Quarterly report pursuant to Section 13 or 15(d)

Note 11 - Common Stock (Details Textual)

v3.20.2
Note 11 - Common Stock (Details Textual)
1 Months Ended 3 Months Ended 6 Months Ended 11 Months Ended
Jun. 09, 2020
USD ($)
$ / shares
shares
Jun. 08, 2020
USD ($)
Apr. 20, 2020
USD ($)
$ / shares
shares
Apr. 16, 2020
USD ($)
shares
Jun. 30, 2020
USD ($)
$ / shares
shares
May 31, 2020
USD ($)
shares
Mar. 31, 2020
USD ($)
shares
Feb. 29, 2020
USD ($)
shares
Nov. 30, 2019
USD ($)
$ / shares
shares
Jun. 30, 2020
USD ($)
$ / shares
shares
Mar. 31, 2020
USD ($)
shares
Jun. 30, 2019
USD ($)
shares
Mar. 31, 2019
USD ($)
shares
Jun. 30, 2020
USD ($)
$ / shares
shares
Jun. 30, 2019
USD ($)
shares
Nov. 30, 2019
$ / shares
shares
Apr. 15, 2020
$ / shares
Dec. 31, 2019
$ / shares
shares
Nov. 26, 2019
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)         23,583,290         23,583,290       23,583,290              
Stock Issued During Period, Share, Restricted Common Shares (in shares)         34,531   28,313                            
Stock Issued During Period, Value, Restricted Common Shares | $         $ 25,000   $ 24,000     $ 25,000 $ 24,000   $ 25,000                
Proceeds from Warrant Exercises | $                           $ 4,800,000            
Fair Value Adjustment of Warrants | $                   1,838,000     1,838,000            
Payments of Warrant Issuance Costs | $     $ 326,000                     326,000            
Amortization of Debt Discount (Premium) | $                   1,000   $ 119,000   2,000 $ 202,000            
Debt Instrument, Unamortized Discount, Total | $         10,000         $ 10,000       $ 10,000              
Class of Warrant or Right Number of Securities Called by Warrants or Rights Cancelled In Period (in shares)                   0   0   0 0            
Class Of Warrant Or Right, Number Of Securities Called By Warrants Or Rights Expired In Period (in shares)                   215   0   215 0            
The 2017 Loan Agreement [Member]                                          
Debt Issuance Costs, Net, Total | $         790,000         $ 790,000       $ 790,000              
Debt Instrument, Unamortized Discount, Total | $         $ 10,000         $ 10,000       $ 10,000              
Series B Convertible Preferred Stock Into Common Stock [Member] | Minimum [Member]                                          
Conversion of Stock, Conversion Rate (in dollars per share) | $ / shares                                       $ 1.53  
Series B Convertible Preferred Stock Into Common Stock [Member] | Maximum [Member]                                          
Conversion of Stock, Conversion Rate (in dollars per share) | $ / shares                                       $ 1.836  
Series A Preferred Stock [Member]                                          
Convertible Preferred Stock, Shares Issued upon Conversion (in shares)         1       1 1       1   1          
Preferred Stock, Shares Outstanding, Ending Balance (in shares)         0         0       0       1,852,173      
Series B Preferred Stock [Member]                                          
Convertible Preferred Stock, Shares Issued upon Conversion (in shares)         22,016,179         22,016,179       22,016,179              
Preferred Stock, Shares Outstanding, Ending Balance (in shares)         33,685         33,685       33,685       31,678 [1]      
Conversion of Stock, Conversion Rate (in dollars per share) | $ / shares         $ 1.53         $ 1.53       $ 1.53              
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                 $ 1.55             $ 1.55          
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)         1,540,829       7,419,353 1,540,829       1,540,829   7,419,353          
Stock Issued During Period, Shares, Warrant Exercises (in shares)       4,820,584 27,601 4,099   1,026,240                          
Proceeds from Warrant Exercises | $         $ 17,000 $ 2,500   $ 1,591,000                          
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                 $ 1.55             $ 1.55          
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)         7,080,390       7,419,353 7,080,390       7,080,390   7,419,353          
Stock Issued During Period, Shares, Warrant Exercises (in shares)       242,790 50,700     45,473                          
Proceeds from Warrant Exercises | $         $ 31,000     $ 70,000                          
Series A and Series B Warrants [Member]                                          
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares                                 $ 0.61 $ 1.55      
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)     4,820,584                                    
Series B-2 Warrants [Member]                                          
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)     242,790                                    
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     $ 0.6371                                    
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     0.841                                    
Series A-2 and Series B-2 Warrants [Member] | Measurement Input, Risk Free Interest Rate [Member]                                          
Warrants and Rights Outstanding, Measurement Input     0.0035                                    
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]                                          
Warrants and Rights Outstanding, Term (Year)                                       5 years  
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)                                     9,893,776 9,893,776  
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 and Rights Outstanding | $         $ 3,502,000         $ 3,502,000       $ 3,502,000           $ 3,502,000  
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                                         $ 950
Warrants and Rights Outstanding, Term (Year)                                         10 years
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)                                         2,220
Warrants and Rights Outstanding | $                                         $ 940,000
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                 $ 1.55             $ 1.55          
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                 $ 1.55             $ 1.55          
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                 $ 1.55             $ 1.55          
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                 $ 1.55             $ 1.55          
Warrants and Rights Outstanding, Term (Year)                 5 years             5 years          
Common Stock [Member]                                          
Stock Issued During Period, Shares, New Issues (in shares)                   525,000                      
Stock Issued During Period, Share, Restricted Common Shares (in shares)                   34,531 28,313   274                
Stock Issued During Period, Value, Restricted Common Shares | $                                    
Common Stock [Member] | Series A Warrants [Member]                                          
Stock Issued During Period, Shares, Warrant Exercises (in shares)                   4,852,284 1,026,240                    
Common Stock [Member] | Series B Warrants [Member]                                          
Stock Issued During Period, Shares, Warrant Exercises (in shares)                   293,490 45,473                    
Purchase Agreement with LPC [Member]                                          
Maximum Amount of Shares Issuable | $ $ 10,000,000 $ 10,000,000                                      
Stock Purchase Agreement Duration Period (Month) 2 years 180 days 2 years 180 days                                      
Stock Issued During Period, Shares, New Issues (in shares) 525,000                                        
Shares Issued, Price Per Share (in dollars per share) | $ / shares $ 0.65                                        
Maximum Number of Shares Issuable on Any Business Day Selected by The Company (in shares) 250,000                                        
Maximum Number of Shares Issuable on Regular Purchase, Closing Sale Price Not Below $1.00 (in shares) 300,000                                        
Maximum Number of Shares Issuable on Regular Purchase, Closing Sale Price Not Below $2.00 (in shares) 500,000                                        
Maximum Number of Shares Issuable Any single Regular Purchase (in shares) 1,000,000                                        
Payments of Stock Issuance Costs | $ $ 452,000                         452,000            
Purchase Agreement with LPC [Member] | Commitment Fee [Member]                                          
Payments of Stock Issuance Costs | $ $ 325,000                                        
November 2019 Offering [Member]                                          
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                        
November 2019 Offering [Member] | Series A Preferred Stock [Member]                                          
Stock Issued During Period, Shares, New Issues (in shares)                 5,473,410                        
November 2019 Offering [Member] | Series B Preferred Stock [Member]                                          
Stock Issued During Period, Shares, New Issues (in shares)                               5,473,410          
November 2019 Offering [Member] | Class A Units [Member]                                          
Shares Issued, Price Per Share (in dollars per share) | $ / shares                 $ 1.55             $ 1.55          
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                 $ 1.55             $ 1.55          
Series A Convertible Preferred Stock Per Unit (in shares)                 1             1          
November 2019 Offering [Member] | Common Stock [Member]                                          
Stock Issued During Period, Shares, New Issues (in shares)                 1,945,943             1,945,943          
[1] The condensed consolidated balance sheet as of December 31, 2019 has been derived from the audited consolidated financial statements as of that date.