Note 9 - Share-based Compensation - Fair Value Assumptions (Details) - $ / shares	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-Based Payment Arrangement, Option [Member]
Expected volatility	105.00%
Expected dividend yield	0.00%	0.00%	0.00%
Contractual life (years) (Year)	10 years		10 years
Share-Based Payment Arrangement, Option [Member] \| SEED 2022 Share Incentive Plan [Member]
Expected dividend yield	0.00%	0.00%
Contractual life (years) (Year)	10 years	10 years
Share-Based Payment Arrangement, Option [Member] \| Minimum [Member]
Fair value of ordinary share (in dollars per share)	$ 0.77	$ 1.14	$ 9.48
Risk-free interest rate	3.47%	1.23%	0.37%
Expected term (years) (Year)	5 years 25 days	3 years 18 days	5 years
Expected volatility		100.00%	75.00%
Contractual life (years) (Year)		5 years
Share-Based Payment Arrangement, Option [Member] \| Minimum [Member] \| SEED 2022 Share Incentive Plan [Member]
Fair value of ordinary share (in dollars per share)	$ 0.19	$ 0.44
Risk-free interest rate	3.47%	2.54%
Expected term (years) (Year)	5 years 14 days	5 years 3 months
Expected volatility	105.97%	99.34%
Share-Based Payment Arrangement, Option [Member] \| Maximum [Member]
Fair value of ordinary share (in dollars per share)	$ 1.75	$ 3.48	$ 31.31
Risk-free interest rate	4.29%	3.16%	1.47%
Expected term (years) (Year)	6 years	6 years	7 years 5 months 26 days
Expected volatility		115.00%	90.00%
Contractual life (years) (Year)		10 years
Share-Based Payment Arrangement, Option [Member] \| Maximum [Member] \| SEED 2022 Share Incentive Plan [Member]
Fair value of ordinary share (in dollars per share)	$ 0.44	$ 0.5
Risk-free interest rate	4.73%	3.75%
Expected term (years) (Year)	6 years 6 months	6 years 6 months
Expected volatility	141.40%	106.73%
Options Granted in May 2021 [Member]
Fair value of ordinary share (in dollars per share)	$ 10.71
Risk-free interest rate	1.63%
Expected term (years) (Year)	10 years
Expected volatility	75.00%
Expected dividend yield	0.00%
Exercise price (in dollars per share)	$ 10.18

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

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(iii)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

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- Definition

The estimated measure of the 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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(ii)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(iv)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

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- Definition

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

+ References

No definition available.

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

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- Definition

Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

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