Note 11 - Common stock warrants: Schedule of Series B and Series D common stock warrants (Details) - shares	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Series B
Warrants Outstanding, Starting Balance	87,456	87,456
Warrants Issued	0	0
Warrants Exercised	0	0
Warrants Outstanding, Ending Balance	87,456	87,456
Series D
Warrants Outstanding, Starting Balance	6,252,954	6,252,954
Warrants Issued	0	0
Warrants Exercised	0	0
Warrants Outstanding, Ending Balance	6,252,954	6,252,954
B and D Total
Warrants Outstanding, Starting Balance	6,340,410	6,340,410
Warrants Issued	0	0
Warrants Exercised	0	0
Warrants Outstanding, Ending Balance	6,340,410	6,340,410