Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Details) - USD ($)	Nov. 30, 2020	May 31, 2020
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	$ 60,223,792	$ 60,444,330
Less: Accumulated depreciation and amortization	(27,795,521)	(26,301,923)
Net Property, Plant and Equipment	32,428,271	34,142,407
Production Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	51,262,623	51,637,883
Plant Buildings and Land [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	6,931,302	6,881,326
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	1,428,281	1,323,535
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	$ 601,586	$ 601,586