Nature of Operations, Risks and Uncertainties and Liquidity - Additional Information (Detail) (USD $)	0 Months Ended	3 Months Ended								12 Months Ended								0 Months Ended
	May 06, 2013	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Apr. 26, 2013	Oct. 17, 2012	Sep. 27, 2012	Dec. 31, 2010	Dec. 31, 2013 Amended and Restated [Member]	Jan. 21, 2014 Subsequent Event [Member]	Apr. 26, 2013 MHR Promissory Notes [Member]	Sep. 27, 2012 MHR Promissory Notes [Member]	Sep. 26, 2012 MHR Promissory Notes [Member]	Sep. 26, 2005 MHR Promissory Notes [Member]
Debt Instrument [Line Items]
Working capital deficiency		$ 1,400,000								$ 1,400,000
Cash and cash equivalents		4,053,000				1,484,000				4,053,000	1,484,000	3,069,000				5,326,000
Stockholders' deficit		(86,801,000)				(66,066,000)				(86,801,000)	(66,066,000)	(64,527,000)				(82,520,000)
Accumulated deficit		(488,759,000)				(467,820,000)				(488,759,000)	(467,820,000)
Net income (loss)		(2,813,000)	(1,720,000)	(13,982,000)	(2,424,000)	627,000	(4,587,000)	2,768,000	(736,000)	(20,939,000)	(1,928,000)	15,051,000
Operating loss		(2,343,000)	(1,761,000)	(1,788,000)	(1,712,000)	(2,161,000)	(1,474,000)	(1,421,000)	(1,765,000)	(7,604,000)	(6,821,000)	(8,136,000)
Non-interest bearing promissory notes		556,000				600,000				556,000	600,000									600,000
Promissory Note issued to MHR, principal amount														1,400,000
Interest rate of loan															13.00%					11.00%	10.00%	11.00%
Senior Secured Convertible Notes, effective date										Sep. 27, 2012
Company's obligations under Convertible Notes		35,935,000				31,576,000				35,935,000	31,576,000						35,900,000		32,900,000
Company's obligations under Reimbursement Notes		637,000				600,000				637,000	600,000						600,000		600,000
Company's obligations under Bridge Notes		1,627,000				1,431,000				1,627,000	1,431,000						1,600,000		1,500,000
Prepayment of certain development milestone payments													10,000,000
Payment received from Novo Nordisk as deferred revenue	10,000,000
Process from participation in program																		$ 1,700,000