Cover - shares	3 Months Ended
	Mar. 31, 2023	May 01, 2023
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2023
Document Transition Report	false
Entity File Number	001-38459
Entity Registrant Name	SURFACE ONCOLOGY, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	46-5543980
Entity Address, Address Line One	50 Hampshire Street
Entity Address, Address Line Two	8th Floor
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02139
City Area Code	617
Local Phone Number	714-4096
Title of 12(b) Security	Common stock, $0.0001
Trading Symbol	SURF
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	true
Entity Ex Transition Period	true
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		60,716,873
Amendment Flag	false
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q1
Entity Central Index Key	0001718108
Current Fiscal Year End Date	--12-31