Note 8 - Stock-based Compensation - Stock Option Plan (Details)	3 Months Ended
	Mar. 31, 2023 $ / shares shares
Outstanding at January 1, 2023 (in shares) | shares	673,000
Outstanding, weighted average exercise price (in dollars per share) | $ / shares	$ 5.70
Granted (in shares) | shares	244,000
Granted, weighted average exercise price (in dollars per share) | $ / shares	$ 14.11
Exercised (in shares) | shares	(17,500)
Exercised, weighted average exercise price (in dollars per share) | $ / shares	$ 4.19
Outstanding at March 31, 2023 (in shares) | shares	899,500
Outstanding, weighted average exercise price (in dollars per share) | $ / shares	$ 8.01