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STOCK-BASED COMPENSATION - Additional Information (Details) $ in Thousands | 1 Months Ended | 12 Months Ended | 13 Months Ended
--- | --- | --- | ---
Apr. 30, 2019 person shares | Apr. 30, 2018 person shares | Jan. 31, 2020 USD ($) shares | Jan. 31, 2019 USD ($) | Jan. 31, 2018 USD ($) | Apr. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award |  |  |  |  |  |
Percentage reduction in the aggregate fair value of stock option |  |  | 88.50% |  |  |
Stock compensation expense |  |  | $ 2,131 | $ 1,645 | $ 4,651 |
Unrecognized compensation cost |  |  | 4,400 |  |  |
Intrinsic value of outstanding stock options |  |  | 5,100 |  |  |
Intrinsic value of exercisable stock options |  |  | $ 4,600 |  |  |
Period used for calculations |  |  | 5 years |  |  |
Company's expense for defined contribution savings plans |  |  | $ 1,700 | 2,400 | 2,800 |
Minimum |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award |  |  |  |  |  |
Deferred period |  |  | 5 years |  |  |
Maximum |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award |  |  |  |  |  |
Deferred period |  |  | 7 years |  |  |
Stock Plan |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award |  |  |  |  |  |
Number of shares of common stock available for award | shares |  |  | 381,833 |  |  |
Stock Options Plans |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award |  |  |  |  |  |
Number of shares of common stock available for award | shares |  |  | 1,700,000 |  |  |
Compensation expense recognize, period |  |  | 3 years |  |  |
Intrinsic value of the stock options exercised |  |  | $ 1,400 | $ 200 | $ 3,600 |
Stock Options Plans | Stock Plan |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award |  |  |  |  |  |
Incentive stock option award maximum expiration period |  |  | 10 years |  |  |
Period to become exercisable |  |  | 1 year |  |  |
Senior executives | Performance-based restricted stock units | Stock Plan |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award |  |  |  |  |  |
Period to become exercisable |  |  |  |  |  | 3 years
Number of executives | person | 2 | 2 |  |  |  |
Senior executives | Performance-based restricted stock units | Stock Plan | Maximum |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award |  |  |  |  |  |
Number of shares awarded | shares | 36,000 | 36,000 |  |  |  |

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- Definition The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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