Note 8 - Convertible Preferred Stock Warrant Liabilities (Details) - Warrants Issued and Outstanding (USD $) In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Class of Warrant or Right [Line Items]
Number of Warrants Issued and Outstanding	113	113
Fair Value	$ 909	$ 760
Convertible Preferred Series BB Stock [Member] | December 2007 Warrants [Member]
Class of Warrant or Right [Line Items]
Number of Warrants Issued and Outstanding	23	23
Exercise Price per Share	$ 6.50
Fair Value	164	129
Convertible Preferred Series BB Stock [Member] | November 2008 Warrants [Member]
Class of Warrant or Right [Line Items]
Number of Warrants Issued and Outstanding	54	54
Exercise Price per Share	$ 6.50
Fair Value	438	371
Convertible Preferred Series BB Stock [Member] | March 2009 Warrants [Member]
Class of Warrant or Right [Line Items]
Number of Warrants Issued and Outstanding	21	21
Exercise Price per Share	$ 6.50
Fair Value	179	151
Convertible Preferred Series BB Stock [Member] | March 2010 Warrants [Member]
Class of Warrant or Right [Line Items]
Number of Warrants Issued and Outstanding	15	15
Exercise Price per Share	$ 6.50
Fair Value	$ 128	$ 109