Description of Business and Summary of Significant Accounting Policies (Details 6) (Options to purchase common stock)
In Thousands, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Options to purchase common stock
   
Anti-dilutive weighted-average common stock equivalents excluded from the calculation of diluted net income per share    
Total (in shares) 4,815 4,853