<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<RESTATED>

<S>                             <C>                     <C>                     <C>
<PERIOD-TYPE>                   12-MOS                   12-MOS                   12-MOS
<FISCAL-YEAR-END>                          DEC-31-1997             DEC-31-1996             DEC-31-1995
<PERIOD-START>                             JAN-01-1997             JAN-01-1996             JAN-01-1995
<PERIOD-END>                               DEC-31-1997             DEC-31-1996             DEC-31-1995
<CASH>                                      57,830,000               8,611,000               2,219,000
<SECURITIES>                                         0              38,300,000                       0
<RECEIVABLES>                                4,235,000                       0                       0
<ALLOWANCES>                                         0                       0                       0
<INVENTORY>                                  2,227,000                       0               2,625,000
<CURRENT-ASSETS>                            65,214,000              47,259,000                 148,000
<PP&E>                                      16,415,000               2,843,000                  40,000
<DEPRECIATION>                                 951,000                 195,000               2,958,000
<TOTAL-ASSETS>                             121,947,000              51,692,000               2,234,000
<CURRENT-LIABILITIES>                        3,860,000               2,411,000                       0
<BONDS>                                              0                       0                       0
<PREFERRED-MANDATORY>                                0                       0                       0
<PREFERRED>                                          0                       0                       0
<COMMON>                                        67,000                  54,000                  20,000
<OTHER-SE>                                 182,539,000              46,156,000                 260,000
<TOTAL-LIABILITY-AND-EQUITY>               127,947,000              51,692,000               2,958,000
<SALES>                                      5,002,000                       0                       0
<TOTAL-REVENUES>                             5,002,000                       0                       0
<CGS>                                        4,130,000                       0                       0
<TOTAL-COSTS>                               62,057,000              21,734,000               5,112,000
<OTHER-EXPENSES>                           (5,441,000)             (1,874,000)                 128,000
<LOSS-PROVISION>                                     0                       0                       0
<INTEREST-EXPENSE>                             121,000                       0                       0
<INCOME-PRETAX>                           (56,199,000)            (19,860,000)             (5,240,000)
<INCOME-TAX>                                         0                       0                       0
<INCOME-CONTINUING>                                  0                       0                       0
<DISCONTINUED>                                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0
<CHANGES>                                            0                       0                       0
<NET-INCOME>                              (56,199,000)            (19,860,000)             (5,240,000)
<EPS-PRIMARY>                                   (1.01)                   (.50)<F1>               (.27)<F1>
<EPS-DILUTED>                                   (1.02)                   (.50)<F1>               (.27)<F1>

<FN>
<F1> 1996 and 1995 presented to show earnings per share in accordance with
     Statement of Financial Accounting Standards No. 128, Earnings per share.
</FN>

</TABLE>