Cash Equivalents and Investments (Details) (Fair Value, Measurements, Recurring [Member], USD $) In Thousands	Oct. 02, 2011	Dec. 31, 2010
Company's cash equivalents and investments measured at fair value
Cash equivalents measured at fair value	$ 633,492	$ 380,382
Investments measured at fair value	153,719	154,880
Fair Value Measurements Level 1 [Member] \| Money Market Funds [Member]
Company's cash equivalents and investments measured at fair value
Cash equivalents measured at fair value	632,707	378,382
Fair Value Measurements Level 1 [Member] \| Asset-backed and mortgage-backed securities [Member]
Company's cash equivalents and investments measured at fair value
Investments measured at fair value	0	0
Fair Value Measurements Level 1 [Member] \| U.S. government and agency securities [Member]
Company's cash equivalents and investments measured at fair value
Cash equivalents measured at fair value	0	2,000
Investments measured at fair value	4,830	1,496
Fair Value Measurements Level 1 [Member] \| Corporate debt securities [Member]
Company's cash equivalents and investments measured at fair value
Investments measured at fair value	0	0
Fair Value Measurements Level 1 [Member] \| Long-term marketable equity securities [Member]
Company's cash equivalents and investments measured at fair value
Investments measured at fair value	1,382	1,681
Fair Value Measurements Level 1 [Member]
Company's cash equivalents and investments measured at fair value
Cash equivalents measured at fair value	632,707	380,382
Investments measured at fair value	4,830	1,496
Fair Value Measurements Level 2 [Member] \| Money Market Funds [Member]
Company's cash equivalents and investments measured at fair value
Cash equivalents measured at fair value	0	0
Fair Value Measurements Level 2 [Member] \| Asset-backed and mortgage-backed securities [Member]
Company's cash equivalents and investments measured at fair value
Investments measured at fair value	108,970	116,552
Fair Value Measurements Level 2 [Member] \| U.S. government and agency securities [Member]
Company's cash equivalents and investments measured at fair value
Cash equivalents measured at fair value	785	0
Investments measured at fair value	26,187	24,502
Fair Value Measurements Level 2 [Member] \| Corporate debt securities [Member]
Company's cash equivalents and investments measured at fair value
Investments measured at fair value	13,732	12,330
Fair Value Measurements Level 2 [Member] \| Long-term marketable equity securities [Member]
Company's cash equivalents and investments measured at fair value
Investments measured at fair value	0	0
Fair Value Measurements Level 2 [Member]
Company's cash equivalents and investments measured at fair value
Cash equivalents measured at fair value	785	0
Investments measured at fair value	148,889	153,384
Fair Value Measurements Level 3 [Member] \| Money Market Funds [Member]
Company's cash equivalents and investments measured at fair value
Cash equivalents measured at fair value	0	0
Fair Value Measurements Level 3 [Member] \| Asset-backed and mortgage-backed securities [Member]
Company's cash equivalents and investments measured at fair value
Investments measured at fair value	0	0
Fair Value Measurements Level 3 [Member] \| U.S. government and agency securities [Member]
Company's cash equivalents and investments measured at fair value
Cash equivalents measured at fair value	0	0
Investments measured at fair value	0	0
Fair Value Measurements Level 3 [Member] \| Corporate debt securities [Member]
Company's cash equivalents and investments measured at fair value
Investments measured at fair value	0	0
Fair Value Measurements Level 3 [Member] \| Long-term marketable equity securities [Member]
Company's cash equivalents and investments measured at fair value
Investments measured at fair value	0	0
Fair Value Measurements Level 3 [Member]
Company's cash equivalents and investments measured at fair value
Cash equivalents measured at fair value	0	0
Investments measured at fair value	0	0
Money Market Funds [Member]
Company's cash equivalents and investments measured at fair value
Cash equivalents measured at fair value	632,707	378,382
Asset-backed and mortgage-backed securities [Member]
Company's cash equivalents and investments measured at fair value
Investments measured at fair value	108,970	116,552
U.S. government and agency securities [Member]
Company's cash equivalents and investments measured at fair value
Cash equivalents measured at fair value	785	2,000
Investments measured at fair value	31,017	25,998
Corporate debt securities [Member]
Company's cash equivalents and investments measured at fair value
Investments measured at fair value	13,732	12,330
Long-term marketable equity securities [Member]
Company's cash equivalents and investments measured at fair value
Investments measured at fair value	$ 1,382	$ 1,681

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the Company may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months.