Collaboration Agreements - Teva Narrative (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended				9 Months Ended
	Sep. 30, 2016	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Revenues		$ 1,663,496		$ 1,500,673		$ 4,783,003	$ 4,289,780
Teva
Disaggregation of Revenue [Line Items]
Up-front payment received	$ 250,000
Revenue recognition, milestone method, revenue recognized		60,000	$ 35,000		$ 25,000
Aggregate future development milestone payments the Company is eligible to receive						340,000
Collaborative arrangement, additional eligible aggregate payments						1,890,000
Revenues		69,200		$ 40,200		196,600	$ 141,000
Remaining performance obligation		$ 520,100				$ 520,100