Investments in Available-for-Sale Securities (Tables)

9 Months Ended

Sep. 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:

	September 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	$	99,754	$	1	$	(180	)	$	99,575	$	99,575	$	—
Corporate notes and bonds	63,155		—		(200		)	62,955		62,955		—
Total Investments	$	162,909	$	1	$	(380	)	$	162,530	$	162,530	$	—

	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	$	—