CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 30, 2013	Dec. 29, 2012	Mar. 31, 2012
CONSOLIDATED BALANCE SHEETS
Property and equipment, accumulated depreciation and amortization	$ 26,544	$ 25,123	$ 21,089
Intangible assets, accumulated amortization	$ 3,810	$ 3,810	$ 3,810
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001	$ 0.001
Common stock, shares authorized	45,000,000	45,000,000	45,000,000
Common stock, shares issued	16,435,685	16,302,007	16,154,243
Common stock, shares outstanding	16,435,685	16,302,007	16,154,243
Undesignated preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001	$ 0.001
Undesignated preferred stock, shares authorized	5,000,000	5,000,000	5,000,000
Undesignated preferred stock, shares issued	0	0	0
Undesignated preferred stock, shares outstanding	0	0	0