|
Weighted Average Assumptions For Options Granted (Detail)
|
3 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
|
Mar. 31, 2013
|
Mar. 31, 2012
|
Dec. 31, 2012
|
Dec. 31, 2011
|
|
| Stock-Based Compensation | ||||
| Expected term (in years) | 4 years | 4 years | 4 years | 4 years |
| Expected volatility | 84.90% | 118.17% | 117.20% | 90.90% |
| Risk free rate | 0.56% | 0.62% | 0.61% | 1.27% |
| Expected dividends | 0.00% | 0.00% | 0.00% | 0.00% |
| X | ||||||||||
|
- Details
|
| X | ||||||||||
|
- Definition
The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
|
- 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
|
| X | ||||||||||
|
- 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
|
| X | ||||||||||
|
- 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
|