Deferred Revenue and Advance Payments (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Deferred Revenue Disclosure [Abstract]
Deferred product licenses revenue, Current	$ 555	$ 1,768
Deferred subscription services revenue, Current	15,641	13,508
Deferred product support revenue, Current	166,306	152,501
Deferred other services revenue, Current	7,568	8,763
Total current deferred revenue and advance payments	190,070	176,540
Deferred product licenses revenue, Non-current	479	542
Deferred subscription services revenue, Non-current	247	2,384
Deferred product support revenue, Non-current	3,231	3,091
Deferred other services revenue, Non-current	582	452
Total non-current deferred revenue and advance payments	$ 4,539	$ 6,469