9. CUSTOMER DEPOSITS AND DEFERRED REVENUE, SHORT-TERM (Details) - USD ($) $ in Thousands	Nov. 30, 2019	May 31, 2019
Customer Deposits And Deferred Revenue Short-term
Customer deposits	$ 1,458	$ 1,003
Deferred revenue	351	542
Total	$ 1,809	$ 1,545

Total carrying amount of consideration received or receivable as of the balance sheet date on potential earnings that were not recognized as revenue or other forms of income in conformity with GAAP, and which are expected to be recognized as such within one year or the normal operating cycle, if longer.

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.20)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_DeferredRevenueAndCreditsCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant