Fair Value Of Financial Instruments (Schedule Of Fair Value Of Financial Assets) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Mar. 26, 2011
Cash Equivalents [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of financial assets	$ 57,621	$ 33,199
Cash Equivalents [Member] | Quoted Prices In Active Markets For Identical Assets Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of financial assets	40,557	17,700
Cash Equivalents [Member] | Significant Other Observable Inputs Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of financial assets	17,064	15,499
Cash Equivalents [Member] | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of financial assets	1,112
Cash Equivalents [Member] | Corporate Debt Securities [Member] | Significant Other Observable Inputs Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of financial assets	1,112
Cash Equivalents [Member] | Money-Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of financial assets	40,557	17,700
Cash Equivalents [Member] | Money-Market Funds [Member] | Quoted Prices In Active Markets For Identical Assets Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of financial assets	40,557	17,700
Cash Equivalents [Member] | U.S. Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of financial assets		10,500
Cash Equivalents [Member] | U.S. Treasury Securities [Member] | Significant Other Observable Inputs Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of financial assets		10,500
Cash Equivalents [Member] | Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of financial assets	15,952	4,999
Cash Equivalents [Member] | Commercial Paper [Member] | Significant Other Observable Inputs Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of financial assets	15,952	4,999
Available-for-sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of financial assets	118,791	172,230
Available-for-sale Securities [Member] | Quoted Prices In Active Markets For Identical Assets Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of financial assets	30,261	35,281
Available-for-sale Securities [Member] | Significant Other Observable Inputs Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of financial assets	88,530	136,949
Available-for-sale Securities [Member] | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of financial assets	48,025	64,212
Available-for-sale Securities [Member] | Corporate Debt Securities [Member] | Significant Other Observable Inputs Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of financial assets	48,025	64,212
Available-for-sale Securities [Member] | U.S. Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of financial assets	30,261	35,281
Available-for-sale Securities [Member] | U.S. Treasury Securities [Member] | Quoted Prices In Active Markets For Identical Assets Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of financial assets	30,261	35,281
Available-for-sale Securities [Member] | Agency Discount Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of financial assets	16,796	16,591
Available-for-sale Securities [Member] | Agency Discount Notes [Member] | Significant Other Observable Inputs Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of financial assets	16,796	16,591
Available-for-sale Securities [Member] | Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of financial assets	23,709	56,146
Available-for-sale Securities [Member] | Commercial Paper [Member] | Significant Other Observable Inputs Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of financial assets	$ 23,709	$ 56,146