Condensed Consolidated Statements of Income and Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Statement [Abstract]
Revenue	$ 11,966	$ 14,013	$ 24,999	$ 27,600
Cost of goods sold	4,302	5,022	8,870	10,147
Gross profit	7,664	8,991	16,129	17,453
Operating expenses:
Sales and marketing	2,681	2,753	5,306	5,375
Research and product development	2,096	2,054	4,365	3,996
General and administrative	1,567	1,891	3,165	3,890
Total operating expenses	6,344	6,698	12,836	13,261
Operating income	1,320	2,293	3,293	4,192
Other income, net	84	85	94	190
Income before income taxes	1,404	2,378	3,387	4,382
Provision for income taxes	449	863	1,064	1,595
Net income	$ 955	$ 1,515	$ 2,323	$ 2,787
Basic earnings per common share	$ 0.1	$ 0.17	$ 0.25	$ 0.31
Diluted earnings per common share	$ 0.1	$ 0.16	$ 0.24	$ 0.29
Basic weighted average shares outstanding	9,112,613	9,119,907	9,154,568	9,110,062
Diluted weighted average shares outstanding	9,362,037	9,603,682	9,512,559	9,560,914
Comprehensive income:
Net income	$ 955	$ 1,515	$ 2,323	$ 2,787
Other comprehensive income:
Change in unrealized gains (losses) on available-for-sale securities, net of tax	97	(77)	218	(23)
Change in foreign currency translation adjustment	(20)	129	13	(50)
Comprehensive income	$ 1,032	$ 1,567	$ 2,554	$ 2,714