Summary of Significant Accounting Policies - Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share (Detail) - shares shares in Thousands |
6 Months Ended | |
|---|---|---|
Nov. 30, 2020 |
Nov. 30, 2019 |
|
| Stock options, warrants & unvested restricted stock | ||
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||
| Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | 82,796 | 177,457 |
| Convertible Debt Securities [Member] | ||
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||
| Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | 12,000 | 10,048 |
| Convertible Preferred Stock [Member] | ||
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||
| Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | 31,490 | 17,550 |