Operating Income (Loss) from Continuing Operations by Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 01, 2016	Apr. 03, 2015
Operating Income (Loss) from Continuing Operations
Operating Income (Loss) from Continuing Operations	$ 2,587	$ 5,397
Laser Products
Operating Income (Loss) from Continuing Operations
Operating Income (Loss) from Continuing Operations	6,856	8,395
Vision Technologies
Operating Income (Loss) from Continuing Operations
Operating Income (Loss) from Continuing Operations	(3,771)	(654)
Precision Motion
Operating Income (Loss) from Continuing Operations
Operating Income (Loss) from Continuing Operations	5,235	4,137
Unallocated Corporate and Shared Services
Operating Income (Loss) from Continuing Operations
Operating Income (Loss) from Continuing Operations	$ (5,733)	$ (6,481)