Acquisitions - Purchase Price Allocation Tables (Details) (USD $) In Thousands, unless otherwise specified	Dec. 29, 2012 InMoTx, Inc. [Member]	Jan. 10, 2011 InMoTx, Inc. [Member]	Dec. 29, 2012 MobileRobots [Member]	Jun. 25, 2010 MobileRobots [Member]
Business Acquisition [Line Items]
Current assets	$ 88		$ 1,196
Property and equipment	60		91
Inventory	370
Other long-term assets	14
Intangible assets	1,331	1,331	1,170	1,186
Goodwill	1,440	1,440	1,186	1,170
Total assets acquired	3,303		3,643
Current liabilities	681		515
Long-term debt	54		10
Total liabilities assumed	735		525
Net assets acquired	$ 2,568		$ 3,118