Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended				6 Months Ended		12 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Operating Activities:
Net loss	$ (7,725)	$ (4,330)	$ (4,845)	$ (6,485)	$ (12,055)	$ (11,330)
Adjustments to reconcile net loss to cash flows used in operating activities:
Depreciation and amortization					151	169
Stock-based compensation expense					273	378
Change in fair value of warrant liability	(198)		0		(720)	755
Warrant financing costs	5,607		0		5,607	0
Net realized gain on marketable securities					0	(65)
Changes in operating assets and liabilities:
Accounts receivable					659	230
Inventory, net					30	(72)
Other current assets					(395)	(547)
Other assets and liabilities					5	(20)
Accounts payable and accrued expenses					829	(856)
Net cash used in operating activities					(5,616)	(11,358)
Investing Activities:
Proceeds from sale of marketable securities					0	578
Additions to intangible assets					0	(99)
Purchases of property and equipment					(53)	(64)
Net cash provided by (used in) investing activities					(53)	415
Financing Activities:
Issuance of common stock from offering					2,403	0
Proceeds from the exercise of Series J Convertible Preferred Warrants					500	0
Proceeds from ATM stock offerings, net					0	2,108
Net cash provided by financing activities					2,903	2,108
Effect of exchange rate changes on cash					(11)	(6)
Net decrease in cash and cash equivalents					(2,777)	(8,841)
Cash and cash equivalents - beginning of period		$ 3,800		$ 17,737	3,800	17,737	$ 17,737
Cash and cash equivalents - end of period	1,023		8,896		1,023	8,896	$ 3,800
Supplemental cash flow information
Issuance of Series J Preferred Stock for exercise of Warrants					1,857	0
Issuance of Common Stock for conversion of Series J Preferred Stock					1,535	0
Deemed dividend on Series J Preferred Stock	$ 0		$ 0		(541)	0
Common stock offering costs included in prepaids					$ 306	$ 0