Available-for-Sale Securities and Fair Value Measurements

12 Months Ended

Dec. 31, 2019

Available For Sale Securities And Fair Value Measurements [Abstract]

Available-for-sale securities and fair value measurements

Available for Sale Securities and Fair Value Measurements

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

	Year Ended December 31,
	2019		2018
	(in thousands)
Cash equivalents	$	18,461	$	27,075
Short-term marketable securities	244,693		165,135
Long-term marketable securities	39,352		—
Total marketable securities	$	302,506	$	192,210

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

	Fair Value Hierarchy Level	December 31, 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	$	109,780	$	136	$	(6	)	$	109,910	$	54,513	$	2	$	(46	)	$	54,469
Commercial paper	Level 2	41,237		—		—			41,237		67,906		—		—			67,906
Asset-backed securities	Level 2	57,195		63		(5		)	57,253		10,970		—		(5		)	10,965
Repurchase agreements	Level 2	18,000		—		—			18,000		15,000		—		—			15,000
U.S. treasury securities	Level 1	75,574		71		—			75,645		39,308		—		(21		)	39,287
Money market funds	Level 1	461		—		—			461		4,583		—		—			4,583
Total Marketable securities		$	302,247	$	270	$	(11	)	$	302,506	$	192,280	$	2	$	(72	)	$	192,210

We estimate the fair value of marketable securities classified as Level 1 using quoted market prices for these or similar investments obtained from a commercial pricing service. We estimate the fair value of marketable securities classified as Level 2 using inputs that may include benchmark yields, reported trades, broker/dealer quotes and issuer spreads.

We do not intend to sell the investments that are currently in an unrealized loss position, and it is highly unlikely that we will be required to sell the investments before recovery of their amortized cost basis, which may be maturity.

As of December 31, 2019, all our marketable securities had original maturities of less than two years. The weighted-average maturity of our holdings was six months. As of December 31, 2019, our long-term marketable securities had remaining maturities ranging from 12 to 17 months. None of our marketable securities changed from one fair value hierarchy to another during the year ended December 31, 2019.