Derivative Financial Instruments - Components of (Expense) Income of Derivative Financial Instruments (Detail) - USD ($) $ in Thousands |
12 Months Ended | |
|---|---|---|
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Derivative Instruments, Gain (Loss) [Line Items] | ||
| Derivative (loss) gain | $ (13,167) | $ 121 |
| Free Standing Warrants Assets, Related Party [Member] | ||
| Derivative Instruments, Gain (Loss) [Line Items] | ||
| Derivative (loss) gain | $ (51) | |
| Shares into which derivative liability can be settled | 1,999,436 | |
| Free Standing Warrants Liabilities [Member] | ||
| Derivative Instruments, Gain (Loss) [Line Items] | ||
| Derivative (loss) gain | $ (13,167) | $ 172 |