INVESTMENTS

The Company invests part of its cash balances in a managed portfolio of liquid investments including highly-rated corporate bonds which are 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 March 31, 2014
	Cost		Gross Unrealized Losses			Gross Unrealized Gains		Estimated Fair Value
Short-term investments	$	45,724	$	(96	)	$	—	$	45,628
Marketable equity securities	15,484		(724		)	886		15,646



	At December 31, 2013
	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 March 31, 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	$	(96	)	$	45,628	$	—		$	—	$	(96	)	$	45,628
Marketable equity securities	$	—		$	—	$	(724	)	$	1,320	$	(724	)	$	1,320

In the three months ended March 31, 2014 and 2013, the Company recognized a net unrealized gain of $0.6 million and a net unrealized loss of $3.6 million, 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 $2.6 million and $35 thousand for the three months ended March 31, 2014 and 2013, respectively.