Goodwill and Intangible Assets - Gross Carrying Amounts and Net Book Values of Intangible Assets (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 3,310,557	$ 3,236,894
Accumulated Amortization	(763,753)	(647,565)
Total	2,546,804	2,589,329
Indefinite-lived Intangible Assets [Line Items]
Gross Carrying Amount - Total Intangible Assets	3,451,694	3,378,899
Net Book Value - Total Intangible Assets	2,687,941	2,731,334
Acquired IPR&D assets
Indefinite-lived Intangible Assets [Line Items]
In-process research and development	$ 141,137	142,005
Acquired developed technologies
Finite-Lived Intangible Assets [Line Items]
Remaining Weighted- Average Useful Life (In years)	13 years 7 months 6 days
Gross Carrying Amount	$ 3,184,381	3,110,641
Accumulated Amortization	(748,678)	(632,413)
Total	2,435,703	2,478,228
Priority review voucher
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	111,101	111,101
Accumulated Amortization	0	0
Total	$ 111,101	111,101
Manufacturing contracts
Finite-Lived Intangible Assets [Line Items]
Remaining Weighted- Average Useful Life (In years)	0 years
Gross Carrying Amount	$ 12,181	12,256
Accumulated Amortization	(12,181)	(12,256)
Total	$ 0	0
Trademarks
Finite-Lived Intangible Assets [Line Items]
Remaining Weighted- Average Useful Life (In years)	0 years
Gross Carrying Amount	$ 2,894	2,896
Accumulated Amortization	(2,894)	(2,896)
Total	$ 0	$ 0