v3.19.3
Note 2 - Summary of Significant Accounting Policies (Details Textual) - USD ($)
1 Months Ended 3 Months Ended 6 Months Ended 12 Months Ended
Oct. 31, 2018
Jun. 30, 2019
Jun. 30, 2019
Dec. 31, 2018
Jan. 01, 2019
Impairment of Long-Lived Assets Held-for-use     $ 0 $ 0  
Payments of Dividends, Total     0    
Grant Reimbursements   $ 1,104,000 1,198,000    
Reclassification of Warrant into Equity   234,000 234,000    
Gain (Loss) on Extinguishment of Debt, Total $ 11,000        
Operating Lease, Liability, Total   840,000 840,000    
Lessee, Operating Lease, Liability, Payments, Due, Total   1,007,000 1,007,000    
Operating Lease, Right-of-Use Asset   779,000 779,000  
Accounting Standards Update 2016-02 [Member]          
Operating Lease, Liability, Total         $ 227,000
Lessee, Operating Lease, Liability, Payments, Due, Total         $ 239,000
Lessee, Operating Lease, Discount Rate         9.41%
Operating Lease, Right-of-Use Asset         $ 227,000
Modified March 2018 and Modified September 2018 Notes [Member]          
Embedded Derivative, Fair Value of Embedded Derivative Asset   0 0 0  
Embedded Derivative, Fair Value of Embedded Derivative Liability   0 0 0  
Research and Development Expense [Member]          
Collaboration Initiation Payment   75,000 75,000    
Money Market Funds [Member]          
Restricted Cash, Total   200,000 200,000    
Letter of Credit 1 [Member]          
Restricted Cash, Total   $ 55,000 $ 55,000 55,000  
Minimum [Member]          
Property, Plant and Equipment, Useful Life     3 years    
Maximum [Member]          
Property, Plant and Equipment, Useful Life     5 years    
Grants Receivable       $ 5,700,000  
Accounts Payable 1 [Member] | Supplier Concentration Risk [Member] | Vendor 1 [Member]          
Concentration Risk, Percentage     26.00% 52.00%  
Accounts Payable 1 [Member] | Supplier Concentration Risk [Member] | Vendor 2 [Member]          
Concentration Risk, Percentage     22.00% 26.00%  
Accounts Payable 1 [Member] | Supplier Concentration Risk [Member] | Vendor 3 [Member]          
Concentration Risk, Percentage     17.00% 15.00%  
Accounts Payable 1 [Member] | Supplier Concentration Risk [Member] | Two of the Three Vendors Supporting Clinical Study Activities [Member]          
Concentration Risk, Percentage     44.00% 67.00%