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

3 Months Ended

Mar. 31, 2021

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:

	March 31, 2021		December 31, 2020
	(in thousands)
Cash equivalents	$	30,540	$	50,524
Short-term marketable securities	320,578		364,506
Long-term marketable securities	81,834		36,196
Total marketable securities	$	432,952	$	451,226

Schedule of available-for-sale securities

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

	Fair Value Hierarchy Level	March 31, 2021								December 31, 2020
		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	$	100,413	$	19	$	(37)	$	100,395	$	96,999	$	74	$	(9)	$	97,064
Commercial paper	Level 2	124,870		—		—		124,870		139,791		—		—		139,791
Asset-backed securities	Level 2	49,624		3		(15)		49,612		39,243		15		(1)		39,257
U.S. treasury securities	Level 1	127,490		46		(1)		127,535		124,461		131		(2)		124,590
Money market funds	Level 1	30,540		—		—		30,540		50,524		—		—		50,524
Total marketable securities		$	432,937	$	68	$	(53)	$	432,952	$	451,018	$	220	$	(12)	$	451,226