Convertible Instruments and Accrued Interest - Outstanding Balance (Details) - USD ($) $ in Thousands	Aug. 31, 2024	May 31, 2024
Debt Instrument
Convertible notes payable outstanding principal	$ 29,200	$ 30,200
Less: Unamortized debt discount and issuance costs	(282)	(407)
Convertible notes payable, net	28,918	29,793
Accrued interest on convertible notes	16,392	15,227
Outstanding convertible notes payable, net and accrued interest	45,310	45,020
Long-term Convertible Note - April 2, 2021 Note
Debt Instrument
Convertible notes payable outstanding principal	2,831	2,831
Less: Unamortized debt discount and issuance costs	(30)	(45)
Convertible notes payable, net	2,801	2,786
Accrued interest on convertible notes	4,828	4,634
Outstanding convertible notes payable, net and accrued interest	7,629	7,420
Long-term Convertible Note - April 23, 2021 Note
Debt Instrument
Convertible notes payable outstanding principal	26,369	27,369
Less: Unamortized debt discount and issuance costs	(252)	(362)
Convertible notes payable, net	26,117	27,007
Accrued interest on convertible notes	11,564	10,593
Outstanding convertible notes payable, net and accrued interest	$ 37,681	$ 37,600