Revenue and Related Matters - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Contract assets	$ 0	$ 0	$ 0	$ 0
Contract with customer, contract duration			1 year
Deferred revenue recognized	43,600,000	43,200,000	$ 115,900,000	113,100,000
Revenue expected to be recognized	372,000,000.0		372,000,000.0
Amortization expense related to deferred commissions	$ 10,000,000.0	$ 9,000,000.0	18,900,000	17,200,000
Impairment of deferred commissions			$ 0	$ 0
Maximum [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Contract with customer, expected payment term			one year