Segment Information - Information About Segments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Apr. 05, 2015	Mar. 30, 2014
Segment Reporting Information [Line Items]
Product revenue	$ 105,775us-gaap_SalesRevenueGoodsNet	$ 83,569us-gaap_SalesRevenueGoodsNet
Service revenue	7,659us-gaap_SalesRevenueServicesNet	7,360us-gaap_SalesRevenueServicesNet
Operating income	23,917us-gaap_OperatingIncomeLoss	22,443us-gaap_OperatingIncomeLoss
Operating Segments \| MVSD
Segment Reporting Information [Line Items]
Product revenue	97,494	77,618
Service revenue	3,879	3,698
Operating income	33,307	28,292
Operating Segments \| SISD
Segment Reporting Information [Line Items]
Product revenue	8,281	5,951
Service revenue	3,780	3,662
Operating income	1,896	1,013
Reconciling Items
Segment Reporting Information [Line Items]
Operating income	$ (11,286)	$ (6,862)

The net result for the period of deducting operating expenses from operating revenues.

No definition available.

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- Definition

Aggregate revenue during the period from the sale of goods in the normal course of business, after deducting returns, allowances and discounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1(a))

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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- Definition

Aggregate revenue during the period from services rendered in the normal course of business, after deducting allowances and discounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1(d))

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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