Organization and Description of Business Operations	9 Months Ended
Sep. 30, 2022
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization and Description of Business Operations	Note 1—Organization and Description of Business Operations Taysha Gene Therapies, Inc. (the “Company” or “Taysha”) was originally formed under the laws of the State of Texas on September 20, 2019 (“Inception”). Taysha converted to a Delaware corporation on February 13, 2020, which had no impact to the Company’s par value or issued and authorized capital structure. Taysha is a patient-centric gene therapy company focused on developing and commercializing AAV-based gene therapies for the treatment of monogenic diseases of the central nervous system in both rare and large patient populations. Sales Agreement On October 5, 2021, the Company entered into a Sales Agreement (the “Sales Agreement”) with SVB Securities LLC (f/k/a SVB Leerink LLC) and Wells Fargo Securities, LLC (collectively, the “Sales Agents”), pursuant to which the Company may issue and sell, from time to time in its sole discretion, shares of its common stock having an aggregate offering price of up to $150.0 million through the Sales Agents. In March 2022, the Company amended the Sales Agreement to, among other things, include Goldman Sachs & Co. LLC as an additional Sales Agent. The Sales Agents may sell common stock by any method permitted by law deemed to be an “at-the-market offering” as defined in Rule 415(a)(4) of the Securities Act, including sales made directly on or through the Nasdaq Global Select Market or any other existing trade market for the common stock, in negotiated transactions at market prices prevailing at the time of sale or at prices related to prevailing market prices, or any other method permitted by law. The Sales Agents are entitled to receive 3.0% of the gross sales price per share of common stock sold under the Sales Agreement. In April 2022, the Company sold 2,000,000 shares of common stock under the Sales Agreement and received $11.6 million in net proceeds. No other shares of common stock have been issued and sold pursuant to the Sales Agreement as of September 30, 2022. Liquidity and Capital Resources The accompanying condensed consolidated financial statements are prepared in accordance with generally accepted accounting principles applicable to a going concern, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. Pursuant to ASC 205, Presentation of Financial Statements, the Company is required to and does evaluate at each annual and interim period whether there are conditions or events, considered in the aggregate, that raise substantial doubt about its ability to continue as a going concern within one year after the date that the consolidated financial statements are issued. In its Quarterly Report on Form 10-Q for the quarter ended June 30, 2022, the Company concluded that there was insufficient funding available to allow the Company to fund its currently planned research and discovery programs and the build-out of its GMP manufacturing facility for a period exceeding one year from the filing of those financial statements, and that those conditions raised substantial doubt about the Company’s ability to continue as a going concern. In October 2022, the Company entered into a securities purchase agreement (the “Securities Purchase Agreement”) and an option agreement (the “Option Agreement,” together with the Securities Purchase Agreement the “Astellas Transactions”) with Audentes Therapeutics, Inc. (d/b/a Astellas Gene Therapy) (“Astellas”), pursuant to which the Company agreed to issue and sell 7,266,342 shares of its common stock for aggregate proceeds of $30.0 million and received a one-time payment in the amount of $20.0 million (the “Upfront Payment”), respectively, for total gross proceeds of $50.0 million. Also in October 2022, the Company entered into an underwriting agreement (the “Underwriting Agreement”) with Goldman Sachs & Co. LLC (the "Underwriter”) to issue and sell 14,000,000 shares of common stock for at a price of $2.00 per share. The Underwriter has an option, for a period of 30 days, to purchase up to an additional 2,100,000 shares of the Company’s common stock at a price of $1.88 per share. The net proceeds are expected be approximately $25.6 million, or approximately $29.6 million if the Underwriter exercises in full its option to purchase additional shares of Common Stock, in each case after deducting underwriting discounts and commissions and estimated offering expenses. See Note 12 for additional information. The Company has concluded that these additional cash flows provide the Company with sufficient liquidity to satisfy its obligations for at least twelve months following the date of the issuance of these condensed consolidated financial statements. Accordingly, the Company has concluded that there is no longer substantial doubt about the Company’s ability to continue as a going concern. The Company has incurred operating losses since inception and expects to continue to incur significant operating losses for the foreseeable future and may never become profitable. As of September 30, 2022, the Company had an accumulated deficit of $345.9 million. Losses are expected to continue as the Company continues to invest in its research and development activities. Future capital requirements will depend on many factors, including the timing and extent of spending on research and development and the market acceptance of the Company’s products. The Company will need to obtain additional financing in order to complete clinical studies and launch and commercialize any product candidates for which it receives regulatory approval. There can be no assurance that such financing will be available or will be on terms acceptable to the Company.

Organization and Description of Business Operations

9 Months Ended

Sep. 30, 2022

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Organization and Description of Business Operations

Note 1—Organization and Description of Business Operations

Taysha Gene Therapies, Inc. (the “Company” or “Taysha”) was originally formed under the laws of the State of Texas on September 20, 2019 (“Inception”). Taysha converted to a Delaware corporation on February 13, 2020, which had no impact to the Company’s par value or issued and authorized capital structure.

Taysha is a patient-centric gene therapy company focused on developing and commercializing AAV-based gene therapies for the treatment of monogenic diseases of the central nervous system in both rare and large patient populations.

Sales Agreement

On October 5, 2021, the Company entered into a Sales Agreement (the “Sales Agreement”) with SVB Securities LLC (f/k/a SVB Leerink LLC) and Wells Fargo Securities, LLC (collectively, the “Sales Agents”), pursuant to which the Company may issue and sell, from time to time in its sole discretion, shares of its common stock having an aggregate offering price of up to $150.0 million through the Sales Agents. In March 2022, the Company amended the Sales Agreement to, among other things, include Goldman Sachs & Co. LLC as an additional Sales Agent. The Sales Agents may sell common stock by any method permitted by law deemed to be an “at-the-market offering” as defined in Rule 415(a)(4) of the Securities Act, including sales made directly on or through the Nasdaq Global Select Market or any other existing trade market for the common stock, in negotiated transactions at market prices prevailing at the time of sale or at prices related to prevailing market prices, or any other method permitted by law. The Sales Agents are entitled to receive 3.0% of the gross sales price per share of common stock sold under the Sales Agreement. In April 2022, the Company sold 2,000,000 shares of common stock under the Sales Agreement and received $11.6 million in net proceeds. No other shares of common stock have been issued and sold pursuant to the Sales Agreement as of September 30, 2022.

Liquidity and Capital Resources

The accompanying condensed consolidated financial statements are prepared in accordance with generally accepted accounting principles applicable to a going concern, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business.

Pursuant to ASC 205, Presentation of Financial Statements, the Company is required to and does evaluate at each annual and interim period whether there are conditions or events, considered in the aggregate, that raise substantial doubt about its ability to continue as a going concern within one year after the date that the consolidated financial statements are issued. In its Quarterly Report on Form 10-Q for the quarter ended June 30, 2022, the Company concluded that there was insufficient funding available to allow the Company to fund its currently planned research and discovery programs and the build-out of its GMP manufacturing facility for a period exceeding one year from the filing of those financial statements, and that those conditions raised substantial doubt about the Company’s ability to continue as a going concern.

In October 2022, the Company entered into a securities purchase agreement (the “Securities Purchase Agreement”) and an option agreement (the “Option Agreement,” together with the Securities Purchase Agreement the “Astellas Transactions”) with Audentes Therapeutics, Inc. (d/b/a Astellas Gene Therapy) (“Astellas”), pursuant to which the Company agreed to issue and sell 7,266,342 shares of its common stock for aggregate proceeds of $30.0 million and received a one-time payment in the amount of $20.0 million (the “Upfront Payment”), respectively, for total gross proceeds of $50.0 million. Also in October 2022, the Company entered into an underwriting agreement (the “Underwriting Agreement”) with Goldman Sachs & Co. LLC (the "Underwriter”) to issue and sell 14,000,000 shares of common stock for at a price of $2.00 per share. The Underwriter has an option, for a period of 30 days, to purchase up to an additional 2,100,000 shares of the Company’s common stock at a price of $1.88 per share. The net proceeds are expected be approximately $25.6 million, or approximately $29.6 million if the Underwriter exercises in full its option to purchase additional shares of Common Stock, in each case after deducting underwriting discounts and commissions and estimated offering expenses. See Note 12 for additional information.

The Company has concluded that these additional cash flows provide the Company with sufficient liquidity to satisfy its obligations for at least twelve months following the date of the issuance of these condensed consolidated financial statements. Accordingly, the Company has concluded that there is no longer substantial doubt about the Company’s ability to continue as a going concern.

The Company has incurred operating losses since inception and expects to continue to incur significant operating losses for the foreseeable future and may never become profitable. As of September 30, 2022, the Company had an accumulated deficit of $345.9 million. Losses are expected to continue as the Company continues to invest in its research and development activities. Future capital requirements will depend on many factors, including the timing and extent of spending on research and development and the market acceptance of the Company’s products. The Company will need to obtain additional financing in order to complete clinical

studies and launch and commercialize any product candidates for which it receives regulatory approval. There can be no assurance that such financing will be available or will be on terms acceptable to the Company.