<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE BALANCE
SHEETS AS OF SEP-30-1997, JUN-30-1997 AND MAR-31-1997 AND THE RELATED STATEMENTS
OF OPERATIONS, SHAREHOLDERS' EQUITY AND CASH FLOWS FOR THE RESPECTIVE PERIODS
THEN ENDED AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH
FINANCIAL STATEMENTS.
</LEGEND>
<RESTATED>
<MULTIPLIER> 1,000

<S>                             <C>                     <C>                     <C>
<PERIOD-TYPE>                   3-MOS                   3-MOS                   3-MOS
<FISCAL-YEAR-END>                          DEC-31-1997             DEC-31-1997             DEC-31-1997
<PERIOD-START>                             JUL-01-1997             APR-01-1997             JAN-01-1997
<PERIOD-END>                               SEP-30-1997             JUN-30-1997             MAR-31-1997
<CASH>                                          11,373                  11,146                  12,748
<SECURITIES>                                         0                       0                       0
<RECEIVABLES>                                    3,660                   3,170                   2,554
<ALLOWANCES>                                         0                       0                       0
<INVENTORY>                                          0                       0                       0
<CURRENT-ASSETS>                                15,561                  14,841                  15,960
<PP&E>                                          14,572                  12,564                  11,266
<DEPRECIATION>                                   4,412                   3,856                   3,374
<TOTAL-ASSETS>                                  26,461                  24,181                  24,525
<CURRENT-LIABILITIES>                            3,488                   2,146                   2,446
<BONDS>                                              0                       0                       0
<PREFERRED-MANDATORY>                                0                       0                       0
<PREFERRED>                                          0                       0                       0
<COMMON>                                        37,202                  36,821                  36,734
<OTHER-SE>                                           0                       0                       0
<TOTAL-LIABILITY-AND-EQUITY>                    26,461                  24,181                  24,525
<SALES>                                              0                       0                       0
<TOTAL-REVENUES>                                 7,055                   5,468                   4,486
<CGS>                                                0                       0                       0
<TOTAL-COSTS>                                    6,372                   5,399                   4,938
<OTHER-EXPENSES>                                 (139)                    (34)                   (159)
<LOSS-PROVISION>                                     0                       0                       0
<INTEREST-EXPENSE>                                  77                      87                      98
<INCOME-PRETAX>                                    744                      16                   (391)
<INCOME-TAX>                                         0                       0                       0
<INCOME-CONTINUING>                                744                      16                   (391)
<DISCONTINUED>                                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0
<CHANGES>                                            0                       0                       0
<NET-INCOME>                                       744                      16                   (391)
<EPS-PRIMARY>                                    $0.07                   $0.00                 ($0.04)
<EPS-DILUTED>                                    $0.07                   $0.00                 ($0.04)


</TABLE>