Unaudited Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenue	$ 2,369	$ 1,543	$ 4,632	$ 3,102
Cost of revenue	926	632	1,778	1,215
Gross profit	1,443	911	2,854	1,887
Operating expenses:
Sales and marketing	431	415	845	776
Research and development	200	594	503	1,179
General and administrative	290	282	585	613
Operating income (loss)	522	(380)	921	(681)
Interest expense, net	(48)	(58)	(101)	(108)
Net income (loss)	474	(438)	820	(789)
Preferred stock dividends accrued	(35)	(35)	(69)	(69)
Net income (loss) attributable to common stockholders	$ 439	$ (473)	$ 751	$ (858)
Net income (loss) per share attributable to common stockholders:
Basic (in dollars per share)	$ 0.03	$ (0.04)	$ 0.06	$ (0.07)
Diluted (in dollars per share)	$ 0.03	$ (0.04)	$ 0.05	$ (0.07)
Weighted average common shares outstanding:
Basic (in shares)	13,017	12,798	12,982	12,772
Diluted (in shares)	14,791	12,798	14,756	12,772