Annual report pursuant to Section 13 and 15(d)

Note 9 - Stockholders' Equity (Details Textual)

v3.23.1
Note 9 - Stockholders' Equity (Details Textual)
$ / shares in Units, $ in Thousands
1 Months Ended 12 Months Ended
Jun. 22, 2022
shares
Jun. 25, 2021
shares
May 20, 2021
$ / shares
shares
Apr. 01, 2020
shares
Jan. 30, 2019
shares
Nov. 30, 2022
USD ($)
Aug. 31, 2021
USD ($)
$ / shares
Nov. 30, 2019
USD ($)
$ / shares
shares
Aug. 31, 2019
USD ($)
Jun. 30, 2016
USD ($)
$ / shares
shares
Dec. 31, 2022
USD ($)
$ / shares
shares
Dec. 31, 2021
USD ($)
$ / shares
shares
Common Stock, Shares Authorized (in shares)                     300,000,000 300,000,000
Common Stock, Shares, Issued (in shares)                     74,519,103 72,222,661
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares                     $ 0.001 $ 0.001
Preferred Stock, Shares Authorized (in shares)                     10,000,000 10,000,000
Preferred Stock, Shares Issued (in shares)                     15,617 15,617
Preferred Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares                     $ 0.001 $ 0.001
Preferred Stock, Shares Outstanding, Ending Balance (in shares)                     15,617 15,617
Proceeds from Issuance of Private Placement | $                     $ 0 $ 18,913
Proceeds from Issuance of Common Stock | $                 $ 50,000   $ 6,922 $ 38,188
Common Stock, Shares, Outstanding, Ending Balance (in shares)                     74,519,103 72,222,661
Jefferies L L C [Member]                        
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares             $ 0.001          
Conversion of Common Stock into Series E Preferred Stock [Member]                        
Conversion of Stock, Shares Converted (in shares)     5,000,000                  
Conversion of Stock, Shares Issued (in shares)     5,000                  
Employee Director And Consultant Equity Incentive Plan2020 [Member]                        
Sale of Stock, Number of Shares Issued in Transaction (in shares)       3,000                
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized (in shares) 3,000,000 2,250,000   3,000,000                
Securities Purchase Agreement [Member]                        
Preferred Stock, Shares Issued (in shares)                   4,963    
Partners' Capital Account, Units, Sold in Private Placement (in shares)                   8,188,804    
Shares Issued, Price Per Share (in dollars per share) | $ / shares                   $ 2.015    
Proceeds from Issuance of Private Placement | $                   $ 16,500    
Proceeds From Issuance Of Private Placement Net | $                   $ 15,300    
Sale of Stock, Number of Shares Issued in Transaction (in shares)                   3,225,804    
At the Market Offering [Member]                        
Sale of Stock, Number of Shares Issued in Transaction (in shares)                     2,100,000 8,200,000
At the Market Offering [Member] | Jefferies L L C [Member]                        
Sale of Stock, Price Per Share (in dollars per share) | $ / shares                     $ 3.46 $ 4.85
Sale of Stock, Authorized Amount | $           $ 75,000 $ 50,000          
Sale of Stock, Consideration Received on Transaction | $                     $ 7,200 $ 39,700
Common Stock [Member]                        
Number Of Votes Per Share                     1  
Common Stock [Member] | Stock Exchange Shares from Existing Shareholders [Member]                        
Sale of Stock, Number of Shares Issued in Transaction (in shares)         5,000,000              
Preferred Stock [Member] | Preferred Share Exchange [Member]                        
Sale of Stock, Number of Shares Issued in Transaction (in shares)         5,000              
Series A Preferred Stock [Member]                        
Preferred Stock, Shares Issued (in shares)                     85 85
Preferred Stock, Shares Outstanding, Ending Balance (in shares)                     85 85
Series B Preferred Stock [Member]                        
Preferred Stock, Shares Issued (in shares)                     4,026 4,026
Preferred Stock, Shares Outstanding, Ending Balance (in shares)                     4,026 4,026
Series C Preferred Stock [Member]                        
Preferred Stock, Shares Issued (in shares)                     3,506 3,506
Preferred Stock, Shares Outstanding, Ending Balance (in shares)                     3,506 3,506
Series C Preferred Stock [Member] | Preferred Share Exchange [Member]                        
Sale of Stock, Price Per Share (in dollars per share) | $ / shares               $ 3.43        
Debt Instrument, Convertible, Beneficial Conversion Feature | $               $ 2,800        
Series C Preferred Stock [Member] | Private Placement [Member]                        
Convertible Preferred Stock, Shares Issued upon Conversion (in shares)               0.001        
Proceeds From Issuance Of Private Placement Net | $               $ 31,000        
Sale of Stock, Number of Shares Issued in Transaction (in shares)               9,014,960        
Sale of Stock, Price Per Share (in dollars per share) | $ / shares               $ 3.55        
Sale of Stock, Consideration Received Per Transaction | $               $ 32,000        
Stock Issued During Period, Shares, Conversion of Units (in shares)               1        
Sale of Stock, Number of Warrants, Per Unit (in shares)               1        
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)               1        
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares               $ 7.10        
Convertible Preferred Stock, Weighted Average Stock Price, Percent               3.00%        
Series C Preferred Stock [Member] | Private Placement [Member] | Maximum [Member]                        
Warrants and Rights Outstanding, Term (Year)               5 years        
Series D Preferred Stock [Member]                        
Preferred Stock, Shares Issued (in shares)                     3,000 3,000
Preferred Stock, Shares Outstanding, Ending Balance (in shares)                     3,000 3,000
Series E Preferred Stock [Member]                        
Preferred Stock, Shares Issued (in shares)                     5,000 5,000
Preferred Stock, Shares Outstanding, Ending Balance (in shares)                     5,000 5,000
Series A Through E [Member] | Preferred Stock [Member]                        
Preferred Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares     $ 0.001                  
Convertible Preferred Stock, Shares Issued upon Conversion (in shares)     1,000                  
Convertible Preferred Stock, Common Stock Ownership Limit, Percent     9.99%                  
Convertible Preferred Stock, Beneficial Ownership Limitation, Percent     19.99%                  
Convertible Preferred Stock, Beneficial Ownership Limitation, Notice Period Before Increase (Year)     61 years