Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Antidilutive Securities (Detail)

v3.21.4
Summary of Significant Accounting Policies - Antidilutive Securities (Detail) - shares
shares in Thousands
6 Months Ended
Nov. 30, 2021
Nov. 30, 2020
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 73,223 82,796
Convertible Debt Securities    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount 12,000 12,000
Convertible Preferred Stock    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount 34,089 31,490