Goodwill and Intangible Assets - Gross Carrying Amounts and Net Book Values of Intangible Assets (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 3,249,201	$ 3,408,566
Accumulated Amortization	(605,488)	(578,017)
Total	2,643,713	2,830,549
Indefinite-lived Intangible Assets [Line Items]
Gross Carrying Amount - Total Intangible Assets	3,392,769	3,557,144
Net Book Value - Total Intangible Assets	2,787,281	2,979,127
Acquired IPR&D assets
Indefinite-lived Intangible Assets [Line Items]
In-process research and development	$ 143,568	148,578
Acquired developed technologies
Finite-Lived Intangible Assets [Line Items]
Remaining Weighted- Average Useful Life (In years)	14 years 7 months
Gross Carrying Amount	$ 3,122,811	3,392,832
Accumulated Amortization	(590,198)	(562,473)
Total	2,532,613	2,830,359
Priority review voucher
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	111,100	0
Accumulated Amortization	0	0
Total	$ 111,100	0
Manufacturing contracts
Finite-Lived Intangible Assets [Line Items]
Remaining Weighted- Average Useful Life (In years)	0 years
Gross Carrying Amount	$ 12,391	12,824
Accumulated Amortization	(12,391)	(12,634)
Total	$ 0	190
Trademarks
Finite-Lived Intangible Assets [Line Items]
Remaining Weighted- Average Useful Life (In years)	0 years
Gross Carrying Amount	$ 2,899	2,910
Accumulated Amortization	(2,899)	(2,910)
Total	$ 0	$ 0