Fair value of non-vested equity-based payment instruments, excluding stock (or unit) options, vested.

No definition available.

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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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Aggregate number of common shares reserved for future issuance.

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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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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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Agreed-upon price for the exchange of the underlying asset relating to the share-based payment award.

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No definition available.

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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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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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- Definition

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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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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

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Number of fully vested and expected to vest options outstanding that can be converted into shares under option plan. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Percentage of vesting of share-based compensation awards.

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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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Note 7 - Stock-based Compensation (Details Textual) - USD ($)		12 Months Ended
	Feb. 27, 2018	Dec. 31, 2018	Dec. 31, 2017	May 31, 2017	Dec. 31, 2016	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number, Ending Balance		279,919	237,926		98,439
Allocated Share-based Compensation Expense, Total		$ 1,519,000	$ 1,270,000
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance		964,997	999,997		999,997
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		35,000
Restricted Stock [Member]
Allocated Share-based Compensation Expense, Total		$ 413,000	$ 149,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Total		$ 1,100,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition		3 years
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Fair Value		$ 1,300,000	365,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value		$ 1,100,000	$ 154,000
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance		2,043,402	2,390,012		2,513,861
Allocated Share-based Compensation Expense, Total		$ 597,000	$ 612,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value		$ 0	$ 1.91
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		330,983	131,427
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value		$ 3,800,000	$ 91,817
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value		20,700,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value		$ 16,900,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term		5 years 146 days
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Total		$ 531,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition		1 year 182 days
The 2013 Performance Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance		2,600,000
The 2013 Performance Incentive Plan [Member] \| Performance Shares [Member]
Common Stock, Capital Shares Reserved for Future Issuance				4,100,000		3,100,000
The 2013 Performance Incentive Plan [Member] \| Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number, Ending Balance		280,000
All Other Unapproved Compensation Plans [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance		425,000
Management Performance Bonus Plan 2017 [Member] \| Performance Shares [Member]
Allocated Share-based Compensation Expense, Total		$ 509,000	$ 509,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		35,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value		$ 285,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value		10,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value		$ 4,800,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term		3 years
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized			1,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Exercise Price			$ 1.64
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number	999,997
Management Performance Bonus Plan 2017 [Member] \| Performance Shares [Member] \| Vesting on Release of Audited Financial Statements for 2017 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage			50.00%
Management Performance Bonus Plan 2017 [Member] \| Performance Shares [Member] \| Vesting One Year After Release of Audited Financial Statements for 2017 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage			50.00%
Management Performance Bonus Plan 2017 [Member] \| Performance Shares [Member] \| Share-based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	50.00%
Management Performance Bonus Plan 2017 [Member] \| Performance Shares [Member] \| Share-based Compensation Award, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	50.00%