Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Detail) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2021 USD ($) Segment	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Accounting Policies [Line Items]
Contract assets	$ 2,507		$ 1,748
Amount billed and collected in advance	34,175	$ 20,760
Revenue recognised out of advance receipt	35,489	$ 20,576
Deferred revenue	$ 2,739		$ 4,053
Number of operating segments \| Segment	1
Accounts Receivable [Member] \| Customer Concentration Risk [Member] \| No Major Customer [Member]
Accounting Policies [Line Items]
Concentration risk percentage	0.00%
Accounts Receivable [Member] \| Customer Concentration Risk [Member] \| Maximum [Member]
Accounting Policies [Line Items]
Concentration risk percentage			14.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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Amount, after allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time, classified as current.

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