Weighted Average Assumptions Used to Calculate Fair Value of Options Granted (Detail)	3 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Risk-free interest rate	1.57%	0.85%
Expected option life (years)	4 years 2 months 9 days	4 years 3 months 4 days
Expected volatility	49.40%	51.90%