<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE
CONDENSED CONSOLIDATED BALANCE SHEETS AND CONDENSED CONSOLIDATED STATEMENTS OF
OPERATIONS FOUND ON PAGES 3 AND 4 OF THE COMPANY'S FORM 10-Q FOR THE
YEAR-TO-DATE, 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                   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>                                          22,370                  59,353                  62,983
<SECURITIES>                                    51,584                  79,061                  63,343
<RECEIVABLES>                                    2,983                   4,355                   6,298
<ALLOWANCES>                                       380                     669                     848
<INVENTORY>                                      2,911                   4,212                   3,465
<CURRENT-ASSETS>                                80,882                 149,160                 137,333
<PP&E>                                           9,460                  12,535                  16,680
<DEPRECIATION>                                   2,130                   2,757                   3,448
<TOTAL-ASSETS>                                  89,434                 163,284                 154,977
<CURRENT-LIABILITIES>                            6,226                   7,484                  12,285
<BONDS>                                              0                       0                       0
<PREFERRED-MANDATORY>                                0                       0                       0
<PREFERRED>                                          0                       0                       0
<COMMON>                                            24                      25                      25
<OTHER-SE>                                      78,708                  65,509                  52,720
<TOTAL-LIABILITY-AND-EQUITY>                    89,434                 163,284                 154,977
<SALES>                                          3,216                   7,868                  15,019
<TOTAL-REVENUES>                                 3,216                   7,868                  15,019
<CGS>                                            2,721                   6,342                  11,191
<TOTAL-COSTS>                                    2,721                   6,342                  11,191
<OTHER-EXPENSES>                                     0                       0                       0
<LOSS-PROVISION>                                   117                     186                     282
<INTEREST-EXPENSE>                                  81                   1,203                   3,000
<INCOME-PRETAX>                               (11,948)                (26,550)                (39,479)
<INCOME-TAX>                                         0                       0                       0
<INCOME-CONTINUING>                           (11,948)                (26,550)                (39,479)
<DISCONTINUED>                                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0
<CHANGES>                                            0                       0                       0
<NET-INCOME>                                  (11,948)                (26,550)                (39,479)
<EPS-PRIMARY>                                   (0.54)                  (1.20)                  (1.77)
<EPS-DILUTED>                                   (0.54)                  (1.20)                  (1.77)


</TABLE>