Investments (Tables)

6 Months Ended

Jun. 30, 2014

Investment in Marketable Securities [Abstract]

Investments

(in thousands)	At June 30, 2014
	Cost		Gross Unrealized Losses			Gross Unrealized Gains		Estimated Fair Value
Short-term investments	$	47,661	$	(31	)	$	12	$	47,642
Marketable equity securities	13,972		(677		)	466		13,761

(in thousands)	At December 31, 2013
	Cost		Gross Unrealized Losses			Gross Unrealized Gains		Estimated Fair Value
Marketable equity securities	$	17,649	$	(3,300	)	$	172	$	14,521

Gross unrealized losses on investment securities

The following table summarizes the gross unrealized losses on investment securities for which other-than-temporary impairments have not been recognized and the fair values of those securities, aggregated by the length of time the individual securities have been in a continuous unrealized loss position, at June 30, 2014 (in thousands):

	Less than twelve months					Twelve months or more					Total
	Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value
Short-term investments	$	(31	)	$	29,090	$	—		$	—	$	(31	)	$	29,090
Marketable equity securities	$	—		$	—	$	(677	)	$	1,399	$	(677	)	$	1,399