Collaboration Agreements (Teva Agreement) (Details) - USD ($) $ in Thousands		1 Months Ended	3 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2016	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Collaboration Agreements [Line Items]
Accounts and Notes Receivable, Net			$ 242,014		$ 242,014	$ 175,263
Deferred revenue, current portion			320,138		320,138	231,664
Teva Pharmaceuticals [Member] | Collaborative Arrangement [Member]
Collaboration Agreements [Line Items]
Deferred Revenue, Additions	$ 250,000	$ 250,000
Collaboration revenue					221,500	37,900
Revenue Recognition, Milestone Method, Revenue Recognized			$ 35,000	$ 25,000
Collaborative Arrangement, Additional Eligible Aggregate Payments						$ 1,890,000
Teva Pharmaceuticals [Member]
Collaboration Agreements [Line Items]
Aggregate future development milestone payments the Company is eligible to receive					$ 400,000