CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Operating activities
Net loss	$ (142,996)	$ (104,287)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Depreciation and amortization	6,028	2,059
Amortization of debt issuance costs	698	375
Stock-based compensation expense	8,212	4,700
Provision to record inventory at lower of cost or net realizable value	3,093	(1,564)
Revaluation of preferred stock warrant		20,470
Other	2,818	632
Changes in operating assets and liabilities:
Accounts receivable	(41,393)	14,863
Inventory	(99,412)	66,247
Prepaid expenses and other current assets	(26,669)	(7,909)
Other assets	(3,948)	(1,285)
Accounts payable	36,507	919
Accrued expenses	26,306	4,714
Deferred revenue	16,788	(1,835)
Other liabilities	62,117	1,905
Net cash (used in) provided by operating activities	(151,851)	4
Investing activities
Purchase of property and equipment	(8,943)	(3,128)
Acquisition of business, net of cash acquired	(76,145)
Net cash used in investing activities	(85,088)	(3,128)
Financing activities
Proceeds from vehicle floorplan	1,070,110	465,663
Repayments of vehicle floorplan	(1,035,727)	(529,341)
Payment of vehicle floorplan upfront commitment fees		(1,125)
Proceeds from issuance of convertible senior notes	625,000
Issuance costs paid for convertible senior notes	(16,175)
Proceeds from the issuance of redeemable convertible preferred stock, net		21,694
Repurchase of common stock		(1,818)
Common stock shares withheld to satisfy employee tax withholding obligations		(878)
Proceeds from the issuance of common stock in connection with IPO, net of underwriting discount		504,023
Payments of costs related to IPO		(1,740)
Proceeds from exercise of stock options	4,381	13
Other financing activities		(66)
Net cash provided by financing activities	647,589	456,425
Net increase in cash, cash equivalents and restricted cash	410,650	453,301
Cash, cash equivalents and restricted cash at the beginning of period	1,090,039	219,587
Cash, cash equivalents and restricted cash at the end of period	1,500,689	672,888
Supplemental disclosure of cash flow information:
Cash paid for interest	6,713	2,743
Cash paid for income taxes	269
Supplemental disclosure of non-cash investing and financing activities:
Issuance of common stock for acquisition of business	39,030
Fair value of unvested stock options assumed for acquisition of business	1,017
Conversion of redeemable convertible preferred stock warrant to common stock warrant		21,873
Issuance of common stock as upfront payment to nonemployee		2,127
Accrued property and equipment expenditures	$ 420	611
IPO
Supplemental disclosure of non-cash investing and financing activities:
Costs related to IPO included in accrued expenses and accounts payable		$ 5,051