v3.26.1
Cover - shares
3 Months Ended
Mar. 31, 2026
May 06, 2026
Cover [Abstract]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Mar. 31, 2026  
Document Transition Report false  
Entity File Number 001-39522  
Entity Registrant Name COMPASS Pathways plc  
Entity Incorporation, State or Country Code X0  
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  
City Area Code 716  
Local Phone Number 676-6461  
Title of 12(b) Security American Depositary Shares, each representing one ordinary share, par value of £0.008 per share  
Trading Symbol CMPS  
Security Exchange Name NASDAQ  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Non-accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   134,949,320
Entity Central Index Key 0001816590  
Document Fiscal Year Focus 2026  
Document Fiscal Period Focus Q1  
Amendment Flag false  
Current Fiscal Year End Date --12-31