Note 7 - Provision for Income Taxes (Tables)
 9 Months Ended
Sep. 30, 2016
Notes Tables  
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]
   
Three months ended September 30:
    
Nine months ended September 30:
  
   
2016
    
2015
    
2016
    
2015
  
(Benefit)/provision for income taxes
   $ (3,868 )   $ 2,060     $ (12,657 )   $ 8,062  
Effective tax rate
     (43.0% )     29.8 %     (50.6% )     32.5 %