Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash Flows from Operating Activities:
Net loss	$ (16,829)	$ (17,855)	$ (21,516)
Adjustments to reconcile net loss to net cash and cash equivalents used in operating activities:
Depreciation and amortization	499	982	945
Loss on disposal of assets, net			1,228
Provision for bad debts	1,328	1,695	469
Provision for sales returns	87
Provision for inventory excess and obsolescence	(591)	413	166
Inventory write-offs and disposals	1,300	15	128
Amortization of discount on lines of credit	165	140	202
Amortization of debt issuance costs	331	188	126
Change in fair value of warrants	(5,850)
Issuance costs for common stock warrants	1,641
Loss on patent litigation settlement			1,500
Stock-based compensation	3,370	2,742	2,768
Warrants issued to consultants		48
Deferred income taxes		7	(27)
Earned interest income		2	1
Changes in operating assets and liabilities:
Accounts receivable	4,286	655	(1,458)
Inventory	(871)	825	(255)
Prepaid expenses and other current assets	825	439	(25)
Accounts payable and accrued liabilities	(2,107)	(3,156)	1,762
Deferred revenue	(379)	114	(161)
Net cash and cash equivalents used in operating activities	(12,795)	(12,746)	(14,147)
Cash Flows from Investing Activities:
Purchases of property, plant, and equipment	(96)	(207)	(558)
Proceeds from disposal of property, plant, and equipment			36
Net cash and cash equivalents used in investing activities	(96)	(207)	(522)
Cash Flows from Financing Activities:
Proceeds from the issuance of common stock and June 2020 Warrants	6,912	9,171
Proceeds from the issuance of Series F Convertible Preferred Stock	2,700
Proceeds from the issuance of July 2020 Warrants	15,300
Payments of equity offering costs	(1,281)	(821)	(164)
Payment of July 2020 Warrant issuance costs	(1,640)
Principal payments under capital lease obligation			(46)
Borrowings on other long-term loans	3,140
Borrowings under term loan		2,500	12,500
Principal payment on term loan	(700)
Borrowings on credit facility	3,000		3,696
Payments of credit facility	(3,000)		(3,696)
Payments of debt issuance costs	(128)	(133)	(1,058)
Proceeds from the exercise of common stock warrants	46
Proceeds from exercise of stock options		4	3
Net cash and cash equivalents provided by financing activities	24,349	10,721	11,235
Effect of exchange rate changes	317	(23)	(106)
Increase (decrease) in cash and cash equivalents	11,775	(2,255)	(3,540)
Cash, cash equivalents and restricted cash, beginning of year	6,101	8,356	11,896
Cash, cash equivalents and restricted cash, end of year	17,876	6,101	8,356
Supplemental cash flow disclosure:
Cash paid for interest	1,881	1,784	23
Cash received for interest	11
Cash paid for income taxes	22	35	44
Cash paid for operating leases	489	797
Non-cash accrual for capital expenditures		18	31
Non-cash settlement of performance award liability	151	201
Non-cash right-of-use assets obtained in exchange for lease obligations	2,037	276
Equity financing costs in accounts payable	74	129
Deemed dividend on preferred stock	17,378
Loss on patent litigation settlement			1,500
Forgiveness of debt	10
Receivable from warrants exercised and included in prepaid and other current assets	1,498
Warrants issued in connection with debt instruments	$ 67	$ 161	$ 847