Nature of the business	6 Months Ended
Nature of the business	Sep. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of the business	Nature of the business Replimune Group, Inc. (the “Company”) is a clinical-stage biotechnology company committed to applying its leading expertise in the field of oncolytic immunotherapy to transform the lives of cancer patients through its novel tumor-directed oncolytic immunotherapies. The Company's proprietary tumor-directed oncolytic immunotherapy product candidates are designed and intended to maximally activate the immune system against cancer. Replimune Group, Inc., whose predecessor was founded in 2015, is the parent company of its wholly owned, direct and indirect subsidiaries: Replimune Limited (“Replimune UK”); Replimune, Inc. (“Replimune US”); Replimune Securities Corporation; and Replimune (Ireland) Limited. The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry, including, but not limited to, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, third-party intellectual property, compliance with government regulations and the ability to secure additional capital to fund operations. Product candidates currently under development will require significant additional research and development efforts, including preclinical and clinical testing and regulatory approval, prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel and infrastructure and extensive compliance and reporting capabilities. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales. Basis of presentation The accompanying consolidated financial statements have been prepared on the basis of continuity of operations, realization of assets and the satisfaction of liabilities and commitments in the ordinary course of business. The Company has incurred recurring losses since its inception, including net losses of $43.1 million and $29.4 million for the three months ended September 30, 2022 and 2021, respectively and net losses of $85.4 million and $56.7 million for the six months ended September 30, 2022 and 2021, respectively. In addition, as of September 30, 2022, the Company had an accumulated deficit of $396.6 million. The Company expects to continue to generate operating losses for the foreseeable future. As of the issuance date of these consolidated financial statements, the Company expects that its cash and cash equivalents and short-term investments will be sufficient to fund its operating expenses and capital expenditure requirements through at least 12 months from the issuance of these consolidated financial statements. Impact of the COVID-19 coronavirus In December 2019, a novel strain of coronavirus, which causes the disease known as COVID-19, was reported to have surfaced in Wuhan, China. Since then, COVID-19 coronavirus has spread globally. In March 2020, the World Health Organization declared the COVID-19 outbreak a pandemic and the U.S. government imposed travel restrictions on travel between the United States, Europe and certain other countries. The impact of this pandemic has been, and may continue to be, extensive in many aspects of society, which has resulted, and may continue to result, in significant disruptions to the global economy as well as businesses and capital markets around the world. The Company is continuing to generally monitor the spread of COVID-19 and, throughout the pandemic, has implemented measures designed to comply with applicable federal, state and local guidelines, as well as care for the Company's employee's health and well-being. The Company will continue to examine its protocols as the pandemic and health guidance evolves. The COVID-19 pandemic continues to affect the United States and global economies and has affected and may continue to affect the Company's operations and those of third parties on which it relies, including by causing disruptions in our raw material and supply of other materials, the manufacturing of its product candidates and its developing commercialization processes. However, the extent of these delays is currently unknown and has and will likely continue to vary. In addition, the Company may incur unforeseen costs as a result of disruptions in raw material supplies, clinical product supplies, and preclinical studies or clinical trial delays. The full extent to which the COVID-19 pandemic will directly or indirectly impact the Company's business, results of operations and financial condition will depend on future developments that are highly uncertain and cannot be accurately predicted, including new information that may emerge concerning COVID-19, the actions taken in an effort to contain it or to potentially treat or continue to vaccinate against COVID-19 and the economic impact on local, regional, national and international markets. The Company continues to monitor this situation and the possible effects on its financial condition, liquidity, operations, suppliers, supplies, industry and workforce.