<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<RESTATED> 
       
<S>                             <C>                     <C>                     <C>
<PERIOD-TYPE>                   9-MOS                   6-MOS                   3-MOS
<FISCAL-YEAR-END>                          APR-30-1998             APR-30-1998             APR-30-1997
<PERIOD-END>                               JAN-31-1998             OCT-31-1997             JUL-31-1997
<CASH>                                         964,120               1,571,101               2,851,311
<SECURITIES>                                         0                       0                       0
<RECEIVABLES>                               10,846,053               9,118,014              10,025,086
<ALLOWANCES>                                   265,602                 346,930                 245,764
<INVENTORY>                                 17,664,204              15,120,749              15,059,097
<CURRENT-ASSETS>                            31,350,195              27,719,093              30,139,372
<PP&E>                                      19,042,064              16,711,806              16,413,004
<DEPRECIATION>                              10,122,070               9,206,373               8,763,824
<TOTAL-ASSETS>                              51,268,862              44,239,036              47,355,963
<CURRENT-LIABILITIES>                       11,166,842               9,438,788              11,094,406
<BONDS>                                              0                       0                       0
<PREFERRED-MANDATORY>                                0                       0                       0
<PREFERRED>                                  5,650,000               5,650,000               5,650,000
<COMMON>                                         7,036                   5,984                   5,815
<OTHER-SE>                                  27,198,871              18,566,832              16,855,318
<TOTAL-LIABILITY-AND-EQUITY>                51,268,862              44,239,036              47,355,963
<SALES>                                     44,716,184              29,880,881              14,151,086
<TOTAL-REVENUES>                            51,444,821              34,451,586              16,289,323
<CGS>                                       27,232,314              18,574,808               8,819,156
<TOTAL-COSTS>                               46,400,444              31,403,058              14,974,619
<OTHER-EXPENSES>                                     0                       0                       0
<LOSS-PROVISION>                                     0                       0                       0
<INTEREST-EXPENSE>                             686,056                 501,925                 279,648
<INCOME-PRETAX>                              4,358,321               2,546,603               1,035,056
<INCOME-TAX>                                   740,915                 392,667                 139,430
<INCOME-CONTINUING>                          3,325,739               1,979,973                 840,371
<DISCONTINUED>                                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0
<CHANGES>                                            0                       0                       0
<NET-INCOME>                                 2,879,491               1,682,474                 691,621
<EPS-PRIMARY>                                     0.47                    0.29                    0.12
<EPS-DILUTED>                                     0.42                    0.26                    0.11
        

</TABLE>