Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Apr. 01, 2017	Dec. 31, 2016
Allowance for doubtful accounts on accounts receivable	$ 4	$ 0
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	9,245,882	9,170,956
Common Stock, shares outstanding	9,245,882	9,170,956
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	3,097,355	3,197,355
Common Stock, shares outstanding	3,097,355	3,197,355