Consolidated Statements Of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash Flows from Operating Activities:
Net loss	$ (10,879)	$ (10,687)
Adjustments to reconcile net loss to net cash and cash equivalents used in operating activities:
Depreciation and amortization	281	527
Provision for bad debts	(162)	1,263
Provision for sales returns	0	87
Inventory write-offs and disposals	(117)	0
Amortization of discounts on lines of credit	126	123
Amortization of debt issuance costs	290	240
Patent litigation mark-to-market	190	0
Change in fair value of warrants	0	(5,850)
Issuance of restricted shares	164	0
Issuance costs for common stock warrants	0	1,640
Stock-based compensation	1,488	2,367
Gain on debt forgiveness	3,014	0
Changes in operating assets and liabilities:
Accounts receivable	(417)	4,017
Inventory	(2,788)	(1,597)
Prepaid expenses and other current assets	235	430
Accounts payable and accrued liabilities	705	(3,445)
Deferred revenue	292	(562)
Net cash and cash equivalents used in operating activities	(13,606)	(11,447)
Cash Flows from Investing Activities:
Purchases of property, plant, and equipment	(396)	(78)
Net cash and cash equivalents used in investing activities	(396)	(78)
Cash Flows from Financing Activities:
Proceeds from the sale of common stock	13,291	6,912
Proceeds from sale of common stock warrants	0	15,300
Proceeds from the issuance of Series F Convertible Preferred Stock	0	2,700
Payments of equity offering costs	(6)	(1,281)
Payment of July 2020 Warrant issuance costs	0	(1,640)
Borrowings on other long-term loans	0	3,140
Principal payment on loan	0	(700)
Borrowings on credit facility	0	3,000
Repayment of credit facility	0	(3,000)
Proceeds from the exercise of common stock warrants	16,560	46
Payment of debt issuance costs	(25)	(75)
Proceeds from exercise of stock options	66	0
Net cash and cash equivalents provided by financing activities	29,886	24,402
Effect of exchange rate changes	(171)	181
Increase in cash, cash equivalents and restricted cash	15,713	13,058
Cash, cash equivalents and restricted cash, beginning of period	17,876	6,101
Cash, cash equivalents and restricted cash, end of period	33,589	19,159
Supplemental cash flow disclosure:
Cash paid for interest	1,328	1,438
Cash received for interest	44	0
Cash paid for income taxes	154	21
Cash paid for operating leases	185	417
Non-cash settlement of liability	510	151
Non-cash right-of-use assets obtained in exchange for lease obligation	48	2,037
Deemed dividend on preferred stock	546	17,378
Warrants issued in connection with debt instruments	$ 0	$ 67