Nature of Business	12 Months Ended
Nature of Business	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Business	Nature of Business COMPASS Pathways plc, or the Company, is a mental health care company dedicated to accelerating patient access to evidence-based innovation in mental health. The Company is developing its investigational COMP360 psilocybin therapy through late-stage clinical trials in Europe and North America for patients with treatment-resistant depression. The Company is subject to risks and uncertainties common to clinical 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 intellectual property and technology, compliance with government regulations and the ability to secure additional capital to fund operations. Therapeutic 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 capital, adequate personnel and infrastructure and extensive compliance-reporting capabilities. Even if the Company’s therapeutic development efforts are successful, it is uncertain when, if ever, the Company will realize revenue from sales. The Company has funded its operations primarily with proceeds from the sale of its convertible preferred shares, the issuance of convertible notes, and more recently through the sale of American Depository Shares, or ADSs, in connection with the Company’s initial public offering, or the IPO, in September 2020, and its $154.8 million May 2021 follow-on offering. On October 8, 2021, the Company entered into a Sales Agreement with Cowen and Company, LLC, or Cowen, under which the Company may issue and sell from time to time up to $150.0 million of its ADSs, each representing one ordinary share, through Cowen as the sales agent. Sales of the Company’s ADSs, if any, will be made at market prices. On December 14, 2022, under our at-the-market offering we sold 44,416 ADSs at $10.53 per ADS. The Company has incurred recurring losses since its inception, including net losses of $91.5 million and $71.7 million for the years ended December 31, 2022 and 2021, respectively. In addition, as of December 31, 2022, the Company had an accumulated deficit of $261.1 million. The Company expects to continue to generate operating losses for the foreseeable future. The Company believes the cash and cash equivalents on hand as of December 31, 2022 of $143.2 million will be sufficient to fund its operating expenses and capital expenditure requirements for at least the next twelve months, including progressing our Phase 3 clinical program, our Phase 2 studies in anorexia nervosa and PTSD and costs associated with operating as a public company. The accompanying financial statements have been prepared on a going concern basis, which contemplates the realization of assets and satisfaction of liabilities in the ordinary course of business. We will need substantial additional funding to complete the development and commercialization of our Phase 3 clinical program, and our Phase 2 studies in anorexia nervosa and PTSD. The Company’s inability to raise capital as and when needed could have a negative impact on its financial condition and ability to pursue its business strategies. There can be no assurance that the current operating plan will be achieved or that additional funding will be available on terms acceptable to the Company, or at all. The future viability of the Company is dependent on its ability to raise additional capital to finance its operations. The Company may raise additional capital through a combination of equity offerings, debt financings, collaborations, and other strategic transactions, including marketing, distribution or licensing arrangements. There can be no assurance that additional funding will be available on terms acceptable to the Company, on a timely basis or at all. The failure of the Company to obtain sufficient funds on acceptable terms when needed could have a material adverse effect on the Company’s business, results of operations, and financial conditions. The COVID-19 pandemic and policies and regulations implemented by governments in response to the COVID-19 pandemic, most of which have been lifted, have had a significant impact, both directly and indirectly, on global businesses and commerce. For example, although restrictions in the United Kingdom and the United States have generally been lifted, additional indirect effects such as worker shortages and supply chain constraints continue to impact segments of the economy. The future extent of the impact of the COVID-19 pandemic on our preclinical studies or clinical trial operations, our supply chain and manufacturing and our office-based business operations or any of the third parties on whom it relies or with whom the Company conducts business, such as CROs or CMOs, will depend on future developments, which remain highly uncertain and cannot be predicted with confidence, such as the duration of the pandemic, the emergence of additional or more infectious variants, or the effectiveness of actions to contain and treat coronavirus.