Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 29, 2019	Dec. 30, 2018
Statement Of Financial Position [Abstract]
Property and equipment, at cost, less accumulated depreciation and amortization	$ 62,159	$ 53,821
Deferred charges, accumulated amortization	$ 327	$ 285
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	30,000,000	30,000,000
Common stock, shares issued	14,959,176	14,695,176
Common stock, shares outstanding	14,959,176	14,695,176
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0