Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenue:
Total Revenue	$ 3,689	$ 4,049	$ 11,286	$ 10,952
Cost of revenue:
Total Cost of revenue	513	743	2,489	1,891
Gross profit	3,176	3,306	8,797	9,061
Operating expenses:
Selling, general and administrative	1,560	1,592	4,907	5,118
Research and development	691	863	2,008	2,598
Restructuring charges	0	0	2	0
Total Operating expenses	2,251	2,455	6,917	7,716
Income from operations	925	851	1,880	1,345
Income from operations before income taxes	925	851	1,880	1,345
Income tax benefit	(5,205)	0	(5,205)	0
Net income	$ 6,130	$ 851	$ 7,085	$ 1,345
Net income per share:
Basic (in dollars per share)	$ 1.17	$ 0.16	$ 1.35	$ 0.26
Diluted (in dollars per share)	$ 1.16	$ 0.16	$ 1.35	$ 0.26
Weighted average number of common shares outstanding:
Basic (in shares)	5,252	5,212	5,240	5,200
Diluted (in shares)	5,270	5,244	5,259	5,206
Product sales [Member]
Revenue:
Total Revenue	$ 1,299	$ 1,750	$ 4,940	$ 3,970
Cost of revenue:
Total Cost of revenue	421	652	2,214	1,616
Royalties [Member]
Revenue:
Total Revenue	2,390	2,299	6,346	6,982
Cost of revenue:
Total Cost of revenue	$ 92	$ 91	$ 275	$ 275