Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
OPERATING ACTIVITIES
Net loss	$ (46,461)	$ (33,045)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	16,440	12,470
Depreciation and amortization	1,776	1,042
Net amortization of premium on available-for-sale securities	439	412
Non-cash operating lease expense	1,004	423
Changes in operating assets and liabilities:
Accounts receivable, net	(846)	(896)
Related party receivables	440	(340)
Other receivables	(632)	(177)
Prepaid expenses and other current assets	(2,176)	(2,601)
Inventory	(3,002)	(2,119)
Other assets	(295)	(16)
Accounts payable	530	(644)
Deferred revenue	53	195
Accrued expenses	(466)	335
Operating lease liabilities	(153)	(187)
Other current liabilities	197
Other noncurrent liabilities	1	(74)
Net cash used in operating activities	(33,151)	(25,222)
INVESTING ACTIVITIES
Purchases of property and equipment	(2,606)	(2,943)
Purchase of available-for-sale securities	(143,651)	(129,320)
Proceeds from maturities of available-for-sale securities	24,000	80,000
Net cash used in investing activities	(122,257)	(52,263)
FINANCING ACTIVITIES
Proceeds from issuance of common stock upon follow-on public offering, net of issuance costs	0	102,959
Proceeds from return of profit	0	11,403
Repurchase of Class A common stock	(20)	(13)
Proceeds from exercise of Class A common stock options including early exercised options	1,218	407
Proceeds from issuance of common stock in connection with employee stock purchase plan	420	0
Net cash provided by financing activities	1,618	114,756
Net increase (decrease) in cash, cash equivalents and restricted cash	(153,790)	37,271
Cash, cash equivalents and restricted cash, beginning of period	233,337	333,928
Cash, cash equivalents and restricted cash, end of period	79,547	371,199
SUPPLEMENTAL DISCLOSURE OF NON-CASH ACTIVITIES
Lease liability obtained in exchange for right-of-use assets	6,855	23,232
Accounts Payable
SUPPLEMENTAL DISCLOSURE OF NON-CASH ACTIVITIES
Property and equipment purchases included in accounts payable and in accrued expenses	8	246
Accrued Liabilities
SUPPLEMENTAL DISCLOSURE OF NON-CASH ACTIVITIES
Property and equipment purchases included in accounts payable and in accrued expenses	$ 1,570	$ 361