Deferred Revenue and Advance Payments (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Deferred Revenue Disclosure [Abstract]
Deferred product licenses revenue, Current	$ 195	$ 1,495
Deferred subscription services revenue, Current	25,689	26,258
Deferred product support revenue, Current	167,282	156,216
Deferred other services revenue, Current	5,814	7,281
Total current deferred revenue and advance payments	198,980	191,250
Deferred product licenses revenue, Non-current	67	139
Deferred subscription services revenue, Non-current	8,317	8,758
Deferred product support revenue, Non-current	5,401	5,055
Deferred other services revenue, Non-current	732	710
Total non-current deferred revenue and advance payments	$ 14,517	$ 14,662