Note 9 - Stock Options and Restricted Stock - Potentially Dilutive Instruments (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Potentially dilutive instruments (in shares)	1,192,085	1,195,019	1,192,832	1,174,405
Share-Based Payment Arrangement, Option [Member]
Potentially dilutive instruments (in shares)	0	2,934	747	4,201
Warrant [Member]
Potentially dilutive instruments (in shares)	1,192,085	1,192,085	1,192,085	1,170,204