Note 8 - Preferred Stock and Common Stock Warrants (Details Textual) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended						3 Months Ended			6 Months Ended	9 Months Ended
	Oct. 15, 2021	Jul. 31, 2021	Apr. 30, 2021	Mar. 31, 2021	May 31, 2019	Sep. 30, 2018	Aug. 31, 2018	Sep. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2021	Sep. 30, 2021	Sep. 30, 2020
Gain (Loss) on Revaluation of Warrants								$ 4,442		$ (1,627)		$ (2,363)	$ 6,147
Series A Convertible Preferred Stock [Member]
Temporary Equity, Stock Issued During Period, Shares, New Issues (in shares)							50,000
Temporary Equity, Par or Stated Value Per Share (in dollars per share)							$ 0.0001
Temporary Equity, Issued Price Per Share (in dollars per share)							$ 1,000
Temporary Equity, Stock Issued During Period, Value, New Issues							$ 50,000
Temporary Equity, Stock Issued During Period, Shares Issued for Services (in shares)							1,000
Preferred Stock, Convertible, Conversion Price (in dollars per share)								$ 6.54				$ 6.54
Accretion of Discount Amount												$ 2,500
Series B Convertible Preferred Stock [Member]
Temporary Equity, Stock Issued During Period, Shares, New Issues (in shares)					20,945	29,055
Temporary Equity, Par or Stated Value Per Share (in dollars per share)						$ 0.0001
Temporary Equity, Issued Price Per Share (in dollars per share)					$ 1,000	$ 1,000
Temporary Equity, Stock Issued During Period, Value, New Issues					$ 20,945	$ 29,055
Temporary Equity, Stock Issued During Period, Shares Issued for Services (in shares)					418	581
Preferred Stock, Convertible, Conversion Price (in dollars per share)								6.57				$ 6.57
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, Par or Stated Value Per Share (in dollars per share)		$ 1,000	$ 1,000	$ 0.0001					$ 0.0001
Temporary Equity, Issued Price Per Share (in dollars per share)				$ 1,000					$ 1,000
Temporary Equity, Stock Issued During Period, Value, New Issues		$ 5,000	$ 10,000	$ 24,500
Temporary Equity, Stock Issued During Period, Shares Issued for Services (in shares)		100	200	490
Preferred Stock, Convertible, Conversion Price (in dollars per share)								3.29				3.29
Convertible Preferred Stock [Member]
Temporary Equity, Issued Price Per Share (in dollars per share)								$ 1,000				$ 1,000
Temporary Equity, Dividend Rate Percentage											12.00%
Dividends, Preferred Stock, Paid-in-kind												$ 13,000	$ 10,500
Convertible Preferred Stock [Member] | Subsequent Event [Member]
Dividends, Preferred Stock, Paid-in-kind	$ 5,300