Note 11 - Common Stock Equivalents Excluded from Calculation of Net Loss Per Share (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014		Dec. 31, 2013
Convertible Preferred Stock [Member]
Antidilutive Securities (in shares)		7,581	[1]	4,254
Common Stock Warrants [Member]
Antidilutive Securities (in shares)		660	[1]	660
Employee Stock Option [Member]
Antidilutive Securities (in shares)	2,200	1,236		607
Convertible Debt Securities [Member]
Antidilutive Securities (in shares)		243	[1]	243
Antidilutive Securities (in shares)	2,200	9,720		5,764

[1] These instruments were either exercised or converted to Common Stock during 2014.