<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<RESTATED>

<S>                             <C>                     <C>                     <C>
<PERIOD-TYPE>                   3-MOS                   3-MOS                   3-MOS
<FISCAL-YEAR-END>                          DEC-31-1997             DEC-31-1997             DEC-31-1997
<PERIOD-START>                             JAN-01-1997             APR-01-1997             JUL-01-1997
<PERIOD-END>                               MAR-31-1997             JUN-30-1997             SEP-30-1997
<CASH>                                          13,654                  15,014                   7,150
<SECURITIES>                                    51,500                  49,222                  57,766
<RECEIVABLES>                                   21,562                  26,362                  31,544
<ALLOWANCES>                                       160                     260                     361
<INVENTORY>                                          0                       0                       0
<CURRENT-ASSETS>                                88,734                  92,980                  99,742
<PP&E>                                           9,835                  13,413                  17,536
<DEPRECIATION>                                   3,244                   3,708                   4,329
<TOTAL-ASSETS>                                  97,468                 104,839                 113,795
<CURRENT-LIABILITIES>                           12,635                  16,450                  19,537
<BONDS>                                              0                       0                       0
<PREFERRED-MANDATORY>                                0                       0                       0
<PREFERRED>                                          0                       0                       0
<COMMON>                                            21                      22                      22
<OTHER-SE>                                      83,638                  88,366                  93,060
<TOTAL-LIABILITY-AND-EQUITY>                    97,468                 104,839                 113,795
<SALES>                                              0                       0                       0
<TOTAL-REVENUES>                                34,945                  41,132                  45,515
<CGS>                                                0                       0                       0
<TOTAL-COSTS>                                   20,867                  24,494                  26,519
<OTHER-EXPENSES>                                10,555                  12,493                  14,602
<LOSS-PROVISION>                                     0                     100                     201
<INTEREST-EXPENSE>                                   1                      32                       0
<INCOME-PRETAX>                                  4,263                   4,940                   5,302
<INCOME-TAX>                                     1,714                   2,003                   2,093
<INCOME-CONTINUING>                              2,549                   2,937                   3,209
<DISCONTINUED>                                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0
<CHANGES>                                            0                       0                       0
<NET-INCOME>                                     2,549                   2,937                   3,209
<EPS-PRIMARY>                                      .12                     .13                     .14
<EPS-DILUTED>                                      .11                     .13                     .13


</TABLE>