Note 12 - Share-based Compensation - Information Regarding Stock Options Outstanding (Details)	12 Months Ended
	Dec. 31, 2022 $ / shares shares
Exercise Price Range One [Member]
Share-Based Payment Arrangement, Option, Exercise Price Range, Lower Range Limit (in dollars per share)	$ 1.50
Share-Based Payment Arrangement, Option, Exercise Price Range, Upper Range Limit (in dollars per share)	$ 2.27
Number outstanding (in shares) | shares	820,750
Options outstanding, weighted average remaining contractual term (Year)	4 months 20 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 1.62
Options exercisable, number of shares (in shares) | shares	481,750
Options exercisable, weighted average exercise price (in dollars per share)	$ 1.50
Exercise Price Range Two [Member]
Share-Based Payment Arrangement, Option, Exercise Price Range, Lower Range Limit (in dollars per share)	2.55
Share-Based Payment Arrangement, Option, Exercise Price Range, Upper Range Limit (in dollars per share)	$ 3.83
Number outstanding (in shares) | shares	876,409
Options outstanding, weighted average remaining contractual term (Year)	10 months 13 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 2.92
Options exercisable, number of shares (in shares) | shares	35,000
Options exercisable, weighted average exercise price (in dollars per share)	$ 3.61
Exercise Price Range Three [Member]
Share-Based Payment Arrangement, Option, Exercise Price Range, Lower Range Limit (in dollars per share)	3.85
Share-Based Payment Arrangement, Option, Exercise Price Range, Upper Range Limit (in dollars per share)	$ 5.78
Number outstanding (in shares) | shares	2,050,010
Options outstanding, weighted average remaining contractual term (Year)	2 years 2 months 8 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 5.24
Options exercisable, number of shares (in shares) | shares	1,869,613
Options exercisable, weighted average exercise price (in dollars per share)	$ 5.28
Exercise Price Range Four [Member]
Share-Based Payment Arrangement, Option, Exercise Price Range, Lower Range Limit (in dollars per share)	5.88
Share-Based Payment Arrangement, Option, Exercise Price Range, Upper Range Limit (in dollars per share)	$ 8.82
Number outstanding (in shares) | shares	130,000
Options outstanding, weighted average exercise price (in dollars per share)	$ 6.42
Options exercisable, number of shares (in shares) | shares	78,747
Options exercisable, weighted average exercise price (in dollars per share)	$ 6.36