<PAGE>
 
                                                                      Exhibit 11

                       COMPUTATION OF EARNINGS PER SHARE

<TABLE>
<CAPTION>
                                                         THREE MONTHS ENDED            SIX MONTHS ENDED
                                                              JUNE 30,                     JUNE 30,
                                                   -----------------------------  --------------------------
                                                         1997          1996           1997          1996
                                                   -------------- --------------  -------------- -----------
<S>                                                <C>            <C>             <C>            <C>                      
PRIMARY:                                                                                                                  
Net income (loss)                                     $(17,183,000)  $ 2,862,000  $(23,002,000)  $ 4,906,000              
                                                   ===============  ============  ============   ===========            
Shares as adjusted:                                                                                                       
 Weighted average common shares outstanding             23,929,771    23,384,472    23,926,771    21,931,074              
 Incremental shares from outstanding stock                                                                                
   options as determined under the treasury                                                                               
   stock method                                                 --       380,762            --       366,594              
                                                   ---------------  ------------  ------------   -----------            
                                                                                                                          
Shares as adjusted                                      23,929,771    23,765,234    23,926,771    22,297,668              
                                                   ===============  ============  ============   ===========            
                                                                                                                          
Net income (loss) per share                           $       (.72)  $       .12  $       (.96)  $       .22              
                                                   ===============  ============  ============   ===========            
                                                                                                                          
                                                                                                                          
FULLY DILUTED:                                                                                                            
Net income (loss)                                     $(17,183,000)  $ 2,862,000  $(23,002,000)  $ 4,906,000              
                                                   ===============  ============  ============   ===========            
Shares as adjusted:                                                                                                       
 Weighted average common shares outstanding             23,929,771    23,384,472    23,926,771    21,931,074              
 Incremental shares from outstanding stock                                                                                
   options as determined under the treasury                                                                               
   stock method                                                 --       393,442            --       410,619              
                                                   ---------------  ------------  ------------   -----------            
                                                                                                                          
Shares as adjusted                                      23,929,771    23,777,914    23,926,771    22,341,693              
                                                   ===============  ============  ============   ===========            
                                                                                                                          
Net income (loss) per share                           $       (.72)  $       .12  $       (.96)  $       .22              
                                                   ===============  ============  ============   ===========            
</TABLE>