CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 29, 2019	Dec. 30, 2018
Trade receivables, allowance	$ 1,447	$ 3,008
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Treasury stock, shares	59,893	252
Common Class A
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	5,561,493	5,384,303
Common Class B
Common stock, shares authorized	60,000,000	60,000,000
Common stock, shares issued	2,428,191	2,428,191