Stockholders' Equity - Additional Information (Detail) (USD $)	0 Months Ended
	Feb. 24, 2014	Oct. 11, 2013	Mar. 31, 2015	Sep. 30, 2014
Class Of Stock [Line Items]
Capital stock authorized for issuance			150,000,000
Common stock, shares authorized			145,000,000	145,000,000
Common stock, par value			$ 0.001	$ 0.001
Preferred stock, shares authorized			5,000,000	5,000,000
Preferred stock, par value			$ 0.001	$ 0.001
Common stock, shares outstanding			59,435,862	54,656,936
Preferred stock, shares outstanding			15,652	18,300
Threshold percentage of common stock ownership upon preferred stock conversion			9.99%
Stock issuances, Shares	6,325,000	3,071,672
Sale of stock, price per share	$ 18.95	$ 5.86
Conversion price		$ 5.86
Proceeds from issuance of common stock, net	$ 112,600,000	$ 60,000,000
Series C Preferred Stock
Class Of Stock [Line Items]
Common stock equivalent of preferred stock			2,670,990
Preferred stock, shares outstanding			15,652
Stock issuances, Shares		46,000
Sale of stock, price per share		$ 1,000
Aggregate price on issuance or Sale of equity		$ 64,000,000
2004 Equity Incentive Plan, 2013 Equity Incentive Plan, and Inducement Grants
Class Of Stock [Line Items]
Common Stock, Share reserve for issuance			8,192,654