Cash and Investments in Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2020

Cash and Cash Equivalents [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
	December 31, 2020		December 31, 2019
Cash and cash equivalents	$	198,955	$	96,363
Short-term investments	862,941		1,228,499
Long-term investments	136,662		279,119
Total cash and investments in marketable securities	$	1,198,558	$	1,603,981

Portfolio of Cash and Investments in Marketable Securities

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

	Fair Value Hierarchy Level	December 31, 2020								December 31, 2019
		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value		Fair Value
Corporate notes and bonds	2	$	686,543	$	1,035	$	(109)	$	687,469	$	1,132,182
Corporate commercial paper	2	313,520		44		(67)		313,497		375,473
Obligations of U.S. government agencies	2	2,380		2		—		2,382		—
Available-for-sale investments		1,002,443		1,081		(176)		1,003,348		1,507,655
Money market funds	1							179,302		83,546
Certificate of deposit	N/A							9,623		6,951
Cash	N/A							6,285		5,829
Total cash and investments in marketable securities								$	1,198,558	$	1,603,981