Schedule of Unrealized Loss on Available for Sale Investments (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 29, 2013	Dec. 29, 2012
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments with unrealized losses, Less than 12 months, Fair Value	$ 38,630	$ 4,157
Available-for-sale investments with unrealized losses, Less than 12 months, Unrealized Loss	643	7
Available-for-sale investments with unrealized losses, 12 months or longer, Fair Value
Available-for-sale investments with unrealized losses, 12 months or longer, Unrealized Loss
Available-for-sale investments with unrealized losses, Fair Value, Total	38,630	4,157
Available-for-sale investments with unrealized losses, Unrealized Loss, Total	643	7
Asset-backed securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments with unrealized losses, Less than 12 months, Fair Value	4,074
Available-for-sale investments with unrealized losses, Less than 12 months, Unrealized Loss	112
Available-for-sale investments with unrealized losses, 12 months or longer, Fair Value
Available-for-sale investments with unrealized losses, 12 months or longer, Unrealized Loss
Available-for-sale investments with unrealized losses, Fair Value, Total	4,074
Available-for-sale investments with unrealized losses, Unrealized Loss, Total	112
Corporate bonds and direct obligations of government agencies
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments with unrealized losses, Less than 12 months, Fair Value	33,801	3,387
Available-for-sale investments with unrealized losses, Less than 12 months, Unrealized Loss	517	6
Available-for-sale investments with unrealized losses, 12 months or longer, Fair Value
Available-for-sale investments with unrealized losses, 12 months or longer, Unrealized Loss
Available-for-sale investments with unrealized losses, Fair Value, Total	33,801	3,387
Available-for-sale investments with unrealized losses, Unrealized Loss, Total	517	6
U.S. Treasury Obligations
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments with unrealized losses, Less than 12 months, Fair Value	755	770
Available-for-sale investments with unrealized losses, Less than 12 months, Unrealized Loss	14	1
Available-for-sale investments with unrealized losses, 12 months or longer, Fair Value
Available-for-sale investments with unrealized losses, 12 months or longer, Unrealized Loss
Available-for-sale investments with unrealized losses, Fair Value, Total	755	770
Available-for-sale investments with unrealized losses, Unrealized Loss, Total	$ 14	$ 1