Equity Awards - Expense and unrecognized (Details) - USD ($) $ in Thousands, shares in Millions  | 
3 Months Ended | ||||
|---|---|---|---|---|---|
Aug. 31, 2022  | 
Aug. 31, 2021  | 
||||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
| Compensation expense | $ 1,341 | $ 2,597 | [1] | ||
| Common stock warrants to purchase shares | 5.5 | ||||
| Surety Bond Backstop Agreement | |||||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
| Stock based compensation | $ 5,300 | 0 | |||
| Equity Instruments | General and Administrative Expenses | |||||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
| Compensation expense | $ 1,300 | $ 2,600 | |||
  | |||||
| X | ||||||||||
- Definition Amount of expense for award under share-based payment arrangement. Excludes amount capitalized. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
  | 
| X | ||||||||||
- Definition Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
  | 
| X | ||||||||||
- Definition Amount of noncash expense for share-based payment arrangement. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
  | 
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available. 
  | 
| X | ||||||||||
- Details 
  | 
| X | ||||||||||
- Details 
  | 
| X | ||||||||||
- Details 
  |