Organization	12 Months Ended
Dec. 31, 2022
Accounting Policies [Abstract]
Organization	1. Organization Prometheus Biosciences, Inc. (the Company) was incorporated in the state of Delaware on October 26, 2016 under the name Precision IBD, Inc. and is headquartered in San Diego, California. The Company changed its name to Prometheus Biosciences, Inc. on October 1, 2019. The Company’s business is focused on the discovery, development and commercialization of novel therapeutic and diagnostic products for the treatment of immune-mediated diseases, starting first with inflammatory bowel disease (IBD). In June 2019, the Company acquired Prometheus Laboratories, Inc. (PLI) and the related intangible assets used by PLI. PLI was wholly owned by Nestlé Health Science US Holdings, Inc. and the related intangible assets were owned by Societé Des Produits Nestlé S.A (together, Nestlé) (see Note 7). PLI markets and conducts several laboratory developed tests useful to gastroenterologists in monitoring their IBD patients’ disease state and informing their therapeutic decisions. On December 31, 2020, the Company completed the spinoff of PLI by making an in-kind distribution of 100% of its interest in PLI to the Company’s stockholders of record on December 30, 2020 (see Note 7). Reverse Stock Split On March 5, 2021, the Company effected a one-for-ten reverse stock split of the Company’s common stock (the Reverse Stock Split). The par value and the authorized shares of the common stock were not adjusted as a result of the Reverse Stock Split. All issued and outstanding common stock and the conversion prices and ratio of the convertible preferred stock have been retroactively adjusted to reflect this Reverse Stock Split for all periods presented. Initial Public Offering On March 16, 2021, the Company completed its initial public offering (IPO) with the sale of 11,500,000 shares of common stock, which included the exercise in full by the underwriters of their option to purchase 1,500,000 additional shares, at an initial public offering price of $19.00 per share and received gross proceeds of $218.5 million, which resulted in net proceeds to the Company of approximately $199.8 million, after deducting underwriting discounts and commissions of approximately $15.3 million and offering-related transaction costs of approximately $3.4 million. In addition, in connection with the completion of the IPO, all outstanding shares of convertible preferred stock were converted into 25,485,955 shares of the Company’s common stock; outstanding warrants to purchase 148,848 shares of convertible preferred stock were converted into warrants to purchase 14,884 shares of the Company’s common stock; and the Company’s certificate of incorporation was amended and restated to authorize 400,000,000 shares of common stock and 40,000,000 shares of undesignated preferred stock. Liquidity The Company has incurred net losses since inception, experienced negative cash flows from operations, and as of December 31, 2022, has an accumulated deficit of $331.1 million. The Company has historically financed its operations primarily through private placements of convertible preferred stock, proceeds from the Company's IPO in March 2021 and proceeds from the sale of its common stock through a public offering and an "at the market" offering. The Company expects operating losses and negative cash flows from operations to continue for the foreseeable future. The Company believes its current capital resources will be sufficient for the Company to continue as a going concern for at least one year from the issuance date of these consolidated financial statements. The Company will be required to raise additional capital, however, there can be no assurance as to whether additional financing will be available on terms acceptable to the Company, if at all. If sufficient funds on acceptable terms are not available when needed, it would have a negative impact on the Company’s financial condition and could force the Company to delay, limit, reduce, or terminate product development or future commercialization efforts or grant rights to develop and market product candidates or testing products that the Company would otherwise plan to develop.

Organization

12 Months Ended

Dec. 31, 2022

Prometheus Biosciences, Inc. (the Company) was incorporated in the state of Delaware on October 26, 2016 under the name Precision IBD, Inc. and is headquartered in San Diego, California. The Company changed its name to Prometheus Biosciences, Inc. on October 1, 2019. The Company’s business is focused on the discovery, development and commercialization of novel therapeutic and diagnostic products for the treatment of immune-mediated diseases, starting first with inflammatory bowel disease (IBD).

In June 2019, the Company acquired Prometheus Laboratories, Inc. (PLI) and the related intangible assets used by PLI. PLI was wholly owned by Nestlé Health Science US Holdings, Inc. and the related intangible assets were owned by Societé Des Produits Nestlé S.A (together, Nestlé) (see Note 7). PLI markets and conducts several laboratory developed tests useful to gastroenterologists in monitoring their IBD patients’ disease state and informing their therapeutic decisions.

On December 31, 2020, the Company completed the spinoff of PLI by making an in-kind distribution of 100% of its interest in PLI to the Company’s stockholders of record on December 30, 2020 (see Note 7).

Reverse Stock Split

On March 5, 2021, the Company effected a one-for-ten reverse stock split of the Company’s common stock (the Reverse Stock Split). The par value and the authorized shares of the common stock were not adjusted as a result of the Reverse Stock Split. All issued and outstanding common stock and the conversion prices and ratio of the convertible preferred stock have been retroactively adjusted to reflect this Reverse Stock Split for all periods presented.

Initial Public Offering

On March 16, 2021, the Company completed its initial public offering (IPO) with the sale of 11,500,000 shares of common stock, which included the exercise in full by the underwriters of their option to purchase 1,500,000 additional shares, at an initial public offering price of $19.00 per share and received gross proceeds of $218.5 million, which resulted in net proceeds to the Company of approximately $199.8 million, after deducting underwriting discounts and commissions of approximately $15.3 million and offering-related transaction costs of approximately $3.4 million.

In addition, in connection with the completion of the IPO, all outstanding shares of convertible preferred stock were converted into 25,485,955 shares of the Company’s common stock; outstanding warrants to purchase 148,848 shares of convertible preferred stock were converted into warrants to purchase 14,884 shares of the Company’s common stock; and the Company’s certificate of incorporation was amended and restated to authorize 400,000,000 shares of common stock and 40,000,000 shares of undesignated preferred stock.

Liquidity

The Company has incurred net losses since inception, experienced negative cash flows from operations, and as of December 31, 2022, has an accumulated deficit of $331.1 million. The Company has historically financed its operations primarily through private placements of convertible preferred stock, proceeds from the Company's IPO in March 2021 and proceeds from the sale of its common stock through a public offering and an "at the market" offering. The Company expects operating losses and negative cash flows from operations to continue for the foreseeable future. The Company believes its current capital resources will be sufficient for the Company to continue as a going concern for at least one year from the issuance date of these consolidated financial statements.

The Company will be required to raise additional capital, however, there can be no assurance as to whether additional financing will be available on terms acceptable to the Company, if at all. If sufficient funds on acceptable terms are not available when needed, it would have a negative impact on the Company’s financial condition and could force the Company to delay, limit, reduce, or terminate product development or future commercialization efforts or grant rights to develop and market product candidates or testing products that the Company would otherwise plan to develop.

Prometheus Biosciences, Inc. 10-K