Schedule of Reported Financial Assets and Liabilities (Detail) (Fair Value, Measurements, Recurring, USD $) In Thousands, unless otherwise specified	Jun. 29, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	$ 1,107,141	$ 1,199,751
Liabilities	2,536	2,230
Other Accrued Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	306
Other current assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets		153
Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	254,625	341,638
Marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	488,439	586,882
Long-term marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	364,077	271,078
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	263,323	296,263
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	248,882	283,107
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	14,441	13,156
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	843,818	903,488
Liabilities	306
Significant Other Observable Inputs (Level 2) | Other Accrued Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities	306
Significant Other Observable Inputs (Level 2) | Other current assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets		153
Significant Other Observable Inputs (Level 2) | Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	5,743	58,531
Significant Other Observable Inputs (Level 2) | Marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	488,439	586,882
Significant Other Observable Inputs (Level 2) | Long-term marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets	349,636	257,922
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