Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Going concern thru intangibles (Detail)

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Summary of Significant Accounting Policies - Going concern thru intangibles (Detail) - USD ($)
 3 Months Ended 6 Months Ended 9 Months Ended 12 Months Ended
Nov. 30, 2021
Aug. 31, 2021
Feb. 28, 2021
Nov. 30, 2020
Aug. 31, 2020
Nov. 30, 2021
Nov. 30, 2020
Feb. 28, 2021
May 31, 2021
May 31, 2020
May 31, 2019
Accounting Policies [Abstract]                      
Net loss $ 36,604,000 $ 31,458,000 $ 45,206,000 $ 35,425,000 $ 30,832,000 $ 68,062,000 $ 66,257,000 $ 111,463,000 $ 157,230,000 $ 139,936,000 $ 60,719,000
Accumulated deficit 603,353,000 $ 566,318,000       603,353,000     534,440,000 $ 375,301,000 $ 234,420,000
Balance in excess of federally insured limits 8,600,000         8,600,000     $ 33,700,000    
Intangible asset impairment charges $ 0     $ 0   $ 0 $ 0