Stockholders' Equity and Stock-Based Compensation - Allocated Share-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 26,151	$ 3,063	$ 2,114
Cost of subscription, transaction, and services
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	1,710	263	133
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	4,749	697	384
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	4,048	465	296
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 15,644	$ 1,638	$ 1,301