Cash and Investments (Details) (USD $) In Thousands, unless otherwise specified	Mar. 30, 2013	Dec. 29, 2012
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 95,279	$ 109,910
Gross Unrealized Gains	15	10
Gross Unrealized Losses	(10)	(12)
Estimated Fair Market Value	95,284	109,908
Cash and Cash equivalents [Member] \| Cash [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	45,532	60,206
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Market Value	45,532	60,206
Cash and Cash equivalents [Member] \| Money market funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	413	109
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Market Value	413	109
Cash and Cash equivalents [Member] \| Commercial paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,400	2,600
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Market Value	1,400	2,600
Short-term investments [Member] \| Commercial paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,400	3,199
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Market Value	2,400	3,199
Short-term investments [Member] \| US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	4,998	4,996
Gross Unrealized Gains	1	1
Gross Unrealized Losses	0	0
Estimated Fair Market Value	4,999	4,997
Short-term investments [Member] \| US Government agency securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	15,502	15,567
Gross Unrealized Gains	4	6
Gross Unrealized Losses	(1)	(2)
Estimated Fair Market Value	15,505	15,571
Short-term investments [Member] \| Municipal securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	6,313	5,396
Gross Unrealized Gains	4	1
Gross Unrealized Losses	(1)	(1)
Estimated Fair Market Value	6,316	5,396
Short-term investments [Member] \| Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	18,721	17,837
Gross Unrealized Gains	6	2
Gross Unrealized Losses	(8)	(9)
Estimated Fair Market Value	$ 18,719	$ 17,830

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

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- Definition

This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

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