Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Statement of Cash Flows [Abstract]
Net loss	$ (25,703)	$ (2,212)
Cash Flows from Financing Activities
Payments made on long-term debt	(51)	(7)
Advance from holder of marketable securities	4,722	0
Repayment of advance from marketable securities	(4,722)	0
PIPE issuance	125,000	0
Merger financing	309,999	0
Payment made on accrued dividends	(4,853)	0
Payments to existing shareholders of Former CarLotz	(62,693)	0
Transaction costs and advisory fees	(47,579)	0
Payments made on cash considerations associated with stock options	(2,465)	0
Repayment of Paycheck Protection Program loan	(1,749)	0
Payments made on note payable	(3,000)	0
Borrowings on long-term debt	0	2,249
Payments on floor plan notes payable	(109,034)	(16,877)
Borrowings on floor plan notes payable	127,279	16,834
Net Cash Provided by Financing Activities	330,854	2,199
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation and amortization expense	1,623	148
Amortization and accretion - marketable securities	1,712	0
Depreciation – lease vehicles	69	121
Loss on marketable securities	0	(13)
Provision for doubtful accounts	85	5
Stock-based compensation expense	49,114	37
Change in fair value of Merger warrants liability	(24,794)	0
Change in fair value of historic warrants liability	0	(30)
Change in fair value of earnout shares	(56,621)	0
Change in fair value of debt issuance costs and stock warrant	0	18
Change in fair value of redeemable convertible preferred stock tranche obligation	0	(962)
Unpaid interest expense on capital lease obligations	199	0
Change in Operating Assets and Liabilities:
Accounts receivable	(4,786)	290
Inventories	(46,774)	(602)
Other current assets	(8,414)	(247)
Other assets	(4,267)	28
Accounts payable	3,541	893
Accrued expenses	5,441	771
Accrued expenses – related party	(229)	75
Other current liabilities	382	(115)
Other liabilities	(753)	756
Net Cash Used in Operating Activities	(110,175)	(1,039)
Cash Flows from Investing Activities
Purchase of property and equipment	(6,766)	(37)
Capitalized website and internal-use software costs	(11,511)	0
Purchase of marketable securities	(359,381)	(999)
Proceeds from sales of marketable securities	212,823	53
Purchase of lease vehicles	(939)	(76)
Net Cash Used in Investing Activities	(165,774)	(1,059)
Net Change in Cash and Cash Equivalents Including Restricted Cash	54,905	101
Cash and cash equivalents and restricted cash, beginning	2,813	4,102
Cash and cash equivalents and restricted cash, ending	57,718	4,203
Supplemental Disclosure of Cash Flow Information
Cash paid for interest	1,000	248
Supplementary Schedule of Non-cash Investing and Financing Activities:
Transfer from lease vehicles to inventory	166	199
Redeemable convertible preferred stock distributions accrued	0	1,399
Issuance of common stock warrants	0	15
KAR/AFC exercise of stock warrants	(144)	0
KAR/AFC conversion of notes payable	(3,625)	0
Convertible redeemable preferred stock tranche obligation expiration	(2,832)	0
Capitalized website and internal use software costs accrued	(1,898)	0
Purchases of property under capital lease obligation	$ (7,651)	$ 0