Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities:
Net loss	$ (15,431)	$ (18,193)
Reconciliation of net loss to net cash used in operating activities
Depreciation	882	1,140
Amortization of intellectual property	179	180
Fair value of common stock issued for consulting services	19	225
Stock-based compensation	2,255	2,201
Fair value of common stock issued for director fees	21	0
Amortization of deferred financing costs	13	0
Inventory NRV adjustment	0	146
Loss (gain) on disposal of property and equipment	(596)	5,665
Forgiveness of PPP loan	0	(332)
Impairment of equipment	579	545
Lease of building	920	553
Changes in operating assets and liabilities
Accounts receivable	120	(237)
Inventory	(155)	822
Prepaid expenses and other current assets	93	345
Accounts payable	22	8
Accrued liabilities	1,428	378
Other assets and liabilities	(497)	(508)
Net cash used in operating activities	(10,148)	(7,062)
Cash flows from investing activities:
Purchases of property and equipment	(4,771)	(2,350)
Proceeds from sale of equipment	1,760	275
Equipment deposits and other assets	91	79
Investment in LINICO	(500)	(232)
Net cash used in investing activities	(3,420)	(2,228)
Cash flows from financing activities:
Proceeds from note payable	5,886	0
Proceeds from exercise of stock options	0	728
Proceeds from ATM, net	6,519	10,166
Proceeds from employee stock purchase plan	108	0
Net cash provided by financing activities	12,513	10,894
Net increase (decrease) in cash and cash equivalents	(1,055)	1,604
Cash and cash equivalents at beginning of period	8,137	6,533
Cash and cash equivalents at end of period	7,082	8,137
Supplemental disclosure of cash flow information:
Cash paid for interest, net of amounts capitalized	21	84
Cash paid for income taxes	2	2
Non-cash financing activities
Fair value of common stock issued to consultants	91	19
Change in property and equipment resulting from change in accounts payable	875	(368)
Change in property and equipment resulting from change in accrued expenses	0	(55)
Change in investing activity resulting from issuance of equity	$ (1,268)	$ 0