Note 8 - Stock Options and Restricted Stock - Potentially Dilutive Instruments (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Potentially dilutive instruments (in shares)	1,358,691	466,125
Share-Based Payment Arrangement, Option [Member]
Potentially dilutive instruments (in shares)	3,621	93,747
Restricted Stock [Member]
Potentially dilutive instruments (in shares)	179,351	58,220
Warrant [Member]
Potentially dilutive instruments (in shares)	1,175,719	314,158