Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Net revenues	$ 2,160	$ 3,130	$ 5,242	$ 7,983
Platform subscriptions and services revenue
Disaggregation of Revenue [Line Items]
Net revenues	1,771	2,860	4,472	7,274
Application transaction revenue
Disaggregation of Revenue [Line Items]
Net revenues	$ 389	$ 270	$ 770	$ 709