Capital Stock (Details 2)	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Maximum [Member]
Options to Non-Employees
Contractual option life (in years)	5.14	5.33	5.14	5.39
Maximum [Member] \| Options to Non-Employees [Member]
Options to Non-Employees
Contractual option life (in years)				6.84
Minimum [Member]
Options to Non-Employees
Contractual option life (in years)	1.78	2.99	1.78	2.99
Minimum [Member] \| Options to Non-Employees [Member]
Options to Non-Employees
Contractual option life (in years)				6
Options to Non-Employees [Member]
Options to Non-Employees
Average risk-free interest rate	0.00%	3.12%	2.38%	3.10%
Contractual option life (in years)	0	6.84	6.00
Expected volatility	0.00%	61.00%	50.00%	61.00%
Dividend yield	0.00%	0.00%	0.00%	0.00%

The period of time an equity-based award is expected to be outstanding. An equity-based award's expected term is generally determined based on, among other factors, the instrument's contractual term and the effects of employees' expected exercise and post-vesting employment termination behavior.

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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.

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