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Stock Options and Other Compensation - Additional Information (Detail)
Mar. 31, 2021
$ / shares
shares
May 31, 2020
$ / shares
shares
May 31, 1989
Officers
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Options outstanding, shares | shares 767,500 767,500  
Number of key executive officers to whom non-statutory stock options granted | Officers     4
Minimum [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Average exercise price | $ / shares $ 1.00 $ 1.00  
Maximum [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Average exercise price | $ / shares $ 1.25 $ 1.25  
Nonstatutory Stock Options [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Options exercisable, shares | shares 767,500 767,500