Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - FV (Detail)

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Summary of Significant Accounting Policies - FV (Detail) - USD ($)
$ in Thousands
 9 Months Ended 12 Months Ended
Feb. 28, 2021
May 31, 2020
May 31, 2019
May 31, 2018
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Beginning Balance   $ 2,407 $ 1,324  
Ending Balance     2,407 $ 1,324
Forfeiture rate 0.00%      
Redemption Provision Embedded Derivative        
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Warrants issued     2,750  
Fair value adjustments   (2,005) (745)  
Warrant Derivative Liability        
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Warrants issued       4,360
Fair value adjustments   11,547 $ (922) (3,855)
Exercises   $ (11,949)    
Over-Allotment Option [Member] | Warrant Derivative Liability        
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Warrants issued       $ 819