Summary of Significant Accounting Policies - Components of Revenue from Contracts with Customers (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenue from contracts with customers:
Total revenue from contracts with customers	$ 61,935	$ 66,090
Revenue recognized under ASC 842	1,760	89
Total revenues	63,695	66,179
Recurring Service Revenues [Member]
Revenue from contracts with customers:
Total revenue from contracts with customers	36,241	39,853
Other Service Revenues [Member]
Revenue from contracts with customers:
Total revenue from contracts with customers	1,509	671
Service [Member]
Revenue from contracts with customers:
Total revenue from contracts with customers	37,750	40,524
Product [Member]
Revenue from contracts with customers:
Total revenue from contracts with customers	24,185	25,566
Total revenues	$ 25,945	$ 25,655