Income Taxes - Effective Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2019
Income Tax Disclosure [Abstract]
Expected benefit at federal statutory rate	$ (11,628)	$ (14,489)	$ (6,947)
State tax expense—net of federal benefit	286	113	2
Impact of foreign operations	(299)	85	306
Federal research and development credit	(694)	(530)	(389)
Change in valuation allowance	30,587	14,837	6,587
Stock-based compensation	(17,667)	(23)	337
Meals and entertainment	35	242	207
Other permanent items	84	145	163
Provision for income taxes	$ 704	$ 380	$ 266

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

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Amount 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 increase (decrease) in the valuation allowance for deferred tax assets.

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The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations.

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