License and Asset Acquisitions - Schedule of IPR&D Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Acquired Finite-Lived Intangible Assets [Line Items]
Total in process research and development	$ 23,380	$ 3,600	$ 49,659
Seralutinib
Acquired Finite-Lived Intangible Assets [Line Items]
Total in process research and development	5,000	0	0
GB004
Acquired Finite-Lived Intangible Assets [Line Items]
Total in process research and development	15,000	0	20,000
GB1275
Acquired Finite-Lived Intangible Assets [Line Items]
Total in process research and development	0	1,000	7,501
GB001
Acquired Finite-Lived Intangible Assets [Line Items]
Total in process research and development	0	0	19,148
Other preclinical programs
Acquired Finite-Lived Intangible Assets [Line Items]
Total in process research and development	$ 3,380	$ 2,600	$ 3,010