Cash and Investments (Details) (USD $) In Thousands, unless otherwise specified	Mar. 29, 2014	Dec. 28, 2013
Cash and Cash equivalents [Member] | Cash [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 38,247	$ 43,139
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Market Value	38,247	43,139
Cash and Cash equivalents [Member] | Money market funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	586	876
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Market Value	586	876
Cash and Cash equivalents [Member] | Commercial paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		750
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Estimated Fair Market Value		750
Short-term investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	88,028	92,853
Gross Unrealized Gains	19	22
Gross Unrealized Losses	(10)	(13)
Estimated Fair Market Value	88,037	92,862
Short-term investments [Member] | Commercial paper and corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	800
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Estimated Fair Market Value	800
Short-term investments [Member] | US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	5,022	5,036
Gross Unrealized Gains	1	0
Gross Unrealized Losses	0	0
Estimated Fair Market Value	5,023	5,036
Short-term investments [Member] | US Government Agencies Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	11,768	11,980
Gross Unrealized Gains	6	4
Gross Unrealized Losses	(2)	(4)
Estimated Fair Market Value	11,772	11,980
Short-term investments [Member] | Municipal securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	10,367	9,756
Gross Unrealized Gains	7	11
Gross Unrealized Losses	(1)	(4)
Estimated Fair Market Value	10,373	9,763
Short-term investments [Member] | Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	21,238	21,316
Gross Unrealized Gains	5	7
Gross Unrealized Losses	(7)	(5)
Estimated Fair Market Value	$ 21,236	$ 21,318