v3.23.2
Note 9 - Long-term Debt (Details Textual) - USD ($)
 12 Months Ended
May 30, 2019
Dec. 31, 2022
Dec. 31, 2021
Repayments of Long-term Debt, Total   $ 8,433,000 $ 8,833,000
Long-Term Debt, Total   5,363,000  
Amortization of Debt Discount (Premium)   393,000 761,000
Warrant In Connection with Oxford Finance Loan Agreement [Member]      
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) 8,833    
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) $ 56.60    
Loan Agreement with Oxford Finance LLC [Member]      
Debt Instrument, Face Amount $ 25,000,000.0    
Repayments of Long-term Debt, Total 8,900,000    
Proceeds from Debt, Net of Issuance Costs and Repayment of Debt $ 15,900,000    
Debt Instrument, Interest Rate, Base Percentage 2.50%    
Prepayment Charge, Percentage of Outstanding Balance, After May 30, 2020, Before May 30, 2021 1.00%    
Debt Instrument, Covenant, Minimum Required Unrestircted Cash $ 5,000,000.0    
Debt Instrument, Minimum Indebtedness Amount with Acceleration Right 250,000    
Loan Default Events, Trigger of Negative Impact of Government Approvals and Judgments $ 500,000    
Debt Instrument, Default Additional Interest Rate 5.00%    
Fair Value of Contingent Put Option, Liability   10,000  
Long-Term Debt, Total   5,400,000 13,300,000
Interest Expense, Debt, Total   1,100,000 2,200,000
Amortization of Debt Discount (Premium)   $ 400,000 $ 700,000
Debt Instrument, Interest Rate, Effective Percentage   13.60% 13.20%
Loan Agreement with Oxford Finance LLC [Member] | London Interbank Offered Rate LIBOR 1 [Member]      
Debt Instrument, Basis Spread on Variable Rate 6.75%