<TABLE> <S> <C>

<PAGE>

<ARTICLE> 5
<RESTATED>
<MULTIPLIER> 1,000
       
<S>                          <C>                        <C>                     <C>                     <C>
<PERIOD-TYPE>               12-MOS                      9-MOS                   6-MOS                   3-MOS
<FISCAL-YEAR-END>                       MAY-31-1997                MAY-31-1997             MAY-31-1997             MAY-31-1997
<PERIOD-START>                          JUN-01-1996                JUN-01-1996             JUN-01-1996             JUN-01-1996
<PERIOD-END>                            MAY-31-1997                MAR-01-1997             NOV-30-1996             AUG-31-1996
<CASH>                                       12,203                     12,868                  14,090                  14,427
<SECURITIES>                                      0                          0                       0                       0
<RECEIVABLES>                                 7,181                      6,866                   5,870                   8,001
<ALLOWANCES>                                    149                          0                       0                     116
<INVENTORY>                                   8,700                      9,672                  10,305                  11,446
<CURRENT-ASSETS>                             31,113                     31,610                  32,427                  34,996
<PP&E>                                       19,916                     19,422                  19,214                  19,114
<DEPRECIATION>                                9,767                      9,120                   8,506                   7,872
<TOTAL-ASSETS>                               50,964                     52,053                  53,465                  56,669
<CURRENT-LIABILITIES>                         7,417                      7,506                   7,923                   9,369
<BONDS>                                           0                          0                       0                       0
<PREFERRED-MANDATORY>                             0                          0                       0                       0
<PREFERRED>                                       0                          0                       0                       0
<COMMON>                                        658                        656                     655                     658
<OTHER-SE>                                   42,003                     42,839                  43,879                  46,642
<TOTAL-LIABILITY-AND-EQUITY>                 50,964                     52,053                  53,465                  56,669
<SALES>                                      43,271                     30,914                  21,290                  13,288
<TOTAL-REVENUES>                             43,271                     30,914                  21,290                  13,288
<CGS>                                        33,582                     23,796                  16,297                   8,670
<TOTAL-COSTS>                                50,512                     36,524                  25,421                  13,321
<OTHER-EXPENSES>                                  0                         60                       0                       0
<LOSS-PROVISION>                                  0                          0                       0                       0
<INTEREST-EXPENSE>                              148                         41                      26                      11
<INCOME-PRETAX>                             (6,528)                    (5,082)                 (3,759)                     185
<INCOME-TAX>                                (2,220)                    (1,626)                 (1,203)                      83
<INCOME-CONTINUING>                         (4,308)                    (3,456)                 (2,556)                     102
<DISCONTINUED>                                    0                          0                       0                       0
<EXTRAORDINARY>                                   0                          0                       0                       0
<CHANGES>                                         0                          0                       0                       0
<NET-INCOME>                                (4,308)                    (3,456)                 (2,556)                     102
<EPS-PRIMARY>                                (0.99)                     (0.79)                  (0.57)                    0.02
<EPS-DILUTED>                                (0.99)                     (0.79)                  (0.57)                    0.02
        


</TABLE>