Marketable Securities

12 Months Ended

Dec. 31, 2017

Marketable Securities

Marketable Securities

(5) Marketable Securities

        The following is a summary of marketable securities, classified as available-for-sale:

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
	(In thousands)
December 31, 2017
Marketable securities
U.S. government and municipal obligations
Maturing in one year or less	$	26,164	$	3	$	(9	)	$	26,158
Maturing after one year through three years		—		—		—			—
Total U.S. government and municipal obligations	$	26,164	$	3	$	(9	)	$	26,158
Corporate debt securities
Maturing in one year or less	$	73,007	$	1	$	(27	)	$	72,981
Maturing after one year through three years		—		—		—			—
Total corporate debt securities	$	73,007	$	1	$	(27	)	$	72,981
Total marketable securities	$	99,171	$	4	$	(36	)	$	99,139
December 31, 2016
Marketable securities
U.S. government and municipal obligations
Maturing in one year or less	$	52,754	$	5	$	(12	)	$	52,747
Maturing after one year through three years		296		8		—			304
Total U.S. government and municipal obligations	$	53,050	$	13	$	(12	)	$	53,051
Corporate debt securities
Maturing in one year or less	$	94,320	$	—	$	(56	)	$	94,264
Maturing after one year through three years		—		—		—			—
Total corporate debt securities	$	94,320	$	—	$	(56	)	$	94,264
Total marketable securities	$	147,370	$	13	$	(68	)	$	147,315

        The Company holds investment grade marketable securities, and none were considered to be other-than-temporarily impaired as of December 31, 2017. Marketable securities include $0.3 million and $0.6 million in accrued interest at December 31, 2017 and December 31, 2016, respectively.