Note 9 - Stockholders' Equity (Details) - Assumptions for Valuation of Waived Warrants Associated with Common Stock Offering	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Note 9 - Stockholders' Equity (Details) - Assumptions for Valuation of Waived Warrants Associated with Common Stock Offering [Line Items]
Risk-free interest rate	0.78%
Expected volatility	102.23%
Expected life (in years)	5 years
Expected forfeiture rate	0.00%
Expected dividend yield	0.00%
Waived Warrant [Member] | Minimum [Member]
Note 9 - Stockholders' Equity (Details) - Assumptions for Valuation of Waived Warrants Associated with Common Stock Offering [Line Items]
Risk-free interest rate	0.50%
Expected volatility	102.90%
Expected life (in years)	3 years 36 days
Waived Warrant [Member] | Maximum [Member]
Note 9 - Stockholders' Equity (Details) - Assumptions for Valuation of Waived Warrants Associated with Common Stock Offering [Line Items]
Risk-free interest rate	1.03%
Expected volatility	110.90%
Expected life (in years)	4 years 255 days
Expected forfeiture rate	0.00%
Expected dividend yield	0.00%
Minimum [Member]
Note 9 - Stockholders' Equity (Details) - Assumptions for Valuation of Waived Warrants Associated with Common Stock Offering [Line Items]
Risk-free interest rate	0.85%	1.60%
Expected volatility	83.41%	80.20%
Expected life (in years)	5 years 3 months	5 years
Expected forfeiture rate	5.00%	0.00%
Maximum [Member]
Note 9 - Stockholders' Equity (Details) - Assumptions for Valuation of Waived Warrants Associated with Common Stock Offering [Line Items]
Risk-free interest rate	1.19%	2.97%
Expected volatility	97.83%	82.30%
Expected life (in years)	6 years	6 years 3 months
Expected forfeiture rate	7.50%	7.50%
Expected dividend yield	0.00%	0.00%