Cash, Cash Equivalents and Investments (Details 3) (USD $) In Thousands, unless otherwise specified	Jan. 03, 2015	Dec. 28, 2013
Short-term investments
Amortized Cost	$ 90,404	$ 96,462
Gross Unrealized Gains	91	339
Gross Unrealized Losses	(50)	(13)
Fair Value	90,445us-gaap_AvailableForSaleSecurities	96,788us-gaap_AvailableForSaleSecurities
Corporate debt securities [Member]
Short-term investments
Amortized Cost	34,919	37,422
Gross Unrealized Gains	6	30
Gross Unrealized Losses	(31)	(11)
Fair Value	34,894	37,441
Bank certificates of deposit [Member]
Short-term investments
Amortized Cost	21,900	20,300
Gross Unrealized Gains	10	9
Gross Unrealized Losses	0	(1)
Fair Value	21,910	20,308
United States Treasury securities [Member]
Short-term investments
Amortized Cost	19,375	24,219
Gross Unrealized Gains	12	28
Gross Unrealized Losses	(13)	(1)
Fair Value	19,374	24,246
United States government agency securities [Member]
Short-term investments
Amortized Cost	9,209	10,212
Gross Unrealized Gains	3	11
Gross Unrealized Losses	(4)	0
Fair Value	9,208	10,223
Commercial paper [Member]
Short-term investments
Amortized Cost	3,184	2,492
Gross Unrealized Gains	4	1
Gross Unrealized Losses	(2)	0
Fair Value	3,186	2,493
Marketable debt securities [Member]
Short-term investments
Amortized Cost	88,587	94,645
Gross Unrealized Gains	35	79
Gross Unrealized Losses	(50)	(13)
Fair Value	88,572	94,711
Marketable equity securities [Member]
Short-term investments
Amortized Cost	1,817	1,817
Gross Unrealized Gains	56	260
Gross Unrealized Losses	0	0
Fair Value	$ 1,873	$ 2,077

Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale.

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale.

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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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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