Fair Value of Financial Assets and Liabilities (Tables)

6 Months Ended

Jun. 30, 2017

Fair Value of Financial Assets and Liabilities

Schedule of assets and liabilities measured at fair value on a recurring basis

	June 30, 2017
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents	$	23,596	$	6,993	$	—	$	30,589
Marketable securities		—		137,789		—		137,789
Total	$	23,596	$	144,782	$	—	$	168,378

	December 31, 2016
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents	$	11,522	$	12,691	$	—	$	24,213
Marketable securities		—		143,963		—		143,963
Total	$	11,522	$	156,654	$	—	$	168,176

Schedule of the fair value of available for sale marketable securities by type of security

	June 30, 2017
			Gross		Gross
	Amortized		Unrealized		Unrealized		Fair
	Cost		Gain		Loss		Value
Marketable securities:
Corporate debt securities	$	38,318	$	—	$	(25)	$	38,293
Commercial paper		34,098		—		—		34,098
Asset-backed securities		25,938		—		(21)		25,917
U.S. government agency debt securities		39,539		—		(58)		39,481
Total marketable securities	$	137,893	$	—	$	(104)	$	137,789

	December 31, 2016
			Gross		Gross
	Amortized		Unrealized		Unrealized		Fair
	Cost		Gain		Loss		Value
Marketable securities:
Corporate debt securities	$	51,352	$	—	$	(59)	$	51,293
Commercial paper		20,463		—		—		20,463
Asset-backed securities		28,692		6		(1)		28,697
U.S. government agency debt securities		43,505		8		(3)		43,510
Total marketable securities	$	144,012	$	14	$	(63)	$	143,963