Cash, Cash Equivalents and Short-Term Marketable Securities - Cash, Cash Equivalents and Short-Term Marketable Securities (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Apr. 01, 2012	Oct. 02, 2011	Mar. 27, 2011
Cash and cash equivalents
Cash at financial institutions	$ 5,972	$ 5,626
Money market funds	4,451	3,088
Total cash and cash equivalents	10,423	8,714	7,681	15,039
Total short-term marketable securities	187,629	187,668
U.S. government and agency securities [Member]
Cash and cash equivalents
Total short-term marketable securities	47,742	44,236
State and Local Government Securities [Member]
Cash and cash equivalents
Total short-term marketable securities	4,257	590
Corporate bonds and notes [Member]
Cash and cash equivalents
Total short-term marketable securities	72,672	69,234
Asset-backed securities [Member]
Cash and cash equivalents
Total short-term marketable securities	25,333	26,364
Mortgage-backed securities [Member]
Cash and cash equivalents
Total short-term marketable securities	$ 37,625	$ 47,244