Organization and Description of Business	12 Months Ended
Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	1. ORGANIZATION AND DESCRIPTION OF BUSINESS Description of Business Tempest Therapeutics, Inc. (“Tempest,” or the “Company”) is a clinical-stage oncology company advancing small molecules that combine both tumor-targeted and immune-mediated mechanisms with the potential to treat a wide range of tumors. The Company’s two novel clinical programs are TPST-1120 and TPST-1495, antagonists of PPARα and EP2/EP4, respectively. Both programs are advancing through clinical trials designed to study the agents as monotherapies and in combination with other approved agents. Tempest is also developing an orally available inhibitor of TREX-1, a target that controls activation of the cGAS/STING pathway. Tempest is headquartered in Brisbane, California. Merger with Millendo—On March 29, 2021, TempestTx, Inc. (“Private Tempest”) entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Millendo Therapeutics, Inc. (“Millendo”). Concurrent with the execution and delivery of the Merger Agreement, Private Tempest entered into funding agreements with certain investors named therein, pursuant to which the investors agreed to purchase, in the aggregate, $30.0 million of common stock of Private Tempest, convertible into securities of Millendo. On June 25, 2021, Private Tempest completed the merger with Millendo in accordance with the Merger Agreement. Prior to the effective time of the merger, Millendo effected a 1-for-15 reverse stock split, and right after the merger, Millendo changed its name to Tempest Therapeutics, Inc. Under the terms of the Merger Agreement, immediately prior to the effective time of the merger, each share of Private Tempest’s preferred stock was converted into a share of Private Tempest’s common stock. At closing of the merger, the Company issued an aggregate of approximately 5,365,899 shares of its common stock to Private Tempest stockholders, based on an exchange ratio of 0.0322 shares of the Company’s common stock for each share of Private Tempest common stock outstanding immediately prior to the merger, including those shares of common stock issued upon conversion of the Private Tempest preferred stock, resulting in approximately 6,635,345 shares of the Company’s common stock being issued and outstanding immediately following the effective time of the merger. The Company also assumed all of the outstanding and unexercised stock options and warrants to purchase shares of Private Tempest capital stock. The assumed options continue to be governed by the terms of the 2011 and 2017 Equity Incentive Plans (as discussed more in Note 9) under which the options were originally granted, with such options hence forth representing the right to purchase a number of shares of the Company’s common stock equal to 0.0322 multiplied by the number of shares of Private Tempest common stock previously represented by such options. The merger was accounted for as a reverse recapitalization in accordance with U.S. generally accepted accounting principles (“GAAP”). Under this method of accounting, Private Tempest was be deemed to be the accounting acquirer for financial reporting purposes. This determination was primarily based on the expectation that, immediately following the merger: (i) Private Tempest stockholders would own a substantial majority of the voting rights; (ii) Private Tempest would designate a substantial majority of the initial members of the board of directors of the combined company; (iii) Private Tempest’s executive management team would become the management of the combined company; and (iv) the combined company would be named Tempest Therapeutics, Inc. Accordingly, for accounting purposes, the merger was treated as the equivalent of Tempest issuing stock to acquire the net assets of Millendo. As a result of the merger, the net assets of Millendo were recorded at their acquisition-date fair value in the financial statements of Private Tempest and the reported operating results prior to the merger will be those of Private Tempest. Historical per share figures of Private Tempest have been retroactively restated based on the exchange ratio of 0.0322. Liquidity and Management Plans The accompanying financial statements have been prepared assuming the Company will continue as a going concern. The Company has incurred operating losses since inception. As of December 31, 2022, we had cash and cash equivalents of $31.2 million. Our ability to fund continued development will require additional capital, and we intend to raise such capital through the issuance of additional debt or equity including in connection with potential merger opportunities, or through business development activities. Our ability to continue as a going concern is dependent upon our ability to successfully accomplish these plans and secure sources of financing and ultimately attain profitable operations. If we are unable to obtain adequate capital, we could be forced to cease operations. On April 29, 2022, the Company completed a private investment in public equity (“PIPE”) financing from the sale of 3,149,912 shares of its common stock at a price per share of $2.36 and, and in lieu of shares of common stock, pre-funded warrants to purchase up to 3,206,020 shares of its common stock at a price per pre-funded warrant of $2.359 to EcoR1 Capital, LLC and Versant Venture Capital (the “PIPE Investors”). Net proceeds from the PIPE financings totaled approximately $14.5 million, after deducting offering expenses. The Company entered into a registration rights agreement (the “Registration Rights Agreement”) with the PIPE Investors pursuant to which the Company filed a registration statement with the SEC registering the resale of the 3,149,912 shares common stock and the 3,206,020 shares of common stock underlying the pre-funded warrants issued in the PIPE financing.

Organization and Description of Business

12 Months Ended

Dec. 31, 2022

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Organization and Description of Business

1. ORGANIZATION AND DESCRIPTION OF BUSINESS

Description of Business

Tempest Therapeutics, Inc. (“Tempest,” or the “Company”) is a clinical-stage oncology company advancing small molecules that combine both tumor-targeted and immune-mediated mechanisms with the potential to treat a wide range of tumors. The Company’s two novel clinical programs are TPST-1120 and TPST-1495, antagonists of PPARα and EP2/EP4, respectively. Both programs are advancing through clinical trials designed to study the agents as monotherapies and in combination with other approved agents. Tempest is also developing an orally available inhibitor of TREX-1, a target that controls activation of the cGAS/STING pathway. Tempest is headquartered in Brisbane, California.

Merger with Millendo—On March 29, 2021, TempestTx, Inc. (“Private Tempest”) entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Millendo Therapeutics, Inc. (“Millendo”).

Concurrent with the execution and delivery of the Merger Agreement, Private Tempest entered into funding agreements with certain investors named therein, pursuant to which the investors agreed to purchase, in the aggregate, $30.0 million of common stock of Private Tempest, convertible into securities of Millendo.

On June 25, 2021, Private Tempest completed the merger with Millendo in accordance with the Merger Agreement. Prior to the effective time of the merger, Millendo effected a 1-for-15 reverse stock split, and right after the merger, Millendo changed its name to Tempest Therapeutics, Inc. Under the terms of the Merger Agreement, immediately prior to the effective time of the merger, each share of Private Tempest’s preferred stock was converted into a share of Private Tempest’s common stock. At closing of the merger, the Company issued an aggregate of approximately 5,365,899 shares of its common stock to Private Tempest stockholders, based on an exchange ratio of 0.0322 shares of the Company’s common stock for each share of Private Tempest common stock outstanding immediately prior to the merger, including those shares of common stock issued upon conversion of the Private Tempest preferred stock, resulting in approximately 6,635,345 shares of the Company’s common stock being issued and outstanding immediately following the effective time of the merger. The Company also assumed all of the outstanding and unexercised stock options and warrants to purchase shares of Private Tempest capital stock. The assumed options continue to be governed by the terms of the 2011 and 2017 Equity Incentive Plans (as discussed more in Note
9) under which the options were originally granted, with such options hence forth representing the right to purchase a number of shares of the Company’s common stock equal to 0.0322 multiplied by the number of shares of Private Tempest common stock previously represented by such options.

The merger was accounted for as a reverse recapitalization in accordance with U.S. generally accepted accounting principles (“GAAP”). Under this method of accounting, Private Tempest was be deemed to be the accounting acquirer for financial reporting purposes. This determination was primarily based on the expectation that, immediately following the merger: (i) Private Tempest stockholders would own a substantial majority of the voting rights; (ii) Private Tempest would designate a substantial majority of the initial members of the board of directors of the combined company; (iii) Private Tempest’s executive management team would become the management of the combined company; and (iv) the combined company would be named Tempest Therapeutics, Inc. Accordingly, for accounting purposes, the merger was treated as the equivalent of Tempest issuing stock to acquire the net assets of Millendo. As a result of the merger, the net assets of Millendo were recorded at their acquisition-date fair value in the financial statements of Private Tempest and the reported operating results prior to the merger will be those of

Private Tempest. Historical per share figures of Private Tempest have been retroactively restated based on the exchange ratio of 0.0322.

Liquidity and Management Plans

The accompanying financial statements have been prepared assuming the Company will continue as a going concern. The Company has incurred operating losses since inception. As of December 31, 2022, we had cash and cash equivalents of $31.2 million. Our ability to fund continued development will require additional capital, and we intend to raise such capital through the issuance of additional debt or equity including in connection with potential merger opportunities, or through business development activities. Our ability to continue as a going concern is dependent upon our ability to successfully accomplish these plans and secure sources of financing and ultimately attain profitable operations. If we are unable to obtain adequate capital, we could be forced to cease operations.

On April 29, 2022, the Company completed a private investment in public equity (“PIPE”) financing from the sale of 3,149,912 shares of its common stock at a price per share of $2.36 and, and in lieu of shares of common stock, pre-funded warrants to purchase up to 3,206,020 shares of its common stock at a price per pre-funded warrant of $2.359 to EcoR1 Capital, LLC and Versant Venture Capital (the “PIPE Investors”). Net proceeds from the PIPE financings totaled approximately $14.5 million, after deducting offering expenses. The Company entered into a registration rights agreement (the “Registration Rights Agreement”) with the PIPE Investors pursuant to which the Company filed a registration statement with the SEC registering the resale of the 3,149,912 shares common stock and the 3,206,020 shares of common stock underlying the pre-funded warrants issued in the PIPE financing.