<TABLE> <S> <C>

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

<S>                             <C>                     <C>                     <C>
<PERIOD-TYPE>                   3-MOS                   3-MOS                   3-MOS
<FISCAL-YEAR-END>                          MAR-31-1997             JUN-30-1997             SEP-30-1997
<PERIOD-START>                             JAN-01-1997             APR-01-1997             JUL-01-1997
<PERIOD-END>                               MAR-31-1997             JUN-30-1997             SEP-30-1997
<CASH>                                          26,276                  27,133                  23,777
<SECURITIES>                                     3,935                       0                       0
<RECEIVABLES>                                    5,382                   5,856                   5,066
<ALLOWANCES>                                       411                     321                     280
<INVENTORY>                                      7,167                   7,271                   8,005
<CURRENT-ASSETS>                                43,146                  40,536                  37,216
<PP&E>                                           8,113                   8,270                   8,433
<DEPRECIATION>                                 (3,103)                 (3,519)                 (3,947)
<TOTAL-ASSETS>                                  48,199                  45,331                  41,746
<CURRENT-LIABILITIES>                            5,145                   5,178                   6,057
<BONDS>                                              0                       0                       0
<PREFERRED-MANDATORY>                                0                       0                       0
<PREFERRED>                                          0                       0                       0
<COMMON>                                            17                      17                      17
<OTHER-SE>                                      42,895                  40,006                  35,550
<TOTAL-LIABILITY-AND-EQUITY>                    48,199                  45,331                  41,746
<SALES>                                          5,082                   6,291                   5,675
<TOTAL-REVENUES>                                 5,082                   6,291                   5,675
<CGS>                                            3,469                   3,826                   3,623
<TOTAL-COSTS>                                    3,469                   3,826                   3,623
<OTHER-EXPENSES>                                 8,250                   5,790                   6,984
<LOSS-PROVISION>                                   115                      32                     (7)
<INTEREST-EXPENSE>                                  21                      11                      10
<INCOME-PRETAX>                                (6,179)                 (2,983)                 (4,587)
<INCOME-TAX>                                         0                       0                       0
<INCOME-CONTINUING>                            (6,179)                 (2,983)                 (4,587)
<DISCONTINUED>                                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0
<CHANGES>                                            0                       0                       0
<NET-INCOME>                                   (6,179)                 (2,983)                 (4,587)
<EPS-PRIMARY>                                   (0.36)                  (0.17)                  (0.27)
<EPS-DILUTED>                                   (0.36)                  (0.17)                  (0.27)


</TABLE>