Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Total revenue	$ 37,503	$ 49,417
Cost of sales	19,172	24,083
Gross profit	18,331	25,334
Operating expenses:
Research and development	14,183	23,637
General and administrative	12,414	12,551
Sales and marketing	5,364	6,467
Restructuring	782
Total operating expenses	32,743	42,655
Loss from operations	(14,412)	(17,321)
Interest expense	(747)	(890)
Other income, net	490	457
Net loss and comprehensive loss	$ (14,669)	$ (17,754)
Net loss per common share, basic and diluted	$ (0.85)	$ (1.08)
Weighted-average shares used to compute net loss per common share, basic and diluted	17,317,042	16,372,638
Operating expenses includes stock-based compensation as follows:
Total stock-based compensation	$ 3,554	$ 2,668
Research and development
Operating expenses includes stock-based compensation as follows:
Total stock-based compensation	736	492
General and administrative
Operating expenses includes stock-based compensation as follows:
Total stock-based compensation	2,460	1,811
Sales and marketing
Operating expenses includes stock-based compensation as follows:
Total stock-based compensation	358	365
Product sales
Total revenue	34,595	39,514
Licensing, royalty and other revenue
Total revenue	$ 2,908	$ 9,903