<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE
COMPANY'S THIRD QUARTER 10-Q FOR THE PERIOD ENDING SEPTEMBER 30, 1997.
</LEGEND>
<MULTIPLIER> 1,000
<CURRENCY> US DOLLARS
       
                             
<PERIOD-TYPE>                   9-MOS
<FISCAL-YEAR-END>                          DEC-31-1997
<PERIOD-START>                             JAN-01-1997
<PERIOD-END>                               SEP-30-1997
<EXCHANGE-RATE>                                    1.0
<CASH>                                         177,191
<SECURITIES>                                   106,092
<RECEIVABLES>                                        0
<ALLOWANCES>                                         0
<INVENTORY>                                          0
<CURRENT-ASSETS>                               285,466
<PP&E>                                          32,784
<DEPRECIATION>                                  22,602
<TOTAL-ASSETS>                                 298,727
<CURRENT-LIABILITIES>                           11,758
<BONDS>                                              0
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                           251
<OTHER-SE>                                     281,230
<TOTAL-LIABILITY-AND-EQUITY>                   298,727
<SALES>                                              0
<TOTAL-REVENUES>                                32,620
<CGS>                                                0
<TOTAL-COSTS>                                   45,215
<OTHER-EXPENSES>                                     0
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                                 438
<INCOME-PRETAX>                               (13,033)
<INCOME-TAX>                                         0
<INCOME-CONTINUING>                                  0
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                  (13,033)
<EPS-PRIMARY>                                   (0.54)
<EPS-DILUTED>                                   (0.54)