Schedule of Segment Reporting Information by Segment Charges and Credit (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jul. 02, 2017	Jul. 03, 2016	Jul. 02, 2017	Jul. 03, 2016
System Test
Segment Reporting Information [Line Items]
Cost of revenues-inventory charge	$ 473	$ 237	$ 1,358	$ 320

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.

No definition available.

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