Operating Income (Loss) from Continuing Operations by Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 03, 2015	Jun. 27, 2014	Jul. 03, 2015	Jun. 27, 2014
Operating Income (Loss) from Continuing Operations
Operating Income (Loss) from Continuing Operations	$ 10,315	$ 6,480	$ 15,712	$ 10,548
Laser Products
Operating Income (Loss) from Continuing Operations
Operating Income (Loss) from Continuing Operations	10,046	6,847	18,441	13,971
Vision Technologies
Operating Income (Loss) from Continuing Operations
Operating Income (Loss) from Continuing Operations	(14)	38	(668)	(79)
Precision Motion
Operating Income (Loss) from Continuing Operations
Operating Income (Loss) from Continuing Operations	5,803	4,086	9,940	6,729
Unallocated Corporate and Shared Services
Operating Income (Loss) from Continuing Operations
Operating Income (Loss) from Continuing Operations	$ (5,520)	$ (4,491)	$ (12,001)	$ (10,073)