Cover - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Feb. 22, 2023	Jun. 30, 2022
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Current Fiscal Year End Date	--12-31
Document Period End Date	Dec. 31, 2022
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 Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
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
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Public Float			$ 247.2
Entity Common Stock, Shares Outstanding		42,763,816
Documents Incorporated by Reference	Portions of the Registrant’s Proxy Statement for the 2023 Annual Meeting of Shareholders are incorporated herein by reference into Part III of this Annual Report on Form 10-K to the extent stated herein. Such proxy statement will be filed with the Securities and Exchange Commission within 120 days of the Registrant’s fiscal year ending December 31, 2022.
Entity Central Index Key	0001816590
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY
Amendment Flag	false