Cover - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 19, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K/A
Amendment No. 1	true
Amendment Description	to correct Items 11 and 13
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Dec. 31, 2020
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2020
Current Fiscal Year End Date	--12-31
Entity File Number	001-36083
Entity Registrant Name	Applied Optoelectronics, Inc.
Entity Central Index Key	0001158114
Entity Tax Identification Number	76-0533927
Entity Incorporation, State or Country Code	DE
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 Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
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 Public Float			$ 187,049,677
Entity Common Stock, Shares Outstanding		26,699,547
ICFR Auditor Attestation Flag	true