Accrued Warranty (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Oct. 02, 2015
Product Warranties Disclosures [Abstract]
Balance at beginning of the period	$ 3,335	$ 3,044
Provision charged to cost of revenue	1,050	1,878
Acquisition related warranty accrual		94
Use of provision	(1,060)	(1,084)
Divestiture of JK Lasers		(392)
Foreign currency exchange rate changes	(25)	(11)
Balance at end of period	$ 3,300	$ 3,529