Note 9 - Share Based Payments - Stock Option Activity (Details) - USD ($)		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016
Shares under option (in shares)		2,220,000	2,405,000
Shares under option, Weighted average exercise price (in dollars per share)		$ 0.48	$ 0.48
Options granted, shares (in shares)		2,557,000	60,000
Options granted, Weighted average exercise price (in dollars per share)		$ 0.10	$ 0.10
Options exercised, shares (in shares)
Options exercised, Weighted average exercise price (in dollars per share)
Options cancelled and expired, shares (in shares)		(2,316,000)	(245,000)
Options cancelled and expired, Weighted average exercise price (in dollars per share)		$ (0.41)	$ (0.41)
Shares under option, Weighted average remaining contractual life (Year)		9 years 98 days	6 years 54 days
Shares under option, shares (in shares)		2,461,000	2,220,000
Shares under option, Weighted average exercise price (in dollars per share)		$ 0.15	$ 0.48
Shares under option, Aggregate intrinsic value	[1]	$ 687

[1] Aggregate intrinsic value includes only those options with intrinsic value (options where the exercise price is below the market price).