CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Operating activities
Net loss	$ (142,137)	$ (100,243)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Depreciation and amortization	3,255	4,683
Amortization of debt issuance costs	656	269
Stock-based compensation expense	8,930	2,155
Loss on disposal of property and equipment	46	824
Provision for inventory obsolescence	2,917	3,872
Revaluation of preferred stock warrant	20,470	515
Other	1,285	226
Changes in operating assets and liabilities:
Accounts receivable	(4,297)	(15,029)
Inventory	(96,582)	(97,524)
Prepaid expenses and other current assets	(6,639)	(3,168)
Other assets	(2,246)	(2,389)
Accounts payable	10,478	8,769
Accrued expenses	15,679	9,995
Deferred revenue	(24)	2,530
Other liabilities	5,335	4,487
Net cash used in operating activities	(182,874)	(180,028)
Investing activities
Purchase of property and equipment	(5,057)	(2,024)
Net cash used in investing activities	(5,057)	(2,024)
Financing activities
Repayments of long-term debt		(5,835)
Proceeds from vehicle floorplan	842,865	705,281
Repayments of vehicle floorplan	(767,359)	(611,838)
Payment of vehicle floorplan upfront commitment fees	(1,125)
Proceeds from the issuance of redeemable convertible preferred stock, net	21,694
Repurchase of common stock	(1,818)	(542)
Common stock shares withheld to satisfy employee tax withholding obligations	(2,915)
Proceeds from the issuance of common stock in connection with IPO, net of underwriting discount	504,023
Payments of costs related to IPO	(6,791)
Proceeds from the issuance of common stock in connection with follow-on public offering, net of underwriting discount	569,471
Payments of costs related to follow-on public offering	(196)
Proceeds from exercise of stock options	133	365
Other financing activities	(315)	221
Net cash provided by financing activities	1,157,667	87,652
Net (decrease) increase in cash, cash equivalents and restricted cash	969,736	(94,400)
Cash, cash equivalents and restricted cash at the beginning of period	219,587	163,509
Cash, cash equivalents and restricted cash at the end of period	1,189,323	69,109
Supplemental disclosure of cash flow information:
Cash paid for interest	5,340	8,713
Cash paid for income taxes	163	209
Supplemental disclosure of non-cash investing and financing activities:
Accretion of redeemable convertible preferred stock		109,529
Costs related to follow-on public offering included in accrued expenses and accounts payable	1,323
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	$ 55	342
IPO
Supplemental disclosure of non-cash investing and financing activities:
Costs related to IPO included in accrued expenses and accounts payable		$ 113