This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

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Amount of increase (decrease) in the value of a contingent consideration liability, including, but not limited to, differences arising upon settlement.

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Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Includes, but is not limited to, one-time termination benefits, termination of an operating lease or other contract, consolidating or closing facilities, and relocating employees, and termination benefits associated with an ongoing benefit arrangement. Excludes expenses associated with special or contractual termination benefits, a discontinued operation or an asset retirement obligation.

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Amount of expenses for special or contractual termination benefits provided to current employees involuntarily terminated under a benefit arrangement associated exit or disposal activities pursuant to an authorized plan. Excludes expenses related to one-time termination benefits, a discontinued operation or an asset retirement obligation.

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Restructuring and Other - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
	Sep. 28, 2014	Dec. 31, 2014	Dec. 31, 2012	Dec. 31, 2013 Employee
Restructuring Cost and Reserve
Severance benefit and charges		$ 400,000us-gaap_SeveranceCosts1
Business acquisition, contingent consideration	(630,000)	(630,000)	(8,761,000)
Acquisition cost related to AIT		400,000
Wireless Test
Restructuring Cost and Reserve
Severance benefit and charges		500,000
Reduction in employees head count		28
System Test and Semiconductor Test
Restructuring Cost and Reserve
Severance benefit and charges		500,000	1,000,000	1,900,000
Reduction in employees head count		8	19	48
System Test
Restructuring Cost and Reserve
Severance benefit and charges		400,000
Reduction in employees head count		4
Corporate And Eliminations
Restructuring Cost and Reserve
Severance benefit and charges		200,000
Reduction in employees head count		3
Change in estimated exit costs related to leased facility				$ (400,000)