Stock-based Compensation - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 2,098	$ 3,850
Cost of revenue, exclusive of depreciation and amortization
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	0	0
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	49	120
Customer service
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	26	29
Technical operations and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	222	320
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 1,801	$ 3,381