Debt - Schedule of Debt (Details) - USD ($)	Nov. 30, 2017	May 31, 2017
Total debt	$ 18,762,018	$ 18,032,416
Debt issue costs, net of amortization	(164,219)	(228,426)
Less: Current portion	(2,794,286)	(2,493,236)
Long-term Debt	15,803,513	15,310,754
Term Loan A Payable to International Bank of Commerce, Prime Rate of Interest Plus 0.5% but Not Less Than 4.0%, Maturing January 7, 2019 [Member]
Total debt	4,287,282	4,626,191
Term Loan B Payable to International Bank of Commerce, Prime Rate of Interest Plus 0.5% but Not Less Than 4.0%, Maturing January 7, 2019 [Member]
Total debt	1,215,061	1,715,132
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]
Total debt	1,721,667
Revolving Loan Payable to International Bank of Commerce, Prime Rate of Interest Plus 0.5% but Not Less Than 4.0%, Due January 31, 2019 [Member]
Total debt	2,500,000	2,260,000
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]
Total debt	1,248,240	1,396,448
Term Loan Payable by Gre to International Bank of Commerce, Interest Rate of 4.5%, Monthly Principal and Interest Payments of $26,215, Due January 31, 2019 [Member]
Total debt	2,748,105	2,841,285
Note Payable to Robert Rosene, 7.5% Interest, Due January 15, 2019 [Member]
Total debt	4,469,355	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]
Total debt	299,358	413,969
Other Note Payable [Member]
Total debt	$ 272,950	$ 310,036