Goodwill and Intangible Assets - Gross Carrying Amounts and Net Book Values of Intangible Assets (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Jan. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 3,340,242			$ 3,292,501
Accumulated Amortization	(1,099,135)			(990,850)
Total	2,241,107			2,301,651
Intangible Assets [Line Items]
Gross Carrying Amount - Total Intangible Assets	3,340,242			3,431,827
Net Book Value - Total Intangible Assets	2,241,107			2,440,977
Acquired IPR&D assets
Intangible Assets [Line Items]
In-process research and development	0			139,326
Impairment of intangible assets	$ 136,100
Acquired developed technologies
Finite-Lived Intangible Assets [Line Items]
Remaining Weighted- Average Useful Life (In years)	12 years 8 months 12 days
Gross Carrying Amount	$ 3,324,806			3,166,485
Accumulated Amortization	(1,083,699)			(864,834)
Total	$ 2,241,107			2,301,651
Manufacturing contracts
Finite-Lived Intangible Assets [Line Items]
Remaining Weighted- Average Useful Life (In years)	0 years
Gross Carrying Amount	$ 12,533			12,025
Accumulated Amortization	(12,533)			(12,025)
Total	$ 0			0
Trademarks
Finite-Lived Intangible Assets [Line Items]
Remaining Weighted- Average Useful Life (In years)	0 years
Gross Carrying Amount	$ 2,903			2,890
Accumulated Amortization	(2,903)			(2,890)
Total	$ 0			0
Priority review voucher
Finite-Lived Intangible Assets [Line Items]
Remaining Weighted- Average Useful Life (In years)	0 years
Gross Carrying Amount	$ 0			111,101
Accumulated Amortization	0			(111,101)
Total	$ 0			$ 0
FDA Approval Of Zepzelca
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount		$ 100,000
European Marketing Authorization Of Sunosi
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount			$ 13,000