Revenue from Contracts with Customers - Schedule of Disaggregation of Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation Of Revenue [Line Items]
Total revenue	$ 106,456	$ 100,406	$ 336,480	$ 335,038
Term Licenses [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	47,386	38,794	160,027	149,825
Perpetual Licenses [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	7,637	8,059	23,557	30,302
Maintenance [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	29,374	26,898	86,467	74,983
Professional Services and Other [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	3,413	4,065	8,035	10,405
Software [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	$ 87,810	$ 77,816	$ 278,086	$ 265,515