Note 8 - Stock-based Compensation - Outstanding and Exercisable Options (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Number of options outstanding, weighted average exercise price (in dollars per share)	$ 8.01	$ 5.70
Exercise Price Range 1 [Member]
Exercise price range, lower limit (in dollars per share)	4.00
Exercise price range, upper limit (in dollars per share)	$ 7.00
Number of options outstanding (in shares)	515,500
Number of options outstanding, weighted average remaining contractual term (Year)	8 years 7 months 6 days
Number of options outstanding, weighted average exercise price (in dollars per share)	$ 4.54
Number of options outstanding, intrinsic value	$ 4,514,485
Number of options exercisable (in shares)	112,375
Number of options exercisable, weighted average exercise price (in dollars per share)	$ 4.48
Number of options exercisable, intrinsic value	$ 990,989
Exercise Price Range 2 [Member]
Exercise price range, lower limit (in dollars per share)	$ 7.01
Exercise price range, upper limit (in dollars per share)	$ 10.00
Number of options outstanding (in shares)	20,000
Number of options outstanding, weighted average remaining contractual term (Year)	5 years 1 month 6 days
Number of options outstanding, weighted average exercise price (in dollars per share)	$ 8.07
Number of options outstanding, intrinsic value	$ 104,600
Number of options exercisable (in shares)	20,000
Number of options exercisable, weighted average exercise price (in dollars per share)	$ 8.07
Number of options exercisable, intrinsic value	$ 104,600
Exercise Price Range 3 [Member]
Exercise price range, lower limit (in dollars per share)	$ 10.01
Exercise price range, upper limit (in dollars per share)	$ 13.00
Number of options outstanding (in shares)	120,000
Number of options outstanding, weighted average remaining contractual term (Year)	4 years
Number of options outstanding, weighted average exercise price (in dollars per share)	$ 10.52
Number of options outstanding, intrinsic value	$ 333,800
Number of options exercisable (in shares)	120,000
Number of options exercisable, weighted average exercise price (in dollars per share)	$ 10.52
Number of options exercisable, intrinsic value	$ 333,800
Exercise Price Range 4 [Member]
Exercise price range, lower limit (in dollars per share)	$ 13.01
Exercise price range, upper limit (in dollars per share)	$ 16.00
Number of options outstanding (in shares)	244,000
Number of options outstanding, weighted average remaining contractual term (Year)	10 years
Number of options outstanding, weighted average exercise price (in dollars per share)	$ 14.11
Number of options outstanding, intrinsic value	$ 0
Number of options exercisable (in shares)	0
Number of options exercisable, weighted average exercise price (in dollars per share)	$ 0
Number of options exercisable, intrinsic value	$ 0