Annual report pursuant to Section 13 and 15(d)

Description of Stock Plans - Calculating Fair Value Options Granted Using the Black-Scholes Option- Pricing Model (Detail)

v3.21.1
Description of Stock Plans - Calculating Fair Value Options Granted Using the Black-Scholes Option- Pricing Model (Detail)
 12 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Mar. 31, 2019
Minimum      
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]      
Expected life of the options 4 years 11 months 4 days 5 years 7 days 5 years 6 months 7 days
Maximum      
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]      
Expected life of the options 5 years 2 months 23 days 9 years 9 months 29 days 9 years 2 months 8 days
Risk-free interest rate | Minimum      
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]      
Stock options, measurement input 0.21% 0.64% 2.38%
Risk-free interest rate | Maximum      
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]      
Stock options, measurement input 0.66% 2.25% 2.96%
Expected volatility      
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]      
Stock options, measurement input     66.00%
Expected volatility | Minimum      
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]      
Stock options, measurement input 64.00% 64.00%  
Expected volatility | Maximum      
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]      
Stock options, measurement input 72.00% 66.00%  
Expected dividend yield      
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]      
Stock options, measurement input 0.00% 0.00% 0.00%
Expected forfeitures      
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]      
Stock options, measurement input   29.00% 29.00%
Expected forfeitures | Minimum      
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]      
Stock options, measurement input 6.00%    
Expected forfeitures | Maximum      
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]      
Stock options, measurement input 7.00%