<TABLE> <S> <C>
<PAGE>
<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE
FINANCIAL STATEMENTS OF ESI AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO
SUCH FINANCIAL STATEMENTS.
</LEGEND>
<S> <C>
<PERIOD-TYPE> 9-MOS
<FISCAL-YEAR-END> DEC-31-2000
<PERIOD-START> JAN-01-2000
<PERIOD-END> SEP-30-2000
<CASH> 8,749,042
<SECURITIES> 3,681,872
<RECEIVABLES> 2,953,599
<ALLOWANCES> 0
<INVENTORY> 3,906,066
<CURRENT-ASSETS> 19,779,634
<PP&E> 6,293,404
<DEPRECIATION> (3,294,706)
<TOTAL-ASSETS> 23,465,974
<CURRENT-LIABILITIES> 10,810,657
<BONDS> 0
0
0
<COMMON> 122,347
<OTHER-SE> 71,764,665
<TOTAL-LIABILITY-AND-EQUITY> 23,465,974
<SALES> 10,194,326
<TOTAL-REVENUES> 10,194,326
<CGS> 5,329,527
<TOTAL-COSTS> 5,329,527
<OTHER-EXPENSES> 13,199,117
<LOSS-PROVISION> 0
<INTEREST-EXPENSE> 507,786
<INCOME-PRETAX> (8,430,911)
<INCOME-TAX> 0
<INCOME-CONTINUING> 0
<DISCONTINUED> 0
<EXTRAORDINARY> 0
<CHANGES> 0
<NET-INCOME> (8,430,911)
<EPS-BASIC> (.78)
<EPS-DILUTED> (.78)
</TABLE>