Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2021

Fair Value Disclosures [Abstract]

Schedule of assets and liabilities measured at fair value on recurring basis and the fair value hierarchy of the valuation techniques

	As of September 30, 2021
	Level I		Level II		Level III		Total
Assets:
Money market securities	$	65,368	$	—	$	—	$	65,368
Government securities		—		99,985		—		99,985
Total assets at fair value	$	65,368	$	99,985	$	—	$	165,353

	As of December 31, 2020
	Level I		Level II		Level III			Total
Assets:
Money market securities	$	11,822	$	—	$	—		$	11,822
Government securities		—		54,981		—			54,981
Total assets at fair value	$	11,822	$	54,981	$	—		$	66,803
Liabilities:
Common stock warrant liability	$	—	$	—	$	(5,018	)	$	(5,018	)
Redeemable convertible preferred stock warrant    liability		—		—		(3,828	)		(3,828	)
Total liabilities at fair value	$	—	$	—	$	(8,846	)	$	(8,846	)

Schedule of estimated fair value for the warrant liabilities measured using significant unobservable inputs

The following table sets forth changes in the estimated fair values for the Company’s warrant liabilities measured using significant unobservable inputs (in thousands):

	Nine Months Ended			Year Ended
	September 30, 2021			December 31, 2020
Beginning of period	$	8,846		$	71,881
Exercise of preferred stock warrants		(1,111	)		(24	)
Expiration of common stock warrant		(5,018	)		—
Change in fair value of common stock warrant		—			(64,628	)
Change in fair value of preferred stock warrants		(2,717	)		1,617
End of period	$	—		$	8,846