Revenue, Gross Profit and Gross Profit Margin by Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Oct. 02, 2015	Sep. 26, 2014	Oct. 02, 2015	Sep. 26, 2014
Segment Reporting Information [Line Items]
Revenue	$ 92,271	$ 94,656	$ 283,379	$ 270,694
Gross Profit	$ 39,910	$ 39,683	$ 121,261	$ 110,439
Gross profit margin percentage	43.30%	41.90%	42.80%	40.80%
Laser Products
Segment Reporting Information [Line Items]
Revenue	$ 41,330	$ 45,806	$ 128,475	$ 131,494
Gross Profit	$ 18,851	$ 20,269	$ 57,176	$ 54,437
Gross profit margin percentage	45.60%	44.20%	44.50%	41.40%
Vision Technologies
Segment Reporting Information [Line Items]
Revenue	$ 30,992	$ 32,680	$ 93,319	$ 89,838
Gross Profit	$ 12,152	$ 12,945	$ 36,823	$ 35,672
Gross profit margin percentage	39.20%	39.60%	39.50%	39.70%
Precision Motion
Segment Reporting Information [Line Items]
Revenue	$ 19,949	$ 16,170	$ 61,585	$ 49,362
Gross Profit	$ 9,233	$ 6,776	$ 28,309	$ 21,141
Gross profit margin percentage	46.30%	41.90%	46.00%	42.80%
Unallocated Corporate and Shared Services
Segment Reporting Information [Line Items]
Gross Profit	$ (326)	$ (307)	$ (1,047)	$ (811)

Percentage of aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity over amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process.

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Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1,2)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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+ References

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