Cover - shares	3 Months Ended
	Mar. 31, 2022	May 06, 2022
Cover [Abstract]
Document Type	10-Q
Document Period End Date	Mar. 31, 2022
Current Fiscal Year End Date	--12-31
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	646
Local Phone Number	905-3974
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	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		42,511,357
Entity Central Index Key	0001816590
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1
Amendment Flag	false
Document Quarterly Report	true