Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Cash flows from operating activities
Net loss	$ (4,957)	$ (5,134)	$ (10,304)	$ (9,220)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation			310	194
Non-cash lease expense			16	63
Stock-based compensation			5,314	5,211
Accretion and short-term investment discount			(287)
Changes in operating assets and liabilities:
Accounts receivable			(1,555)	1,658
Inventories			173	(3,353)
Prepaid expenses and other current assets			217	1,365
Other assets			54	60
Accounts payable			(143)	1,037
Accrued liabilities			(386)	(403)
Deferred revenue			866	75
Other liabilities			(8)	(17)
Net cash used in operating activities			(5,733)	(3,330)
Cash flows from investing activities
Purchase of property and equipment			(356)	(1,804)
Proceeds from maturity of short-term investments			20,131
Net cash provided by (used in) investing activities			19,775	(1,804)
Cash flows from financing activities
Proceeds from issuance of stock, net of issuance costs			30	111
Net cash provided by financing activities			30	111
Net increase (decrease) in cash, cash equivalents, and restricted cash			14,072	(5,023)
Cash, cash equivalents, and restricted cash at beginning of period			9,855	40,145
Cash, cash equivalents, and restricted cash at end of period	23,927	35,122	23,927	35,122
Supplemental disclosure of cash flow information:
Purchase of property and equipment included in accounts payable			17	116
Reconciliation of cash, cash equivalents, and restricted cash to balance sheet as of June 30th:
Cash and cash equivalents	22,877	33,498	22,877	33,498
Restricted cash - current	569	618	569	618
Restricted cash	481	1,006	481	1,006
Total cash, cash equivalents, and restricted cash	$ 23,927	$ 35,122	$ 23,927	$ 35,122