<TABLE> <S> <C>

<PAGE>
 
<ARTICLE> 5
<RESTATED>
       
<S>                             <C>                     <C>                     <C>
<PERIOD-TYPE>                    3-MOS                    6-MOS                   9-MOS         
<FISCAL-YEAR-END>                          MAR-31-1998             MAR-31-1998             MAR-31-1998
<PERIOD-START>                             APR-01-1997             APR-01-1997             APR-01-1997
<PERIOD-END>                               JUN-30-1997             SEP-30-1997             DEC-31-1997
<CASH>                                         175,800                 141,484                  49,589
<SECURITIES>                                   127,556                 150,094                 236,147
<RECEIVABLES>                                   50,859                  57,845                  66,047
<ALLOWANCES>                                     1,948                   3,496                   2,933
<INVENTORY>                                          0                       0                       0
<CURRENT-ASSETS>                               371,794                 362,391                 368,281
<PP&E>                                          72,470                  75,262                  75,192
<DEPRECIATION>                                  34,249                  37,544                  40,526
<TOTAL-ASSETS>                                 431,531                 419,083                 429,306
<CURRENT-LIABILITIES>                          103,707                 147,877                 148,608
<BONDS>                                          3,362                   3,466                   3,453
<PREFERRED-MANDATORY>                                0                       0                       0
<PREFERRED>                                          0                       0                       0
<COMMON>                                           892                     876                     886
<OTHER-SE>                                     323,952                 262,429                 271,904
<TOTAL-LIABILITY-AND-EQUITY>                   431,531                 419,083                 429,306
<SALES>                                         38,355                  84,610                 132,983
<TOTAL-REVENUES>                                66,148                 141,116                 223,422
<CGS>                                            3,873                   8,775                  13,961
<TOTAL-COSTS>                                   15,283                  29,199                  45,893
<OTHER-EXPENSES>                                48,946                 179,384                 235,176
<LOSS-PROVISION>                                     0                       0                       0
<INTEREST-EXPENSE>                             (4,585)                 (9,301)                (13,305)
<INCOME-PRETAX>                                  6,504                (58,166)                (44,342)
<INCOME-TAX>                                     1,376                   1,325                   4,781
<INCOME-CONTINUING>                              5,128                (59,491)                (49,123)
<DISCONTINUED>                                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0
<CHANGES>                                            0                       0                       0
<NET-INCOME>                                     5,128                (59,491)                (49,123)
<EPS-PRIMARY>                                    $0.06                 ($0.68)                 ($0.56)
<EPS-DILUTED>                                    $0.06                 ($0.68)                 ($0.56)
        

</TABLE>