Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating activities
Net loss	$ (76,498)	$ (12,885)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,445	692
Stock-based compensation	55,259	4,743
Change in fair value of liabilities	(13,610)	2,477
Warrant expense in connection with Merger	154	0
Lease termination expense	0	1,846
Amortization of debt issuance costs	144	251
Net amortization on securities	1,732	21
Benefit for deferred taxes	(3,178)	0
Non-cash other	871	0
Changes in operating assets and liabilities:
Inventory	(6,928)	(735)
Prepaid expenses and other current assets	2,635	37
Other long-term assets	(58)	777
Accounts payable	6,306	(897)
Accrued liabilities	(794)	1,149
Deferred revenue	217	(65)
Other long-term liabilities	(4)	379
Net cash used in operating activities	(31,307)	(2,210)
Investing activities
Purchases of investments	(219,361)	(84,015)
Maturities of investments	99,375	43,790
Proceeds from sales of investments	3,465	11,550
Acquisition of businesses, net of cash acquired	(46,468)	0
Investment in website development and internal-use software	(3,242)	(1,651)
Purchases of property, equipment, and intangible assets	(279)	(1,293)
Net cash used in investing activities	(166,510)	(31,619)
Financing activities
Proceeds from issuance of redeemable convertible preferred stock	0	51,927
Pre-closing stock repurchase	(22,027)	0
Proceeds from issuance of common stock upon Merger	197,686	0
Proceeds from PIPE	75,000	0
Payments for transaction costs	(12,851)	(2,074)
Proceeds from repayment of promissory notes associated with vested and unvested shares	1,193	0
Proceeds from exercise of Class A common stock warrants, net of redemption payments	787	0
Proceeds from exercise of vested and unvested stock options, net of repurchases and cancelations	567	111
Repayments of principal on term loan	0	(1,515)
Payments for taxes related to net share settlement of equity awards	(5,234)	0
Net cash provided by financing activities	235,121	48,449
Foreign currency effect on cash and cash equivalents	(26)	(11)
Increase in cash, cash equivalents, and restricted cash	37,278	14,609
Cash, cash equivalents, and restricted cash at beginning of period	28,350	22,797
Cash, cash equivalents, and restricted cash at end of period	65,628	37,406
Supplemental disclosures of cash flow information
Cash paid for taxes	279	246
Cash paid for interest	0	10
Non-cash investing and financing activities
Expiration of Class A common stock redemption right	0	4,500
Exercise of convertible preferred stock warrants	0	6,508
Recapitalization of redeemable convertible preferred stock from pre-closing stock repurchase	125	0
Conversion of redeemable convertible preferred stock to common stock	249,837	0
Assumption of Merger warrants liability	51,814	0
Redemption/exercise of Class A common stock warrants	37,834	0
Reclassification of deferred transaction costs	3,929	0
Conversion of Series D preferred stock warrants to Class A common warrants	1,160	0
Deferred transaction costs payable	0	577
Purchase of property and equipment included in accounts payable	0	35
Change in transaction costs payable	568	0
Vesting of early-exercised stock options	147	27
Common stock issued, contingent consideration, and liabilities assumed in acquisition of businesses	99,958	0
Equity awards classified as prepaid expenses	$ 2,625	$ 0