Quarterly report pursuant to Section 13 or 15(d)

Note 8 - Common Stock (Details Textual)

v3.10.0.1
Note 8 - Common Stock (Details Textual)
3 Months Ended 6 Months Ended
Jun. 08, 2018
USD ($)
$ / shares
shares
Feb. 12, 2018
USD ($)
$ / shares
shares
Nov. 08, 2017
USD ($)
Jun. 30, 2018
USD ($)
$ / shares
shares
Jun. 30, 2017
USD ($)
shares
Jun. 30, 2018
USD ($)
$ / shares
shares
Jun. 30, 2017
USD ($)
shares
May 22, 2017
USD ($)
yr
$ / shares
shares
Jun. 20, 2016
USD ($)
$ / shares
shares
Stock Issued During Period, Shares, Restricted Stock Award, Gross | shares 100,000                
Shares Issued, Price Per Share | $ / shares $ 2.56                
Stock Issued During Period, Value, Restricted Stock Award, Gross $ 256,000                
Proceeds from Issuance of Common Stock           $ 33,396,000 $ 31,440,000    
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares       642,622   642,622      
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares              
Debt Instrument, Unamortized Discount, Total       $ 1,388,000   $ 1,388,000      
Class of Warrants or Rights, Exercises in Period | shares       0 0 0 0    
Class of Warrant or Right Number of Securities Called by Warrants or Rights Cancelled In Period | shares       0 0 0 0    
Allocated Share-based Compensation Expense, Total       $ 776,000 $ 455,000 $ 1,529,000 $ 827,000    
The 2016 Loan Agreement [Member]                  
Debt Issuance Costs, Net, Total                 $ 90,000
Amortization of Debt Discount (Premium)         336,000   371,000    
The 2017 Loan Agreement [Member]                  
Debt Issuance Costs, Net, Total       786,000   786,000      
Amortization of Debt Discount (Premium)       160,000          
Debt Instrument, Unamortized Discount, Total       $ 1,388,000   $ 1,388,000      
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
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares       $ 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  
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares       $ 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 $ 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  
February 2018 Offering [Member]                  
Stock Issued During Period, Shares, New Issues | shares   11,500,000              
Share Price | $ / shares   $ 3              
Proceeds from Issuance of Common Stock   $ 34,500,000              
Proceeds From Issuance of Common Stock, Net   $ 32,213,000              
November 2017 ATM Facility [Member]                  
Stock Issued During Period, Shares, New Issues | shares           332,778      
Proceeds From Issuance of Common Stock, Net           $ 1,308,000      
Aggregate Offering Price     $ 25,000,000            
ATM Facility [Member]                  
Stock Issued During Period, Shares, New Issues | shares       65,252   273,529      
Proceeds From Issuance of Common Stock, Net       $ 172,000   $ 1,183,000