Applied Optoelectronics (AAOI) 10-Q 4 Nov 21 2021 Q3 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	9 Months Ended
	Sep. 30, 2021	Oct. 29, 2021
Document Information [Line Items]
Entity Central Index Key	0001158114
Entity Registrant Name	APPLIED OPTOELECTRONICS, INC.
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	Q3
Document Fiscal Year Focus	2021
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	001-36083
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	76-0533927
Entity Address, Address Line One	13139 Jess Pirtle Blvd.
Entity Address, City or Town	Sugar Land
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77478
City Area Code	281
Local Phone Number	295-1800
Title of 12(b) Security	Common Stock, Par value $0.001
Trading Symbol	AAOI
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		27,297,647

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current Assets
Cash and cash equivalents	$ 43,534	$ 43,425
Restricted cash	5,363	6,689
Accounts receivable - trade, net of allowance of $62 and $62, respectively	43,942	43,042
Notes receivable	8,505	401
Inventories	94,507	110,397
Prepaid income tax	2	2
Prepaid expenses and other current assets	4,717	5,213
Total current assets	200,570	209,169
Property, plant and equipment, net	242,452	252,984
Land use rights, net	5,790	5,854
Operating right of use asset	7,277	7,729
Financing right of use asset	65	88
Intangible assets, net	3,877	3,999
Other assets, net	2,493	982
TOTAL ASSETS	462,524	480,805
Current liabilities
Current portion of notes payable and long-term debt	41,254	38,265
Accounts payable	28,333	29,482
Bank acceptance payable	6,481	15,860
Current lease liability - operating	1,045	1,012
Current lease liability - financing	18	18
Accrued liabilities	16,204	18,511
Total current liabilities	93,335	103,148
Notes payable and long-term debt, less current portion	19,271	13,904
Convertible senior notes	78,472	77,854
Non-current lease liability - operating	7,410	7,926
Non-current lease liability - financing	68	82
TOTAL LIABILITIES	198,556	202,914
Stockholders' equity:
Preferred Stock; 5,000 shares authorized at $0.001 par value; no shares issued and outstanding at September 30, 2021 and December 31, 2020, respectively	0	0
Common Stock; 45,000 shares authorized at $0.001 par value; 27,175 and 25,110 shares issued and outstanding at September 30, 2021 and December 31, 2020, respectively	27	25
Additional paid-in capital	378,207	354,685
Accumulated other comprehensive income	13,865	11,690
Accumulated deficit	(128,131)	(88,509)
TOTAL STOCKHOLDERS' EQUITY	263,968	277,891
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 462,524	$ 480,805

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) shares in Thousands, $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Accounts receivable, allowance	$ 62	$ 62
Preferred stock, shares authorized (in shares)	5,000	5,000
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, shares authorized (in shares)	45,000	45,000
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares issued (in shares)	27,175	25,110
Common stock, shares outstanding (in shares)	27,175	25,110

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenue, net	$ 53,267	$ 76,608	$ 157,157	$ 182,298
Cost of goods sold	45,143	57,418	127,537	143,034
Gross profit	8,124	19,190	29,620	39,264
Operating expenses
Research and development	10,149	11,206	31,990	32,567
Sales and marketing	2,783	4,491	8,576	10,858
General and administrative	10,645	10,272	32,195	31,520
Total operating expenses	23,577	25,969	72,761	74,945
Loss from operations	(15,453)	(6,779)	(43,141)	(35,681)
Other income (expense)
Interest income	17	26	49	220
Interest expense	(1,359)	(1,480)	(4,158)	(4,424)
Other income (expense), net	998	866	7,628	2,096
Total other income (expense), net	(344)	(588)	3,519	(2,108)
Loss before income taxes	(15,797)	(7,367)	(39,622)	(37,789)
Income tax expense	0	(2,249)	0	(7,224)
Net loss	$ (15,797)	$ (9,616)	$ (39,622)	$ (45,013)
Net loss per share
Basic (in dollars per share)	$ (0.58)	$ (0.42)	$ (1.48)	$ (2.12)
Diluted (in dollars per share)	$ (0.58)	$ (0.42)	$ (1.48)	$ (2.12)
Weighted average shares used to compute net loss per share:
Basic (in shares)	27,097,372	22,744,361	26,791,415	21,275,778
Diluted (in shares)	27,097,372	22,744,361	26,791,415	21,275,778

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Net loss	$ (15,797)	$ (9,616)	$ (39,622)	$ (45,013)
Gain/ (Loss) on foreign currency translation adjustment	(421)	5,696	2,175	4,748
Comprehensive loss	$ (16,218)	$ (3,920)	$ (37,447)	$ (40,265)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Total
Balance (in shares) at Dec. 31, 2019	0	20,140
Balance at Dec. 31, 2019	$ 0	$ 20	$ 303,401	$ 430	$ (30,057)	$ 273,794
Public offering of common stock, net (in shares)	0	2,362
Public offering of common stock, net	$ 0	$ 2	22,629	0	0	22,631
Issuance of restricted stock, net of shares withheld for employee tax (in shares)	0	383
Issuance of restricted stock, net of shares withheld for employee tax	$ 0	$ 1	(813)	0	0	(812)
Share-based compensation	0	0	9,804	0	0	9,804
Foreign currency translation adjustment	0	0	0	4,748	0	4,748
Net loss	$ 0	$ 0	0	0	(45,013)	(45,013)
Stock options exercised, net of shares withheld for employee tax (in shares)	0	2
Stock options exercised, net of shares withheld for employee tax	$ 0	$ 0	14	0	0	14
Balance (in shares) at Sep. 30, 2020	0	22,887
Balance at Sep. 30, 2020	$ 0	$ 23	335,035	5,178	(75,070)	265,166
Balance (in shares) at Jun. 30, 2020	0	21,940
Balance at Jun. 30, 2020	$ 0	$ 22	323,405	(518)	(65,454)	257,455
Public offering of common stock, net (in shares)	0	780
Public offering of common stock, net	$ 0	$ 1	8,702	0	0	8,703
Issuance of restricted stock, net of shares withheld for employee tax (in shares)	0	165
Issuance of restricted stock, net of shares withheld for employee tax	$ 0	$ 0	(348)	0	0	(348)
Share-based compensation	0	0	3,265	0	0	3,265
Foreign currency translation adjustment	0	0	0	5,696	0	5,696
Net loss	$ 0	$ 0	0	0	(9,616)	(9,616)
Stock options exercised, net of shares withheld for employee tax (in shares)	0	2
Stock options exercised, net of shares withheld for employee tax	$ 0	$ 0	11			11
Balance (in shares) at Sep. 30, 2020	0	22,887
Balance at Sep. 30, 2020	$ 0	$ 23	335,035	5,178	(75,070)	265,166
Balance (in shares) at Dec. 31, 2020	0	25,110
Balance at Dec. 31, 2020	$ 0	$ 25	354,685	11,690	(88,509)	277,891
Public offering of common stock, net (in shares)	0	1,553
Public offering of common stock, net	$ 0	$ 2	15,229		0	15,231
Issuance of restricted stock, net of shares withheld for employee tax (in shares)	0	510
Issuance of restricted stock, net of shares withheld for employee tax	$ 0	$ 0	(637)	0	0	(637)
Share-based compensation	0	0	8,922	0	0	8,922
Foreign currency translation adjustment	0	0	0	2,175	0	2,175
Net loss	$ 0	$ 0	0	0	(39,622)	$ (39,622)
Stock options exercised, net of shares withheld for employee tax (in shares)	0	2				2
Stock options exercised, net of shares withheld for employee tax	$ 0	$ 0	8	0	0	$ 8
Balance (in shares) at Sep. 30, 2021	0	27,175
Balance at Sep. 30, 2021	$ 0	$ 27	378,207	13,865	(128,131)	263,968
Balance (in shares) at Jun. 30, 2021	0	26,919
Balance at Jun. 30, 2021	$ 0	$ 27	375,312	14,286	(112,334)	277,291
Public offering of common stock, net (in shares)	0	7
Public offering of common stock, net	$ 0	$ 0	1	0	0	1
Issuance of restricted stock, net of shares withheld for employee tax (in shares)	0	249
Issuance of restricted stock, net of shares withheld for employee tax	$ 0	$ 0	(236)	0	0	(236)
Share-based compensation	0	0	3,130	0	0	3,130
Foreign currency translation adjustment	0	0	0	(421)	0	(421)
Net loss	$ 0	$ 0	0	0	(15,797)	(15,797)
Balance (in shares) at Sep. 30, 2021	0	27,175
Balance at Sep. 30, 2021	$ 0	$ 27	$ 378,207	$ 13,865	$ (128,131)	$ 263,968

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating activities:
Net loss	$ (39,622)	$ (45,013)
Adjustments to reconcile net loss to net cash used in operating activities:
Inventory, LIFO Reserve, Period Charge	3,335	3,340
Depreciation and amortization	19,188	18,350
Amortization of debt issuance costs	650	673
Deferred income taxes, net	0	7,358
Loss on disposal of assets	3	15
Share-based compensation	8,922	9,804
Interest for extinguishment of debt	(70)	0
Extinguishment of debt	(6,229)	0
Unrealized foreign exchange gain	1,021	(323)
Changes in operating assets and liabilities:
Accounts receivable, trade	(900)	(16,799)
Notes receivable	(8,102)	3
Prepaid income tax	0	13
Inventories	13,551	(27,303)
Other current assets	448	(2,692)
Operating right of use asset	609	189
Accounts payable	(1,149)	23,306
Accrued liabilities	(2,372)	(620)
Lease liability	(666)	(206)
Net cash used in operating activities	(11,383)	(29,905)
Investing activities:
Purchase of property, plant and equipment	(5,555)	(12,132)
Proceeds from disposal of equipment	111	166
Deposits for equipment	(2,141)	(2,733)
Purchase of intangible assets	(324)	(376)
Net cash used in investing activities	(7,909)	(15,075)
Financing activities:
Proceeds from issuance of notes payable and long-term debt, net of debt issuance costs	0	6,229
Principal payments of long-term debt and notes payable	(3,276)	(4,066)
Proceeds from line of credit borrowings	103,925	73,700
Repayments of line of credit borrowings	(86,922)	(67,430)
Proceeds from bank acceptance payable	16,702	26,341
Repayments of bank acceptance payable	(26,150)	(19,598)
Proceeds from issuance of convertible senior notes, net of debt issuance costs	0	(18)
Principal payments of financing lease	(13)	(13)
Exercise of stock options	8	14
Payments of tax withholding on behalf of employees related to share-based compensation	(696)	(813)
Proceeds from common stock offering, net	15,397	22,632
Net cash provided by financing activities	18,975	36,978
Effect of exchange rate changes on cash	(900)	(958)
Net decrease in cash, cash equivalents and restricted cash	(1,217)	(8,960)
Cash, cash equivalents and restricted cash at beginning of period	50,114	67,028
Cash, cash equivalents and restricted cash at end of period	48,897	58,068
Supplemental disclosure of cash flow information:
Interest, net of amounts capitalized	4,691	4,739
Income taxes	1	(192)
Non-cash investing and financing activities:
Extinguishment of Debt and interest	(6,299)	0
Purchase of property and equipment with line of credit borrowings	0	941
Net change in accounts payable related to property and equipment additions	(4,147)	1,173
Net change in deposits and prepaid for equipment related to property and equipment additions	$ 83	$ 36

Note 1 - Description of Busines

Note 1 - Description of Business	9 Months Ended
	Sep. 30, 2021
Notes to Financial Statements
Business Description and Basis of Presentation [Text Block]	Note 1. ​ Business Overview ​ Applied Optoelectronics, Inc. (“AOI” or the “Company”) is a Delaware corporation. The Company is a leading, vertically integrated provider of fiber-optic networking products, primarily for four ​ The Company has manufacturing and research and development facilities located in the U.S., Taiwan and China. In the U.S., at its corporate headquarters and manufacturing facilities in Sugar Land, Texas, the Company primarily manufactures lasers and laser components and performs research and development activities for laser component and optical module products. In addition, the Company also has a research and development facility in Duluth, Georgia. The Company operates in Taipei, Taiwan and Ningbo, China through its wholly-owned subsidiary Prime World International Holdings, Ltd. (“Prime World”, incorporated in the British Virgin Islands). Prime World operates a branch in Taipei, Taiwan, which primarily manufactures transceivers and performs research and development activities for the transceiver products. Prime World is also the parent of Global Technology, Inc. (“Global”, incorporated in the People’s Republic of China). Through Global, the Company primarily manufactures certain of its data center transceiver products, including subassemblies, as well as CATV systems and equipment, and performs research and development activities for the CATV products. ​ Interim Financial Statements ​ The unaudited condensed consolidated financial statements of the Company as of September 30, 2021 December 31, 2020 three nine September 30, 2021 September 30, 2020 10 10 01 X 10 December 31, 2020 three nine September 30, 2021 not ​ Use of Estimates ​ The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported. Actual results could differ from those estimates in the consolidated financial statements and accompanying notes. Significant estimates and assumptions that impact these financial statements and the accompanying notes relate to, among other things, allowance for credit losses, inventory reserve, product warranty costs, share-based compensation expense, estimated useful lives of property and equipment, and taxes. ​

Note 2 - Significant Accounting

Note 2 - Significant Accounting Policies	9 Months Ended
	Sep. 30, 2021
Notes to Financial Statements
Significant Accounting Policies [Text Block]	Note 2. ​ There have been no three nine September 30, 2021 2020 ​ Recent Accounting Pronouncements ​ ​ Recent Accounting Pronouncements Yet to be Adopted In March 2020, 2020 04, 848 ates to alternative reference rates. ASU 2020 04 January 2021 2021 01, 2020 04 2021 01 December 31, 2022 2020 04 2021 01 may may not In August 2020, 2020 06, 470 20 815 40 two three 470 20 December 15, 2021. The Company does not In November 2020, 301 302 303 January 11, 2021, thirty February 10, 2021, first 210 not

Note 3 - Revenue Recognition

Note 3 - Revenue Recognition	9 Months Ended
	Sep. 30, 2021
Notes to Financial Statements
Revenue from Contract with Customer [Text Block]	Note 3. ​ ​ Disaggregation of Revenue ​ Revenue is classified based on the location where the product is manufactured. For additional information on the disaggregated revenues by geographical region, see Note 17, ​ Revenue is also classified by major product category and is presented below (in thousands): ​ Three months ended September 30, ​ % of % of ​ 2021 Revenue 2020 Revenue Data Center $ 23,929 44.9 % $ 55,336 72.2 % CATV 23,101 43.4 % 11,642 15.2 % Telecom 5,148 9.7 % 8,870 11.6 % FTTH 62 0.1 % 67 0.1 % Other 1,027 1.9 % 693 0.9 % Total Revenue $ 53,267 100.0 % $ 76,608 100.0 % ​ Nine months ended September 30, ​ % of % of ​ 2021 Revenue 2020 Revenue Data Center $ 72,259 46.0 % $ 141,133 77.4 % CATV 69,339 44.1 % 22,007 12.1 % Telecom 12,959 8.2 % 17,600 9.7 % FTTH 784 0.5 % 69 0.0 % Other 1,816 1.2 % 1,489 0.8 % Total Revenue $ 157,157 100.0 % $ 182,298 100.0 % ​

Note 4 - Leases

Note 4 - Leases	9 Months Ended
	Sep. 30, 2021
Notes to Financial Statements
Lessee, Operating and Finance Leases [Text Block]	Note 4. ​ The Company leases space under non-cancellable operating leases for manufacturing facilities, research and development offices and certain storage facilities and apartments. These leases do not one one ​ As most of the Company’s leases do not ​ The components of lease expense were as follows for the periods indicated (in thousands): Three months ended September 30, Nine months ended September 30, ​ 2021 2020 2021 2020 Operating lease expense $ 311 $ 299 $ 922 $ 890 Financing lease expense 8 8 24 24 Short Term lease expense 4 35 17 104 Total lease expense $ 323 $ 342 $ 963 $ 1,018 Maturities of lease liabilities are as follows for the future one September 30, 2021 ​ Operating Financing 2022 $ 1,300 $ 22 2023 1,311 22 2024 1,249 49 2025 1,244 — 2026 1,209 — 2027 and thereafter 3,197 — Total lease payments $ 9,510 $ 93 Less imputed interest (1,055 ) (7 ) Present value $ 8,455 $ 86 ​ The weighted average remaining lease term and discount rate for operating leases were as follows for the periods indicated: ​ Nine months ended September 30, ​ 2021 2020 Weighted Average Remaining Lease Term (Years) - operating leases 7.38 8.41 Weighted Average Remaining Lease Term (Years) - financing leases 2.33 3.08 Weighted Average Discount Rate - operating leases 3.23 % 3.23 % Weighted Average Discount Rate - financing leases 5.00 % 5.00 % Supplemental cash flow information related to operating leases was as follows for the periods indicated (in thousands): Nine months ended September 30, ​ 2021 2020 Cash paid for amounts included in the measurement of lease liabilities ​ ​ Operating cash flows from operating leases 980 983 Operating cash flows from financing lease 4 4 Financing cash flows from financing lease 13 13 Right-of-use assets obtained in exchange for new operating lease liabilities 121 699 ​

Note 5 - Cash, Cash Equivalents

Note 5 - Cash, Cash Equivalents and Restricted Cash	9 Months Ended
	Sep. 30, 2021
Notes to Financial Statements
Cash and Cash Equivalents Disclosure [Text Block]	Note 5. ​ The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the statement of financial position that sum to the total of the same such amounts in the statement of cash flows (in thousands): September 30, December 31, ​ 2021 2020 Cash and cash equivalents $ 43,534 $ 43,425 Restricted cash 5,363 6,689 Total cash, cash equivalents and restricted cash shown in the statement of cash flows $ 48,897 $ 50,114 ​ Restricted cash includes guarantee deposits for customs duties, China government subsidy fund, and compensating balances required for certain credit facilities. As of September 30, 2021 December 31, 2020, September 30, 2021 December 31, 2020, September 30, 2021 December 31, 2020. ​

Note 6 - Earnings (Loss) Per Sh

Note 6 - Earnings (Loss) Per Share	9 Months Ended
	Sep. 30, 2021
Notes to Financial Statements
Earnings Per Share [Text Block]	Note 6. ​ Basic net loss per share has been computed using the weighted-average number of shares of common stock outstanding during the period. Diluted net loss per share has been computed using the weighted-average number of shares of common stock and dilutive potential common shares from stock options, restricted stock units and senior convertible notes outstanding during the period. In periods with net losses, normally dilutive shares become anti-dilutive. Therefore, basic and diluted loss per share are the same. ​ The following table sets forth the computation of the basic and diluted net loss per share for the periods indicated (in thousands): ​ Three months ended September 30, Nine months ended September 30, ​ 2021 2020 2021 2020 Numerator: ​ ​ ​ ​ Net loss $ (15,797 ) $ (9,616 ) $ (39,622 ) $ (45,013 ) Denominator: ​ ​ ​ ​ Weighted average shares used to compute net loss per share ​ ​ ​ ​ Basic 27,097 22,744 26,791 21,276 Diluted 27,097 22,744 26,791 21,276 Net loss per share ​ ​ ​ ​ Basic $ (0.58 ) $ (0.42 ) $ (1.48 ) $ (2.12 ) Diluted $ (0.58 ) $ (0.42 ) $ (1.48 ) $ (2.12 ) The following potentially dilutive securities were excluded from the diluted net loss per share as their effect would have been antidilutive (in thousands): ​ Three months ended September 30, Nine months ended September 30, ​ 2021 2020 2021 2020 Employee stock options 1 51 3 27 Restricted stock units 2 113 6 9 Shares for convertible senior notes 4,587 4,587 4,587 4,587 Total antidilutive shares 4,590 4,751 4,596 4,623 ​

Note 7 - Inventories

Note 7 - Inventories	9 Months Ended
	Sep. 30, 2021
Notes to Financial Statements
Inventory Disclosure [Text Block]	Note 7. ​ Inventories, net of inventory write-downs, consist of the following for the periods indicated (in thousands): ​ ​ September 30, 2021 December 31, 2020 Raw materials $ 31,157 $ 25,555 Work in process and sub-assemblies 42,242 52,544 Finished goods 21,108 32,298 Total inventories $ 94,507 $ 110,397 ​ The lower of cost or market adjustment expensed for inventory for the three September 30, 2021 2020 nine September 30, 2021 2020 For the three September 30, 2021 2020 nine September 30, 2021 2020 ​

Note 8 - Property, Plant & Equi

Note 8 - Property, Plant & Equipment	9 Months Ended
	Sep. 30, 2021
Notes to Financial Statements
Property, Plant and Equipment Disclosure [Text Block]	Note 8. ​ Property, plant and equipment consisted of the following for the periods indicated (in thousands): ​ ​ September 30, 2021 December 31, 2020 Land improvements $ 806 $ 806 Building and improvements 89,061 88,280 Machinery and equipment 261,041 253,738 Furniture and fixtures 5,617 5,540 Computer equipment and software 12,612 11,912 Transportation equipment 709 699 ​ 369,846 360,975 Less accumulated depreciation and amortization (161,307 ) (142,434 ) ​ 208,539 218,541 Construction in progress 32,812 33,342 Land 1,101 1,101 Total property, plant and equipment, net $ 242,452 $ 252,984 ​ For the three September 30, 2021 2020 nine September 30, 2021 2020 three September 30, 2021 2020 nine September 30, 2021 2020 As of September 30, 2021 , the Company concluded that its continued loss history constitutes a triggering event as described in ASC 360 - 10 - 35 - 21, Property, Plant, and Equipment . The Company performed a recoverability test and concluded that future undiscounted cash flows exceed the carrying amount of the Company’s long-lived assets and therefore no

Note 9 - Intangible Assets, Net

Note 9 - Intangible Assets, Net	9 Months Ended
	Sep. 30, 2021
Notes to Financial Statements
Intangible Assets Disclosure [Text Block]	Note 9. ​ Intangible assets consisted of the following for the periods indicated (in thousands): ​ September 30, 2021 ​ Gross Accumulated Intangible ​ Amount amortization assets, net Patents $ 8,494 $ (4,626 ) $ 3,868 Trademarks 25 (16 ) 9 Total intangible assets $ 8,519 $ (4,642 ) $ 3,877 ​ December 31, 2020 ​ Gross Accumulated Intangible ​ Amount amortization assets, net Patents $ 8,158 $ (4,165 ) $ 3,993 Trademarks 21 (15 ) 6 Total intangible assets $ 8,179 $ (4,180 ) $ 3,999 ​ For the three September 30, 2021 2020 nine September 30, 2021 2020 At September 30, 2021 2022 $ 584 2023 584 2024 584 2025 584 2026 584 thereafter 957 $ 3,877

Note 10 - Fair Value of Financi

Note 10 - Fair Value of Financial Instruments	9 Months Ended
	Sep. 30, 2021
Notes to Financial Statements
Fair Value Disclosures [Text Block]	Note 10. ​ The following table represents a summary of the Company’s financial instruments measured at fair value on a recurring basis for the periods indicated (in thousands): ​ As of September 30, 2021 As of December 31, 2020 ​ (Level 1) (Level 2) (Level 3) Total (Level 1) (Level 2) (Level 3) Total Assets: ​ ​ ​ ​ ​ ​ ​ ​ Cash and cash equivalents $ 43,534 $ — $ — $ 43,534 $ 43,425 $ — $ — $ 43,425 Restricted cash 5,363 — — $ 5,363 6,689 — — $ 6,689 Note receivable — 8,505 — 8,505 - 401 — 401 Total assets $ 48,897 $ 8,505 $ — $ 57,402 $ 50,114 $ 401 $ — $ 50,515 Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ Bank acceptance payable $ — $ 6,481 $ — $ 6,481 $ — $ 15,860 $ — 15,860 Convertible senior notes — 67,701 — 67,701 — 70,225 — 70,225 Total liabilities $ — $ 74,182 $ — $ 74,182 $ — $ 86,085 $ — $ 86,085 ​ The carrying value amounts of accounts receivable, prepaid expenses and other current assets, accounts payable, accrued expenses and other current liabilities approximate fair value because of the short-term maturity of these instruments. The carrying value amounts of note receivable and bank acceptances approximate fair value due to the short-term nature of the debt since it renews frequently at current interest rates. The Company believes that the interest rates in effect at each period end represent the current market rates for similar borrowings. The fair value of its convertible senior debt is measured for disclosure purpose. The fair value is based on observable market prices for this debt, which is traded in less active markets and are therefore classified as a Level 2 ​

Note 11 - Notes Payable and Lon

Note 11 - Notes Payable and Long-term Debt	9 Months Ended
	Sep. 30, 2021
Notes to Financial Statements
Debt Disclosure [Text Block]	Note 11. ​ Notes payable and long-term debt consisted of the following for the periods indicated (in thousands): ​ September 30, 2021 December 31, 2020 Revolving line of credit with a U.S. bank up to $20,000 2.25% October 15, 2022 $ 19,300 $ 18,700 Paycheck Protection Program Term Note with interest at fixed rate 1.0% April 16, 2022 — 6,229 Revolving line of credit with a Taiwan bank up to $3,436 2.2% April 14, 2021 — 1,756 Notes payable to a finance company due in monthly installments with 3.5% January 21, 2022 361 1,941 Notes payable to a finance company due in monthly installments with 3.1% January 21, 2022 676 2,149 Revolving line of credit with a China bank up to $8,917 4.5% October 14, 2020 — 2,299 Revolving line of credit with a China bank up to $25,449 3.01% 4.57% May 24, 2024 17,924 11,603 Credit facility with a China bank up to $14,125 3.5% January 5, 2024 14,892 — Credit facility with a China bank up to $7,167 5.7% June 20, 2022 7,401 7,510 Sub-total 60,554 52,187 Less debt issuance costs, net (29 ) (18 ) Grand total 60,525 52,169 Less current portion (41,254 ) (38,265 ) Non-current portion $ 19,271 $ 13,904 ​ ​ ​ Bank Acceptance Notes Payable ​ ​ Bank acceptance notes issued to vendors with a zero percent interest rate $ 6,481 $ 15,860 The current portion of long-term debt is the amount payable within one September 30, 2021 ​ Maturities of long-term debt are as follows for the future one September 30, ​ 2022 $ 41,254 2023 19,271 Total outstanding $ 60,525 ​ On September 28, 2017, December 2019). ​ On September 30, 2019, $20,000,000; April 2, 2021; ( 1.0, twelve seventy-five On April 5, 2021, September 28, 2017. April 2, 2021 October 15, 2022. September 30, 2021 On April 17, 2020, 1.00%, first six November 2020, 18 April 2022. may June 14, 2021, second June 30, 2021. On September 15, 2020, November 29, 2018 January 21, 2019 ( November 29, 2018 January 21, 2019 ( NT$22,311,381, not NT$159,027,448, September 21, 2020 January 21, 2022, not September 30, 2021 $0.4 million was outstanding under the November 29, 2018 January 21, 2019 On October 7, 2020, NT$100 “NT$100M US$1M NT$100M US$1M NT$100M US$1M January 14, 2021, NT$100M three 3 April 14, 2021. may October 7, 2020 April 14, 2021. NT$100M US$1M As of September 30, 2021 , the Company has fully repaid the Taishin Credit Facility. On April 19, 2019, twelve April 14, 2020, six 6 may April 19, 2019 October 14, 2020 ( may may October 19, 2020 . On May 24, 2019, five 180 30 May 7, 2019; 9.9 April 30, 2019 $2 May 8, 2019. may 5 may As of September 30, 2021 , $17.9 million was outstanding under the SPD Credit Line and the outstanding balance of bank acceptance notes issued to vendors was $3.9 million. ​ On June 21, 2019, “¥100M ¥100M January 6, 2021, ¥100M three 3 January 5, 2024. may ¥100M June 21, 2019 January 5, 2024 ( “¥100M ¥100M may ¥100M ¥100M may ¥100M ¥100M As of September 30, 2021 , $14.9 million was outstanding under the ¥100M no ​ On June 21, 2019, three “¥50M ¥50M may ¥50M June 21, 2019 June 20, 2022 ( “¥50M ¥50M may ¥50M ¥50M may ¥50M September 30, 2021 ¥50M On October 19, 2020 , twelve 12 may October 16, 2020 October 15, 2021. may may September 30, 2021 no ​ As of September 30, 2021 December 31, 2020 As of September 30, 2021 December 31, 2020 was $4.3 million ​

Note 12 - Convertible Senior No

Note 12 - Convertible Senior Notes	9 Months Ended
	Sep. 30, 2021
Notes to Financial Statements
Convertible Debt [Text Block]	Note 12. ​ On March 5, 2019, 2024 March 5, 2019 5.00% March 15 September 15 September 15, 2019. March 15, 2024, ​ The sale of the Notes generated net proceeds of $76.4 million, after deducting the Initial Purchasers’ discounts and offering expenses payable by the Company. The Company used approximately $37.8 million of the net proceeds from the offering to fully repay the CapEx Loan and Term Loan with Truist Bank and the remainder will be used for general corporate purposes. ​ The following table presents the carrying value of the Notes for the periods indicated (in thousands): ​ September 30, December 31, ​ 2021 2020 Principal $ 80,500 $ 80,500 Unamortized debt issuance costs (2,028 ) (2,646 ) Net carrying amount $ 78,472 $ 77,854 ​ The Notes are convertible at the option of holders of the Notes at any time until the close of business on the scheduled trading day immediately preceding the maturity date. Upon conversion, holders of the Notes will receive shares of the Company’s common stock, together, if applicable, with cash in lieu of any fractional share, at the then-applicable conversion rate. The initial conversion rate is 56.9801 shares of the Company’s common stock per $1,000 principal amount of Notes (representing an initial conversion price of approximately $17.55 per share of common stock, which represents an initial conversion premium of approximately 30% above the closing price of $13.50 per share of the Company’s common stock on February 28, 2019 March 15, 2022, Initially there are no Holders may The Company may not March 15, 2022. March 15, 2022, may not The Indenture contains covenants that limit the Company’s ability and the ability of our subsidiaries to, among other things: (i) incur or guarantee additional indebtedness or issue disqualified stock; and (ii) create or incur liens. ​ Pursuant to the guidance in ASC 815 40, Contracts in Entity’s Own Equity 815 40, 1 2 815 40 25 7 815 40 25 10. not 470 20, Debt with Conversion and Other Options The Company incurred approximately $4.1 million in transaction costs in connection with the issuance of the Notes. These costs were recognized as a reduction of the carrying amount of the Notes utilizing the effective interest method and are being amortized over the term of the Notes. ​ The following table sets forth interest expense information related to the Notes (in thousands): ​ Three months ended September 30, Nine months ended September 30, ​ 2021 2020 2021 2020 Contractual interest expense $ 1,006 $ 1,006 $ 3,018 $ 3,018 Amortization of debt issuance costs 208 209 618 623 Total interest cost $ 1,214 $ 1,215 $ 3,636 $ 3,641 Effective interest rate 5.1 % 5.1 % 5.1 % 5.1 % ​

Note 13 - Accrued Liabilities

Note 13 - Accrued Liabilities	9 Months Ended
	Sep. 30, 2021
Notes to Financial Statements
Accounts Payable, Accrued Liabilities, and Other Liabilities Disclosure, Current [Text Block]	Note 13. ​ Accrued liabilities consisted of the following for the periods indicated (in thousands): ​ September 30, 2021 December 31, 2020 Accrued payroll $ 8,348 $ 10,517 Accrued employee benefits 3,247 3,057 Accrued state and local taxes 1,390 251 Accrued interest 351 1,256 Advance payments 480 303 Accrued product warranty 272 703 Accrued commission expenses 903 974 Accrued professional fees 293 377 Accrued shipping and tariff expenses 235 526 Accrued other 685 547 Total accrued liabilities $ 16,204 $ 18,511 ​

Note 14 - Other Income and Expe

Note 14 - Other Income and Expense	9 Months Ended
	Sep. 30, 2021
Notes to Financial Statements
Other Nonoperating Income and Expense [Text Block]	Note 14. ​ Other income and (expense) consisted of the following for the periods indicated (in thousands): Three months ended September 30, Nine months ended September 30, ​ 2021 2020 2021 2020 Foreign exchange transaction gain (loss) $ (1 ) $ (271 ) $ 217 $ (18 ) Government subsidy income 826 847 980 1,828 Other non-operating gain 171 296 205 301 Loan forgiveness — — 6,229 — Gain (loss) on disposal of assets 2 (6 ) (3 ) (15 ) Total other income, net $ 998 $ 866 $ 7,628 $ 2,096 ​

Note 15 - Share-based Compensat

Note 15 - Share-based Compensation	9 Months Ended
	Sep. 30, 2021
Notes to Financial Statements
Share-based Payment Arrangement [Text Block]	Note 15. ​ Equity Plans ​ The Company’s board of directors and stockholders approved the following equity plans: ​ ● the 2006 ● the 2013 “2013 ● the 2021 “2021 The Company issued stock options, restricted stock awards (“RSAs”) and restricted stock units (“RSUs”) to employees, consultants and non-employee directors. Stock option awards generally vest over a four ten may September 2013, third ​ Stock Options ​ Options have been granted to the Company’s employees under the two first ten ​ The following is a summary of option activity (in thousands, except per share data): ​ ​ ​ Weighted ​ Weighted ​ ​ ​ Weighted Average ​ Average ​ ​ ​ Average Share Price Weighted Remaining Aggregate ​ Number of Exercise on Date of Average Contractual Intrinsic ​ shares Price Exercise Fair Value Life Value ​ (in thousands, except price data) Outstanding at January 1, 2021 276 $ 10.29 ​ $ 5.41 2.67 $ 54 Exercised (2 ) $ 6.00 $ 0.40 ​ 7 Forfeited (4 ) $ 10.46 $ 5.64 ​ 1 Outstanding, September 30, 2021 270 $ 10.32 ​ $ 5.44 1.94 6 Exercisable, September 30, 2021 270 $ 10.32 ​ ​ 1.94 6 Vested and expected to vest 270 $ 10.33 ​ ​ 1.94 6 As of September 30, 2021 no ​ Restricted Stock Units/Awards ​ The following is a summary of RSU/RSA activity (in thousands, except per share data): ​ ​ Weighted ​ ​ ​ ​ Average Share Weighted Aggregate ​ Number of Price on Date Average Fair Intrinsic ​ shares of Release Value Value ​ (in thousands, except price data) Outstanding at January 1, 2021 1,325 ​ $ 14.97 $ 11,279 Granted 1,732 ​ 10.12 16,007 Released (590 ) $ 8.59 15.87 5,069 Cancelled/Forfeited (73 ) ​ 13.05 527 Outstanding, September 30, 2021 2,394 ​ 11.30 17,189 Vested and expected to vest 2,394 ​ 11.30 17,189 ​ As of September 30, 2021 Performance Based Incentive Plan ​ June 2021, three third Share-Based Compensation ​ Employee share-based compensation expenses recognized for the periods indicated (in thousands): ​ Three months ended Nine months ended ​ September 30, September 30, ​ 2021 2020 2021 2020 Share-based compensation - by expense type ​ ​ Cost of goods sold $ 222 $ 230 $ 689 $ 712 Research and development 489 706 1,682 2,098 Sales and marketing 272 298 820 884 General and administrative 2,146 2,031 5,731 6,110 Total share-based compensation expense $ 3,129 $ 3,265 $ 8,922 $ 9,804

Note 16 - Income Taxes

Note 16 - Income Taxes	9 Months Ended
	Sep. 30, 2021
Notes to Financial Statements
Income Tax Disclosure [Text Block]	Note 16. ​ The Company’s effective tax rate for the three September 30, 2021 2020 three September 30, 2021, three September 30, 2020, The Company's effective tax rate for the nine September 30, 2021 2020 nine September 30, 2021, nine September 30, 2020, The Company continually monitors and performs an assessment of the realizability of its DTAs, including an analysis of factors such as future taxable income, reversal of existing taxable temporary differences, and tax planning strategies. In assessing the need for a valuation allowance, the Company considered both positive and negative evidence related to the likelihood of realization of deferred tax assets using a “more likely than not” September 30, 2021 In response to the COVID- 19 March 27, 2020. December 27, 2020, 2020 2021, March 1, 2021. (“PPP”), 2021 2022 not 2021.

Note 17 - Geographic Informatio

Note 17 - Geographic Information	9 Months Ended
	Sep. 30, 2021
Notes to Financial Statements
Segment Reporting Disclosure [Text Block]	Note 17. ​ The Company operates in one reportable segment. The Company’s Chief Executive Officer, who is considered to be the chief operating decision maker, manages the Company’s operations as a whole and reviews financial information presented on a consolidated basis, accompanied by information about product revenue, for purposes of evaluating financial performance and allocating resources. ​ The following tables set forth the Company’s revenue and asset information by geographic region. Revenue is classified based on the location of where the product is manufactured. Long-lived assets in the tables below comprise only property, plant, equipment and intangible assets (in thousands): ​ Three months ended September 30, Nine months ended September 30, ​ 2021 2020 2021 2020 Revenues: ​ ​ ​ ​ United States $ 4,547 $ 4,887 $ 11,451 $ 13,383 Taiwan 19,562 45,821 75,282 105,196 China 29,158 25,900 70,424 63,719 ​ $ 53,267 $ 76,608 $ 157,157 $ 182,298 As of the period ended ​ September 30, December 31, ​ 2021 2020 Long-lived assets: ​ ​ United States $ 87,241 $ 90,999 Taiwan 65,394 71,080 China 106,826 108,575 ​ $ 259,461 $ 270,654 ​

Note 18 - Contingencies

Note 18 - Contingencies	9 Months Ended
	Sep. 30, 2021
Notes to Financial Statements
Commitments and Contingencies Disclosure [Text Block]	Note 18. ​ Litigation ​ Overview From time to time, the Company may not Except for the lawsuits described below, the Company believes that there are no Class Action and Shareholder Derivative Litigation On August 7, 2018, Lei Jin, derivatively on behalf of Applied Optoelectronics, Inc. v. Chih-Hsiang ( “ Thompson ” ) Lin, Stefan J. Murry, William H. Yeh, Alex Ignatiev, Richard B. Black, Min-Chu Chen, Alan Moore, and Che-Wei Lin and Applied Optoelectronics, Inc. , No. 4:18 02713 14 Mona Abouzied v. Applied Optoelectronics, Inc., Chih-Hsiang (Thompson) Lin, and Stefan J. Murry, et al. , Case No. 4:17 02399, 2020. December 18, 2018, second Yiu Kwong Ng v. Chih-Hsiang ( “ Thompson ” ) Lin, Stefan J. Murry, William H. Yeh, Alex Ignatiev, Richard B. Black, Min-Chu Chen, Alan Moore, and Che-Wei Lin and Applied Optoelectronics, Inc. , No. 4:18 4751 Jin complaint and additional factual allegations regarding our announcement on September 28, 2018 25G January 11, 2019, C ourt consolidated these two January 15, 2019, C ourt entered an order staying the actions pending the resolution of the securities class actions. On June 24, 2020, July 2, 2020, C ourt entered the stipulated scheduling order on the same date, under which Defendants were required to file and serve their response or responsive pleading to the complaint by August 3, 2020. December 2, 2020. December 2, 2020, December 7, 2020, January 13, 2021. March 1, 2021. On June 25, 2021, June 28, 2021, 30 late August . On August 30, 2021, August 31, 2021 November 4, 2021. November 4, 2021.

Note 19 - Subsequent Events

Note 19 - Subsequent Events	9 Months Ended
	Sep. 30, 2021
Notes to Financial Statements
Subsequent Events [Text Block]	Note 19. ​ The Company repaid its revolving bank line of credit with Truist Bank in the amount of $19.3 million in October 2021.

Significant Accounting Policies

Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
New Accounting Pronouncements, Policy [Policy Text Block]	Recent Accounting Pronouncements ​ ​ Recent Accounting Pronouncements Yet to be Adopted In March 2020, 2020 04, 848 ates to alternative reference rates. ASU 2020 04 January 2021 2021 01, 2020 04 2021 01 December 31, 2022 2020 04 2021 01 may may not In August 2020, 2020 06, 470 20 815 40 two three 470 20 December 15, 2021. The Company does not In November 2020, 301 302 303 January 11, 2021, thirty February 10, 2021, first 210 not

Note 3 - Revenue Recognition (T

Note 3 - Revenue Recognition (Tables)	9 Months Ended
	Sep. 30, 2021
Notes Tables
Disaggregation of Revenue [Table Text Block]	Three months ended September 30, ​ % of % of ​ 2021 Revenue 2020 Revenue Data Center $ 23,929 44.9 % $ 55,336 72.2 % CATV 23,101 43.4 % 11,642 15.2 % Telecom 5,148 9.7 % 8,870 11.6 % FTTH 62 0.1 % 67 0.1 % Other 1,027 1.9 % 693 0.9 % Total Revenue $ 53,267 100.0 % $ 76,608 100.0 % Nine months ended September 30, ​ % of % of ​ 2021 Revenue 2020 Revenue Data Center $ 72,259 46.0 % $ 141,133 77.4 % CATV 69,339 44.1 % 22,007 12.1 % Telecom 12,959 8.2 % 17,600 9.7 % FTTH 784 0.5 % 69 0.0 % Other 1,816 1.2 % 1,489 0.8 % Total Revenue $ 157,157 100.0 % $ 182,298 100.0 %

Note 4 - Leases (Tables)

Note 4 - Leases (Tables)	9 Months Ended
	Sep. 30, 2021
Notes Tables
Lease, Cost [Table Text Block]	Three months ended September 30, Nine months ended September 30, ​ 2021 2020 2021 2020 Operating lease expense $ 311 $ 299 $ 922 $ 890 Financing lease expense 8 8 24 24 Short Term lease expense 4 35 17 104 Total lease expense $ 323 $ 342 $ 963 $ 1,018 Nine months ended September 30, ​ 2021 2020 Weighted Average Remaining Lease Term (Years) - operating leases 7.38 8.41 Weighted Average Remaining Lease Term (Years) - financing leases 2.33 3.08 Weighted Average Discount Rate - operating leases 3.23 % 3.23 % Weighted Average Discount Rate - financing leases 5.00 % 5.00 % Nine months ended September 30, ​ 2021 2020 Cash paid for amounts included in the measurement of lease liabilities ​ ​ Operating cash flows from operating leases 980 983 Operating cash flows from financing lease 4 4 Financing cash flows from financing lease 13 13 Right-of-use assets obtained in exchange for new operating lease liabilities 121 699
Lessee, Operating and Finance Lease, Liability, Maturity [Table Text Block]	Operating Financing 2022 $ 1,300 $ 22 2023 1,311 22 2024 1,249 49 2025 1,244 — 2026 1,209 — 2027 and thereafter 3,197 — Total lease payments $ 9,510 $ 93 Less imputed interest (1,055 ) (7 ) Present value $ 8,455 $ 86

Note 5 - Cash, Cash Equivalen_2

Note 5 - Cash, Cash Equivalents and Restricted Cash (Tables)	9 Months Ended
	Sep. 30, 2021
Notes Tables
Schedule of Cash and Cash Equivalents [Table Text Block]	September 30, December 31, ​ 2021 2020 Cash and cash equivalents $ 43,534 $ 43,425 Restricted cash 5,363 6,689 Total cash, cash equivalents and restricted cash shown in the statement of cash flows $ 48,897 $ 50,114

Note 6 - Earnings (Loss) Per _2

Note 6 - Earnings (Loss) Per Share (Tables)	9 Months Ended
	Sep. 30, 2021
Notes Tables
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	Three months ended September 30, Nine months ended September 30, ​ 2021 2020 2021 2020 Numerator: ​ ​ ​ ​ Net loss $ (15,797 ) $ (9,616 ) $ (39,622 ) $ (45,013 ) Denominator: ​ ​ ​ ​ Weighted average shares used to compute net loss per share ​ ​ ​ ​ Basic 27,097 22,744 26,791 21,276 Diluted 27,097 22,744 26,791 21,276 Net loss per share ​ ​ ​ ​ Basic $ (0.58 ) $ (0.42 ) $ (1.48 ) $ (2.12 ) Diluted $ (0.58 ) $ (0.42 ) $ (1.48 ) $ (2.12 )
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]	Three months ended September 30, Nine months ended September 30, ​ 2021 2020 2021 2020 Employee stock options 1 51 3 27 Restricted stock units 2 113 6 9 Shares for convertible senior notes 4,587 4,587 4,587 4,587 Total antidilutive shares 4,590 4,751 4,596 4,623

Note 7 - Inventories (Tables)

Note 7 - Inventories (Tables)	9 Months Ended
	Sep. 30, 2021
Notes Tables
Schedule of Inventory, Current [Table Text Block]	​ September 30, 2021 December 31, 2020 Raw materials $ 31,157 $ 25,555 Work in process and sub-assemblies 42,242 52,544 Finished goods 21,108 32,298 Total inventories $ 94,507 $ 110,397

Note 8 - Property, Plant & Eq_2

Note 8 - Property, Plant & Equipment (Tables)	9 Months Ended
	Sep. 30, 2021
Notes Tables
Property, Plant and Equipment [Table Text Block]	​ September 30, 2021 December 31, 2020 Land improvements $ 806 $ 806 Building and improvements 89,061 88,280 Machinery and equipment 261,041 253,738 Furniture and fixtures 5,617 5,540 Computer equipment and software 12,612 11,912 Transportation equipment 709 699 ​ 369,846 360,975 Less accumulated depreciation and amortization (161,307 ) (142,434 ) ​ 208,539 218,541 Construction in progress 32,812 33,342 Land 1,101 1,101 Total property, plant and equipment, net $ 242,452 $ 252,984

Note 9 - Intangible Assets, N_2

Note 9 - Intangible Assets, Net (Tables)	9 Months Ended
	Sep. 30, 2021
Notes Tables
Schedule of Finite-Lived Intangible Assets [Table Text Block]	September 30, 2021 ​ Gross Accumulated Intangible ​ Amount amortization assets, net Patents $ 8,494 $ (4,626 ) $ 3,868 Trademarks 25 (16 ) 9 Total intangible assets $ 8,519 $ (4,642 ) $ 3,877 December 31, 2020 ​ Gross Accumulated Intangible ​ Amount amortization assets, net Patents $ 8,158 $ (4,165 ) $ 3,993 Trademarks 21 (15 ) 6 Total intangible assets $ 8,179 $ (4,180 ) $ 3,999
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]	2022 $ 584 2023 584 2024 584 2025 584 2026 584 thereafter 957 $ 3,877

Note 10 - Fair Value of Finan_2

Note 10 - Fair Value of Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2021
Notes Tables
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]	As of September 30, 2021 As of December 31, 2020 ​ (Level 1) (Level 2) (Level 3) Total (Level 1) (Level 2) (Level 3) Total Assets: ​ ​ ​ ​ ​ ​ ​ ​ Cash and cash equivalents $ 43,534 $ — $ — $ 43,534 $ 43,425 $ — $ — $ 43,425 Restricted cash 5,363 — — $ 5,363 6,689 — — $ 6,689 Note receivable — 8,505 — 8,505 - 401 — 401 Total assets $ 48,897 $ 8,505 $ — $ 57,402 $ 50,114 $ 401 $ — $ 50,515 Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ Bank acceptance payable $ — $ 6,481 $ — $ 6,481 $ — $ 15,860 $ — 15,860 Convertible senior notes — 67,701 — 67,701 — 70,225 — 70,225 Total liabilities $ — $ 74,182 $ — $ 74,182 $ — $ 86,085 $ — $ 86,085

Note 11 - Notes Payable and L_2

Note 11 - Notes Payable and Long-term Debt (Tables)	9 Months Ended
	Sep. 30, 2021
Notes Tables
Schedule of Debt [Table Text Block]	September 30, 2021 December 31, 2020 Revolving line of credit with a U.S. bank up to $20,000 2.25% October 15, 2022 $ 19,300 $ 18,700 Paycheck Protection Program Term Note with interest at fixed rate 1.0% April 16, 2022 — 6,229 Revolving line of credit with a Taiwan bank up to $3,436 2.2% April 14, 2021 — 1,756 Notes payable to a finance company due in monthly installments with 3.5% January 21, 2022 361 1,941 Notes payable to a finance company due in monthly installments with 3.1% January 21, 2022 676 2,149 Revolving line of credit with a China bank up to $8,917 4.5% October 14, 2020 — 2,299 Revolving line of credit with a China bank up to $25,449 3.01% 4.57% May 24, 2024 17,924 11,603 Credit facility with a China bank up to $14,125 3.5% January 5, 2024 14,892 — Credit facility with a China bank up to $7,167 5.7% June 20, 2022 7,401 7,510 Sub-total 60,554 52,187 Less debt issuance costs, net (29 ) (18 ) Grand total 60,525 52,169 Less current portion (41,254 ) (38,265 ) Non-current portion $ 19,271 $ 13,904 ​ ​ ​ Bank Acceptance Notes Payable ​ ​ Bank acceptance notes issued to vendors with a zero percent interest rate $ 6,481 $ 15,860 2022 $ 41,254 2023 19,271 Total outstanding $ 60,525

Note 12 - Convertible Senior _2

Note 12 - Convertible Senior Notes (Tables)	9 Months Ended
	Sep. 30, 2021
Notes Tables
Convertible Debt [Table Text Block]	September 30, December 31, ​ 2021 2020 Principal $ 80,500 $ 80,500 Unamortized debt issuance costs (2,028 ) (2,646 ) Net carrying amount $ 78,472 $ 77,854
Interest Income and Interest Expense Disclosure [Table Text Block]	Three months ended September 30, Nine months ended September 30, ​ 2021 2020 2021 2020 Contractual interest expense $ 1,006 $ 1,006 $ 3,018 $ 3,018 Amortization of debt issuance costs 208 209 618 623 Total interest cost $ 1,214 $ 1,215 $ 3,636 $ 3,641 Effective interest rate 5.1 % 5.1 % 5.1 % 5.1 %

Note 13 - Accrued Liabilities (

Note 13 - Accrued Liabilities (Tables)	9 Months Ended
	Sep. 30, 2021
Notes Tables
Schedule of Accrued Liabilities [Table Text Block]	September 30, 2021 December 31, 2020 Accrued payroll $ 8,348 $ 10,517 Accrued employee benefits 3,247 3,057 Accrued state and local taxes 1,390 251 Accrued interest 351 1,256 Advance payments 480 303 Accrued product warranty 272 703 Accrued commission expenses 903 974 Accrued professional fees 293 377 Accrued shipping and tariff expenses 235 526 Accrued other 685 547 Total accrued liabilities $ 16,204 $ 18,511

Note 14 - Other Income and Ex_2

Note 14 - Other Income and Expense (Tables)	9 Months Ended
	Sep. 30, 2021
Notes Tables
Schedule of Other Nonoperating Income (Expense) [Table Text Block]	Three months ended September 30, Nine months ended September 30, ​ 2021 2020 2021 2020 Foreign exchange transaction gain (loss) $ (1 ) $ (271 ) $ 217 $ (18 ) Government subsidy income 826 847 980 1,828 Other non-operating gain 171 296 205 301 Loan forgiveness — — 6,229 — Gain (loss) on disposal of assets 2 (6 ) (3 ) (15 ) Total other income, net $ 998 $ 866 $ 7,628 $ 2,096

Note 15 - Share-based Compens_2

Note 15 - Share-based Compensation (Tables)	9 Months Ended
	Sep. 30, 2021
Notes Tables
Share-based Payment Arrangement, Option, Activity [Table Text Block]	​ ​ Weighted ​ Weighted ​ ​ ​ Weighted Average ​ Average ​ ​ ​ Average Share Price Weighted Remaining Aggregate ​ Number of Exercise on Date of Average Contractual Intrinsic ​ shares Price Exercise Fair Value Life Value ​ (in thousands, except price data) Outstanding at January 1, 2021 276 $ 10.29 ​ $ 5.41 2.67 $ 54 Exercised (2 ) $ 6.00 $ 0.40 ​ 7 Forfeited (4 ) $ 10.46 $ 5.64 ​ 1 Outstanding, September 30, 2021 270 $ 10.32 ​ $ 5.44 1.94 6 Exercisable, September 30, 2021 270 $ 10.32 ​ ​ 1.94 6 Vested and expected to vest 270 $ 10.33 ​ ​ 1.94 6
Share-based Payment Arrangement, Restricted Stock Unit, Activity [Table Text Block]	​ Weighted ​ ​ ​ ​ Average Share Weighted Aggregate ​ Number of Price on Date Average Fair Intrinsic ​ shares of Release Value Value ​ (in thousands, except price data) Outstanding at January 1, 2021 1,325 ​ $ 14.97 $ 11,279 Granted 1,732 ​ 10.12 16,007 Released (590 ) $ 8.59 15.87 5,069 Cancelled/Forfeited (73 ) ​ 13.05 527 Outstanding, September 30, 2021 2,394 ​ 11.30 17,189 Vested and expected to vest 2,394 ​ 11.30 17,189
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]	Three months ended Nine months ended ​ September 30, September 30, ​ 2021 2020 2021 2020 Share-based compensation - by expense type ​ ​ Cost of goods sold $ 222 $ 230 $ 689 $ 712 Research and development 489 706 1,682 2,098 Sales and marketing 272 298 820 884 General and administrative 2,146 2,031 5,731 6,110 Total share-based compensation expense $ 3,129 $ 3,265 $ 8,922 $ 9,804

Note 17 - Geographic Informat_2

Note 17 - Geographic Information (Tables)	9 Months Ended
	Sep. 30, 2021
Notes Tables
Revenue from External Customers by Geographic Areas [Table Text Block]	Three months ended September 30, Nine months ended September 30, ​ 2021 2020 2021 2020 Revenues: ​ ​ ​ ​ United States $ 4,547 $ 4,887 $ 11,451 $ 13,383 Taiwan 19,562 45,821 75,282 105,196 China 29,158 25,900 70,424 63,719 ​ $ 53,267 $ 76,608 $ 157,157 $ 182,298
Long-lived Assets by Geographic Areas [Table Text Block]	As of the period ended ​ September 30, December 31, ​ 2021 2020 Long-lived assets: ​ ​ United States $ 87,241 $ 90,999 Taiwan 65,394 71,080 China 106,826 108,575 ​ $ 259,461 $ 270,654

Note 3 - Revenue Recognition -

Note 3 - Revenue Recognition - Revenue by Major Product Category (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Total Revenue	$ 53,267	$ 76,608	$ 157,157	$ 182,298
Percent of Revenue	100.00%	100.00%	100.00%	100.00%
Data Center [Member]
Total Revenue	$ 23,929	$ 55,336	$ 72,259	$ 141,133
Percent of Revenue	44.90%	72.20%	46.00%	77.40%
CATV [Member]
Total Revenue	$ 23,101	$ 11,642	$ 69,339	$ 22,007
Percent of Revenue	43.40%	15.20%	44.10%	12.10%
Telecom [Member]
Total Revenue	$ 5,148	$ 8,870	$ 12,959	$ 17,600
Percent of Revenue	9.70%	11.60%	8.20%	9.70%
FTTH [Member]
Total Revenue	$ 62	$ 67	$ 784	$ 69
Percent of Revenue	0.10%	0.10%	0.50%	0.00%
Product and Service, Other [Member]
Total Revenue	$ 1,027	$ 693	$ 1,816	$ 1,489
Percent of Revenue	1.90%	0.90%	1.20%	0.80%

Note 4 - Leases - Components of

Note 4 - Leases - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Operating lease expense	$ 311	$ 299	$ 922	$ 890
Financing lease expense	8	8	24	24
Short Term lease expense	4	35	17	104
Total lease expense	$ 323	$ 342	$ 963	$ 1,018
Weighted Average Remaining Lease Term (Years) - operating leases (Year)	7 years 4 months 17 days	8 years 4 months 28 days	7 years 4 months 17 days	8 years 4 months 28 days
Weighted Average Remaining Lease Term (Years) - financing leases (Year)	2 years 3 months 29 days	3 years 29 days	2 years 3 months 29 days	3 years 29 days
Weighted Average Discount Rate - operating leases	3.23%	3.23%	3.23%	3.23%
Weighted Average Discount Rate - financing leases	5.00%	5.00%	5.00%	5.00%
Operating cash flows from operating leases			$ 980	$ 983
Operating cash flows from financing lease			4	4
Financing cash flows from financing lease			13	13
Right-of-use assets obtained in exchange for new operating lease liabilities			$ 121	$ 699

Note 4 - Leases - Maturities of

Note 4 - Leases - Maturities of Lease Liabilities (Details) $ in Thousands	Sep. 30, 2021USD ($)
2022, operating leases	$ 1,300
2022, financing leases	22
2023, operating leases	1,311
2023, financing leases	22
2024, operating leases	1,249
2024, financing leases	49
2025, operating leases	1,244
2025, financing leases	0
2026, operating leases	1,209
2026, financing leases	0
2027 and thereafter, operating leases	3,197
2027 and thereafter, financing leases	0
Total operating lease payments	9,510
Total financing lease payments	93
Less imputed interest, operating leases	(1,055)
Less imputed interest, financing leases	(7)
Present value, operating leases	8,455
Present value, financing leases	$ 86

Note 5 - Cash, Cash Equivalen_3

Note 5 - Cash, Cash Equivalents and Restricted Cash (Details Textual) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Restricted Cash and Cash Equivalents, Current, Total	$ 5,363	$ 6,689
CHINA
Certificates of Deposit, at Carrying Value	2,000	500
Bankers Acceptance [Member]
Restricted Cash and Cash Equivalents, Current, Total	$ 2,300	4,900
Guarantee Deposits for Customs Duties [Member]
Restricted Cash and Cash Equivalents, Current, Total		$ 1,000

Note 5 - Cash, Cash Equivalen_4

Note 5 - Cash, Cash Equivalents and Restricted Cash - Summary of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Cash and cash equivalents	$ 43,534	$ 43,425
Restricted cash	5,363	6,689
Total cash, cash equivalents and restricted cash shown in the statement of cash flows	$ 48,897	$ 50,114

Note 6 - Earnings (Loss) Per _3

Note 6 - Earnings (Loss) Per Share - Computation of Basic and Diluted Net Income (Loss) per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Net loss	$ (15,797)	$ (9,616)	$ (39,622)	$ (45,013)
Basic (in shares)	27,097,372	22,744,361	26,791,415	21,275,778
Diluted (in shares)	27,097,372	22,744,361	26,791,415	21,275,778
Basic (in dollars per share)	$ (0.58)	$ (0.42)	$ (1.48)	$ (2.12)
Diluted (in dollars per share)	$ (0.58)	$ (0.42)	$ (1.48)	$ (2.12)

Note 6 - Earnings (Loss) Per _4

Note 6 - Earnings (Loss) Per Share - Potentially Dilutive Securities Excluded from Diluted Net Income (Loss) per Share (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Total antidilutive shares (in shares)	4,590	4,751	4,596	4,623
Share-based Payment Arrangement, Option [Member]
Total antidilutive shares (in shares)	1	51	3	27
Restricted Stock Units (RSUs) [Member]
Total antidilutive shares (in shares)	2	113	6	9
Convertible Debt Securities [Member]
Total antidilutive shares (in shares)	4,587	4,587	4,587	4,587

Note 7 - Inventories (Details T

Note 7 - Inventories (Details Textual) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Inventory, LIFO Reserve, Period Charge	$ 1,100	$ 400	$ 3,335	$ 3,340
Inventory Write-down	$ 4,200	$ 8,400	$ 15,000	$ 14,700

Note 7 - Inventories - Inventor

Note 7 - Inventories - Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Raw materials	$ 31,157	$ 25,555
Work in process and sub-assemblies	42,242	52,544
Finished goods	21,108	32,298
Total inventories	$ 94,507	$ 110,397

Note 8 - Property, Plant & Eq_3

Note 8 - Property, Plant & Equipment (Details Textual) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Depreciation, Total	$ 6.2	$ 6.1	$ 18.7	$ 17.9
Interest Paid, Capitalized, Investing Activities	$ 0.3	$ 0.1	$ 0.6	$ 0.3

Note 8 - Property, Plant & Eq_4

Note 8 - Property, Plant & Equipment - Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Property, plant and equipment, gross	$ 369,846	$ 360,975
Less accumulated depreciation and amortization	(161,307)	(142,434)
Property, plant and equipment, net before construction in progress and land	208,539	218,541
Property, plant and equipment, net	242,452	252,984
Land Improvements [Member]
Property, plant and equipment, gross	806	806
Building and Building Improvements [Member]
Property, plant and equipment, gross	89,061	88,280
Machinery and Equipment [Member]
Property, plant and equipment, gross	261,041	253,738
Furniture and Fixtures [Member]
Property, plant and equipment, gross	5,617	5,540
Computer Equipment and Software [Member]
Property, plant and equipment, gross	12,612	11,912
Vehicles [Member]
Property, plant and equipment, gross	709	699
Construction in Progress [Member]
Property, plant and equipment, net	32,812	33,342
Land [Member]
Property, plant and equipment, net	$ 1,101	$ 1,101

Note 9 - Intangible Assets, N_3

Note 9 - Intangible Assets, Net (Details Textual) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Amortization of Intangible Assets, Total	$ 0.1	$ 0.1	$ 0.5	$ 0.4
Finite-Lived Intangible Assets, Remaining Amortization Period (Year)			7 years

Note 9 - Intangible Assets, N_4

Note 9 - Intangible Assets, Net - Finite Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Intangible assets, gross amount	$ 8,519	$ 8,179
Intangible assets, accumulated amortization	(4,642)	(4,180)
Intangible assets, net	3,877	3,999
Patents [Member]
Intangible assets, gross amount	8,494	8,158
Intangible assets, accumulated amortization	(4,626)	(4,165)
Intangible assets, net	3,868	3,993
Trademarks [Member]
Intangible assets, gross amount	25	21
Intangible assets, accumulated amortization	(16)	(15)
Intangible assets, net	$ 9	$ 6

Note 9 - Intangible Assets, N_5

Note 9 - Intangible Assets, Net - Future Amortization Expense (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
2022	$ 584
2023	584
2024	584
2025	584
2026	584
thereafter	957
Finite-Lived Intangible Assets, Net, Ending Balance	$ 3,877	$ 3,999

Note 10 - Fair Value of Finan_3

Note 10 - Fair Value of Financial Instruments - Financial Instruments Measured at Fair Value on a Recurring Basis (Details) - Fair Value, Recurring [Member] - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Cash and cash equivalents	$ 43,534	$ 43,425
Restricted cash	5,363	6,689
Note receivable	8,505	401
Total assets	57,402	50,515
Bank acceptance payable	6,481	15,860
Convertible senior notes	67,701	70,225
Total liabilities	74,182	86,085
Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	43,534	43,425
Restricted cash	5,363	6,689
Note receivable	0	0
Total assets	48,897	50,114
Bank acceptance payable	0	0
Convertible senior notes	0	0
Total liabilities	0	0
Fair Value, Inputs, Level 2 [Member]
Cash and cash equivalents	0	0
Restricted cash	0	0
Note receivable	8,505	401
Total assets	8,505	401
Bank acceptance payable	6,481	15,860
Convertible senior notes	67,701	70,225
Total liabilities	74,182	86,085
Fair Value, Inputs, Level 3 [Member]
Cash and cash equivalents	0	0
Restricted cash	0	0
Note receivable	0	0
Total assets	0	0
Bank acceptance payable	0	0
Convertible senior notes	0	0
Total liabilities	$ 0	$ 0

Note 11 - Notes Payable and L_3

Note 11 - Notes Payable and Long-term Debt (Details Textual)	Jan. 21, 2022USD ($)	Apr. 05, 2021USD ($)	Oct. 07, 2020USD ($)	Sep. 15, 2020USD ($)	Sep. 15, 2020TWD ($)	Apr. 17, 2020USD ($)	Sep. 30, 2019USD ($)	Jun. 21, 2019USD ($)	May 24, 2019USD ($)	Apr. 19, 2019USD ($)	Sep. 30, 2021USD ($)	Sep. 30, 2020USD ($)	Dec. 31, 2020USD ($)	Oct. 19, 2020USD ($)	Oct. 19, 2020CNY (¥)	Oct. 07, 2020TWD ($)	Jun. 21, 2019CNY (¥)	May 24, 2019CNY (¥)	Apr. 19, 2019CNY (¥)	Mar. 05, 2019USD ($)	Jan. 21, 2019USD ($)	Nov. 29, 2018USD ($)
Payments to Acquire Property, Plant, and Equipment, Total											$ 5,555,000	$ 12,132,000
Finance Lease, Principal Payments											13,000	13,000
Long-term Debt, Gross											60,554,000		$ 52,187,000
Debt Instrument, Unused Borrowing Capacity, Amount											4,900,000		28,700,000
Cash Collateral for Borrowed Securities											4,300,000		5,400,000
Chailease Finance Co, Ltd. [Member] | Promissory Note [Member]
Long-term Debt, Gross											$ 361,000		$ 1,941,000
Debt Instrument, Interest Rate, Stated Percentage											3.50%		3.50%
Chailease Finance Co, Ltd. [Member] | Prime World International Holdings, Ltd. (“Prime World”) [Member] | Promissory Note [Member]
Finance Lease, Principal Payments				$ 5,500,000
Chailease Finance Co, Ltd. [Member] | Prime World International Holdings, Ltd. (“Prime World”) [Member] | Second Sales Contract [Member]
Finance Lease, Principal Payments					$ 159,027,448
Long-term Debt, Gross																					$ 700,000
Chailease Finance Co, Ltd. [Member] | Prime World International Holdings, Ltd. (“Prime World”) [Member] | Second Sales Contract [Member] | Promissory Note [Member]
Long-term Debt, Gross																						$ 400,000
Chailease Finance Co, Ltd. [Member] | Prime World International Holdings, Ltd. (“Prime World”) [Member] | Forecast [Member]
Payments to Acquire Property, Plant, and Equipment, Total	$ 800,000
Paycheck Protection Program, CARES Act [Member]
Proceeds from Issuance of Long-term Debt, Total						$ 6,230,000
Long-term Debt, Gross											$ 0		$ 6,229,000
Debt Instrument, Interest Rate, Stated Percentage											1.00%		1.00%
Revolving Credit Facility [Member] | The NT$100M Credit Line [Member] | Prime World International Holdings, Ltd. (“Prime World”) [Member]
Line of Credit Facility, Maximum Borrowing Capacity																$ 100,000,000
Revolving Credit Facility [Member] | Truist Bank [Member]
Line of Credit Facility, Maximum Borrowing Capacity		$ 20,000,000					$ 20,000,000													$ 25,000,000
Debt Instrument, Unused Borrowing Capacity, Fee, Percentage							0.30%
Fixed Charge Cover Ratio, Minimum Threshold							1.5
Line of Credit Facility, Percentage of Maximum Borrowing Capacity, Threshold for Financial Covenants							75.00%
Debt Instrument, LIBOR Floor		0.75%
Long-term Line of Credit, Total											$ 19,300,000
Revolving Credit Facility [Member] | Truist Bank [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Basis Spread on Variable Rate		1.50%
Revolving Credit Facility [Member] | Taishin International Bank [Member] | The NT$100M Credit Line [Member] | Prime World International Holdings, Ltd. (“Prime World”) [Member]
Line of Credit Facility, Maximum Borrowing Capacity			$ 3,440,000
Revolving Credit Facility [Member] | Taishin International Bank [Member] | The US $1M Credit Line [Member] | Prime World International Holdings, Ltd. (“Prime World”) [Member]
Line of Credit Facility, Maximum Borrowing Capacity			$ 1,000,000
Revolving Credit Facility [Member] | Taishin International Bank in Taiwan [Member] | The NT$100M Credit Line [Member] | Prime World International Holdings, Ltd. (“Prime World”) [Member]
Debt Instrument, Interest Rate, Stated Percentage			2.15%													2.15%
Revolving Credit Facility [Member] | Taishin International Bank in Taiwan [Member] | The NT$100M Credit Line [Member] | Prime World International Holdings, Ltd. (“Prime World”) [Member] | Minimum [Member]
Debt Instrument, Term of Draw (Day)			90 days
Revolving Credit Facility [Member] | Taishin International Bank in Taiwan [Member] | The NT$100M Credit Line [Member] | Prime World International Holdings, Ltd. (“Prime World”) [Member] | Maximum [Member]
Debt Instrument, Term of Draw (Day)			120 days
Revolving Credit Facility [Member] | China Construction Bank Co., Ltd. [Member] | China Merchants Credit Line [Member] | Global Technology, Inc. [Member]
Line of Credit Facility, Maximum Borrowing Capacity														$ 8,900,000	¥ 60,000,000				¥ 60,000,000
Long-term Line of Credit, Total											0
Debt Instrument, Term (Month)										12 months
Bank Acceptances Executed											2,600,000
Revolving Credit Facility [Member] | China Merchants Bank Co, Ltd [Member]
Line of Credit Facility, Maximum Borrowing Capacity											8,917,000		$ 8,917,000
Long-term Debt, Gross											$ 0		$ 2,299,000
Debt Instrument, Interest Rate, Stated Percentage											4.50%		4.50%
Revolving Credit Facility [Member] | China Merchants Bank Co, Ltd [Member] | China Merchants Credit Line [Member] | Global Technology, Inc. [Member]
Line of Credit Facility, Maximum Borrowing Capacity										$ 8,900,000
Revolving Credit Facility [Member] | SPD Bank [Member]
Line of Credit Facility, Maximum Borrowing Capacity											$ 25,449,000		$ 25,449,000
Long-term Debt, Gross											$ 17,924,000		$ 11,603,000
Revolving Credit Facility [Member] | SPD Bank [Member] | Minimum [Member]
Debt Instrument, Interest Rate, Stated Percentage											3.01%		3.01%
Revolving Credit Facility [Member] | SPD Bank [Member] | Maximum [Member]
Debt Instrument, Interest Rate, Stated Percentage											4.57%		4.57%
Revolving Credit Facility [Member] | SPD Bank [Member] | The SPD Credit Line [Member] | Global Technology, Inc. [Member]
Line of Credit Facility, Maximum Borrowing Capacity									$ 25,400,000									¥ 180,000,000
Long-term Line of Credit, Total												17,900,000
Debt Instrument, Term (Month)									5 years
Bank Acceptances Executed												$ 3,900,000
Revolving Credit Facility [Member] | China Zheshang Bank Co., Ltd [Member] | The ¥100M Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity											$ 14,125,000
Long-term Debt, Gross											$ 14,892,000		$ 0
Debt Instrument, Interest Rate, Stated Percentage											3.50%
Revolving Credit Facility [Member] | China Zheshang Bank Co., Ltd [Member] | The ¥100M Credit Facility [Member] | Global Technology, Inc. [Member]
Line of Credit Facility, Maximum Borrowing Capacity								$ 14,100,000			$ 14,900,000						¥ 100,000,000
Debt Instrument, Term (Month)								18 months
Bank Acceptances Executed											0
Revolving Credit Facility [Member] | China Zheshang Bank Co., Ltd [Member] | The ¥50M Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity											7,167,000
Long-term Debt, Gross											$ 7,401,000		$ 7,510,000
Debt Instrument, Interest Rate, Stated Percentage											5.70%
Revolving Credit Facility [Member] | China Zheshang Bank Co., Ltd [Member] | The ¥50M Credit Facility [Member] | Global Technology, Inc. [Member]
Line of Credit Facility, Maximum Borrowing Capacity								$ 7,100,000									¥ 50,000,000
Long-term Line of Credit, Total											$ 7,400,000
Debt Instrument, Term (Month)								3 years

Note 11 - Notes Payable and L_4

Note 11 - Notes Payable and Long-term Debt - Schedule of Notes Payable and Long-term Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Long-term debt	$ 60,554	$ 52,187
Less debt issuance costs, net	29	18
Grand total	60,525	52,169
Less current portion	41,254	38,265
Non-current portion	19,271	13,904
Bank acceptance notes issued to vendors with a zero percent interest rate	6,481	15,860
2022	41,254
2023	19,271
Total outstanding	60,525	52,169
Chailease Finance Co, Ltd. [Member] | Promissory Note [Member]
Long-term debt	361	1,941
Chailease Finance Co, Ltd. [Member] | Promissory Note 2 [Member]
Long-term debt	676	2,149
Paycheck Protection Program, CARES Act [Member]
Long-term debt	0	6,229
Truist Bank [Member] | Revolving Credit Facility [Member] | Third Amendment to Loan Agreement with BB and T [Member]
Long-term debt	19,300	18,700
Taishin International Bank [Member] | Revolving Credit Facility [Member] | Credit Facility [Member]
Long-term debt	0	1,756
China Merchants Bank Co, Ltd [Member] | Revolving Credit Facility [Member]
Long-term debt	0	2,299
SPD Bank [Member] | Revolving Credit Facility [Member]
Long-term debt	17,924	11,603
China Zheshang Bank Co., Ltd [Member] | Revolving Credit Facility [Member] | The ¥100M Credit Facility [Member]
Long-term debt	14,892	0
China Zheshang Bank Co., Ltd [Member] | Revolving Credit Facility [Member] | The ¥50M Credit Facility [Member]
Long-term debt	$ 7,401	$ 7,510

Note 11 - Notes Payable and L_5

Note 11 - Notes Payable and Long-term Debt - Schedule of Notes Payable and Long-term Debt (Details) (Parentheticals) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020	Apr. 05, 2021	Sep. 30, 2019	Mar. 05, 2019
Chailease Finance Co, Ltd. [Member] | Promissory Note [Member]
Long-term debt, interest	3.50%	3.50%
Long-term debt, maturity date	Jan. 21, 2022	Jan. 21, 2022
Chailease Finance Co, Ltd. [Member] | Promissory Note 2 [Member]
Long-term debt, interest	3.10%	3.10%
Long-term debt, maturity date	Jan. 21, 2022	Jan. 21, 2022
Paycheck Protection Program, CARES Act [Member]
Long-term debt, interest	1.00%	1.00%
Long-term debt, maturity date	Apr. 16, 2022	Apr. 16, 2022
Truist Bank [Member] | Revolving Credit Facility [Member]
Long-term debt, maximum			$ 20,000,000	$ 20,000,000	$ 25,000,000
Truist Bank [Member] | Revolving Credit Facility [Member] | Third Amendment to Loan Agreement with BB and T [Member]
Long-term debt, maximum	$ 20,000,000	$ 20,000,000
Long-term debt, interest	2.25%	2.25%
Long-term debt, maturity date	Oct. 15, 2022	Oct. 15, 2022
Taishin International Bank [Member] | Revolving Credit Facility [Member] | Credit Facility [Member]
Long-term debt, maximum	$ 3,436,000	$ 3,436,000
Long-term debt, interest	2.20%	2.20%
Long-term debt, maturity date	Apr. 14, 2021	Apr. 14, 2021
China Merchants Bank Co, Ltd [Member] | Revolving Credit Facility [Member]
Long-term debt, maximum	$ 8,917,000	$ 8,917,000
Long-term debt, interest	4.50%	4.50%
Long-term debt, maturity date	Oct. 14, 2020	Oct. 14, 2020
SPD Bank [Member] | Revolving Credit Facility [Member]
Long-term debt, maximum	$ 25,449,000	$ 25,449,000
Long-term debt, maturity date	May 24, 2024	May 24, 2024
SPD Bank [Member] | Revolving Credit Facility [Member] | Minimum [Member]
Long-term debt, interest	3.01%	3.01%
SPD Bank [Member] | Revolving Credit Facility [Member] | Maximum [Member]
Long-term debt, interest	4.57%	4.57%
China Zheshang Bank Co., Ltd [Member] | Revolving Credit Facility [Member] | The ¥100M Credit Facility [Member]
Long-term debt, maximum	$ 14,125,000
Long-term debt, interest	3.50%
Long-term debt, maturity date	Jan. 5, 2024
China Zheshang Bank Co., Ltd [Member] | Revolving Credit Facility [Member] | The ¥50M Credit Facility [Member]
Long-term debt, maximum	$ 7,167,000
Long-term debt, interest	5.70%
Long-term debt, maturity date	Jun. 20, 2022

Note 12 - Convertible Senior _3

Note 12 - Convertible Senior Notes (Details Textual) - USD ($)	Mar. 05, 2019	Sep. 30, 2021	Dec. 31, 2020
Truist Bank [Member] | CapEx Loan and Term Loan [Member]
Repayments of Long-term Debt, Total	$ 37,800,000
The 5% Convertible Senior Notes Due 2024 [Member]
Debt Instrument, Face Amount	$ 80,500,000	$ 80,500,000	$ 80,500,000
Debt Instrument, Interest Rate, Stated Percentage	5.00%
Proceeds from Convertible Debt	$ 76,400,000
Debt Conversion, Converted Instrument, Shares Issued (in shares)	56.9801
Debt Conversion, Converted Instrument, Amount	$ 1,000
Debt Instrument, Convertible, Conversion Price (in dollars per share)	$ 17.55
Debt Instrument, Convertible, Conversion Price Premium, Percentage	30.00%
Share Price (in dollars per share)	$ 13.50
Debt Instrument, Convertible, Threshold Percentage of Stock Price Trigger	130.00%
Debt Instrument, Convertible, Threshold Trading Days	20
Debt Instrument, Convertible, Threshold Consecutive Trading Days	30
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed	100.00%
Debt Issuance Costs, Gross	$ 4,100,000

Note 12 - Convertible Senior _4

Note 12 - Convertible Senior Notes - Schedule of Carrying Value of Convertible Senior Notes (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Mar. 05, 2019
Net carrying amount	$ 78,472	$ 77,854
The 5% Convertible Senior Notes Due 2024 [Member]
Principal	80,500	80,500	$ 80,500
Unamortized debt issuance costs	(2,028)	(2,646)
Net carrying amount	$ 78,472	$ 77,854

Note 12 - Convertible Senior _5

Note 12 - Convertible Senior Notes - Schedule of Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Amortization of debt issuance costs			$ 650	$ 673
The 5% Convertible Senior Notes Due 2024 [Member]
Contractual interest expense	$ 1,006	$ 1,006	3,018	3,018
Amortization of debt issuance costs	208	209	618	623
Total interest cost	$ 1,214	$ 1,215	$ 3,636	$ 3,641
Effective interest rate	5.10%	5.10%	5.10%	5.10%

Note 13 - Accrued Liabilities -

Note 13 - Accrued Liabilities - Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Accrued payroll	$ 8,348	$ 10,517
Accrued employee benefits	3,247	3,057
Accrued state and local taxes	1,390	251
Accrued interest	351	1,256
Advance payments	480	303
Accrued product warranty	272	703
Accrued commission expenses	903	974
Accrued professional fees	293	377
Accrued shipping and tariff expenses	235	526
Accrued other	685	547
Total accrued liabilities	$ 16,204	$ 18,511

Note 14 - Other Income and Ex_3

Note 14 - Other Income and Expense - Other Income and Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Foreign exchange transaction gain (loss)	$ (1)	$ (271)	$ 217	$ (18)
Government subsidy income	826	847	980	1,828
Other non-operating gain	171	296	205	301
Loan forgiveness	0	0	6,229	0
Gain (loss) on disposal of assets	2	(6)	(3)	(15)
Total other income, net	$ 998	$ 866	$ 7,628	$ 2,096

Note 15 - Share-based Compens_3

Note 15 - Share-based Compensation (Details Textual) - USD ($) $ in Thousands	1 Months Ended	9 Months Ended
	Jun. 30, 2021	Sep. 30, 2021
Share-based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount		$ 0
Share-based Payment Arrangement, Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)		4 years
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)		10 years
Share-based Payment Arrangement, Option [Member] | Exercisable on the First Anniversary Date Following the Date of Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage		25.00%
Share-based Payment Arrangement, Option [Member] | Exercisable on Semi-annual Basis [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage		12.50%
Restricted Stock Awards and Restricted Stock Units [Member]
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total		$ 24,500
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)		2 years 7 months 24 days
Performance Shares [Member] | Minimum [Member]
SharebasedCompensationArrangementBySharebasedPaymentAwardPerformanceAwardValuePercentageOfBasedAmount	0.00%
Performance Shares [Member] | Maximum [Member]
SharebasedCompensationArrangementBySharebasedPaymentAwardPerformanceAwardValuePercentageOfBasedAmount	200.00%
Performance Shares [Member] | Vesting on the Third Anniversary [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	100.00%

Note 15 - Share-based Compens_4

Note 15 - Share-based Compensation - Option Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Outstanding, number of shares (in shares)	276
Outstanding, weighted average exercise price (in dollars per share)	$ 10.29
Outstanding, weighted average fair value (in dollars per share)	$ 5.44	$ 5.41
Outstanding, weighted average remaining contractual life (Year)	1 year 11 months 8 days	2 years 8 months 1 day
Outstanding, aggregate intrinsic value	$ 6	$ 54
Exercised, number of shares (in shares)	(2)
Exercised, weighted average exercise price (in dollars per share)	$ 6
Exercised, weighted average share price on date of exercise (in dollars per share)
Exercised, aggregate intrinsic value	$ 7
Forfeited (in shares)	(4)
Forfeited, weighted average exercise price (in dollars per share)	$ 10.46
Forfeited, weighted average fair value (in dollars per share)	$ 5.64
Forfeited, aggregate intrinsic value	$ 1
Outstanding, number of shares (in shares)	270	276
Outstanding, weighted average exercise price (in dollars per share)	$ 10.32	$ 10.29
Exercisable, number of shares (in shares)	270
Exercisable, weighted average exercise price (in dollars per share)	$ 10.32
Exercisable, weighted average remaining contractual life (Year)	1 year 11 months 8 days
Exercisable, aggregate intrinsic value	$ 6
Vested and expected to vest, number of shares (in shares)	270
Vested and expected to vest, weighted average exercise price (in dollars per share)	$ 10.33
Vested and expected to vest, weighted average remaining contractual life (Year)	1 year 11 months 8 days
Vested and expected to vest, aggregate intrinsic value	$ 6

Note 15 - Share-based Compens_5

Note 15 - Share-based Compensation - Restricted Stock Unit/Awards Activity (Details) - Restricted Stock Units (RSUs) [Member] $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2021USD ($)$ / sharesshares
Outstanding, number of shares (in shares) | shares	1,325
Outstanding, weighted average fair value (in dollars per share)	$ 14.97
Outstanding, aggregate intrinsic value | $	$ 11,279
Granted, number of shares (in shares) | shares	1,732
Granted, weighted average fair value (in dollars per share)	$ 10.12
Granted, aggregate intrinsic value | $	$ 16,007
Released, number of shares (in shares) | shares	(590)
Released, weighted average share price on date of release (in dollars per share)	$ 8.59
Released, weighted average fair value (in dollars per share)	$ 15.87
Released, aggregate intrinsic value | $	$ 5,069
Cancelled/Forfeited, number of shares (in shares) | shares	(73)
Cancelled/Forfeited, weighted average fair value (in dollars per share)	$ 13.05
Cancelled/Forfeited, aggregate intrinsic value | $	$ 527
Outstanding, number of shares (in shares) | shares	2,394
Outstanding, weighted average fair value (in dollars per share)	$ 11.30
Outstanding, aggregate intrinsic value | $	$ 17,189
Vested and expected to vest, number of shares (in shares) | shares	2,394
Vested and expected to vest, weighted average fair value (in dollars per share)	$ 11.30
Vested and expected to vest, aggregate intrinsic value | $	$ 17,189

Note 15 - Share-based Compens_6

Note 15 - Share-based Compensation - Share-based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Total share-based compensation expense	$ 3,129	$ 3,265	$ 8,922	$ 9,804
Cost of Sales [Member]
Total share-based compensation expense	222	230	689	712
Research and Development Expense [Member]
Total share-based compensation expense	489	706	1,682	2,098
Selling and Marketing Expense [Member]
Total share-based compensation expense	272	298	820	884
General and Administrative Expense [Member]
Total share-based compensation expense	$ 2,146	$ 2,031	$ 5,731	$ 6,110

Note 16 - Income Taxes (Details

Note 16 - Income Taxes (Details Textual)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Effective Income Tax Rate Reconciliation, Percent, Total	0.00%	30.69%	0.00%	19.15%
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	21.00%	21.00%	21.00%

Note 17 - Geographic Informat_3

Note 17 - Geographic Information (Details Textual)	9 Months Ended
	Sep. 30, 2021
Number of Reportable Segments	1

Note 17- Geographic Information

Note 17- Geographic Information - Revenue Information by Geographic Region (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenue, net	$ 53,267	$ 76,608	$ 157,157	$ 182,298
UNITED STATES
Revenue, net	4,547	4,887	11,451	13,383
TAIWAN, PROVINCE OF CHINA
Revenue, net	19,562	45,821	75,282	105,196
CHINA
Revenue, net	$ 29,158	$ 25,900	$ 70,424	$ 63,719

Note 17 - Geographic Informat_4

Note 17 - Geographic Information - Asset Information by Geographic Region (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Long-lived assets	$ 259,461	$ 270,654
UNITED STATES
Long-lived assets	87,241	90,999
TAIWAN, PROVINCE OF CHINA
Long-lived assets	65,394	71,080
CHINA
Long-lived assets	$ 106,826	$ 108,575

Note 19 - Subsequent Events (De

Note 19 - Subsequent Events (Details Textual) - USD ($) $ in Thousands	1 Months Ended	9 Months Ended
	Oct. 31, 2021	Sep. 30, 2021	Sep. 30, 2020
Repayments of Lines of Credit		$ 86,922	$ 67,430
Revolving Credit Facility [Member] | Truist Bank [Member] | Subsequent Event [Member]
Repayments of Lines of Credit	$ 19,300