Consolidated Balance Sheets (Parenthetical) - USD ($)	Dec. 27, 2020	Dec. 29, 2019
Statement of Financial Position [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 739,000	$ 595,000
Notes receivable, allowance	103,000	37,000
Notes receivable - noncurrent, allowance for doubtful accounts	271,000	112,000
Dividends payable to related parties, current	0	149,000
Dividends payable to related parties, noncurrent	$ 0	$ 99,000
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	1,183,272	0
Preferred stock, shares outstanding	1,183,272	0
Preferred stock, liquidation preference	$ 25	$ 0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	25,000,000	25,000,000
Common stock, shares issued	11,926,264	11,860,299
Common stock, shares outstanding	11,926,264	11,860,299