Note 10 - Convertible Notes Payable - Related Parties - Convertible Notes Payable to Related Parties (Details) (Parentheticals) - Convertible Debt Payable to Related Party [Member]	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Bill Chaaban, President of Cen Biotech [Member]
Interest Rate		12.00%
Conversion Rights		867,576
Maturity date		Aug. 17, 2020
Director, Harold Aubrey de Lavenu [Member]
Interest Rate	5.00%	5.00%
Conversion Rights	548,980	548,980
Maturity date	Mar. 31, 2019	Mar. 31, 2019
Joseph Byrne [Member]
Interest Rate	12.00%	12.00%
Conversion Rights	76,123	76,123
Maturity date	Aug. 17, 2020	Aug. 17, 2020
Jeff Thomas [Member]
Interest Rate	5.00%	5.00%
Conversion Rights	94,488	94,488
Maturity date	May 24, 2022	May 24, 2022
Director, Alex Tarrabain [Member]
Interest Rate		5.00%
Conversion Rights		30,000
Brother of Director Ameen Ferris [Member]
Interest Rate		5.00%
Conversion Rights		12,500