Cash, Cash Equivalents and Short-Term Marketable Securities - Cash, Cash Equivalents and Short-Term Marketable Securities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 30, 2012	Apr. 01, 2012	Jan. 01, 2012	Mar. 27, 2011
Cash and cash equivalents
Cash at financial institutions	$ 6,155	$ 5,626
Money market funds	9,179	3,088
Total cash and cash equivalents	15,334	8,714	9,745	15,039
Total short-term marketable securities	185,784	187,668
U.S. government and agency securities [Member]
Cash and cash equivalents
Total short-term marketable securities	50,145	44,236
State and local government securities [Member]
Cash and cash equivalents
Total short-term marketable securities	3,572	590
Corporate bonds and notes [Member]
Cash and cash equivalents
Total short-term marketable securities	72,267	69,234
Asset-backed securities [Member]
Cash and cash equivalents
Total short-term marketable securities	27,972	26,364
Mortgage-backed securities [Member]
Cash and cash equivalents
Total short-term marketable securities	$ 31,828	$ 47,244