Note 11 - Share-based Compensation - Employee Stock Purchase Plan, Valuation Assumptions (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Dividend yield	0.00%	0.00%
Expected life in years (Year)	10 years	10 years
Employee Stock Purchase Plan [Member]
Dividend yield	0.00%	0.00%
Expected life in years (Year)	3 months	3 months
Minimum [Member]
Risk-free interest rate	1.63%	0.93%
Expected volatility	54.44%	54.61%
Minimum [Member] | Employee Stock Purchase Plan [Member]
Risk-free interest rate	0.52%	0.03%
Expected volatility	43.11%	49.27%
Maximum [Member]
Risk-free interest rate	3.67%	1.69%
Expected volatility	55.41%	55.39%
Maximum [Member] | Employee Stock Purchase Plan [Member]
Risk-free interest rate	4.42%	0.06%
Expected volatility	87.26%	70.32%