| Cover | Aug. 16, 2023 | Jun. 30, 2023 |
| Cover [Abstract] | ||
| Document Type | 8-K | |
| Document Period End Date | Aug. 16, 2023 | |
| Entity Registrant Name | COMPASS PATHWAYS PLC | |
| Entity Incorporation, State or Country Code | X0 | |
| Entity File Number | 001-39522 | |
| Entity Address, Address Line One | 33 Broadwick Street | |
| Entity Address, City or Town | London | |
| Entity Address, Postal Zip Code | W1F 0DQ | |
| Entity Address, Country | GB | |
| Country Region | 1 | |
| City Area Code | (716) | |
| Local Phone Number | 676-6461 | |
| Written Communications | false | |
| Soliciting Material | false | |
| Pre-commencement Tender Offer | false | |
| Pre-commencement Issuer Tender Offer | false | |
| Title of 12(b) Security | American Depositary Shares, each representing one ordinary share, nominal value £0.008 per share | |
| Trading Symbol | CMPS | |
| Security Exchange Name | NASDAQ | |
| Entity Emerging Growth Company | false | |
| Amendment Flag | false | |
| Entity Central Index Key | 0001816590 |
