Summary of Significant Accounting Policies - Summary of Disaggregation of Revenue (Detail) - 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]
Total revenues	$ 67,367	$ 52,254	$ 203,652	$ 145,407
Subscription fees
Disaggregation of Revenue [Line Items]
Total revenues	58,988	46,808	179,732	129,579
Professional services
Disaggregation of Revenue [Line Items]
Total revenues	5,706	3,987	16,812	11,387
Other
Disaggregation of Revenue [Line Items]
Total revenues	$ 2,673	$ 1,459	$ 7,108	$ 4,441