Note 9 - Stockholders' Equity - Stock Option Activity (Details)	9 Months Ended
	Sep. 30, 2019 $ / shares shares
Outstanding, number of options, balance (in shares) | shares	3,575,000
Outstanding, weighted average exercise price, balance (in dollars per share) | $ / shares	$ 0.45
Granted, number of options (in shares) | shares
Granted, weighted average exercise price (in dollars per share) | $ / shares
Exercised, number of options (in shares) | shares	0
Exercised, weighted average exercise price (in dollars per share) | $ / shares
Cancelled, number of options (in shares) | shares	(249,250)
Cancelled, weighted average exercise price (in dollars per share) | $ / shares	$ (0.42)
Outstanding, number of options, balance (in shares) | shares	3,325,750
Outstanding, weighted average exercise price, balance (in dollars per share) | $ / shares	$ 0.45