Note 10 - Stockholders' Equity (Details) (USD $) In Thousands, except Share data, unless otherwise specified	1 Months Ended	12 Months Ended				3 Months Ended	12 Months Ended			1 Months Ended			1 Months Ended			1 Months Ended				1 Months Ended			1 Months Ended	3 Months Ended	12 Months Ended			0 Months Ended	1 Months Ended	3 Months Ended		45 Months Ended	3 Months Ended		12 Months Ended
	Feb. 24, 2014	Dec. 31, 2013	Dec. 31, 2012	May 31, 2013	Mar. 31, 2014 Non-vested Stock Options, Restricted Stock and Restricted Stock Units [Member] Combined Equity Incentive Plans [Member]	Mar. 31, 2014 Non-vested Stock Options, Restricted Stock and Restricted Stock Units [Member] Combined Equity Incentive Plans [Member] Weighted-average remaining service period (Member)	Dec. 31, 2009 Scenario i (Member) 2009 Employee Stock Purchase Plan [Member]	Dec. 31, 2009 Scenario ii (Member) 2009 Employee Stock Purchase Plan [Member]	Feb. 24, 2014 Mistakenly Granted [Member]	Mar. 31, 2014 Note Warrant 1 [Member]	Mar. 31, 2014 Note Warrant 1 [Member] Minimum [Member]	Mar. 31, 2014 Note Warrant 1 [Member] Maximum [Member]	Mar. 31, 2014 Note Warrant 2 [Member]	Mar. 31, 2014 Note Warrant 2 [Member] Minimum [Member]	Mar. 31, 2014 Note Warrant 2 [Member] Maximum [Member]	Feb. 24, 2014 Warrant [Member]	Feb. 24, 2014 Warrant [Member] Minimum [Member]	Mar. 31, 2014 Warrant [Member] Minimum [Member]	Dec. 31, 2013 Warrant [Member] Minimum [Member]	Feb. 24, 2014 Warrant [Member] Maximum [Member]	Mar. 31, 2014 Warrant [Member] Maximum [Member]	Dec. 31, 2013 Warrant [Member] Maximum [Member]	Sep. 30, 2005 Maximum Maturity (Member) 2005 Equity Incentive Plan [Member]	Mar. 31, 2014 Immune Ltd Plan [Member]	Dec. 31, 2013 Immune Ltd Plan [Member]	Dec. 31, 2013 Immune Ltd Plan [Member] Minimum [Member]	Dec. 31, 2013 Immune Ltd Plan [Member] Maximum [Member]	Aug. 25, 2013 2005 Equity Incentive Plan [Member] Options Assumed in Merger [Member]	Sep. 30, 2005 2005 Equity Incentive Plan [Member]	Mar. 31, 2014 Combined Equity Incentive Plans [Member]	Mar. 31, 2013 Combined Equity Incentive Plans [Member]	Mar. 31, 2014 Combined Equity Incentive Plans [Member]	Mar. 31, 2014 2009 Employee Stock Purchase Plan [Member]	Mar. 31, 2013 2009 Employee Stock Purchase Plan [Member]	Dec. 31, 2013 Minimum [Member]	Dec. 31, 2012 Minimum [Member]	Dec. 31, 2013 Maximum [Member]	Dec. 31, 2012 Maximum [Member]
Note 10 - Stockholders' Equity (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized																								4,500,000					13,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures																								4,036,576	(4,036,576)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number			3,775,534																					2,495,951
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Number of Shares Per Employee																													1,500,000
Share-based Goods and Nonemployee Services Transaction, Valuation Method, Expected Term										5 years			5 years										10 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross		790,000	3,890,534																									2,495,951
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price		$ 1.15	$ 0.33																						$ 0.37	$ 0.03	$ 2.00	$ 0.60							$ 0.61	$ 0.03	$ 1.80	$ 2.00
Allocated Share-based Compensation Expense																														$ 1,864	$ 624	$ 9,681
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized					9,594
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition						1 year 219 days
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent							85.00%	85.00%
Stock Issued During Period, Shares, Employee Stock Purchase Plans																																	0	0
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant																																	998,043
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right, Percent									20.00%		50.00%	100.00%		50.00%	100.00%
Class of Warrant or Right, Number of Securities Called by Warrants or Rights				500,000						4.25
Warrant Exercise Price Conversion Percentage										125.00%			150.00%
Class of Warrant or Right, Exercise Price of Warrants or Rights	5.04									4.25			5.10					1.10	1.10		124.2000	124.2000
Noncash or Part Noncash Acquisition, Noncash Financial or Equity Instrument Consideration, Warrants Issued	134,004
Warrants and Rights Outstanding																$ 274
Fair Value Assumptions, Expected Term																	1 year 346 days			4 years 175 days
Fair Value Assumptions, Expected Volatility Rate																90.00%
Fair Value Assumptions, Risk Free Interest Rate																	0.27%