Annual report pursuant to Section 13 and 15(d)

Note 9 - Common Stock (Details Textual)

v3.19.1
Note 9 - Common Stock (Details Textual)
1 Months Ended 2 Months Ended 12 Months Ended 14 Months Ended
Jun. 08, 2018
USD ($)
$ / shares
shares
Feb. 12, 2018
USD ($)
$ / shares
shares
Nov. 08, 2017
USD ($)
Mar. 22, 2017
USD ($)
$ / shares
shares
Dec. 31, 2018
USD ($)
$ / shares
shares
May 19, 2017
USD ($)
$ / shares
shares
Dec. 31, 2017
USD ($)
shares
Dec. 31, 2018
USD ($)
$ / shares
shares
Dec. 31, 2017
USD ($)
shares
Dec. 31, 2018
USD ($)
$ / shares
shares
May 22, 2017
USD ($)
yr
$ / shares
shares
Jun. 20, 2016
USD ($)
$ / shares
shares
Shares Issued, Price Per Share | $ / shares $ 2.56                      
Proceeds from Issuance of Common Stock               $ 53,792,000 $ 31,565,000      
Stock Issued During Period, Shares, Restricted Stock Award, Gross | shares 100,000                      
Stock Issued During Period, Value, Restricted Stock Award, Gross $ 256,000             $ 336,000 $ 226,000      
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares         642,622     642,622   642,622    
Debt Instrument, Unamortized Discount, Total         $ 1,223,000     $ 1,223,000   $ 1,223,000    
Class of Warrants or Rights, Exercises in Period | shares               0 0      
Class of Warrant or Right Number of Securities Called by Warrants or Rights Cancelled In Period | shares               0 0      
Allocated Share-based Compensation Expense, Total               $ 3,035,000 $ 1,872,000      
The 2016 Loan Agreement [Member]                        
Debt Issuance Costs, Net, Total                       $ 90,000
Amortization of Debt Discount (Premium)                 371,000      
The 2017 Loan Agreement [Member]                        
Debt Issuance Costs, Net, Total             $ 790,000   790,000      
Amortization of Debt Discount (Premium)               325,000 183,000      
Debt Instrument, Unamortized Discount, Total         $ 1,223,000     $ 1,223,000   $ 1,223,000    
June 2016 Issuance Related to 2016 Loan Agreement [Member]                        
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares         100,402     100,402   100,402   100,402
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares         $ 4.98     $ 4.98   $ 4.98   $ 4.98
Warrants and Rights Outstanding                       $ 350,000
May 2017 Issuance Related to 2017 Loan Agreement [Member]                        
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares         222,049     222,049   222,049 222,049  
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares         $ 9.50     $ 9.50   $ 9.50 $ 9.50  
Warrants and Rights Outstanding                     $ 940,000  
Warrants and Rights Outstanding, Term                     10 years  
Allocated Share-based Compensation Expense, Total               $ 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  
Restricted Stock [Member]                        
Stock Issued During Period, Shares, New Issues | shares           35,000            
Shares Issued, Price Per Share | $ / shares           $ 7.42            
Stock Issued During Period, Value, New Issues           $ 260,000            
December 2018 Offering [Member]                        
Stock Issued During Period, Shares, New Issues | shares         14,728,504              
Shares Issued, Price Per Share | $ / shares         $ 1.50     $ 1.50   $ 1.50    
Proceeds from Issuance of Common Stock         $ 22,093,000              
Proceeds From Issuance of Common Stock, Net         $ 20,385,000              
Stock Issued During Period, Value, New Issues               $ 20,385,000        
February 2018 Offering [Member]                        
Stock Issued During Period, Shares, New Issues | shares   11,500,000                    
Shares Issued, Price Per Share | $ / shares   $ 3                    
Proceeds from Issuance of Common Stock   $ 34,500,000                    
Proceeds From Issuance of Common Stock, Net   $ 32,214,000                    
Stock Issued During Period, Value, New Issues               $ 32,214,000        
November 2017 ATM Facility [Member]                        
Stock Issued During Period, Shares, New Issues | shares             59,249 277,249 59,249 336,498    
Proceeds From Issuance of Common Stock, Net               $ 1,193,000 $ 125,000 $ 1,318,000    
Aggregate Offering Price     $ 25,000,000                  
Stock Issued During Period, Value, New Issues               $ 1,193,000 125,000      
March 2017 Offering [Member]                        
Stock Issued During Period, Shares, New Issues | shares       8,625,000                
Shares Issued, Price Per Share | $ / shares       $ 4                
Proceeds from Issuance of Common Stock       $ 34,500,000                
Proceeds From Issuance of Common Stock, Net       $ 31,440,000                
Stock Issued During Period, Value, New Issues                 $ 31,440,000