Note 13 - Warrants (Tables)

9 Months Ended

Sep. 30, 2014

Note 13 - Warrants (Tables) [Line Items]

Schedule of Warrant Activity [Table Text Block]

Warrants	Number of Warrants Issued		Weighted Average Exercise Price
Warrants outstanding at December 31, 2013		3,170,520	$	10.65
Warrants granted in connection with the January 2014 Common Stock Offering, as more fully described in Note 11		1,801,802	$	4.10
Increase in number shares associated with the Hercules Warrant (see Note 10)		97,493	$	3.59
Warrants exercised for common stock		–	$	–
Warrants outstanding at September 30, 2014		5,069,815	$	8.18
Aggregate intrinsic value of outstanding warrants at September 30, 2014	$	–
Weighted average remaining contractual terms (in years)		2.6

Schedule of Common Stock Warrant Liability Valuation Assumptions [Table Text Block]

	September 30, 2014			December 31, 2013
Risk-free interest rate		0.03 - 1.78	%		0.13	%
Expected volatility		24.1 - 103.4	%		64.74	%
Expected life (in years)		0.5 - 4.2			1.25
Expected forfeiture rate		0.0	%		0.0	%
Expected dividend yield		0.00	%		0.00	%

	June 3, 2013			June 30, 2013
Risk-free interest rate		0.50 - 1.03	%		0.36 - 1.41	%
Expected volatility		102.9 - 110.9	%		103.4 - 147.3	%
Expected life (in years)		3.1 - 4.7			1.75 - 4.70
Expected forfeiture rate		0.0	%		0.0	%
Expected dividend yield		0.00	%		0.00	%

Schedule of Common Stock Warranty Liability [Table Text Block]

Beginning balance as of January 1, 2014	$	3,026
Fair value of warrants classified as liability (see Note 10)		476,261
Gain from the adjustment for the change in fair value included in net income		(81,243	)
Ending balance as of September 30, 2014	$	398,044

Waived Warrants [Member]

Note 13 - Warrants (Tables) [Line Items]

Schedule of Stockholders' Equity Note, Warrants or Rights [Table Text Block]

Shares of common stock associated with the Waived Warrants	Expiration Date of Waived Warrants	Strike Price		Per Share Fair Value on June 3, 2013		Per Share Fair Value on June 30, 2013
1,323,496	2/26/2018	$	5.31	$	6.60	$	3.33
31,243	7/25/2016	$	18.99	$	4.41	$	1.93
12,628	7/6/2016	$	14.09	$	4.81	$	2.15
31,448	11/25/2017	$	12.47	$	5.56	$	2.66

September 2009 Warrants [Member]

Note 13 - Warrants (Tables) [Line Items]

Schedule of Stockholders' Equity Note, Warrants or Rights [Table Text Block]

Shares of common stock associated with warrants issued in the September 2009 registered direct offering		Expiration Date of warrants issued in the September 2009 registered direct offering	Strike Price		Per Share Fair Value on June 30, 2013
	448,478	March 31, 2015	$	23.58	$	0.71