INVESTMENTS (Tables)

3 Months Ended

Mar. 31, 2020

INVESTMENTS

Schedule of marketable securities by security type

	As of March 31, 2020								As of December 31, 2019
			Gross		Gross						Gross		Gross
			Unrealized		Unrealized		Estimated				Unrealized		Unrealized		Estimated
(in thousands)	Cost		Gains		Losses		Fair Value		Cost		Gains		Losses		Fair Value
Commercial paper and corporate bonds	$	15,765	$	13	$	(37)	$	15,741	$	7,540	$	—	$	(20)	$	7,520
US government agency debt security		45,952		113		—		46,065		12,466		19		(1)		12,484
Total	$	61,717	$	126	$	(37)	$	61,806	$	20,006	$	19	$	(21)	$	20,004

Schedule of contractual maturities

	As of March 31, 2020								As of December 31, 2019
			Gross		Gross						Gross		Gross
			Unrealized		Unrealized		Estimated				Unrealized		Unrealized		Estimated
(in thousands)	Cost		Gains		Losses		Fair Value		Cost		Gains		Losses		Fair Value
Due in one year or less	$	57,157	$	110	$	(37)	$	57,230	$	20,006	$	19	$	(21)	$	20,004
Due in one through two years		4,560		16		—		4,576		—		—		—		—
Total	$	61,717	$	126	$	(37)	$	61,806	$	20,006	$	19	$	(21)	$	20,004

Unrealized Gain (Loss) on Investments

The unrealized losses and fair values of available-for-sale securities that have been in an unrealized loss position for a period of less than and greater than 12 months as of March 31, 2020 are as follows:

	As of March 31, 2020
	Securities in an unrealized loss position less than 12 months				Securities in an unrealized loss position greater than 12 months				Total
	Unrealized		Estimated		Unrealized		Estimated		Unrealized		Estimated
(in thousands)	Losses		Fair Value		Losses		Fair Value		Losses		Fair Value
Commercial paper and corporate bonds	$	(37)	$	10,176	$	—	$	—	$	(37)	$	10,176
US government agency debt security		—		—		—		—		—		—
Total	$	(37)	$	10,176	$	—	$	—	$	(37)	$	10,176

The unrealized losses and fair values of available-for-sale securities that have been in an unrealized loss position for a period of less than and greater than 12 months as of March 31, 2020 are as follows:

	As of December 31, 2019
	Securities in an unrealized loss position less than 12 months				Securities in an unrealized loss position greater than 12 months				Total
	Unrealized		Estimated		Unrealized		Estimated		Unrealized		Estimated
(in thousands)	Losses		Fair Value		Losses		Fair Value		Losses		Fair Value
Commercial paper and corporate bonds	$	(20)	$	7,520	$	—	$	—	$	(20)	$	7,520
US government agency debt security		(1)		3,497		—		—		(1)		3,497
Total	$	(21)	$	11,017	$	—	$	—	$	(21)	$	11,017