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Goodwill and Acquired Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Jul. 03, 2016	Oct. 01, 2017	Oct. 02, 2016	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Line Items]
Goodwill impairment					$ 254,946
Goodwill	$ 249,277			$ 249,277		$ 223,343
Intangible assets impairment					83,339
Acquired intangible assets amortization	7,028	$ 8,487		23,145	44,725
Wireless Test
Goodwill and Intangible Assets Disclosure [Line Items]
Employee reduction, percentage			11.00%
Goodwill impairment			$ 254,946		254,946
Goodwill	$ 7,976		8,000	$ 7,976		$ 7,976
Intangible assets impairment			$ 83,300		$ 83,339
Wireless Test | Sales Revenue, Segment | Customer Concentration Risk | Minimum
Goodwill and Intangible Assets Disclosure [Line Items]
Concentration risk, percentage			51.00%
Wireless Test | Sales Revenue, Segment | Customer Concentration Risk | Maximum
Goodwill and Intangible Assets Disclosure [Line Items]
Concentration risk, percentage			73.00%

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Goodwill and Intangible Assets Disclosure [Line Items]

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Reduction in Employees, Percentage

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For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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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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