Description of Business and Basis of Presentation	6 Months Ended
Jun. 30, 2026
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business and Basis of Presentation	1. Description of Business and Basis of Presentation Description of Business CG Oncology, Inc. (the Company) is a late-stage clinical biopharmaceutical company focused on developing and commercializing its product candidate, cretostimogene grenadenorepvec, for patients with bladder cancer. The Company is at a clinical stage and does not project to generate significant revenues if and until the U.S. Food and Drug Administration (FDA) approves its product candidate, cretostimogene, and the Company is able to commercialize this product candidate. In February 2025, SafeGuard Healthcare, LLC (SafeGuard), a wholly owned subsidiary of the Company, purchased a $26.8 million convertible note, including accrued interest, from SP Healthcare SPV I, LLC (the SPV). The SPV used the proceeds from the Note to invest and acquire substantially all of the assets of Biovire, Inc. (Biovire), a contract manufacturing organization that produces cretostimogene for the Company. In July 2025, SafeGuard converted the Note (the Conversion Event) and obtained control of both the SPV and Biovire. Refer to Note 15 for additional details on the Conversion Event. Basis of Presentation The accompanying unaudited condensed consolidated financial statements as of June 30, 2026 and for the three and six months ended June 30, 2026 and 2025 have been prepared in accordance with U.S. generally accepted accounting principles (U.S. GAAP) for interim financial information and pursuant to the rules and regulations of the U.S. Securities and Exchange Commission (SEC). Accordingly, they do not include all of the information and notes required by U.S. GAAP for complete financial statements. Because all of the disclosures required by U.S. GAAP for complete financial statements are not included herein, these unaudited condensed consolidated financial statements and the notes accompanying them should be read in conjunction with the Company’s audited financial statements for the year ended December 31, 2025 included in the Company's Annual Report on Form 10-K for the year ended December 31, 2025 (2025 Annual Report), filed with the SEC on February 27, 2026. In the opinion of management, the unaudited condensed consolidated financial statements reflect all adjustments, which include only normal and recurring adjustments, considered necessary for a fair statement of the interim periods. The preparation of financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements, as well as the reported amounts of revenue and expenses during the reporting period. Liquidity and Management’s Plans As of June 30, 2026, the Company had approximately $1,028.3 million of cash, cash equivalents and marketable securities and working capital of approximately $1,002.4 million. The Company has a relatively limited operating history, and the revenue and income potential of the Company’s business and market are unproven. The Company has experienced net losses and negative cash flows from operations since its inception and, as of June 30, 2026, the Company had an accumulated deficit of $518.2 million. During the three and six months ended June 30, 2026, the Company incurred a net loss of $79.1 million and $139.3 million, respectively, and had negative cash flows from operations of $103.4 million during the six months ended June 30, 2026. The Company will continue to incur significant costs and expenses related to its ongoing operations until it successfully develops, obtains regulatory approval, and gains market acceptance of a product candidate and achieves a level of revenues adequate to support the Company’s operations.

Description of Business and Basis of Presentation

6 Months Ended

Jun. 30, 2026

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Description of Business and Basis of Presentation

1. Description of Business and Basis of Presentation

Description of Business

CG Oncology, Inc. (the Company) is a late-stage clinical biopharmaceutical company focused on developing and commercializing its product candidate, cretostimogene grenadenorepvec, for patients with bladder cancer. The Company is at a clinical stage and does not project to generate significant revenues if and until the U.S. Food and Drug Administration (FDA) approves its product candidate, cretostimogene, and the Company is able to commercialize this product candidate.

In February 2025, SafeGuard Healthcare, LLC (SafeGuard), a wholly owned subsidiary of the Company, purchased a $26.8 million convertible note, including accrued interest, from SP Healthcare SPV I, LLC (the SPV). The SPV used the proceeds from the Note to invest and acquire substantially all of the assets of Biovire, Inc. (Biovire), a contract manufacturing organization that produces cretostimogene for the Company. In July 2025, SafeGuard converted the Note (the Conversion Event) and obtained control of both the SPV and Biovire. Refer to Note 15 for additional details on the Conversion Event.

Basis of Presentation

The accompanying unaudited condensed consolidated financial statements as of June 30, 2026 and for the three and six months ended June 30, 2026 and 2025 have been prepared in accordance with U.S. generally accepted accounting principles (U.S. GAAP) for interim financial information and pursuant to the rules and regulations of the U.S. Securities and Exchange Commission (SEC). Accordingly, they do not include all of the information and notes required by U.S. GAAP for complete financial statements. Because all of the disclosures required by U.S. GAAP for complete financial statements are not included herein, these unaudited condensed consolidated financial statements and the notes accompanying them should be read in conjunction with the Company’s audited financial statements for the year ended December 31, 2025 included in the Company's Annual Report on Form 10-K for the year ended December 31, 2025 (2025 Annual Report), filed with the SEC on February 27, 2026. In the opinion of management, the unaudited condensed consolidated financial statements reflect all adjustments, which include only normal and recurring adjustments, considered necessary for a fair statement of the interim periods.

The preparation of financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements, as well as the reported amounts of revenue and expenses during the reporting period.

Liquidity and Management’s Plans

As of June 30, 2026, the Company had approximately $1,028.3 million of cash, cash equivalents and marketable securities and working capital of approximately $1,002.4 million. The Company has a relatively limited operating history, and the revenue and income potential of the Company’s business and market are unproven. The Company has experienced net losses and negative cash flows from operations since its inception and, as of June 30, 2026, the Company had an accumulated deficit of $518.2 million. During the three and six months ended June 30, 2026, the Company incurred a net loss of $79.1 million and $139.3 million, respectively, and had negative cash flows from operations of $103.4 million during the six months ended June 30, 2026. The Company will continue to incur significant costs and expenses related to its ongoing operations until it successfully develops, obtains regulatory approval, and gains market acceptance of a product candidate and achieves a level of revenues adequate to support the Company’s operations.