Goodwill and Identified Intangible Assets - Summary of Goodwill and Identified Intangible Assets (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 28, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 85,698	$ 85,857
Accumulated Amortization	(70,760)	(64,578)
Total future amortization expense	$ 14,938	21,279
Developed Core Technology
Finite-Lived Intangible Assets [Line Items]
Useful Life	1 year 4 months 24 days
Gross Carrying Amount	$ 31,707	31,707
Accumulated Amortization	(24,281)	(20,396)
Total future amortization expense	$ 7,426	11,311
Customer relationships/contracts
Finite-Lived Intangible Assets [Line Items]
Useful Life	2 years 4 months 24 days
Gross Carrying Amount	$ 44,718	44,819
Accumulated Amortization	(37,431)	(35,205)
Total future amortization expense	$ 7,287	9,614
Trademarks and Trade Names
Finite-Lived Intangible Assets [Line Items]
Useful Life	1 year 4 months 24 days
Gross Carrying Amount	$ 635	654
Accumulated Amortization	(410)	(300)
Total future amortization expense	225	354
Maintenance Agreements and Related Relationships
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
Order Backlog
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	3,138	3,177
Accumulated Amortization	(3,138)	(3,177)
Total future amortization expense	$ 0	$ 0