Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Sep. 28, 2013	Dec. 29, 2012
Allowance for doubtful accounts on accounts receivable	$ 84	$ 125
Common Class A
Common Stock, par value	$ 0.01	$ 0.01
Common Stock, shares authorized	22,700,000	22,700,000
Common Stock, shares issued	8,730,663	8,703,670
Common Stock, shares outstanding	8,730,663	8,703,670
Common Class B
Common Stock, par value	$ 0.01	$ 0.01
Common Stock, shares authorized	4,200,000	4,200,000
Common Stock, shares issued	4,007,355	4,107,355
Common Stock, shares outstanding	4,007,355	4,107,355