Note 16 - Subsequent Events (Details Textual) - USD ($) $ / shares in Units, $ in Millions			1 Months Ended			3 Months Ended
	Mar. 14, 2022	Mar. 02, 2022	Jul. 31, 2021	Apr. 30, 2021	Mar. 31, 2021	Mar. 31, 2021
Subsequent Event [Member] | Tep Next Decade, LLC [Member] | Common Stock Warrants [Member]
Exercise of Warrants, Percent of Fully Diluted Common Stock Acquirable		0.071%
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)		$ 0.01
Subsequent Event [Member] | Avenue Energy Opportunities Fund Ii, L.P. [Member] | Common Stock Warrants [Member]
Exercise of Warrants, Percent of Fully Diluted Common Stock Acquirable	0.0781%
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)	$ 0.01
Series C Convertible Preferred Stock [Member]
Temporary Equity, Stock Issued During Period, Shares, New Issues (in shares)			5,000	10,000		24,500
Temporary Equity, Issued Price Per Share (in dollars per share)					$ 1,000	$ 1,000
Temporary Equity, Stock Issued During Period, Value, New Issues			$ 5.0	$ 10.0	$ 24.5
Temporary Equity, Stock Issued During Period, Shares Issued for Services (in shares)			100	200	490
Series C Convertible Preferred Stock [Member] | Subsequent Event [Member] | Tep Next Decade, LLC [Member]
Temporary Equity, Stock Issued During Period, Shares, New Issues (in shares)		5,000
Temporary Equity, Issued Price Per Share (in dollars per share)		$ 1,000
Temporary Equity, Stock Issued During Period, Value, New Issues		$ 5.0
Temporary Equity, Stock Issued During Period, Shares Issued for Services (in shares)		100
Series C Convertible Preferred Stock [Member] | Subsequent Event [Member] | Avenue Energy Opportunities Fund Ii, L.P. [Member]
Temporary Equity, Stock Issued During Period, Shares, New Issues (in shares)	5,500
Temporary Equity, Issued Price Per Share (in dollars per share)	$ 1,000
Temporary Equity, Stock Issued During Period, Value, New Issues	$ 5.5
Temporary Equity, Stock Issued During Period, Shares Issued for Services (in shares)	110