<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<MULTIPLIER> 1,000
       
<S>                             <C>                     <C>                     <C>                     <C>
<PERIOD-TYPE>                   12-MOS                   9-MOS                   12-MOS                   3-MOS
<FISCAL-YEAR-END>                          SEP-30-1995             SEP-30-1996             SEP-30-1996             SEP-30-1997
<PERIOD-START>                             OCT-01-1994             OCT-01-1995             OCT-01-1995             OCT-01-1996
<PERIOD-END>                               SEP-30-1995             JUN-30-1996             SEP-30-1996             DEC-31-1996
<CASH>                                           1,022                   2,845                   2,113                  29,817
<SECURITIES>                                         0                       0                       0                       0
<RECEIVABLES>                                    2,315                   3,506                   4,719                   4,030
<ALLOWANCES>                                       151                     113                     107                     293
<INVENTORY>                                         72                      96                       0                     219
<CURRENT-ASSETS>                                 3,478                   7,018                   7,716                  34,244
<PP&E>                                           1,392                   3,329                   3,841                   4,278
<DEPRECIATION>                                     503                     855                       0                   1,376
<TOTAL-ASSETS>                                   4,770                   9,877                  10,722                  37,375
<CURRENT-LIABILITIES>                            2,769                   3,981                   4,552                   5,767
<BONDS>                                            230                     337                     322                       0
<PREFERRED-MANDATORY>                            1,140                   4,664                   4,664                       0
<PREFERRED>                                          0                       0                       0                       0
<COMMON>                                             5                       5                       4                       8
<OTHER-SE>                                         626                     850                   1,180                  31,333
<TOTAL-LIABILITY-AND-EQUITY>                     4,770                   9,877                  10,722                  37,375
<SALES>                                         11,937                  13,784                  19,884                   6,298
<TOTAL-REVENUES>                                11,937                  13,784                  19,884                   6,298
<CGS>                                            2,171                   1,957                   3,053                     957
<TOTAL-COSTS>                                    2,171                   1,957                   3,003                     957
<OTHER-EXPENSES>                                 9,574                  11,767                  16,410                   5,441
<LOSS-PROVISION>                                   148                       0                       0                      65
<INTEREST-EXPENSE>                                  53                      35                       0                      18
<INCOME-PRETAX>                                    182                     129                     515                      15
<INCOME-TAX>                                       106                     (73)                    (24)                    158
<INCOME-CONTINUING>                                 76                     202                     539                    (143)
<DISCONTINUED>                                       0                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0                       0
<CHANGES>                                            0                       0                       0                       0
<NET-INCOME>                                        76                     202                     539                    (143)
<EPS-PRIMARY>                                     0.02                    0.04                    0.11                   (0.01)
<EPS-DILUTED>                                     0.02                    0.04                    0.07                   (0.01)
        

</TABLE>