Note 7 - Options and Warrants to Purchase Common Stock - Summary of the Status and Changes of the Options Granted Under the Stock Option Plans and Other Agreements (Details) - $ / shares		9 Months Ended	12 Months Ended
		Sep. 30, 2017	Dec. 31, 2016
Outstanding, shares (in shares)		21,277,479
Outstanding, weighted average exercise price (in dollars per share)		$ 0.87
Outstanding, weighted average remaining contractual life (Year)	[1]	3 years 262 days	4 years
Issued (in shares)		650,000
Issued, weighted average exercise price (in dollars per share)		$ 0.25
Issued, weighted average remaining contractual life (Year)	[1]	4 years 273 days
Exercised (in shares)		0
Exercised (in dollars per share)		$ 0
Forfeited (in shares)		(30,000)
Forfeited (in dollars per share)		$ 1.55
Outstanding, shares (in shares)		21,897,479	21,277,479
Outstanding, weighted average exercise price (in dollars per share)		$ 0.85	$ 0.87
Exercisable, shares (in shares)		21,277,479
Exercisable, weighted average exercise price (in dollars per share)		$ 0.87
Exercisable, weighted average remaining contractual life (Year)	[1]	4 years 69 days

[1] Measured in years