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Shareholders' Equity (Details) (USD $)	6 Months Ended
Shareholders' Equity (Details) (USD $)	Jul. 28, 2012	Jul. 30, 2011
Employee Stock Option [Member]
Weighted- average assumptions for determining Fair value
Expected life	4 years	4 years
Expected volatility		83.00%
Expected dividends
Employee Stock Option [Member] \| Maximum [Member]
Weighted- average assumptions for determining Fair value
Expected volatility	88.00%
Risk-free interest rate	0.92%	1.61%
Employee Stock Option [Member] \| Minimum [Member]
Weighted- average assumptions for determining Fair value
Expected volatility	87.00%
Risk-free interest rate	0.53%	1.24%
ESPP [Member]
Weighted- average assumptions for determining Fair value
Expected life	6 months	6 months
Expected volatility	71.00%	54.00%
Risk-free interest rate	0.15%	20.00%
Expected dividends

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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