Basis of Presentation (Tables)

9 Months Ended

Sep. 30, 2019

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, 2019 and 2018 consists of the following (in thousands); revenue excludes sales and usage-based taxes when or if it has been determined that we are acting as a pass-through agent: 

	Three Months Ended September 30,				Nine Months Ended September 30,
	2019		2018		2019		2018
Product sales	$	1,299	$	1,750	$	4,940	$	3,970
Royalties		2,390		2,299		6,346		6,982
Total revenue	$	3,689	$	4,049	$	11,286	$	10,952