| Reconciliation of Federal Statutory Income Tax | 
 
 Reconciliation of the federal statutory blended income tax rate of
 28.6% for the year ended May 31, 2018 and the federal
 statutory rate of 34% for the years ended May 31, 2017 and
 May 31, 2016, to the effective income tax rate is as follows
 for all periods presented: 
 
   
 
 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  
 
 |   | 
    | 
 2018 | 
   | 
   | 
 2017 | 
   | 
   | 
 2016 | 
   | 
  
 
 | 
  
 Income tax provision at statutory rate: 
  | 
    | 
   | 
 28.6 | 
 %  | 
   | 
   | 
 34.0 | 
 %  | 
   | 
   | 
 34.0 | 
 %  | 
  
 
 | 
  
 State income taxes net 
  | 
    | 
   | 
 
 —   | 
   | 
   | 
   | 
 
 —   | 
   | 
   | 
   | 
 
 —   | 
   | 
  
 
 | 
  
 Rate Change 
  | 
    | 
   | 
 (34.8 | 
 )  | 
   | 
   | 
 
 —   | 
   | 
   | 
   | 
 
 —   | 
   | 
  
 
 | 
  
 Loss on debt conversion 
  | 
    | 
   | 
 
 —   | 
   | 
   | 
   | 
 
 —   | 
   | 
   | 
   | 
 (0.8 | 
 )  | 
  
 
 | 
  
 Derivative gain/loss 
  | 
    | 
   | 
 1.00 | 
   | 
   | 
   | 
 2.80 | 
   | 
   | 
   | 
 0.9 | 
   | 
  
 
 | 
  
 Non-deductible debt
 issuance costs 
  | 
    | 
   | 
 (0.2 | 
 )  | 
   | 
   | 
 
 —   | 
   | 
   | 
   | 
 
 —   | 
   | 
  
 
 | 
  
 Non-deductible interest on
 conversion 
  | 
    | 
   | 
 (0.1 | 
 )  | 
   | 
   | 
 
 —   | 
   | 
   | 
   | 
 
 —   | 
   | 
  
 
 | 
  
 Inducement charge 
  | 
    | 
   | 
 (2.0 | 
 )  | 
   | 
   | 
 (1.00 | 
 )  | 
   | 
   | 
 (1.0 | 
 )  | 
  
 
 | 
  
 Other 
  | 
    | 
   | 
 (1.1 | 
 )  | 
   | 
   | 
 
 —   | 
   | 
   | 
   | 
 
 —   | 
   | 
  
 
 | 
  
 Miscellaneous 
  | 
    | 
   | 
 (0.1 | 
 )  | 
   | 
   | 
 (0.10 | 
 )  | 
   | 
   | 
 (0.5 | 
 )  | 
  
 
 | 
  
 Current year credits generated 
  | 
    | 
   | 
 4.4 | 
   | 
   | 
   | 
 
 —   | 
   | 
   | 
   | 
 
 —   | 
   | 
  
 
 | 
  
 Credit carry forward generated (recorded currently) 
  | 
    | 
   | 
 4.1 | 
   | 
   | 
   | 
 
 —   | 
   | 
   | 
   | 
 
 —   | 
   | 
  
 
 | 
  
 Valuation allowance 
  | 
    | 
   | 
 0.3 | 
   | 
   | 
   | 
 (35.7 | 
 )  | 
   | 
   | 
 (32.9 | 
 )  | 
  
 
  | 
    | 
 
  
   
  | 
 
  
   
  | 
   | 
   | 
 
  
   
  | 
 
  
   
  | 
   | 
   | 
 
  
   
  | 
 
  
   
  | 
   | 
  
 
  | 
    | 
   | 
 0.0 | 
 %  | 
   | 
   | 
 0.0 | 
 %  | 
   | 
   | 
 0.0 | 
 %  | 
  
 
  | 
    | 
 
  
   
  | 
 
  
   
  | 
   | 
   | 
 
  
   
  | 
 
  
   
  | 
   | 
   | 
 
  
   
  | 
 
  
   
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   | 
  
  
  
 | 
| Net Deferred Tax Assets and Liabilities | 
 
 Net deferred tax assets and liabilities are comprised of the
 following as of May 31, 2018 and 2017: 
 
   
 
 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  
 
 |   | 
    | 
 2018 | 
   | 
    | 
 2017 | 
   | 
  
 
 | 
  
 Deferred tax asset (liability) non-current: 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
  
 
 | 
  
 Net Operating Loss 
  | 
    | 
 $ | 
 29,230,279 | 
   | 
    | 
 $ | 
 32,530,436 | 
   | 
  
 
 | 
  
 Credits 
  | 
    | 
   | 
 4,260,470 | 
   | 
    | 
   | 
 
 —   | 
   | 
  
 
 | 
  
 ASC 718 Expense on NQO’s 
  | 
    | 
   | 
 2,916,585 | 
   | 
    | 
   | 
 4,284,246 | 
   | 
  
 
 | 
  
 Charitable Contribution—Carry forward 
  | 
    | 
   | 
 
 —   | 
   | 
    | 
   | 
 25,500 | 
   | 
  
 
 | 
  
 Accrued Expenses 
  | 
    | 
   | 
 117,880 | 
   | 
    | 
   | 
 216,645 | 
   | 
  
 
 | 
  
 Fixed Assets 
  | 
    | 
   | 
 174 | 
   | 
    | 
   | 
 1,300 | 
   | 
  
 
 | 
  
 Amortization 
  | 
    | 
   | 
 139,875 | 
   | 
    | 
   | 
 186,772 | 
   | 
  
 
 | 
  
 Capitalized Debt Issuance Costs 
  | 
    | 
   | 
 
 —   | 
   | 
    | 
   | 
 157,992 | 
   | 
  
 
 | 
  
 Debt Discount 
  | 
    | 
   | 
 
 —   | 
   | 
    | 
   | 
 (31,072 | 
 )  | 
  
 
 | 
  
 Valuation allowance 
  | 
    | 
   | 
 (36,665,263 | 
 )  | 
    | 
   | 
 (37,371,817 | 
 )  | 
  
 
  | 
    | 
 
  
   
  | 
 
  
   
  | 
   | 
    | 
 
  
   
  | 
 
  
   
  | 
   | 
  
 
  | 
    | 
 $ | 
 
 —   | 
   | 
    | 
 $ | 
 
 —   | 
   | 
  
 
  | 
    | 
 
  
   
  | 
 
  
   
  | 
   | 
    | 
 
  
   
  | 
 
  
   
  | 
   | 
  
 
 | 
  
 Noncurrent asset 
  | 
    | 
 $ | 
 36,665,263 | 
   | 
    | 
 $ | 
 37,371,817 | 
   | 
  
 
 | 
  
 Valuation Allowance 
  | 
    | 
   | 
 (36,665,263 | 
 )  | 
    | 
   | 
 (37,371,817 | 
 )  | 
  
 
  | 
    | 
 
  
   
  | 
 
  
   
  | 
   | 
    | 
 
  
   
  | 
 
  
   
  | 
   | 
  
 
  | 
    | 
 $ | 
 
 —   | 
   | 
    | 
 $ | 
 
 —   | 
   | 
  
 
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