Revenue Recognition - Product Revenue Allowance and Accrual Activity (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Mar. 31, 2018	Jun. 30, 2018
Contractual Adjustments
Balance at Beginning of Period	$ 62,164	$ 62,164
Provisions related to current period sales	85,308	114,408
Adjustments related to prior period sales	836	(2,870)
Payments/returns relating to current period sales	(44,633)	(87,985)
Payments/returns relating to prior period sales	(39,441)	(16,532)
Balance at End of Period	64,234	71,255
Governmental Rebates
Balance at Beginning of Period	50,598	50,598
Provisions related to current period sales	31,028	40,486
Adjustments related to prior period sales	5,350	(513)
Payments/returns relating to current period sales	0	(2,453)
Payments/returns relating to prior period sales	(25,149)	(25,993)
Balance at End of Period	61,827	73,354
Revenue, Allowance [Roll Forward]
Balance at Beginning of Period	112,762	112,762
Provisions related to current period sales	116,336	154,894
Adjustments related to prior period sales	6,186	(3,383)
Payments/returns relating to current period sales	(44,633)	(90,438)
Payments/returns relating to prior period sales	(64,590)	(42,525)
Balance at End of Period	$ 126,061	$ 144,609