v3.19.3
Note 10 - Warrants - Warrants Assumptions (Details) - Warrants for Series A Convertible Preferred Stock [Member]
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Jul. 01, 2010
Measurement Input, Risk Free Interest Rate [Member]      
Risk-free interest rate   2.28  
Measurement Input, Risk Free Interest Rate [Member] | Minimum [Member]      
Risk-free interest rate 2.56   0.0146
Measurement Input, Risk Free Interest Rate [Member] | Maximum [Member]      
Risk-free interest rate 2.59   0.0266
Measurement Input, Expected Term [Member] | Minimum [Member]      
Risk-free interest rate 6.92 7.92  
Measurement Input, Expected Term [Member] | Maximum [Member]      
Risk-free interest rate 7.08 8.08 7
Measurement Input, Price Volatility [Member]      
Risk-free interest rate   71.00  
Measurement Input, Price Volatility [Member] | Minimum [Member]      
Risk-free interest rate 76.84   0.736
Measurement Input, Price Volatility [Member] | Maximum [Member]      
Risk-free interest rate     0.815