Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2019

Fair Value Disclosures [Abstract]

Assets Measured at Fair Value on Recurring Basis

The following table presents our financial assets measured and recorded at fair value on a recurring basis using the above input categories:

	As of June 30, 2019
	Level 1		Level 2		Level 3		Total
	(in thousands)
Description:
Assets:
Money market funds	$	108,526	$	—	$	—	$	108,526
U.S. government agencies	45,838		—		—		45,838
Commercial paper	—		17,292		—		17,292
Corporate bonds	—		45,606		—		45,606
Agency bonds	—		21,098		—		21,098
Asset-backed securities	—		7,984		—		7,984
Total assets	$	154,364	$	91,980	$	—	$	246,344

	As of December 31, 2018
	Level 1		Level 2		Level 3		Total
	(in thousands)
Description:
Assets:
Money market funds	$	55,646	$	—	$	—	$	55,646
U.S. government agencies	74,481		—		—		74,481
Commercial paper	—		57,554		—		57,554
Corporate bonds	—		48,495		—		48,495
Agency bonds	—		19,087		—		19,087
Asset-backed securities	—		7,483		—		7,483
Total assets	$	130,127	$	132,619	$	—	$	262,746

Schedule of Available-for-sale Securities Reconciliation

Our investments, which are all classified as available-for-sale, consisted of the following:

	As of June 30, 2019
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
	(in thousands)
Description:
U.S. government agencies	$	45,695	$	143	$	—		$	45,838
Commercial paper	17,291		1		—			17,292
Corporate bonds	45,483		124		(1		)	45,606
Agency bonds	21,026		72		—			21,098
Asset-backed securities	7,972		13		(1		)	7,984
Total assets	$	137,467	$	353	$	(2	)	$	137,818

	As of December 31, 2018
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
	(in thousands)
Description:
U.S. government agencies	$	71,480	$	20	$	(17	)	$	71,483
Commercial paper	57,554		—		—			57,554
Corporate bonds	48,532		15		(52		)	48,495
Agency bonds	19,077		16		(6		)	19,087
Asset-backed securities	7,490		—		(7		)	7,483
Total assets	$	204,133	$	51	$	(82	)	$	204,102