Revenue and Related Matters - Summary of Allowance for Expected Credit Losses on Accounts Receivable (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($)
Receivables [Abstract]
Balance at December 31, 2020	$ 708
Provision for expected credit losses	86
Write-offs	(63)
Balance at March 31, 2021	$ 731