Fair Value Measurements - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended				6 Months Ended
	Dec. 31, 2013	Jun. 30, 2014	Dec. 31, 2013 Fair Value, Inputs, Level 1	Jun. 30, 2014 Fair Value, Inputs, Level 2	Jun. 30, 2014 Secured Debt	Jun. 30, 2014 Senior Notes	Jun. 30, 2014 Convertible Debt	Dec. 31, 2013 Convertible Debt
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Estimated fair value					$ 1.0	$ 31.2	$ 17.2	$ 15.9
Amortization period of debt discount					36 months
Debt Instrument Maturity Date					2017-05
Debt instrument, interest rate, effective percentage	11.00%				9.00%
Estimated fair value of the embedded derivatives	3.5	0.7
Common stock shares issued and sold	21,303,750
Derivative warrant liability fair value	$ 7.2	$ 4.7	$ 7.2	$ 4.7