Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Unrecognized cost of unvested share-based compensation awards.

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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Number of additional shares authorized for issuance under an established share-based compensation plan.

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The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

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Gross number of share options (or share units) granted during the period.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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Number of options outstanding, including both vested and non-vested options.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Number of share options (or share units) exercised during the current period.

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Note 3 - Stock-based Compensation and Shareholders' Equity (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Allocated Share-based Compensation Expense	$ 36	$ 33	$ 58	$ 51
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$ 161		$ 161
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition			32 months
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross			25,000	25,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period			10,000	10,675
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	98,925	88,175	98,925	88,175	85,525	73,950
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value			$ 5.29	$ 3.88
The 2005 Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized			200,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross			184,200
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period			65,850
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period			91,825
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	26,525		26,525
The 2015 Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross			73,500
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period			1,100
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period			0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	73,500		73,500
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in Shares)	300,000		300,000
Employee Stock Option [Member] \| The 2005 Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period			3 years
Employee Stock Option [Member] \| Minimum [Member] \| The 2005 Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period			6 months
Employee Stock Option [Member] \| Maximum [Member] \| The 2005 Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period			5 years