Marketable Securities - Summary of Available-for-Sale Debt Securities by Asset Type (Detail) - USD ($) $ in Thousands	May 31, 2024	May 31, 2023
Debt Securities, Available-for-sale [Line Items]
Available-for-Sale Debt Securities, Amortized Cost	$ 28,484	$ 28,988
Available-for-Sale Debt Securities, Gross Unrealized Gains	9	29
Available-for-Sale Debt Securities, Gross Unrealized Losses	(1,796)	(1,855)
Available-for-Sale Debt Securities, Fair Value (Net Carrying Amount)	26,697	27,162
U.S. Treasury and other government
Debt Securities, Available-for-sale [Line Items]
Available-for-Sale Debt Securities, Amortized Cost	28,338	28,841
Available-for-Sale Debt Securities, Gross Unrealized Gains	5	23
Available-for-Sale Debt Securities, Gross Unrealized Losses	(1,784)	(1,843)
Available-for-Sale Debt Securities, Fair Value (Net Carrying Amount)	26,559	27,021
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Available-for-Sale Debt Securities, Amortized Cost	146	147
Available-for-Sale Debt Securities, Gross Unrealized Gains	4	6
Available-for-Sale Debt Securities, Gross Unrealized Losses	(12)	(12)
Available-for-Sale Debt Securities, Fair Value (Net Carrying Amount)	$ 138	$ 141