The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Goodwill, Other Intangible Assets and Other Assets - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2015	Jun. 28, 2014	Jun. 27, 2015	Jun. 28, 2014	Dec. 27, 2014
Business Acquisition [Line Items]
Goodwill	$ 48,751		$ 48,751		$ 48,751
Amortization of Acquired Intangible Assets	900	$ 900	$ 1,800	$ 1,800
Minimum
Business Acquisition [Line Items]
Estimated useful life of intangible assets			3 years
Maximum
Business Acquisition [Line Items]
Estimated useful life of intangible assets			10 years
Home Robots \| Evolution Robotics, Inc. (ER)
Business Acquisition [Line Items]
Goodwill	41,100		$ 41,100
Defense & Security \| Nekton Research LLC [Member]
Business Acquisition [Line Items]
Goodwill	$ 7,700		$ 7,700