Fair Value Measurement (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Jan. 01, 2012 Contingent Consideration [Member]	Jan. 01, 2012 Measured on a Recurring Basis [Member]	Apr. 03, 2011 Measured on a Recurring Basis [Member]	Jan. 01, 2012 Measured on a Recurring Basis [Member] Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]	Apr. 03, 2011 Measured on a Recurring Basis [Member] Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]	Jan. 01, 2012 Measured on a Recurring Basis [Member] Significant Other Observable Inputs (Level 2) [Member]	Apr. 03, 2011 Measured on a Recurring Basis [Member] Significant Other Observable Inputs (Level 2) [Member]	Jan. 01, 2012 Measured on a Recurring Basis [Member] Significant Unobservable Inputs (Level 3) [Member]	Apr. 03, 2011 Measured on a Recurring Basis [Member] Significant Unobservable Inputs (Level 3) [Member]
Cash Equivalents and Short-Term Investments:
US government treasuries and agencies securities		$ 157,279	$ 119,926	$ 157,279	$ 119,926	$ 0	$ 0	$ 0	$ 0
Money market funds		61,259	32,203	61,259	32,203	0	0	0	0
Corporate commercial paper		8,494	51,785	0	0	8,494	51,785	0	0
Corporate bonds		38,088	57,087	0	0	38,088	57,087	0	0
Bank deposits		22,133	17,764	0	0	22,133	17,764	0	0
Municipal bonds		580	369	0	0	580	369	0	0
Total assets measured at fair value		287,833	279,134	218,538	152,129	69,295	127,005	0	0
Change in fair value of liabilities measured using Level 3 inputs [Roll Forward]
Beginning balance	1,800
Additions	0
Settlements	(1,800)
Ending balance	$ 0