Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 26, 2015	Dec. 27, 2014
Allowance for doubtful accounts on accounts receivable	$ 91	$ 144
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	9,514,599	9,452,375
Common Stock, shares outstanding	9,514,599	9,452,375
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	3,467,355	3,617,355
Common Stock, shares outstanding	3,467,355	3,617,355