Organization	12 Months Ended
Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization	Note 1. Organization Description of Business Arcus Biosciences, Inc. (the Company) is a clinical-stage biopharmaceutical company focused on creating best-in-class cancer therapies. The Company’s initial focus has been on well-characterized biological pathways with significant scientific data supporting their importance. Since its inception in 2015, the Company has built a robust and highly efficient discovery capability to create highly differentiated small molecules, which the Company is developing in combination with its in-licensed monoclonal antibodies through rationally designed, indication-specific, adaptive clinical trial designs. Initial Public Offering On March 21, 2018, the Company completed its initial public offering (IPO) pursuant to which the Company issued 9,200,000 shares of common stock, including the exercise of the underwriters’ overallotment option to purchase 1,200,000 shares of common stock, at an offering price at $15.00 per share. The Company received aggregate net proceeds of approximately $124.7 million after deducting underwriting discounts and other offering related costs. In addition, in connection with the completion of the Company’s IPO, all outstanding shares of convertible preferred stock were converted into 30,459,574 shares of common stock, and the Company amended and restated its certificate of incorporation and bylaws, which, among other things, changed the authorized capital stock to 400,000,000 shares of common stock and 10,000,000 shares of preferred stock, each with a par value of $0.0001 per share.

Organization

12 Months Ended

Dec. 31, 2019

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Note 1. Organization

Description of Business

Arcus Biosciences, Inc. (the Company) is a clinical-stage biopharmaceutical company focused on creating best-in-class cancer therapies. The Company’s initial focus has been on well-characterized biological pathways with significant scientific data supporting their importance. Since its inception in 2015, the Company has built a robust and highly efficient discovery capability to create highly differentiated small molecules, which the Company is developing in combination with its in-licensed monoclonal antibodies through rationally designed, indication-specific, adaptive clinical trial designs.

Initial Public Offering

On March 21, 2018, the Company completed its initial public offering (IPO) pursuant to which the Company issued 9,200,000 shares of common stock, including the exercise of the underwriters’ overallotment option to purchase 1,200,000 shares of common stock, at an offering price at $15.00 per share. The Company received aggregate net proceeds of approximately $124.7 million after deducting underwriting discounts and other offering related costs. In addition, in connection with the completion of the Company’s IPO, all outstanding shares of convertible preferred stock were converted into 30,459,574 shares of common stock, and the Company amended and restated its certificate of incorporation and bylaws, which, among other things, changed the authorized capital stock to 400,000,000 shares of common stock and 10,000,000 shares of preferred stock, each with a par value of $0.0001 per share.