Income Taxes - Schedule of Effective Federal Statutory Rate and Provision for Income Taxes (Detail)	12 Months Ended
Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2020
Income Tax Disclosure [Abstract]
Federal statutory rate	21.00%	21.00%	21.00%
Effect of:
State taxes, net of federal benefits	3.50%	3.00%	3.00%
Stock-based compensation	3.80%	(1.50%)	(0.40%)
Research and development credits, net of ASC 740-10	2.50%	2.40%	5.10%
Permanent items	(4.40%)	(2.40%)	(4.00%)
Foreign taxes	0.00%	0.20%	0.40%
Intraperiod allocation	0.00%	0.00%	1.50%
Other	0.50%	0.70%	0.70%
Valuation allowance	(27.00%)	(23.70%)	(27.50%)
Effective tax rate	(0.10%)	(0.30%)	(0.20%)

Effective Income Tax Rate Reconciliation, Intraperiod Tax Allocation

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Effective Income Tax Rate Reconciliation, Permanent Items, Percent

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 12
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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
-Topic 740
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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to changes in the valuation allowance for deferred tax assets.

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to statutory income tax expense (benefit) outside of the country of domicile.

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Percentage of difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying domestic federal statutory income tax rate to pretax income (loss) from continuing operation, attributable to nondeductible expense for share-based payment arrangement.

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to state and local income tax expense (benefit), net of federal tax expense (benefit).

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