Organization and Description of the Business	9 Months Ended
Sep. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of the Business	1. Organization and Description of the Business Description of Business Kezar Life Sciences, Inc. (the “Company,” “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 discovering and developing breakthrough treatments in immune-mediated and oncologic disorders. The Company’s principal operations are in South San Francisco, California, and it operates in one segment. Liquidity Since commencing operations in mid-2015, substantially all of the Company’s efforts have been focused on research, development, and the advancement of the Company’s product candidates, zetomipzomib (KZR-616) and KZR-261. The Company’s ultimate success depends on the outcome of these ongoing research and development activities. The Company has not yet generated product sales and as a result has experienced operating losses since inception and had an accumulated deficit of $230.7 million as of September 30, 2022. The Company expects to incur additional losses in the future to conduct research and development and will need to raise additional capital to fully implement management’s business plan. The Company intends to raise such capital through the issuance of additional equity, and potentially through borrowings, strategic alliances with partner companies and other licensing transactions. However, if such financing is not available at adequate levels, the Company may need to reevaluate its operating plans. Management believes that its existing cash, cash equivalents and marketable securities will be sufficient to fund the Company’s cash requirements for at least 12 months following the issuance of these financial statements. In December 2021, the Company entered into a Sales Agreement (the “ATM Agreement”) with Cowen and Company, LLC (“Cowen”), pursuant to which the Company can offer and sell, from time to time at its sole discretion through Cowen, as its sales agent, shares of its common stock having an aggregate offering price of up to $200.0 million. Any shares of its common stock sold will be issued pursuant to the Company’s shelf registration statement on Form S-3ASR (File No. 333-261774). The Company will pay Cowen a commission equal to 3.0% of the gross sales proceeds of any shares of its common stock sold through Cowen under the ATM Agreement and also has provided Cowen with indemnification and contribution rights. No shares were sold under the ATM Agreement during the three months ended September 30, 2022. During the nine months ended September 30, 2022, the Company sold an aggregate of 11,911,699 shares of its common stock at a weighted average purchase price of $10.95 per share, pursuant to the ATM Agreement for net proceeds of approximately $126.5 million.

Organization and Description of the Business

9 Months Ended

Sep. 30, 2022

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Organization and Description of the Business

1. Organization and Description of the Business

Description of Business

Kezar Life Sciences, Inc. (the “Company,” “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 discovering and developing breakthrough treatments in immune-mediated and oncologic disorders. The Company’s principal operations are in South San Francisco, California, and it operates in one segment.

Liquidity

Since commencing operations in mid-2015, substantially all of the Company’s efforts have been focused on research, development, and the advancement of the Company’s product candidates, zetomipzomib (KZR-616) and KZR-261. The Company’s ultimate success depends on the outcome of these ongoing research and development activities. The Company has not yet generated product sales and as a result has experienced operating losses since inception and had an accumulated deficit of $230.7 million as of September 30, 2022. The Company expects to incur additional losses in the future to conduct research and development and will need to raise additional capital to fully implement management’s business plan. The Company intends to raise such capital through the issuance of additional equity, and potentially through borrowings, strategic alliances with partner companies and other licensing transactions. However, if such financing is not available at adequate levels, the Company may need to reevaluate its operating plans. Management believes that its existing cash, cash equivalents and marketable securities will be sufficient to fund the Company’s cash requirements for at least 12 months following the issuance of these financial statements.

In December 2021, the Company entered into a Sales Agreement (the “ATM Agreement”) with Cowen and Company, LLC (“Cowen”), pursuant to which the Company can offer and sell, from time to time at its sole discretion through Cowen, as its sales agent, shares of its common stock having an aggregate offering price of up to $200.0 million. Any shares of its common stock sold will be issued pursuant to the Company’s shelf registration statement on Form S-3ASR (File No. 333-261774). The Company will pay Cowen a commission equal to 3.0% of the gross sales proceeds of any shares of its common stock sold through Cowen under the ATM Agreement and also has provided Cowen with indemnification and contribution rights. No shares were sold under the ATM Agreement during the three months ended September 30, 2022. During the nine months ended September 30, 2022, the Company sold an aggregate of 11,911,699 shares of its common stock at a weighted average purchase price of $10.95 per share, pursuant to the ATM Agreement for net proceeds of approximately $126.5 million.