XML 57 R46.htm IDEA: XBRL DOCUMENT v3.4.0.3
Investments (Details) - USD ($)
$ in Thousands
Mar. 31, 2016
Dec. 31, 2015
Summary of Investments    
Available-for-sale securities, Amortized Cost $ 276,307 $ 238,568
Available-for-sale securities, Gross Unrealized Gains 641 5
Available-for-sale securities, Gross Unrealized Losses (132) (947)
Available-for-sale securities, Estimated Fair Value 276,816 237,626
Corporate debt securities    
Summary of Investments    
Available-for-sale securities due in one year or less, Amortized Cost 56,886 27,964
Available-for-sale securities due in one to three years, Amortized Cost 193,452 173,652
Available-for-sale securities due in one year or less, Gross Unrealized Gains 7  
Available-for-sale securities due in one to three years, Gross Unrealized Gains 596 3
Available-for-sale securities due in one year or less, Gross Unrealized Losses (43) (38)
Available-for-sale securities due in one to three years, Gross Unrealized Losses (89) (904)
Available-for-sale securities due in one year or less, Estimated Fair Value 56,850 27,926
Available-for-sale securities due in one to three years, Estimated Fair Value 193,959 172,751
Commercial Paper    
Summary of Investments    
Available-for-sale securities due in one year or less, Amortized Cost 18,973 34,452
Available-for-sale securities due in one year or less, Gross Unrealized Gains 4 2
Available-for-sale securities due in one year or less, Gross Unrealized Losses   (5)
Available-for-sale securities due in one year or less, Estimated Fair Value 18,977 34,449
Municipal securities    
Summary of Investments    
Available-for-sale securities due in one year or less, Amortized Cost 2,500 2,500
Available-for-sale securities due in one year or less, Gross Unrealized Gains 2  
Available-for-sale securities due in one year or less, Estimated Fair Value 2,502 $ 2,500
U.S. treasury and government agency securities    
Summary of Investments    
Available-for-sale securities due in one year or less, Amortized Cost 4,496  
Available-for-sale securities due in one year or less, Gross Unrealized Gains 32  
Available-for-sale securities due in one year or less, Estimated Fair Value $ 4,528