Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2019

Fair Value Disclosures [Abstract]

Schedule of Fair Value, Assets Measured on Recurring Basis

The following tables set forth the Company’s financial instruments that were measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands):

	Fair Value Measurements at June 30, 2019
	Total		Level 1		Level 2		Level 3
Assets
Money market funds	$	64,578	$	64,578	$	—	$	—
Corporate securities and commercial paper		60,268		—		60,268		—
U.S. government treasury and agency securities		99,552		—		99,552		—
	$	224,398	$	64,578	$	159,820	$	—

	Fair Value Measurements at December 31, 2018
	Total		Level 1		Level 2		Level 3
Assets
Money market funds	$	45,017	$	45,017	$	—	$	—
U.S. government treasury and agency securities		103,940		—		103,940		—
Corporate securities and commercial paper		110,768		—		110,768		—
	$	259,725	$	45,017	$	214,708	$	—

Schedule of Investments Classified as Available for Sale Securities with Contractual Maturities

Classified as (with contractual maturities):

	June 30, 2019		December 31, 2018
Cash and Cash equivalents	$	76,068	$	71,064
Short-term investments (due within one year)		148,330		185,480
Long-term investments (due between one and two years)		—		3,181
	$	224,398	$	259,725

Schedule of Available for Sale Securities at Fair Value Measurements

	Fair Value Measurements at June 30, 2019
	Amortized Cost		Unrealized Gain		Unrealized Loss		Fair Value
Money market funds	$	64,578	$	—	$	—	$	64,578
Corporate securities and commercial paper		60,241		27		—		60,268
U.S. government treasury and agency securities		99,468		84		—		99,552
	$	224,287	$	111	$	—	$	224,398

	Fair Value Measurements at December 31, 2018
	Amortized Cost		Unrealized Gain		Unrealized Loss			Fair Value
Money market funds	$	45,017	$	—	$	—		$	45,017
U.S. government treasury and agency securities		103,957		—		(17	)		103,940
Corporate securities and commercial paper		110,859		—		(91	)		110,768
	$	259,833	$	—	$	(108	)	$	259,725