Schedule of Estimated Fair Value Assumption of Term Loan and 2017 Notes (Detail) (USD $)	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Stock price	$ 0.86	$ 1.43
Conversion Rate	175.6697	175.6697
Conversion Price	$ 5.69	$ 5.69
Maturity date	Jul. 01, 2022	Jul. 01, 2022
Risk-free interest rate	2.30%	2.80%
Estimated stock volatility	80.00%	65.00%
Estimated credit spread	26.00%	33.00%
Convertible 2017 Notes
Debt Instrument [Line Items]
Conversion Rate	0.8663
Convertible 2017 Notes | Term Loans
Debt Instrument [Line Items]
Stock price	$ 0.86
Conversion Rate	863.3
Conversion Price	$ 1.16
Maturity date	Mar. 15, 2017
Risk-free interest rate	0.76%
Estimated stock volatility	80.00%
Estimated credit spread	20.00%