Schedule of Reported Financial Assets and Liabilities (Detail) (Fair Value, Measurements, Recurring, USD $) In Thousands, unless otherwise specified	Mar. 30, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	$ 967,053	$ 1,199,751
Liabilities	2,230	2,230
Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	232,626	341,638
Marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	462,150	586,882
Long-term marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	272,068	271,078
Other current assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	209	153
Long-term other accrued liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	2,230	2,230
Quoted Prices in Active Markets for Identical Instruments (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	555,083	764,158
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	219,616	283,107
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	214,230	371,101
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Long-term marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	121,237	109,950
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	411,970	435,593
Significant Other Observable Inputs (Level 2) | Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	13,010	58,531
Significant Other Observable Inputs (Level 2) | Marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	247,920	215,781
Significant Other Observable Inputs (Level 2) | Long-term marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	150,831	161,128
Significant Other Observable Inputs (Level 2) | Other current assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	209	153
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	2,230	2,230
Significant Unobservable Inputs (Level 3) | Long-term other accrued liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	$ 2,230	$ 2,230