Financial Instruments

12 Months Ended

Dec. 31, 2019

Cash, Cash Equivalents And Marketable Securities [Abstract]

Cash, Cash Equivalents, and Marketable Securities [Text Block]

Financial Instruments

Cash, Cash Equivalents, and Marketable Securities

The following table summarizes the Company’s cash, cash equivalents, and marketable securities and the fair value categorization of the financial instruments measured at fair value on a recurring basis:

	As of December 31,
	2019		2018
	(In thousands)
Cash	$	33,238	$	37,190
Time deposits	3,924		3,810
Money market funds (Level 1)	149,624		120,832
Debt securities issued by the U.S. Treasury (Level 1)	1,040,678		1,117,175
Total	$	1,227,464	$	1,279,007
Cash and cash equivalents	$	508,196	$	357,415
Restricted cash (included in Other long-term assets)	9,405		9,338
Total Cash, cash equivalents, and restricted cash	517,601		366,753
Marketable securities	709,863		912,254
Total	$	1,227,464	$	1,279,007

The fair value of the debt securities held as of December 31, 2019 was $1.04 billion, including less than $0.2 million of gross and net unrealized gains. All of the debt securities held as of December 31, 2019 have contractual maturities of less than one year.

Fair Value Measurements

The fair value of the Company’s investments in money market funds approximates their face value. Such instruments are classified as Level 1 and are included in Cash and cash equivalents.

The fair value of the debt securities consisting of U.S. Treasury bills is based on their quoted market prices and are classified as Level 1. Debt securities purchased with original maturities in excess of three months are included in Marketable securities. Debt securities purchased with original maturities less than three months are included in Cash and cash equivalents.

As of December 31, 2019, the Company’s other financial instruments include cash, accounts receivable, restricted cash, and accounts payable whose carrying values approximated their fair values. The fair values of the Company’s senior notes due 2023 (the “2023 Senior Notes”), the senior notes due 2025 (the “2025 Senior Notes”), and the senior notes due 2027 (the “2027 Senior Notes”) were $762.8 million, $552.3 million, and $581.9 million, respectively, as of December 31, 2019. The fair values of these debt instruments are based on available market information from public data sources and are classified as Level 2.