Derivative Instruments - Derivative Instruments, Gain (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Oct. 01, 2017	Oct. 02, 2016	Oct. 01, 2017	Oct. 02, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses) reclassified from accumulated other comprehensive income (loss) into current operations	$ 56	$ (241)	$ 21	$ (427)
Designated as Hedging Instrument \| Accumulated Other Comprehensive Income (Loss), Net of Tax
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in shareholders' equity (effective portion)	0	(332)	0	(332)
Designated as Hedging Instrument \| Product Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) reclassified from accumulated other comprehensive income (loss) into current operations (effective portion)	56	(250)	10	(453)
Designated as Hedging Instrument \| Research, Development, and Engineering Expenses
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) reclassified from accumulated other comprehensive income (loss) into current operations (effective portion)	0	1	3	5
Designated as Hedging Instrument \| Selling, General, and Administrative Expenses
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) reclassified from accumulated other comprehensive income (loss) into current operations (effective portion)	0	8	8	21
Not Designated as Hedging Instrument \| Foreign Currency Gain (Loss)
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in current operations	$ 43	$ (24)	$ 139	$ (1,089)

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5618551-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
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-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624171-113959

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The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624171-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4D
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624177-113959

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The effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period.

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Amount after tax of reclassification adjustment from accumulated other comprehensive income of accumulated gain (loss) realized from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's deferred hedging gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=66004124&loc=d3e689-108580

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
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-Section 50
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
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-Section 45
-Paragraph 11
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