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Stockholders' Equity and Share-Based Compensation - Valuation Assumptions of Share-Based Awards (Details) (USD $)
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected dividend yield 0.00%    
Stock Options
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected volatility 44.00% 50.00% 50.00%
Risk-free interest rate 1.60% 0.70% 0.80%
Expected option life in years 5 years 5 years 5 years
Expected dividend yield 0.00% 0.00% 0.00%
Weighted average per share grant date fair value $ 3.66 $ 3.57 $ 3.04
ESPP Purchase Rights
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected volatility 28.00% 34.00% 35.00%
Risk-free interest rate 0.10% 0.10% 0.10%
Expected option life in years 6 months 6 months 6 months
Expected dividend yield 0.00% 0.00% 0.00%
Weighted average per share grant date fair value $ 1.89 $ 1.77 $ 1.72