Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2021

Fair Value Disclosures [Abstract]

Summary of Financial Assets Measured at Fair Value on a Recurring Basis

The following tables summarize the Company’s financial assets measured at fair value on a recurring basis by level within the fair value hierarchy:

	March 31, 2021
	Fair Value Hierarchy	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Market Value
	(In thousands)
Money market funds	Level 1	$	80,312	$	—	$	—		$	80,312
U.S. government treasury securities	Level 1		251,632		409		—			252,041
Total cash equivalents and marketable    securities		$	331,944	$	409	$	—		$	332,353
	December 31, 2020
	Fair Value Hierarchy	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Market Value
	(In thousands)
Money market funds	Level 1	$	37,951	$	—	$	—		$	37,951
U.S. government treasury securities	Level 1		357,725		620		(6	)		358,339
Corporate bonds	Level 2		5,000	$	—	$	—			5,000
Total cash equivalents and marketable    securities		$	400,676	$	620	$	(6	)	$	401,290