Note 5 - Stock-based Compensation - Stock Options Outstanding and Exercisable (Details)	6 Months Ended
	Jun. 30, 2024 USD ($) $ / shares shares
Share-Based Payment Arrangement, Option, Exercise Price Range, Lower Range Limit (in dollars per share)	$ 3.5
Share-Based Payment Arrangement, Option, Exercise Price Range, Upper Range Limit (in dollars per share)	$ 39.11
Share-Based Payment Arrangement, Options, Outstanding, Number (in shares) | shares	59,000
Share-Based Payment Arrangement, Options, Outstanding, Weighted Average Remaining Contractual Term (Year)	4 years 1 month 6 days
Share-Based Payment Arrangement, Options, Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 17.35
Share-Based Payment Arrangement, Options, Outstanding, Intrinsic Value | $	$ 195,250
Options Outstanding Exercise Price Range1 [Member]
Share-Based Payment Arrangement, Option, Exercise Price Range, Lower Range Limit (in dollars per share)	$ 3.5
Share-Based Payment Arrangement, Option, Exercise Price Range, Upper Range Limit (in dollars per share)	$ 3.86
Share-Based Payment Arrangement, Options, Outstanding, Number (in shares) | shares	13,000
Share-Based Payment Arrangement, Options, Outstanding, Weighted Average Remaining Contractual Term (Year)	2 years 8 months 12 days
Share-Based Payment Arrangement, Options, Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 3.75
Share-Based Payment Arrangement, Options, Outstanding, Intrinsic Value | $	$ 140,930
Options Outstanding Exercise Price Range2 [Member]
Share-Based Payment Arrangement, Option, Exercise Price Range, Upper Range Limit (in dollars per share)	$ 7.8
Share-Based Payment Arrangement, Options, Outstanding, Number (in shares) | shares	8,000
Share-Based Payment Arrangement, Options, Outstanding, Weighted Average Remaining Contractual Term (Year)	3 years 10 months 24 days
Share-Based Payment Arrangement, Options, Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 7.8
Share-Based Payment Arrangement, Options, Outstanding, Intrinsic Value | $	$ 54,320
Options Outstanding Exercise Price Range 3 [Member]
Share-Based Payment Arrangement, Option, Exercise Price Range, Upper Range Limit (in dollars per share)	$ 19.99
Share-Based Payment Arrangement, Options, Outstanding, Number (in shares) | shares	30,000
Share-Based Payment Arrangement, Options, Outstanding, Weighted Average Remaining Contractual Term (Year)	4 years 7 months 6 days
Share-Based Payment Arrangement, Options, Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 19.99
Share-Based Payment Arrangement, Options, Outstanding, Intrinsic Value | $	$ 0
Options Outstanding Exercise Price Range 4 [Member]
Share-Based Payment Arrangement, Option, Exercise Price Range, Upper Range Limit (in dollars per share)	$ 39.11
Share-Based Payment Arrangement, Options, Outstanding, Number (in shares) | shares	8,000
Share-Based Payment Arrangement, Options, Outstanding, Weighted Average Remaining Contractual Term (Year)	4 years 10 months 24 days
Share-Based Payment Arrangement, Options, Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 39.11
Share-Based Payment Arrangement, Options, Outstanding, Intrinsic Value | $	$ 0