Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Antidilutive Securities (Detail)

v3.21.2
Summary of Significant Accounting Policies - Antidilutive Securities (Detail) - shares
shares in Thousands
 12 Months Ended
May 31, 2021
May 31, 2020
May 31, 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 82,386 131,361 178,592
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 18,000 3,864 11,346
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 33,008 30,130 7,974