Revenue and Related Matters - Summary of Allowance for Expected Credit Losses on Accounts Receivable (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2021 USD ($)
Receivables [Abstract]
Balance at December 31, 2020	$ 708
Provision for expected credit losses	211
Write-offs	(127)
Balance at June 30, 2021	$ 792