Note 10 - Equity Incentive Plans - Assumptions of Options (Details) - Share-Based Payment Arrangement, Option [Member]	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Minimum [Member]
Risk-free interest rate	3.70%	3.50%
Expected term (in years) (Year)		5 years 6 months
Expected volatility	128.90%	127.80%
Maximum [Member]
Risk-free interest rate	4.40%	4.20%
Expected term (in years) (Year)		6 years
Expected volatility	130.80%	133.80%