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)

v3.8.0.1
Description of Stock Plans - Calculating Fair Value Options Granted Using the Black-Scholes Option- Pricing Model (Detail)
12 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Mar. 31, 2016
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]      
Expected dividend yield 0.00% 0.00% 0.00%
Minimum      
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]      
Risk-free interest rate 1.77% 1.34% 1.37%
Expected life of the options 5 years 7 months 24 days 5 years 8 months 9 days 5 years 8 months 23 days
Stock price volatility 66.00% 73.00% 78.00%
Expected forfeitures 28.00% 10.00% 10.00%
Maximum      
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]      
Risk-free interest rate 2.73% 2.38% 2.27%
Expected life of the options 9 years 10 months 2 days 9 years 10 months 2 days 10 years
Stock price volatility 73.00% 130.00% 145.00%
Expected forfeitures 29.00% 35.00% 35.00%