Note 7 - Derivative Obligations - Fair Value Assumptions (Details) - Series A Warrant [Member]	Mar. 31, 2019	Dec. 31, 2018
Measurement Input, Share Price [Member]
Valuation assumption	0.29	0.27
Measurement Input, Price Volatility [Member]
Valuation assumption	0.96	0.94
Measurement Input, Expected Term [Member]
Valuation assumption	1.9	2.2
Measurement Input, Discount Rate [Member]
Valuation assumption	0.0228	0.0248
Measurement Input, Expected Dividend Rate [Member]
Valuation assumption	0	0
Measurement Input, Exercise Price [Member]
Valuation assumption	8	8