Investments (Tables)

12 Months Ended

Dec. 31, 2016

Investments

Schedule of available-for-sale investments at fair value

	December 31, 2016
			Gross		Gross		Estimated
			Unrealized		Unrealized		Fair
	Cost		(Losses)		Gain		Value
	(In thousands)
Short-term investments – corporate bonds	$	19,740	$	(11)	$	—	$	19,729
Short-term investments – municipal bonds		8,624		(6)		—		8,618
Total short-term investments		28,364		(17)		—		28,347
Total investments	$	28,364	$	(17)	$	—	$	28,347

	December 31, 2015
			Gross		Gross		Estimated
			Unrealized		Unrealized		Fair
	Cost		(Losses)		Gains		Value
	(In thousands)
Short-term investments – commercial paper	$	3,973	$	—	$	1	$	3,974
Short-term investments – corporate bonds		24,600		(25)		—		24,575
Short-term investments – municipal bonds		5,025		—		—		5,025
Total short-term investments		33,598		(25)		1		33,574
Long-term investments – corporate bonds		21,289		(103)		—		21,186
Long-term investments – municipal bonds		5,818		(9)		2		5,811
Total long-term investments		27,107		(112)		2		26,997
Total investments	$	60,705	$	(137)	$	3	$	60,571