Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2022	Mar. 10, 2023	Jun. 30, 2022
Document Information [Line Items]
Entity Central Index Key	0001738021
Entity Registrant Name	Compass Therapeutics, Inc.
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2022
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2022
Document Transition Report	false
Entity File Number	000-55939
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	82-4876496
Entity Address, Address Line One	80 Guest Street, Suite 601
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02135
City Area Code	617
Local Phone Number	500-8099
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Trading Symbol	CMPX
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	true
Entity Ex Transition Period	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Public Float			$ 184,000,000
Entity Common Stock, Shares Outstanding		126,507,473
Auditor Firm ID	596
Auditor Name	CohnReznick LLP
Auditor Location	Melville, NY U.S.A.