Collaboration Agreements - Additional Information (Details) - Surface Oncology, Inc.	1 Months Ended	3 Months Ended
	Nov. 30, 2017 TargetAntigen	Mar. 31, 2019 USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of target antigens against which antibodies are to be identified and selected | TargetAntigen	2
Upfront payments fee received | $		$ 93,887
Minimum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Term of research program	9 months
Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Term of research program	12 months