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The Company and Its Accounting Policies - Additional Information (Detail) - USD ($) shares in Thousands, $ in Thousands |  | 12 Months Ended |
--- | --- | --- | ---
Apr. 01, 2019 | Mar. 31, 2020 | Mar. 31, 2019 | Mar. 31, 2018 | Jun. 24, 2019
Schedule Of Accounting Policies [Line Items] |  |  |  |  |
Minimum level of likelihood |  | 50.00% |  |  |
Description of sale of asset |  | The sale of the asset (disposal group) is probable, and transfer of the asset (disposal group) is expected to qualify for recognition as a completed sale within one year, except if events or circumstances beyond the Company's control extend the period of time required to sell the asset (disposal group) beyond one year; |  |  |
Research and development costs |  | $ 3,353 | $ 3,538 | $ 3,211 |
Antidilutive securities excluded from computation of earnings per share |  |  | 39 | 69 |
Interest paid |  | 12 | $ 12 | $ 12 |
Income taxes paid (refunded) |  | 139 | (73) | 1,916 |
Pension and other postretirement benefit adjustments, net of tax |  | 525 | 348 | (1,668) |
Issuance of treasury stock |  | 170 | 134 | 130 |
Capital expenditures |  | 162 | 85 | 0 |
Capital leases |  | 0 | 100 | 0 |
Right-of-use assets |  | 243 |  |  |
Lease liabilities |  | 235 |  |  |
Retained earnings |  | $ 91,389 | 93,847 |  |
Topic 842 [Member] |  |  |  |  |
Schedule Of Accounting Policies [Line Items] |  |  |  |  |
Right-of-use assets | $ 677 |  |  |  | $ 500
Lease liabilities | 732 |  |  |  | $ 500
Retained earnings | 80 |  |  |  |
Decrease in other current assets | 47 |  |  |  |
Decrease in deferred income tax liability | $ 22 |  |  |  |
Topic 842 [Member] | Held for Sale [Member] |  |  |  |  |
Schedule Of Accounting Policies [Line Items] |  |  |  |  |
Right-of-use assets |  |  | 500 |  |
Lease liabilities |  |  | $ 500 |  |
Retained Earnings [Member] |  |  |  |  |
Schedule Of Accounting Policies [Line Items] |  |  |  |  |
Amounts reclassified from accumulated other comprehensive loss to retained earnings |  |  |  | $ 1,828 |
Buildings and Leasehold Improvements [Member] |  |  |  |  |
Schedule Of Accounting Policies [Line Items] |  |  |  |  |
Estimated useful lives range |  | 40 years |  |  |
Minimum [Member] |  |  |  |  |
Schedule Of Accounting Policies [Line Items] |  |  |  |  |
Treasury with original maturities period |  | 3 months |  |  |
Minimum [Member] | Office Equipment [Member] |  |  |  |  |
Schedule Of Accounting Policies [Line Items] |  |  |  |  |
Estimated useful lives range |  | 5 years |  |  |
Minimum [Member] | Manufacturing Equipment [Member] |  |  |  |  |
Schedule Of Accounting Policies [Line Items] |  |  |  |  |
Estimated useful lives range |  | 8 years |  |  |
Maximum [Member] |  |  |  |  |
Schedule Of Accounting Policies [Line Items] |  |  |  |  |
Treasury with original maturities period |  | 1 year |  |  |
Investment maturity date range end |  | Jun. 25, 2020 |  |  |
Maximum [Member] | Topic 842 [Member] |  |  |  |  |
Schedule Of Accounting Policies [Line Items] |  |  |  |  |
Lease term |  | 12 months |  |  |
Maximum [Member] | Office Equipment [Member] |  |  |  |  |
Schedule Of Accounting Policies [Line Items] |  |  |  |  |
Estimated useful lives range |  | 8 years |  |  |
Maximum [Member] | Manufacturing Equipment [Member] |  |  |  |  |
Schedule Of Accounting Policies [Line Items] |  |  |  |  |
Estimated useful lives range |  | 25 years |  |  |

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