Financial Instruments

6 Months Ended

Jun. 30, 2019

Financial Instruments, Owned, at Fair Value [Abstract]

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:



	June 30,		December 31,
	2019		2018
	(In thousands)
Cash	$	26,451	$	37,190
Time deposits	4,134		3,810
Money market funds (Level 1)	104,275		120,832
Debt securities issued by the U.S. Treasury (Level 1)	1,099,456		1,117,175
Total	$	1,234,316	$	1,279,007

Cash and cash equivalents	$	751,580	$	357,415
Restricted cash (included in Other long-term assets)	9,374		9,338
Total Cash, cash equivalents, and restricted cash	760,954		366,753
Marketable securities	473,362		912,254
Total	$	1,234,316	$	1,279,007

The fair value of the debt securities held as of June 30, 2019 was $1.10 billion, including less than $0.1 million of gross and net unrealized gains. All of the debt securities held as of June 30, 2019 are scheduled to mature in 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 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. Debt securities purchased with original maturities in excess of three months are included in Marketable securities. The fair value of all of these financial instruments are classified as Level 1 in the fair value hierarchy.

The Company’s other financial instruments include cash, accounts receivable, restricted cash, and accounts payable. As of June 30, 2019, the carrying value of these financial instruments approximated their fair value. The fair values of the senior notes due 2023, 2025, and 2027 were $763.2 million, $537.2 million, and $576.6 million, respectively, as of June 30, 2019. The fair values of these debt instruments are based on available market information from public data sources and are classified as Level 2.