Common Stock and Stock Plans - Summary of Employee Stock Options and Employee Stock Purchase Plan Weighted Average Assumptions (Detail)	12 Months Ended
Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Volatility	39.10%	27.90%	27.90%
Risk-free interest rate	0.20%	1.30%	2.80%
Dividend yield	0.00%	0.00%	0.00%
Expected life	5 years	5 years	5 years
TSR Performance Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Volatility	39.80%	27.70%	28.20%
Risk-free interest rate	0.40%	1.70%	2.80%
Dividend yield	0.00%	0.00%	0.00%
Expected life	5 years	5 years	5 years
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Volatility	64.80%	24.60%	32.80%
Risk-free interest rate	0.10%	1.80%	2.40%
Dividend yield	0.00%	0.00%	0.00%
Expected life	6 months	6 months	6 months

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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- Definition

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

+ References

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- Definition

Rate of weighted-average expected volatility for award under share-based payment arrangement.

+ References

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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.

+ References

No definition available.

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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
-Subparagraph (f)(2)(i)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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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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