8. PRODUCT WARRANTIES (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Aug. 31, 2014	Aug. 31, 2013
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance at the beginning of the period	$ 223	$ 222
Accruals for warranties issued during the period	32	92
Settlement made during the period (in cash or in kind)	(87)	(88)
Balance at the end of the period	$ 168	$ 226