Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Revenue:
Total Revenue	$ 2,819	$ 3,788	$ 5,571	$ 6,767
Cost of revenue:
Total Cost of revenue	824	827	1,440	1,533
Gross profit	1,995	2,961	4,131	5,234
Operating expenses:
Selling, general and administrative	1,324	1,516	3,009	2,882
Research and development	526	541	954	1,037
Total Operating expenses	1,850	2,057	3,963	3,919
Income from operations	145	904	168	1,315
Other income	10	0	21	925
Investment income	(30)	0	(25)	0
Interest expense	(18)	0	(36)	0
Income from operations before income taxes	107	904	128	2,240
Income tax expense	33	152	36	357
Net income	$ 74	$ 752	$ 92	$ 1,883
Net income per share:
Basic (in dollars per share)	$ 0.01	$ 0.14	$ 0.02	$ 0.35
Diluted (in dollars per share)	$ 0.01	$ 0.14	$ 0.02	$ 0.35
Weighted average number of common shares outstanding:
Basic (in shares)	5,381	5,341	5,371	5,332
Diluted (in shares)	5,387	5,350	5,373	5,343
Product sales [Member]
Revenue:
Total Revenue	$ 1,432	$ 1,305	$ 2,366	$ 2,468
Cost of revenue:
Total Cost of revenue	719	730	1,230	1,343
Royalties [Member]
Revenue:
Total Revenue	1,387	2,483	3,205	4,299
Cost of revenue:
Total Cost of revenue	$ 105	$ 97	$ 210	$ 190