v3.19.3
Note 2 - Summary of Significant Accounting Policies (Details Textual) - USD ($)
1 Months Ended 3 Months Ended 9 Months Ended 12 Months Ended
May 31, 2019
Oct. 31, 2018
Sep. 30, 2019
Sep. 30, 2019
Dec. 31, 2018
Jan. 01, 2019
Impairment of Long-Lived Assets Held-for-use       $ 0 $ 0  
Grant Reimbursements     $ 700,000 1,900,000    
Gain (Loss) on Extinguishment of Debt, Total   $ 11,000        
Operating Lease, Liability, Total     743,000 743,000    
Lessee, Operating Lease, Liability, Payments, Due, Total     891,000 891,000    
Operating Lease, Right-of-Use Asset     687,000 687,000  
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          
Money Market Funds [Member]            
Restricted Cash, Total     198,000 198,000    
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] | Nitto-Denko Avecia, Inc. [Member]            
Concentration Risk, Percentage       26.00%    
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       26.00% 26.00%  
Accounts Payable 1 [Member] | Supplier Concentration Risk [Member] | Vendor 3 [Member]            
Concentration Risk, Percentage       23.00% 15.00%  
Accounts Payable 1 [Member] | Supplier Concentration Risk [Member] | Two of the Three Vendors Supporting Clinical Study Activities [Member]            
Concentration Risk, Percentage         67.00%