INCOME TAXES (Details) - Income Tax Rate Reconciliation - USD ($)	12 Months Ended
	May 31, 2017	May 31, 2016
Income Tax Rate Reconciliation [Abstract]
Computed "expected" tax benefit	$ 317,997	$ 274,479
Increase (reduction) in income taxes resulting from:
Change in valuation allowance	(397,000)	(1,038,000)
State income taxes, net of federal benefit	30,215	34,276
Research and development tax credits	40,205	21,844
Permanent tax differences and other	8,583	3,601
Income tax (expense)		$ (703,800)