Derivative Liability - Assumptions Used to Value Derivative Liabilities at Closing Dates of Private Placements (Detail) (Warrant Derivative Liability [Member], USD $)	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Warrant Derivative Liability [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Closing price per share of common stock	$ 3.54	$ 7.64
Exercise price per share	$ 1.00	$ 1.00
Expected volatility	76.80%	76.50%
Risk-free interest rate	0.56%	0.90%
Dividend yield	0.00%	0.00%
Remaining expected term of underlying securities (years)	1 year 11 months 16 days	2 years 11 months 16 days