Summary of Significant Accounting Policies - Revenue Recognition - Condensed Statement of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Summary of Significant Accounting Policies
Total revenue	$ 14,853
Total cost of sales	4,898
Gross profit	9,955	$ 4,217
Loss from operations	(1,110)	(5,875)
Net loss and comprehensive loss	$ (1,277)	$ (6,086)
Net loss per common share, basic and diluted	$ (0.09)	$ (0.49)
Product sales
Summary of Significant Accounting Policies
Total revenue	$ 9,365
Licensing, royalty and other revenue
Summary of Significant Accounting Policies
Total revenue	5,488
ASU 2014-09 | Balances without the adoption of Topic 606
Summary of Significant Accounting Policies
Total revenue	14,051
Total cost of sales	4,604
Gross profit	9,447
Loss from operations	(1,618)
Net loss and comprehensive loss	$ (1,785)
Net loss per common share, basic and diluted	$ (0.12)
ASU 2014-09 | Adjustments
Summary of Significant Accounting Policies
Total revenue	$ (802)
Total cost of sales	(294)
Gross profit	(508)
Loss from operations	(508)
Net loss and comprehensive loss	$ (508)
Net loss per common share, basic and diluted	$ (0.03)
ASU 2014-09 | Product sales | Balances without the adoption of Topic 606
Summary of Significant Accounting Policies
Total revenue	$ 8,534
ASU 2014-09 | Product sales | Adjustments
Summary of Significant Accounting Policies
Total revenue	(831)
ASU 2014-09 | Licensing, royalty and other revenue | Balances without the adoption of Topic 606
Summary of Significant Accounting Policies
Total revenue	5,517
ASU 2014-09 | Licensing, royalty and other revenue | Adjustments
Summary of Significant Accounting Policies
Total revenue	$ 29