Fair Value Measurements and Fair Value of Financial Instruments (Tables)

6 Months Ended

Jun. 30, 2021

Fair Value Disclosures [Abstract]

Schedule of Marketable Securities Classified as Available-for-sale Securities

Marketable securities, all of which are classified as available-for-sale securities, consisted of the following at June 30, 2021 and December 31, 2020 (in thousands):

	June 30, 2021
	Amortized		Unrealized		Unrealized			Estimated
	Cost		Gains		Losses			Fair Value
Asset-backed securities	$	38,644	$	3	$	(6	)	$	38,641
U.S. treasury securities		29,993		—		(12	)		29,981
Other government agency securities		5,098		—		(5	)		5,093
Commercial paper		90,819		—		—			90,819
Corporate debt securities		88,092		16		(18	)		88,090
Total	$	252,646	$	19	$	(41	)	$	252,624

	December 31, 2020
	Amortized		Unrealized		Unrealized			Estimated
	Cost		Gains		Losses			Fair Value
Asset-backed securities	$	2,639	$	—	$	—		$	2,639
U.S. treasury securities		1,300		—		—			1,300
Commercial paper		6,795		—		—			6,795
Corporate debt securities		6,562		1		(1	)		6,562
Total	$	17,296	$	1	$	(1	)	$	17,296

Schedule of Fair Values of Assets and Liabilities Measured at Fair Value on Recurring Basis

At June 30, 2021 and December 31, 2020, the fair values of the Company’s assets and liabilities, which are measured at fair value on a recurring basis, were determined using the following inputs (in thousands):

	June 30, 2021
	Total		(Level 1)		(Level 2)		(Level 3)
Money market funds	$	54,700	$	54,700	$	—	$	—
Asset-backed securities		38,641		—		38,641		—
U.S. treasury securities		29,981		—		29,981		—
Other government agency securities		5,093		—		5,093		—
Commercial paper		90,819		—		90,819		—
Corporate debt securities		88,090		—		88,090		—
Total	$	307,324	$	54,700	$	252,624	$	—

	December 31, 2020
	Total		(Level 1)		(Level 2)		(Level 3)
Money market funds	$	3,921	$	3,921	$	—	$	—
Asset-backed securities		2,640		—		2,640		—
U.S. treasury securities		1,300		1,300		—		—
Commercial paper		6,795		—		6,795		—
Corporate debt securities		6,561		—		6,561		—
Total	$	21,217	$	5,221	$	15,996	$	—
Liabilities:
Preferred stock purchase rights liability	$	25,224	$	—	$	—	$	25,224

Schedule of Changes in Estimated Fair Value of Financial Instruments

The following table provides a summary of changes in the estimated fair value of the financial instruments using significant Level 3 inputs (in thousands):

	Series C Convertible Preferred Stock Purchase Right Liability
Balance at December 31, 2020	$	25,224
Change in fair value		6,084
Reclassification to equity		(31,308	)
Balance at June 30, 2021	$	—