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Stock Based Compensation Stock Based Compensation, Fair Value assumptions (Details) (USD $)
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12 Months Ended | ||
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Dec. 31, 2013
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Dec. 31, 2012
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Dec. 31, 2011
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| Stock based Compensation, Fair Value Assumptions [Abstract] | |||
| Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate | 0.00% | 0.00% | 0.00% |
| Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate | 1.60% | 0.90% | 1.20% |
| Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate | 64.80% | 63.90% | 64.20% |
| Fair Value Assumptions, Expected Term | 6 years 1 month 27 days | 6 years 1 month 6 days | 4 years 1 month 6 days |
| Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value | $ 1.39 | $ 1.85 | $ 4.05 |