Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 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

The carrying amounts of certain financial instruments such as cash and cash equivalents, accounts receivable, prepaid expenses, other current assets, accounts payable, accrued expenses and other current liabilities as of December 31, 2021 and 2020 approximate their related fair values due to the short-term maturities of these instruments.

	As of December 31, 2021
	Level 1		Level 2		Level 3		Total
Assets:
Money market securities	$	21,390	$	—	$	—	$	21,390
Government securities		—		134,971		—		134,971
Total assets at fair value	$	21,390	$	134,971	$	—	$	156,361

	As of December 31, 2020
	Level 1		Level 2		Level 3			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):

	Year ended December 31,
	2021			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