Cash, Cash Equivalents and Marketable Securities

3 Months Ended

Mar. 31, 2019

Cash and Cash Equivalents [Abstract]

Cash, Cash Equivalents, and Marketable Securities

Cash, Cash Equivalents and Marketable SecuritiesThe following table summarizes the amortized cost and the estimated fair value of our cash, cash equivalents and marketable securities as of March 31, 2019 and December 31, 2018 (in thousands):

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
March 31, 2019
Current assets:
Cash	$	11,353	$	—	$	—	$	11,353
Cash equivalents:
Commercial paper	15,945		—		—		15,945
Money market funds	21,005		—		—		21,005
U.S. Treasuries	9,985		—		—		9,985
Total cash equivalents	46,935		—		—		46,935
Total cash and cash equivalents	58,288		—		—		58,288
Marketable securities:
Commercial paper	176,705		—		—		176,705
Corporate debt securities	83,904		231		(19)		84,116
Certificate of deposits	48,744		—		—		48,744
U.S. Treasuries	112,681		161		—		112,842
Total marketable securities	422,034		392		(19)		422,407
Total cash, cash equivalents and marketable securities	$	480,322	$	392	$	(19)	$	480,695

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
December 31, 2018
Current assets:
Cash and cash equivalents:
Cash	$	5,222	$	—	$	—	$	5,222
Money market funds	63,232		—		—		63,232
Total cash and cash equivalents	68,454		—		—		68,454
Marketable securities:
Commercial paper	152,940		—		—		152,940
Corporate debt securities	60,622		58		(75)		60,605
Certificate of deposits	128,647		—		—		128,647
U.S. Treasury securities	103,521		31		(11)		103,541
Total marketable securities	445,730		89		(86)		445,733
Total cash, cash equivalents and marketable securities	$	514,184	$	89	$	(86)	$	514,187

The following table summarizes the cost and fair value of marketable securities based on stated effective maturities as of March 31, 2019 (in thousands):

	Amortized Cost		Fair Value
Due within one year	$	356,954	$	357,120
Due between one and two years	65,080		65,287
Total	$	422,034	$	422,407

There have been no significant realized gains or losses on available-for-sale securities for the periods presented. As of March 31, 2019, available-for-sale debt securities that were in a continuous loss position but were not deemed to be other than temporarily impaired were not material.

See Note 5 for further information regarding the fair value of our financial instruments.