Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Cash flows from operating activities
Net loss	$ (5,833)	$ (4,957)	$ (10,340)	$ (10,304)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation			276	310
Non-cash lease expense			6	16
Stock-based compensation			5,127	5,314
Accretion and short-term investment discount				(287)
Changes in operating assets and liabilities:
Accounts receivable			1,040	(1,555)
Inventories			(858)	173
Prepaid expenses and other current assets			(166)	217
Other assets			21	54
Accounts payable			946	(143)
Accrued liabilities			(274)	(386)
Deferred revenue			(1,223)	866
Other liabilities			11	(8)
Net cash used in operating activities			(5,434)	(5,733)
Cash flows from investing activities
Purchase of property and equipment			(22)	(356)
Proceeds from maturity of short-term investments				20,131
Net cash (used in) provided by investing activities			(22)	19,775
Cash flows from financing activities
Proceeds from issuance of stock, net of issuance costs			58	30
Net cash provided by financing activities			58	30
Net (decrease) increase in cash, cash equivalents, and restricted cash			(5,398)	14,072
Cash, cash equivalents, and restricted cash at beginning of period			20,562	9,855
Cash, cash equivalents, and restricted cash at end of period	15,164	23,927	15,164	23,927
Supplemental disclosure of cash flow information:
Purchase of property and equipment included in accounts payable			10	17
Reconciliation of cash, cash equivalents, and restricted cash to balance sheet as of June 30th:
Cash and cash equivalents	14,683	22,877	14,683	22,877
Restricted cash - current	481	569	481	569
Restricted cash		481		481
Total cash, cash equivalents, and restricted cash	$ 15,164	$ 23,927	$ 15,164	$ 23,927