SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Income Taxes and Recent Accounting Pronouncements (Details) - USD ($)
12 Months Ended
Dec. 30, 2016
Jan. 02, 2015
Jan. 01, 2016
Income Taxes      
Valuation reserve related to California net operating losses $ 72,000   $ 73,000
Reversal of valuation allowance   $ 4,600,000  
Early adoption effect | ASU 2016-09      
Income Taxes      
Decrease to tax expense $ 194,000