Cash, Cash Equivalents and Marketable Securities (Tables)

9 Months Ended

Sep. 30, 2019

Cash and Cash Equivalents [Abstract]

Amortized Cost and Fair Value of Cash, Cash Equivalents and Marketable Securities

The following tables summarize the amortized cost and the estimated fair value of our cash, cash equivalents and marketable securities as of September 30, 2019 and December 31, 2018 (in thousands):

	September 30, 2019
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Current assets:
Cash	$	23,568	$	—	$	—	$	23,568
Cash equivalents:
Commercial paper	996		—		—		996
Money market funds	8,535		—		—		8,535
Total cash equivalents	9,531		—		—		9,531
Total cash and cash equivalents	33,099		—		—		33,099
Marketable securities:
Commercial paper	86,936		—		—		86,936
Corporate debt securities	81,835		425		(3)		82,257
Certificate of deposits	52,672		—		—		52,672
Total marketable securities	221,443		425		(3)		221,865
Total cash, cash equivalents and marketable securities	$	254,542	$	425	$	(3)	$	254,964

	December 31, 2018
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Current assets:
Cash	$	5,222	$	—	$	—	$	5,222
Cash equivalents:
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

Cost and Fair Value of Marketable Securities

The following table summarizes the cost and fair value of marketable securities based on stated effective maturities as of September 30, 2019 (in thousands):

	Amortized Cost		Fair Value
Due within one year	$	168,397	$	168,490
Due between one and two years	53,046		53,375
Total	$	221,443	$	221,865