Note 7 - Equity Transactions - Summary of Warrants Outstanding, Exercise Price, and Expiration Dates (Details) - $ / shares	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Warrants Issued (in shares)	32,192,294	20,632,331	8,677,500
Warrants Expiring in April 2021 [Member]
Warrants Issued (in shares)	240,000
Exercise Price (in dollars per share)	$ 0.25
Warrants Expiring in July 2021 [Member]
Warrants Issued (in shares)	103,500
Exercise Price (in dollars per share)	$ 1
Warrants Expiring in July 2022 [Member]
Warrants Issued (in shares)	156,000
Exercise Price (in dollars per share)	$ 0.50
Warrants Expiring in August 2022 [Member]
Warrants Issued (in shares)	78,000
Exercise Price (in dollars per share)	$ 0.50
Warrants Expiring in June 2023 [Member]
Warrants Issued (in shares)	8,100,000
Exercise Price (in dollars per share)	$ 0.25
Warrants Expiring in February 2024 [Member]
Warrants Issued (in shares)	5,754,831
Exercise Price (in dollars per share)	$ 0.35
Warrants Expiring in October 2024 [Member]
Warrants Issued (in shares)	6,200,000
Exercise Price (in dollars per share)	$ 0.25
Warrants Expiring in April 23, 2025 [Member]
Warrants Issued (in shares)	8,040,000
Exercise Price (in dollars per share)	$ 0.25
Warrants Expiring in December, 2025 [Member]
Warrants Issued (in shares)	3,519,963
Exercise Price (in dollars per share)	$ 0.65