Sales and Gross Margin for Reportable Segments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 28, 2012	Jun. 29, 2012	Mar. 30, 2012	Dec. 31, 2011	Sep. 30, 2011	Jul. 01, 2011	Apr. 01, 2011	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Segment Reporting Information [Line Items]
Sales	$ 66,413	$ 69,520	$ 70,379	$ 65,186	$ 65,480	$ 78,704	$ 82,609	$ 77,503	$ 271,498		$ 304,296		$ 285,892
Gross profit	27,275	28,853	30,667	27,681	27,773	34,585	37,000	33,742	114,476		133,100		130,614
Laser Products
Segment Reporting Information [Line Items]
Sales									108,186		112,914		105,020
Gross profit									36,582		43,948		43,542
Precision Motion and Technologies
Segment Reporting Information [Line Items]
Sales									163,312		191,382		180,872
Gross profit									78,819		91,142		88,779
Unallocated Restructuring Costs
Segment Reporting Information [Line Items]
Gross profit									$ (925)	[1]	$ (1,990)	[1]	$ (1,707)	[1]

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