Note 8 - Common Stock - Outstanding Stock Purchase Warrants (Details) - $ / shares		Jun. 30, 2015	Dec. 31, 2014
Series D Warrants [Member] | Placement Agent for Offering [Member]
Issued – Series D Warrants (1) (in shares)	[1]	1,333,333
Class of Warrant or Right, Exercise Price of Warrants or Rights	[1]	$ 0.17
Series D Warrants [Member]
Issued – Series D Warrants (1) (in shares)	[1]	16,666,666
Class of Warrant or Right, Exercise Price of Warrants or Rights	[1]	$ 0.17
Series E Warrants [Member]
Issued – Series D Warrants (1) (in shares)	[1]	16,666,666
Class of Warrant or Right, Exercise Price of Warrants or Rights	[1]	$ 0.14
Series F Warrants [Members]
Issued – Series D Warrants (1) (in shares)	[1]	16,666,666
Class of Warrant or Right, Exercise Price of Warrants or Rights	[1]	$ 0.17
Issued – Series D Warrants (1) (in shares)		56,442,157	5,108,826
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 0.20	$ 0.66
Warrants exercisable (in shares)		39,775,491
Warrants exercisable, weighted average exercise price (in dollars per share)		$ 0.21

[1] See discussion under “Series C Convertible Preferred Stock” in Note 7.