Organization and Description of Business	9 Months Ended
Sep. 30, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization and Description of Business	1. Organization and Description of Business Forte Biosciences, Inc. (www.fortebiorx.com), together with its subsidiaries, referred to herein as the “Company”, is a biopharmaceutical company that had been focused on developing a topical live biotherapeutic for the treatment of inflammatory skin diseases with an initial focus on atopic dermatitis (“AD”). On September 2, 2021, the Company announced that the clinical trial of FB-401 for the treatment of AD failed to achieve statistical significance for its primary endpoint. Following the announcement of the FB-401 trial results, our board of directors continues to evaluate plans for FB-401 and also commenced a process of evaluating strategic alternatives to maximize stockholder value. We have engaged a financial advisory firm to help explore our available strategic alternatives, including a possible merger, business combination, asset acquisitions or sales, collaboration or licensing arrangements. The Company entered into a business combination (“Merger”) between Forte Subsidiary, Inc. (“Forte Subsidiary”) a private entity, and Tocagen, Inc. (“Tocagen”), a publicly traded biotechnology company. The Merger closed on June 15, 2020, in which Telluride Merger Sub, Inc., a wholly-owned subsidiary of Tocagen, merged with and into Forte Subsidiary, with Forte Subsidiary surviving the Merger as a wholly-owned subsidiary of Tocagen. Immediately prior to the closing of the Merger, the shares of Tocagen common stock were adjusted with a reverse split ratio of 1‑for‑15. At the closing of the Merger, each share of Forte Subsidiary common stock outstanding immediately prior to the Merger was converted into the right to receive approximately 3.1624 shares of Tocagen common stock (before giving effect to the reverse split). All share and per share amounts have been retrospectively adjusted to give effect to the exchange of Forte Subsidiary common stock and the reverse split of Tocagen common stock. The par value per share of our capital stock was not adjusted as a result of the stock split. Immediately prior to the closing of the Merger, Tocagen changed its name to Forte Biosciences, Inc. The Company’s common stock is traded on the Nasdaq stock exchange under the ticker symbol “FBRX.” Immediately following the Merger, the former Forte Subsidiary and Tocagen security holders owned approximately 84.7% and 15.3% of the number of shares of the Company’s common stock, respectively. Prior to the Merger, Forte Subsidiary was incorporated as Forte Biosciences, Inc. under the laws of the State of Delaware on May 3, 2017 as a privately-held company. Forte Biosciences, Inc. was renamed Forte Subsidiary, Inc. in connection with the Merger. The Merger was accounted for as a reverse asset acquisition. Forte Subsidiary is deemed to be the accounting acquirer for accounting purposes and Tocagen the accounting acquiree (Note 4). Accordingly, for accounting purposes: (i) the Merger was treated as the equivalent of Forte Subsidiary issuing stock to acquire the net assets of Tocagen, (ii) the transaction price was allocated over the acquired Tocagen net assets based upon their relative fair value at the time of closing, (iii) the reported historical operating results of the combined company prior to the Merger are those of Forte Subsidiary and not of Tocagen, and (iv) for periods prior to the transaction, shareholders’ authorized capital of the combined company is presented using the historical authorized capital of Tocagen. On February 12, 2021, the Company incorporated Forte Biosciences Emerald Limited in Dublin, Ireland, for the purpose of potentially undertaking clinical trials in the European Union. Liquidity and Risks The accompanying condensed consolidated financial statements have been prepared assuming that the Company will continue as a going concern, which contemplates the realization of assets and the settlement of liabilities and commitments in the normal course of business. The condensed consolidated financial statements do not reflect any adjustments relating to the recoverability and reclassification of assets and liabilities that might be necessary if the Company is unable to continue as a going concern. Since inception, the Company has incurred losses and negative cash flows from operations. As of September 30, 2021, the Company had an accumulated deficit of $69.8 million. The Company used $13.1 million of cash in operating activities during the nine months ended September 30, 2021. Management expects to continue to incur additional losses in the foreseeable future as the Company explores its available strategic alternatives to maximize shareholder value following the announcement on September 2, 2021 of the unfavorable clinical trial results of FB-401. The Company had cash and cash equivalents of approximately $45.7 million as of September 30, 2021. The Company’s cash and cash equivalents are held at financial institutions and exceed federally insured limits. The Company believes that its existing cash and cash equivalents will be sufficient to allow the Company to fund its operations for at least 12 months from the filing date of this Form 10-Q. The Company will continue to need to raise additional capital or obtain financing from other sources. Management may fund future operations through the sale of equity and debt financings and may also seek additional capital through arrangements with strategic partners or other sources. There can be no assurance that additional funding will be available on terms acceptable to the Company, if at all. If the Company is unable to raise additional funding to meet its working capital needs in the future, it may be forced to delay or reduce the scope of its research and development programs and/or limit or cease its operations. There are numerous risks and uncertainties associated with pharmaceutical development and the Company is unable to predict the timing or amount of increased expenses on the development of future product candidates or when or if it will start to generate revenues. Even if the Company does generate revenues, it may not be able to achieve or maintain profitability. If the Company fails to become profitable or is unable to sustain profitability on a continuing basis, then it may be unable to continue its operations at planned levels and may be forced to reduce its operations. The pandemic caused by outbreaks of new strains of coronaviruses, or COVID-19 and its variants, has resulted, and may to continue to result, in significant national and global economic disruption and may adversely affect the Company’s operations. The Company is actively monitoring the impact of COVID-19 and the possible effects on its financial condition, liquidity, operations, suppliers, industry, and workforce. However, the full extent, consequences, and duration of the COVID-19 pandemic and the resulting impact on the Company cannot currently be predicted. The Company will continue to evaluate the impact that these events could have on its operations, financial position, results of operations and cash flows during the remainder of 2021.

Organization and Description of Business

9 Months Ended

Sep. 30, 2021

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Organization and Description of Business

1. Organization and Description of Business

Forte Biosciences, Inc. (www.fortebiorx.com), together with its subsidiaries, referred to herein as the “Company”, is a biopharmaceutical company that had been focused on developing a topical live biotherapeutic for the treatment of inflammatory skin diseases with an initial focus on atopic dermatitis (“AD”). On September 2, 2021, the Company announced that the clinical trial of FB-401 for the treatment of AD failed to achieve statistical significance for its primary endpoint. Following the announcement of the FB-401 trial results, our board of directors continues to evaluate plans for FB-401 and also commenced a process of evaluating strategic alternatives to maximize stockholder value. We have engaged a financial advisory firm to help explore our available strategic alternatives, including a possible merger, business combination, asset acquisitions or sales, collaboration or licensing arrangements.

The Company entered into a business combination (“Merger”) between Forte Subsidiary, Inc. (“Forte Subsidiary”) a private entity, and Tocagen, Inc. (“Tocagen”), a publicly traded biotechnology company. The Merger closed on June 15, 2020, in which Telluride Merger Sub, Inc., a wholly-owned subsidiary of Tocagen, merged with and into Forte Subsidiary, with Forte Subsidiary surviving the Merger as a wholly-owned subsidiary of Tocagen. Immediately prior to the closing of the Merger, the shares of Tocagen common stock were adjusted with a reverse split ratio of 1‑for‑15. At the closing of the Merger, each share of Forte Subsidiary common stock outstanding immediately prior to the Merger was converted into the right to receive approximately 3.1624 shares of Tocagen common stock (before giving effect to the reverse split). All share and per share amounts have been retrospectively adjusted to give effect to the exchange of Forte Subsidiary common stock and the reverse split of Tocagen common stock. The par value per share of our capital stock was not adjusted as a result of the stock split. Immediately prior to the closing of the Merger, Tocagen changed its name to Forte Biosciences, Inc. The Company’s common stock is traded on the Nasdaq stock exchange under the ticker symbol “FBRX.” Immediately following the Merger, the former Forte Subsidiary and Tocagen security holders owned approximately 84.7% and 15.3% of the number of shares of the Company’s common stock, respectively.

Prior to the Merger, Forte Subsidiary was incorporated as Forte Biosciences, Inc. under the laws of the State of Delaware on May 3, 2017 as a privately-held company. Forte Biosciences, Inc. was renamed Forte Subsidiary, Inc. in connection with the Merger.

The Merger was accounted for as a reverse asset acquisition. Forte Subsidiary is deemed to be the accounting acquirer for accounting purposes and Tocagen the accounting acquiree (Note 4). Accordingly, for accounting purposes: (i) the Merger was treated as the equivalent of Forte Subsidiary issuing stock to acquire the net assets of Tocagen, (ii) the transaction price was allocated over the acquired Tocagen net assets based upon their relative fair value at the time of closing, (iii) the reported historical operating results of the combined company prior to the Merger are those of Forte Subsidiary and not of Tocagen, and (iv) for periods prior to the transaction, shareholders’ authorized capital of the combined company is presented using the historical authorized capital of Tocagen.

On February 12, 2021, the Company incorporated Forte Biosciences Emerald Limited in Dublin, Ireland, for the purpose of potentially undertaking clinical trials in the European Union.

Liquidity and Risks

The accompanying condensed consolidated financial statements have been prepared assuming that the Company will continue as a going concern, which contemplates the realization of assets and the settlement of liabilities and commitments in the normal course of business. The condensed consolidated financial statements do not reflect any adjustments relating to the recoverability and reclassification of assets and liabilities that might be necessary if the Company is unable to continue as a going concern. Since inception, the Company has incurred losses and negative cash flows from operations. As of September 30, 2021, the Company had an accumulated deficit

of $69.8 million. The Company used $13.1 million of cash in operating activities during the nine months ended September 30, 2021. Management expects to continue to incur additional losses in the foreseeable future as the Company explores its available strategic alternatives to maximize shareholder value following the announcement on September 2, 2021 of the unfavorable clinical trial results of FB-401.

The Company had cash and cash equivalents of approximately $45.7 million as of September 30, 2021. The Company’s cash and cash equivalents are held at financial institutions and exceed federally insured limits. The Company believes that its existing cash and cash equivalents will be sufficient to allow the Company to fund its operations for at least 12 months from the filing date of this Form 10-Q.

The Company will continue to need to raise additional capital or obtain financing from other sources. Management may fund future operations through the sale of equity and debt financings and may also seek additional capital through arrangements with strategic partners or other sources. There can be no assurance that additional funding will be available on terms acceptable to the Company, if at all. If the Company is unable to raise additional funding to meet its working capital needs in the future, it may be forced to delay or reduce the scope of its research and development programs and/or limit or cease its operations.

There are numerous risks and uncertainties associated with pharmaceutical development and the Company is unable to predict the timing or amount of increased expenses on the development of future product candidates or when or if it will start to generate revenues. Even if the Company does generate revenues, it may not be able to achieve or maintain profitability. If the Company fails to become profitable or is unable to sustain profitability on a continuing basis, then it may be unable to continue its operations at planned levels and may be forced to reduce its operations.

The pandemic caused by outbreaks of new strains of coronaviruses, or COVID-19 and its variants, has resulted, and may to continue to result, in significant national and global economic disruption and may adversely affect the Company’s operations. The Company is actively monitoring the impact of COVID-19 and the possible effects on its financial condition, liquidity, operations, suppliers, industry, and workforce. However, the full extent, consequences, and duration of the COVID-19 pandemic and the resulting impact on the Company cannot currently be predicted. The Company will continue to evaluate the impact that these events could have on its operations, financial position, results of operations and cash flows during the remainder of 2021.