Cash, Cash Equivalents and Investments (Details 2) - USD ($) $ in Thousands	Oct. 03, 2015	Jan. 03, 2015
Short-term investments
Amortized Cost	$ 95,049	$ 90,404
Gross Unrealized Gains	127	91
Gross Unrealized Losses	(72)	(50)
Fair Value	95,104	90,445
Corporate debt securities [Member]
Short-term investments
Amortized Cost	34,504	34,919
Gross Unrealized Gains	14	6
Gross Unrealized Losses	(16)	(31)
Fair Value	34,502	34,894
Bank certificates of deposit [Member]
Short-term investments
Amortized Cost	12,500	21,900
Gross Unrealized Gains	7	10
Gross Unrealized Losses	0	0
Fair Value	12,507	21,910
United States Treasury securities [Member]
Short-term investments
Amortized Cost	36,880	19,375
Gross Unrealized Gains	100	12
Gross Unrealized Losses	0	(13)
Fair Value	36,980	19,374
United States government agency securities [Member]
Short-term investments
Amortized Cost	6,154	9,209
Gross Unrealized Gains	2	3
Gross Unrealized Losses	0	(4)
Fair Value	6,156	9,208
Commercial paper [Member]
Short-term investments
Amortized Cost	3,194	3,184
Gross Unrealized Gains	4	4
Gross Unrealized Losses	0	(2)
Fair Value	3,198	3,186
Marketable debt securities [Member]
Short-term investments
Amortized Cost	93,232	88,587
Gross Unrealized Gains	127	35
Gross Unrealized Losses	(16)	(50)
Fair Value	93,343	88,572
Marketable equity securities [Member]
Short-term investments
Amortized Cost	1,817	1,817
Gross Unrealized Gains	0	56
Gross Unrealized Losses	(56)	0
Fair Value	$ 1,761	$ 1,873