Share-based Compensation - Summary of stock based compensation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$ 769	$ 97	$ 2,833	$ 322
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	295	$ 97	1,811	$ 322
Commission and other agent-related cost
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$ 474		$ 1,022