Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Statements of Cash Flows [Abstract]
Cash and cash equivalents	$ 2,791	$ 6,892
Restricted cash included in fixed short-term bank deposits	1,325	1,197
Restricted cash included in fixed short-term bank deposits	9	990
Cash, cash equivalents and restricted cash	$ 4,125	$ 9,079

Amount of cash and cash equivalents restricted as to withdrawal or usage. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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