Investments in Cash Equivalents and Marketable Securities (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended	12 Months Ended
Jul. 02, 2011	Jul. 02, 2011	Dec. 31, 2010
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	$ 161,639	$ 161,639	$ 151,232
Available For Sale Securities Net Unrealized Gains		2	4
Available For Sale Securities Net Unrealized Losses		0	(2)
Available-for-sale Securities	161,641	161,641	151,234
Available-for-sale Securities, Other Disclosure Items [Abstract]
Maximum Term Of Available For Sale Securities	1	1	1
Marketable Securities, Realized Loss, Other than Temporary Impairments, Amount	0	0
Cash Equivalents [Member] \| Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	34,597	34,597
Available For Sale Securities Net Unrealized Gains		0
Available For Sale Securities Net Unrealized Losses		0
Available-for-sale Securities	34,597	34,597
Cash Equivalents [Member] \| Money Market Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	82,434	82,434	114,217
Available For Sale Securities Net Unrealized Gains		0	0
Available For Sale Securities Net Unrealized Losses		0	0
Available-for-sale Securities	82,434	82,434	114,217
Cash Equivalents [Member] \| US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis			5,500
Available For Sale Securities Net Unrealized Gains			0
Available For Sale Securities Net Unrealized Losses			0
Available-for-sale Securities			5,500
Cash Equivalents [Member] \| Certificates of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis			325
Available For Sale Securities Net Unrealized Gains			0
Available For Sale Securities Net Unrealized Losses			0
Available-for-sale Securities			325
Short Term Marketable Securities [Member] \| Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	1,276	1,276
Available For Sale Securities Net Unrealized Gains		0
Available For Sale Securities Net Unrealized Losses		0
Available-for-sale Securities	1,276	1,276
Short Term Marketable Securities [Member] \| Municipal Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	30,495	30,495
Available For Sale Securities Net Unrealized Gains		0
Available For Sale Securities Net Unrealized Losses		0
Available-for-sale Securities	30,495	30,495
Short Term Marketable Securities [Member] \| US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	8,420	8,420	26,366
Available For Sale Securities Net Unrealized Gains		0	4
Available For Sale Securities Net Unrealized Losses		0	0
Available-for-sale Securities	8,420	8,420	26,370
Short Term Marketable Securities [Member] \| US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	4,057	4,057	3,115
Available For Sale Securities Net Unrealized Gains		2	0
Available For Sale Securities Net Unrealized Losses		0	(2)
Available-for-sale Securities	4,059	4,059	3,113
Short Term Marketable Securities [Member] \| Certificates of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	360	360	1,709
Available For Sale Securities Net Unrealized Gains		0	0
Available For Sale Securities Net Unrealized Losses		0	0
Available-for-sale Securities	$ 360	$ 360	$ 1,709

For an unclassified balance sheet, this item represents investments in debt and equity securities which are categorized neither as held-to-maturity nor trading.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 12
-Subparagraph b
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Staff Position (FSP)
-Number FAS115-1/124-1
-Paragraph 15E
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 22
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Staff Position (FSP)
-Number FAS115-1/124-1
-Paragraph 15D
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 13
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Staff Position (FSP)
-Number FAS115-1/124-1
-Paragraph 15C
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 14
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 16
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6379932&loc=d3e22054-111558

+ Details

- Definition

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.

+ References+ Details