Basis of Presentation (Tables)

9 Months Ended

Sep. 30, 2018

Basis of Presentation [Abstract]

Schedule of revenue disaggregated by revenue source

Revenue disaggregated by revenue source for the three and nine months ended September 30, 2018 and 2017 consists of the following (in thousands). Revenue excludes sales and usage-based taxes where it has been determined that we are acting as a pass-through agent. 

	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Product sales	$	1,750	$	1,120	$	3,970	$	4,189
Royalties		2,299		2,504		6,982		5,994
Total revenue	$	4,049	$	3,624	$	10,952	$	10,183