Note 15 - Share-based Compensation - Fair Value of Options Granted Valuation Assumption (Details) - Share-based Payment Arrangement, Option [Member] - $ / shares	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Dividend yield	0.00%	0.00%
Expected volatility, minimum	73.76%	71.43%
Expected volatility, maximum	79.16%	79.80%
Risk-free interest rate, minimum	0.60%	0.37%
Risk-free interest rate, maximum	1.62%	1.35%
Minimum [Member]
Value of ordinary shares (in dollars per share)	$ 11.92	$ 16.50
Maximum [Member]
Value of ordinary shares (in dollars per share)	$ 22.07	$ 29.41

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(iii)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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The estimated measure of the maximum percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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The estimated measure of the minimum percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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The maximum risk-free interest rate assumption that is used in valuing an option on its own shares.

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The minimum risk-free interest rate assumption that is used in valuing an option on its own shares.

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- Definition

Price of a single share of a number of saleable stocks of a company.

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