v3.19.2
Note 10 - Stock-based Compensation (Tables)
6 Months Ended
Jun. 30, 2019
Notes Tables  
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]
   
Three Months Ended
June 30,
   
Six Months Ended
June 30,
 
   
201
9
   
201
8
   
201
9
   
201
8
 
Cost of goods sold
  $
68
    $
74
    $
129
    $
161
 
Research and development
   
233
     
377
     
457
     
809
 
Selling, general and administrative
   
1,045
     
597
     
1,867
     
1,158
 
Total
  $
1,346
    $
1,048
    $
2,453
    $
2,128