Quarterly report pursuant to Section 13 or 15(d)

Note 1 - The Company and Basis of Presentation (Details Textual)

v3.20.1
Note 1 - The Company and Basis of Presentation (Details Textual) - USD ($)
1 Months Ended 3 Months Ended 11 Months Ended 12 Months Ended
Nov. 26, 2019
Nov. 12, 2019
Aug. 16, 2019
Feb. 29, 2020
Jan. 31, 2020
Dec. 31, 2019
Nov. 30, 2019
Aug. 31, 2019
Mar. 31, 2020
Sep. 30, 2019
Mar. 31, 2019
Nov. 30, 2019
Dec. 31, 2019
Dec. 31, 2018
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)                 23,665,905          
Proceeds from Warrant Exercises                 $ 1,661,000        
Retained Earnings (Accumulated Deficit), Ending Balance           $ (197,911,000) [1]     (204,221,000)       $ (197,911,000) [1]  
Cash and Cash Equivalents, at Carrying Value, Ending Balance           $ 13,308,000 [1]     9,042,000   17,821,000   $ 13,308,000 [1] $ 29,523,000
Working Capital                 12,399,000          
Net Cash Provided by (Used in) Operating Activities, Total                 $ (5,736,000)   $ (11,558,000)      
Conversion of Term Loan with CRG Into Stock and Warrants [Member]                            
Debt Conversion, Original Debt, Amount   $ 28,981,000                        
Debt Conversion, Converted Instrument, Amount   $ 31,300,000                        
Conversion of Term Loan with CRG Into Series B Convertible Preferred Stock [Member]                            
Debt Conversion, Converted Instrument, Shares Issued (in shares) 31,300 31,300                        
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)   $ 1.53                        
Series B Convertible Preferred Stock Into Common Stock [Member] | Maximum [Member]                            
Conversion of Stock, Conversion Rate (in dollars per share)   $ 1.836                        
Series A Preferred Stock [Member]                            
Convertible Preferred Stock, Shares Issued upon Conversion (in shares)             1   1     1    
Preferred Stock, Shares Outstanding, Ending Balance (in shares)           1,852,173 [2]     0       1,852,173 [2]  
Series A Convertible Preferred Stock [Member]                            
Preferred Stock, Shares Outstanding, Ending Balance (in shares)                 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)             $ 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)             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                    
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)             $ 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)             7,419,353   7,373,880     7,419,353    
Stock Issued During Period, Shares, Warrant Exercises (in shares)       45,473                    
Proceeds from Warrant Exercises       $ 70,000                    
Warrants Issued Upon Conversion of Term Loan with CRG [Member]                            
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)                 $ 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          
Class of Warrants and Rights Outstanding, Exercise Price Percentage of Conversion Rate   120.00%                        
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)             $ 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)             $ 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)             $ 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)             $ 1.55         $ 1.55    
Warrants and Rights Outstanding, Term (Year)             5 years         5 years    
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] | Class A Units [Member]                            
Shares Issued, Price Per Share (in dollars per share)             $ 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)             $ 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            
Stock Issued During Period, Shares, New Issues (in shares)                 0          
November 2017 ATM Facility [Member]                            
Stock Issued During Period, Shares, New Issues (in shares)                 0   0      
[1] The condensed consolidated balance sheet as of December 31, 2019 has been derived from the audited consolidated financial statements as of that date.
[2] The condensed consolidated balance sheet as of December 31, 2019 has been derived from the audited consolidated financial statements as of that date.