Cash, Cash Equivalents and Investments (Details 3) - USD ($) $ in Thousands	Dec. 31, 2016	Jan. 02, 2016
Short-term investments
Amortized Cost		$ 94,287
Gross Unrealized Gains		380
Gross Unrealized Losses		(169)
Fair Value		94,498
Corporate debt securities [Member]
Short-term investments
Amortized Cost		34,905
Gross Unrealized Gains		1
Gross Unrealized Losses		(77)
Fair Value		34,829
Bank certificates of deposit [Member]
Short-term investments
Amortized Cost		15,049
Gross Unrealized Gains		1
Gross Unrealized Losses		(4)
Fair Value		15,046
United States Treasury securities [Member]
Short-term investments
Amortized Cost		36,372
Gross Unrealized Gains		2
Gross Unrealized Losses		(88)
Fair Value		36,286
United States government agency securities [Member]
Short-term investments
Amortized Cost		4,151
Gross Unrealized Gains		1
Gross Unrealized Losses		0
Fair Value		4,152
Commercial paper [Member]
Short-term investments
Amortized Cost		1,993
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Fair Value		1,993
Marketable debt securities [Member]
Short-term investments
Amortized Cost		92,470
Gross Unrealized Gains		5
Gross Unrealized Losses		(169)
Fair Value		92,306
Marketable equity securities [Member]
Short-term investments
Amortized Cost	$ 2,131	1,817
Gross Unrealized Gains	926	375
Gross Unrealized Losses	0	0
Fair Value	$ 3,057	$ 2,192

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
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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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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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