SHORT-TERM INVESTMENTS

Short-term investments consisted of the following (in thousands):



	December 31, 2014
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Corporate debt securities	$	118,470	$	—	$	(147	)	$	118,323
U.S. government agency securities	24,392		4		(13		)	24,383
Total short-term investments	$	142,862	$	4	$	(160	)	$	142,706



	December 31, 2013
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Corporate debt securities	$	60,882	$	9	$	(13	)	$	60,878

The gross realized gains and gross realized losses related to the Company’s short-term investments were not material for the years ended December 31, 2014 and 2013. The Company did not have short-term investments for the year ended December 31, 2012.

The cost basis and fair value of the short-term investments by contractual maturity consist of the following (in thousands):



	December 31, 2014
	Amortized Cost		Fair Value
One year or less	$	114,231	$	114,113
Over one year and less than two years	28,631		28,593
Total short-term investments	$	142,862	$	142,706

As of December 31, 2013, all of the Company’s investments had a contractual maturity of less than 12 months.

The Company reviews the individual securities in its portfolio to determine whether a decline in a security’s fair value below the amortized cost basis is other-than-temporary. The Company determined that as of December 31, 2014 and 2013 there were no investments in its portfolio that were other-than-temporarily impaired.

Investments in an unrealized loss position consisted of the following (in thousands):



	December 31, 2014					December 31, 2013
	Less Than 12 Months
	Fair Value		Unrealized Loss			Fair Value		Unrealized Loss
Corporate debt securities	$	105,187	$	(147	)	$	18,204	$	(13	)
U.S. government agency securities	15,773		(13		)	—		—
Total short-term investments	$	120,960	$	(160	)	$	18,204	$	(13	)

As of December 31, 2014 and 2013, no investments were in a continuous unrealized loss position for more than twelve months. The Company does not intend to sell any of these investments, and it is not more likely than not, that the Company would be required to sell these investments before recovery of their amortized cost basis, which may be at maturity.