Business Combinations - Summary of Fair Values of Tangible Assets Acquired, Liabilities Assumed, Intangible Assets and Residual Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Feb. 12, 2015	Jun. 02, 2014
Business Acquisition [Line Items]
Goodwill	$ 19,318	$ 19,417
Minimum [Member]
Business Acquisition [Line Items]
Intangible assets, Estimated Useful Life	2 years
Maximum [Member]
Business Acquisition [Line Items]
Intangible assets, Estimated Useful Life	6 years
Developed technology [Member] | Minimum [Member]
Business Acquisition [Line Items]
Intangible assets, Estimated Useful Life	5 years
Developed technology [Member] | Maximum [Member]
Business Acquisition [Line Items]
Intangible assets, Estimated Useful Life	6 years
Customer relationships [Member]
Business Acquisition [Line Items]
Intangible assets, Estimated Useful Life	4 years
Non-compete agreements and tradename [Member] | Minimum [Member]
Business Acquisition [Line Items]
Intangible assets, Estimated Useful Life	2 years
Non-compete agreements and tradename [Member] | Maximum [Member]
Business Acquisition [Line Items]
Intangible assets, Estimated Useful Life	3 years
SocialMoov [Member]
Business Acquisition [Line Items]
Tangible assets acquired	$ 2,741
Liabilities assumed (see Note 8)	(3,382)		$ (1,761)
Goodwill	7,789		$ 7,789
Total purchase price	$ 13,288
Goodwill, Estimated Useful Life	Indefinite
SocialMoov [Member] | Developed technology [Member]
Business Acquisition [Line Items]
Intangible assets, Estimated Fair Value	$ 3,800
Intangible assets, Estimated Useful Life	5 years
SocialMoov [Member] | Customer relationships [Member]
Business Acquisition [Line Items]
Intangible assets, Estimated Fair Value	$ 2,080
Intangible assets, Estimated Useful Life	4 years
SocialMoov [Member] | Tradename [Member]
Business Acquisition [Line Items]
Intangible assets, Estimated Fair Value	$ 260
Intangible assets, Estimated Useful Life	3 years
NowSpots, Inc. [Member]
Business Acquisition [Line Items]
Tangible assets acquired	$ 1,493
Liabilities assumed (see Note 8)	(5,082)			$ (4,713)
Goodwill	11,529			$ 11,529
Total purchase price	$ 16,470
Goodwill, Estimated Useful Life	Indefinite
NowSpots, Inc. [Member] | Developed technology [Member]
Business Acquisition [Line Items]
Intangible assets, Estimated Fair Value	$ 6,110
Intangible assets, Estimated Useful Life	6 years
NowSpots, Inc. [Member] | Customer relationships [Member]
Business Acquisition [Line Items]
Intangible assets, Estimated Fair Value	$ 1,290
Intangible assets, Estimated Useful Life	4 years
NowSpots, Inc. [Member] | Non-compete agreements and tradename [Member]
Business Acquisition [Line Items]
Intangible assets, Estimated Fair Value	$ 1,130
NowSpots, Inc. [Member] | Non-compete agreements and tradename [Member] | Minimum [Member]
Business Acquisition [Line Items]
Intangible assets, Estimated Useful Life	2 years
NowSpots, Inc. [Member] | Non-compete agreements and tradename [Member] | Maximum [Member]
Business Acquisition [Line Items]
Intangible assets, Estimated Useful Life	3 years