesting period (in years)		4 years
Options to purchase of common stock outstanding (in shares)		116,618
2015 Equity Incentive Plan \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options granted expiry period (in years)		10 years
2018 Employee Stock Purchase Plan \| COMMON STOCK
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available for future issuance (in shares)	20,000	40,214
Additional shares available for future issuance (in shares)				0
Common stock, shares issued (in shares)		92,996
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		1.00%
Annual increase in number of common stock shares (in shares)	37,500
Option price per share of common stock at fair market value		85.00%
2018 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Modified exercise price (in dollars per share)					$ 22.80

Income Taxes	3 Months Ended
Income Taxes	Mar. 31, 2026
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes No provision for income taxes was recorded for the three months ended March 31, 2026 and 2025. The Company has maintained a full valuation allowance against its net deferred tax assets as the Company believes it is not more likely than not that the benefit will be realized. On July 4, 2025, the One Big Beautiful Bill Act (“OBBBA”) was enacted into law in the United States. The OBBBA includes significant tax provisions, such as the permanent extension of certain expiring provisions of the Tax Cuts and Jobs Act, modifications to certain international tax framework and the restoration of certain business provisions. The legislation has multiple effective dates, with certain provisions effective in 2025 and others implemented through 2027. The Company evaluated the impact of the OBBBA and determined that it did not have a material impact on the Company’s condensed consolidated financial statements for the three months ended March 31, 2026.

- Definition

The entire disclosure for income tax.

+ References

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+ Details

Summary of Significant Accounting Policies (Policies)	3 Months Ended
Summary of Significant Accounting Policies (Policies)	Mar. 31, 2026
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation and Consolidation The condensed 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 former wholly owned Australian subsidiary, Kezar Life Sciences Australia Pty Ltd., a proprietary company limited by shares, which was dissolved as of September 29, 2025. All intercompany balances and transactions have been eliminated upon consolidation. The condensed consolidated balance sheet as of December 31, 2025 has been derived from the audited consolidated financial statements at that date but does not include all information and footnotes required by GAAP for complete financial statements. These unaudited condensed consolidated financial statements should be read in conjunction with the audited financial statements included in the Annual Report. Unaudited Condensed Consolidated Financial Statements The accompanying financial information as of March 31, 2026 is unaudited. The condensed consolidated financial statements included in this report reflect all adjustments (consisting only of normal recurring adjustments) that our management considers necessary for the fair statement of the results of operations for the interim periods covered and of our financial condition at the date of the interim balance sheet. The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with GAAP for interim financial information. Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. The results for interim periods are not necessarily indicative of the results for the entire year or any other interim period. The accompanying condensed consolidated financial statements and related financial information should be read in conjunction with the audited financial statements and the related notes thereto included in our Annual Report.
Consolidation	Basis of Presentation and Consolidation The condensed 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 former wholly owned Australian subsidiary, Kezar Life Sciences Australia Pty Ltd., a proprietary company limited by shares, which was dissolved as of September 29, 2025. All intercompany balances and transactions have been eliminated upon consolidation. The condensed consolidated balance sheet as of December 31, 2025 has been derived from the audited consolidated financial statements at that date but does not include all information and footnotes required by GAAP for complete financial statements. These unaudited condensed consolidated financial statements should be read in conjunction with the audited financial statements included in the Annual Report. Unaudited Condensed Consolidated Financial Statements The accompanying financial information as of March 31, 2026 is unaudited. The condensed consolidated financial statements included in this report reflect all adjustments (consisting only of normal recurring adjustments) that our management considers necessary for the fair statement of the results of operations for the interim periods covered and of our financial condition at the date of the interim balance sheet. The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with GAAP for interim financial information. Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. The results for interim periods are not necessarily indicative of the results for the entire year or any other interim period. The accompanying condensed consolidated financial statements and related financial information should be read in conjunction with the audited financial statements and the related notes thereto included in our Annual Report.
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 revenue and expenses during the reporting period. Significant items subject to such judgments, estimates and assumptions include the valuation of marketable securities, impairment of long-lived assets, determining the fair-value of stock-based compensation, and evaluating the progress to completion of external 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 judgments, estimates and assumptions or revise the carrying value of its assets or liabilities. These estimates may change as new events occur and additional information is obtained and are recognized in the consolidated financial statements as soon as they become known. Actual results could differ from those estimates and any such differences may be material to the Company’s condensed consolidated financial statements.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements In December 2025, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update No. 2025-12 Codification Improvements (“ASU 2025-12”), which address thirty-three issues, representing amendments to Accounting Standard Codification topics that clarify, correct errors or make minor improvements. The amendments make the Codification easier to understand and apply. ASU 2025-12 is effective for the Company in its annual reporting for fiscal year 2027, and in interim periods beginning in fiscal year 2027. Early adoption and retrospective application are permitted on an issue-by-issue basis. The Company is currently evaluating the impact of the adoption of ASU 2025-12 on its financial statements. In December 2025, the FASB issued Accounting Standards Update No. 2025-11 Interim Reporting (Topic 270) – Narrow-Scope Improvements (“ASU 2025-11”), which clarifies the guidance in Topic 270 to improve the consistency of interim financial reporting. ASU 2025-11 provides a comprehensive list of required interim disclosures and introduces a disclosure principle requiring entities to disclose events since the end of the last annual reporting period that have a material impact on the entity. ASU 2025-11 is effective for the Company in its annual reporting for fiscal year 2028, and in interim periods beginning in fiscal year 2028. Early adoption and retrospective application are permitted. The Company is currently evaluating the impact of the adoption of ASU 2025-11 on its financial statements. In September 2025, the FASB issued Accounting Standards Update No. 2025-06 Intangibles – Goodwill and Other – Internal-Use Software (Subtopic 350-40) – Targeted Improvements to the Accounting for Internal-Use Software (“ASU 2025-06”) to clarify and modernize the accounting for costs related to internal-use software by removing all references to software development project stages and clarifying the threshold entities apply to begin capitalizing costs. ASU 2025-06 is effective for the Company in its annual reporting for fiscal year 2028 on a prospective basis. Early adoption and retrospective reporting are permitted. The Company is currently evaluating the impact of the adoption of ASU 2025-06 on its financial statements. In November 2024, the FASB issued Accounting Standards Update No. 2024-03 Income Statement– Reporting Comprehensive Income – Expense Disaggregation Disclosures (“ASU 2024-03”), which requires more detailed information about specified categories of expenses included in certain expense captions presented on the face of the income statement. ASU 2024-03 is effective for fiscal years beginning after December 15, 2026 and for interim periods within fiscal years beginning after December 15, 2027. Early adoption is permitted. The amendments may be applied either prospectively to financial statements issued for reporting periods after the effective date of this ASU or retrospectively to all prior periods presented in the financial statements. The Company is currently evaluating the impact of the adoption of ASU 2024-03 on its financial statements and related disclosures. There have been no other recent accounting pronouncements, changes in accounting pronouncements or recently adopted accounting guidance that are expected to have a material impact on the Company’s condensed consolidated financial statements upon adoption.
Fair Value Measurements	Financial assets and liabilities are recorded at fair value. The carrying amount of certain financial instruments, including 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 condensed 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 financial assets or liabilities measured using Level 3 inputs as of March 31, 2026 or December 31, 2025.

- Definition

Disclosure of accounting policy for the use of estimates in the preparation of financial statements in conformity with generally accepted accounting principles.

+ References

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+ Details

Restructuring and Impairment Charges

3 Months Ended

Mar. 31, 2026

Restructuring and Related Activities [Abstract]

Restructuring and Impairment Charges

In October 2025, the Company announced the initiation of a process to explore a full range of strategic alternatives focused on maximizing stockholder value. In connection with the evaluation of strategic alternatives, the Company implemented a restructuring plan including workforce reduction and other cost-containment and cash conservation measures, pursuant to which the Company initially reduced its workforce by approximately 70%.

The Company recognized restructuring charges of $6.8 million, comprised primarily of one-time employee termination benefits and long-lived assets impairment costs during the year ended December 31, 2025. The Company further recognized restructuring charges of $0.6 million, comprised primarily of one-time employee termination benefits and long-

lived assets impairment costs during the three months ended March 31, 2026. The unpaid severance and related benefit costs included in accrued liabilities in the Condensed Consolidated Balance Sheets were $0.2 million and $1.6 million as of March 31, 2026 and December 31, 2025, respectively. Restructuring and impairment charges, recorded in the Condensed Consolidated Statement of Operations are presented in the table below (in thousands):


	Three Months Ended March 31,
	2026		2025
Severance and related benefit costs	$	493	$	—
Asset impairments	119		—
Total	$	612	$	—

The following table illustrates the accrual activity and payments relating to restructuring and impairment charges (in thousands):


	Severance and related benefit costs		Asset impairments		Total
Balance as of January 1, 2025	$	—	$	—	$	—
Restructuring charges	5,741		1,096		6,837
Cash payments made	(4,185)		—		(4,185)
Non-cash charges	—		(1,096)		(1,096)
Balance as of December 31, 2025	$	1,556	$	—	$	1,556
Restructuring charges	493		119		612
Cash payments made	(1,870)		—		(1,870)
Non-cash charges	—		(119)		(119)
Balance as of March 31, 2026	$	179	$	—	$	179

Balance Sheet Components - Summary of Accrued and Other Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accrued preclinical and research costs	$ 25	$ 1,686
Accrued severance related costs	179	1,556
Accrued clinical costs	4	93
Accrued employee-related costs	0	66
Accrued professional services	850	42
Others	77	298
Total accrued liabilities	$ 1,135	$ 3,741

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Statement of Comprehensive Income [Abstract]
Net loss	$ (5,756)	$ (16,556)
Other comprehensive income (loss):
Foreign currency translation adjustments	0	5
Unrealized loss on marketable securities	0	(75)
Total other comprehensive income (loss), net of tax	0	(70)
Comprehensive loss	$ (5,756)	$ (16,626)

- Definition

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

+ References + Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

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+ Details

Fair Value Measurements (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	$ 66,229	$ 71,878
U.S. Treasury money market funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	66,229	71,878
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	66,229	71,878
Level 1 \| U.S. Treasury money market funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	66,229	71,878
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	0	0
Level 2 \| U.S. Treasury money market funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	0	0
Level 3 \| U.S. Treasury money market funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	$ 0	$ 0

Restructuring and Impairment Charges - Summary of Restructuring and Impairment Charges (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Restructuring and Related Activities [Abstract]
Severance and related benefit costs	$ 493	$ 0
Asset impairments	119	0
Total	$ 612	$ 0

Subsequent Events (Details)	Apr. 01, 2026	Apr. 13, 2026 shares $ / shares
Subsequent Event [Line Items]
Termination benefit, health insurance premium worth	12 months
Tang Capital Partners, LP \| Kezar Life Sciences Inc
Subsequent Event [Line Items]
Ownership percentage	9.00%
Subsequent Event
Subsequent Event [Line Items]
Options granted expiry period (in years)	90 days
Subsequent Event \| Kezar Life Sciences Inc \| Tang Capital Partners, LP
Subsequent Event [Line Items]
Business combination, price per share (usd per share) \| $ / shares		$ 6.955
Number of contingent value rights (in shares) \| shares		1

Income Taxes (Details) - USD ($)	3 Months Ended
Income Taxes (Details) - USD ($)	Mar. 31, 2026	Mar. 31, 2025
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 0	$ 0

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References

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+ Details

Restructuring and Impairment Charges - Additional Information (Details) - USD ($) $ in Thousands		1 Months Ended	3 Months Ended		12 Months Ended
	Nov. 06, 2025	Oct. 31, 2025	Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, number of positions eliminated, period percent	70.00%	70.00%
Restructuring and impairment charges			$ 612	$ 0
Severance and related benefit costs
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment charges			$ 200		$ 1,600

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References + Details

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Cash flows from operating activities:
Net loss	$ (5,756)	$ (16,556)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	47	251
Stock-based compensation	653	2,779
Amortization of premiums and discounts on marketable securities	0	(688)
Amortization of debt discount and issuance costs and other non-cash interest	0	159
Loss on fixed asset write-off	119	0
Gain on sale of nonfinancial asset	(1,000)	0
Gain on disposition of fixed assets	(9)	0
Changes in operating assets and liabilities
Prepaid expenses and other current assets	2,000	(714)
Other assets	0	1,741
Accounts payable, accrued and other current liabilities	(2,840)	(3,597)
Operating lease assets and liabilities	(659)	(565)
Net cash used in operating activities	(7,445)	(17,190)
Cash flows from investing activities:
Purchases of property and equipment	0	(8)
Proceeds from sale of nonfinancial asset	1,000	0
Proceeds from sale of fixed assets	529	0
Maturities of marketable securities	0	13,750
Net cash provided by investing activities	1,529	13,742
Cash flows from financing activities:
Repayment of loan principal	0	(1,304)
Proceeds from issuance of common stock under employee stock incentive plans	267	0
Net cash provided by (used in) financing activities	267	(1,304)
Effect of exchange rate changes on cash and cash equivalents	0	5
Net decrease in cash and cash equivalents	(5,649)	(4,747)
Cash and cash equivalents at the beginning of period	71,878	41,749
Cash and cash equivalents at the end of period	66,229	37,002
Supplemental disclosures
Cash paid for interest	$ 0	$ 189

Lease

3 Months Ended

Mar. 31, 2026

Leases [Abstract]

Lease

In November 2022, the Company entered into an amendment to the lease agreement for its corporate headquarters in South San Francisco, California, which expanded the leased premises in the same building as its corporate headquarters and extended 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 (“ROU”) assets.

In December 2023, the Company committed to a plan to sublease Suite 400 of its corporate headquarters in connection with a workforce reduction and evaluated the recoverability of ROU asset by comparing the carrying amount of the asset to future net undiscounted cash flows associated with the asset. The ROU asset is considered to be impaired if the carrying amount of the assets exceeds the fair value of the assets. Consequently, the Company recognized a $2.7 million impairment charge in 2023. In June 2024, the Company recognized an additional $1.5 million impairment charge in relation to Suite 400 to write off the net book value of the ROU asset as the estimated future cash flow from sublease income is zero due to then-current market conditions.

On April 1, 2026, the Company entered into a lease termination agreement with the landlord and surrendered the premises to the landlord in the condition required under the lease. The lease termination agreement provides for the early termination of the lease and the Company agreed to pay the landlord approximately $2.0 million in fulfillment of its remaining obligations under the lease, consisting of (i) approximately $1.3 million paid by the Company to lessor concurrently with the execution of the lease termination agreement and (ii) the Company’s surrender of the approximately $0.7 million held by the lessor as a security deposit.

Information related to the Company’s lease liabilities were as follows (in thousands):


	Three months ended March 31, 2026
Cash paid for operating lease liabilities	$	972
Operating lease costs	371
Variable lease costs	447


Maturities of lease liabilities as of March 31, 2026 were as follows:
Less than 12 months	$	1,388
Total undiscounted lease payments	1,388
Less: imputed interest	(34)
Total lease liabilities	$	1,354

Operating lease liabilities, current	$	1,354
Operating lease liabilities, noncurrent	—
Total operating lease liabilities	$	1,354

Stock-Based Compensation

3 Months Ended

Mar. 31, 2026

Share-Based Payment Arrangement [Abstract]

Stock-Based Compensation

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 300,000 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 receive grants under the Inducement Plan.

As of March 31, 2026, options to purchase 4,419 shares of common stock were outstanding and 295,581 shares were available for future issuance under the Inducement Plan. In connection with the Merger, the Inducement Plan will terminate as of the effective time of the Merger.

2018 Equity Incentive Plan

In June 2018, the Company’s board of directors adopted and the 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 incentive stock options (“ISOs”), NSOs, stock appreciation rights, restricted stock awards, RSUs and other stock-based awards. As of March 31, 2026, options to purchase 1,112,830 shares of common stock and no RSUs were outstanding, and 779,477 shares were available for future issuance under the 2018 Plan. In connection with the Merger, the 2018 Plan will terminate as of the effective time of the Merger.

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 400,000 shares, which is the sum of (i) 160,069 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. In December 2025, the Company’s board of directors acted such that there was no increase in the number of shares of common stock reserved for issuance under the 2018 Plan as of January 1, 2026.

The maximum number of shares that may be issued upon the exercise of ISOs under the 2018 Plan is 1,250,000 shares.

2015 Equity Incentive Plan

The 2015 Plan provided for the granting of ISOs and NSOs to employees, directors and consultants at the discretion of the Company’s 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 Company’s 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 March 31, 2026, options to purchase 116,618 shares of common stock were outstanding under the 2015 Plan. In connection with the Merger, the 2015 Plan will terminate as of the effective time of the Merger.

2018 Employee Stock Purchase Plan

In June 2018, the Company’s board of directors adopted and the 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 number of shares of common stock initially reserved for issuance under the ESPP was 20,000 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) 37,500 shares, or a lesser number of shares determined by the Company’s board of directors prior to such increase. In December 2025, the Company’s board of directors acted such that there was no increase of the number of shares of common stock reserved for issuance under the ESPP as of January 1, 2025. As of March 31, 2026, 92,996 shares of common stock had been issued under the ESPP and 40,214 shares remained available for future issuance under the ESPP.

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 subsequently authorized additional six-month offering periods, with the most recent offering period ended on November 15, 2025. In connection with the Merger, the Company will terminate the ESPP as of immediately prior to the closing date of the Merger.

Option Repricing

In July 2023, the Compensation Committee of the Company’s board of directors approved a stock option repricing (the “Option Repricing”) in which the exercise price of certain outstanding options to purchase shares of the Company’s common stock under the 2018 Plan was reduced to $22.80 per share, the closing price of the Common Stock on July 24, 2023. The incremental stock-based compensation expense resulting from the Option Repricing was $49 thousand and $0.1 million for the three months ended March 31, 2026 and 2025, respectively.

As of March 31, 2026, there was $0.1 million remaining related to the unvested option shares which will be primarily amortized over the remaining requisite service periods through the end of 2026.

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 Options Outstanding	Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value
Outstanding as of December 31, 2025	1,647,096	$	17.29	5.0	$	73
Options exercised	(42,139)	$	6.35		$	28
Options cancelled/forfeited	(371,090)	$	17.02
Outstanding as of March 31, 2026	1,233,867	$	17.74	6.1	$	390
Vested and exercisable as of March 31, 2026	949,099	$	20.55	5.4	$	154

There were no options granted during the three months ended March 31, 2026. The aggregate intrinsic value of exercised stock options during the three months ended March 31, 2026 was $28 thousand. 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.

Performance Option Grants Activities

On July 11, 2024, the Compensation Committee of the Company’s board of directors approved performance-based stock option grants to all employees, except the Chief Executive Officer, under the 2018 Plan. Performance-based stock options will vest upon the achievements of specified clinical trial milestones. The grant-date fair value of these performance-based stock options is calculated using the Black-Scholes option-pricing model. Performance-based stock options are included in the outstanding stock options table above. Stock-based compensation cost related to performance-based stock options is recognized over the period from the date the performance condition is determined to be probable of occurring through the

date the applicable condition is expected to be met. If the performance condition is not considered probable of being achieved, no stock-based compensation is recognized until such time as the performance condition is considered probable of being achieved and related compensation cost would be recognized through a cumulative catch-up adjustment in the period of change. Stock-based compensation expenses of $0 and $0.3 million related to performance-based stock options were recognized during the three months ended March 31, 2026 and 2025, respectively. As of March 31, 2026, all performance-based option grants have been fully vested.

Restricted Stock Units Activity

There were no RSUs granted during the three months ended March 31, 2026. One-third of each RSU previously granted vests annually following the vesting commencement dates, over a vesting period of three 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 expenses over the respective vesting terms.


	Number of RSUs Outstanding	Weighted Average Grant-Date Fair Price
Outstanding as of December 31, 2025	497	$	68.40
RSUs vested	(497)	$	68.40
Outstanding as of March 31, 2026	—	$	—

Stock-Based Compensation Expense

Total stock-based compensation expense recognized by function was as follows (in thousands):


	Three Months Ended March 31,
	2026		2025
Research and development	$	7	$	996
General and administrative	646		1,783
Total stock-based compensation expense	$	653	$	2,779

As of March 31, 2026, the unrecognized stock-based compensation cost related to outstanding unvested stock options that are expected to vest was $2.6 million with an estimated weighted average amortization period of 1.9 years.

The fair value of the stock options granted is calculated using the Black-Scholes option-pricing model with the following range of assumptions:


	Three Months Ended March 31,
	2026	2025
Expected term (years)	0.0	5.5 - 6.0
Expected volatility	—%	84.6 - 86.0%
Risk-free interest rate	—%	4.4 - 4.5%
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. The expected volatility is based on the daily historical volatility of the Company’s common stock covering the estimated expected term. 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 not paid, and does not anticipate paying, cash dividends on its shares of common stock; therefore, the expected dividend yield is zero.

Fair Value Measurements

3 Months Ended

Mar. 31, 2026

Fair Value Disclosures [Abstract]

Fair Value Measurements

Financial assets and liabilities are recorded at fair value. The carrying amount of certain financial instruments, including 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 condensed 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 financial assets or liabilities measured using Level 3 inputs as of March 31, 2026 or December 31, 2025.


	March 31, 2026
	Total		Level 1		Level 2		Level 3
Financial Assets:
Cash equivalents:
U.S. Treasury money market funds	$	66,229	$	66,229	$	—	$	—
Total	$	66,229	$	66,229	$	—	$	—


	December 31, 2025
	Total		Level 1		Level 2		Level 3
Financial Assets:
Cash equivalents:
U.S. Treasury money market funds	$	71,878	$	71,878	$	—	$	—
Total	$	71,878	$	71,878	$	—	$	—

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (bbb)(1)
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-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 820
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-Name Accounting Standards Codification
-Section 55
-Paragraph 107
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482078/820-10-55-107

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 820
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-Name Accounting Standards Codification
-Section 55
-Paragraph 100
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482078/820-10-55-100

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(3)
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-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
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-Name Accounting Standards Codification
-Section 50
-Paragraph 6A
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-6A

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2E
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2E

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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-Paragraph 6A
-Subparagraph (h)
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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-Paragraph 6A
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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-Subparagraph (e)
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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Reference 12: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 940
-SubTopic 820
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478119/940-820-50-1

+ Details

Everest Collaboration (Details) - Everest License Agreement - USD ($)	1 Months Ended	3 Months Ended		12 Months Ended
	Oct. 31, 2023	Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaborative agreement upfront payments collected	$ 7,000,000.0
Additional milestone payments on achievement (up to)	$ 125,500,000
Noncurrent unbilled receivable from collaboration		$ 0
Contra research and development expense		0	$ 0
Collaboration Revenue
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaboration revenue				$ 7,000,000.0
Development, Regulatory and Commercial Milestones
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaboration revenue		0
Royalty
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaboration revenue		$ 0

Net Loss Per Share

3 Months Ended

Mar. 31, 2026

Earnings Per Share [Abstract]

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):


	Three Months Ended March 31,
	2026		2025
Numerator:
Net loss	$	(5,756)	$	(16,556)
Denominator:
Weighted-average shares of common stock outstanding	7,343,909		7,305,658
Net loss per share, basic and diluted	$	(0.78)	$	(2.27)

Basic net loss per common share is calculated by dividing net loss by the weighted-average number of shares of common stock outstanding during the period, without consideration of common share equivalents. Diluted net loss per common share is computed by dividing net loss by the weighted-average number of shares of common stock and common share equivalents outstanding for the period. Common share equivalents are only included in the calculation of diluted net loss per common share when their effect is dilutive.

Potential dilutive securities, which include, vested and unvested options to purchase common stock and RSUs subject to future vesting have been excluded from the computation of diluted net loss per share as the effect is antidilutive. Therefore, the denominator used to calculate both basic and diluted net loss per common share is the same in all periods presented.


	Three Months Ended March 31,
	2026	2025
Stock options to purchase common stock	1,233,867	2,035,773
Restricted stock units subject to future vesting	—	8,451
Total	1,233,867	2,044,224

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Operating expenses:
Research and development	$ 1,545	$ 12,180
General and administrative	5,208	5,449
Restructuring and impairment charges	612	0
Total operating expenses	7,365	17,629
Loss from operations	(7,365)	(17,629)
Interest income	609	1,420
Gain on sale of nonfinancial asset	1,000	0
Interest expense	0	(347)
Net loss	$ (5,756)	$ (16,556)
Net loss per common share, basic (in dollars per share)	$ (0.78)	$ (2.27)
Net loss per common share, diluted (in dollars per share)	$ (0.78)	$ (2.27)
Weighted-average shares used to compute net loss per common share, basic (in shares)	7,343,909	7,305,658
Weighted-average shares used to compute net loss per common share, diluted (in shares)	7,343,909	7,305,658

Organization and Description of the Business	3 Months Ended
Organization and Description of the Business	Mar. 31, 2026
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of the Business	Organization and Description of the Business Description of Business Kezar Life Sciences, Inc. (the “Company,” “we,” “us,” or “our”) was incorporated in the state of Delaware in February 2015 and commenced operations in June 2015. The Company is a clinical-stage biotechnology company developing novel small molecule therapeutics to treat unmet needs in immune-mediated diseases. The Company’s principal operations are in South San Francisco, California, and it operates in one segment. The Agreement and Plan of Merger On March 30, 2026, the Company entered into an Agreement and Plan of Merger (the “Merger Agreement”) by and among the Company, Aurinia Pharma U.S., Inc., a Delaware corporation (“Parent” or “Aurinia”), Aurinia Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of Aurinia (“Merger Sub” and together with Parent, the “Buyer Entities”), and, solely for purposes of Section 10.13 of the Merger Agreement, Aurinia Pharmaceuticals Inc., a company incorporated under the laws of the Province of Alberta (“Ultimate Parent”), and the parent entity of Parent. Pursuant to the Merger Agreement, and upon the terms and subject to the conditions thereof, Parent caused Merger Sub to commence a cash tender offer (the “Offer”) on April 13, 2026. The Offer consists of an offer to purchase all of the outstanding shares of common stock of the Company, par value $0.001 per share (the “Shares”), for (i) $6.955 per Share, payable in cash, without interest (such amount, or any different amount per Share paid pursuant to the Offer, the “Cash Amount”), plus (ii) one contingent value right per Share (each, a “CVR”), which represents the right to receive certain payments in cash in accordance with the terms and subject to the conditions of a contingent value rights agreement (the “CVR Agreement”) to be entered into by and among Ultimate Parent, the Buyer Entities, a representative, agent and attorney in fact of the CVR holders and a rights agent (the Cash Amount plus one CVR, together, the “Offer Price”). Enodia Asset Purchase Agreement On March 6, 2026, the Company entered into an asset purchase agreement (the “Asset Purchase Agreement”) with Enodia Therapeutics SAS (“Enodia”), under which Enodia has acquired the Company’s assets from its Sec61-based discovery and development program. Under the terms of the Asset Purchase Agreement, the Company received initial upfront payments totaling $1.0 million, and may receive future payments from Enodia upon achievement of certain development, regulatory and commercial milestones, for a potential total of up to $127 million. In addition, Enodia will pay the Company tiered royalties on any net sales, subject to certain reductions for patent expiration, generic competition and payments for licenses to third party patents. 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 product candidates. The Company has not yet generated product sales and as a result has experienced operating losses since inception and had an accumulated deficit of $496.3 million as of March 31, 2026. Management believes that its existing cash and cash equivalents will be sufficient to fund the Company’s cash requirements for at least 12 months following the issuance of these financial statements. Restructuring In October 2025, the Company announced plans to explore a full range of strategic alternatives focused on maximizing stockholder value. If the process for evaluating strategic alternatives does not result in the Company consummating a transaction or any other strategic outcome, the Board of Directors may decide to pursue a dissolution and liquidation of the Company. On November 6, 2025, the Company reduced its workforce by approximately 70% in connection with its strategic review process. In connection with the restructuring, the Company recorded a restructuring charge of $6.8 million in the fourth quarter of 2025, consisting primarily of one-time severance and termination benefit expense for employees terminated with separation dates before December 31, 2025, and a charge related to the impairment of property and equipment. The Company further recorded a restructuring charge of $0.6 million in the first quarter of 2026. The restructuring charge in the first quarter of 2026 included one-time severance and termination benefit expense for employees terminated with separation dates before March 31, 2026, and a charge related to fixed asset write-off. Refer to Note 11 for additional information on the restructuring.

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2026	Dec. 31, 2025
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	250,000,000	250,000,000
Common stock, shares issued (in shares)	7,374,375	7,331,739
Common stock, shares outstanding (in shares)	7,374,375	7,331,739
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0

- Definition

Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
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-Name Accounting Standards Codification
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-URI https://asc.fasb.org/1943274/2147480100/505-10-S45-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Reference 8: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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Reference 10: http://www.xbrl.org/2009/role/commonPracticeRef
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-Subparagraph (SX 210.6-09(7))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479134/946-220-S99-3

+ Details

- Definition

The maximum number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) permitted to be issued by an entity's charter and bylaws.

+ References + Details

- Definition

Number of shares issued for nonredeemable preferred shares and preferred shares redeemable solely at option of issuer. Includes, but is not limited to, preferred shares issued, repurchased, and held as treasury shares. Excludes preferred shares classified as debt.

+ References + Details

- Definition

Aggregate share number for all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by stockholders. Does not include preferred shares that have been repurchased.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section S45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480100/505-10-S45-2

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477657/942-210-S45-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
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-Paragraph 1
-Publisher FASB
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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-Section S50
-Paragraph 11
-Publisher FASB
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 946
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-Name Accounting Standards Codification
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-Publisher FASB
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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Reference 11: http://www.xbrl.org/2009/role/commonPracticeRef
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+ Details

Segment Reporting - Summary of Financial Information for Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
External costs by program
Research and development	$ 1,545	$ 12,180
General and administrative	5,208	5,449
Total operating expenses	7,365	17,629
Loss from operations	(7,365)	(17,629)
Interest income	609	1,420
Net loss	(5,756)	(16,556)
Reportable Segment
Internal costs
Total salary / benefits	1,896	5,394
External costs by program
General and administrative	3,943	2,430
Other segment items	819	3,030
Total operating expenses	7,365	17,629
Loss from operations	(7,365)	(17,629)
Interest income	609	1,420
Gain on sale of nonfinancial asset	1,000	0
Interest expense	0	(347)
Net loss	(5,756)	(16,556)
Reportable Segment \| Zetomipzomib
External costs by program
Research and development	698	6,091
Reportable Segment \| KZR-261
External costs by program
Research and development	$ 9	$ 684

Balance Sheet Components - Summary of Prepaid Expenses And Other Current Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Unbilled receivable from Everest, current (Note 8)	$ 0	$ 1,741
Deposits for operating lease	674	674
Insurance	226	463
Interest receivable	206	184
Licenses, dues and subscriptions	38	72
Others	190	200
Total prepaid expenses and other current assets	$ 1,334	$ 3,334

Balance Sheet Components - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Depreciation expense	$ 47	$ 300

Lease (Tables)

3 Months Ended

Mar. 31, 2026

Leases [Abstract]

Summary of Lease Liabilities

Information related to the Company’s lease liabilities were as follows (in thousands):


	Three months ended March 31, 2026
Cash paid for operating lease liabilities	$	972
Operating lease costs	371
Variable lease costs	447

Summary of Maturities of Lease Liabilities


Maturities of lease liabilities as of March 31, 2026 were as follows:
Less than 12 months	$	1,388
Total undiscounted lease payments	1,388
Less: imputed interest	(34)
Total lease liabilities	$	1,354

Operating lease liabilities, current	$	1,354
Operating lease liabilities, noncurrent	—
Total operating lease liabilities	$	1,354

Net Loss Per Share - Summary of Anti-dilutive Outstanding Shares of Common Stock Equivalents Excluded from Computation of Diluted Net Loss per Share (Details) - shares	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net loss per share (in shares)	1,233,867	2,044,224
Stock options to purchase common stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net loss per share (in shares)	1,233,867	2,035,773
Restricted stock units subject to future vesting
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net loss per share (in shares)	0	8,451

Lease - Summary of Operating Lease Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Leases [Abstract]
Operating lease liabilities, current	$ 1,354	$ 2,326
Operating lease liabilities, noncurrent	0
Total operating lease liabilities	$ 1,354

Balance Sheet Components (Tables)

3 Months Ended

Mar. 31, 2026

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Summary of Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets consisted of the following (in thousands):


	March 31, 2026		December 31, 2025
Unbilled receivable from Everest, current (Note 8)	$	—	$	1,741
Deposits for operating lease	674		674
Insurance	226		463
Interest receivable	206		184
Licenses, dues and subscriptions	38		72
Others	190		200
Total prepaid expenses and other current assets	$	1,334	$	3,334

Summary of Property and Equipment, Net

Property and equipment, net consisted of the following (in thousands):


	March 31, 2026		December 31, 2025
Leasehold improvements	$	—	$	3,268
Computer equipment	—		184
Total property and equipment	—		3,452
Less: accumulated depreciation and amortization	—		(3,286)
Property and equipment, net	$	—	$	166

Summary of Accrued and Other Current Liabilities

Accrued liabilities consisted of the following (in thousands):


	March 31, 2026		December 31, 2025
Accrued preclinical and research costs	$	25	$	1,686
Accrued severance related costs	179		1,556
Accrued clinical costs	4		93
Accrued employee-related costs	—		66
Accrued professional services	850		42
Others	77		298
Total accrued liabilities	$	1,135	$	3,741

Subsequent Events	3 Months Ended
Subsequent Events	Mar. 31, 2026
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Executive Separation Agreements On April 1, 2026, the Company entered into Separation Agreements with each of Christopher Kirk, Ph.D., the Company's Chief Executive Officer, Marc Belsky, the Company's Chief Financial Officer, and Mark Schiller, the Company's Chief Operating Officer (collectively, the “Separation Agreements”). Pursuant to the Separation Agreements, each executive's employment will be terminated on the closing date of the Merger, or such earlier date as determined by the applicable executive and the Company's board of directors. Each Separation Agreement provides for severance benefits consistent with those resulting from a Covered Termination (as defined in each executive's respective employment agreement) within three months prior to or twelve months following the effective date of a change in control. In addition, (i) Dr. Kirk will receive his Severance Payment (as defined in his respective Separation Agreement) in a lump sum payment, less applicable payroll deductions and withholdings, and (ii) each of Mr. Belsky and Mr. Schiller will receive a one-time cash payment equal to 12 months of cost of health insurance premiums at the time of termination. The foregoing severance benefits are contingent upon a general release of claims set forth in the Separation Agreements. In connection with the Separation Agreements, the vesting and exercisability of all outstanding stock options held by each executive will be accelerated in full upon such executive's termination date, and each executive's stock options may be exercised for a period of 90 days following such termination. Tender and Support Agreement In connection with the execution of the Merger Agreement, Tang Capital Partners, LP (the “Supporting Stockholder”), solely in its capacity as a holder of Shares, entered into a Tender and Support Agreement with Parent, Merger Sub and the Company, pursuant to which the Supporting Stockholder agreed, among other things, to tender all of the Shares held by the Supporting Stockholder in the Offer, subject to certain exceptions, including the valid termination of the Merger Agreement. The Supporting Stockholder held an aggregate of approximately 9.0% of the outstanding Shares as of March 30, 2026. The Tender and Support Agreement terminates upon the earliest of (i) the termination of the Merger Agreement and (ii) the effective time of the Merger. The Merger Agreement may be terminated by either the Company or Parent if the Offer has not been consummated on or before June 28, 2026 (the “Outside Date”), subject to certain conditions set forth in the Merger Agreement. Commencement of the Offer On April 13, 2026, pursuant to the Merger Agreement, Parent caused Merger Sub to commence the Offer to purchase all of the outstanding Shares at the Offer Price, consisting of (i) $6.955 per Share in cash, without interest, plus (ii) one CVR per Share. Legal Matters In April 2026, the Company began to receive demand letters on behalf of purported stockholders challenging certain disclosures in the recommendation statement filed with the SEC on April 14, 2026 (the “Recommendation Statement”), in connection with, among other things, the Merger Agreement. As of May 11, 2026, one complaint has been filed in federal court in Illinois by a purported stockholder against the Company and certain members of its Board in connection with the Merger: Elkerson v. Kezar Life Sciences, Inc., et al., Case No. 1:26-cv-05013 (N.D. Ill. filed April 30, 2026) (the “Merger Action”). The Merger Action asserts that the Recommendation Statement omitted certain allegedly material information regarding, among other things, purported conflicts of interest, transaction fees, and TD Cowen’s financial analyses, in violation of Sections 14(e) and 14(d)(4) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and Rule 14d-9 promulgated under the Exchange Act, rendering the Recommendation Statement false and misleading. The plaintiff in the Merger Action seeks, among other things, an injunction enjoining consummation of the Merger until the Company issues additional disclosures, rescission of the Merger if consummated or rescissory damages, and costs of the action, including attorneys’ fees and expert fees and expenses.

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	COMMON STOCK	ADDITIONAL PAID-IN CAPITAL	ACCUMULATED OTHER COMPREHENSIVE LOSS	ACCUMULATED DEFICIT
Beginning balance (in shares) at Dec. 31, 2024		7,303,629
Beginning balance at Dec. 31, 2024	$ 116,916	$ 7	$ 551,570	$ (162)	$ (434,499)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee stock incentive plans (in shares)		2,171
Issuance of common stock under employee stock incentive plans	0
Stock-based compensation expense	2,779		2,779
Other comprehensive loss	(70)			(70)
Net loss	(16,556)				(16,556)
Ending balance (in shares) at Mar. 31, 2025		7,305,800
Ending balance at Mar. 31, 2025	$ 103,069	$ 7	554,349	(232)	(451,055)
Beginning balance (in shares) at Dec. 31, 2025	7,331,739	7,331,739
Beginning balance at Dec. 31, 2025	$ 70,073	$ 7	560,598	0	(490,532)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee stock incentive plans (in shares)		42,636
Issuance of common stock under employee stock incentive plans	267
Stock-based compensation expense	653		653
Other comprehensive loss	0
Net loss	$ (5,756)				(5,756)
Ending balance (in shares) at Mar. 31, 2026	7,374,375	7,374,375
Ending balance at Mar. 31, 2026	$ 65,237	$ 7	$ 561,518	$ 0	$ (496,288)

- Definition

Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

+ References

+ Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

+ Details

- Definition

Amount of equity (deficit) attributable to parent. Excludes temporary equity and equity attributable to noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
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-Name Accounting Standards Codification
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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 10: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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Reference 12: http://www.xbrl.org/2003/role/disclosureRef
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Reference 13: http://www.xbrl.org/2009/role/commonPracticeRef
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+ Details

Stock-Based Compensation - Summary of Fair Value of Employee Stock Options Granted is Calculated Using Black Scholes Option Pricing Model with Range of Assumptions (Details)	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (years)	0 years
Expected volatility	0.00%
Expected volatility, Minimum		84.60%
Expected volatility, Maximum		86.00%
Risk-free interest rate	0.00%
Risk-free interest rate, Minimum		4.40%
Risk-free interest rate, Maximum		4.50%
Expected dividend yield	0.00%	0.00%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (years)		5 years 6 months
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (years)		6 years

Stock-Based Compensation - Summary of Activity under Stock Option Plans and Related Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2026	Dec. 31, 2025
Number of Options Outstanding
Outstanding, beginning balance (in shares)	1,647,096
Option exercised (in shares)	(42,139)
Options cancelled/forfeited (in shares)	(371,090)
Outstanding, ending balance (in shares)	1,233,867	1,647,096
Weighted Average Exercise Price
Outstanding, beginning balance (in dollars per share)	$ 17.29
Option exercised (in dollars per share)	6.35
Options cancelled/forfeited (in dollars per share)	17.02
Outstanding, ending balance (in dollars per share)	$ 17.74	$ 17.29
Stock Options Additional Disclosures
Weighted average remaining contractual term, (Years) Outstanding balance	6 years 1 month 6 days	5 years
Aggregate intrinsic value, Outstanding, beginning balance	$ 73
Aggregate intrinsic value, options exercised	28
Aggregate intrinsic value, Outstanding, ending balance	$ 390	$ 73
Vested and exercisable (in shares)	949,099
Vested and exercisable (in dollars per share)	$ 20.55
Weighted average remaining contractual term, (Years) options vested and exercisable	5 years 4 months 24 days
Aggregate intrinsic value, options vested and exercisable	$ 154

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Current assets:
Cash and cash equivalents	$ 66,229	$ 71,878
Prepaid expenses and other current assets	1,334	3,334
Assets held for sale	0	520
Total current assets	67,563	75,732
Property and equipment, net	0	166
Operating lease right-of-use asset	436	749
Total assets	67,999	76,647
Current liabilities:
Accounts payable	273	507
Accrued and other current liabilities	1,135	3,741
Operating lease liabilities, current	1,354	2,326
Total current liabilities	2,762	6,574
Total liabilities	2,762	6,574
Stockholders' equity:
Common stock, $0.001 par value, 250,000,000 shares authorized as of March 31, 2026 (unaudited) and December 31, 2025; 7,374,375 and 7,331,739 shares issued and outstanding as of March 31, 2026 (unaudited) and December 31, 2025, respectively	7	7
Preferred stock, $0.001 par value, 10,000,000 shares authorized; zero shares issued and outstanding as of March 31, 2026 (unaudited) and December 31, 2025	0	0
Additional paid-in capital	561,518	560,598
Accumulated other comprehensive income (loss)	0	0
Accumulated deficit	(496,288)	(490,532)
Total stockholders' equity	65,237	70,073
Total liabilities and stockholders' equity	$ 67,999	$ 76,647

Segment Reporting (Tables)

3 Months Ended

Mar. 31, 2026

Segment Reporting [Abstract]

Summary of Financial Information for Segment

The following table represents selected financial information for our segment for the three months ended March 31, 2026 and 2025, in thousands:


	Three Months Ended March 31,
	2026		2025
Internal costs
Total salary / benefits	$	1,896	$	5,394
External costs by program
Zetomipzomib	698		6,091
KZR-261	9		684
General and administrative	3,943		2,430
Other segment items (1)	819		3,030
Total operating expenses	7,365		17,629
Loss from operations	(7,365)		(17,629)
Interest income	609		1,420
Gain on sale of nonfinancial asset	1,000		—
Interest expense	—		(347)
Consolidated segment net loss	$	(5,756)	$	(16,556)

(1) Other segment items include stock-based compensation expense, depreciation and amortization and in 2026, a loss on fixed asset write-off.

Balance Sheet Components - Summary of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Property Plant And Equipment [Line Items]
Total property and equipment	$ 0	$ 3,452
Less: accumulated depreciation and amortization	0	(3,286)
Property and equipment, net	0	166
Leasehold improvements
Property Plant And Equipment [Line Items]
Total property and equipment	0	3,268
Computer equipment
Property Plant And Equipment [Line Items]
Total property and equipment	$ 0	$ 184

- Definition

Amount of accumulated depreciation, depletion, and amortization of property, plant, and equipment. Includes, but is not limited to, land and land improvement; building; machinery and equipment; furniture and fixture; and work of art, historical treasure, or similar asset classified as collection.

+ References + Details

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition

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+ Details

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Mar. 31, 2026
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Segment Reporting

3 Months Ended

Mar. 31, 2026

Segment Reporting [Abstract]

Segment Reporting

The Company operates and manages its business as one operating segment, which primarily focuses on developing novel small molecule therapeutics to treat unmet needs in immune-mediated diseases. The Company's Chief Executive Officer serves as the Company’s Chief Operating Decision Maker, who reviews condensed consolidated financial information on a company-wide basis for purposes of allocating resources and assessing financial performance. The measure of segment assets is reported on the condensed consolidated balance sheets as total assets. The following table represents selected financial information for our segment for the three months ended March 31, 2026 and 2025, in thousands:


	Three Months Ended March 31,
	2026		2025
Internal costs
Total salary / benefits	$	1,896	$	5,394
External costs by program
Zetomipzomib	698		6,091
KZR-261	9		684
General and administrative	3,943		2,430
Other segment items (1)	819		3,030
Total operating expenses	7,365		17,629
Loss from operations	(7,365)		(17,629)
Interest income	609		1,420
Gain on sale of nonfinancial asset	1,000		—
Interest expense	—		(347)
Consolidated segment net loss	$	(5,756)	$	(16,556)

(1) Other segment items include stock-based compensation expense, depreciation and amortization and in 2026, a loss on fixed asset write-off.

- Definition

The entire disclosure for segment reporting.

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+ Details

Net Loss Per Share - Summary of Calculation of Basic and Diluted Net Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Numerator:
Net loss	$ (5,756)	$ (16,556)
Denominator:
Weighted-average shares of common stock outstanding (in shares)	7,343,909	7,305,658
Net loss per share, basic (in dollars per share)	$ (0.78)	$ (2.27)
Net loss per share, diluted (in dollars per share)	$ (0.78)	$ (2.27)

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 805
-SubTopic 60
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147476176/805-60-65-1

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 323
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (g)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478666/740-323-65-2

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483443/250-10-50-3

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482635/260-10-55-15

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (e)(4)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480175/815-40-65-1

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480175/815-40-65-1

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483443/250-10-50-11

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483443/250-10-50-11

Reference 20: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483443/250-10-50-7

Reference 21: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482689/260-10-45-2

Reference 22: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 60B
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482689/260-10-45-60B

Reference 23: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(25))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2

Reference 24: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(27))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478524/942-220-S99-1

Reference 25: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(23))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477250/944-220-S99-1

Reference 26: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482689/260-10-45-7

Reference 27: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 65
-Paragraph 4
-Subparagraph (f)(4)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481538/470-20-65-4

+ Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

+ Details

Stock-Based Compensation - Summary of Stock-Based Compensation Expense Recognized (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 653	$ 2,779
Income Statement Location: us-gaap:GeneralAndAdministrativeExpense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	646	1,783
Income Statement Location: us-gaap:ResearchAndDevelopmentExpense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 7	$ 996

Summary of Significant Accounting Policies	3 Months Ended
Summary of Significant Accounting Policies	Mar. 31, 2026
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Significant Accounting Policies The Company’s significant accounting policies are disclosed in the audited consolidated financial statements for the year ended December 31, 2025 and the notes thereto, which are included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2025, filed with the U.S. Securities and Exchange Commission (“SEC”) on March 27, 2026 (the “Annual Report”), and there have been no material changes to such policies during the three months ended March 31, 2026. Basis of Presentation and Consolidation The condensed 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 former wholly owned Australian subsidiary, Kezar Life Sciences Australia Pty Ltd., a proprietary company limited by shares, which was dissolved as of September 29, 2025. All intercompany balances and transactions have been eliminated upon consolidation. The condensed consolidated balance sheet as of December 31, 2025 has been derived from the audited consolidated financial statements at that date but does not include all information and footnotes required by GAAP for complete financial statements. These unaudited condensed consolidated financial statements should be read in conjunction with the audited financial statements included in the Annual Report. Unaudited Condensed Consolidated Financial Statements The accompanying financial information as of March 31, 2026 is unaudited. The condensed consolidated financial statements included in this report reflect all adjustments (consisting only of normal recurring adjustments) that our management considers necessary for the fair statement of the results of operations for the interim periods covered and of our financial condition at the date of the interim balance sheet. The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with GAAP for interim financial information. Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. The results for interim periods are not necessarily indicative of the results for the entire year or any other interim period. The accompanying condensed consolidated financial statements and related financial information should be read in conjunction with the audited financial statements and the related notes thereto included in our Annual Report. 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 revenue and expenses during the reporting period. Significant items subject to such judgments, estimates and assumptions include the valuation of marketable securities, impairment of long-lived assets, determining the fair-value of stock-based compensation, and evaluating the progress to completion of external 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 judgments, estimates and assumptions or revise the carrying value of its assets or liabilities. These estimates may change as new events occur and additional information is obtained and are recognized in the consolidated financial statements as soon as they become known. Actual results could differ from those estimates and any such differences may be material to the Company’s condensed consolidated financial statements. Recently Issued Accounting Pronouncements In December 2025, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update No. 2025-12 Codification Improvements (“ASU 2025-12”), which address thirty-three issues, representing amendments to Accounting Standard Codification topics that clarify, correct errors or make minor improvements. The amendments make the Codification easier to understand and apply. ASU 2025-12 is effective for the Company in its annual reporting for fiscal year 2027, and in interim periods beginning in fiscal year 2027. Early adoption and retrospective application are permitted on an issue-by-issue basis. The Company is currently evaluating the impact of the adoption of ASU 2025-12 on its financial statements. In December 2025, the FASB issued Accounting Standards Update No. 2025-11 Interim Reporting (Topic 270) – Narrow-Scope Improvements (“ASU 2025-11”), which clarifies the guidance in Topic 270 to improve the consistency of interim financial reporting. ASU 2025-11 provides a comprehensive list of required interim disclosures and introduces a disclosure principle requiring entities to disclose events since the end of the last annual reporting period that have a material impact on the entity. ASU 2025-11 is effective for the Company in its annual reporting for fiscal year 2028, and in interim periods beginning in fiscal year 2028. Early adoption and retrospective application are permitted. The Company is currently evaluating the impact of the adoption of ASU 2025-11 on its financial statements. In September 2025, the FASB issued Accounting Standards Update No. 2025-06 Intangibles – Goodwill and Other – Internal-Use Software (Subtopic 350-40) – Targeted Improvements to the Accounting for Internal-Use Software (“ASU 2025-06”) to clarify and modernize the accounting for costs related to internal-use software by removing all references to software development project stages and clarifying the threshold entities apply to begin capitalizing costs. ASU 2025-06 is effective for the Company in its annual reporting for fiscal year 2028 on a prospective basis. Early adoption and retrospective reporting are permitted. The Company is currently evaluating the impact of the adoption of ASU 2025-06 on its financial statements. In November 2024, the FASB issued Accounting Standards Update No. 2024-03 Income Statement– Reporting Comprehensive Income – Expense Disaggregation Disclosures (“ASU 2024-03”), which requires more detailed information about specified categories of expenses included in certain expense captions presented on the face of the income statement. ASU 2024-03 is effective for fiscal years beginning after December 15, 2026 and for interim periods within fiscal years beginning after December 15, 2027. Early adoption is permitted. The amendments may be applied either prospectively to financial statements issued for reporting periods after the effective date of this ASU or retrospectively to all prior periods presented in the financial statements. The Company is currently evaluating the impact of the adoption of ASU 2024-03 on its financial statements and related disclosures. There have been no other recent accounting pronouncements, changes in accounting pronouncements or recently adopted accounting guidance that are expected to have a material impact on the Company’s condensed consolidated financial statements upon adoption.

Cover - shares	3 Months Ended
Cover - shares	Mar. 31, 2026	May 07, 2026
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2026
Document Transition Report	false
Entity File Number	001-38542
Entity Registrant Name	Kezar Life Sciences, Inc.
Entity Incorporation, State or Country Code	DE
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
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		7,387,701
Entity Central Index Key	0001645666
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Document Fiscal Year Focus	2026
Document Fiscal Period Focus	Q1
Common Stock
Document Information [Line Items]
Title of 12(b) Security	Common Stock, $0.001 par value
Trading Symbol	KZR
Security Exchange Name	NASDAQ
Preferred Share Purchase Right
Document Information [Line Items]
Title of 12(b) Security	Preferred Share Purchase Rights
No Trading Symbol Flag	true
Security Exchange Name	NASDAQ

Restructuring and Impairment Charges - Summary of Accrual Activity and Payments Relating to Restructuring and Impairment Charge (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2026	Dec. 31, 2025
Restructuring Reserve [Roll Forward]
Beginning balance	$ 1,556	$ 0
Restructuring charges	612	6,837
Cash payments made	(1,870)	(4,185)
Non-cash charges	(119)	(1,096)
Ending balance	179	1,556
Severance and related benefit costs
Restructuring Reserve [Roll Forward]
Beginning balance	1,556	0
Restructuring charges	493	5,741
Cash payments made	(1,870)	(4,185)
Non-cash charges	0	0
Ending balance	179	1,556
Asset impairments
Restructuring Reserve [Roll Forward]
Beginning balance	0	0
Restructuring charges	119	1,096
Cash payments made	0	0
Non-cash charges	(119)	(1,096)
Ending balance	$ 0	$ 0

- Definition

Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

+ References + Details

Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2026

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 Options Outstanding	Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value
Outstanding as of December 31, 2025	1,647,096	$	17.29	5.0	$	73
Options exercised	(42,139)	$	6.35		$	28
Options cancelled/forfeited	(371,090)	$	17.02
Outstanding as of March 31, 2026	1,233,867	$	17.74	6.1	$	390
Vested and exercisable as of March 31, 2026	949,099	$	20.55	5.4	$	154

Summary of RSU Activity


	Number of RSUs Outstanding	Weighted Average Grant-Date Fair Price
Outstanding as of December 31, 2025	497	$	68.40
RSUs vested	(497)	$	68.40
Outstanding as of March 31, 2026	—	$	—

Summary of Stock-Based Compensation Expense Recognized

Total stock-based compensation expense recognized by function was as follows (in thousands):


	Three Months Ended March 31,
	2026		2025
Research and development	$	7	$	996
General and administrative	646		1,783
Total stock-based compensation expense	$	653	$	2,779

Summary of Fair Value of Employee Stock Options Granted is Calculated Using Black Scholes Option Pricing Model with Range of Assumptions

The fair value of the stock options granted is calculated using the Black-Scholes option-pricing model with the following range of assumptions:


	Three Months Ended March 31,
	2026	2025
Expected term (years)	0.0	5.5 - 6.0
Expected volatility	—%	84.6 - 86.0%
Risk-free interest rate	—%	4.4 - 4.5%
Expected dividend yield	—	—

Lease - Summary of Maturities of Lease Liabilities (Details) $ in Thousands	Mar. 31, 2026 USD ($)
Leases [Abstract]
Less than 12 months	$ 1,388
Total undiscounted lease payments	1,388
Less: imputed interest	(34)
Total lease liabilities	$ 1,354

Organization and Description of the Business (Details) $ / shares in Units, $ in Thousands			1 Months Ended	3 Months Ended		12 Months Ended
	Mar. 06, 2026 USD ($)	Nov. 06, 2025	Oct. 31, 2025	Mar. 31, 2026 USD ($) segment $ / shares	Mar. 31, 2025 USD ($)	Dec. 31, 2025 USD ($) $ / shares	Mar. 30, 2026 shares $ / shares
Organization And Description Of Business [Line Items]
Number of operating segments \| segment				1
Common stock, par value (in dollars per share) \| $ / shares				$ 0.001		$ 0.001
Initial upfront payments total	$ 1,000
Development and commercial milestone amount to be received	$ 127,000
Accumulated deficit				$ 496,288		$ 490,532
Restructuring and related cost, number of positions eliminated, period percent		70.00%	70.00%
Restructuring charges				612		$ 6,837
Restructuring and impairment charges				$ 612	$ 0
Minimum
Organization And Description Of Business [Line Items]
Sufficient cash and cash equivalents available period term				12 months
Aurinia Pharma U.S., Inc. \| Kezar Life Sciences Inc
Organization And Description Of Business [Line Items]
Common stock, par value (in dollars per share) \| $ / shares							$ 0.001
Business combination, price per share (usd per share) \| $ / shares							$ 6.955
Number of contingent value rights (in shares) \| shares							1

Lease - Summary of Lease Liabilities (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2026 USD ($)
Leases [Abstract]
Cash paid for operating lease liabilities	$ 972
Operating lease costs	371
Variable lease costs	$ 447