Fair Value of Financial Instruments (Details) (USD $) In Thousands	Jul. 02, 2011	Jan. 01, 2011
Financial assets and liabilities measured at fair value on a recurring basis
Total cash equivalents	$ 134,824	$ 138,567
Total short-term investments	198,766	227,295
Money market funds | Assets and liabilities measured at fair value on recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial assets and liabilities measured at fair value on a recurring basis
Total cash equivalents	98,736	45,167
Money market funds | Assets and liabilities measured at fair value on recurring basis | Fair Value
Financial assets and liabilities measured at fair value on a recurring basis
Total cash equivalents	98,736	45,167
U.S. Treasury bills | Assets and liabilities measured at fair value on recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial assets and liabilities measured at fair value on a recurring basis
Total cash equivalents		50,097
Total short-term investments	11,898	6,999
U.S. Treasury bills | Assets and liabilities measured at fair value on recurring basis | Fair Value
Financial assets and liabilities measured at fair value on a recurring basis
Total cash equivalents		50,097
Total short-term investments	11,898	6,999
Corporate bonds | Assets and liabilities measured at fair value on recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial assets and liabilities measured at fair value on a recurring basis
Total short-term investments	81,232	88,518
Corporate bonds | Assets and liabilities measured at fair value on recurring basis | Fair Value
Financial assets and liabilities measured at fair value on a recurring basis
Total short-term investments	81,232	88,518
Variable-rate demand notes | Assets and liabilities measured at fair value on recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial assets and liabilities measured at fair value on a recurring basis
Total short-term investments	36,725	39,425
Variable-rate demand notes | Assets and liabilities measured at fair value on recurring basis | Fair Value
Financial assets and liabilities measured at fair value on a recurring basis
Total short-term investments	36,725	39,425
U.S. government agency | Assets and liabilities measured at fair value on recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial assets and liabilities measured at fair value on a recurring basis
Total cash equivalents	998
Total short-term investments	10,070	34,680
U.S. government agency | Assets and liabilities measured at fair value on recurring basis | Fair Value
Financial assets and liabilities measured at fair value on a recurring basis
Total cash equivalents	998
Total short-term investments	10,070	34,680
Municipal bonds | Assets and liabilities measured at fair value on recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial assets and liabilities measured at fair value on a recurring basis
Total short-term investments	47,454	38,414
Municipal bonds | Assets and liabilities measured at fair value on recurring basis | Fair Value
Financial assets and liabilities measured at fair value on a recurring basis
Total short-term investments	47,454	38,414
International government bonds | Assets and liabilities measured at fair value on recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial assets and liabilities measured at fair value on a recurring basis
Total short-term investments	7,819	10,830
International government bonds | Assets and liabilities measured at fair value on recurring basis | Fair Value
Financial assets and liabilities measured at fair value on a recurring basis
Total short-term investments	7,819	10,830
Certificates of deposit | Assets and liabilities measured at fair value on recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial assets and liabilities measured at fair value on a recurring basis
Total short-term investments	1,570	5,742
Certificates of deposit | Assets and liabilities measured at fair value on recurring basis | Fair Value
Financial assets and liabilities measured at fair value on a recurring basis
Total short-term investments	1,570	5,742
Commercial paper | Assets and liabilities measured at fair value on recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial assets and liabilities measured at fair value on a recurring basis
Total cash equivalents	500	2,659
Total short-term investments	1,998	2,687
Commercial paper | Assets and liabilities measured at fair value on recurring basis | Fair Value
Financial assets and liabilities measured at fair value on a recurring basis
Total cash equivalents	500	2,659
Total short-term investments	1,998	2,687
Auction rate securities | Assets and liabilities measured at fair value on recurring basis | Significant Unobservable Inputs (Level 3)
Financial assets and liabilities measured at fair value on a recurring basis
Total long-term investments	17,196	17,500
Auction rate securities | Assets and liabilities measured at fair value on recurring basis | Fair Value
Financial assets and liabilities measured at fair value on a recurring basis
Total long-term investments	17,196	17,500
Assets and liabilities measured at fair value on recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial assets and liabilities measured at fair value on a recurring basis
Total cash equivalents	100,234	97,923
Total short-term investments	198,766	227,295
Total assets at fair value	299,000	325,218
Assets and liabilities measured at fair value on recurring basis | Significant Other Observable Inputs (Level 2)
Financial assets and liabilities measured at fair value on a recurring basis
Derivative instruments	2,941	3,811
Total liabilities at fair value	2,941	3,811
Assets and liabilities measured at fair value on recurring basis | Significant Unobservable Inputs (Level 3)
Financial assets and liabilities measured at fair value on a recurring basis
Total long-term investments	17,196	17,500
Total assets at fair value	17,196	17,500
Contingent consideration	2,034	1,780
Total liabilities at fair value	2,034	1,780
Assets and liabilities measured at fair value on recurring basis | Fair Value
Financial assets and liabilities measured at fair value on a recurring basis
Total cash equivalents	100,234	97,923
Total short-term investments	198,766	227,295
Total long-term investments	17,196	17,500
Total assets at fair value	316,196	342,718
Derivative instruments	2,941	3,811
Contingent consideration	2,034	1,780
Total liabilities at fair value	$ 4,975	$ 5,591