Quarterly report pursuant to Section 13 or 15(d)

Marketable Securities - Continuous Unrealized Loss Position (Details)

v3.19.1
Marketable Securities - Continuous Unrealized Loss Position (Details)
$ in Thousands
Mar. 31, 2019
USD ($)
Debt Securities, Available-for-sale [Line Items]  
Fair Value $ 758,525
Gross Unrealized Losses, less than 12 months (4,101) [1]
Gross Unrealized Losses, 12 months or more 4,100
Corporate Debt Securities [Member]  
Debt Securities, Available-for-sale [Line Items]  
Fair Value 397,009
Gross Unrealized Losses, less than 12 months (2,076) [1]
U.S. Treasury securities  
Debt Securities, Available-for-sale [Line Items]  
Fair Value 187,080
Gross Unrealized Losses, less than 12 months (1,203) [1]
U.S. Government agency securities  
Debt Securities, Available-for-sale [Line Items]  
Fair Value 163,445
Gross Unrealized Losses, less than 12 months (776) [1]
Sovereign securities  
Debt Securities, Available-for-sale [Line Items]  
Fair Value 10,991
Gross Unrealized Losses, less than 12 months $ (46) [1]
[1] As of March 31, 2019, we had investments in a continuous loss position for 12 months or more with a gross amount $4.1 million.