Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity (Stock Option Plan Activity) (Details)

v2.4.1.9
Stockholders' Equity (Stock Option Plan Activity) (Details) (USD $)
In Thousands, except Share data, unless otherwise specified
3 Months Ended 12 Months Ended
Mar. 31, 2015
Dec. 31, 2014
Shares    
Balance as of December 31, 2014 1,800,697us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber  
Granted 243,469us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross  
Exercised (42,489)us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised  
Balance as of March 31, 2015 2,001,677us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber 1,800,697us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
Exercisable as of March 31, 2015 1,183,763us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber  
Options vested and expected to vest as of March 31, 2015 2,001,677us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber  
Weighted Average Exercise Price (in USD per share)    
Balance as of December 31, 2014 $ 28.78us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice  
Granted $ 56.40us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice  
Exercised $ 18.35us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice  
Balance as of March 31, 2015 $ 32.36us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice $ 28.78us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
Exercisable as of March 31, 2015 $ 21.39us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice  
Options vested and expected to vest as of March 31, 2015 $ 32.36us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice  
Weighted-Average Remaining Contractual Term in Years    
Weighted average remaining contractual term in years 7 years 4 months 13 days 7 years 3 months
Exercisable 6 years 5 months 12 days  
Options vested and expected to vest 7 years 4 months 13 days  
Aggregate Intrinsic Value    
Aggregate intrinsic value $ 89,578us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue $ 51,558us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue
Exercisable 65,956us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1  
Options vested and expected to vest $ 89,578us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue