<ARTICLE> 5
<LEGEND>
This schedule contains summary financial information extracted from the
Company's second quarter 10-Q for the period ending June 30, 1997 and is
qualified in its entirety by reference to such financial statements.
</LEGEND>
<MULTIPLIER> 1,000
<CURRENCY> U.S. DOLLARS
       
                             
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          DEC-31-1997
<PERIOD-START>                             JAN-01-1997
<PERIOD-END>                               JUN-30-1997
<EXCHANGE-RATE>                                    1.0
<CASH>                                         188,584
<SECURITIES>                                    97,582
<RECEIVABLES>                                        0
<ALLOWANCES>                                         0
<INVENTORY>                                          0
<CURRENT-ASSETS>                               287,808
<PP&E>                                          31,688
<DEPRECIATION>                                  21,681
<TOTAL-ASSETS>                                 300,666
<CURRENT-LIABILITIES>                            9,268
<BONDS>                                              0
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                           251
<OTHER-SE>                                     285,701
<TOTAL-LIABILITY-AND-EQUITY>                   300,666
<SALES>                                              0
<TOTAL-REVENUES>                                19,073
<CGS>                                                0
<TOTAL-COSTS>                                   25,953
<OTHER-EXPENSES>                                     0
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                                 298
<INCOME-PRETAX>                                (7,178)
<INCOME-TAX>                                         0
<INCOME-CONTINUING>                                  0
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                   (7,178)
<EPS-PRIMARY>                                   (0.31)
<EPS-DILUTED>                                   (0.31)