Derivative Instruments - Additional Information (Detail) (USD $)	12 Months Ended					9 Months Ended	12 Months Ended										0 Months Ended		12 Months Ended
	Dec. 31, 2013 Amended and Restated Convertible Notes [Member]	Dec. 31, 2012 Amended and Restated Convertible Notes [Member]	Dec. 31, 2011 Amended and Restated Convertible Notes [Member]	Dec. 31, 2013 Amended and Restated Reimbursement Notes [Member]	Dec. 31, 2013 Amended and Restated Bridge Notes [Member]	Dec. 31, 2013 Amended and Restated June 2010 Warrants [Member]	Dec. 31, 2013 Amended and Restated June 2010 Warrants [Member]	Dec. 31, 2012 Amended and Restated June 2010 Warrants [Member]	Dec. 31, 2011 Amended and Restated June 2010 Warrants [Member]	Dec. 31, 2013 Warrant [Member]	Dec. 31, 2013 Amended and Restated August 2009 Warrants [Member]	Dec. 31, 2012 Amended and Restated August 2009 Warrants [Member]	Dec. 31, 2011 Amended and Restated August 2009 Warrants [Member]	Dec. 31, 2013 Amended and Restated August 2010 Warrants [Member]	Dec. 31, 2012 Amended and Restated August 2010 Warrants [Member]	Dec. 31, 2011 Amended and Restated August 2010 Warrants [Member]	Jan. 12, 2011 August 2010 Investor Warrants [Member]	Jan. 02, 2011 August 2010 Investor Warrants [Member]	Dec. 31, 2013 August 2010 Investor Warrants [Member]	Dec. 31, 2012 August 2010 Investor Warrants [Member]	Dec. 31, 2011 August 2010 Investor Warrants [Member]	Dec. 31, 2013 Amended and Restated August 2010 MHR Waiver Warrants [Member]	Dec. 31, 2012 Amended and Restated August 2010 MHR Waiver Warrants [Member]	Dec. 31, 2011 Amended and Restated August 2010 MHR Waiver Warrants [Member]	Dec. 31, 2013 Amended and Restated July 2011 Warrants [Member]	Dec. 31, 2012 Amended and Restated July 2011 Warrants [Member]	Dec. 31, 2011 Amended and Restated July 2011 Warrants [Member]	Dec. 31, 2013 July 2011 Warrants [Member]	Dec. 31, 2012 July 2011 Warrants [Member]	Dec. 31, 2013 Amended and Restated July 2011 MHR Waiver Warrants [Member]	Dec. 31, 2012 Amended and Restated July 2011 MHR Waiver Warrants [Member]	Dec. 31, 2013 2013 Restructuring Warrants [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Issuance of common stock	$ 10,000,000					$ 10,000,000	$ 10,000,000
Fair value assumption stock price	$ 0.18			$ 0.18	$ 0.18	$ 0.18	$ 0.18			$ 0.18							$ 2.25			$ 0.18								$ 0.18				$ 0.18
Fair value assumption conversion price	$ 1.25			$ 0.50	$ 0.50
Expected volatility rate	160.00%			99.00%	160.00%		150.00%			153.34%							107.30%			165.11%								182.79%				153.34%
Remaining term of expected volatility	3 years 9 months			4 months	3 years 9 months		5 years 6 months			5 years 6 months							4 years 7 months			1 year 8 months								2 years 6 months				5 years 6 months
Risk-free interest rate	1.13%			0.07%	1.13%		1.90%			1.75%							1.99%			0.38%								0.63%				1.75%
Fair value of embedded conversion feature increased/(decreased)	10,100,000	7,100,000	3,800,000	100,000	100,000		200,000	300,000	1,100,000		200,000	200,000	7,300,000	100,000	100,000	4,900,000
Number of warrants issued						865,000	865,000												2,600,000									3,010,000
Reduced exercise price of warrants						$ 0.50	$ 0.50																									$ 0.50
Warrants expiry date						Jul. 08, 2019	Jul. 08, 2019																					Jul. 06, 2016
Assumption exercise price							$ 0.50			$ 0.50																		$ 1.09
Number of warrants sold to MHR											3,700,000			2,600,000								975,000			3,010,000					795,000		10,000,000
Fair value of warrants decreased																	28,000	200,000	100,000	100,000	4,500,000	100,000	400,000	1,800,000		10,000	1,800,000		30,000	33,000	500,000	500,000
Proceeds from warrants exercised																	200,000
Number of warrants exercised by unrelated investors																	200,000
Exercise price of the warrants issued																			$ 1.26									$ 1.09
Fair value of warrants increased																									$ 100,000			$ 28,000		$ 37,000