Note 18 - Contingencies	6 Months Ended
Jun. 30, 2021
Notes to Financial Statements
Commitments and Contingencies Disclosure [Text Block]	*Note 18.* Contingencies Litigation** Overview From time to time, the Company may be subject to legal proceedings and litigation arising in the ordinary course of business, including, but not limited to, inquiries, investigations, audits and other regulatory proceedings, such as described below. The Company records a loss provision when it believes it is both probable that a liability has been incurred and the amount can be reasonably estimated. Unless otherwise disclosed, the Company is unable to estimate the possible loss or range of loss for the legal proceeding described below. Except for the lawsuits described below, the Company believes that there are no claims or actions pending or threatened against it, the ultimate disposition of which would have a material adverse effect on it. Class Action and Shareholder Derivative Litigation On August 7, 2018, a derivative lawsuit was filed in the United States District Court for the Southern District of Texas styled Lei Jin, derivatively on behalf ofApplied 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-cv-02713 alleging breaches of fiduciary duties, unjust enrichment, and violations of Section 14(a) of the Exchange Act based on similar factual allegations as in the securities class action captioned Mona Abouzied v. Applied Optoelectronics, Inc., Chih-Hsiang (Thompson) Lin, and Stefan J. Murry, et al., Case No. 4:17-cv-02399, which had been previously filed against the Company and was dismissed following a settlement in 2020. On December 18, 2018, a second derivative complaint was filed styled 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-cv-4751 alleging the same causes of actions as the Jin complaint and additional factual allegations regarding our announcement on September 28, 2018 that we had “identified an issue with a small percentage of 25G lasers within a specific customer environment.” On January 11, 2019, the court consolidated these two derivative actions, and on January 15, 2019, the court entered an order staying the actions pending the resolution of the securities class actions. On June 24, 2020, the plaintiffs filed a notice that the stay of proceedings had been terminated, and on July 2, 2020, the parties filed a Joint Stipulation and Proposed Scheduling Order. The court 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. By agreement of the parties, the Court subsequently extended the deadline for Defendants to file and serve their response or responsive pleading to December 2, 2020. On December 2, 2020, Defendants filed their motion to dismiss the consolidated derivative complaint. On December 7, 2020, Plaintiffs filed a notice alerting the Court that they were intending to file an amended complaint, which was subsequently filed by Plaintiffs on January 13, 2021. Defendants filed a motion to dismiss all claims on March 1, 2021. Plaintiffs’ response deadline is May 3, 2021. On June 25, 2021, the parties filed a stipulation indicating that they had reached a settlement-in-principle of the action. On June 28, 2021, the Court stayed all deadlines in the action for 30 days to allow the parties to finalize the settlement. The deadline was extended to August 13, 2021. At this stage, we are not yet able to determine the likelihood of loss, if any, arising from this matter.

Note 18 - Contingencies

6 Months Ended

Jun. 30, 2021

Commitments and Contingencies Disclosure [Text Block]

Note 18. Contingencies

Litigation

Overview

From time to time, the Company may be subject to legal proceedings and litigation arising in the ordinary course of business, including, but not limited to, inquiries, investigations, audits and other regulatory proceedings, such as described below. The Company records a loss provision when it believes it is both probable that a liability has been incurred and the amount can be reasonably estimated. Unless otherwise disclosed, the Company is unable to estimate the possible loss or range of loss for the legal proceeding described below.

Except for the lawsuits described below, the Company believes that there are no claims or actions pending or threatened against it, the ultimate disposition of which would have a material adverse effect on it.

Class Action and Shareholder Derivative Litigation

On August 7, 2018, a derivative lawsuit was filed in the United States District Court for the Southern District of Texas styled Lei Jin, derivatively on behalf ofApplied 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-cv-02713 alleging breaches of fiduciary duties, unjust enrichment, and violations of Section 14(a) of the Exchange Act based on similar factual allegations as in the securities class action captioned Mona Abouzied v. Applied Optoelectronics, Inc., Chih-Hsiang (Thompson) Lin, and Stefan J. Murry, et al., Case No. 4:17-cv-02399, which had been previously filed against the Company and was dismissed following a settlement in 2020. On December 18, 2018, a second derivative complaint was filed styled 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-cv-4751 alleging the same causes of actions as the Jin complaint and additional factual allegations regarding our announcement on September 28, 2018 that we had “identified an issue with a small percentage of 25G lasers within a specific customer environment.” On January 11, 2019, the court consolidated these two derivative actions, and on January 15, 2019, the court entered an order staying the actions pending the resolution of the securities class actions. On June 24, 2020, the plaintiffs filed a notice that the stay of proceedings had been terminated, and on July 2, 2020, the parties filed a Joint Stipulation and Proposed Scheduling Order. The court 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. By agreement of the parties, the Court subsequently extended the deadline for Defendants to file and serve their response or responsive pleading to December 2, 2020. On December 2, 2020, Defendants filed their motion to dismiss the consolidated derivative complaint. On December 7, 2020, Plaintiffs filed a notice alerting the Court that they were intending to file an amended complaint, which was subsequently filed by Plaintiffs on January 13, 2021. Defendants filed a motion to dismiss all claims on March 1, 2021. Plaintiffs’ response deadline is May 3, 2021. On June 25, 2021, the parties filed a stipulation indicating that they had reached a settlement-in-principle of the action. On June 28, 2021, the Court stayed all deadlines in the action for 30 days to allow the parties to finalize the settlement. The deadline was extended to August 13, 2021. At this stage, we are not yet able to determine the likelihood of loss, if any, arising from this matter.