Stockholders' Equity - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended		1 Months Ended	0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Jul. 24, 2014	Feb. 05, 2014	Oct. 29, 2013	Jul. 21, 2014	Oct. 31, 2013
Securities Financing Transaction [Line Items]
Preferred Stock, Shares Authorized	10,000,000	10,000,000
Preferred Stock, Par or Stated Value Per Share	$ 0.10	$ 0.10
Preferred Stock, Shares Issued	11,787	0
Preferred Stock, Shares Outstanding	11,787	0
Convertible Preferred Stock Initial Conversion Price						$ 2.565
Preferred Stock, Value, Issued	$ 1	$ 0
Stock Issued During Period, Value, Conversion of Convertible Securities	0
Convertible Preferred Stock Converted to Other Securities	1,887
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	233	3,017
Fair Value Adjustment of Warrants	2,784	206
Registration Rights Liquidating Damages	3,420	0
Common Stock, Shares Authorized	50,000,000	50,000,000
Common Stock, Par or Stated Value Per Share	$ 0.001	$ 0.001
Common Stock, Shares, Issued	6,037,232	4,750,160
Common Stock, Shares, Outstanding	6,037,232	4,750,160
Aggregate Consideration Receivable For Warrants To Be Issued							685,715
Series B [Member]
Securities Financing Transaction [Line Items]
Stock Issued During Period, Value, Conversion of Convertible Securities	2,487
Series B Prefunded Warrants [Member]
Securities Financing Transaction [Line Items]
Warrants Issued to Purchase Common Stock, Shares			4,795,321
Class of Warrant or Right, Exercise Price of Warrants or Rights			2.45
Aggregate Consideration Receivable For Warrants To Be Issued					434,325
Convertible Preferred Stock [Member]
Securities Financing Transaction [Line Items]
Stock Issued During Period, Shares, New Issues			12,300,000
Convertible Preferred Stock [Member] | Series B [Member]
Securities Financing Transaction [Line Items]
Stock Issued During Period, Shares, New Issues			12,300
Preferred Stock Stated Value Per Share			1,000.00
Convertible Preferred Stock Initial Conversion Price			2.565
Series B Preferred Stock [Member]
Securities Financing Transaction [Line Items]
Preferred Stock, Par or Stated Value Per Share				$ 1,000.00
Stock Issued During Period, Shares, New Issues	12,300,000	0
Preferred Stock Stated Value Per Share				$ 0.10
Convertible Preferred Stock, Shares Issued upon Conversion			4,795,321
Stock Issued During Period, Value, Conversion of Convertible Securities	0
Common Stock Equivalents of Convertible Preferred Stock [Member]
Securities Financing Transaction [Line Items]
Preferred Stock, Par or Stated Value Per Share				$ 1,000.00
Preferred Stock, Shares Issued				12,300
Preferred Stock Stated Value Per Share				$ 0.10
Convertible Preferred Stock Initial Conversion Price				$ 8.40
Warrants Issued to Purchase Common Stock, Shares				1,329,731
Class of Warrant or Right, Exercise Price of Warrants or Rights				$ 7.40
Convertible Preferred Stock, Shares Issued upon Conversion				1,464,287
Proceeds from Issuance of Warrants				11,458
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	266
Fair Value Adjustment of Warrants	5,319
Series B Warrants [Member]
Securities Financing Transaction [Line Items]
Warrants Issued to Purchase Common Stock, Shares			4,795,321
Class of Warrant or Right, Exercise Price of Warrants or Rights			2.45
Preferred Stock, Value, Issued	12,300
Series A Warrants [Member]
Securities Financing Transaction [Line Items]
Warrants Issued to Purchase Common Stock, Shares						6,198,832
Class of Warrant or Right, Exercise Price of Warrants or Rights					$ 8.50	$ 2.45
Proceeds From Borrowings And Warrant Exercises					$ 6,000
Common Stock, Par or Stated Value Per Share						$ 0.001
Common Stock, Shares, Issued					422,819
Aggregate Consideration Receivable For Warrants To Be Issued					685,715