Marketable Securities

Available-for-sale marketable securities and cash and cash equivalents consist of the following (in thousands):



	December 31, 2017
	Amortized Cost Value		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Cash and cash equivalents:
Cash	$	73,302	$	—	$	—		$	73,302
Money market	325		—		—			325
Domestic corporate commercial paper	44,937		—		—			44,937
Total	$	118,564	$	—	$	—		$	118,564
Marketable securities:
Domestic corporate debt securities	$	207,320	$	1	$	(235	)	$	207,086
Domestic corporate commercial paper	29,844		—		(7		)	29,837
Agency bonds	74,842		—		(73		)	74,769
Total	$	312,006	$	1	$	(315	)	$	311,692



	December 31, 2016
	Amortized Cost Value		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Cash and cash equivalents:
Cash	$	77,443	$	—	$	—		$	77,443
Money market funds	173,631		—		—			173,631
Domestic corporate commercial paper	5,487		—		—			5,487
Domestic corporate debt securities	2,006		—		—			2,006
Total	$	258,567	$	—	$	—		$	258,567
Marketable securities:
Domestic corporate debt securities	$	19,317	$	—	$	(2	)	$	19,315
Domestic corporate commercial paper	31,852		78		—			31,930
Asset-backed securities	22,639		—		(4		)	22,635
Total	$	73,808	$	78	$	(6	)	$	73,880

There were no debt securities that had been in an unrealized loss position for more than 12 months as of December 31, 2017 or December 31, 2016. There were 38 debt securities in an unrealized loss position for less than 12 months at December 31, 2017 and there were 13 debt securities that had been in an unrealized loss position for less than 12 months at December 31, 2016. The aggregate unrealized loss on these securities as of December 31, 2017 and 2016 was approximately $315 thousand and $6 thousand, respectively, and the fair value was $299.2 million and $35.7 million, respectively. The Company considered the decline in market value for these securities to be primarily attributable to current economic conditions. As it was not more likely than not that the Company would be required to sell these securities before the recovery of their amortized cost basis, which may be maturity, the Company did not consider these investments to be other-than-temporarily impaired as of December 31, 2017 and 2016.

As of December 31, 2017, marketable securities consisted of investments that mature within one year, with the exception of certain corporate debt securities and agency bonds, which have maturities within 2 years and an aggregate fair value of $177.0 million.