Goodwill and Identified Intangible Assets - Summary of Goodwill and Identified Intangible Assets (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 27, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 85,359	$ 85,592
Accumulated Amortization	(78,841)	(72,775)
Total future amortization expense	$ 6,518	12,817
Developed Core Technology
Finite-Lived Intangible Assets [Line Items]
Useful Life	4 months 24 days
Gross Carrying Amount	$ 31,707	31,707
Accumulated Amortization	(29,461)	(25,576)
Total future amortization expense	$ 2,246	6,131
Customer relationships/contracts
Finite-Lived Intangible Assets [Line Items]
Useful Life	1 year 4 months 24 days
Gross Carrying Amount	$ 44,501	44,650
Accumulated Amortization	(40,291)	(38,146)
Total future amortization expense	$ 4,210	6,504
Trademarks and Trade Names
Finite-Lived Intangible Assets [Line Items]
Useful Life	4 months 24 days
Gross Carrying Amount	$ 595	623
Accumulated Amortization	(533)	(441)
Total future amortization expense	62	182
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	3,056	3,112
Accumulated Amortization	(3,056)	(3,112)
Total future amortization expense	$ 0	$ 0