Acquired Intangible Assets and Goodwill (Details) (USD $) In Thousands, unless otherwise specified	Dec. 28, 2013	Dec. 29, 2012
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross Carrying Amount	$ 35,776	$ 33,498
Finite-Lived Intangible Assets, Accumulated Amortization	23,023	20,579
Patents [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross Carrying Amount	24,356	23,306
Finite-Lived Intangible Assets, Accumulated Amortization	17,730	15,487
Consulting Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross Carrying Amount	976	976
Finite-Lived Intangible Assets, Accumulated Amortization	976	976
Non-compete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross Carrying Amount	2,652	2,347
Finite-Lived Intangible Assets, Accumulated Amortization	2,243	2,174
Customer Lists [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross Carrying Amount	2,621	1,989
Finite-Lived Intangible Assets, Accumulated Amortization	1,952	1,820
Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross Carrying Amount	5,171	4,880
Finite-Lived Intangible Assets, Accumulated Amortization	$ 122	$ 122