Collaboration Agreements - Additional Information (Details)	1 Months Ended	3 Months Ended
	Nov. 30, 2017 TargetAntigen	Mar. 31, 2021 USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue		$ 850,000
Surface Oncology, Inc.
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of target antigens against which antibodies are to be identified and selected | TargetAntigen	2
Revenue		850,000
Surface Oncology, Inc. | Exclusive Product License
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue		850,000
Surface Oncology, Inc. | License
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue		$ 850,000
Surface Oncology, Inc. | Minimum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Term of research program	9 months
Surface Oncology, Inc. | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Term of research program	12 months