Note 11 - Stockholders' Equity - Stock by Class (Details) - $ / shares	Dec. 31, 2022	Dec. 31, 2021
Common stock shares authorized (in shares)	125,000,000	125,000,000
Common Stock, Par or Stated Value Per Share (in dollars per share)	$ 0.001	$ 0.001
Common stock shares issued (in shares)	50,554,179	41,307,617
Preferred stock shares authorized (in shares)	3,000,000	3,000,000
Preferred stock par value (in dollars per share)	$ 0	$ 0
Preferred stock shares issued (in shares)	0	0