Investments (Tables)

12 Months Ended

Dec. 31, 2017

Available For Sale Securities Current [Abstract]

Schedule of changes in accumulated other comprehensive (loss) income

The changes in AOCI associated with the net unrealized holding losses on available-for-sale investments during the year ended 2016 were as follows (in thousands):

(In thousands)	Net Unrealized Gains (Losses) on Marketable Securities
Balance at December 31, 2015	$	(119	)
Other comprehensive loss before reclassifications:		—
Amounts reclassified from accumulated other    comprehensive loss		119
Net current period other comprehensive loss		119
Balance at December 31, 2016		—