Note 7 - Stockholders' Equity - Warrants (Details)	6 Months Ended
	Jun. 30, 2023 $ / shares shares
Balance , number of common stock warrants (in shares) | shares	2,424,724
Balance, weighted average exercise price (in dollars per share) | $ / shares	$ 6.36
Warrants for common stock sold , number of common stock warrants (in shares) | shares	0
Warrants for common stock sold, weighted average exercise price (in dollars per share) | $ / shares	$ 0
Warrants for common stock exercised , number of common stock warrants (in shares) | shares	0
Warrants for common stock exercised, weighted average exercise price (in dollars per share) | $ / shares	$ 0
Balance , number of common stock warrants (in shares) | shares	2,424,724
Balance as, weighted average exercise price (in dollars per share) | $ / shares	$ 6.36