Derivative Instruments - Additional Information (Detail) - USD ($)	8 Months Ended		12 Months Ended
	Aug. 26, 2015	Dec. 31, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Jan. 12, 2011
Convertible Notes [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
Fair value of embedded conversion feature increased/(decreased)			5,700,000	$ 8,900,000	$ 10,100,000
Reimbursement Notes [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Fair value of embedded conversion feature increased/(decreased)		$ (100,000)	300,000	700,000
Bridge Notes [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Fair value of embedded conversion feature increased/(decreased)		(100,000)	800,000	700,000
Amended and Restated June 2010 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
Fair value of embedded conversion feature increased/(decreased)			$ 300,000	32,000	200,000
Number of warrants issued			865,000
Reduced exercise price of warrants			$ 0.50
Warrants expiry date			Jul. 08, 2019
Warrants [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Fair value of embedded conversion feature increased/(decreased)			$ 3,800,000	1,000,000	600,000
August 2010 Investor Warrants [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Number of warrants issued			2,600,000
Warrants expiry date			Aug. 26, 2015
Number of warrants exercised by unrelated investors						200,000
Fair value of warrants decreased	$ 29,000			100,000	100,000
July 2011 Investor Warrants [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Warrants expiry date			Jul. 06, 2016
Fair value of warrants decreased			$ 5,000	200,000
Number of warrants sold to MHR			3,010,000
Exercise price of warrants issued			$ 1.09
Fair value of warrants increased					$ 28,000
2013 Restructuring Warrants [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Fair value of warrants decreased		$ 500,000
Fair value of warrants increased			$ 3,300,000	$ 900,000
Number of warrants sold to MHR			10,000,000