Cash, Cash Equivalents and Investments (Details 2) (USD $) In Thousands, unless otherwise specified	Mar. 30, 2013	Dec. 29, 2012
Short-term investments
Amortized Cost	$ 100,738	$ 100,170
Gross Unrealized Gains	261	545
Gross Unrealized Losses	(7)	(11)
Fair Value	100,992	100,704
Corporate Debt Securities [Member]
Short-term investments
Amortized Cost	34,409	31,313
Gross Unrealized Gains	51	57
Gross Unrealized Losses	(7)	(11)
Fair Value	34,453	31,359
Certificates of Deposit [Member]
Short-term investments
Amortized Cost	24,800	27,805
Gross Unrealized Gains	27	21
Gross Unrealized Losses	0	0
Fair Value	24,827	27,826
US Treasury Securities [Member]
Short-term investments
Amortized Cost	21,198	23,213
Gross Unrealized Gains	27	26
Gross Unrealized Losses	0	0
Fair Value	21,225	23,239
US Government Corporations and Agencies Securities [Member]
Short-term investments
Amortized Cost	14,231	10,245
Gross Unrealized Gains	15	13
Gross Unrealized Losses	0	0
Fair Value	14,246	10,258
Commercial Paper [Member]
Short-term investments
Amortized Cost	4,283	5,777
Gross Unrealized Gains	7	6
Gross Unrealized Losses	0	0
Fair Value	4,290	5,783
Marketable Debt Securities [Member]
Short-term investments
Amortized Cost	98,921	98,353
Gross Unrealized Gains	127	123
Gross Unrealized Losses	(7)	(11)
Fair Value	99,041	98,465
Marketable Equity Securities [Member]
Short-term investments
Amortized Cost	1,817	1,817
Gross Unrealized Gains	134	422
Gross Unrealized Losses	0	0
Fair Value	$ 1,951	$ 2,239

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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