CONDENSED CONSOLIDATED BALANCE SHEETS (unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 28, 2019
Statement of Financial Position [Abstract]
Allowance for accounts receivable (in dollars)	$ 3,126	$ 3,838
Allowance for unbilled services (in dollars)	$ 942	$ 1,503
Preferred stock, par value (in dollars per share)	$ 0	$ 0
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value ( in dollars per share )	$ 0	$ 0
Common stock, shares authorized	25,000,000	25,000,000
Common stock, shares issued	7,739,550	7,814,797
Common stock, shares outstanding	7,739,550	7,814,797