Condensed Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 29, 2019	Dec. 29, 2018
Statement of Financial Position [Abstract]
Allowance for doubtful accounts and sales promotions on accounts receivable	$ 521	$ 491
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	100,000	100,000
Preferred stock, shares issued
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	15,000,000	15,000,000
Common stock, shares issued	5,153,706	5,153,706
Common stock, shares outstanding	5,153,706	5,153,706