|
Stockholders' Equity (Deficiency) (Summary of Compensation Expense for Stock Options Granted to Employees) (Details) (Stock Incentive Plan To Employees And Directors [Member])
|
3 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
|
Mar. 31, 2013
|
Mar. 31, 2012
|
Dec. 31, 2012
|
Dec. 31, 2011
|
|
|
Stock Incentive Plan To Employees And Directors [Member]
|
||||
| Expected life (years) minimum | 3 years 6 months | 3 years 6 months | 2 years 6 months | |
| Expected life (years) maximum | 3 years 9 months | 3 years 6 months | 3 years 9 months 18 days | |
| Expected volatility minimum | 46.30% | 44.20% | 44.20% | |
| Expected volatility maximum | 46.50% | 44.20% | 50.90% | |
| Weighted-average volatility | 46.50% | 44.20% | 49.00% | |
| Risk-free interest rate, Minimum | 0.36% | 0.56% | 0.31% | |
| Risk-free interest rate, Maximum | 0.44% | 0.60% | 0.60% | |
| Dividend yield | 0.00% | 0.00% | 0.00% | |
| Expected forfeiture rate | 3.90% | 2.00% | 1.70% | |