text: Aggregate amortization expense for patents and goodwill was $304,000, $304,000 and $907,000 for 2003, 2002 and 2001, respectively. 
  
  Estimated future amortization expense for each of the years ending December 31, is as follows (in thousands): 
  
  2004  $ 304 
  
  2005  $ 271 
  
  2006  $ 169 
  
  2007  $ 144 
  
  2008  $ 144 
  
  There was no change in the carrying amounts of goodwill for 2003. 