General - Condensed Consolidated Balance Sheet (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
ASSETS
Deferred costs	$ 31,318	$ 29,966
Deferred costs, non-current	10,239	9,967
Deferred income tax asset		13,697
LIABILITIES
Accrued compensation	11,617	15,228
Deferred revenue	21,583	17,863
Deferred revenue, non-current	2,691	2,731
STOCKHOLDERS’ EQUITY
Accumulated deficit	$ (5,357)	(8,611)
ASU 2014-09 [Member] | As Previously Reported [Member]
ASSETS
Deferred costs		25,091
Deferred costs, non-current		6,770
Deferred income tax asset		17,551
LIABILITIES
Accrued compensation		15,886
Deferred revenue		16,407
Deferred revenue, non-current		10,602
STOCKHOLDERS’ EQUITY
Accumulated deficit		(19,902)
ASU 2014-09 [Member] | Adjustments [Member]
ASSETS
Deferred costs		4,875
Deferred costs, non-current		3,197
Deferred income tax asset		(3,854)
LIABILITIES
Accrued compensation		(658)
Deferred revenue		1,456
Deferred revenue, non-current		(7,871)
STOCKHOLDERS’ EQUITY
Accumulated deficit		$ 11,291