INVESTMENTS

The Company invests part of its cash balances in a managed portfolio of liquid investments, including highly-rated corporate bonds, classified as short-term investments. The Company also invests in marketable equity securities of silver and gold exploration and development companies. These investments are classified as available-for-sale and are measured at fair value in the financial statements with unrealized gains and losses recorded in Other comprehensive income (loss).



	At September 30, 2014
In thousands	Cost		Gross Unrealized Losses			Gross Unrealized Gains		Estimated Fair Value
Short-term investments	$	49,559	$	(44	)	$	5	$	49,520
Marketable equity securities	9,678		(786		)	270		9,162



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

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 September 30, 2014:



	Less than twelve months					Twelve months or more					Total
In thousands	Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value
Short-term investments	$	(44	)	$	33,125	$	—		$	—	$	(44	)	$	33,125
Marketable equity securities	$	(107	)	$	1,904	$	(679	)	$	1,365	$	(786	)	$	3,269

The Company recognized net of tax unrealized losses of $1.1 million and unrealized gains of $0.3 million in the three months ended September 30, 2014 and 2013, respectively, and net of tax unrealized losses of $1.5 million and $10.8 million in the nine months ended September 30, 2014 and 2013, respectively, in Other comprehensive income (loss). The Company performs a quarterly assessment on each of its marketable securities with unrealized losses to determine if the security is other than temporarily impaired. The Company recorded other-than-temporary impairment losses of $1.1 million and $0.9 million in the three months ended September 30, 2014 and 2013, respectively, and $4.6 million and $18.1 million in the nine months ended September 30, 2014 and 2013, respectively.