Stockholders' Equity - Additional Information 2 (Detail) - USD ($)	1 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended
	Nov. 30, 2014	Nov. 30, 2013	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Mar. 31, 2012	Mar. 31, 2011
Class Of Stock [Line Items]
Warrant liability reduced					$ 138,000	$ 55,000
Exercised derivative liabilities			0	0	38,234	8,647
Warrants to purchase common stock	145,000	75,000
Warrants maturity term	5 years	5 years					5 years	5 years
Volatility	76.78%	96.90%	74.26%	76.30%	74.25%	77.10%
Risk-free interest rate	1.37%	0.60%	1.48%	1.66%	1.60%	1.61%
Recognized expenses of warrants			$ 101,000		$ 202,000
Warrants earned, service period	17 months	12 months
Warrants issued						50,000
Weighted-average remaining contractual term of options exercisable					7 years 2 months 9 days
Preferred stock, shares authorized			25,000,000		25,000,000
Preferred stock, shares outstanding			0		0
Consultation Service Agreement September 2014
Class Of Stock [Line Items]
Recognized expenses of warrants					$ 273,000
Consultation Service Agreement November 2014
Class Of Stock [Line Items]
Recognized expenses of warrants			$ 9,000		$ 25,000
Minimum [Member]
Class Of Stock [Line Items]
Warrants exercisable price, per share			$ 0.85		$ 0.85
Maximum [Member]
Class Of Stock [Line Items]
Warrants exercisable price, per share			$ 7.62		$ 7.62
Warrants [Member]
Class Of Stock [Line Items]
Number of warrant exercised through cashless			0	0	38,234	8,647
Cashless exercise for issuance of common stock					30,186	7,600
Number Of Warrants Exercised				0		103,000
Warrants exercisable price, per share	$ 6.84	$ 7.36
Warrant liability reduced				$ 0		$ 224,000
Amount reversed against operating expense					$ 130,000
Warrants liability					$ 138,000	$ 55,000
Estimated fair value of warrants	$ 309,000	$ 404,000
Weighted-average remaining contractual term of options exercisable					1 year 10 months 21 days
Warrants [Member] | Minimum [Member]
Class Of Stock [Line Items]
Warrants exercisable price, per share				$ 1.00		$ 1.00
Warrants [Member] | Maximum [Member]
Class Of Stock [Line Items]
Warrants exercisable price, per share				$ 2.21		$ 2.21