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The Company, Basis of Presentation and Summary of Significant Accounting Policies (Details)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Weighted-average risk-free interest rate	0.74%	1.83%	2.39%
Weighted-average expected life of options	5 years	5 years	5 years
Expected dividend yield	0.00%	0.00%	0.00%
Weighted-average expected volatility	89.73%	87.82%	93.95%
Anticipated forfeiture rate	12.00%	3.00%

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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