Share-Based Compensation - Summary of Assumptions Applied to Establish Fair Value of Options Granted Using Black-Scholes Option Pricing Model (Details) - $ / shares	12 Months Ended
Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate	0.36%	1.38%	2.00%
Expected volatility	76.00%	73.00%	75.00%
Expected forfeiture rate	17.00%	12.00%	12.00%
Black-Scholes value of each option	$ 15.24	$ 19.83	$ 24.98
RIV Capital Share Based Compensation Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate		1.40%	1.70%
Expected volatility		70.00%	70.00%
Black-Scholes value of each option		$ 1.69	$ 1.80
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected life of options (years)	1 year	3 years	2 years
Minimum \| RIV Capital Share Based Compensation Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected life of options (years)		3 years	4 months 24 days
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected life of options (years)	7 years	5 years	5 years
Maximum \| RIV Capital Share Based Compensation Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected life of options (years)		4 years	4 years

Share-based compensation arrangement by share-based payment award fair value assumptions expected forfeiture rate.

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- Definition

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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- Definition

Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ 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
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.D.2)
-URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809

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