10. ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) $ in Thousands	9 Months Ended
	Feb. 28, 2018 USD ($)
Accumulated other comprehensive income, beginning	$ 2,249	[1]
Other comprehensive income (loss) before reclassifications	95
Other comprehensive income (loss), net of tax	95
Accumulated other comprehensive income, ending	2,344
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Accumulated other comprehensive income, beginning	2,249
Other comprehensive income (loss) before reclassifications	98
Other comprehensive income (loss), net of tax	98
Accumulated other comprehensive income, ending	2,347
Unrealized loss on Investments, Net
Accumulated other comprehensive income, beginning	0
Other comprehensive income (loss) before reclassifications	(3)
Other comprehensive income (loss), net of tax	(3)
Accumulated other comprehensive income, ending	$ (3)

[1] The condensed consolidated balance sheet at May 31, 2017 has been derived from the audited consolidated financial statements at that date.