Sales and Gross Margin for Reportable Segments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 28, 2012		Sep. 30, 2011		Sep. 28, 2012		Sep. 30, 2011
Segment Reporting Information [Line Items]
Sales	$ 69,520		$ 78,704		$ 205,085		$ 238,816
Gross profit	28,853		34,585		87,201		105,327
Laser Products
Segment Reporting Information [Line Items]
Sales	28,336		29,763		80,350		86,609
Gross profit	9,489		11,719		27,365		34,204
Precision Motion and Technologies
Segment Reporting Information [Line Items]
Sales	41,184		48,941		124,735		152,207
Gross profit	19,660		23,374		60,549		72,599
Unallocated Restructuring Costs
Segment Reporting Information [Line Items]
Gross profit	$ (296)	[1]	$ (508)	[1]	$ (713)	[1]	$ (1,476)	[1]

[1] Corporate costs primarily represent unallocated overhead related to discontinued operations.