Note 12 - Embedded Derivatives (Details Textual) $ / shares in Units, $ in Millions		Dec. 31, 2021 USD ($) $ / shares shares		Aug. 31, 2020 shares	Aug. 25, 2020 $ / shares shares	Jul. 31, 2020 shares	Jul. 06, 2020 shares	Dec. 31, 2019 shares
Class of Warrant or Right, Outstanding (in shares)		97,734
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)		97,734						30,315,986
Measurement Input, Price Volatility [Member]
Warrants and Rights Outstanding, Measurement Input		130
Measurement Input, Risk Free Interest Rate [Member]
Warrants and Rights Outstanding, Measurement Input		0.31
Measurement Input, Expected Term [Member]
Warrants and Rights Outstanding, Measurement Input		5
The Series 2020 A Warrants [Member]
Class of Warrant or Right, Outstanding (in shares)		90,608
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares	[1]	$ 0.60
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)		90,608	[1]			30,000,000		30,000,000	[1]
Warrants and Rights Outstanding | $		$ 8.3
Series 2020 B Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)						9,103,334	30,000,000
Warrants and Rights Outstanding | $		2.9
Series 2020C Warrants [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares					$ 0.01
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)				16,532,232	16,532,232
Warrants and Rights Outstanding | $		$ 21.4
Minimum [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares		$ 0.60
Minimum [Member] | Measurement Input, Price Volatility [Member]
Warrants and Rights Outstanding, Measurement Input		130
Minimum [Member] | Measurement Input, Risk Free Interest Rate [Member]
Warrants and Rights Outstanding, Measurement Input		0.30
Maximum [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares		$ 2.00
Maximum [Member] | Measurement Input, Price Volatility [Member]
Warrants and Rights Outstanding, Measurement Input		141
Maximum [Member] | Measurement Input, Risk Free Interest Rate [Member]
Warrants and Rights Outstanding, Measurement Input		0.31

[1] The Series 2020-A Warrants are equity-classified warrants.