Net (Loss) Income Per Share - Calculation of Net (Loss) Income Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Feb. 29, 2024	Feb. 28, 2023	Feb. 29, 2024	Feb. 28, 2023
Earnings Per Share [Line Items]
Numerator for basic and diluted net (loss) income per share: - Net (loss) income attributable to Neogen	$ (2,022)	$ 8,190	$ (4,006)	$ (28,442)
Denominator for basic net (loss) income per share - Weighted average shares	216,597,777	216,217,702	216,438,643	179,666,118
Effect of dilutive stock options and RSUs		181,301
Denominator for diluted net (loss) income per share	216,597,777	216,399,003	216,438,643	179,666,118
Net (loss) income per share:
Basic	$ (0.01)	$ 0.04	$ (0.02)	$ (0.16)
Diluted	$ (0.01)	$ 0.04	$ (0.02)	$ (0.16)