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Note 10 - Share-based Compensation - Options Activities (Details) - The 2017 Omnibus Incentive Plan [Member] - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	May 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Outstanding, number of options (in shares)		1,939,049	149,700	465,900
Outstanding, weighted average exercise price (in dollars per share)		$ 14.12	$ 23.61	$ 27.91
Outstanding, weighted average remaining contractual term (Year)		8 years 9 months 25 days	9 years 4 months 17 days	8 years 8 months 8 days	9 years 1 month 13 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value		$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)	370,000	1,134,672	1,791,943	19,700
Granted, weighted average exercise price (in dollars per share)		$ 11.24	$ 13.32	$ 13.96
Granted, weighted average grant date fair value (in dollars per share)		$ 8.19	$ 8.21	$ 8.63
Canceled, number of options (in shares)				(335,900)
Canceled, weighted average exercise price (in dollars per share)				$ 29.00
Canceled, weighted average grant date fair value (in dollars per share)				$ 19.91
Forfeited, number of options (in shares)		(307,883)	(2,594)
Forfeited, weighted average exercise price (in dollars per share)		$ 14.52	$ 13.83
Forfeited, weighted average grant date fair value (in dollars per share)		$ 9.06	$ 8.64
Exercised, number of options (in shares)		(98,500)
Exercised, weighted average exercise price (in dollars per share)		$ 16.13
Exercised, weighted average grant date fair value (in dollars per share)		$ 9.66
Exercised, average intrinsic value		$ 473	$ 0
Outstanding, number of options (in shares)		2,667,338	1,939,049	149,700	465,900
Outstanding, weighted average exercise price (in dollars per share)		$ 12.77	$ 14.12	$ 23.61	$ 27.91
Exercisable, number of options (in shares)		871,881
Exercisable, weighted average exercise price (in dollars per share)		$ 14.58
Exercisable, weighted average remaining contractual term (Year)		8 years 4 months 28 days
Vested and expected to vest, number of options (in shares)		1,777,271
Vested and expected to vest, weighted average exercise price (in dollars per share)		$ 13.51
Vested and expected to vest, weighted average remaining contractual term (Year)		8 years 8 months 23 days
Vested and expected to vest, average intrinsic value			$ 0

X

- Definition

The weighted average grant date fair value of options exercised in period under share based payment arrangement.

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

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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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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Amount by which current fair value of underlying stock exceeds exercise price of fully vested and expected to vest options outstanding. 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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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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Weighted-average exercise price, at which grantee can acquire shares reserved for issuance, for fully vested and expected to vest options outstanding. 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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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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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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