Note 8 - Preferred Stock and Common Stock Warrants (Details Textual) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions		1 Months Ended	3 Months Ended		6 Months Ended
	Jul. 15, 2022	Mar. 31, 2022	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Common Stock Warrants [Member]
Fair Value Adjustment of Warrants			$ 1.9	$ (4.8)	$ (4.4)	$ (6.8)
Series A Convertible Preferred Stock [Member]
Temporary Equity, Shares Outstanding (in shares)			78,181		78,181		73,713
Temporary Equity, Par or Stated Value Per Share (in dollars per share)							$ 0.0001
Preferred Stock, Convertible, Conversion Price (in dollars per share)			$ 6.14		$ 6.14
Series B Convertible Preferred Stock [Member]
Temporary Equity, Shares Outstanding (in shares)			74,694		74,694		70,433
Temporary Equity, Par or Stated Value Per Share (in dollars per share)							$ 0.0001
Preferred Stock, Convertible, Conversion Price (in dollars per share)			$ 6.19		$ 6.19
Series C Convertible Preferred Stock [Member]
Temporary Equity, Shares Outstanding (in shares)			55,961		55,961		42,490
Temporary Equity, Par or Stated Value Per Share (in dollars per share)							$ 0.0001
Temporary Equity, Stock Issued During Period, Shares, New Issues (in shares)		10,500
Temporary Equity, Issued Price Per Share (in dollars per share)		$ 1,000
Temporary Equity, Stock Issued During Period, Value, New Issues		$ 10.5
Temporary Equity, Stock Issued During Period, Shares Issued for Services (in shares)		210
Preferred Stock, Convertible, Conversion Price (in dollars per share)			$ 3.27		$ 3.27
Convertible Preferred Stock [Member]
Temporary Equity, Issued Price Per Share (in dollars per share)			$ 1,000		$ 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					$ 11.5	$ 7.7
Convertible Preferred Stock [Member] | Subsequent Event [Member]
Dividends, Preferred Stock, Paid-in-kind	$ 6.2