Debt and Warrants - Summary of Shares of Common Stock Warrants Outstanding (Detail)	9 Months Ended
	Sep. 30, 2015 $ / shares shares
Class Of Warrant Or Right [Line Items]
Shares Outstanding	64,657
November 2018 [Member]
Class Of Warrant Or Right [Line Items]
Issuance Date	2011-11
Expiration Date	2018-11
Per Share Exercise Price | $ / shares	$ 10.14
Shares Outstanding	11,835
May 2023 [Member]
Class Of Warrant Or Right [Line Items]
Issuance Date	2013-05
Expiration Date	2023-05
Per Share Exercise Price | $ / shares	$ 108.18
Shares Outstanding	1,039
June 2021 [Member]
Class Of Warrant Or Right [Line Items]
Issuance Date	2014-06
Expiration Date	2021-06
Per Share Exercise Price | $ / shares	$ 10.14
Shares Outstanding	51,783