Business Combinations - Summary of Fair Values of Tangible Assets Acquired, Liabilities Assumed, Intangible Assets and Residual Goodwill (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	[1]
Business Acquisition [Line Items]
Goodwill	$ 19,578	$ 19,417
Customer relationships [Member]
Business Acquisition [Line Items]
Developed technology, estimated useful life	4 years
SocialMoov [Member]
Business Acquisition [Line Items]
Tangible assets acquired	$ 2,607
Liabilities assumed	(3,508)
Goodwill	8,049
Total purchase price	$ 13,288
Goodwill	Indefinite
SocialMoov [Member] | Developed technology [Member]
Business Acquisition [Line Items]
Developed technology, estimated fair value	$ 3,800
Developed technology, estimated useful life	5 years
SocialMoov [Member] | Customer relationships [Member]
Business Acquisition [Line Items]
Developed technology, estimated fair value	$ 2,080
Developed technology, estimated useful life	4 years
SocialMoov [Member] | Tradename [Member]
Business Acquisition [Line Items]
Developed technology, estimated fair value	$ 260
Developed technology, estimated useful life	3 years

[1] Derived from our audited consolidated financial statements as of December 31, 2015.