Revenue from Contracts with Customers - Schedule of Disaggregation of Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation Of Revenue [Line Items]
Total revenue	$ 121,307	$ 106,456	$ 391,382	$ 336,480
Term Licenses [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	55,907	47,386	198,465	160,027
Perpetual Licenses [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	11,696	7,637	32,165	23,557
Maintenance [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	31,296	29,374	91,539	86,467
Professional Software Services [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	3,390	3,413	9,219	8,035
Software Related Services [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	7,650	6,170	23,229	18,548
Client Engineering Services [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	10,060	10,868	31,005	34,386
Other [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	$ 1,308	$ 1,608	$ 5,760	$ 5,460