GOODWILL AND INTANGIBLE ASSETS (Details) - USD ($) $ in Thousands	Oct. 03, 2015	Jan. 03, 2015
Goodwill
Goodwill	$ 276,213	$ 269,883
Accumulated impairment losses	(172,359)	(172,359)
Goodwill, total	103,854	97,524
Photonics
Goodwill
Goodwill	98,808	98,808
Accumulated impairment losses	(47,458)	(47,458)
Goodwill, total	51,350	51,350
Lasers
Goodwill
Goodwill	136,091	129,761
Accumulated impairment losses	(104,562)	(104,562)
Goodwill, total	31,529	25,199
Optics
Goodwill
Goodwill	41,314	41,314
Accumulated impairment losses	(20,339)	(20,339)
Goodwill, total	$ 20,975	$ 20,975