Weighted Average Assumptions Used to Calculate Fair Value of Options Granted (Detail)	3 Months Ended		9 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
Share based Compensation Arrangement by Share based Payment Award, Fair Value Assumptions, Method Used [Line Items]
Risk-free interest rate	1.71%	0.63%	0.94%	0.77%
Expected option life (years)	4 years 2 months 5 days	4 years 2 months 23 days	4 years 3 months	4 years 3 months 26 days
Expected volatility	50.20%	58.10%	51.80%	56.40%