Marketable Securities

12 Months Ended

Dec. 31, 2013

Investments Debt And Equity Securities [Abstract]

Marketable Securities

3. Marketable Securities

Available-for-sale securities, all of which have maturities of twelve months or less, as of December 31, 2013 consisted of the following:

	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
	(in thousands)
December 31, 2013:
Commercial paper	$	49,685	$	—	$	(5	)	$	49,680
Corporate debt securities		40,455		—		(19	)		40,436
Total	$	90,140	$	—	$	(24	)	$	90,116

The aggregate fair value of securities held by the Company in an unrealized loss position for less than 12 months as of December 31, 2013 was $77.1 million, representing 21 securities. To determine whether an other-than-temporary impairment exists, the Company performs an analysis to assess whether it intends to sell, or whether it would more likely than not be required to sell, the security before the expected recovery of the amortized cost basis. Where the Company intends to sell a security, or may be required to do so, the security’s decline in fair value is deemed to be other-than-temporary and the full amount of the unrealized loss is recognized on the statement of comprehensive loss as an other-than-temporary impairment charge. When this is not the case, the Company performs additional analysis on all securities with unrealized losses to evaluate losses associated with the creditworthiness of the security. Credit losses are identified where the Company does not expect to receive cash flows, based on using a single best estimate, sufficient to recover the amortized cost basis of a security and amount of the loss recognized in other income (expense).

Available-for-sale securities in an unrealized loss position as of December 31, 2013 consisted of the following:

	Aggregate Fair Value		Unrealized Losses
	(in thousands)
December 31, 2013:
Commercial paper	$	36,683	$	(5	)
Corporate debt securities		40,436		(19	)
	$	77,119	$	(24	)

The Company does not intend to sell and it is not more likely than not that the Company will be required to sell the above investments before recovery of their amortized cost bases, which may be maturity. The Company determined that there was no material change in the credit risk of the above investments. As a result, the Company determined it did not hold any investments with an other-than-temporary-impairment as of December 31, 2013.