XML 51 R39.htm IDEA: XBRL DOCUMENT v3.8.0.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Concentration risks, Revenue recognition, Litigation proceeds & Income taxes(Details)
 12 Months Ended
Jan. 01, 2018
Dec. 31, 2017
USD ($)
item
Dec. 31, 2016
USD ($)
item
Dec. 31, 2015
USD ($)
item
Concentration risks        
Number of significant customers | item   2 1 2
Aggregate dollar amount of net sales to significant customers   $ 34,493,838 $ 29,826,636 $ 29,552,200
Revenue recognition        
Estimated contractual allowance   $ 4,115,628 $ 3,591,534  
Period for return of incorrect shipments   10 days    
Number of times overstocking returns are limited | item   2    
Period for return of product due to overstock   12 months    
Maximum percentage of distributor's total purchase for the prior 12-month period   1.00%    
Income taxes        
Income tax at the federal statutory rate (as a percent)   35.00% 35.00% 35.00%
Customer Concentration Risk        
Concentration risks        
Decrease in allowance for doubtful accounts     $ 1,600,000  
Forecast        
Income taxes        
Income tax at the federal statutory rate (as a percent) 21.00%      
Sales | Customer Concentration Risk        
Concentration risks        
Aggregate dollar amount of net sales to significant customers   $ 14,000,000 $ 9,400,000 $ 13,500,000
Percentage of net sales to significant customers (as a percent)   40.50% 31.40% 45.70%
Cost of Goods, Product Line | Supplier Concentration Risk        
Concentration risks        
Percentage of net sales to significant customers (as a percent)   90.40% 86.30% 77.70%