Amortized Cost and Fair Market Value of Available for Sale Investments (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 29, 2012	Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 90,623	$ 67,702
Gross Unrealized Gains	1,561	931
Gross Unrealized Losses	7	145
Fair Market Value	92,177	68,488
Money market investments
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,473	1,989
Fair Market Value	2,473	1,989
Mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,396	3,017
Gross Unrealized Gains	115	61
Gross Unrealized Losses	1	18
Fair Market Value	2,510	3,060
Corporate bonds and direct obligations of government agencies
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	68,962	51,014
Gross Unrealized Gains	1,395	819
Gross Unrealized Losses	6	126
Fair Market Value	70,351	51,707
U.S. Treasury Obligations
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	16,792	11,682
Gross Unrealized Gains	51	51
Gross Unrealized Losses		1
Fair Market Value	$ 16,843	$ 11,732

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