<ARTICLE>                     5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE
CONSOLIDATED BALANCE SHEET AND THE CONSOLIDATED STATEMENT OF OPERATIONS AND IS
QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<MULTIPLIER>                    1,000
       
                             
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                        DEC-31-1998
<PERIOD-END>                             JUN-30-1998
<CASH>                                        13,817
<SECURITIES>                                  34,565
<RECEIVABLES>                                 32,437
<ALLOWANCES>                                       0
<INVENTORY>                                    5,901
<CURRENT-ASSETS>                              91,833
<PP&E>                                        25,590
<DEPRECIATION>                                17,726
<TOTAL-ASSETS>                               110,086
<CURRENT-LIABILITIES>                         10,346
<BONDS>                                            0
<PREFERRED-MANDATORY>                              0
<PREFERRED>                                        0
<COMMON>                                         485
<OTHER-SE>                                    95,422
<TOTAL-LIABILITY-AND-EQUITY>                 110,086
<SALES>                                       32,659
<TOTAL-REVENUES>                              36,086
<CGS>                                          5,006
<TOTAL-COSTS>                                 24,653
<OTHER-EXPENSES>                                   0
<LOSS-PROVISION>                                   0
<INTEREST-EXPENSE>                                40
<INCOME-PRETAX>                               11,393
<INCOME-TAX>                                   3,485
<INCOME-CONTINUING>                            7,908
<DISCONTINUED>                                     0
<EXTRAORDINARY>                                    0
<CHANGES>                                          0
<NET-INCOME>                                   7,908
<EPS-PRIMARY>                                   0.17
<EPS-DILUTED>                                   0.16