Summary of Significant Accounting Policies - Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation of Revenue [Line Items]
Total revenue	$ 60,692	$ 35,904	$ 113,006	$ 65,967
Online
Disaggregation of Revenue [Line Items]
Total revenue	58,146	33,284	108,826	61,808
Wholesale
Disaggregation of Revenue [Line Items]
Total revenue	$ 2,546	$ 2,620	$ 4,180	$ 4,159