<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE
BALANCE SHEETS FOR SEPTEMBER 30, JUNE 30 AND MARCH 31, 1997 AND THE
STATEMENTS OF OPERATIONS FOR THE NINE MONTHS ENDED SEPTEMBER 30, THE
SIX MONTHS ENDED JUNE 30 AND THE THREE MONTHS ENDED MARCH 31, 1997 AND
IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<RESTATED>

<S>                             <C>                     <C>                     <C>
<PERIOD-TYPE>                   9-MOS                   6-MOS                   3-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>                               SEP-30-1997             JUN-30-1997             MAR-31-1997
<CASH>                                      12,062,710              10,642,034              17,241,057
<SECURITIES>                                 6,004,874               2,998,913                 897,856
<RECEIVABLES>                               14,553,553              14,273,250              11,845,573
<ALLOWANCES>                                 1,838,533               1,717,425               1,416,480
<INVENTORY>                                    462,073                 496,118                 703,195
<CURRENT-ASSETS>                            33,062,762              28,735,013              30,722,448
<PP&E>                                      11,693,149              10,370,828               8,811,015
<DEPRECIATION>                               3,821,779               3,480,521               3,147,757
<TOTAL-ASSETS>                              50,850,860              50,413,647              50,166,358
<CURRENT-LIABILITIES>                        2,300,574               2,358,821               2,683,914
<BONDS>                                              0                       0                       0
<PREFERRED-MANDATORY>                                0                       0                       0
<PREFERRED>                                          0                       0                       0
<COMMON>                                       102,009                 101,711                 101,540
<OTHER-SE>                                  48,151,887              47,560,950              46,866,941
<TOTAL-LIABILITY-AND-EQUITY>                50,850,860              50,413,647              50,166,358
<SALES>                                              0                       0                       0
<TOTAL-REVENUES>                            23,658,800              15,873,272               8,078,565
<CGS>                                                0                       0                       0
<TOTAL-COSTS>                                9,075,557               5,904,936               2,981,103
<OTHER-EXPENSES>                            12,126,366               8,065,952               3,893,131
<LOSS-PROVISION>                             1,226,239                 835,614                 406,283
<INTEREST-EXPENSE>                             125,598                  92,930                  50,580
<INCOME-PRETAX>                              2,363,222               1,841,414               1,201,084
<INCOME-TAX>                                         0                       0                       0
<INCOME-CONTINUING>                          2,363,222               1,841,414               1,201,084
<DISCONTINUED>                                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0
<CHANGES>                                            0                       0                       0
<NET-INCOME>                                 2,363,222               1,841,414               1,201,084
<EPS-PRIMARY>                                     0.23                    0.18                    0.12
<EPS-DILUTED>                                     0.21                    0.17                    0.11


</TABLE>