Nature of the Business	9 Months Ended
Sep. 30, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature of the Business	1. NATURE OF THE BUSINESS Prevail Therapeutics Inc., or the Company, was incorporated in the State of Delaware on July 6, 2017. The Company is a clinical-stage gene therapy company leveraging breakthroughs in human genetics with the goal of developing and commercializing disease-modifying AAV-based gene therapies for patients with devastating neurodegenerative diseases. Since beginning operations, the Company has devoted substantially all its efforts to organizing and staffing the Company, raising capital, establishing and protecting the Company’s intellectual property portfolio, in-licensing the rights to AAV9, developing and progressing the Company’s gene therapy product candidates through preclinical studies and initiating clinical trials, and establishing a manufacturing platform. The Company is applying a precision medicine approach to neurodegeneration by studying its gene therapies in genetically defined patient populations. The Company believes this will increase the probability of creating disease-modifying therapies that improve patients’ lives. The Company’s lead clinical-stage programs are PR001 for the treatment of Parkinson’s disease with GBA1 mutations, or PD-GBA, and neuronopathic (Type 2 or Type 3) Gaucher disease, or nGD, and PR006 for the treatment of frontotemporal dementia with GRN mutations, or FTD-GRN. The Company is also focused on developing a broad pipeline of gene therapies for a range of neurodegenerative diseases, including PR004 for the treatment of synucleinopathies, and other programs. The Company is subject to a number of risks common to early-stage companies in the biotechnology industry. Principal among these risks are the uncertainties in the development process, development of the same or similar technological innovations by competitors, protection of proprietary technology, dependence on key personnel, compliance with government regulations and approval requirements, and the need to obtain additional financing to fund operations. Product candidates currently under development will require significant additional research and development efforts, including extensive pre-clinical and clinical testing and regulatory approval, prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel infrastructure, and extensive compliance-reporting capabilities. There can be no assurance that the Company’s research and development will be successfully completed, that adequate protection for the Company’s technology will be obtained, that any products developed will obtain necessary government regulatory approval, or that any approved products will be commercially viable. The Company operates in an environment of rapid change in technology and substantial competition from pharmaceutical and biotechnology companies. In addition, the Company is dependent upon the services of its employees, consultants and contractors. Stock Split - In June 2019, the Board of Directors of the Company approved a 1.62-for-one forward stock-split of the Company’s outstanding shares of common stock, convertible preferred stock and options outstanding and available for future issuance. The stock split became effective on June 7, 2019. Accordingly, all share and per share amounts for all periods presented in the accompanying financial statements and notes thereto have been retroactively adjusted, where applicable, to reflect this forward stock split. Shares of common stock underlying outstanding stock options and other equity instruments were proportionately increased and the respective per share value and exercise prices, if applicable, were proportionately decreased in accordance with the terms of the agreements governing such securities. Initial Public Offering - In June 2019, the Company completed its initial public offering, or IPO, whereby the Company sold an aggregate of 7,353,000 shares of its common stock at a price of $17.00 per share. The shares began trading on The Nasdaq Global Select Market on June 20, 2019. The aggregate net proceeds received by the Company from the offering were approximately $113.0 million, after deducting underwriting discounts and commissions and offering expenses payable by the Company of $12.0 million. Upon the closing of the IPO, all outstanding shares of redeemable convertible preferred stock converted into 19,435,131 shares of common stock. Additionally, the Company is authorized to issue 200,000,000 shares of common stock and 10,000,000 shares of preferred stock. On June 24, 2019, the Company filed an Amended and Restated Certificate of Incorporation with the Secretary of State of the State of Delaware, in connection with the closing of the IPO. Liquidity and Capital Resources- Since its inception, the Company has incurred operating losses and has consistently used cash to fund operations. The Company has not recognized any revenue to date, devoting its efforts and capital resources to research and development of its product candidates. The Company’s activities have been primarily funded by the sale of shares of convertible preferred stock and common stock (see Note 8). The Company manages its capital resources to ensure the Company will continue as a going concern while maximizing the return to stockholders through the optimization of the debt and equity balances. The Company’s cash and cash equivalents as of September 30, 2020 and December 31, 2019 were $81.7 million and $168.1 million respectively and the Company held investments of $32.6 million as of September 30, 2020 that are available to be sold for cash. In March 2019, the Company raised an aggregate of $49.8 million of net proceeds from its Series B Preferred Stock financing. In June 2019, the Company completed its IPO whereby the Company sold an aggregate of 7,353,000 shares of its common stock for aggregate net proceeds of approximately $113.0 million. The Company estimates that its cash and cash equivalents and available-for-sale investments balances as of September 30, 2020, will be sufficient to enable it to fund its operating expenses and capital expenditure requirements for at least 12 months from the issuance date of these financial statements. This estimate is based on assumptions that may prove to be incorrect, and the Company could use its available capital resources sooner than currently expected. Changing circumstances could cause the Company to consume capital resources sooner than currently anticipated, and the Company may need to spend more than currently planned due to circumstances beyond its control.

Nature of the Business

9 Months Ended

Sep. 30, 2020

Organization Consolidation And Presentation Of Financial Statements [Abstract]

1. NATURE OF THE BUSINESS

Prevail Therapeutics Inc., or the Company, was incorporated in the State of Delaware on July 6, 2017. The Company is a clinical-stage gene therapy company leveraging breakthroughs in human genetics with the goal of developing and commercializing disease-modifying AAV-based gene therapies for patients with devastating neurodegenerative diseases. Since beginning operations, the Company has devoted substantially all its efforts to organizing and staffing the Company, raising capital, establishing and protecting the Company’s intellectual property portfolio, in-licensing the rights to AAV9, developing and progressing the Company’s gene therapy product candidates through preclinical studies and initiating clinical trials, and establishing a manufacturing platform. The Company is applying a precision medicine approach to neurodegeneration by studying its gene therapies in genetically defined patient populations. The Company believes this will increase the probability of creating disease-modifying therapies that improve patients’ lives. The Company’s lead clinical-stage programs are PR001 for the treatment of Parkinson’s disease with GBA1 mutations, or PD-GBA, and neuronopathic (Type 2 or Type 3) Gaucher disease, or nGD, and PR006 for the treatment of frontotemporal dementia with GRN mutations, or FTD-GRN. The Company is also focused on developing a broad pipeline of gene therapies for a range of neurodegenerative diseases, including PR004 for the treatment of synucleinopathies, and other programs.

The Company is subject to a number of risks common to early-stage companies in the biotechnology industry. Principal among these risks are the uncertainties in the development process, development of the same or similar technological innovations by competitors, protection of proprietary technology, dependence on key personnel, compliance with government regulations and approval requirements, and the need to obtain additional financing to fund operations. Product candidates currently under development will require significant additional research and development efforts, including extensive pre-clinical and clinical testing and regulatory approval, prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel infrastructure, and extensive compliance-reporting capabilities.

There can be no assurance that the Company’s research and development will be successfully completed, that adequate protection for the Company’s technology will be obtained, that any products developed will obtain necessary government regulatory approval, or that any approved products will be commercially viable. The Company operates in an environment of rapid change in technology and substantial competition from pharmaceutical and biotechnology companies. In addition, the Company is dependent upon the services of its employees, consultants and contractors.

Stock Split - In June 2019, the Board of Directors of the Company approved a 1.62-for-one forward stock-split of the Company’s outstanding shares of common stock, convertible preferred stock and options outstanding and available for future issuance. The stock split became effective on June 7, 2019. Accordingly, all share and per share amounts for all periods presented in the accompanying financial statements and notes thereto have been retroactively adjusted, where applicable, to reflect this forward stock split. Shares of common stock underlying outstanding stock options and other equity instruments were proportionately increased and the respective per share value and exercise prices, if applicable, were proportionately decreased in accordance with the terms of the agreements governing such securities.

Initial Public Offering - In June 2019, the Company completed its initial public offering, or IPO, whereby the Company sold an aggregate of 7,353,000 shares of its common stock at a price of $17.00 per share. The shares began trading on The Nasdaq Global Select Market on June 20, 2019. The aggregate net proceeds received by the Company from the offering were approximately $113.0 million, after deducting underwriting discounts and commissions and offering expenses payable by the Company of $12.0 million. Upon the closing of the IPO, all outstanding shares of redeemable convertible preferred stock converted into 19,435,131 shares of common stock. Additionally, the Company is authorized to issue 200,000,000 shares of common stock and 10,000,000 shares of preferred stock. On June 24, 2019, the Company filed an Amended and Restated Certificate of Incorporation with the Secretary of State of the State of Delaware, in connection with the closing of the IPO.

Liquidity and Capital Resources- Since its inception, the Company has incurred operating losses and has consistently used cash to fund operations. The Company has not recognized any revenue to date, devoting its efforts and capital resources to research and development of its product candidates. The Company’s activities have been primarily funded by the sale of shares of convertible preferred stock and common stock (see Note 8). The Company manages its capital resources to ensure the Company will continue as a going concern while maximizing the return to stockholders through the optimization of the debt and equity balances.

The Company’s cash and cash equivalents as of September 30, 2020 and December 31, 2019 were $81.7 million and $168.1 million respectively and the Company held investments of $32.6 million as of September 30, 2020 that are available to be sold for cash. In March 2019, the Company raised an aggregate of $49.8 million of net proceeds from its Series B Preferred Stock financing. In June 2019, the Company completed its IPO whereby the Company sold an aggregate of 7,353,000 shares of its common stock for aggregate net proceeds of approximately $113.0 million. The Company estimates that its cash and cash equivalents and available-for-sale investments balances as of September 30, 2020, will be sufficient to enable it to fund its operating expenses and capital expenditure requirements for at least 12 months from the issuance date of these financial statements. This estimate is based on assumptions that may prove to be incorrect, and the Company could use its available capital resources sooner than currently expected. Changing circumstances could cause the Company to consume capital resources sooner than currently anticipated, and the Company may need to spend more than currently planned due to circumstances beyond its control.