Cash and Cash Equivalents and Investments

3 Months Ended

Mar. 31, 2017

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 March 31, 2017 and December 31, 2016 are as follows:

	As of March 31, 2017
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(in thousands)
Cash and cash equivalents	$	2,455	$	—	$	—		$	2,455
Securities maturing within one year:
U.S. treasury securities	191,443		—		(195		)	191,248
Corporate debt securities	66,109		—		(69		)	66,040
Total short-term investments	$	257,552	$	—	$	(264	)	$	257,288
Total cash and cash equivalents and investments	$	260,007	$	—	$	(264	)	$	259,743
	As of December 31, 2016
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
			(in thousands)
Cash and cash equivalents	$	46,600	$	—	$	—		$	46,600
Securities maturing within one year:
U.S. treasury securities	227,911		1		(107		)	227,805
Corporate debt securities	72,188		1		(90		)	72,099
Total short-term investments	$	300,099	$	2	$	(197	)	$	299,904
Total cash and cash equivalents and investments	$	346,699	$	2	$	(197	)	$	346,504

There were $7,000 in realized losses for the three months ended March 31, 2017, and no realized gains or losses for the three months ended March 31, 2016. The cost of securities sold is based on the specific identification method.