Stock-Based Compensation (Schedule Of Weighted-Average Assumptions Used In The Black-Scholes Valuation Model For Stock Options Granted) (Details)	3 Months Ended	9 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011	Dec. 31, 2010
Stock-Based Compensation [Abstract]
Expected volatility	79.70%	61.40%	69.70%	65.50%
Risk-free interest rate	1.10%	2.40%	1.80%	2.10%
Expected life (years)	5.9	6.1	5.9	6.1
Dividend yield	None	None	None	None

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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