Note 11 - Fair Value Measures (Details) - Summary of Changes in Convertible Notes, Warrants, Options (USD $)	0 Months Ended	1 Months Ended		3 Months Ended
	Jan. 16, 2013	Mar. 31, 2013	Feb. 22, 2013	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Balance	$ 12,592,000	$ 21,963,000	$ 17,490,000	$ 8,595,000	$ 21,963,000	$ 7,217,000	$ 11,898,000
Allocation of initial proceeds	250,000
Amortization of debt discount			95,000		95,000
Exercise of warrants		(844,000)
Fair value adjustment	444,000	5,317,000	(450,000)	1,378,000
Carrying value of old debt at modification			(8,137,000)
Fair value of new debt at modification			7,972,000
Modification of warrants			2,548,000
Cancellation/retirement of warrants			(1,100,000)
Fair value of instruments at issuance			3,970,000
2011 Warrants [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Balance	2,000,000	5,086,000	3,916,000	358,000	5,086,000	179,000	2,000,000
Exercise of warrants		(844,000)
Fair value adjustment		2,014,000		179,000
Modification of warrants			1,916,000
2012 Warrants [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Balance	1,800,000	1,958,000	1,632,000	159,000	1,958,000	141,000	1,800,000
Fair value adjustment		326,000		18,000
Modification of warrants			632,000
Cancellation/retirement of warrants			(800,000)
Third Tranche Warrants [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Balance	300,000
Allocation of initial proceeds	108,000
Fair value adjustment	192,000
Cancellation/retirement of warrants			(300,000)
February 2013 Warrants [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Balance		3,643,000	2,759,000	1,981,000	3,643,000	1,441,000
Fair value adjustment		884,000		540,000
Fair value of instruments at issuance			2,759,000
February 2013 SPA Option [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Balance		1,794,000	1,211,000		1,794,000
Fair value adjustment		583,000
Fair value of instruments at issuance			1,211,000
September 2013 Warrants [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Balance				842,000		627,000
Fair value adjustment				215,000
September 2013 SPA Option [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Balance				351,000		292,000
Fair value adjustment				59,000
2011 Convertible Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Balance	6,510,000	7,200,000	6,070,000	3,490,000	7,200,000	3,290,000	6,510,000
Amortization of debt discount			38,000
Fair value adjustment		1,130,000	(370,000)	200,000
Carrying value of old debt at modification			(6,178,000)
Fair value of new debt at modification			6,070,000
2012 Convertible Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Balance	1,588,000	1,800,000	1,516,000	1,130,000	1,800,000	1,010,000	1,588,000
Amortization of debt discount			55,000
Fair value adjustment		284,000	(72,000)	120,000
Carrying value of old debt at modification			(1,571,000)
Fair value of new debt at modification			1,516,000
Third Tranche Convertible Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Balance	394,000	482,000	386,000	284,000	482,000	237,000
Allocation of initial proceeds	142,000
Amortization of debt discount			2,000
Fair value adjustment	252,000	96,000	(8,000)	47,000
Carrying value of old debt at modification			(388,000)
Fair value of new debt at modification			$ 386,000