CASH AND INVESTMENTS

Cash, Cash Equivalents and Restricted Cash

A reconciliation of Cash, cash equivalents, and restricted cash reported within our Consolidated Balance Sheets to the amount reported within the accompanying Consolidated Statements of Cash Flows was as follows (in thousands):



	December 31, 2018		December 31, 2017		December 31, 2016
Cash and cash equivalents	$	314,775	$	183,164	$	151,686
Restricted cash included in short-term restricted cash and investments	—		504		—
Restricted cash included in long-term restricted cash and investments	1,100		4,646		4,150
Cash, cash equivalents, and restricted cash as reported within the accompanying Consolidated Statements of Cash Flows	$	315,875	$	188,314	$	155,836

Restricted cash includes certificates of deposit used to collateralize letters of credit and, in prior periods, a purchasing card program.

Cash and Investments

Cash and investments by security type were as follows (in thousands):



	December 31, 2018
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Investments available-for-sale:
Money market funds	$	47,744	$	—	$	—		$	47,744
Commercial paper	381,134		—		(1		)	381,133
Corporate bonds	344,741		180		(857		)	344,064
U.S. Treasury and government sponsored enterprises	55,224		2		(25		)	55,201
Total investments available-for-sale	828,843		182		(883		)	828,142
Cash and restricted cash	6,883		—		—			6,883
Certificates of deposit	16,596		—		—			16,596
Total cash and investments	$	852,322	$	182	$	(883	)	$	851,621



	December 31, 2017
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Investments available-for-sale:
Money market funds	$	45,478	$	—	$	—		$	45,478
Commercial paper	199,647		—		—			199,647
Corporate bonds	179,336		18		(332		)	179,022
U.S. Treasury and government sponsored enterprises	16,295		—		(32		)	16,263
Total investments available-for-sale	440,756		18		(364		)	440,410
Cash and restricted cash	3,268		—		—			3,268
Certificates of deposit	13,498		—		—			13,498
Total cash and investments	$	457,522	$	18	$	(364	)	$	457,176

Gains and losses on the sales of investments available-for-sale were nominal or zero during the years ended December 31, 2018, 2017 and 2016.

The fair value of gross unrealized losses on investments available-for-sale in an unrealized loss position were as follows (in thousands):



	December 31, 2018
	In an Unrealized Loss Position Less than 12 Months					In an Unrealized Loss Position 12 Months or Greater					Total
	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Corporate bonds	$	236,162	$	(606	)	$	39,627	$	(251	)	$	275,789	$	(857	)
U.S. Treasury and government sponsored enterprises	28,105		(16		)	9,182		(9		)	37,287		(25		)
Commercial paper	7,091		(1		)	—		—			7,091		(1		)
Total	$	271,358	$	(623	)	$	48,809	$	(260	)	$	320,167	$	(883	)



	December 31, 2017
	In an Unrealized Loss Position Less than 12 Months					In an Unrealized Loss Position 12 Months or Greater					Total
	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Corporate bonds	$	140,746	$	(296	)	$	20,047	$	(36	)	$	160,793	$	(332	)
U.S. Treasury and government sponsored enterprises	13,611		(23		)	2,651		(9		)	16,262		(32		)
Total	$	154,357	$	(319	)	$	22,698	$	(45	)	$	177,055	$	(364	)

There were 199 and 134 investments in an unrealized loss position as of December 31, 2018 and 2017, respectively. During the years ended December 31, 2018, 2017 and 2016 we did not record any other-than-temporary impairment charges on our available-for-sale securities. Based upon our quarterly impairment review, we determined that the unrealized losses were not attributed to credit risk, but were primarily associated with changes in interest rates. Based on the scheduled maturities of our investments and our determination that it was more likely than not that we will hold these investments for a period of time sufficient for a recovery of our cost basis, we concluded that the unrealized losses in our investment securities were not other-than-temporary.

The fair value of investments available-for-sale by contractual maturity were as follows (in thousands):



	December 31,
	2018		2017
Maturing in one year or less	$	674,455	$	377,155
Maturing after one year through five years	153,687		63,255
Total investments available-for-sale	$	828,142	$	440,410

Other Cost Method Equity Investments

During the years ended December 31, 2018, 2017 and 2016, we recognized gains of $0.2 million, $3.0 million and $2.5 million, respectively, related to the August 2016 sale of our 9% interest in Akarna Therapeutics, Ltd. (Akarna) to Allergan Holdco UK Limited (Allergan). We acquired our interest in Akarna in 2015 in exchange for intellectual property rights related to the Exelixis discovered compound XL335. The gain on sale was included in Other, net in the accompanying Consolidated Statements of Operations. We are eligible to earn additional such gains in the future as Allergan continues its development of XL335.

Related Party Transactions

During 2018, BlackRock, Inc. (BlackRock), a global provider of investment, advisory and risk management solutions, reported that their beneficial ownership increased to more than 10% of our outstanding common stock. BlackRock manages a portion of our cash and investments portfolio. As of December 31, 2018 and 2017, respectively, the fair value of cash and investments managed by BlackRock was $298.5 million and $141.0 million, which included $3.0 million and $1.0 million invested in the BlackRock Liquidity Money Market Fund. We incurred $0.2 million in fees for BlackRock advisory services performed during the year ended December 31, 2018.