Current Liabilities - Warranty Accrual (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 29, 2014	Mar. 30, 2013
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	$ 1,142	$ 2,273
Liabilities accrued for warranties issued	282	518
Warranty claims paid and utilized	(478)	(668)
Changes in accrued warranty liabilities	109	(76)
Balance, end of the period	$ 1,055	$ 2,047