<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE
CONSOLIDATED FINANCIAL STATEMENTS FOR THE PERIOD ENDED AS SPECIFIED 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-31-1997
<PERIOD-END>                               MAR-31-1997             JUN-30-1997             SEP-30-1997
<CASH>                                          12,077                  18,487                  20,126
<SECURITIES>                                     8,577                   3,995                   5,658
<RECEIVABLES>                                    3,648                   3,237                   4,261
<ALLOWANCES>                                       802                     790                     969
<INVENTORY>                                        134                     104                     107
<CURRENT-ASSETS>                                24,757                  26,478                  30,470
<PP&E>                                           8,111                   8,622                   9,101
<DEPRECIATION>                                   4,399                   4,866                   5,173
<TOTAL-ASSETS>                                  37,357                  38,900                  41,244
<CURRENT-LIABILITIES>                            3,487                   3,728                   4,548
<BONDS>                                            125                     106                      87
<PREFERRED-MANDATORY>                                0                       0                       0
<PREFERRED>                                          0                       0                       0
<COMMON>                                            98                      98                      98
<OTHER-SE>                                      33,648                  34,968                  36,511
<TOTAL-LIABILITY-AND-EQUITY>                    37,357                  38,900                  41,244
<SALES>                                          1,958                   4,024                   5,819
<TOTAL-REVENUES>                                 8,070                  16,215                  25,207
<CGS>                                              315                     706                   1,058
<TOTAL-COSTS>                                    1,261                   2,633                   4,125
<OTHER-EXPENSES>                                 5,096                  10,292                  15,902
<LOSS-PROVISION>                                     1                      35                      55
<INTEREST-EXPENSE>                                   4                       8                      12
<INCOME-PRETAX>                                  1,931                   3,792                   5,964
<INCOME-TAX>                                       686                   1,300                   2,017
<INCOME-CONTINUING>                                  0                       0                       0
<DISCONTINUED>                                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0
<CHANGES>                                            0                       0                       0
<NET-INCOME>                                     1,245                   2,492                   3,947
<EPS-PRIMARY>                                     0.13                    0.25                    0.40
<EPS-DILUTED>                                     0.12                    0.25                    0.39


</TABLE>