Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
OPERATING ACTIVITIES
Net loss	$ (23,959)	$ (23,646)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	8,724	8,062
Depreciation and amortization	1,249	875
Loss on disposal of property and equipment	226	0
Net amortization of premium on available-for-sale securities	(2,378)	314
Provision for inventory excess and obsolescence	178	0
Non-cash operating lease expense	57	597
Changes in operating assets and liabilities:
Accounts receivable, net	(420)	(298)
Related party receivables	421	157
Other receivables	(166)	(174)
Prepaid expenses and other current assets	(2,282)	(2,850)
Inventory	(40)	300
Other assets	2	11
Accounts payable	(100)	(479)
Deferred revenue	130	18
Accrued expenses	(985)	(2,038)
Other current liabilities	(35)
Other noncurrent liabilities	47	0
Net cash used in operating activities	(19,331)	(19,151)
INVESTING ACTIVITIES
Purchases of property and equipment	(121)	(1,080)
Purchase of available-for-sale securities	(134,520)	0
Proceeds from sale of available-for-sale securities	2,990	0
Proceeds from maturities of available-for-sale securities	146,130	12,000
Net cash provided by investing activities	14,479	10,920
FINANCING ACTIVITIES
Repurchase of Class A common stock	0	(21)
Proceeds from exercise of Class A common stock options	30	773
Net cash provided by financing activities	30	752
Net decrease in cash, cash equivalents and restricted cash	(4,822)	(7,479)
Cash, cash equivalents and restricted cash, beginning of period	53,732	233,337
Cash, cash equivalents and restricted cash, end of period	48,910	225,858
SUPPLEMENTAL DISCLOSURE OF NON-CASH ACTIVITIES
Inventory transferred to property and equipment	771	635
Lease liability obtained in exchange for right-of-use assets	514	6,855
Accounts Payable
SUPPLEMENTAL DISCLOSURE OF NON-CASH ACTIVITIES
Property and equipment purchases included in accounts payable and in accrued expenses	6	204
Accrued Liabilities
SUPPLEMENTAL DISCLOSURE OF NON-CASH ACTIVITIES
Property and equipment purchases included in accounts payable and in accrued expenses	$ 198	$ 183