<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE
COMPANY'S QUARTERLY REPORT ON FORM 10-Q FOR THE SIX MONTHS ENDED JUNE 30, 1998 
AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<MULTIPLIER> 1,000
<CURRENCY> U.S. DOLLAR
       
                             
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          DEC-31-1998
<PERIOD-START>                             JAN-01-1998
<PERIOD-END>                               JUN-30-1998
<EXCHANGE-RATE>                                    1.0
<CASH>                                          36,274
<SECURITIES>                                   219,864
<RECEIVABLES>                                        0
<ALLOWANCES>                                         0
<INVENTORY>                                          0
<CURRENT-ASSETS>                               257,926
<PP&E>                                          39,217
<DEPRECIATION>                                  25,600
<TOTAL-ASSETS>                                 274,900
<CURRENT-LIABILITIES>                                0
<BONDS>                                              0
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                           253
<OTHER-SE>                                     259,086
<TOTAL-LIABILITY-AND-EQUITY>                   274,900
<SALES>                                              0
<TOTAL-REVENUES>                                14,321
<CGS>                                                0
<TOTAL-COSTS>                                   32,230
<OTHER-EXPENSES>                                     0
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                                 307
<INCOME-PRETAX>                               (18,216)
<INCOME-TAX>                                         0
<INCOME-CONTINUING>                           (18,216)
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                  (18,216)
<EPS-PRIMARY>                                   (0.72)
<EPS-DILUTED>                                   (0.72)