7. INCOME TAXES (Details Narrative) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2018	May 31, 2017	May 31, 2016	May 31, 2015
Valuation allowance	$ (6,139)	$ 1,635	$ 421
Foreign net operating loss carryforwards	457
Unrecognized tax benefits	1,785	$ 789	$ 789	$ 919
Federal refundable AMT credit	90
Reduction in deferred tax assets	(6,400)
Federal
Net operating loss carryforward	50,356
Research and development tax credit carryforwards	2,157
State
Net operating loss carryforward	31,340
Research and development tax credit carryforwards	5,248
Alternative minimum tax credit carryforwards	$ 34