<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE
FINANCIAL STATEMENTS REFERENCED BELOW AND IS QUALIFIED IN ITS ENTIRETY BY
REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<RESTATED> 
<MULTIPLIER> 1,000
       
<S>                             <C>                     <C>                     <C>
<PERIOD-TYPE>                   3-MOS                   6-MOS                   9-MOS
<FISCAL-YEAR-END>                          DEC-31-1997             DEC-31-1997             DEC-31-1997
<PERIOD-START>                             JAN-01-1997             JAN-01-1997             JAN-01-1997
<PERIOD-END>                               MAR-31-1997             JUN-30-1997             SEP-30-1997
<CASH>                                            2184                    2539                    2423
<SECURITIES>                                     15272                   18722                   21026
<RECEIVABLES>                                    21274                   21137                   21825
<ALLOWANCES>                                      5171                    5268                    5028
<INVENTORY>                                       7852                    8068                    8407
<CURRENT-ASSETS>                                 47475                   51198                   54628
<PP&E>                                           16546                   17031                   17365
<DEPRECIATION>                                    9428                   10053                   10688
<TOTAL-ASSETS>                                   59418                   60639                   63512
<CURRENT-LIABILITIES>                             5486                    5022                    5061
<BONDS>                                            333                     333                     333
<PREFERRED-MANDATORY>                                0                       0                       0
<PREFERRED>                                          0                       0                       0
<COMMON>                                         12866                   12038                   12188
<OTHER-SE>                                       40733                   43246                   45930
<TOTAL-LIABILITY-AND-EQUITY>                     59418                   60639                   63512
<SALES>                                          18025                   36469                   54878
<TOTAL-REVENUES>                                 18025                   36469                   54878
<CGS>                                             4723                    9430                   14269
<TOTAL-COSTS>                                     4723                    9430                   14269
<OTHER-EXPENSES>                                  9617                   19514                   28925
<LOSS-PROVISION>                                   511                    1120                    1723
<INTEREST-EXPENSE>                                   0                       0                       2
<INCOME-PRETAX>                                   3914                    8000                   12365
<INCOME-TAX>                                      1507                    3080                    4761
<INCOME-CONTINUING>                               2407                    4920                    7604
<DISCONTINUED>                                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0
<CHANGES>                                            0                       0                       0
<NET-INCOME>                                      2407                    4920                    7604
<EPS-PRIMARY>                                      .30                     .60                     .94
<EPS-DILUTED>                                      .29                     .59                     .92
        

</TABLE>