Stock Plans (Details 1) (USD $)	3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended
Jun. 30, 2012 Employee Stock Purchase Plan	Jun. 30, 2012 Employee Stock Purchase Plan	Jun. 30, 2013 Restricted Stock Awards	Jun. 30, 2013 Restricted Stock Awards
Schedule of stock options and employee stock purchase plan weighted-average assumptions
Expected dividends	0.00%	0.00%	0.00%	0.00%
Exercise price	$ 16.24	$ 16.24	$ 6.80	$ 6.80
Expected volatility	63.00%	63.00%	68.60%	68.60%
Average risk-free interest rate	0.06%	0.06%	1.10%	1.10%
Expected life/term (in years)	6 months	6 months	4 years 9 months 18 days	4 years 9 months 18 days
Fair value per share	$ 5.26	$ 5.26	$ 3.72	$ 3.72

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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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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