Note 7 - Warrants and Registration Rights Agreements - Summary of the Warrants Issued and Changes (Details)	6 Months Ended
	Jun. 30, 2019 $ / shares shares
Outstanding, beginning balance (in shares) | shares	20,140,731
Outstanding, weighted average exercise price (in dollars per share) | $ / shares	$ 0.15
Granted (in shares) | shares	500,000
Granted, weighted average exercise price (in dollars per share) | $ / shares	$ 0.76
Canceled / Expired (in shares) | shares	(500,000)
Canceled / expired, weighted average exercise price (in dollars per share) | $ / shares	$ 0.76
Exercised (in shares) | shares
Exercised, weighted average exercise price (in dollars per share) | $ / shares
Outstanding, ending balance (in shares) | shares	20,140,731
Outstanding, weighted average exercise price (in dollars per share) | $ / shares	$ 0.15