Note 9 - Preferred Stock and Common Stock Warrants (Details Textual) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended				12 Months Ended
	Jan. 17, 2023	Mar. 31, 2022	Jul. 31, 2021	Apr. 30, 2021	Mar. 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Gain (Loss) on Revaluation of Warrants						$ (5,747)	$ (2,533)
Series A Convertible Preferred Stock [Member]
Temporary Equity, Shares Outstanding (in shares)						82,948	73,713	65,507
Temporary Equity, Par or Stated Value Per Share (in dollars per share)						$ 0.0001		$ 0.0001
Preferred Stock, Convertible, Conversion Price (in dollars per share)						$ 5.48
Series B Convertible Preferred Stock [Member]
Temporary Equity, Shares Outstanding (in shares)						79,239	70,433	62,612
Temporary Equity, Par or Stated Value Per Share (in dollars per share)						$ 0.0001		$ 0.0001
Preferred Stock, Convertible, Conversion Price (in dollars per share)						$ 5.53
Series C Convertible Preferred Stock [Member]
Temporary Equity, Shares Outstanding (in shares)						59,366	42,490
Temporary Equity, Par or Stated Value Per Share (in dollars per share)					$ 0.0001	$ 0.0001
Temporary Equity, Stock Issued During Period, Shares, New Issues (in shares)		10,500,000	5,000	10,000	24,500
Temporary Equity, Issued Price Per Share (in dollars per share)		$ 1,000	$ 1,000	$ 1,000	$ 1,000
Temporary Equity, Stock Issued During Period, Value, New Issues		$ 10,500	$ 5,000	$ 10,000	$ 24,500
Temporary Equity, Stock Issued During Period, Shares Issued for Services (in shares)		210,000	100	200	490
Preferred Stock, Convertible, Conversion Price (in dollars per share)						2.98
Convertible Preferred Stock [Member]
Temporary Equity, Issued Price Per Share (in dollars per share)						$ 1,000
Temporary Stock, Threshold Trading Days for Conversion (Day)						60 days
Temporary Stock, Threshold Consecutive Trading Days for Conversion (Day)						90 days
Temporary Stock, Conversion Price Minimum Percentage						175.00%
Temporary Stock, Maximum Business Days Following FID Event for Conversion (Day)						10 days
Temporary Equity, Dividend Rate Percentage						12.00%
Dividends, Preferred Stock, Paid-in-kind						$ 24,300	$ 18,300
Convertible Preferred Stock [Member] | Subsequent Event [Member]
Dividends, Preferred Stock, Paid-in-kind	$ 6,700
Common Stock Warrants [Member]
Temporary Stock, Threshold Trading Days for Conversion (Day)						60 years
Temporary Stock, Threshold Consecutive Trading Days for Conversion (Day)						90 years
Exercise of Warrants, Percent of Fully Diluted Common Stock Acquirable						0.71%	0.86%
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)						$ 0.01
Warrants and Rights Outstanding, Term (Year)						3 years