Cash and Cash Equivalents and Investments

6 Months Ended

Jun. 30, 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 June 30, 2017 and December 31, 2016 are as follows:

	As of June 30, 2017
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(in thousands)
Cash and cash equivalents	$	30,706	$	—	$	—		$	30,706
Securities maturing within one year:
U.S. treasury securities	161,020		—		(178		)	160,842
Corporate debt securities	39,675		—		(36		)	39,639
Total short-term investments	$	200,695	$	—	$	(214	)	$	200,481
Total cash and cash equivalents and investments	$	231,401	$	—	$	(214	)	$	231,187
	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 six months ended June 30, 2017, and no realized gains or losses for the six months ended June 30, 2016. The cost of securities sold is based on the specific identification method.