Cash and Cash Equivalents, Restricted Cash and Marketable Securities

Cash and Cash Equivalents

The Company considers all highly liquid investments with original maturities of ninety days or less to be cash equivalents. These investments, along with cash deposited in institutional money market funds, commercial paper, regular interest bearing and non-interest bearing depository accounts, are classified as cash and cash equivalents in the accompanying condensed consolidated balance sheet. The following table summarizes the Company’s cash and cash equivalents:



	September 30, 2017		December 31, 2016		Recurring Fair Value Measurement
	(in thousands)
Cash and cash equivalents:
Cash	$	140,957	$	102,194
Money market funds	181,524		266,478		Level 1
Commercial paper	7,580		2,495		Level 2
Total cash and cash equivalents	$	330,061	$	371,167

Restricted Cash

The Company is required to maintain a minimum cash reserve for debt service related to its $1.8 billion loan facility (as amended to date, the “Credit Facility”) (see Note 4). As of September 30, 2017 and December 31, 2016, the Company’s restricted cash balance, which includes a minimum cash reserve for debt service related to the Credit Facility and the interest earned on these amounts, was $102.1 million and $113.1 million, respectively.

Marketable Securities

Marketable securities consist of fixed-income debt securities and commercial paper with an original maturity in excess of ninety days. These investments are classified as available-for-sale and are included in marketable securities within current assets in the accompanying condensed consolidated balance sheets. All investments are carried at fair value. Unrealized gains and losses, net of taxes, are reported as a component of other comprehensive income or loss. The specific identification method is used to determine the cost basis of the marketable securities sold. There were no material realized gains or losses on the sale of marketable securities for the nine months ended September 30, 2017 and 2016. The Company regularly monitors and evaluates the fair value of its investments to identify other-than-temporary declines in value. The Company determined that the decline in fair value of its investments is temporary at September 30, 2017 as the Company does not intend to sell these securities, and it is not likely that the Company will be required to sell the securities before the recovery of their amortized cost basis.

The following tables summarize the Company’s marketable securities:



	As of September 30, 2017
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value		Recurring Fair Value Measurement
	(in thousands)
Fixed-income debt securities	$	18,042	$	17	$	(5	)	$	18,054	Level 2
U.S. treasury notes	2,249		—		(3		)	2,246		Level 2
Total marketable securities	$	20,291	$	17	$	(8	)	$	20,300



	As of December 31, 2016
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value		Recurring Fair Value Measurement
	(in thousands)
Fixed-income debt securities	$	30,037	$	14	$	(11	)	$	30,040	Level 2
U.S. treasury notes	9,283		7		(2		)	9,288		Level 2
Total marketable securities	$	39,320	$	21	$	(13	)	$	39,328

The following table presents the contractual maturities of the Company’s marketable securities:



	As of September 30, 2017				As of December 31, 2016
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
	(in thousands)
Mature within one year	$	20,041	$	20,051	$	32,776	$	32,788
Mature after one year and within three years	250		249		6,544		6,540
Total	$	20,291	$	20,300	$	39,320	$	39,328