Goodwill and Identified Intangible Assets - Summary of Goodwill and Identified Intangible Assets (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 85,234	$ 85,175
Accumulated Amortization	(58,026)	(55,944)
Total future amortization expense	$ 27,208	29,231
Developed Technology
Finite-Lived Intangible Assets [Line Items]
Useful Life	2 years 10 months 12 days
Gross Carrying Amount	$ 31,708	31,707
Accumulated Amortization	(16,512)	(15,216)
Total future amortization expense	$ 15,196	16,491
Customer relationships/contracts [Member]
Finite-Lived Intangible Assets [Line Items]
Useful Life	3 years 10 months 12 days
Gross Carrying Amount	$ 44,433	44,384
Accumulated Amortization	(32,845)	(32,098)
Total future amortization expense	$ 11,588	12,286
Trademarks and Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Useful Life	2 years 10 months 12 days
Gross Carrying Amount	$ 582	573
Accumulated Amortization	(158)	(119)
Total future amortization expense	424	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