INVESTMENTS (Tables)

12 Months Ended

Dec. 31, 2019

Investments, Debt and Equity Securities [Abstract]

Schedule of cash, cash equivalents and short-term investments

At December 31, 2019 and 2018, the Company held cash, cash equivalents and short-term investments classified as available-for-sale securities as follows:

	December 31, 2019						December 31, 2018
	Amortized Cost			Estimated Fair Value			Amortized Cost			Estimated Fair Value
	(in thousands)
Cash and cash equivalents	$	76,521		$	76,521		$	55,501		$	55,501
Money market funds	1,058			1,058			1,265			1,265
Certificates of deposit	198,561			198,663			95,080			95,038
Government debt securities	232,357			232,604			100,449			100,478
Corporate debt securities	365,792			367,051			186,571			186,208
Total	874,289			875,897			438,866			438,490
Less amounts classified as cash and cash equivalents	(77,579		)	(77,579		)	(56,766		)	(56,766		)
Short-term investments	$	796,710		$	798,318		$	382,100		$	381,724

Schedule of contractual maturities of short-term investments

The contractual maturities of short-term investments at December 31, 2019 and 2018 were as follows:

	December 31, 2019				December 31, 2018
	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value
	(in thousands)
Due in less than one year	$	424,616	$	425,053	$	281,303	$	280,959
Due in one to three years	372,094		373,265		100,797		100,765
	$	796,710	$	798,318	$	382,100	$	381,724