Fair Value Hierarchy for Financial Assets Measured at Fair Value on Recurring Basis (Detail) (Fair Value, Measurements, Recurring, USD $) In Thousands, unless otherwise specified	Sep. 29, 2012	Mar. 31, 2012
Money Market Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	$ 12,761	$ 5,244
Government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	83,056	67,261
Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	30,346	83,645
Corporate Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	22,797	20,121
Forward purchase or (sale) contracts | Japanese Yen
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	(87)	202
Forward purchase or (sale) contracts | Taiwan Dollar
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	15	(5)
Forward purchase or (sale) contracts | Korean Won
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	40	(17)
Forward purchase or (sale) contracts | Euro
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	(90)	(1)
Forward purchase or (sale) contracts | British Pound
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	63	20
Forward purchase or (sale) contracts | Singapore Dollar
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	15
Forward purchase or (sale) contracts | Chinese Renminbi
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets		(1)
Level 1 | Money Market Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	12,761	5,244
Level 2 | Government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	83,056	67,261
Level 2 | Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	30,346	83,645
Level 2 | Corporate Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	22,797	20,121
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	(87)	202
Level 2 | Forward purchase or (sale) contracts | Taiwan Dollar
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of financial assets	15	(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	40	(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	(90)	(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	63	20
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	15
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		$ (1)