Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Revenue	$ 8,667	$ 8,112	$ 22,190	$ 23,381
Cost of revenue	4,220	3,427	10,513	9,749
Gross profit	4,447	4,685	11,677	13,632
Operating expenses
Research and development	1,704	1,156	5,493	3,817
Selling, general and administrative	1,899	1,541	5,092	4,126
Total operating expenses	3,603	2,697	10,585	7,943
Income from operations	844	1,988	1,092	5,689
Other income (expense)	(94)	(59)	130	(69)
Income before income taxes	750	1,929	1,222	5,620
Income taxes	186	646	(16)	1,923
Net income	564	1,283	1,238	3,697
Net income allocable to preferred stockholders		778		2,559
Net income allocable to common stockholders	$ 564	$ 505	$ 1,238	$ 1,138
Net income per share allocable to common stockholders:
Basic	$ 0.03	$ 0.09	$ 0.07	$ 0.25
Diluted	$ 0.03	$ 0.08	$ 0.07	$ 0.24
Weighted average shares outstanding in computing net income per share allocable to common stockholders
Basic	17,045,689	5,827,662	16,936,898	4,515,414
Diluted	17,922,635	6,667,371	18,039,404	5,327,685