Warrants to Purchase Series 1 Nonconvertible Preferred Stock and Series 1 Nonconvertible Preferred Stock - Additional Information (Detail) - Series 1 Nonconvertible Preferred Stock [Member] - shares	6 Months Ended
	Mar. 31, 2017	Nov. 30, 2010
Class of Warrant or Right [Line Items]
Number of shares issuable upon exercise of the warrants		1,999,989
Warrant expiration date	Oct. 04, 2017