Segment Reporting Financial Information of Segments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenue
External customers									$ 476,016	$ 369,658	$ 276,428
Income (loss) from operations	6,299	9,533	(2,561)	(7,205)	15,293	6,736	(1,404)	(3,444)	6,066	17,181	13,093
Goodwill	159,342				159,342				159,342	159,342	129,428
Total assets	563,316				461,665				563,316	461,665
Consumer
Revenue
External customers									449,193	340,121	254,678
Intersegment revenue									0	0	0
Income (loss) from operations									20,160	27,086	18,840
Goodwill	99,805				99,805				99,805	99,805
Total assets	455,035				348,000				455,035	348,000
Enterprise
Revenue
External customers									26,823	29,537	21,750
Intersegment revenue									6,710	5,316	3,506
Income (loss) from operations									(14,094)	(9,905)	(5,747)
Goodwill	59,537				59,537				59,537	59,537
Total assets	108,905				114,146				108,905	114,146
Eliminations
Revenue
Intersegment revenue									(6,710)	(5,316)	(3,506)
Total assets	$ (624)				$ (481)				$ (624)	$ (481)