Annual report pursuant to Section 13 and 15(d)

Note 12 - Common Stock (Details Textual)

v3.20.4
Note 12 - Common Stock (Details Textual)
1 Months Ended 3 Months Ended 11 Months Ended 12 Months Ended
Jun. 09, 2020
USD ($)
$ / shares
shares
Jun. 08, 2020
USD ($)
Apr. 20, 2020
USD ($)
$ / shares
shares
Apr. 16, 2020
USD ($)
shares
Sep. 30, 2020
USD ($)
shares
Aug. 31, 2020
USD ($)
shares
Jun. 30, 2020
USD ($)
shares
May 31, 2020
USD ($)
shares
Mar. 31, 2020
USD ($)
shares
Feb. 29, 2020
USD ($)
shares
Dec. 31, 2019
USD ($)
$ / shares
shares
Nov. 30, 2019
USD ($)
$ / shares
shares
Oct. 31, 2019
USD ($)
shares
Aug. 31, 2019
USD ($)
Mar. 31, 2019
USD ($)
shares
Nov. 30, 2019
USD ($)
$ / shares
shares
Dec. 31, 2020
USD ($)
shares
Dec. 31, 2019
USD ($)
$ / shares
shares
Dec. 16, 2020
shares
Apr. 15, 2020
$ / shares
Nov. 12, 2019
USD ($)
$ / shares
shares
May 22, 2017
USD ($)
$ / shares
shares
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)                     2,473,785             2,473,785        
Stock Issued During Period, Share, Restricted Common Shares (in shares)         4,709   3,453   2,832   3,068   774   28              
Stock Issued During Period, Value, Restricted Common Shares | $         $ 25,000   $ 25,000   $ 24,000   $ 25,000   $ 25,000   $ 25,000   $ 74,000 $ 75,000        
Warrants and Rights Outstanding | $                     $ 3,502,000             3,502,000        
Proceeds from Warrant Exercises | $                                 8,407,000        
Fair Value Adjustment of Warrants | $                                 1,838,000        
Payments of Warrant Issuance Costs | $     $ 334,000                           334,000        
Amortization of Debt Discount (Premium) | $                                 3,000 $ 352,000        
Debt Instrument, Unamortized Discount, Total | $                                 $ 9,000          
Class of Warrants or Rights, Exercises in Period (in shares)                                 1,209,000 0        
Class of Warrant or Right Number of Securities Called by Warrants or Rights Cancelled In Period (in shares)                                 0 0        
Class Of Warrant Or Right, Number Of Securities Called By Warrants Or Rights Expired In Period (in shares)                                 42,404 140        
The 2017 Loan Agreement [Member]                                            
Debt Issuance Costs, Net, Total | $                                 $ 790,000          
Debt Instrument, Unamortized Discount, Total | $                                 $ 9,000          
Series B Convertible Preferred Stock Into Common Stock [Member] | Minimum [Member]                                            
Conversion of Stock, Conversion Rate (in dollars per share) | $ / shares                                         $ 15.30  
Series B Convertible Preferred Stock Into Common Stock [Member] | Maximum [Member]                                            
Conversion of Stock, Conversion Rate (in dollars per share) | $ / shares                                         $ 18.36  
Series A Preferred Stock [Member]                                            
Stock Issued During Period, Shares, New Issues (in shares)                       547,345                    
Convertible Preferred Stock, Shares Issued upon Conversion (in shares)                     1 1       1 1 1        
Preferred Stock, Shares Outstanding, Ending Balance (in shares)                     185,218           0 185,218 0      
Series A Warrants [Member]                                            
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)                       1       1            
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares                     $ 18.36 $ 15.50       $ 15.50   $ 18.36        
Warrants and Rights Outstanding, Term (Year)                       1 year       1 year            
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)                     989,379 741,939       741,939   989,379        
Warrants and Rights Outstanding | $                       $ 1,210,000       $ 1,210,000            
Stock Issued During Period, Shares, Warrant Exercises (in shares)       482,059   111,704 2,761 410   102,626                        
Proceeds from Warrant Exercises | $           $ 681,000 $ 17,000 $ 2,000   $ 1,591,000                        
Class of Warrant or Right, Outstanding (in shares)                                 0          
Series A Warrants [Member] | Measurement Input, Expected Dividend Rate [Member]                                            
Warrants and Rights Outstanding, Measurement Input                       0       0            
Series A Warrants [Member] | Measurement Input, Price Volatility [Member]                                            
Warrants and Rights Outstanding, Measurement Input                       91.1       91.1            
Series A Warrants [Member] | Measurement Input, Risk Free Interest Rate [Member]                                            
Warrants and Rights Outstanding, Measurement Input                       1.59       1.59            
Series A Warrants [Member] | Measurement Input, Expected Term [Member]                                            
Warrants and Rights Outstanding, Measurement Input                       1       1            
Series B Warrants [Member]                                            
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)                       1       1            
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares                     $ 15.50 $ 15.50       $ 15.50   $ 15.50        
Warrants and Rights Outstanding, Term (Year)                       5 years       5 years            
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)                     741,940 741,939       741,939 325,632 741,940        
Warrants and Rights Outstanding | $                       $ 2,871,000       $ 2,871,000            
Stock Issued During Period, Shares, Warrant Exercises (in shares)       24,279 1,500 380,913 5,070     4,548                        
Proceeds from Warrant Exercises | $         $ 9,000 $ 2,324,000 $ 31,000     $ 70,000                        
Class of Warrant or Right, Outstanding (in shares)                                 325,632          
Series B Warrants [Member] | Measurement Input, Expected Dividend Rate [Member]                                            
Warrants and Rights Outstanding, Measurement Input                       0       0            
Series B Warrants [Member] | Measurement Input, Price Volatility [Member]                                            
Warrants and Rights Outstanding, Measurement Input                       0.688       0.688            
Series B Warrants [Member] | Measurement Input, Risk Free Interest Rate [Member]                                            
Warrants and Rights Outstanding, Measurement Input                       0.0158       0.0158            
Series B Warrants [Member] | Measurement Input, Expected Term [Member]                                            
Warrants and Rights Outstanding, Measurement Input                       5       5            
Series A and Series B Warrants [Member]                                            
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares                     $ 15.50             $ 15.50   $ 6.10    
Warrants and Rights Outstanding | $                       $ 4,081,000       $ 4,081,000            
Proceeds from Warrant Exercises | $       $ 3,089,000                                    
Series A-2 Warrants [Member]                                            
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)     482,059                           392,830          
Stock Issued During Period, Shares, Warrant Exercises (in shares)           89,230                     392,830          
Proceeds from Warrant Exercises | $           $ 568,000                                
Series B-2 Warrants [Member]                                            
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)     24,279                           20,380          
Stock Issued During Period, Shares, Warrant Exercises (in shares)           3,899                     20,380          
Proceeds from Warrant Exercises | $           $ 25,000                                
Series A-2 and Series B-2 Warrants [Member]                                            
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares     $ 6.371                                      
Warrants and Rights Outstanding, Term (Year)     5 years                                      
Class of Warrant or Right, Outstanding (in shares)     1,838,000                                      
Series A-2 and Series B-2 Warrants [Member] | Measurement Input, Expected Dividend Rate [Member]                                            
Warrants and Rights Outstanding, Measurement Input     0                                      
Series A-2 and Series B-2 Warrants [Member] | Measurement Input, Price Volatility [Member]                                            
Warrants and Rights Outstanding, Measurement Input     0.00841                                      
Series A-2 and Series B-2 Warrants [Member] | Measurement Input, Risk Free Interest Rate [Member]                                            
Warrants and Rights Outstanding, Measurement Input     0.35                                      
Series A-2 and Series B-2 Warrants [Member] | Measurement Input, Expected Term [Member]                                            
Warrants and Rights Outstanding, Measurement Input     5                                      
Warrants Issued Upon Conversion of Term Loan with CRG [Member]                                            
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares                     $ 15.50             $ 15.50        
Warrants and Rights Outstanding, Term (Year)                                         5 years  
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)                     741,940             741,940     989,379  
Warrants and Rights Outstanding | $                                         $ 3,502,000  
Class of Warrants or Rights, Outstanding, Percentage of Common Stock                                         15.00%  
Class of Warrants and Rights Outstanding, Exercise Price Percentage of Conversion Rate                                         120.00%  
Warrants Issued Upon Conversion of Term Loan with CRG [Member] | Measurement Input, Expected Dividend Rate [Member]                                            
Warrants and Rights Outstanding, Measurement Input                                         0  
Warrants Issued Upon Conversion of Term Loan with CRG [Member] | Measurement Input, Price Volatility [Member]                                            
Warrants and Rights Outstanding, Measurement Input                                         0.688  
Warrants Issued Upon Conversion of Term Loan with CRG [Member] | Measurement Input, Risk Free Interest Rate [Member]                                            
Warrants and Rights Outstanding, Measurement Input                                         0.0158  
Warrants Issued Upon Conversion of Term Loan with CRG [Member] | Measurement Input, Expected Term [Member]                                            
Warrants and Rights Outstanding, Measurement Input                                         5  
May 2017 Issuance Related to 2017 Loan Agreement [Member]                                            
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares                     $ 9,500             $ 9,500       $ 9,500
Warrants and Rights Outstanding, Term (Year)                                           10 years
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)                     223             223       223
Warrants and Rights Outstanding | $                                           $ 940,000
May 2017 Issuance Related to 2017 Loan Agreement [Member] | Measurement Input, Expected Dividend Rate [Member]                                            
Warrants and Rights Outstanding, Measurement Input                                           0
May 2017 Issuance Related to 2017 Loan Agreement [Member] | Measurement Input, Price Volatility [Member]                                            
Warrants and Rights Outstanding, Measurement Input                                           55.1
May 2017 Issuance Related to 2017 Loan Agreement [Member] | Measurement Input, Risk Free Interest Rate [Member]                                            
Warrants and Rights Outstanding, Measurement Input                                           2.25
May 2017 Issuance Related to 2017 Loan Agreement [Member] | Measurement Input, Expected Term [Member]                                            
Warrants and Rights Outstanding, Measurement Input                                           10
Class A Units [Member] | Series A Warrants [Member]                                            
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)                       1       1            
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares                       $ 15.50       $ 15.50            
Warrants and Rights Outstanding, Term (Year)                       1 year       1 year            
Class A Units [Member] | Series B Warrants [Member]                                            
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)                       1       1            
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares                       $ 15.50       $ 15.50            
Warrants and Rights Outstanding, Term (Year)                       5 years       5 years            
Class B Units [Member] | Series A Warrants [Member]                                            
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)                       1       1            
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares                       $ 15.50       $ 15.50            
Warrants and Rights Outstanding, Term (Year)                       1 year       1 year            
Class B Units [Member] | Series B Warrants [Member]                                            
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)                       1       1            
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares                       $ 15.50       $ 15.50            
Warrants and Rights Outstanding, Term (Year)                       5 years       5 years            
Common Stock [Member]                                            
Stock Issued During Period, Shares, New Issues (in shares)                                 52,500          
Stock Issued During Period, Share, Restricted Common Shares (in shares)                                 10,995 3,869        
Stock Issued During Period, Value, Restricted Common Shares | $                                        
Common Stock [Member] | Series A and Series B Warrants [Member]                                            
Stock Issued During Period, Shares, Warrant Exercises (in shares)                                 1,115,863          
Common Stock [Member] | Series A-2 and Series B-2 Warrants [Member]                                            
Stock Issued During Period, Shares, Warrant Exercises (in shares)                                 93,129          
Purchase Agreement with LPC [Member]                                            
Maximum Amount of Shares Issuable | $   $ 10,000,000                                        
Stock Purchase Agreement Duration Period (Month)   2 years 180 days                                        
Stock Issued During Period, Shares, New Issues (in shares) 52,500                                          
Shares Issued, Price Per Share (in dollars per share) | $ / shares $ 6.50                                          
Maximum Number of Shares Issuable on Any Business Day Selected by The Company (in shares) 25,000                                          
Maximum Number of Shares Issuable on Regular Purchase, Closing Sale Price Not Below $10.00 (in shares) 30,000                                          
Maximum Number of Shares Issuable on Regular Purchase, Closing Sale Price Not Below $20.00 (in shares) 50,000                                          
Maximum Number of Shares Issuable Any single Regular Purchase (in shares) 1,000,000                                          
Payments of Stock Issuance Costs | $ $ 494,000                               $ 494,000        
Purchase Agreement with LPC [Member] | Commitment Fee [Member]                                            
Payments of Stock Issuance Costs | $ $ 325,000                                          
November 2019 Offering [Member]                                            
Shares Issued, Price Per Share (in dollars per share) | $ / shares                       $ 15.50       $ 15.50            
Payments of Stock Issuance Costs | $                                 $ 33,000        
Proceeds from Issuance or Sale of Equity, Total | $                       $ 11,500,000                    
Proceeds From Issuance of Common Stock, Net | $                       $ 9,922,000                    
Common Shares Per Unit (in shares)                       1       1            
November 2019 Offering [Member] | Series A Preferred Stock [Member]                                            
Stock Issued During Period, Shares, New Issues (in shares)                       547,345       547,341            
November 2019 Offering [Member] | Class A Units [Member]                                            
Shares Issued, Price Per Share (in dollars per share) | $ / shares                       $ 15.50       $ 15.50            
Common Shares Per Unit (in shares)                       1       1            
November 2019 Offering [Member] | Class B Units [Member]                                            
Shares Issued, Price Per Share (in dollars per share) | $ / shares                       $ 15.50       $ 15.50            
Series A Convertible Preferred Stock Per Unit (in shares)                       1       1            
November 2019 Offering [Member] | Class B Units [Member] | Series A Preferred Stock [Member]                                            
Convertible Preferred Stock, Shares Issued upon Conversion (in shares)                       1       1            
November 2019 Offering [Member] | Common Stock [Member]                                            
Stock Issued During Period, Shares, New Issues (in shares)                       194,595       194,595   194,595        
August 2019 ATM Facility [Member]                                            
Stock Issued During Period, Shares, New Issues (in shares)                                   100,423        
Proceeds From Issuance of Common Stock, Net | $                                   $ 6,322,000        
Aggregate Offering Price | $                           $ 6,760,000                
Common Stock, Shares, Remaining Shares to be Issued (in shares)                     0             0        
August 2019 ATM Facility [Member] | Common Stock [Member]                                            
Stock Issued During Period, Shares, New Issues (in shares)                                   100,418        
November 2017 ATM Facility [Member]                                            
Stock Issued During Period, Shares, New Issues (in shares)                                   0        
Aggregate Offering Price | $                           $ 25,000,000