Quarterly report pursuant to Section 13 or 15(d)

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

v3.2.0.727
Stock-Based Compensation and Employee Benefit Plans - Fair Value of Employee Stock Purchase Rights (Details) - Employee Stock Purchase Rights [Member] - $ / shares
6 Months Ended
Jun. 30, 2015
Jun. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Weighted-average grant date fair value per share $ 2.25 $ 2.47
Risk-free interest rate 0.09% 0.05%
Dividend yield 0.00% 0.00%
Expected life (years) 6 months 6 months
Volatility 32.65% 47.75%