Investments in Available-for-Sale Securities (Tables)

12 Months Ended

Dec. 31, 2017

Available-for-sale Securities [Abstract]

Available-for-sale Securities

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

	December 31, 2017
										Balance Sheet
			Gross		Gross					Classification
			Unrealized		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	$	—

	December 31, 2016
										Balance Sheet
			Gross		Gross					Classification
			Unrealized		Unrealized			Fair		Short-Term		Other
	Cost Basis		Gains		Losses			Value		Investments		Assets
	(In thousands)
Available-for-sale:
Corporate notes and bonds	$	88,161	$	—	$	(89	)	$	88,072	$	88,072	$	—
Equity securities	1,749		388		—			2,137		—		2,137
Total Investments	$	89,910	$	388	$	(89	)	$	90,209	$	88,072	$	2,137