FAIR VALUE OF FINANCIAL INSTRUMENTS (Details 1) - USD ($) $ in Thousands	Nov. 30, 2023	May 31, 2023	Nov. 30, 2022	May 31, 2022
Total cash and cash equivalents	$ 50,514	$ 30,054
Total cash, cash equivalents and investments	50,664	30,204	$ 18,954	$ 31,564
Short-term Investments	0	17,853
Short-term Investments	0	(17,853)
Cost [Member]
Cash	4,058	3,182
Total cash and cash equivalents	50,514	30,054
Total cash, cash equivalents and investments	50,664	48,074
Cost [Member] | Money Market Funds
Cash equivalents	46,456	26,872
Long-term investments	150	150
Cost [Member] | U S Treasury Securities [Member]
Short-term Investments		17,870
Short-term Investments		(17,870)
Gross Unrealized Loss
Cash	0	0
Total cash and cash equivalents	0	0
Total cash, cash equivalents and investments	0	(17)
Gross Unrealized Loss | Money Market Funds
Cash equivalents	0	0
Long-term investments	0	0
Gross Unrealized Loss | U S Treasury Securities [Member]
Short-term Investments		17
Short-term Investments		(17)
Estimated Fair Value [Member]
Cash	4,058	3,182
Total cash and cash equivalents	50,514	30,054
Total cash, cash equivalents and investments	50,664	48,057
Estimated Fair Value [Member] | Money Market Funds
Cash equivalents	46,456	26,872
Long-term investments	$ 150	150
Estimated Fair Value [Member] | U S Treasury Securities [Member]
Short-term Investments		17,853
Short-term Investments		$ (17,853)