Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation and Employee Benefit Plans Fair Value of Employee Stock Purchase Rights (Details)

v2.4.0.8
Stock-Based Compensation and Employee Benefit Plans Fair Value of Employee Stock Purchase Rights (Details) (Two Thousand Ten Employee Stock Purchase Plan [Member], USD $)
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Dividend yield 0.00% 0.00% 0.00%
Expected life (years) 6 months 6 months 6 months
Minimum [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Weighted-average grant date fair value per share (usd per share) $ 1.85 $ 1.28 $ 1.89
Risk-free interest rate 0.09% 0.14% 0.05%
Volatility 34.24% 46.60% 45.70%
Maximum [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Weighted-average grant date fair value per share (usd per share) $ 2.09 $ 1.42 $ 2.46
Risk-free interest rate 0.10% 0.15% 0.07%
Volatility 41.58% 55.74% 72.84%