Basis of Presentation (Tables)

3 Months Ended

Mar. 31, 2021

Basis of Presentation [Abstract]

Schedule of revenue disaggregated by revenue source

Revenue disaggregated by revenue source for the three months ended March 31, 2021 and 2020 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 March 31,
	2021		2020
Product sales	$	1,163	$	1,050
Royalties		1,816		2,109
Total revenue	$	2,979	$	3,159