CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (42,296)	$ (51,348)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	666	463
Gain on sale of property and equipment, net	(52)	0
Noncash lease expense relating to operating lease right-of-use assets	706	654
Impairment of right-of-use assets	47	0
Inventory write-downs, net of scrapped inventory	544	335
Change in fair value of convertible note and warrant liabilities	926	(109)
Stock-based compensation	10,623	11,897
Amortization of premiums and accretion of discounts on marketable securities, net of change in accrued interest	(65)	826
Changes in operating assets and liabilities:
Accounts receivable, net	327	4,033
Inventories, current and noncurrent, net	(2,502)	(1,316)
Prepaid and other current assets	2,884	900
Other noncurrent assets	(2,164)	411
Accounts payable	282	932
Accrued expenses and other current liabilities	(785)	1,354
Operating lease liabilities	(749)	(859)
Contract liabilities	(837)	(1,285)
Net cash used in operating activities	(32,445)	(33,112)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of property and equipment	(808)	(1,759)
Proceeds from sale of property and equipment	96	0
Proceeds from redemptions and maturities of marketable securities	35,850	26,234
Net cash provided by investing activities	35,138	24,475
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from exercise of stock options	391	668
Taxes paid related to the net share settlement of equity awards	(1,051)	(3,400)
Payments for convertible note redemptions	(4,973)	0
Proceeds from issuance of common stock under the Common Stock Purchase Agreement	0	1,422
Proceeds from issuance of common stock through Employee Stock Purchase Plan	118	0
Net cash used in financing activities	(5,515)	(1,310)
NET INCREASE (DECREASE) IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	(2,822)	(9,947)
CASH, CASH EQUIVALENTS AND RESTRICTED CASH—Beginning of period	21,214	16,333
CASH, CASH EQUIVALENTS AND RESTRICTED CASH—End of period	18,392	6,386
SUPPLEMENTAL CASH FLOW INFORMATION:
Cash paid for income taxes	10	10
Cash paid for interest	106	0
SUPPLEMENTAL DISCLOSURE OF NONCASH INVESTING AND FINANCING ACTIVITIES:
Purchases of property and equipment included in accounts payable and accrued liabilities	48	562
Operating lease right-of-use assets obtained in exchange for lease obligations upon adoption of ASC 842 / Operating lease right-of-use assets obtained in exchange for lease obligation	0	556
Conversion of convertible notes and accrued interest into Class A common stock	3,009	0
Taxes related to net share settlement of equity awards included in accrued liabilities	1	15
Cumulative Effect, Period of Adoption, Adjustment
SUPPLEMENTAL DISCLOSURE OF NONCASH INVESTING AND FINANCING ACTIVITIES:
Operating lease right-of-use assets obtained in exchange for lease obligations upon adoption of ASC 842 / Operating lease right-of-use assets obtained in exchange for lease obligation	$ 0	$ 16,284