Note 12 - Summary of Stock Options - Summary of Options Outstanding and Exercisable (Details)	9 Months Ended
	Sep. 30, 2022 $ / shares shares
Options outstanding, number (in shares) | shares	4,105,706
Options outstanding, weighted average exercise price (in dollars per share)	$ 6.05
Options outstanding, weighted average remaining contractual term (Year)	8 years 6 months
$0.66Options exercisable, number exercisable (in shares) | shares	1,521,946
Options exercisable, weighted average exercise price (in dollars per share)	$ 11.45
Range One [Member]
Exercise price range, lower limit (in dollars per share)	0
Exercise price range, upper limit (in dollars per share)	$ 1.26
Options outstanding, number (in shares) | shares	953,167
Options outstanding, weighted average exercise price (in dollars per share)	$ 1.25
Options outstanding, weighted average remaining contractual term (Year)	9 years 3 months 18 days
$0.66Options exercisable, number exercisable (in shares) | shares	157,712
Options exercisable, weighted average exercise price (in dollars per share)	$ 1.26
Range Two [Member]
Exercise price range, lower limit (in dollars per share)	2.28
Exercise price range, upper limit (in dollars per share)	$ 2.96
Options outstanding, number (in shares) | shares	2,196,021
Options outstanding, weighted average exercise price (in dollars per share)	$ 2.73
Options outstanding, weighted average remaining contractual term (Year)	8 years 8 months 12 days
$0.66Options exercisable, number exercisable (in shares) | shares	688,362
Options exercisable, weighted average exercise price (in dollars per share)	$ 2.73
Range Three [Member]
Exercise price range, lower limit (in dollars per share)	3.06
Exercise price range, upper limit (in dollars per share)	$ 3.40
Options outstanding, number (in shares) | shares	10,000
Options outstanding, weighted average exercise price (in dollars per share)	$ 3.20
Options outstanding, weighted average remaining contractual term (Year)	8 years 6 months
$0.66Options exercisable, number exercisable (in shares) | shares	3,771
Options exercisable, weighted average exercise price (in dollars per share)	$ 3.20
Range Four [Member]
Exercise price range, lower limit (in dollars per share)	4.45
Exercise price range, upper limit (in dollars per share)	$ 4.80
Options outstanding, number (in shares) | shares	11,900
Options outstanding, weighted average exercise price (in dollars per share)	$ 4.72
Options outstanding, weighted average remaining contractual term (Year)	8 years 2 months 12 days
$0.66Options exercisable, number exercisable (in shares) | shares	5,319
Options exercisable, weighted average exercise price (in dollars per share)	$ 4.71
Range Five [Member]
Exercise price range, lower limit (in dollars per share)	5.10
Exercise price range, upper limit (in dollars per share)	$ 5.40
Options outstanding, number (in shares) | shares	88,000
Options outstanding, weighted average exercise price (in dollars per share)	$ 5.28
Options outstanding, weighted average remaining contractual term (Year)	8 years
$0.66Options exercisable, number exercisable (in shares) | shares	63,250
Options exercisable, weighted average exercise price (in dollars per share)	$ 5.34
Range Six [Member]
Exercise price range, lower limit (in dollars per share)	6.90
Exercise price range, upper limit (in dollars per share)	$ 6.90
Options outstanding, number (in shares) | shares	5,400
Options outstanding, weighted average exercise price (in dollars per share)	$ 6.90
Options outstanding, weighted average remaining contractual term (Year)	7 years 6 months
$0.66Options exercisable, number exercisable (in shares) | shares	3,376
Options exercisable, weighted average exercise price (in dollars per share)	$ 6.90
Range Seven [Member]
Exercise price range, lower limit (in dollars per share)	8.60
Exercise price range, upper limit (in dollars per share)	$ 8.91
Options outstanding, number (in shares) | shares	822,332
Options outstanding, weighted average exercise price (in dollars per share)	$ 8.69
Options outstanding, weighted average remaining contractual term (Year)	7 years 1 month 6 days
$0.66Options exercisable, number exercisable (in shares) | shares	583,220
Options exercisable, weighted average exercise price (in dollars per share)	$ 8.69
Range Eight [Member]
Exercise price range, lower limit (in dollars per share)	10.90
Exercise price range, upper limit (in dollars per share)	$ 13.60
Options outstanding, number (in shares) | shares	15,500
Options outstanding, weighted average exercise price (in dollars per share)	$ 12.64
Options outstanding, weighted average remaining contractual term (Year)	7 years 4 months 24 days
$0.66Options exercisable, number exercisable (in shares) | shares	13,553
Options exercisable, weighted average exercise price (in dollars per share)	$ 12.89
Range Nine [Member]
Exercise price range, lower limit (in dollars per share)	380.00
Exercise price range, upper limit (in dollars per share)	$ 9,920.00
Options outstanding, number (in shares) | shares	3,386
Options outstanding, weighted average exercise price (in dollars per share)	$ 2,869.31
Options outstanding, weighted average remaining contractual term (Year)	5 years 6 months
$0.66Options exercisable, number exercisable (in shares) | shares	3,383
Options exercisable, weighted average exercise price (in dollars per share)	$ 2,870.91