Segment Reporting - Financial Information of Segments (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenue
External customers									$ 587,469	$ 476,016	$ 369,658
Loss from operations	$ 16,864	$ (87,350)	$ 865	$ (15,132)	$ 6,299	$ 9,533	$ (2,561)	$ (7,205)	(84,753)	6,066	17,181
Goodwill	172,087				159,342				172,087	159,342	159,342
Total assets	592,809				563,316				592,809	563,316
Consumer
Revenue
External customers									559,467	449,193	340,121
Intersegment revenue									0	0	0
Loss from operations									(70,109)	20,160	27,086
Goodwill	112,550				99,805				112,550	99,805
Total assets	492,796				455,035				492,796	455,035
Enterprise
Revenue
External customers									28,002	26,823	29,537
Intersegment revenue									8,405	6,710	5,316
Loss from operations									(14,644)	(14,094)	(9,905)
Goodwill	59,537				59,537				59,537	59,537
Total assets	100,753				108,905				100,753	108,905
Eliminations
Revenue
Intersegment revenue									(8,405)	(6,710)	$ (5,316)
Total assets	$ (740)				$ (624)				$ (740)	$ (624)