Stockholders' Equity - Additional Information (Detail) - USD ($)						12 Months Ended
	Jun. 02, 2015	May. 27, 2015	Feb. 04, 2015	Dec. 18, 2014	Apr. 22, 2014	Dec. 31, 2015	Dec. 31, 2014	Nov. 06, 2015
Class of Stock [Line Items]
Preferred stock, par value						$ 0.0001	$ 0.0001
Preferred stock, shares authorized						10,000,000	10,000,000
Common stock, par value						$ 0.0001	$ 0.0001
Common stock, shares authorized						100,000,000	100,000,000
Fair value of Series A and Series A-1 convertible preferred stock dividends						$ 209,000	$ 4,130,000
Number of common stock issued upon conversion of convertible instrument						435,000
Fair value of common stock issued in exchange for patent and technology rights						$ 228,000
Sale of units, price per unit	$ 0.40
Units issued, shares	26,000,000
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
Net proceeds from the issuance of common stock	$ 9,200,000					9,266,000	$ 1,886,000
Gross proceeds from warrants exercised						$ 198,000
Series A-1 Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Series A-1 Preferred Stock, shares outstanding						0	1,578
Dividends issued on Preferred Stock		0				21	240
Fair value of Series A and Series A-1 convertible preferred stock dividends						$ 37,000	$ 1,731,000
Conversion of preferred stock into common shares		0				3,599	3,716
Preferred stock, accelerated dividend payment date						May 27, 2015
Number of common stock issued upon conversion of convertible instrument						(3,599)	(3,716)
Preferred Stock, shares eliminated								10,000
Series A-1 Preferred Stock, shares authorized						0	10,000
Series A-1 Preferred Stock, shares issued						0	1,578
Lincoln Park Capital Fund, LLC [Member]
Class of Stock [Line Items]
Common stock, shares issued							500,000
Stock reserved during period, value				$ 10,800,000	$ 20,000,000
Stock issued as a commitment fee, shares				100,000			100,000
Sale of units, price per unit				$ 1.93			$ 4.00
Tang Capital Partners, L.P. ("TCP") [Member]
Class of Stock [Line Items]
Series A-1 Preferred Stock, shares outstanding						0
Dividend payment terms						On May 22, 2015, the Company entered into an agreement (the “Acceleration and Conversion Agreement”) with Tang Capital Partners, L.P. (“TCP”) pursuant to which the Company and TCP agreed to accelerate the next dividend payment date from June 30, 2015 to no later than May 29, 2015, and upon payment of such dividend immediately convert the dividend shares into common stock. In connection therewith, the dividend payment date was accelerated to May 27, 2015. There were no shares of Series A convertible preferred stock (“Series A Preferred Stock”) outstanding after the completion of the Acceleration and Conversion Agreement.
Hapten Pharmaceuticals, LLC [Member]
Class of Stock [Line Items]
License fee			$ 100,000			$ 100,000
Fair value of common stock issued in exchange for patent and technology rights						$ 228,000
Common Stock [Member]
Class of Stock [Line Items]
Number of common stock issued upon conversion of convertible instrument						16,610,303	9,463,712
Common stock, shares issued						50,000	700,000
Common Stock [Member] | Series A-1 Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Number of common stock issued upon conversion of convertible instrument						8,772,903	9,057,992
Common Stock [Member] | Lincoln Park Capital Fund, LLC [Member]
Class of Stock [Line Items]
Common stock, shares issued						50,000
Net proceeds from the issuance of common stock						$ 64,000	$ 1,900,000
Common Stock [Member] | Hapten Pharmaceuticals, LLC [Member]
Class of Stock [Line Items]
Common stock, shares issued			200,000
Overallotment Purchase Rights [Member]
Class of Stock [Line Items]
Sale of stock, price per share	$ 0.455
Warrants to Purchase Common Stock [Member]
Class of Stock [Line Items]
Sale of stock, price per share	$ 0.52