Schedule of Fair Value of Financial Assets and Liabilities Measured on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 29, 2013	Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	$ 586,421	$ 667,388
Derivatives	276	121
Total including derivatives	1,159,565	1,006,429
Contingent consideration		388
Liabilities		388
Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and Cash equivalents	147,819	139,354
Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and Cash equivalents	425,049	199,566
U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	211,956	312,116
U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	229,129	217,655
Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	88,891	70,434
Corporate Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	43,982	55,755
Equity And Debt Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	12,122	9,717
Certificates Of Deposit And Time Deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	261	1,627
Non-U.S. Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	80	84
Subtotal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	1,159,289	1,006,308
Quoted Prices in Active Markets for Identical Instruments (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total including derivatives	789,720	644,226
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and Cash equivalents	147,819	139,354
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and Cash equivalents	417,823	183,039
Quoted Prices in Active Markets for Identical Instruments (Level 1) | U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	211,956	312,116
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Equity And Debt Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	12,122	9,717
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Subtotal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	789,720	644,226
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Derivatives	276	121
Total including derivatives	369,845	362,203
Significant Other Observable Inputs (Level 2) | Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and Cash equivalents	7,226	16,527
Significant Other Observable Inputs (Level 2) | U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	229,129	217,655
Significant Other Observable Inputs (Level 2) | Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	88,891	70,434
Significant Other Observable Inputs (Level 2) | Corporate Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	43,982	55,755
Significant Other Observable Inputs (Level 2) | Certificates Of Deposit And Time Deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	261	1,627
Significant Other Observable Inputs (Level 2) | Non-U.S. Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	80	84
Significant Other Observable Inputs (Level 2) | Subtotal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	369,569	362,082
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Contingent consideration		388
Liabilities		$ 388