ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details 1) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Contract assets:
Unbilled receivables	$ 3,425	$ 4,850
Contract liabilities:
Customer advances and unearned income	3,766	3,372
Unearned event income	$ 3,864	$ 4,117

Amount received for services rendered and products shipped, but not yet billed, for non-contractual agreements due within one year or the normal operating cycle, if longer.

No definition available.

Name:	us-gaap_UnbilledReceivablesCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant