<ARTICLE> 5
<RESTATED> 
<MULTIPLIER> 1,000
       
                                                                       
<PERIOD-TYPE>                   3-MOS                   6-MOS                   9-MOS
<FISCAL-YEAR-END>                          DEC-31-1997             DEC-31-1997             DEC-31-1997
<PERIOD-START>                             JAN-01-1997             JAN-01-1997             JAN-01-1997
<PERIOD-END>                               MAR-31-1997             JUN-30-1997             SEP-30-1997
<CASH>                                           9,376                   7,152                  12,310
<SECURITIES>                                    26,829                  30,370                  22,258
<RECEIVABLES>                                        0                       0                       0
<ALLOWANCES>                                         0                       0                       0
<INVENTORY>                                          0                       0                       0
<CURRENT-ASSETS>                                36,997                  38,140                  35,194
<PP&E>                                           8,841                   9,285                  10,104
<DEPRECIATION>                                 (4,775)                 (5,224)                 (5,711)
<TOTAL-ASSETS>                                  41,806                  43,210                  40,721
<CURRENT-LIABILITIES>                            3,124                   4,724                   6,578
<BONDS>                                            444                     270                     208
<PREFERRED-MANDATORY>                                0                       0                       0
<PREFERRED>                                          0                       0                       0
<COMMON>                                            10                      10                      10
<OTHER-SE>                                      38,498                  38,322                  34,000
<TOTAL-LIABILITY-AND-EQUITY>                    41,806                  43,210                  40,721
<SALES>                                              0                       0                       0
<TOTAL-REVENUES>                                 2,152                   4,300                   6,190
<CGS>                                                0                       0                       0
<TOTAL-COSTS>                                    5,143                  11,573                  18,381
<OTHER-EXPENSES>                                     0                       0                       0
<LOSS-PROVISION>                                     0                       0                       0
<INTEREST-EXPENSE>                                  19                      34                      41
<INCOME-PRETAX>                                (2,493)                 (6,251)                (10,658)
<INCOME-TAX>                                         0                       0                       0
<INCOME-CONTINUING>                            (2,493)                 (6,251)                (10,658)
<DISCONTINUED>                                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0
<CHANGES>                                            0                       0                       0
<NET-INCOME>                                   (2,493)                 (6,251)                (10,658)
<EPS-PRIMARY>                                   (0.26)                  (0.65)                  (1.10)
<EPS-DILUTED>                                   (0.26)                  (0.65)                  (1.10)