Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash Flows from Operating Activities:
Net loss	$ (16,158)	$ (16,829)	$ (17,855)
Adjustments to reconcile net loss to net cash and cash equivalents used in operating activities:
Depreciation and amortization	400	499	982
Provision for bad debts	(202)	1,328	1,695
Provision for sales returns	0	87	0
Provision for inventory excess and obsolescence	(275)	(591)	413
Inventory disposals and recoveries, net	(122)	1,300	15
Amortization of discount on lines of credit	159	165	140
Amortization of debt issuance costs	356	331	188
Patent litigation mark-to-market	315	0
Change in fair value of warrants	0	(5,850)
Issuance Of Restricted Shares	164	0
Issuance costs for common stock warrants	0	1,641
Stock-based compensation	1,662	3,370	2,742
Gain on debt forgiveness	(3,014)
Warrants issued to consultants	0	0	48
Deferred income taxes	0	0	7
Earned interest income	0	0	2
Changes in operating assets and liabilities:
Accounts receivable	(978)	4,286	655
Inventory	(1,375)	(871)	825
Prepaid expenses and other current assets	285	825	439
Accounts payable and accrued liabilities	1,765	(2,107)	(3,156)
Deferred revenue	308	(379)	114
Net cash and cash equivalents used in operating activities	(16,710)	(12,795)	(12,746)
Cash Flows from Investing Activities:
Purchases of property, plant, and equipment	(707)	(96)	(207)
Net cash and cash equivalents used in investing activities	(707)	(96)	(207)
Cash Flows from Financing Activities:
Proceeds from the issuance of common stock and June 2020 Warrants	14,420	6,912	9,171
Proceeds from the issuance of Series F Convertible Preferred Stock	0	2,700
Proceeds from the issuance of July 2020 Warrants	0	15,300
Payments of equity offering costs	(1,135)	(1,281)	(821)
Payment of July 2020 Warrant issuance costs	0	(1,640)
Borrowings on other long-term loans	0	3,140
Borrowings under term loan	0	0	2,500
Principal payment on term loan	0	(700)
Borrowings on credit facility	0	3,000
Payments of credit facility	0	(3,000)
Payments of debt issuance costs	(25)	(128)	(133)
Proceeds from the exercise of common stock warrants	16,562	46
Proceeds from exercise of stock options	132	0	4
Net cash and cash equivalents provided by financing activities	29,954	24,349	10,721
Effect of exchange rate changes	(238)	317	(23)
Increase (decrease) in cash and cash equivalents	12,299	11,775	(2,255)
Cash, cash equivalents and restricted cash, beginning of year	17,876	6,101	8,356
Cash, cash equivalents and restricted cash, end of year	30,175	17,876	6,101
Supplemental cash flow disclosure:
Cash paid for interest	1,771	1,881	1,784
Cash received for interest	56	11
Cash paid for income taxes	171	22	35
Cash paid for operating leases	246	489	797
Non-cash accrual for capital expenditures	0	0	18
Non-cash settlement of performance award liability	510	151	201
Non-cash right-of-use assets obtained in exchange for lease obligations	48	2,037	276
Equity financing costs in accounts payable	0	74	129
Deemed dividend on preferred stock	546	17,378
Forgiveness of debt	0	10
Receivable from warrants exercised and included in prepaid and other current assets	(1,498)	1,498
Warrants issued in connection with debt instruments	$ 0	$ 67	$ 161