Marketable Securities (Tables)

3 Months Ended

Mar. 31, 2019

Investments, Debt and Equity Securities [Abstract]

Summary of marketable securities

The following is a summary of our marketable securities as of March 31, 2019 and December 31, 2018 (in thousands):

	March 31, 2019
			Gross		Gross			Estimated
	Amortized		Unrealized		Unrealized			Fair
	Cost		Gains		Losses			Value
Short-term marketable securities:*
Corporate debt securities	$	39,368	$	17	$	(90	)	$	39,295
Certificates of deposit	10,000		—		—			10,000
U.S. treasury and government agency securities	6,391		—		(34		)	6,357
Commercial paper	1,500		—		—			1,500
Total short-term marketable securities	$	57,259	$	17	$	(124	)	$	57,152
Long-term marketable securities:**
Corporate debt securities	$	69,734	$	362	$	(155	)	$	69,941
Certificates of deposit	1,500		—		—			1,500
Total long-term marketable securities	71,234		362		(155		)	71,441
Total marketable securities	$	128,493	$	379	$	(279	)	$	128,593

* Represents marketable securities with a remaining maturity of less than one year.

** Represents marketable securities with a remaining maturity of one to three years classified as short-term on our condensed consolidated balance sheets.

	December 31, 2018
			Gross		Gross			Estimated
	Amortized		Unrealized		Unrealized			Fair
	Cost		Gains		Losses			Value
Short-term marketable securities:*
Corporate debt securities	$	51,184	$	—	$	(236	)	$	50,948
Certificates of deposit	7,647		—		(34		)	7,613
U.S. treasury and government agency securities	3,995		—		—			3,995
Commercial paper	12,000		—		—			12,000
Total short-term marketable securities	$	74,826	$	—	$	(270	)	$	74,556
Long-term marketable securities:**
Corporate debt securities	$	62,530	$	52	$	(433	)	$	62,149
U.S. treasury and government agency securities	2,742		—		(32		)	2,710
Certificates of deposit	1,500		—		—			1,500
Total long-term marketable securities	66,772		52		(465		)	66,359
Total marketable securities	$	141,598	$	52	$	(735	)	$	140,915

* Represents marketable securities with a remaining maturity of less than one year.

** Represents marketable securities with a remaining maturity of one to three years classified as short-term on our condensed consolidated balance sheets.