Stock Option Plan - Stock-based compensation (Details 2) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 66	$ 31	$ 135	$ 63
Cost of Revenue
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	1	1	1	1
Engineering and Product Development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	5	5	18	7
Sales and Marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	17	10	42	25
General and Administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 43	$ 15	$ 74	$ 30