Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)	1 Months Ended		3 Months Ended
	Jan. 31, 2018	Oct. 31, 2017	Mar. 31, 2021
Summary Of Significant Accounting Policies [Line Items]
Increase in expected cost percentage			4.00%
Reduced revenue			$ 4,600,000
Collaboration revenue			4,100,000
Deferred revenue			128,200,000
AbbVie Biotechnology Limited
Summary Of Significant Accounting Policies [Line Items]
Upfront payments		$ 205,000,000.0
Upfront payment received	$ 200,000,000	5,000,000.0
Exclusive option rights exercised for each program		250,000,000.0
AbbVie Biotechnology Limited | Maximum
Summary Of Significant Accounting Policies [Line Items]
Additional milestone payments per program related to initiation of certain clinical studies and regulatory approval		$ 242,800,000
Innovent
Summary Of Significant Accounting Policies [Line Items]
Collaboration revenue			0
Development milestone			11,500,000
Sales milestone			112,500,000
Money Market Funds
Summary Of Significant Accounting Policies [Line Items]
Unrealized gains or loss on money market funds			$ 0