Statements of Operations and Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Total revenue	$ 14,795	$ 10,120	$ 36,923	$ 32,054
Cost of sales	6,347	7,791	15,294	19,183
Gross profit	8,448	2,329	21,629	12,871
Operating expenses:
Research and development	3,105	2,579	8,901	8,383
General and administrative	2,996	2,549	8,177	7,797
Sales and marketing	1,272	912	3,304	3,071
Total operating expenses	7,373	6,040	20,382	19,251
Income (loss) from operations	1,075	(3,711)	1,247	(6,380)
Interest expense	(165)	(157)	(461)	(501)
Other (expense) income, net	(8)	(3)	(35)	60
Net income (loss) before income taxes	902	(3,871)	751	(6,821)
Income tax expense	(22)	(24)	(75)	(100)
Net income (loss) and comprehensive income (loss)	$ 880	$ (3,895)	$ 676	$ (6,921)
Net income (loss) per share attributable to common share, basic	$ 0.05	$ (0.21)	$ 0.03	$ (0.37)
Net income (loss) per share attributable to common stockholders, diluted	$ 0.04	$ (0.21)	$ 0.03	$ (0.37)
Weighted average common shares used to compute net income (loss) per common share attributable to common stockholders, basic	19,511,132	18,942,163	19,296,241	18,705,149
Weighted average common shares used to compute net income (loss) per common share attributable to common stockholders, diluted	19,912,918	18,942,163	19,787,889	18,705,149
Product sales
Total revenue	$ 12,037	$ 9,577	$ 31,292	$ 30,139
Cost of sales	6,043	7,763	14,629	19,009
Licensing, royalty and other revenue
Total revenue	2,758	543	5,631	1,915
Cost of sales	$ 304	$ 28	$ 665	$ 174