Goodwill and Identified Intangible Assets - Summary of Goodwill and Identified Intangible Assets (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 85,483	$ 85,175
Accumulated Amortization	(60,166)	(55,944)
Total future amortization expense	$ 25,317	29,231
Developed Technology
Finite-Lived Intangible Assets [Line Items]
Useful Life	2 years 8 months 4 days
Gross Carrying Amount	$ 31,708	31,707
Accumulated Amortization	(17,807)	(15,216)
Total future amortization expense	$ 13,901	16,491
Customer relationships/contracts [Member]
Finite-Lived Intangible Assets [Line Items]
Useful Life	3 years 8 months 4 days
Gross Carrying Amount	$ 44,643	44,384
Accumulated Amortization	(33,641)	(32,098)
Total future amortization expense	$ 11,002	12,286
Trademarks and Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Useful Life	2 years 8 months 4 days
Gross Carrying Amount	$ 621	573
Accumulated Amortization	(207)	(119)
Total future amortization expense	414	454
Maintenance agreements and related relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	5,500	5,500
Accumulated Amortization	(5,500)	(5,500)
Total future amortization expense	0	0
Backlog
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	3,011	3,011
Accumulated Amortization	(3,011)	(3,011)
Total future amortization expense	$ 0	$ 0