Stock-Based Employee Compensation - Summary of share-based compensation expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation, net of amount capitalized	$ 23,220	$ 5,705	$ 998
Capitalized stock-based compensation	472	0	0
Stock-based compensation expense	23,692	5,705	998
Marketplace and Service Cost of Revenue (excluding depreciation & amortization) [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation, net of amount capitalized	329	56	11
Operations and Technology [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation, net of amount capitalized	3,486	864	172
Selling General And Administrative Expenses [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation, net of amount capitalized	$ 19,405	$ 4,785	$ 815