Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating activities:
Net loss	$ (66,397)	$ (54,162)	$ (58,452)
Adjustments to reconcile net loss to net cash used in operating activities:
Allowance of bad debt	(3)	(32)	32
Inventory reserve adjustment	4,900	3,889	3,930
Depreciation and amortization	23,202	25,371	24,733
Amortization of debt issuance costs	902	865	900
Deferred income taxes, net	0	0	7,348
Loss (gain) on disposal of assets	(47)	1	15
Share-based compensation	9,600	12,121	13,046
Interest for extinguishment of debt	0	(70)	0
Extinguishment of debt	0	(6,229)	0
Unrealized foreign exchange (gain) loss	1,916	645	(1,152)
Changes in operating assets and liabilities:
Accounts receivable, trade	(12,749)	(7,020)	(8,421)
Notes receivable	7,764	(7,585)	(389)
Prepaid income tax	1	1	188
Inventories	1,150	15,786	(23,674)
Other current assets	(2,406)	867	1,220
Operating right of use asset	888	848	407
Accounts payable	12,966	7,069	(3,347)
Accrued income taxes	0	1	1
Accrued liabilities	5,260	(3,092)	44
Lease liability	(969)	(918)	(438)
Net cash used in operating activities	(14,022)	(11,644)	(44,009)
Investing activities:
Purchase of property, plant and equipment	(3,210)	(7,981)	(15,795)
Proceeds from disposal of equipment	403	114	216
Deposits and prepaid for equipment	(529)	(2,222)	(3,279)
Purchase of intangible assets	(498)	(457)	(489)
Net cash used in investing activities	(3,834)	(10,546)	(19,347)
Financing activities:
Proceeds from issuance of notes payable and long-term debt, net of debt issuance costs	0	0	6,229
Principal payments of long-term debt and notes payable	(7,336)	(4,144)	(5,233)
Proceeds from line of credit borrowings, net of debt issuance costs	143,261	122,935	95,730
Repayments of line of credit borrowings, net of debt issuance costs	(131,030)	(111,287)	(96,006)
Proceeds from bank acceptance payable	45,666	24,622	39,958
Repayments of bank acceptance payable	(40,573)	(32,465)	(31,338)
Proceeds from issuance of convertible senior notes, net of debt issuance costs	0	0	(18)
Principal payments of financing lease	(19)	(18)	(17)
Exercise of stock options	0	8	13
Payments of tax withholding on behalf of employees related to share-based compensation	(453)	(961)	(1,080)
Proceeds from common stock offering, net	1,238	15,397	39,203
Net cash provided by financing activities	10,753	14,087	47,441
Effect of exchange rate changes on cash	1,553	(876)	(999)
Net decrease in cash, cash equivalents and restricted cash	(5,550)	(8,979)	(16,914)
Cash, cash equivalents and restricted cash at beginning of period	41,136	50,115	67,029
Cash, cash equivalents and restricted cash at end of period	35,587	41,136	50,115
Supplemental disclosure of cash flow information:
Interest	5,142	4,899	4,971
Income taxes	0	1	(364)
Non-cash investing and financing activities:
Net change in accounts payable related to property and equipment additions	(164)	(4,027)	(2,326)
Net change in deposits and prepaid for equipment related to property and equipment additions	$ 67	$ 84	$ (64)