Note 3 - Liquidity and Summary of Significant Accounting Principles - Anti-dilutive Securities 1 (Details) - shares	3 Months Ended		6 Months Ended		9 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Anti-dilutive securities (in shares)	14,633,795	8,459,167	8,453,795	8,459,167	8,453,795	8,459,167	1,588,334	14,633,795	31,858,610
Share-based Payment Arrangement, Option [Member]
Anti-dilutive securities (in shares)	1,355,001	1,355,001	1,355,001	1,355,001	1,355,001	1,355,001	1,355,001	1,355,001	1,741,876
Warrant [Member]
Anti-dilutive securities (in shares)	13,278,794	7,104,166	7,098,794	7,104,166	7,098,794	7,104,166	233,333	13,278,794	7,104,166