<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<RESTATED>
<MULTIPLIER>1,000

<S>                             <C>                     <C>                     <C>                     <C>
<C>
<PERIOD-TYPE>                   YEAR                   YEAR                   3-MOS                   3-MOS
3-MOS
<FISCAL-YEAR-END>                          DEC-31-1996             DEC-31-1995             MAR-31-1996             JUN-30-1996
             SEP-30-1996
<PERIOD-START>                             JAN-01-1996             JAN-01-1995             JAN-01-1996             APR-01-1996
             JUL-01-1996
<PERIOD-END>                               DEC-31-1996             DEC-31-1995             MAR-31-1996             JUN-30-1996
             SEP-30-1996
<CASH>                                          35,874                  50,633                  30,665                  31,848
                  24,758
<SECURITIES>                                         0                       0                  18,570                  11,757
                  12,751
<RECEIVABLES>                                    7,935                   8,111                   8,177                   9,880
                   8,393
<ALLOWANCES>                                     (348)                   (308)                   (294)                   (550)
                   (519)
<INVENTORY>                                      7,139                   5,256                   5,113                   6,060
                   6,356
<CURRENT-ASSETS>                                51,079                  64,081                  62,651                  59,690
                  52,275
<PP&E>                                           7,268                   4,221                   4,780                   5,320
                   6,220
<DEPRECIATION>                                 (2,698)                 (1,982)                 (2,143)                 (2,410)
                 (2,681)
<TOTAL-ASSETS>                                  55,692                  66,672                  65,613                  62,961
                  56,175
<CURRENT-LIABILITIES>                            6,742                   5,821                   5,459                   5,237
                   5,978
<BONDS>                                              0                       0                       0                       0
                       0
<PREFERRED-MANDATORY>                                0                   5,591                       0                       0
                       0
<PREFERRED>                                          0                       0                       0                       0
                       0
<COMMON>                                            17                      16                      16                      16
                      19
<OTHER-SE>                                      48,786                  54,846                  59,723                  57,301
                  50,021
<TOTAL-LIABILITY-AND-EQUITY>                    55,692                  66,672                  65,613                  62,961
                  56,175
<SALES>                                         36,346                  34,933                   9,095                   7,570
                   9,251
<TOTAL-REVENUES>                                36,346                  34,933                   9,095                   7,570
                   9,251
<CGS>                                           19,995                  17,584                   5,367                   4,109
                   4,976
<TOTAL-COSTS>                                   19,995                  17,584                   5,367                   4,109
                   4,976
<OTHER-EXPENSES>                                27,966                  19,755                   5,926                   6,549
                   8,271
<LOSS-PROVISION>                                   420                     158                       9                     275
                     100
<INTEREST-EXPENSE>                                  64                     114                      29                      34
                      29
<INCOME-PRETAX>                                (9,431)                 (1,945)                 (1,573)                 (2,513)
                 (3,481)
<INCOME-TAX>                                         2                      45                       0                       0
                       2
<INCOME-CONTINUING>                            (9,433)                 (1,990)                 (1,573)                 (2,513)
                 (3,483)
<DISCONTINUED>                                       0                       0                       0                       0
                       0
<EXTRAORDINARY>                                      0                       0                       0                       0
                       0
<CHANGES>                                            0                       0                       0                       0
                       0
<NET-INCOME>                                   (9,433)                 (1,990)                 (1,573)                 (2,513)
                 (3,483)
<EPS-PRIMARY>                                   (0.61)                  (0.46)                  (0.12)                  (0.17)
                  (0.23)
<EPS-DILUTED>                                   (0.61)                  (0.46)                  (0.12)                  (0.17)
                  (0.23)


</TABLE>