<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM QUARTERLY
REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
FOR THE QUARTERLY PERIOD ENDED SEPTEMBER 30, 1998
</LEGEND>
<MULTIPLIER> 1,000
       
<S>                             <C>                     <C>                     <C>                     <C>
<PERIOD-TYPE>                   3-MOS                   9-MOS                   3-MOS                   9-MOS
<FISCAL-YEAR-END>                          DEC-31-1998             DEC-31-1998             DEC-31-1997             DEC-31-1997
<PERIOD-START>                             JUL-01-1998             JAN-01-1998             JUL-01-1997             JAN-01-1997
<PERIOD-END>                               SEP-30-1998             SEP-30-1998             SEP-30-1997             SEP-30-1997
<CASH>                                         134,397                       0                       0                       0
<SECURITIES>                                         0                       0                       0                       0
<RECEIVABLES>                                    4,983                       0                       0                       0
<ALLOWANCES>                                       387                       0                       0                       0
<INVENTORY>                                        289                       0                       0                       0
<CURRENT-ASSETS>                               144,642                       0                       0                       0
<PP&E>                                          52,076                       0                       0                       0
<DEPRECIATION>                                  21,671                       0                       0                       0
<TOTAL-ASSETS>                                 273,342                       0                       0                       0
<CURRENT-LIABILITIES>                           47,199                       0                       0                       0
<BONDS>                                              0                       0                       0                       0
<PREFERRED-MANDATORY>                                0                       0                       0                       0
<PREFERRED>                                         41                       0                       0                       0
<COMMON>                                           285                       0                       0                       0
<OTHER-SE>                                     218,529                       0                       0                       0
<TOTAL-LIABILITY-AND-EQUITY>                   273,342                       0                       0                       0
<SALES>                                              0                       0                       0                       0
<TOTAL-REVENUES>                                49,824                 117,640                  21,009                  56,427
<CGS>                                                0                       0                       0                       0
<TOTAL-COSTS>                                   21,568                  53,893                   9,656                  27,154
<OTHER-EXPENSES>                                48,650                 101,902                  18,151                  51,549
<LOSS-PROVISION>                                   991                   2,678                     840                   2,814
<INTEREST-EXPENSE>                                 353                   1,661                     516                   1,467
<INCOME-PRETAX>                               (20,394)                (38,155)                 (6,798)                (22,276)
<INCOME-TAX>                                         0                       0                       0                       0
<INCOME-CONTINUING>                           (20,394)                (38,155)                 (6,798)                (22,276)
<DISCONTINUED>                                       0                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0                       0
<CHANGES>                                            0                       0                       0                       0
<NET-INCOME>                                  (22,104)                (41,578)                 (7,198)                (23,327)
<EPS-PRIMARY>                                   (0.78)                  (1.64)                  (0.36)                  (1.22)
<EPS-DILUTED>                                   (0.78)                  (1.64)                  (0.36)                  (1.22)
        

</TABLE>