Marketable Securities - Summary of Fair Values of Company's Investments By Type (Detail) - USD ($) $ in Thousands	Jul. 31, 2022	Apr. 30, 2022
Marketable Securities [Line Items]
Amortized Cost	$ 105,228	$ 136,599
Unrealized Gains	15	2
Unrealized Losses	(1,031)	(1,131)
Estimated Fair Value	104,212	135,470
Corporate Debt Securities [Member]
Marketable Securities [Line Items]
Amortized Cost	89,149	112,997
Unrealized Gains	15	2
Unrealized Losses	(896)	(994)
Estimated Fair Value	88,268	112,005
Obligations of U.S. Government and Its Agencies [Member]
Marketable Securities [Line Items]
Amortized Cost	16,079	23,602
Unrealized Losses	(135)	(137)
Estimated Fair Value	$ 15,944	$ 23,465

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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