Investments in Available-for-Sale Securities (Tables)

6 Months Ended

Jun. 30, 2018

Debt Securities, Available-for-sale [Abstract]

Available-for-sale Securities

The Company’s investments in available-for-sale marketable securities are as follows:

	June 30, 2018
										Balance Sheet
										Classification
			Gross Unrealized					Fair		Short-Term		Other
	Cost Basis		Gains		Losses			Value		Investments		Assets
	(In thousands)
Available-for-sale:
U.S. government and agency securities	$	88,858	$	3	$	(161	)	$	88,700	$	88,700	$	—
Corporate notes and bonds	72,516		3		(325		)	72,194		72,194		—
Total Investments	$	161,374	$	6	$	(486	)	$	160,894	$	160,894	$	—

	December 31, 2017
										Balance Sheet
										Classification
			Gross Unrealized					Fair		Short-Term		Other
	Cost Basis		Gains		Losses			Value		Investments		Assets
	(In thousands)
Available-for-sale:
U.S. government and agency securities	$	64,151	$	22	$	(73	)	$	64,100	$	64,100	$	—
Corporate notes and bonds	92,038		—		(292		)	91,746		91,746		—
Total Investments	$	156,189	$	22	$	(365	)	$	155,846	$	155,846	$	—