v3.23.2
Note 12 - Warrants (Details Textual)
1 Months Ended 12 Months Ended
Dec. 29, 2022
USD ($)
$ / shares
shares
Dec. 27, 2022
$ / shares
shares
Aug. 03, 2022
USD ($)
$ / shares
shares
Nov. 17, 2021
USD ($)
$ / shares
shares
Nov. 15, 2021
USD ($)
$ / shares
shares
Dec. 31, 2022
USD ($)
$ / shares
shares
Dec. 31, 2022
USD ($)
$ / shares
shares
Dec. 31, 2021
USD ($)
$ / shares
Oct. 25, 2022
$ / shares
Dec. 31, 2020
shares
May 30, 2019
USD ($)
$ / shares
yr
shares
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares           $ 0.001 $ 0.001 $ 0.001 $ 0.001    
Equity Issuance Costs, Modification of Warrants             $ 47,000 $ 0      
Warrants and Rights Outstanding           $ 7,098,000 $ 7,098,000 0      
Redeemable Convertible Preferred Stock [Member]                      
Stock Issued During Period, Shares, New Issues (in shares) | shares     3,000                
Proceeds from Issuance or Sale of Equity, Net     $ 129,000                
The 2022 Prefunded Warrants [Member]                      
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares   2,632,898                  
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares $ 0.0001                    
Equity Offering, Price Per Unit (in dollars per share) | $ / shares $ 2.22615                    
Warrants and Rights Outstanding, Measurement Input (in dollars per share) | $ / shares 2.22615                    
Class of Warrant or Right, Outstanding (in shares) | shares           2,632,898 2,632,898        
Common Warrants [Member]                      
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares   4,227,052                  
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares $ 2.07                    
Class of Warrant or Right, Outstanding (in shares) | shares           4,227,052 4,227,052        
December 2022 Financing [Member]                      
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares $ 2.07                    
Warrants and Rights Outstanding $ 7,100,000                    
Proceeds from Issuance of Warrants $ 335,000                    
December 2022 Financing [Member] | Measurement Input, Share Price [Member]                      
Warrants and Rights Outstanding, Measurement Input (in dollars per share) | $ / shares 2.13                    
December 2022 Financing [Member] | Measurement Input, Expected Term [Member]                      
Warrants and Rights Outstanding, Measurement Input (in dollars per share) 6                    
December 2022 Financing [Member] | Measurement Input, Price Volatility [Member]                      
Warrants and Rights Outstanding, Measurement Input (in dollars per share) 0.9544                    
December 2022 Financing [Member] | Measurement Input, Risk Free Interest Rate [Member]                      
Warrants and Rights Outstanding, Measurement Input (in dollars per share) 0.0393                    
December 2022 Financing [Member] | Measurement Input, Expected Dividend Rate [Member]                      
Warrants and Rights Outstanding, Measurement Input (in dollars per share) 0                    
December 2022 Financing [Member] | Minimum [Member]                      
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares $ 1.00                    
August 2022 LPC Warrant [Member]                      
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares     81,150                
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares $ 2.07   $ 4.07     $ 2.07 $ 2.07        
Warrants and Rights Outstanding     $ 300,000                
Proceeds from Issuance or Sale of Equity, Net     $ 110,000                
August 2022 LPC Warrant [Member] | Measurement Input, Share Price [Member]                      
Warrants and Rights Outstanding, Measurement Input (in dollars per share) | $ / shares     4.44                
August 2022 LPC Warrant [Member] | Measurement Input, Expected Term [Member]                      
Warrants and Rights Outstanding, Measurement Input (in dollars per share)     5.5                
August 2022 LPC Warrant [Member] | Measurement Input, Price Volatility [Member]                      
Warrants and Rights Outstanding, Measurement Input (in dollars per share)     0.8994                
August 2022 LPC Warrant [Member] | Measurement Input, Risk Free Interest Rate [Member]                      
Warrants and Rights Outstanding, Measurement Input (in dollars per share)     0.0286                
August 2022 LPC Warrant [Member] | Measurement Input, Expected Dividend Rate [Member]                      
Warrants and Rights Outstanding, Measurement Input (in dollars per share)     0                
November 2021 Financing Warrants [Member]                      
Stock Issued During Period, Shares, New Issues (in shares) | shares         875,000            
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares         875,000 125,000 125,000        
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares       $ 20.00 $ 20.00 $ 20.00 $ 20.00        
Warrants and Rights Outstanding       $ 5,600,000 $ 8,600,000            
Proceeds from Issuance of Warrants         $ 5,600,000            
November 2021 Financing Warrants [Member] | Measurement Input, Share Price [Member]                      
Warrants and Rights Outstanding, Measurement Input (in dollars per share)         14.92            
November 2021 Financing Warrants [Member] | Measurement Input, Expected Term [Member]                      
Warrants and Rights Outstanding, Measurement Input (in dollars per share)         5            
November 2021 Financing Warrants [Member] | Measurement Input, Price Volatility [Member]                      
Warrants and Rights Outstanding, Measurement Input (in dollars per share)         0.9177            
November 2021 Financing Warrants [Member] | Measurement Input, Risk Free Interest Rate [Member]                      
Warrants and Rights Outstanding, Measurement Input (in dollars per share)         0.0126            
November 2021 Financing Warrants [Member] | Measurement Input, Expected Dividend Rate [Member]                      
Warrants and Rights Outstanding, Measurement Input (in dollars per share)         0            
November 2021 Financing Warrants [Member] | Maximum [Member]                      
Class of Warrant or Right, Required Percentage of Ownership to Become Exercisable         9.99%            
Modified November 2021 Warrants [Member]                      
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares 750,000                    
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares $ 2.07                    
Equity Issuance Costs, Modification of Warrants $ 800,000                    
Modified November 2021 Warrants [Member] | Additional Paid-in Capital [Member]                      
Equity Issuance Costs, Modification of Warrants 100,000                    
Modified November 2021 Warrants [Member] | Selling, General and Administrative Expenses [Member]                      
Equity Issuance Costs, Modification of Warrants $ 700,000                    
Modified November 2021 Warrants [Member] | Measurement Input, Share Price [Member]                      
Warrants and Rights Outstanding, Measurement Input (in dollars per share) | $ / shares 2.13                    
Modified November 2021 Warrants [Member] | Measurement Input, Expected Term [Member]                      
Warrants and Rights Outstanding, Measurement Input (in dollars per share) 6                    
Modified November 2021 Warrants [Member] | Measurement Input, Price Volatility [Member]                      
Warrants and Rights Outstanding, Measurement Input (in dollars per share) 0.9544                    
Modified November 2021 Warrants [Member] | Measurement Input, Risk Free Interest Rate [Member]                      
Warrants and Rights Outstanding, Measurement Input (in dollars per share) 0.0393                    
Modified November 2021 Warrants [Member] | Measurement Input, Expected Dividend Rate [Member]                      
Warrants and Rights Outstanding, Measurement Input (in dollars per share) 0                    
Warrant In Connection with Oxford Finance Loan Agreement [Member]                      
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares                     8,833
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares                     $ 56.60
Warrants and Rights Outstanding                     $ 400,000
Class of Warrant or Right, Outstanding (in shares) | shares                   8,833  
Warrants and Rights Outstanding, Term (Year)                     10 years
Warrant In Connection with Oxford Finance Loan Agreement [Member] | Measurement Input, Share Price [Member]                      
Warrants and Rights Outstanding, Measurement Input (in dollars per share) | $ / shares                     53.20
Warrant In Connection with Oxford Finance Loan Agreement [Member] | Measurement Input, Expected Term [Member]                      
Warrants and Rights Outstanding, Measurement Input (in dollars per share) | yr                     10
Warrant In Connection with Oxford Finance Loan Agreement [Member] | Measurement Input, Price Volatility [Member]                      
Warrants and Rights Outstanding, Measurement Input (in dollars per share)                     0.8022
Warrant In Connection with Oxford Finance Loan Agreement [Member] | Measurement Input, Risk Free Interest Rate [Member]                      
Warrants and Rights Outstanding, Measurement Input (in dollars per share)                     0.0222
Warrant In Connection with Oxford Finance Loan Agreement [Member] | Measurement Input, Expected Dividend Rate [Member]                      
Warrants and Rights Outstanding, Measurement Input (in dollars per share)                     0
Warrant In Connection with Oxford Finance Loan Agreement [Member] | Measurement Input, Exercise Price [Member]                      
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares                     $ 56.60
December 2022 Financing [Member]                      
Stock Issued During Period, Shares, New Issues (in shares) | shares   748,744                  
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares   $ 0.001                  
Equity Offering, Price Per Unit (in dollars per share) | $ / shares $ 2.22625                    
Proceeds from Issuance or Sale of Equity, Total           $ 7,500,000          
Payments of Stock Issuance Costs           1,700,000          
Equity Issuance Costs, Modification of Warrants           $ 800,000          
Proceeds from Issuance or Sale of Equity, After Warrant Adjustment $ 400,000                    
Proceeds from Issuance of Common Stock 95,000                    
Proceeds from Issuance or Sale of Equity, Net $ 6,600,000                    
Securities Purchase Agreement [Member]                      
Proceeds from Issuance or Sale of Equity, Total     $ 300,000                
Proceeds from Issuance or Sale of Equity, Net     $ 200,000                
2021 Registered Direct Offering [Member]                      
Stock Issued During Period, Shares, New Issues (in shares) | shares       875,000              
Proceeds from Issuance or Sale of Equity, Total       $ 14,000,000.0 $ 14,000,000.0            
Proceeds from Issuance of Common Stock             $ 7,528,000 0      
Proceeds from Issuance of Warrants             $ 0 $ 13,918,000      
2021 Registered Direct Offering [Member] | Measurement Input, Risk Free Interest Rate [Member]                      
Proceeds from Issuance or Sale of Equity, Total         14,000,000.0            
Proceeds from Issuance of Common Stock         $ 8,400,000            
2021 Registered Direct Offering [Member] | November 2021 Financing Warrants [Member]                      
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares       875,000