Marketable Securities

Available-for-sale marketable securities and cash and cash equivalents as of September 30, 2018 and December 31, 2017 consist of the following (in thousands):



	September 30, 2018
	Amortized Cost Value		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Cash and cash equivalents:
Cash	$	15,236	$	—	$	—		$	15,236
Money market funds	46,778		—		—			46,778
Total	$	62,014	$	—	$	—		$	62,014

Marketable securities:
Domestic corporate debt securities	$	155,346	$	—	$	(643	)	$	154,703
Agency bonds	59,981		—		(329		)	59,652
Total	$	215,327	$	—	$	(972	)	$	214,355



	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 funds	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

There were no available-for-sale marketable securities that had been in an unrealized loss position for more than 12 months as of September 30, 2018 or December 31, 2017, respectively. There were 29 marketable securities with an aggregate fair value of $214.4 million in an unrealized loss position for less than 12 months as of September 30, 2018. There were 38 marketable securities with an aggregate fair value of $299.2 million in an unrealized loss position for less than 12 months as of December 31, 2017. The Company considered the decrease 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 at maturity, the Company did not consider these investments to be other-than-temporarily impaired as of September 30, 2018.

As of September 30, 2018, the aggregate fair value of marketable securities maturing within one year and after one year through two years was $172.1 million and $42.2 million, respectively.