Revenue Recognition - Product Revenue Allowance and Accrual Activity (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($)
Contractual Adjustments
Balance at December 31, 2017	$ 62,164
Provisions related to current period sales	85,308
Adjustments related to prior period sales	836
Payments/returns relating to current period sales	(44,633)
Payments/returns relating to prior period sales	(39,441)
Balance at March 31, 2018	64,234
Governmental Rebates
Balance at December 31, 2017	50,598
Provisions related to current period sales	31,028
Adjustments related to prior period sales	5,350
Payments/returns relating to current period sales	0
Payments/returns relating to prior period sales	(25,149)
Balance at March 31, 2018	61,827
Revenue, Allowance [Roll Forward]
Balance at December 31, 2017	112,762
Provisions related to current period sales	116,336
Adjustments related to prior period sales	6,186
Payments/returns relating to current period sales	(44,633)
Payments/returns relating to prior period sales	(64,590)
Balance at March 31, 2018	$ 126,061