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