Note 9 - Stockholders' Equity (Details) - Assumptions for Valuation of Waived Warrants Associated with Common Stock Offering	5 Months Ended	10 Months Ended	12 Months Ended
	Jun. 03, 2013	Oct. 28, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
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		6 years 3 months
Expected forfeiture rate	0.00%	0.00%	0.00%	7.50%	0.00%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%	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%	0.59%
Expected volatility	102.90%	105.10%
Expected life (in years)	3 years 36 days	2 years 255 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%	1.31%
Expected volatility	110.90%	111.80%
Expected life (in years)	4 years 255 days	4 years 109 days
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%	1.09%	2.29%
Expected volatility			83.40%	80.80%	72.20%
Expected life (in years)			5 years 3 months	5 years
Expected forfeiture rate			5.00%
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%	2.97%
Expected volatility			97.90%	82.30%	81.00%
Expected life (in years)			6 years	6 years 3 months
Expected forfeiture rate			7.50%