Note 8 - Preferred Stock and Common Stock Warrants (Details Textual) - USD ($) $ / shares in Units, $ in Thousands			1 Months Ended			3 Months Ended
	Apr. 15, 2021	Apr. 12, 2021	May 31, 2019	Sep. 30, 2018	Aug. 31, 2018	Mar. 31, 2021	Mar. 31, 2020
Fair Value Adjustment of Warrants						$ 2,000	$ (8,300)
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)						$ 6.84
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
Series C Convertible Preferred Stock [Member]
Temporary Equity, Stock Issued During Period, Shares, New Issues (in shares)						24,500
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						$ 24,500
Temporary Equity, Stock Issued During Period, Shares Issued for Services (in shares)						490
Preferred Stock, Convertible, Conversion Price (in dollars per share)						$ 2.96
Series C Convertible Preferred Stock [Member] | Subsequent Event [Member]
Temporary Equity, Stock Issued During Period, Shares, New Issues (in shares)		10,000
Temporary Equity, Issued Price Per Share (in dollars per share)		$ 1,000
Temporary Equity, Stock Issued During Period, Value, New Issues		$ 10,000
Temporary Equity, Stock Issued During Period, Shares Issued for Services (in shares)		200
Convertible Preferred Stock [Member]
Temporary Equity, Issued Price Per Share (in dollars per share)						$ 1,000
Temporary Equity, Dividend Rate Percentage						12.00%
Dividends, Preferred Stock, Paid-in-kind						$ 3,900	$ 3,400
Convertible Preferred Stock [Member] | Subsequent Event [Member]
Dividends, Preferred Stock, Paid-in-kind	$ 3,900