COMMITMENTS - Benefit Plans (Details) - USD ($)
12 Months Ended
Dec. 30, 2016
Jan. 01, 2016
Jan. 02, 2015
Employee Benefit Plans      
Maximum employee contribution as a percentage of compensation under 401 (k) Plan 50.00%    
Matching contributions by the company under 401(k) Plan $ 900,000 $ 777,000 $ 624,000
Bonus expense under discretionary bonus plan 2,709,000 1,268,000 $ 1,500,000
Bonus expense included in accrued liabilities as of the balance sheet date 2,090,000 922,000  
Post employment health benefits      
Unamortized compensation cost 0    
Present value of expected payments for health insurance coverage $ 110,000 $ 126,000