Composition of Total Revenue - Schedule of Net Product Sales by Geography (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Total revenues	$ 29,402	$ 25,268	$ 24,168	$ 30,495	$ 28,570	$ 36,395	$ 34,301	$ 29,101	$ 109,333	$ 128,367	$ 146,444
Product [Member]
Segment Reporting Information [Line Items]
Total revenues									104,466	116,178	128,596
United States [Member] | Product [Member]
Segment Reporting Information [Line Items]
Total revenues									91,822	107,135	125,074
Total International [Member] | Product [Member]
Segment Reporting Information [Line Items]
Total revenues									12,644	9,043	3,522
Total International [Member] | Europe [Member] | Product [Member]
Segment Reporting Information [Line Items]
Total revenues									11,220	7,727	3,522
Total International [Member] | Asia Pacific [Member] | Product [Member]
Segment Reporting Information [Line Items]
Total revenues									$ 1,424	$ 1,316	$ 0
Geographic Concentration Risk [Member] | Sales [Member]
Segment Reporting Information [Line Items]
Percentage of sales									100.00%	100.00%	100.00%
Geographic Concentration Risk [Member] | Sales [Member] | United States [Member]
Segment Reporting Information [Line Items]
Percentage of sales									87.90%	92.20%	97.30%
Geographic Concentration Risk [Member] | Sales [Member] | Total International [Member]
Segment Reporting Information [Line Items]
Percentage of sales									12.10%	7.80%	2.70%
Geographic Concentration Risk [Member] | Sales [Member] | Total International [Member] | Europe [Member]
Segment Reporting Information [Line Items]
Percentage of sales									10.70%	6.70%	2.70%
Geographic Concentration Risk [Member] | Sales [Member] | Total International [Member] | Asia Pacific [Member]
Segment Reporting Information [Line Items]
Percentage of sales									1.40%	1.10%	0.00%