Marketable Securities (Tables)

6 Months Ended

Jun. 30, 2018

Investments, Debt and Equity Securities [Abstract]

Schedule of available-for-sale marketable securities and cash and cash equivalents

Available-for-sale marketable securities and cash and cash equivalents as of June 30, 2018 and December 31, 2017 consist of the following (in thousands):

	June 30, 2018
	Amortized Cost Value		Gross  Unrealized  Gains		Gross  Unrealized  Losses			Fair Value
Cash and cash equivalents:
Cash	$	19,018	$	—	$	—		$	19,018
Money market funds	32,423		—		—			32,423
Total	$	51,441	$	—	$	—		$	51,441
Marketable securities:
Domestic corporate debt securities	$	207,834	$	—	$	(954	)	$	206,880
Agency bonds	59,949		—		(336		)	59,613
Total	$	267,783	$	—	$	(1,290	)	$	266,493

	December 31, 2017
	Amortized Cost Value		Gross  Unrealized  Gains		Gross  Unrealized  Losses			Fair Value
Cash and cash equivalents:
Cash	$	73,302	$	—	$	—		$	73,302
Money market funds	325		—		—			325
Domestic corporate commercial paper	44,937		—		—			44,937
Total	$	118,564	$	—	$	—		$	118,564
Marketable securities:
Domestic corporate debt securities	$	207,320	$	1	$	(235	)	$	207,086
Domestic corporate commercial paper	29,844		—		(7		)	29,837
Agency bonds	74,842		—		(73		)	74,769
Total	$	312,006	$	1	$	(315	)	$	311,692