Stock Incentive Plan - Stock-based compensation - Expenses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 62	$ 86	$ 190	$ 282
Cost of Revenue
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		1		1
Engineering and Product Development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		2		14
Sales and Marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		7		39
General and Administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 62	$ 76	$ 190	$ 228