Condensed Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024
Operating activities:
Net loss	$ (8,215)	$ (13,461)
Adjustments to reconcile net loss to net cash used in operating activities:
Bad debt expense	49	56
Inventory reserve	925	896
Depreciation and amortization	3,170	3,262
Stock-based compensation	1,802	2,140
Deferred taxes	41	(44)
Accrued interest income on short-term investments	54	0
Amortization of discount on short-term investments	(355)	0
Amortization of debt financing costs	129	188
Other adjustment to loan exit fee	(485)	0
Non-cash lease expense	61	94
Loss on disposal of property, plant, and equipment	19	49
Changes in operating assets and liabilities:
Accounts receivable	(877)	(705)
Inventories	(1,734)	(289)
Prepaid expenses and other current assets	(40)	413
Other non-current assets	34	206
Accounts payable	380	(389)
Accrued liabilities	(1,152)	(1,764)
Other	(10)	(48)
Cash used in operating activities	(6,204)	(9,396)
Investing activities:
Purchases of short-term investments	(9,735)	0
Maturities of short-term investments	16,000	0
Proceeds from sale of property, plant, and equipment	0	125
Purchases of property, plant, and equipment	(413)	(227)
Cash provided by investing activities	5,852	(102)
Financing activities:
Proceeds from long-term debt	1,110	0
Payment of exit fee costs	(1,110)	0
Payments related to equity financing	0	(37)
Repayment of financed insurance premiums	(56)	(409)
Proceeds from exercise of stock options	20
Proceeds from issuance of common stock under employee stock purchase plan	56	81
Payment of debt issuance costs	(100)	(25)
Cash used in financing activities	(80)	(390)
Change in cash and cash equivalents	(432)	(9,888)
Cash and cash equivalents at beginning of period	3,708	28,484
Cash and cash equivalents at end of period	3,276	18,596
Supplemental cash flow disclosures:
Income taxes paid	34	0
Interest paid, net of amounts capitalized	722	770
Capitalized property, plant, and equipment included in accounts payable and accrued liabilities	159	99
Issuance of common stock warrants	0	132
Recognition of operating right-of-use lease asset	146	1,293
Recognition of operating lease liabilities	$ 146	$ 1,306