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Licenses, Asset Acquisitions and Contingent Consideration - Schedule of IPR&D Expense (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Jun. 30, 2018	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Acquired Finite-Lived Intangible Assets [Line Items]
Total in process research and development	$ 20,000	$ 275	$ 0	$ 18,080	$ 2,000
GB001
Acquired Finite-Lived Intangible Assets [Line Items]
Total in process research and development		0	0	0	0
GB002
Acquired Finite-Lived Intangible Assets [Line Items]
Total in process research and development		0	0	0	0
GB004
Acquired Finite-Lived Intangible Assets [Line Items]
Total in process research and development		275	0	15,275	0
GB1275
Acquired Finite-Lived Intangible Assets [Line Items]
Total in process research and development		0	0	0	1,000
Other Programs
Acquired Finite-Lived Intangible Assets [Line Items]
Total in process research and development		$ 0	$ 0	$ 2,805	$ 1,000

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The amount of purchased research and development assets that are acquired in a business combination have no alternative future use and are therefore written off in the period of acquisition.

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