Significant Accounting Policies - Sales Allowances and Accruals (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash Discounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance beginning of period	$ 887	$ 4,142	$ 2,662
Allowances for sales, current period	1,854	9,212	18,299
Actual credits issued for prior year’s sales	(887)	(3,927)	(2,411)
Actual credits issued for sales, current period	(1,573)	(8,540)	(14,408)
Balance end of period	281	887	4,142
Returns [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance beginning of period	8,743	3,349	2,433
Allowances for sales, current period	(1,424)	12,143	5,836
Actual credits issued for prior year’s sales	(5,233)	(3,528)	(1,724)
Actual credits issued for sales, current period	(502)	(3,221)	(3,196)
Balance end of period	1,584	8,743	3,349
Chargebacks [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance beginning of period	15,716	44,399	25,040
Allowances for sales, current period	36,197	107,564	175,001
Actual credits issued for prior year’s sales	(15,610)	(40,419)	(25,888)
Actual credits issued for sales, current period	(34,408)	(95,828)	(129,754)
Balance end of period	1,895	15,716	44,399
Rebates [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance beginning of period	100	0	0
Allowances for sales, current period	(6)	833	0
Actual credits issued for prior year’s sales	(50)		0
Actual credits issued for sales, current period	(29)	(733)	0
Balance end of period	15	100	0
Fees-for-Service [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance beginning of period	2,680	924	3,127
Allowances for sales, current period	3,166	14,249	12,453
Actual credits issued for prior year’s sales	(2,655)	(1,179)	(3,246)
Actual credits issued for sales, current period	(2,365)	(11,314)	(11,410)
Balance end of period	$ 826	$ 2,680	$ 924