Available-for-Sale Securities and Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2019

Available For Sale Securities And Fair Value Measurements [Abstract]

Summary of the classification of available-for-sale securities in condensed consolidated balance sheets

The available-for-sale securities in our Condensed Consolidated Balance Sheets are as follows:

	September 30, 2019		December 31, 2018
	(in thousands)
Cash equivalents	$	30,144	$	27,075
Short-term marketable securities	186,697		165,135
Long-term marketable securities	35,250		—
Total marketable securities	$	252,091	$	192,210

Schedule of available-for-sale securities

The following table presents our available-for-sale securities grouped by asset type:

	Fair Value Hierarchy Level	September 30, 2019									December 31, 2018
		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
		(in thousands)
Corporate bonds	Level 2	$	95,742	$	190	$	(6	)	$	95,926	$	54,513	$	2	$	(46	)	$	54,469
Commercial paper	Level 2	25,230		—		—			25,230		67,906		—		—			67,906
Asset-backed securities	Level 2	44,308		93		—			44,401		10,970		—		(5		)	10,965
Repurchase agreements	Level 2	22,000		—		—			22,000		15,000		—		—			15,000
U.S. treasury securities	Level 1	56,347		49		(6		)	56,390		39,308		—		(21		)	39,287
Money market funds	Level 1	8,144		—		—			8,144		4,583		—		—			4,583
Total Marketable securities		$	251,771	$	332	$	(12	)	$	252,091	$	192,280	$	2	$	(72	)	$	192,210