Note 5 - Amounts Receivable (Tables)
 3 Months Ended
Mar. 31, 2020
Notes Tables  
Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]
   
March 31, 2020
    
December 31, 2019
  
Research and development incentives
   $
908
     $
793
  
Sales-based taxes receivable
    
38
      
13
  
Other
    
39
      
17
  
Total amounts receivable
   $
985
     $
823