Note 3 - Net Loss Per Share - Antidilutive Securities (Details) - shares	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Total potential dilutive shares (in shares)	4,745,305	2,387,480
Share-Based Payment Arrangement, Option [Member]
Total potential dilutive shares (in shares)	1,012,456	525,247
Performance Shares [Member]
Total potential dilutive shares (in shares)	2,123,333	252,717
Shares Reserved for Convertible Notes [Member]
Total potential dilutive shares (in shares)	547,592	547,592
Warrant [Member]
Total potential dilutive shares (in shares)	1,061,924	1,061,924