Debt - Schedule of Long-Term Debt (Details) - USD ($)	Aug. 31, 2018	May 31, 2018
Face value of long-term debt	$ 20,253,267	$ 19,251,596
Debt issue costs, net of amortization	(59,106)	(91,370)
Total debt, net of debt issue costs	20,194,161	19,160,226
Less: Current Portion	(2,511,874)	(2,324,046)
Long-term debt	17,682,287	16,836,180
Term Loan A Payable to International Bank of Commerce, Prime Rate of Interest Plus 0.5% But Not Less Than 4.0%, Maturing April 30, 2023 [Member]
Face value of long-term debt	3,774,793	3,945,443
Term Loan C Payable to International Bank of Commerce, Prime Rate of Interest Plus 0.5% but Not Less Than 4.0%, Maturing August 4, 2020 [Member]
Face value of long-term debt	1,560,092	1,613,445
Term Loan D Payable to International Bank of Commerce, Prime Rate of Interest Plus 0.5% but Not Less Than 4.75%, Maturing January 10, 2022 [Member]
Face value of long-term debt	2,173,836	2,314,935
Term Loan E Payable to International Bank of Commerce, Prime Rate of Interest Plus 0.5% but Not Less Than 4.75%, Maturing January 10, 2022 [Member]
Face value of long-term debt	1,000,000	843,200
Term Loan F Payable to International Bank of Commerce, Prime Rate of Interest Plus 0.5% but Not Less Than 5.25%, Maturing February 8, 2021 [Member]
Face value of long-term debt	1,700,000
Revolving Loan Payable to International Bank of Commerce, Prime Rate of Interest Plus 0.5% But Not Less Than 4.75%, Due January 31, 2020 [Member]
Face value of long-term debt	1,579,000	1,879,000
Note Payable to First Bank, Prime Rate of Interest Plus 1.45% but Not Less Than 4.95%, Monthly Principal and Interest Payment of $30,628, Due August 21, 2021, Secured by Production Equipment [Member]
Face value of long-term debt	1,029,668	1,099,447
Term Loan Payable by Gre to International Bank of Commerce, Interest Rate of 5.5%, Monthly Principal and Interest Payment of $26,215, Due April 30, 2023 [Member]
Face value of long-term debt	2,604,879	2,652,428
Note Payable to Robert Rosene, 7.5% Interest, Due January 15, 2020 [Member]
Face value of long-term debt	4,467,330	4,469,355
Note Payable to Yorktown Management & Financial Services, LLC, 5.0% Interest, Due February 28, 2019, Monthly Principal and Interest Payments of $20,629 [Member]
Face value of long-term debt	121,988	181,850
Other Note Payable [Member]
Face value of long-term debt	$ 241,681	$ 252,493

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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