Stockholder's Equity - Additional Information (Detail) - USD ($)				3 Months Ended			6 Months Ended
	Jun. 02, 2015	Mar. 20, 2015	Feb. 04, 2015	Jun. 30, 2015	Mar. 31, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Class of Stock [Line Items]
Preferred stock, par value				$ 0.0001			$ 0.0001		$ 0.0001
Preferred stock, shares authorized				10,000,000			10,000,000		10,000,000
Common stock, par value				$ 0.0001			$ 0.0001		$ 0.0001
Common stock, shares authorized				100,000,000			100,000,000		100,000,000
Fair value of Series A and Series A-1 Preferred Stock dividends				$ 24,000		$ 1,213,000	$ 209,000	$ 2,968,000
Number of common stock issued upon conversion of convertible instrument				35,000
Research and development expenses							$ 228,000
Common stock, shares issued				64,949,121			64,949,121		21,984,272
Net proceeds from the issuance of common stock	$ 9,200,000						$ 9,254,000	$ 1,947,000
Units issued, shares	26,000,000
Sale of units, price per unit	$ 0.40
Description of transaction	Each unit consists of one share of common stock, a 13-month overallotment purchase right to purchase one-half of one share of common stock at a price of $0.455 per full share of common stock (the "Overallotment Purchase Rights") and a five-year warrant to purchase one-half of one share of common stock at a price of $0.52 per full share of common stock (the "Warrants").
Gross proceeds from public offering	$ 10,400,000
Gross proceeds from warrants exercised				$ 16,000			$ 16,000
Warrants to Purchase Common Stock [Member]
Class of Stock [Line Items]
Sale of stock, price per share	$ 0.52
Overallotment Purchase Rights [Member]
Class of Stock [Line Items]
Sale of stock, price per share	$ 0.455
Hapten Pharmaceuticals, LLC [Member]
Class of Stock [Line Items]
License fee			$ 100,000		$ 100,000
Research and development expenses					$ 228,000
Hapten Pharmaceuticals, LLC [Member] | Common Stock [Member]
Class of Stock [Line Items]
Common stock, shares issued			200,000
Tang Capital Partners, L.P. ("TCP") [Member]
Class of Stock [Line Items]
Dividend payment terms							On May 22, 2015, the Company entered into an agreement with Tang Capital Partners, L.P. ("TCP") pursuant to which the Company and TCP agreed to accelerate the dividend payment date to no later than May 29, 2015 and upon issuance immediately convert the dividend shares into common stock. For the three months ended June 30, 2015, the dividend payment date was accelerated to May 27, 2015.
Lincoln Park Capital Fund, LLC [Member] | Common Stock [Member]
Class of Stock [Line Items]
Common stock, shares issued				50,000			50,000
Net proceeds from the issuance of common stock				$ 0			$ 64,000
Series A-1 Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, par value				$ 0.0001			$ 0.0001		$ 0.0001
Preferred stock, shares authorized				10,000			10,000		10,000
Series A-1 Preferred Stock, shares outstanding				0			0		1,578
Preferred stock, annual dividend rate							7.00%
Preferred stock, face amount				$ 1,000			$ 1,000
Dividends issued on Preferred Stock						80	21	152
Fair value of Series A and Series A-1 Preferred Stock dividends						$ 588,000	$ 37,000	$ 1,333,000
Percentage of affiliates owning shares							9.999%
Preferred stock, conversion rate				2,437.57			2,437.57
Conversion of preferred stock into common shares				21		353	3,599	859
Shares of Series A Preferred Stock exchanged for Series A-1 Preferred Stock		2,000
Series A-1 Convertible Preferred Stock [Member] | Common Stock [Member]
Class of Stock [Line Items]
Number of common stock issued upon conversion of convertible instrument				51,759		860,457	8,772,903	2,093,859
Series A Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, annual dividend rate							7.00%
Preferred stock, face amount				$ 1,000			$ 1,000
Dividends issued on Preferred Stock				21		85	105	181
Percentage of affiliates owning shares							9.999%
Preferred stock, conversion rate				2,437.57			2,437.57
Conversion of preferred stock into common shares				3,106		0	3,215	166
Shares of Series A Preferred Stock exchanged for Series A-1 Preferred Stock		2,000
Series A Convertible Preferred Stock [Member] | Common Stock [Member]
Class of Stock [Line Items]
Number of common stock issued upon conversion of convertible instrument				7,571,218			7,837,400	405,720