Note 2 - Summary of Significant Accounting Policies - Anti-dilutive Securities (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Antidilutive Securities (in shares)	1,072,960	207,675	1,008,832	207,627
Common Stock Warrants [Member]
Antidilutive Securities (in shares)	1,006,285	137,700	939,419	137,700
Common Stock Options [ member]
Antidilutive Securities (in shares)	303	304	303	304
Preferred Stock [Member]
Antidilutive Securities (in shares)	57,295	48,503	59,636	48,503
Restricted Stock Units (RSUs) [Member]
Antidilutive Securities (in shares)	9,077	21,168	9,474	21,120