Note 8 - Convertible Preferred Stock Warrant Liabilities (Details) - Fair Value Assumptions	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Fair Value Assumptions [Abstract]
Dividend rate	0.00%	0.00%	0.00%	0.00%
Risk-free interest rate	1.50%	1.20%	1.50%	1.20%
Remaining contractual term (in years)	3 years 219 days	4 years 219 days	3 years 219 days	4 years 219 days
Expected volatility	40.00%	50.00%	40.00%	50.00%