Note 15 - Common stock warrants: Schedule of Series B and Series D common stock warrants (Details) - shares		3 Months Ended	12 Months Ended
		Mar. 31, 2019	Dec. 31, 2018
Series B
Warrants Outstanding, Starting Balance		87,456	0
Common Stock Warrants Reinstated	[1]	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	6,666,007
Common Stock Warrants Reinstated	[1]	29,544
Warrants Issued		0	0
Warrants Exercised		0	(442,597)
Warrants Outstanding, Ending Balance		6,252,954	6,252,954
B and D Total
Warrants Outstanding, Starting Balance		6,340,410	6,666,007
Common Stock Warrants Reinstated	[1]	117,000
Warrants Issued		0	0
Warrants Exercised		0	(442,597)
Warrants Outstanding, Ending Balance		6,340,410	6,340,410

[1] See Note 5.