Accrued Warranty (Details) - USD ($) $ in Thousands	9 Months Ended
	Oct. 02, 2015	Sep. 26, 2014
Product Warranties Disclosures [Abstract]
Balance at beginning of the period	$ 3,044	$ 3,315
Provision charged to cost of revenue	1,878	1,361
Acquisition related warranty accrual	94	90
Use of provision	(1,084)	(1,529)
Divestiture of JK Lasers	(392)
Foreign currency exchange rate changes	(11)	(14)
Balance at end of period	$ 3,529	$ 3,223