<ARTICLE>                     5
<MULTIPLIER>               1000
       
                                                        
<PERIOD-TYPE>               6-MOS                             6-MOS
<FISCAL-YEAR-END>           Dec-31-1997                       Dec-31-1998
<PERIOD-END>                Jun-30-1997                       Jun-30-1998
<CASH>                      7582                              13205
<SECURITIES>                16851                             73901
<RECEIVABLES>               17825<F1>                         16775<F1>
<ALLOWANCES>                0                                 0
<INVENTORY>                 8672                              9815
<CURRENT-ASSETS>            58547                             119577
<PP&E>                      35491<F2>                         38465<F2>
<DEPRECIATION>              0                                 0
<TOTAL-ASSETS>              101041                            164465
<CURRENT-LIABILITIES>       22190                             14277
<BONDS>                     0                                 0
<PREFERRED-MANDATORY>       0                                 0
<PREFERRED>                 0                                 0
<COMMON>                    179                               205
<OTHER-SE>                  60606                             130514
<TOTAL-LIABILITY-AND-EQUITY>101041                            164465
<SALES>                     46034                             49006
<TOTAL-REVENUES>            46034                             49006
<CGS>                       22901                             23484
<TOTAL-COSTS>               22901                             23484
<OTHER-EXPENSES>            5108<F3>                          6053<F3>
<LOSS-PROVISION>            0                                 0
<INTEREST-EXPENSE>          825                               797
<INCOME-PRETAX>             7067                              9121
<INCOME-TAX>                1910                              3054
<INCOME-CONTINUING>         0                                 0
<DISCONTINUED>              0                                 0
<EXTRAORDINARY>             0                                 0
<CHANGES>                   0                                 0
<NET-INCOME>                5132                              5999
<EPS-PRIMARY>                 .30                               .32
<EPS-DILUTED>     .27                               .30


<FN>
<F1>Net of  allowance  for doubtful  accounts,  consistent  with  balance  sheet
presentation.
<F2>Net of accumulated depreciation, consistent with balance sheet
presentation.
<F3>Research and development expenses
</FN>