Note 18 - Warrant Liabilities - Fair Value of Warrants (Details)	Sep. 30, 2019 yr	Jun. 30, 2019 yr	Dec. 31, 2018 yr	Sep. 30, 2018 yr	Jun. 30, 2018 yr	Jan. 17, 2018 yr
Measurement Input, Share Price [Member] | Investor Warrants [Member]
Fair value of the warrants	1.3	1.35	1.34	1.73	2.52	3.98
Measurement Input, Share Price [Member] | Placement Agent Warrants [Member]
Fair value of the warrants	1.3	1.35	1.34	1.73	2.52	3.98
Measurement Input, Expected Term [Member] | Investor Warrants [Member]
Fair value of the warrants	0.8	1.05	1.55	1.8	2.05	2.5
Measurement Input, Expected Term [Member] | Placement Agent Warrants [Member]
Fair value of the warrants	1.3	1.55	2.05	2.3	2.55	3
Measurement Input, Risk Free Interest Rate [Member] | Investor Warrants [Member]
Fair value of the warrants	0.0179	0.0173	0.025	0.028	0.0253	0.0222
Measurement Input, Risk Free Interest Rate [Member] | Placement Agent Warrants [Member]
Fair value of the warrants	0.0157	0.0173	0.025	0.0282	0.0256	0.0239
Measurement Input, Expected Dividend Rate [Member] | Investor Warrants [Member]
Fair value of the warrants
Measurement Input, Expected Dividend Rate [Member] | Placement Agent Warrants [Member]
Fair value of the warrants
Measurement Input, Price Volatility [Member] | Investor Warrants [Member]
Fair value of the warrants	0.82	0.9	1.99	1.83	1.74	1.58
Measurement Input, Price Volatility [Member] | Placement Agent Warrants [Member]
Fair value of the warrants	0.83	2.02	1.76	1.66	1.59	1.47
Measurement Input, Exercise Price [Member] | Investor Warrants [Member]
Fair value of the warrants	1.4927	6.6	6.6	6.6	6.6	6.6
Measurement Input, Exercise Price [Member] | Placement Agent Warrants [Member]
Fair value of the warrants	1.4927	6.6	6.6	6.6	6.6	6.6
Measurement Input, Quoted Price [Member] | Investor Warrants [Member]
Fair value of the warrants	0.31	0.05	0.78	1.06	1.71	2.93
Measurement Input, Quoted Price [Member] | Placement Agent Warrants [Member]
Fair value of the warrants	0.43	0.8	0.8	1.1	1.74	2.99