Revenue and Related Matters - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Contract assets	$ 0	$ 0
Contract with customer, contract duration	1 year
Deferred revenue recognized	$ 72,300,000	69,900,000
Revenue expected to be recognized	489,000,000.0
Amortization expense related to deferred commissions	8,800,000	8,100,000
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