Fair Value Hierarchy for Financial Assets Measured at Fair Value on Recurring Basis (Detail) (Fair Value, Measurements, Recurring, USD $) In Thousands, unless otherwise specified	Dec. 29, 2012	Mar. 31, 2012
Money Market Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	$ 2,712	$ 5,244
Government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	48,200	67,261
Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	44,266	83,645
Corporate Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	18,090	20,121
Municipal Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	1,048
Forward purchase or (sale) contracts | Japanese Yen
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	429	202
Forward purchase or (sale) contracts | New Taiwan Dollar
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	(2)	(5)
Forward purchase or (sale) contracts | Korean Won
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	26	(17)
Forward purchase or (sale) contracts | Euro
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	(67)	(1)
Forward purchase or (sale) contracts | British Pound
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	28	20
Forward purchase or (sale) contracts | Chinese Renminbi
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	(32)	(1)
Forward purchase or (sale) contracts | Singapore Dollar
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	(2)
Level 1 | Money Market Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	2,712	5,244
Level 2 | Government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	48,200	67,261
Level 2 | Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	44,266	83,645
Level 2 | Corporate Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	18,090	20,121
Level 2 | Municipal Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	1,048
Level 2 | Forward purchase or (sale) contracts | Japanese Yen
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	429	202
Level 2 | Forward purchase or (sale) contracts | New Taiwan Dollar
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	(2)	(5)
Level 2 | Forward purchase or (sale) contracts | Korean Won
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	26	(17)
Level 2 | Forward purchase or (sale) contracts | Euro
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	(67)	(1)
Level 2 | Forward purchase or (sale) contracts | British Pound
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	28	20
Level 2 | Forward purchase or (sale) contracts | Chinese Renminbi
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	(32)	(1)
Level 2 | Forward purchase or (sale) contracts | Singapore Dollar
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	$ (2)