Stock-Based Compensation - Assumptions to Estimate Fair Value of Option Grants (Parenthetical) (Detail) (USD $)	6 Months Ended	12 Months Ended
	Sep. 30, 2014	Mar. 31, 2014
Black Scholes Based Option Pricing Model | 2015 $4.61 Value Per Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average value per option granted	$ 4.61
Black Scholes Based Option Pricing Model | 2015 $3.85 Value Per Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average value per option granted	$ 3.85
Black Scholes Based Option Pricing Model | 2014 $3.03 Value Per Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average value per option granted	$ 3.03	$ 3.03
Black Scholes Based Option Pricing Model | 2014 $3.01 Value Per Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average value per option granted	$ 3.01	$ 3.01
Monte Carlo Simulation | 2015 $3.05 Value Per Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average value per option granted	$ 3.05
Monte Carlo Simulation | 2015 $2.14 Value Per Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average value per option granted	$ 2.49
Monte Carlo Simulation | 2014 $1.90 Value Per Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average value per option granted	$ 1.90	$ 1.90
Monte Carlo Simulation | 2014 $1.71 Value Per Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average value per option granted	$ 1.71	$ 1.71