Summary of Significant Accounting Policies - Components of Revenue from Contracts with Customers (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenue from contracts with customers:
Total revenue from contracts with customers	$ 65,353	$ 56,030	$ 127,288	$ 122,003
Revenue recognized under ASC 842	575	702	2,335	908
Total revenues	65,928	56,732	129,623	122,911
Recurring Service Revenues [Member]
Revenue from contracts with customers:
Total revenue from contracts with customers	36,355	37,006	72,596	76,859
Other Service Revenues [Member]
Revenue from contracts with customers:
Total revenue from contracts with customers	1,187	1,423	2,696	2,094
Service [Member]
Revenue from contracts with customers:
Total revenue from contracts with customers	37,542	38,429	75,292	78,953
Product [Member]
Revenue from contracts with customers:
Total revenue from contracts with customers	27,811	17,601	51,996	43,050
Total revenues	$ 28,386	$ 18,303	$ 54,331	$ 43,958