Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended		12 Months Ended
	Jun. 30, 2025	Mar. 31, 2025	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (9,270)	$ (8,016)	$ (7,987)	$ (10,219)	$ (17,286)	$ (18,206)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization					75	56
Noncash lease expense relating to operating lease right-of-use assets					103	727
Gain on termination of operating lease, net					(1,612)	0	$ (5,954)
Common stock purchase agreement costs					306	0
Debt issuance costs	36		0		2,020	0
Inventory write-downs, net of scrapped inventory					24	112
Change in fair value of convertible note and warrant liabilities	593		15		(87)	13
Stock-based compensation					3,661	4,754
Amortization of premiums and accretion of discounts on marketable securities, net of change in accrued interest					(157)	(428)
Expected credit losses, net of write-off					2	34
Changes in operating assets and liabilities:
Accounts receivable, net					(18)	90
Inventories, current and noncurrent, net					(114)	89
Prepaid and other current assets					84	724
Other noncurrent assets					134	171
Accounts payable					1,761	108
Accrued expenses and other current liabilities					(1,522)	(1,402)
Operating lease liabilities					(1,532)	(799)
Contract liabilities					0	74
Other noncurrent liabilities					0	(358)
Net cash (used in) operating activities					(14,158)	(14,241)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment					(14)	(234)
Purchases of marketable securities					(14,303)	(15,173)
Proceeds from redemptions and maturities of marketable securities					9,631	18,400
Net cash (used in) provided by investing activities					(4,686)	2,993
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from exercise of stock options					0	134
Proceeds from issuance of convertible note					2,950	146
Payments for convertible note redemptions					(750)	0
Transaction costs related to issuance of convertible note					(608)	0
Proceeds from issuance of common stock under Common Stock Purchase Agreements					10,076	5,560
Stock issuance costs related to Common Stock Purchase Agreements					(404)	(288)
Taxes paid related to the net share settlement of equity awards					(364)	(47)
Proceeds from issuance of common stock through the Employee Stock Purchase Plan					52	26
Net cash provided by financing activities					10,952	5,531
NET DECREASE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH					(7,892)	(5,717)
CASH, CASH EQUIVALENTS AND RESTRICTED CASH—Beginning of period		$ 10,266		$ 19,082	10,266	19,082	19,082
CASH, CASH EQUIVALENTS AND RESTRICTED CASH—End of period	$ 2,374		$ 13,365		2,374	13,365	$ 10,266
SUPPLEMENTAL CASH FLOW INFORMATION:
Cash paid for income taxes, net of refund					21	1
Cash paid for interest					0	0
SUPPLEMENTAL DISCLOSURE OF NONCASH INVESTING AND FINANCING ACTIVITIES:
Noncash debt issuance costs					1,362	0
Stock issuance costs included in accounts payable and accrued liabilities					213	128
Debt issuance costs included in accounts payable and accrued liabilities					50	0
Purchases of property and equipment included in accounts payable and accrued liabilities					$ 5