<TABLE> <S> <C>

<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE AUDITED
FINANCIAL STATEMENTS FILED IN THE COMPANY'S ANNUAL REPORT ON FORM 10-K AND IS
QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH AUDITED FINANCIAL STATEMENTS.
</LEGEND>
<MULTIPLIER> 1,000
       
<S>                             <C>                     <C>
<PERIOD-TYPE>                   6-MOS                   6-MOS
<FISCAL-YEAR-END>                          DEC-31-1997             DEC-31-1996
<PERIOD-START>                             APR-01-1997             APR-01-1996
<PERIOD-END>                               JUN-30-1997             JUN-30-1996
<CASH>                                           5,970                      98
<SECURITIES>                                     5,463                   7,574
<RECEIVABLES>                                    1,902                     664
<ALLOWANCES>                                         0                       0
<INVENTORY>                                          0                       0
<CURRENT-ASSETS>                                13,433                   8,656
<PP&E>                                           6,768                   5,666
<DEPRECIATION>                                   4,923                   3,957
<TOTAL-ASSETS>                                  15,314                  10,401
<CURRENT-LIABILITIES>                            2,431                   1,473
<BONDS>                                          1,340                   1,176
<PREFERRED-MANDATORY>                                0                       0
<PREFERRED>                                          0                       0
<COMMON>                                        58,242                  48,140
<OTHER-SE>                                    (46,081)                (39,666)
<TOTAL-LIABILITY-AND-EQUITY>                    12,160                   8,474
<SALES>                                              0                       0
<TOTAL-REVENUES>                                 1,471                     759
<CGS>                                                0                       0
<TOTAL-COSTS>                                    3,531                   2,501
<OTHER-EXPENSES>                                     0                       0
<LOSS-PROVISION>                                     0                       0
<INTEREST-EXPENSE>                                  61                      44
<INCOME-PRETAX>                                (2,121)                 (1,786)
<INCOME-TAX>                                         0                       0
<INCOME-CONTINUING>                            (2,121)                 (1,786)
<DISCONTINUED>                                       0                       0
<EXTRAORDINARY>                                      0                       0
<CHANGES>                                            0                       0
<NET-INCOME>                                   (2,121)                 (1,786)
<EPS-PRIMARY>                                   (0.11)                  (0.12)
<EPS-DILUTED>                                   (0.11)                  (0.12)
        

</TABLE>