v3.19.3
Note 2 - Summary of Significant Accounting Policies - Change in Fair Value of Preferred Stock Warrant Liability (Details) - USD ($)
$ in Thousands
9 Months Ended 12 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Dec. 31, 2018
Dec. 31, 2017
Derivative [Member]        
Change in value     $ (211)  
Embedded derivative liability from the issuance of Notes   $ 864 864  
Termination of the embedded derivative liability due to the extinguishment of the related Notes   (211) (653)  
Fair value at end of period   653    
Warrant [Member]        
Fair value, beginning of period $ 140 42 42 $ 54
Preferred stock warrants - exercised 94   1 (8)
Change in value     98 (4)
Exchange of warrants upon Merger $ (234)      
Fair value at end of period   $ 43 $ 140 $ 42