Schedule of Unrealized Loss on Available for Sale Investments (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 28, 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	$ 26,355	$ 4,157
Available-for-sale investments with unrealized losses, Less than 12 months, Unrealized Loss	455	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	26,355	4,157
Available-for-sale investments with unrealized losses, Unrealized Loss, Total	455	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	3,429
Available-for-sale investments with unrealized losses, Less than 12 months, Unrealized Loss	72
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	3,429
Available-for-sale investments with unrealized losses, Unrealized Loss, Total	72
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	22,169	3,387
Available-for-sale investments with unrealized losses, Less than 12 months, Unrealized Loss	370	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	22,169	3,387
Available-for-sale investments with unrealized losses, Unrealized Loss, Total	370	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	757	770
Available-for-sale investments with unrealized losses, Less than 12 months, Unrealized Loss	13	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	757	770
Available-for-sale investments with unrealized losses, Unrealized Loss, Total	$ 13	$ 1