<ARTICLE> 5
<MULTIPLIER> 1,000
       
                             
<PERIOD-TYPE>                   9-MOS
<FISCAL-YEAR-END>                          APR-30-1997
<PERIOD-START>                             MAY-01-1996
<PERIOD-END>                               JAN-31-1997
<CASH>                                           8,862
<SECURITIES>                                    25,451
<RECEIVABLES>                                   15,266
<ALLOWANCES>                                       332
<INVENTORY>                                     12,036
<CURRENT-ASSETS>                                64,323
<PP&E>                                          33,999
<DEPRECIATION>                                  16,296
<TOTAL-ASSETS>                                  88,383
<CURRENT-LIABILITIES>                           13,110
<BONDS>                                              0
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                            12
<OTHER-SE>                                      73,303
<TOTAL-LIABILITY-AND-EQUITY>                    88,383
<SALES>                                         61,093
<TOTAL-REVENUES>                                61,093
<CGS>                                           31,586
<TOTAL-COSTS>                                   31,586
<OTHER-EXPENSES>                                 9,584<F1>
<LOSS-PROVISION>                                    45<F2>
<INTEREST-EXPENSE>                                   8
<INCOME-PRETAX>                                  8,769
<INCOME-TAX>                                     2,747
<INCOME-CONTINUING>                              6,022
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0 
<CHANGES>                                            0
<NET-INCOME>                                     6,022
<EPS-PRIMARY>                                      .48
<EPS-DILUTED>                                      .48
<FN>
<F1>RESEARCH AND DEVELOPMENT EXPENSES
<F2>PROVISION FOR BAD DEBT
</FN>