Quarterly report pursuant to Section 13 or 15(d)

Note 10 - Common Stock (Details Textual)

v3.20.1
Note 10 - Common Stock (Details Textual)
1 Months Ended 3 Months Ended 11 Months Ended 12 Months Ended
Aug. 16, 2019
USD ($)
Mar. 31, 2020
USD ($)
$ / shares
shares
Feb. 29, 2020
USD ($)
shares
Jan. 31, 2020
shares
Dec. 31, 2019
USD ($)
shares
Nov. 30, 2019
USD ($)
$ / shares
shares
Oct. 31, 2019
USD ($)
Aug. 31, 2019
USD ($)
Mar. 31, 2019
USD ($)
Mar. 31, 2020
USD ($)
$ / shares
shares
Sep. 30, 2019
USD ($)
shares
Mar. 31, 2019
USD ($)
shares
Nov. 30, 2019
USD ($)
$ / shares
shares
Dec. 31, 2019
USD ($)
shares
Nov. 26, 2019
USD ($)
shares
Nov. 12, 2019
USD ($)
$ / shares
shares
May 22, 2017
USD ($)
yr
$ / shares
shares
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)   23,665,905               23,665,905              
Proceeds from Warrant Exercises | $                   $ 1,661,000            
Stock Issued During Period, Value, Restricted Stock Award, Gross | $                       25,000          
Amortization of Debt Discount (Premium) | $                   1,000   $ 83,000          
Debt Instrument, Unamortized Discount, Total | $   $ 11,000               $ 11,000              
Class of Warrants or Rights, Exercises in Period (in shares)                   0   0          
Class of Warrant or Right Number of Securities Called by Warrants or Rights Cancelled In Period (in shares)                   0   0          
Share-based Payment Arrangement, Expense | $                   $ 710,000   $ 496,000          
Class of Warrant or Right, Issued During Period (in shares)                   0   0          
The 2017 Loan Agreement [Member]                                  
Debt Issuance Costs, Net, Total | $   790,000               $ 790,000              
Restricted Stock [Member]                                  
Proceeds From Issuance of Common Stock, Net | $   28,313     $ 30,675   $ 7,740   $ 274                
Stock Issued During Period, Value, Restricted Stock Award, Gross | $   $ 24,000     $ 25,000   $ 25,000   $ 25,000                
Series A Convertible Preferred Stock Into Common Stock [Member]                                  
Conversion of Stock, Shares Converted (in shares)     669,022 1,183,151 3,021,237 600,000                      
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        
Series B Preferred Stock [Member]                                  
Conversion of Stock, Conversion Rate (in dollars per share) | $ / shares   $ 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       $ 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)   6,393,113       7,419,353       6,393,113     7,419,353        
Stock Issued During Period, Shares, Warrant Exercises (in shares)     1,026,240                            
Proceeds from Warrant Exercises | $     $ 1,591,000                            
Warrants and Rights Outstanding | $           $ 1,210,000             $ 1,210,000        
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 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       $ 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)   7,373,880       7,419,353       7,373,880     7,419,353        
Stock Issued During Period, Shares, Warrant Exercises (in shares)     45,473                            
Proceeds from Warrant Exercises | $     $ 70,000                            
Warrants and Rights Outstanding | $           $ 2,871,000             $ 2,871,000        
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           68.8             68.8        
Series B Warrants [Member] | Measurement Input, Risk Free Interest Rate [Member]                                  
Warrants and Rights Outstanding, Measurement Input           1.58             1.58        
Series A and Series B Warrants [Member]                                  
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares           $ 1.55             $ 1.55        
Warrants and Rights Outstanding | $           $ 4,081,000             $ 4,081,000        
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   $ 1.84               $ 1.84              
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         9,893,776 9,893,776  
Warrants and Rights Outstanding | $                             $ 3,502,000 $ 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                               68.8  
Warrants Issued Upon Conversion of Term Loan with CRG [Member] | Measurement Input, Risk Free Interest Rate [Member]                                  
Warrants and Rights Outstanding, Measurement Input                               1.58  
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               $ 950             $ 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               2,220             2,220
Warrants and Rights Outstanding | $                                 $ 940,000
Share-based Payment Arrangement, Expense | $                   $ 0   $ 0          
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                                 0.551
May 2017 Issuance Related to 2017 Loan Agreement [Member] | Measurement Input, Risk Free Interest Rate [Member]                                  
Warrants and Rights Outstanding, Measurement Input                                 0.0225
May 2017 Issuance Related to 2017 Loan Agreement [Member] | Measurement Input, Expected Term [Member]                                  
Warrants and Rights Outstanding, Measurement Input | yr                                 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           $ 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, Value, Restricted Stock Award, Gross | $                                
Common Stock [Member] | Series A Warrants [Member]                                  
Stock Issued During Period, Shares, Warrant Exercises (in shares)                   1,026,240              
Common Stock [Member] | Series B Warrants [Member]                                  
Stock Issued During Period, Shares, Warrant Exercises (in shares)                   45,473              
November 2019 Offering [Member]                                  
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] | 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)           1,945,943             1,945,943        
August 2019 ATM Facility [Member]                                  
Proceeds From Issuance of Common Stock, Net | $                     $ 6,322,000     $ 6,322,000      
Stock Issued During Period, Shares, New Issues (in shares)                     1,004,171     1,004,171      
Aggregate Offering Price | $ $ 6,760,000             $ 6,760,000