<TABLE> <S> <C>

<PAGE>

<ARTICLE> 5
<RESTATED>

<S>                             <C>                     <C>                     <C>
<PERIOD-TYPE>                   3-MOS                   6-MOS                   9-MOS
<FISCAL-YEAR-END>                          DEC-31-1996             DEC-31-1996             DEC-31-1996
<PERIOD-START>                             JAN-01-1996             JAN-01-1996             JAN-01-1996
<PERIOD-END>                               MAR-31-1996             JUN-30-1996             SEP-30-1996
<CASH>                                          22,355                  17,457                  13,930
<SECURITIES>                                    75,401                  88,590                  99,905
<RECEIVABLES>                                   43,898                  40,977                  45,013
<ALLOWANCES>                                     (638)                   (645)                   (751)
<INVENTORY>                                          0                       0                       0
<CURRENT-ASSETS>                               149,016                 153,648                 166,320
<PP&E>                                          39,615                  42,177                  39,339
<DEPRECIATION>                                  19,439                  20,189                  18,249
<TOTAL-ASSETS>                                 175,994                 182,938                 195,742
<CURRENT-LIABILITIES>                           34,747                  30,483                 383,323
<BONDS>                                          2,907                   2,700                   2,700
<PREFERRED-MANDATORY>                                0                       0                       0
<PREFERRED>                                          0                       0                       0
<COMMON>                                           216                     220                     224
<OTHER-SE>                                     135,385                 146,408                 151,019
<TOTAL-LIABILITY-AND-EQUITY>                   175,994                 182,938                 195,742
<SALES>                                         20,252                  39,950                  36,158
<TOTAL-REVENUES>                                49,460                 100,702                 152,104
<CGS>                                           13,612                  26,622                  27,426
<TOTAL-COSTS>                                   39,668                  80,132                 135,542
<OTHER-EXPENSES>                                     0                   9,417                       0
<LOSS-PROVISION>                                    25                      51                      95
<INTEREST-EXPENSE>                                  46                      88                     122
<INCOME-PRETAX>                                  6,248                  13,342                  20,039
<INCOME-TAX>                                     2,540                   5,311                   7,908
<INCOME-CONTINUING>                              3,708                   8,031                  12,131
<DISCONTINUED>                                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0
<CHANGES>                                            0                       0                       0
<NET-INCOME>                                     3,708                   8,031                  12,131
<EPS-PRIMARY>                                     0.15                    0.17                    0.16
<EPS-DILUTED>                                     0.14                    0.17                    0.16


</TABLE>