Cash and Cash Equivalents and Investments

9 Months Ended

Sep. 30, 2015

Cash and Cash Equivalents and Investments [Abstract]

Cash and Cash Equivalents Disclosure

Cash and Cash Equivalents and Investments

The fair value of cash and cash equivalents and investments held at September 30, 2015 and December 31, 2014 are as follows:

	As of September 30, 2015
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(in thousands)
Cash and cash equivalents	$	61,674	$	—	$	—		$	61,674
Securities maturing within one year:
Certificates of deposit	553		—		—			553
U.S. treasury securities	191,231		59		—			191,290
Corporate debt securities	2,906		—		(1		)	2,905
Total short-term investments	$	194,690	$	59	$	(1	)	$	194,748
Total cash and cash equivalents and investments	$	256,364	$	59	$	(1	)	$	256,422
	As of December 31, 2014
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
			(in thousands)
Cash and cash equivalents	$	137,266	$	—	$	—		$	137,266
Securities maturing within one year:
Certificates of deposit	552		—		—			552
U.S. treasury securities	201,584		3		(66		)	201,521
Total short-term investments	$	202,136	$	3	$	(66	)	$	202,073
Total cash and cash equivalents and investments	$	339,402	$	3	$	(66	)	$	339,339

There were no realized gains or losses for the nine months ended September 30, 2015, and no realized gains or losses for the nine months ended September 30, 2014. The cost of securities sold is based on the specific identification method.