CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, unless otherwise specified	Dec. 29, 2012	Mar. 31, 2012
Trade receivables, allowances	$ 452	$ 390
Property, plant and equipment, accumulated depreciation	106,815	101,716
Acquired intangible assets, accumulated amortization	$ 12,422	$ 10,609
Preferred stock, without par value
Preferred stock, shares authorized	1,000	1,000
Preferred stock, shares issued
Common stock, without par value
Common stock, shares authorized	100,000	100,000
Common stock, issued	29,497	28,970
Common stock, outstanding	29,497	28,970