Share-Based Compensation - Summary of Assumptions Used to Value Stock Options on Date of Grant (Detail) - USD ($) None in scaling factor is -9223372036854775296 |
12 Months Ended | |
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Dec. 31, 2013 |
Dec. 31, 2012 |
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| Employee Stock Option [Member] | ||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
| Expected dividend yield | ||
| Expected volatility | 73.39% | 77.00% |
| Risk-free interest rate | 0.92% | 0.49% |
| Expected life of option (years) | 4 years | 3 years 3 months |
| Weighted-average share price | $ 0.29 | $ 0.37 |
| Weighted-average exercise price | $ 1.22 | $ 0.91 |
| Model used | Black-Scholes | Black-Scholes |
| Joint Share Ownership Plan Awards [Member] | ||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
| Expected volatility | 76.00% | |
| Risk-free interest rate | 0.57% | |
| Expected life of option (years) | 3 years | |
| Weighted-average share price | $ 0.17 | |
| Weighted-average exercise price | $ 0.17 | |
| Model used | Monte Carlo | |
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- Definition The estimated amount of dividends to be paid to holders of the underlying shares (expected dividends) over the option's term. Dividends are taken into account because payment of dividends to shareholders reduces the fair value of the underlying shares, and option holders generally do not receive dividends. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition For each plan, identification of the award pricing model or other valuation method used in calculating the weighted average fair values disclosed. The model is also used to calculate the compensation expense that is shown within the balance sheet, income statement, and cash flow. Examples of valuation techniques are lattice models (binomial model), closed-form models (Black-Scholes-Merton formula), and a Monte Carlo simulation technique. Fair value is the amount at which an asset or liability could be bought or incurred or sold or settled in a current transaction between willing parties, that is, other than in a forced or liquidation sale. May include disclosures about the assumptions underlying application of the method selected. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The risk-free interest rate assumption that is used in valuing an option on its own shares. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition The weighted average of per share prices paid for shares purchased on the open market for issuance to employees under the plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options. No definition available.
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- Definition Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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