Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenue:
Total Revenue	$ 3,750	$ 3,689	$ 10,296	$ 11,286
Cost of revenue:
Total Cost of revenue	883	513	2,117	2,489
Gross profit	2,867	3,176	8,179	8,797
Operating expenses:
Selling, general and administrative	1,422	1,560	4,894	4,907
Research and development	804	691	2,548	2,008
Restructuring charges	0	0	0	2
Total Operating expenses	2,226	2,251	7,442	6,917
Income from operations before income taxes	641	925	737	1,880
Income tax expense (benefit)	(18)	(5,205)	39	(5,205)
Net income	$ 659	$ 6,130	$ 698	$ 7,085
Net income per share:
Basic (in dollars per share)	$ 0.12	$ 1.17	$ 0.13	$ 1.35
Diluted (in dollars per share)	$ 0.12	$ 1.16	$ 0.13	$ 1.35
Weighted average number of common shares outstanding:
Basic (in shares)	5,306	5,252	5,290	5,240
Diluted (in shares)	5,311	5,270	5,306	5,259
Product sales [Member]
Revenue:
Total Revenue	$ 1,538	$ 1,299	$ 3,760	$ 4,940
Cost of revenue:
Total Cost of revenue	791	421	1,842	2,214
Royalties [Member]
Revenue:
Total Revenue	2,212	2,390	6,536	6,346
Cost of revenue:
Total Cost of revenue	$ 92	$ 92	$ 275	$ 275