Note 10 - Commitments and Contingencies - Valuation Assumptions (Details)	Dec. 31, 2018 yr
Measurement Input, Share Price [Member]
Call Option, Measurement Input	10.75
Measurement Input, Exercise Price [Member]
Call Option, Measurement Input	10
Measurement Input, Expected Term [Member]
Call Option, Measurement Input	5
Measurement Input, Price Volatility [Member]
Call Option, Measurement Input	0.6
Measurement Input, Risk Free Interest Rate [Member]
Call Option, Measurement Input	0.0158
Measurement Input, Expected Dividend Rate [Member]
Call Option, Measurement Input	0