Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Cash flows from operating activities
Net loss	$ (5,369)	$ (4,917)	$ (15,673)	$ (14,138)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation			457	298
Non-cash lease expense			23	90
Stock-based compensation			7,987	7,906
Accretion and short-term investment discount			(287)
Changes in operating assets and liabilities:
Accounts receivable			(156)	329
Inventories			1,088	(3,280)
Prepaid expenses and other current assets			470	1,071
Other assets			73	45
Accounts payable			270	687
Accrued liabilities			(146)	(19)
Deferred revenue			(798)	1,199
Other liabilities			(8)	(51)
Net cash used in operating activities			(6,700)	(5,863)
Cash flows from investing activities
Purchase of property and equipment			(366)	(2,009)
Proceeds from maturity of short-term investments			20,131
Net cash provided by (used in) investing activities			19,765	(2,009)
Cash flows from financing activities
Proceeds from issuance of stock, net of issuance costs			55	159
Net cash provided by financing activities			55	159
Net increase (decrease) in cash, cash equivalents, and restricted cash			13,120	(7,713)
Cash, cash equivalents, and restricted cash at beginning of period			9,855	40,144
Cash, cash equivalents, and restricted cash at end of period	22,975	32,431	22,975	32,431
Supplemental disclosure of cash flow information:
Purchase of property and equipment included in accounts payable				163
Reconciliation of cash, cash equivalents, and restricted cash to balance sheet as of September 30th:
Cash and cash equivalents	22,100	30,938	22,100	30,938
Restricted cash - current	525	618	525	618
Restricted cash	350	875	350	875
Total cash, cash equivalents, and restricted cash	$ 22,975	$ 32,431	$ 22,975	$ 32,431