v3.23.2
Note 14 - Stockholders' Equity (Deficit) (Details Textual)
 1 Months Ended 6 Months Ended 12 Months Ended
Dec. 29, 2022
USD ($)
$ / shares
Dec. 27, 2022
$ / shares
shares
Oct. 25, 2022
$ / shares
Oct. 12, 2022
USD ($)
shares
Sep. 23, 2022
Aug. 03, 2022
USD ($)
$ / shares
shares
Nov. 17, 2021
USD ($)
$ / shares
shares
Nov. 15, 2021
USD ($)
$ / shares
shares
Jan. 27, 2021
$ / shares
shares
Jan. 27, 2021
USD ($)
$ / shares
shares
Jan. 22, 2021
$ / shares
shares
May 09, 2019
USD ($)
Jun. 21, 2016
USD ($)
Dec. 31, 2022
USD ($)
$ / shares
shares
Jan. 31, 2011
shares
Dec. 31, 2022
USD ($)
$ / shares
shares
Dec. 31, 2022
USD ($)
$ / shares
shares
Dec. 31, 2021
USD ($)
$ / shares
shares
Jun. 17, 2021
shares
Jun. 16, 2020
shares
Dec. 31, 2011
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares     $ 0.001                     $ 0.001   $ 0.001 $ 0.001 $ 0.001      
Stock Issued During Period, Value, New Issues                                 $ 790,000 $ 44,716,000      
Share Price (in dollars per share) | $ / shares             $ 14.92                            
Common Stock, Value, Issued, Ending Balance [1]                           $ 8,000   $ 8,000 8,000 7,000 [2]      
Warrants and Rights Outstanding                           $ 7,098,000   $ 7,098,000 $ 7,098,000 $ 0      
Employee Stock Purchase Plan, Shares Issued, Weighted Average Fair Value (in dollars per share) | $ / shares                                 $ 6.82 $ 20.23      
Restricted Stock Units (RSUs) [Member]                                          
Share-Based Payment Arrangement, Shares Withheld for Tax Withholding Obligation (in shares) | shares                               0          
2011 Equity Incentive Plan [Member]                                          
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other Than Options, Outstanding (in shares) | shares                             100,000            
Stock Option Plan Option Reserve Annual Increase as Percentage of Outstanding Shares Allowed                                         4.00%
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares) | shares                                       300,000  
The 2020 Equity Incentive Plan [Member]                                          
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares) | shares                                     200,000    
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares) | shares                           342,827   342,827 342,827        
Amended ESPP [Member]                                          
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares) | shares                                     300,000    
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares) | shares                           211,876   211,876 211,876        
Employee Stock Purchase Plan (ESPP) [Member]                                          
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares) | shares                           10,941   10,941 10,941     200,000  
Securities Purchase Agreement [Member]                                          
Proceeds from Issuance or Sale of Equity, Total           $ 300,000                              
Proceeds from Issuance or Sale of Equity, Net           $ 200,000                              
December 2022 Financing [Member]                                          
Stock Issued During Period, Shares, New Issues (in shares) | shares   748,744                                      
Proceeds from Issuance or Sale of Equity, Total                           $ 7,500,000              
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, Net $ 6,600,000                                        
Proceeds from Issuance of Common Stock $ 95,000                                        
Private Placement [Member] | Armistice Capital and Rock Springs Capital [Member]                                          
Stock Issued During Period, Shares, New Issues (in shares) | shares                 108,750 833,750 725,000                    
Proceeds from Issuance of Common Stock                   $ 28,900,000                      
Shares Issued, Price Per Share (in dollars per share) | $ / shares                 $ 35.25 $ 35.25 $ 35.25                    
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      
Shares Issued, Price Per Share (in dollars per share) | $ / shares             $ 16.00                            
Net Proceeds from Issuance of Common Stock and Exercise of Warrants             $ 13,900,000                            
Stock Issued During Period, Value, New Issues             13,100,000                            
Common Stock, Value, Issued, Ending Balance             $ 8,400,000                            
ATM Agreement [Member]                                          
Stock Issued During Period, Shares, New Issues (in shares) | shares                                 0.1 200,000      
Proceeds from Issuance of Common Stock                                 $ 458,000 $ 7,474,000      
Aggregate Offering Price, Maximum                       $ 80,000,000.0 $ 40,000,000.0       $ 35,600,000        
Aggregate Offering Price, Increase During Period                       $ 40,000,000.0                  
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 $ 2.07        
Proceeds from Issuance or Sale of Equity, Net           $ 110,000                              
Warrants and Rights Outstanding           $ 300,000                              
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                                        
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                                        
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   125,000 125,000        
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares             $ 20.00 $ 20.00           $ 20.00   $ 20.00 $ 20.00        
Warrants and Rights Outstanding             $ 5,600,000 $ 8,600,000                          
November 2021 Financing Warrants [Member] | 2021 Registered Direct Offering [Member]                                          
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares             875,000                            
Redeemable Convertible Preferred Stock [Member]                                          
Stock Issued During Period, Shares, New Issues (in shares) | shares           3,000                              
Preferred Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares           $ 0.001                              
Preferred Stock Stated Value Per Share (in dollars per share) | $ / shares           $ 100                              
Temporary Equity, Carrying Amount, Attributable to Parent           $ 100,000                              
Preferred Stock, Redemption Price Per Share (in dollars per share) | $ / shares           $ 3.70                              
Preferred Stock, Company Option to Convert, Percentage of Stated Value       105.00%   105.00%                              
Preferred Stock, Purchaser Option to Convert, Percentage of Stated Value           110.00%                              
Dividends, Preferred Stock, Total           $ 200,000                              
Reverse Stock Split, Preferred Stock Votes per Share           1,000,000                              
Preferred Stock, Shares Outstanding, Ending Balance (in shares) | shares       3,000                                  
Preferred Stock, Redemption Amount       $ 300,000                                  
Preferred Stock, Elimination of Designation, Shares (in shares) | shares       3,000                                  
Proceeds from Issuance or Sale of Equity, Net           $ 129,000                              
Stock Issued During Period, Value, New Issues                                 $ 110,000        
Maximum [Member] | 2011 Equity Incentive Plan [Member]                                          
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares to be Added (in shares) | shares                                       700,000  
Reverse Stock Split [Member]                                          
Stockholders' Equity Note, Stock Split, Conversion Ratio     20                                    
Reverse Stock Split [Member] | Maximum [Member]                                          
Stockholders' Equity Note, Stock Split, Conversion Ratio         30                                
[1] Adjusted to give retroactive effect to a 1-for-20 reverse stock split effective as of 5:01 p.m. Eastern Time on October 25, 2022.
[2] The condensed consolidated balance sheet as of December 31, 2020 has been derived from the audited financial statements as of that date included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020.