MARKETABLE SECURITIES

12 Months Ended

Dec. 31, 2019

Marketable Securities [Abstract]

Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]

MARKETABLE SECURITIES:

Amortized cost and estimated fair market value of marketable securities classified as available-for-sale (excluding cash equivalents) at December 31, 2019, were as follows:

	Amortized		Gross Unrealized					Estimated Fair
(in thousands)	Cost		Gains		Losses			Market Value
Investments due in 3 months or less:
Corporate securities	$	15,934	$	18	$	—		$	15,952
Total	15,934		18		—			15,952
Investments due in 4-12 months:
Corporate securities	71,223		269		—			71,492
Total	71,223		269		—			71,492
Investments due in 12 months or greater:
Corporate securities	144,658		302		(6		)	144,954
Total	144,658		302		(6		)	144,954
Total marketable securities	$	231,815	$	589	$	(6	)	$	232,398

Amortized cost and estimated fair market value of marketable securities classified as available-for-sale (excluding cash equivalents) at December 31, 2018, were as follows:

	Amortized		Gross Unrealized					Estimated Fair
(in thousands)	Cost		Gains		Losses			Market Value
Investments due in 3 months or less:
Corporate securities	$	6,788	$	—	$	(2	)	$	6,786
Total	6,788		—		(2		)	6,786
Investments due in 4-12 months:
Corporate securities	60,123		—		(244		)	59,879
Total	60,123		—		(244		)	59,879
Investments due in 12 months or greater:
Corporate securities	27,806		2		(22		)	27,786
Total	27,806		2		(22		)	27,786
Total marketable securities	$	94,717	$	2	$	(268	)	$	94,451

The weighted average interest rate of investments at December 31, 2019 and 2018, was approximately 2.17% and 2.65%, respectively. As of December 31, 2019 and 2018, there were no individual securities that had been in a continuous loss position for 12 months or greater.