Amortized Cost and Fair Value of Available for Sale Investments (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 30, 2013	Dec. 29, 2012
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 101,313	$ 90,995
Gross Unrealized Gains	1,322	1,414
Gross Unrealized Losses	4	7
Fair Value	102,631	92,402
Money market investments
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	12,956	2,865
Fair Value	12,956	2,865
Mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,094	2,175
Gross Unrealized Gains	61	73
Fair Value	2,155	2,248
Corporate bonds and direct obligations of government agencies
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	67,473	69,173
Gross Unrealized Gains	1,217	1,294
Gross Unrealized Losses	4	6
Fair Value	68,686	70,461
U.S. Treasury Obligations
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	18,790	16,782
Gross Unrealized Gains	44	47
Gross Unrealized Losses		1
Fair Value	$ 18,834	$ 16,828

Amount of debt securities categorized neither as held-to-maturity nor trading.

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Reference 9: http://www.xbrl.org/2003/role/presentationRef

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+ Details

- Definition

This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

+ References+ Details