REVOLVING BANK LOAN (Details)		12 Months Ended
	May 26, 2017 USD ($)	Dec. 30, 2017 USD ($) agreement	Dec. 31, 2016 USD ($)
REVOLVING BANK LOAN AND LONG-TERM DEBT
Number of separate amendments to the Credit agreement | agreement		7
Period over which existing cash balance, anticipated cash flow from operations and borrowings available under the credit agreement will be sufficient to cover expected cash needs		12 months
Invested and capitalized		$ 5,430,000
Revolving Credit Facility
REVOLVING BANK LOAN AND LONG-TERM DEBT
Maximum revolving credit facility line	$ 20,000,000
Maximum borrowings as a percentage of eligible accounts receivable	80.00%
Borrowings as a percentage of eligible inventories	50.00%
Amount available to borrow in calculation if less than 50% of eligible inventories	$ 8,500,000
Borrowings as a percentage of new qualifying Capital Expenditures with restrictions	80.00%
Annual new qualifying capital expenditures for fiscal year 2016, maximum	$ 5,500,000
Annual new qualifying capital expenditures for fiscal year 2017, maximum	5,500,000
Minimum tangible net worth threshold, base amount	$ 31,000,000	33,752,000
Minimum tangible net worth threshold, percentage of the consolidated net income	50.00%
Maximum balance sheet leverage ratio	1.00
Outstanding amount		3,500,000	$ 2,000,000
Highest balance outstanding during the period		10,000,000	7,500,000
Average outstanding		5,909,000	$ 3,712,000
Outstanding amount of letters of credit total		6,205,000
Revolving Credit Facility | Minimum [Member]
REVOLVING BANK LOAN AND LONG-TERM DEBT
Fixed charge coverage ratio	1.15
Revolving Credit Facility | Debt Instrument Variable Rate Base London Inter Bank offered Rate [Member]
REVOLVING BANK LOAN AND LONG-TERM DEBT
Variable interest rate base	LIBOR
Percentage points added to the reference rate	2.25%
Revolving Credit Facility | Debt Instrument Variable Rate Base Prime [Member]
REVOLVING BANK LOAN AND LONG-TERM DEBT
Variable interest rate base	prime rate.
Second Letter of Credit
REVOLVING BANK LOAN AND LONG-TERM DEBT
Outstanding amount of letters of credit total		$ 1,250,000