Current Liabilities - Warranty Accrual (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 02, 2016	Apr. 04, 2015
Accounts Payable and Accrued Liabilities, Current [Abstract]
New product warranty period	12 months
Refurbished product warranty period	3 months
Movement in Standard and Extended Product Warranty, Increase (Decrease) [Roll Forward]
Balance, beginning of the period	$ 1,586
Liabilities accrued for warranties issued	653	$ 615
Warranty claims paid and utilized	(548)	(629)
Changes in accrued warranty liabilities	(21)	250
Balance, end of the period	$ 1,670	$ 1,586