Difference between (Benefit) Expense from Income Taxes and Amount Computed by Applying Statutory Income Tax Rate to Income Before Taxes (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Taxes [Line Items]
Benefits from taxes at statutory rate	$ (42,355)	$ (42,517)	$ (16,652)
Rate differential	18,494	13,249	3,952
Change in valuation reserves	33,106	22,515	7,120
Permanent & other	(985)	6,809	2,209
Warrant derivative liabilities	(11,984)	8,904	5,643
Other	530	156	244
Benefit from (provision for) income taxes	$ (3,194)	$ 9,116	$ 2,516