Commitments and Contingencies (Details Textual)	12 Months Ended
	May 31, 2017 USD ($) Officers	May 31, 2016 USD ($)
Commitments and Contingencies (Textual)
Rent expenses under all lease agreements	$ 372,000	$ 379,000
Employment Agreement [Member]
Commitments and Contingencies (Textual)
Number of officers | Officers	2
Description of agreement expiration date	2020 and 2022
Payment due under agreement	$ 2,500,000