Redeemable Convertible Preferred Stock and Preferred Stock Warrants, and Stockholders’ Equity (Deficit) - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended						2 Months Ended	12 Months Ended
	Apr. 19, 2021	Mar. 31, 2021	Feb. 28, 2021	Nov. 30, 2020	Sep. 30, 2020	Aug. 31, 2020	Jul. 31, 2020	Jan. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Preferred Units [Line Items]
Proceeds from issuance of warrants									$ 0	$ 11,943	$ 0
Warrants liability						$ 42,300	$ 2,000		0	42,452	0
Proceeds from exercise of warrants for redeemable convertible preferred stock									183,007	2,500	$ 0
Accretion of redeemable convertible preferred shares to redemption value									$ 4,135	$ 20,959
Excess warrants proceeds paid as compensation						$ 32,300
Redeemable convertible preferred stock, shares outstanding (in shares)	120,534,419								0	102,074,703
Redeemable convertible preferred stock, shares issued (in shares)	120,534,419								0	102,074,703
Initial Public Offering
Preferred Units [Line Items]
Number of redeemable convertible preferred stock converted (in shares)	120,534,419
Series D-1 Convertible Preferred Shares
Preferred Units [Line Items]
Issuance of redeemable convertible preferred stock, net of issuance costs (in shares)				308,182	1,232,370	1,232,730	621,447			1,854,177	6,471,833
Shares issued price per share (in usd per share)				$ 8.11		$ 8.11	$ 8.11
Proceeds from issuance of warrants				$ 2,500		$ 10,000	$ 5,000
Accretion of redeemable convertible preferred shares to redemption value											$ 201
Redeemable convertible preferred stock, shares outstanding (in shares)	20,345,131
Redeemable convertible preferred stock, shares issued (in shares)	20,345,131
Series E Convertible Preferred Stock
Preferred Units [Line Items]
Issuance of redeemable convertible preferred stock, net of issuance costs (in shares)								25,695,018		21,044,019
Shares issued price per share (in usd per share)				$ 14.14
Proceeds from issuance of warrants								$ 363,300
Stock issuance costs								13,100
Redeemable convertible preferred stock, shares outstanding (in shares)	35,172,091
Redeemable convertible preferred stock, shares issued (in shares)	35,172,091
Series E Convertible Preferred Stock | Accumulated Deficit
Preferred Units [Line Items]
Accretion of redeemable convertible preferred shares to redemption value								9,000
Series E Convertible Preferred Stock | Additional Paid-in Capital
Preferred Units [Line Items]
Accretion of redeemable convertible preferred shares to redemption value							$ 2,000	$ 4,100
Series E Convertible Preferred Stock | Navistar, Inc.
Preferred Units [Line Items]
Warrants to purchase preferred stock (in shares)		9,477,073
Exercise price per share (in dollars per share)		$ 14.14
Proceeds from exercise of warrants for redeemable convertible preferred stock		$ 134,000
Series E-2 Convertible Preferred Stock
Preferred Units [Line Items]
Redeemable convertible preferred stock, shares outstanding (in shares)	4,331,644
Redeemable convertible preferred stock, shares issued (in shares)	4,331,644
Series E-2 Convertible Preferred Stock | Traton
Preferred Units [Line Items]
Warrants to purchase preferred stock (in shares)			4,331,644
Exercise price per share (in dollars per share)			$ 11.31
Proceeds from exercise of warrants for redeemable convertible preferred stock			$ 49,000