Related Party Transactions - Additional Information (Details)		1 Months Ended	3 Months Ended
	Jan. 21, 2020 USD ($) $ / shares shares	Nov. 30, 2017 TargetAntigen	Mar. 31, 2020 USD ($) shares	Mar. 31, 2019 USD ($)	Dec. 31, 2019 shares
Related Party Transaction [Line Items]
Rent expense incurred under operating lease			$ 42,000	$ 42,000
Gross proceeds from issuance of common stock			$ 5,000,000
Common stock, shares issued | shares			16,377,587		14,887,999
Dr. Maurice Zauderer
Related Party Transaction [Line Items]
Gross proceeds from issuance of common stock	$ 4,999,999
Common stock, shares issued | shares	982,318
Chief Executive Officer
Related Party Transaction [Line Items]
Gross proceeds from issuance of common stock	$ 499,996
Common stock, shares issued | shares	98,231
Jacob Frieberg
Related Party Transaction [Line Items]
Gross proceeds from issuance of common stock	$ 199,996
Common stock, shares issued | shares	39,292
Stock Purchase Agreement
Related Party Transaction [Line Items]
Sale of stock, transaction date	Jan. 21, 2020
Stock Purchase Agreement | Common Stock
Related Party Transaction [Line Items]
Aggregate number of shares issued | shares	1,468,563
Shares issued, price per share | $ / shares	$ 5.09
Gross proceeds from issuance of common stock	$ 7,500,000
Surface Oncology, Inc.
Related Party Transaction [Line Items]
Number of target antigens against which antibodies are to be identified and selected | TargetAntigen		2
Service fee payment received				$ 93,887