Deferred Revenue and Advance Payments (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Deferred Revenue Disclosure [Abstract]
Deferred product licenses revenue, Current	$ 186	$ 481
Deferred subscription services revenue, Current	19,535	16,561
Deferred product support revenue, Current	134,632	161,670
Deferred other services revenue, Current	6,492	8,395
Total current deferred revenue and advance payments	160,845	187,107
Deferred product licenses revenue, Non-current	140	293
Deferred subscription services revenue, Non-current	5,988	97
Deferred product support revenue, Non-current	4,759	3,417
Deferred other services revenue, Non-current	770	537
Total non-current deferred revenue and advance payments	$ 11,657	$ 4,344