Research and Development Agreements - Schedule of Research and Development Revenue from Related Party Relates to Revenue from Research and Development Agreements (Detail)

v3.20.4

Research and Development Agreements - Schedule of Research and Development Revenue from Related Party Relates to Revenue from Research and Development Agreements (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Revenue Recognition [Line Items]
Total research and development revenue, related party	$ 15,635	$ 19,499
Millennium Pharmaceuticals Inc
Revenue Recognition [Line Items]
Total research and development revenue, related party	6,567	19,499
Millennium Pharmaceuticals Inc | Takeda Individual Project Agreement
Revenue Recognition [Line Items]
Total research and development revenue, related party	0	48
Millennium Pharmaceuticals Inc | Takeda Development Agreement
Revenue Recognition [Line Items]
Total research and development revenue, related party	6,068	18,468
Millennium Pharmaceuticals Inc | Takeda Multi Target Agreement
Revenue Recognition [Line Items]
Total research and development revenue, related party	$ 499	$ 983