Cash, Cash Equivalents and Investments (Details 3) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 28, 2013	Dec. 29, 2012
Short-term investments
Amortized Cost	$ 96,462	$ 100,170
Gross Unrealized Gains	339	545
Gross Unrealized Losses	(13)	(11)
Fair Value	96,788	100,704
Corporate debt securities [Member]
Short-term investments
Amortized Cost	37,422	31,313
Gross Unrealized Gains	30	57
Gross Unrealized Losses	(11)	(11)
Fair Value	37,441	31,359
Bank certificates of deposit [Member]
Short-term investments
Amortized Cost	20,300	27,805
Gross Unrealized Gains	9	21
Gross Unrealized Losses	(1)	0
Fair Value	20,308	27,826
United States Treasury securities [Member]
Short-term investments
Amortized Cost	24,219	23,213
Gross Unrealized Gains	28	26
Gross Unrealized Losses	(1)	0
Fair Value	24,246	23,239
United States government agency securities [Member]
Short-term investments
Amortized Cost	10,212	10,245
Gross Unrealized Gains	11	13
Gross Unrealized Losses	0	0
Fair Value	10,223	10,258
Commercial paper [Member]
Short-term investments
Amortized Cost	2,492	5,777
Gross Unrealized Gains	1	6
Gross Unrealized Losses	0	0
Fair Value	2,493	5,783
Marketable debt securities [Member]
Short-term investments
Amortized Cost	94,645	98,353
Gross Unrealized Gains	79	123
Gross Unrealized Losses	(13)	(11)
Fair Value	94,711	98,465
Marketable equity securities [Member]
Short-term investments
Amortized Cost	1,817	1,817
Gross Unrealized Gains	260	422
Gross Unrealized Losses	0	0
Fair Value	$ 2,077	$ 2,239