DEBT SECURITIES (Tables)

6 Months Ended

Jun. 30, 2020

Investments, Debt and Equity Securities [Abstract]

Schedule of marketable securities

Debt securities consisted of the following (in thousands):

	June 30, 2020		December 31, 2019
Commercial paper	$	—	$	17,152
Corporate debt securities	210,205		306,436
Securities of government sponsored entities	10,001		12,500
Total debt securities:	$	220,206	$	336,088

Debt securities available for sale

The following is a summary of short-term debt securities classified as available-for-sale as of June 30, 2020 (in thousands):

	Remaining Contractual Maturity (in years)	Amortized Cost		Unrealized Gains		Unrealized Losses		Aggregate Estimated Fair Value
Commercial paper	Less than 1	$	—	$	—	$	—	$	—
Corporate debt securities	Less than 1	132,352		770		—		133,122
Total maturity less than 1 year		132,352		770		—		133,122
Corporate debt securities	1 to 2	76,244		848		(9)		77,083
Securities of government-sponsored entities	1 to 2	10,000		1		—		10,001
Total maturity 1 to 2 years		86,244		849		(9)		87,084
Total available-for-sale securities		$	218,596	$	1,619	$	(9)	$	220,206

The following is a summary of short-term debt securities classified as available-for-sale as of December 31, 2019 (in thousands):

	Remaining Contractual Maturity (in years)	Amortized Cost		Unrealized Gains		Unrealized Losses		Aggregate Estimated Fair Value
Commercial paper	Less than 1	$	17,136	$	16	$	—	$	17,152
Corporate debt securities	Less than 1	191,770		582		(10)		192,342
Total maturity less than 1 year		208,906		598		(10)		209,494
Corporate debt securities	1 to 2	113,799		351		(56)		114,094
Securities of government-sponsored entities	1 to 2	12,501		—		(1)		12,500
Total maturity 1 to 2 years		126,300		351		(57)		126,594
Total available-for-sale securities		$	335,206	$	949	$	(67)	$	336,088

Schedule of securities in an unrealized loss position

The following is a summary of available-for-sale debt securities in an unrealized loss position with no credit losses reported as of June 30, 2020 (in thousands):

	Less Than 12 Months				12 Months or Greater				Total
Description of Securities	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Commercial paper	$	—	$	—	$	—	$	—	$	—	$	—
Corporate debt securities	5,015		9		—		—		5,015		9
Securities of government-sponsored entities	—		—		—		—		—		—
Total	$	5,015	$	9	$	—	$	—	$	5,015	$	9

The following is a summary of available-for-sale debt securities in an unrealized loss position with no credit losses reported as of December 31, 2019 (in thousands):

	Less Than 12 Months				12 Months or Greater				Total
Description of Securities	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Commercial paper	$	—	$	—	$	—	$	—	$	—	$	—
Corporate debt securities	74,151		64		7,509		2		81,660		66
Securities of government-sponsored entities	5,000		1		—		—		5,000		1
Total	$	79,151	$	65	$	7,509	$	2	$	86,660	$	67