Quarterly report pursuant to Section 13 or 15(d)

Cash, Cash Equivalents and Investments - Schedule of available-for-sale investments by contractual maturity date (Details)

v2.4.1.9
Cash, Cash Equivalents and Investments - Schedule of available-for-sale investments by contractual maturity date (Details) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Adjusted Cost    
Due in one year or less $ 287,571us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost $ 282,206us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost
Due after one year through three years 99,702p_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughThreeYearsAmortizedCost 104,585p_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughThreeYearsAmortizedCost
Total 387,273us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCost 386,791us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCost
Fair Value    
Due in one year or less 287,680us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue 282,101us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue
Due after one year through three years 99,704p_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughThreeYearsFairValue 104,243p_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughThreeYearsFairValue
Total $ 387,384us-gaap_AvailableForSaleSecuritiesDebtSecurities $ 386,344us-gaap_AvailableForSaleSecuritiesDebtSecurities