<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<RESTATED>
<MULTIPLIER> 1,000

<S>                             <C>                     <C>                     <C>
<PERIOD-TYPE>                   3-MOS                   6-MOS                   9-MOS
<FISCAL-YEAR-END>                          DEC-31-1997             DEC-31-1997             DEC-31-1997
<PERIOD-END>                               MAR-31-1997             JUN-30-1997             SEP-30-1997
<CASH>                                             393                     861                   1,431
<SECURITIES>                                    28,245                  27,460                  24,355
<RECEIVABLES>                                    1,412                     436                     602
<ALLOWANCES>                                         0                       0                       0
<INVENTORY>                                         85                      91                      83
<CURRENT-ASSETS>                                30,926                  29,485                  26,955
<PP&E>                                           4,333                   4,649                   4,790
<DEPRECIATION>                                   3,224                   3,285                   3,434
<TOTAL-ASSETS>                                  32,035                  30,849                  28,311
<CURRENT-LIABILITIES>                            5,335                   6,135                   4,540
<BONDS>                                              0                       0                       0
<PREFERRED-MANDATORY>                                0                       0                       0
<PREFERRED>                                          1                       1                       1
<COMMON>                                            14                      14                      14
<OTHER-SE>                                      26,685                  24,699                  23,756
<TOTAL-LIABILITY-AND-EQUITY>                    32,035                  30,849                  28,311
<SALES>                                             10                     163                     240
<TOTAL-REVENUES>                                 4,971                   6,639                   8,493
<CGS>                                                4                      78                     130
<TOTAL-COSTS>                                    3,201                   7,359                  10,632
<OTHER-EXPENSES>                                     0                       0                       0
<LOSS-PROVISION>                                     0                       0                       0
<INTEREST-EXPENSE>                                   0                       0                       0
<INCOME-PRETAX>                                  2,158                     (5)                   (985)
<INCOME-TAX>                                         0                       0                       0
<INCOME-CONTINUING>                              2,158                     (5)                   (985)
<DISCONTINUED>                                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0
<CHANGES>                                            0                       0                       0
<NET-INCOME>                                     2,158                     (5)                   (985)
<EPS-PRIMARY>                                      .15                     .00                   (.07)
<EPS-DILUTED>                                      .14                     .00                   (.07)


</TABLE>