Supplementary Financial Statements Information (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Other accounts receivable:
Prepaid expenses	$ 164	$ 751
Government departments and agencies	129	277
Others	46	64
Other accounts receivable	$ 339	$ 1,092

Amount of asset related to consideration paid in advance for income and other taxes that provide economic benefits within a future period of one year or the normal operating cycle, if longer.

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