Acquisitions - Summary of Deferred Consideration Related to Acquisition (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Deferred consideration, short-term	$ 4,525	$ 5,273
Deferred consideration, short-term	7,564	7,444
Mojoness Inc
Business Acquisition [Line Items]
Deferred consideration, short-term	0	818
Deferred consideration, short-term	0	0
Verio
Business Acquisition [Line Items]
Deferred consideration, short-term	50	50
Deferred consideration, short-term	0	0
Social Booster
Business Acquisition [Line Items]
Deferred consideration, short-term	40	40
Deferred consideration, short-term	25	25
AppMachine
Business Acquisition [Line Items]
Deferred consideration, short-term	4,435	4,365
Deferred consideration, short-term	$ 7,539	$ 7,419