License, Research and Collaboration Agreements - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Research and development	$ 3,670,000	$ 5,979,000	$ 10,498,000	$ 19,146,000
Adimab Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration agreement date			Oct. 16, 2014
Future milestone payments	2,000,000		$ 2,000,000
Milestone payments	0		0
Research and development milestone payments		1,000,000		1,500,000
Other License and Research Agreements
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Cash payment for license agreement	63,000		200,000
Research and development	64,000	$ 79,000	200,000	$ 400,000
Clinical and regulatory milestone payments	$ 500,000		$ 500,000