<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<RESTATED> 
       
<S>                             <C>                     <C>                     <C>                     <C>
<PERIOD-TYPE>                   YEAR                   YEAR                   3-MOS                   9-MOS
<FISCAL-YEAR-END>                          MAR-31-1997             MAR-31-1996             MAR-31-1997             MAR-31-1997
<PERIOD-START>                             APR-01-1996             APR-01-1995             APR-01-1996              APR-1-1996
<PERIOD-END>                               MAR-31-1997             MAR-31-1996             JUN-30-1996             DEC-31-1996
<CASH>                                       2,677,278               9,803,777               9,501,830               2,516,613
<SECURITIES>                                24,995,229              28,052,742              26,425,295              27,959,825
<RECEIVABLES>                                1,529,959                       0               1,252,556               2,027,052
<ALLOWANCES>                                         0                       0                       0                       0
<INVENTORY>                                    743,531                 529,606                 541,644                 652,428
<CURRENT-ASSETS>                            30,225,891              39,583,918              38,021,607              33,631,308
<PP&E>                                       1,646,723               2,050,475               2,317,547               2,697,406
<DEPRECIATION>                                       0               1,068,353               1,207,551               1,266,722
<TOTAL-ASSETS>                              32,513,835              40,916,461              39,627,424              35,503,213
<CURRENT-LIABILITIES>                        2,903,014               1,905,218               2,142,903               3,052,466
<BONDS>                                        228,441                 510,789                 415,146                 228,077
<PREFERRED-MANDATORY>                                0                       0                       0                       0
<PREFERRED>                                          0                       0                       0                       0
<COMMON>                                         9,564                   9,502                   9,485                   9,519
<OTHER-SE>                                  29,372,816              38,490,952              37,059,891              32,213,151
<TOTAL-LIABILITY-AND-EQUITY>                32,513,835              40,916,461              39,627,424              35,503,213
<SALES>                                      4,455,805               2,457,087               1,500,175               3,427,097
<TOTAL-REVENUES>                             4,455,805               2,457,087               1,500,175               3,427,097
<CGS>                                        4,703,340               4,772,022               1,162,039               3,451,303
<TOTAL-COSTS>                               15,749,289              11,316,739               3,410,395              11,243,700
<OTHER-EXPENSES>                                     0                       0                       0                       0
<LOSS-PROVISION>                                     0                       0                       0                       0
<INTEREST-EXPENSE>                           1,635,889                 775,633                 438,315               1,330,186
<INCOME-PRETAX>                            (9,657,595)             (8,084,019)             (1,471,905)             (6,486,417)
<INCOME-TAX>                                         0                       0                       0                       0
<INCOME-CONTINUING>                        (9,657,595)             (8,084,019)             (1,471,905)             (6,486,417)
<DISCONTINUED>                                       0                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0                       0
<CHANGES>                                            0                       0                       0                       0
<NET-INCOME>                               (9,657,595)             (8,084,019)             (1,471,905)             (6,486,417)
<EPS-PRIMARY>                                   (1.02)                  (1.76)                   (.16)                   (.69)
<EPS-DILUTED>                                   (1.02)                  (1.76)                   (.16)                   (.69)
        

</TABLE>