Stock Option and bonus plans (Details) - $ / shares	12 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Stock Option And Bonus Plans Details
Number of Options	425,000	850,000	850,000
Exercised	(425,000)
Weighted Average Exercise Price	$ 1.50	$ 1.50	$ 1.50

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- Definition

Number of options outstanding, including both vested and non-vested options.

+ References

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- Definition

Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

+ References

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- Definition

Number of share options (or share units) exercised during the current period.

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