Cash and Investments in Marketable Securities (Tables)

9 Months Ended

Sep. 30, 2019

Fair Value Disclosures [Abstract]

Cash and Investments in Marketable Securities, Including Cash Equivalents

Cash and investments in marketable securities, including cash equivalents, are as follows (in thousands):

	Estimated Fair Value at
	September 30, 2019		December 31, 2018
Cash and cash equivalents	$	81,224	$	194,905
Short-term investments	1,414,448		1,140,445
Long-term investments	231,082		582,889
Total cash and investments in marketable securities	$	1,726,754	$	1,918,239

Portfolio of Cash and Investments in Marketable Securities

Our portfolio of cash and investments in marketable securities includes (in thousands):

		Estimated Fair Value at
	Fair Value Hierarchy Level	September 30, 2019		December 31, 2018
Corporate notes and bonds	2	$	1,163,575	$	1,288,986
Corporate commercial paper	2	482,468		498,048
Obligations of U.S. government agencies	2	—		12,977
Available-for-sale investments		1,646,043		1,800,011
Money market funds	1	45,674		105,656
Certificate of deposit	N/A	6,871		6,760
Cash	N/A	28,166		5,812
Total cash and investments in marketable securities		$	1,726,754	$	1,918,239