Stockholders' Equity (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	May 31, 2024 USD ($) $ / shares shares
Schedule summarizes stock option activity
Shares Outstanding at beginning of year (shares) | shares	2,206,549
Shares Granted (shares) | shares	455,527
Shares Exercised (shares) | shares	0
Shares Forfeited (shares) | shares	(198,975)
Shares Expired (shares) | shares	(300,118)
Shares Outstanding at end of year (shares) | shares	2,162,983
Shares Options exercisable at year-end (shares) | shares	1,317,662
Shares Options expected to vest in future periods (shares) | shares	845,321
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted average exercise price, Outstanding at beginning of year (usd per share) | $ / shares	$ 17.90
Weighted average exercise price Granted (usd per share) | $ / shares	8.92
Weighted average exercise price Exercised (usd per share) | $ / shares	0
Weighted average exercise price Forfeited (usd per share) | $ / shares	17.16
Weighted average exercise price Expired (usd per share) | $ / shares	16.33
Weighted average exercise price, Outstanding at end of year (usd per share) | $ / shares	16.29
Weighted average exercise price, Options exercisable at year end (usd per share) | $ / shares	17.44
Weighted average exercise price, Options expected to vest in future periods (usd per share) | $ / shares	$ 14.51
Weighted average remaining contractual life	6 years 6 months 7 days
Weighted average remaining contractual life, Option exercisable at year end	5 years 5 months 8 days
Weighted average remaining contractual life, Option expected to vest in future periods	8 years 2 months 12 days
Aggregate intrinsic value, Outstanding at end of year | $	$ 0
Aggregate intrinsic value, Options exercisable at year end | $	0
Aggregate intrinsic value, Option expected to vest in future periods | $	$ 0