Licenses, Asset Acquisitions and Contingent Consideration - Schedule of IPR&D Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Acquired Finite Lived Intangible Assets [Line Items]
Total in process research and development	$ 15,000	$ 1,000	$ 17,805	$ 2,000
GB004
Acquired Finite Lived Intangible Assets [Line Items]
Total in process research and development	$ 15,000		15,000
Other Programs
Acquired Finite Lived Intangible Assets [Line Items]
Total in process research and development			$ 2,805	1,000
GB1275
Acquired Finite Lived Intangible Assets [Line Items]
Total in process research and development		$ 1,000		$ 1,000