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Stock Options, Employee Stock Purchase Plan and Restricted Stock (Details) - Weighted-average Assumptions for Stock Options - $ / shares
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Assumptions used in estimating fair value of stock options      
Expected life (in years) 4 years 8 months 23 days 4 years 9 months 18 days 4 years 1 month 6 days
Dividend yield 0.00% 0.00% 0.00%
Fair value per stock option (in Dollars per share) $ 11.13 $ 14.59 $ 12.89
Minimum [Member]      
Assumptions used in estimating fair value of stock options      
Expected volatility 46.00% 42.00% 40.00%
Risk-free interest rate 0.90% 1.50% 0.90%
Maximum [Member]      
Assumptions used in estimating fair value of stock options      
Expected volatility 50.00% 47.00% 71.00%
Risk-free interest rate 1.80% 1.60% 2.20%