Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenue:
Total Revenue	$ 3,788	$ 3,387	$ 6,767	$ 6,546
Cost of revenue:
Total Cost of revenue	827	611	1,533	1,234
Gross profit	2,961	2,776	5,234	5,312
Operating expenses:
Selling, general and administrative	1,516	1,563	2,882	3,472
Research and development	541	842	1,037	1,744
Total Operating expenses	2,057	2,405	3,919	5,216
Income from operations	904	371	1,315	96
Other income, net	0	0	925	0
Income from operations before income taxes	904	371	2,240	96
Income tax expense	152	221	357	57
Net income	$ 752	$ 150	$ 1,883	$ 39
Net income (loss) per share:
Basic (in dollars per share)	$ 0.14	$ 0.03	$ 0.35	$ 0.01
Diluted (in dollars per share)	$ 0.14	$ 0.03	$ 0.35	$ 0.01
Weighted average number of common shares outstanding:
Basic (in shares)	5,341	5,296	5,332	5,281
Diluted (in shares)	5,350	5,299	5,343	5,299
Product sales [Member]
Revenue:
Total Revenue	$ 1,305	$ 1,172	$ 2,468	$ 2,222
Cost of revenue:
Total Cost of revenue	730	520	1,343	1,051
Royalties [Member]
Revenue:
Total Revenue	2,483	2,215	4,299	4,324
Cost of revenue:
Total Cost of revenue	$ 97	$ 91	$ 190	$ 183