11. STOCKHOLDERS’ EQUITY, COMPREHENSIVE INCOME AND STOCK-BASED COMPENSATION (Details) $ in Thousands	3 Months Ended
	Aug. 31, 2018 USD ($)
Accumulated other comprehensive income, beginning	$ 2,292	[1]
Other comprehensive (loss) income before reclassifications	(16)
Amounts reclassified out of AOCI	0
Other comprehensive income (loss), net of tax	(16)
Accumulated other comprehensive income, ending	2,276
Cumulative Translation Adjustments [Member]
Accumulated other comprehensive income, beginning	2,292
Other comprehensive (loss) income before reclassifications	(16)
Amounts reclassified out of AOCI	0
Other comprehensive income (loss), net of tax	(16)
Accumulated other comprehensive income, ending	2,276
Unrealized loss on Investments, Net
Accumulated other comprehensive income, beginning	0
Other comprehensive (loss) income before reclassifications	0
Amounts reclassified out of AOCI	0
Other comprehensive income (loss), net of tax	0
Accumulated other comprehensive income, ending	$ 0

[1] The condensed consolidated balance sheet at May 31, 2018 has been derived from the audited consolidated financial statements at that date.