Note 7 - Share-based Compensation - Stock Option Activity (Details) $ / shares in Units, $ in Thousands	9 Months Ended
Sep. 30, 2019 USD ($) $ / shares shares
Balance, shares (in shares) \| shares	24,000
Balance, weighted average exercise price (in dollars per share) \| $ / shares	$ 24.15
Options granted, shares (in shares) \| shares
Options granted, weighted average exercise price (in dollars per share) \| $ / shares
Options exercised, shares (in shares) \| shares
Options exercised, weighted average exercise price (in dollars per share) \| $ / shares
Options canceled, shares (in shares) \| shares
Options canceled, weighted average exercise price (in dollars per share) \| $ / shares
Balance, shares (in shares) \| shares	24,000
Balance, weighted average exercise price (in dollars per share) \| $ / shares	$ 24.15
Exercisable, shares (in shares) \| shares	24,000
Exercisable, weighted average exercise price (in dollars per share) \| $ / shares	$ 24.15
Exercisable, weighted average remaining contractual life (Year)	182 days
Exercisable, aggregate instrinsic value \| $	$ 96

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

+ References

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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.

+ References

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Weighted average price of options that were either forfeited or expired.

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

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No definition available.

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

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, 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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-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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Note 7 - Share-based Compensation - Stock Option Activity (Details) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2019 USD ($) $ / shares shares
Balance, shares (in shares) \| shares	24,000
Balance, weighted average exercise price (in dollars per share) \| $ / shares	$ 24.15
Options granted, shares (in shares) \| shares
Options granted, weighted average exercise price (in dollars per share) \| $ / shares
Options exercised, shares (in shares) \| shares
Options exercised, weighted average exercise price (in dollars per share) \| $ / shares
Options canceled, shares (in shares) \| shares
Options canceled, weighted average exercise price (in dollars per share) \| $ / shares
Balance, shares (in shares) \| shares	24,000
Balance, weighted average exercise price (in dollars per share) \| $ / shares	$ 24.15
Exercisable, shares (in shares) \| shares	24,000
Exercisable, weighted average exercise price (in dollars per share) \| $ / shares	$ 24.15
Exercisable, weighted average remaining contractual life (Year)	182 days
Exercisable, aggregate instrinsic value \| $	$ 96