_________________________________

_________________________________

(MARK ONE)

x ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended June 30, 2018

OR

o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

FOR THE TRANSITION PERIOD FROM              TO             

Commission file number 001-34717

__________________________

(Exact name of Registrant as Specified in its Charter)

Clarendon House, 2 Church Street

Hamilton HM 11, Bermuda

(Address of Principal Registered

Offices including Zip Code)

(408) 830-9742

(Registrant's Telephone Number, Including Area Code)

__________________________________________

Securities registered pursuant to Section 12(b) of the Act:

Securities registered pursuant to Section 12(g) of the Act:

None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.    Yes   o     No   x

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.    Yes   o     No   x

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months, (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes   x     No   o

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).    Yes   x    No   o

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of registrant's knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K, or any amendment to this Form 10-K.    x

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer or smaller reporting company. See definitions of "large accelerated filer," "accelerated filer" and "smaller reporting company" in Rule 12b-2 of the Exchange Act. (Check one):

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. o

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).    Yes   o     No   x

The aggregate market value of the voting shares held by non-affiliates of the registrant as of December 29, 2017 was approximately $317 million based on the closing price of the registrant's common share as reported on the NASDAQ Global Select Market on December 29, 2017 (the last business day of the registrant's most recently completed second fiscal quarter). The common shares of the registrant held by each executive officer and director and certain affiliated shareholders who beneficially owned 10% or more of the outstanding common stock of the registrant have been excluded in such calculation as such persons and entities may be deemed to be affiliates of the registrant. This determination of affiliate status is not necessarily a conclusive determination for other purposes.

There were 23,862,847 shares of the registrant's common shares outstanding as of July 31, 2018 .

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the registrant's Proxy Statement for the registrant's 2018 Annual General Meeting of Shareholders are incorporated by reference into Part III of this Form 10-K to the extent stated herein. The Definitive Proxy Statement is expected to be filed within 120 days of the registrant's fiscal year ended June 30, 2018 .

Alpha and Omega Semiconductor Limited

Form 10-K

For the Year Ended June 30, 2018

TABLE OF CONTENTS

(This page intentionally left blank.)

PART I

Forward Looking Statements

This Annual Report on Form 10-K and the documents incorporated herein by reference contain forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, which are subject to the "safe harbor" created by those sections. Forward-looking statements are based on our management's beliefs and assumptions and on information currently available to our management. In some cases, you can identify forward-looking statements by terms such as "may," "will," "should," "could," "intend," "would," "expect," "plan," "anticipate," "believe," "estimate," "project," "predict," "potential" and similar expressions intended to identify forward-looking statements. These statements involve known and unknown risks, uncertainties and other factors, which may cause our actual results, performance, time frames or achievements to be materially different from any future results, performance, time frames or achievements expressed or implied by the forward-looking statements. We discuss many of these risks, uncertainties and other factors in this Annual Report on Form 10-K in greater detail in Item 1A."Risk Factors." Given these risks, uncertainties and other factors, you should not place undue reliance on these forward-looking statements. Also, these forward-looking statements represent our estimates and assumptions only as of the date of this filing. You should read this Annual Report on Form 10-K in its entirety and with the understanding that our actual future results may be materially different from what we expect. We hereby qualify our forward-looking statements by these cautionary statements. Except as required by law, we assume no obligation to update these forward-looking statements publicly, or to update the reasons actual results could differ materially from those anticipated in these forward-looking statements, even if new information becomes available in the future.

Overview    

We are a designer, developer and global supplier of a broad portfolio of power semiconductors. Our portfolio of power semiconductors includes approximately 1,900 products, and has grown significantly with the introduction of 200 new products during the fiscal year ended June 30, 2018 , and over 80 and 90 new products in each of the fiscal years ended June 30, 2017 and 2016 , respectively. Our teams of scientists and engineers have developed extensive intellectual properties and technical knowledge that encompass major aspects of power semiconductors, which we believe enable us to introduce and develop innovative products to address the increasingly complex power requirements of advanced electronics. We have an extensive patent portfolio that consists of 722 patents and 108 patent applications in the United States as of June 30, 2018 . We differentiate ourselves by integrating our expertise in technology, design, manufacturing capability and advanced packaging to optimize product performance and cost. Our portfolio of products targets high-volume applications, including personal computers, flat panel TVs, smart phones, battery packs, quick chargers, home appliances, consumer and industrial motor controls and power supplies for TVs, computers, servers and telecommunications equipment.

During the fiscal year ended June 30, 2018 , we continued our diversification strategy by developing new silicon and packaging platforms to expand our serviceable available market, or SAM and offer higher performance products. Our metal-oxide-semiconductor field-effect transistors, or MOSFET, portfolio expanded significantly across a full range of voltage applications. We also developed new technologies and products designed to penetrate into markets beyond our MOSFET computing base, including the consumer, communications and industrial markets as well as power IC for the next generation computing applications.

Our business model leverages global resources, including research and development and manufacturing in the United States and Asia. Our sales and technical support teams are localized in several growing markets primarily in Asia. We operate a 8-inch wafer fabrication facility located in Hillsboro, Oregon, or the Oregon fab, which enables us to accelerate proprietary technology development, new product introduction and improve our financial performance. To meet the market demand for the more mature high volume products, we also utilize the wafer manufacturing capacity of selected third party foundries. For assembly and test, we primarily rely upon our in-house facilities in China. In addition, we utilize subcontracting partners for industry standard packages. We believe our in-house packaging and testing capability provides us with a competitive advantage in proprietary packaging technology, product quality, costs and sales cycle time.

On March 29, 2016, we entered into a joint venture contract (the "JV Agreement") with two investment funds affiliated with the municipalities of Chongqing (the "Chongqing Funds"), pursuant to which we and Chongqing Funds form a joint venture, (the "JV Company"), for the purpose of constructing a power semiconductor packaging, testing and wafer fabrication facility in the Liangjiang New Area of Chongqing, China (the "JV Transaction"). The total initial capitalization of the JV Company is $330.0 million (the "Initial Capitalization").  As of June 30, 2018, we own 51%, and the Chongqing Funds own 49%, of the equity interest in the JV Company. The JV Company substantially completed its assembly and testing and 12-inch

wafer fab facilities during the quarter ended June 30, 2018. We expect to commence limited mass production for assembly and testing in the second half of calendar year 2018, and trial production for the 12-inch wafer fabrication facility toward the end of calendar year 2018.

In September 2017, we entered into a license agreement with STMicroelectronics International N.V. ("STMicro"), which allows us to develop and market certain digital power multi-phase controller products and enter into new markets, primarily in server and telecommunications. We are in the process of developing this new digital power business. We hired approximately two-thirds of the team that we plan to build. The team has been engaging with potential customers in product designs.

We were incorporated in Bermuda on September 27, 2000 as an exempted limited liability company. The address of our registered office is Clarendon House, 2 Church Street, Hamilton HM 11, Bermuda. Our agent for service of process in the U.S. for the purpose of our securities filings is our Chief Executive Officer, Mike F. Chang, c/o Alpha and Omega Semiconductor Incorporated, 475 Oakmead Parkway, Sunnyvale, CA 94085. Telephone number of our agent is (408) 830-9742.

We have incorporated various wholly-owned subsidiaries in different jurisdictions, and a subsidiary (the JV Company) in which we have a controlling interest. Please refer to Exhibit 21.1 for a complete list of our subsidiaries.

Our industry

Semiconductors are electronic devices that perform a variety of functions, such as converting or controlling signals, processing data and delivering or managing power. With advances in semiconductor technology, the functionality and performance of semiconductors have generally increased over time, while size and cost have generally decreased. These advances have led to a proliferation of more complex semiconductors being used in a wide variety of consumer, computing, communications and industrial markets and have contributed to the growth of the semiconductor industry.

Analog semiconductors

The semiconductor industry is segmented into analog and digital. Analog semiconductors process light, sound, motion, radio waves and electrical currents and voltages. In contrast, digital semiconductors process binary signals represented by a sequence of ones and zeros.

As a result of these fundamental differences, the analog semiconductor industry is distinct from the digital semiconductor industry in terms of the complexity of design and the length of product cycle. Improper interactions between analog circuit elements can potentially render an electronic system inoperable. Experienced engineers engaged in the design process are necessary because computer-aided design cannot fully model the behavior of analog circuitry. Therefore, experienced analog engineers with requisite knowledge are in great demand but short supply worldwide. In addition, analog semiconductors tend to have a longer product life cycle because original design manufacturers, or ODMs and original equipment manufacturers, or OEMs typically design the analog portions of a system to span multiple generations of their products. Once designed into an application, the analog portion is rarely modified because even a slight change to the analog portion can cause unexpected interactions with other components, resulting in system instability.

Power semiconductors

Power semiconductors are a subset of the analog semiconductor sector with their own set of characteristics unique to power architecture and function. Power semiconductors transfer, manage and switch electricity to deliver the appropriate amount of voltage or current to a broad range of electronic systems and also protect electronic systems from damage resulting from excessive or inadvertent electrical charges.

Power semiconductors can be either discrete devices, which typically comprise only a few transistors or diodes, or ICs, which incorporate a greater number of transistors.  The function of power discrete devices is power delivery by switching, transferring or converting electricity.  Power transistors comprise the largest segment of the power discrete device market. Power ICs, sometimes referred to as power management ICs, perform power delivery and power management functions, such as controlling and regulating voltage and current and controlling power discrete devices.

The growth of the power semiconductor market in recent years has several key drivers. The proliferation of computer and consumer electronics, such as notebooks, tablets, smart phones, flat panel displays and portable media players created the need for sophisticated power management to improve power efficiency and extend battery life. The evolution of these products is characterized by increased functionality, thinner or smaller form factors and decreasing prices. Our Power IC and low voltage (5V-40V) MOSFET products address this market. In the area of AC-DC power supplies for electronic equipment, data centers

and servers, the market is characterized by a continuous demand for energy conservation through higher efficiency, which is driving the need for our medium voltage (40V-400V) and high voltage (500V-1000V) MOSFET products. The increased application of power semiconductors to control motors in white goods and industrial applications, is driving demand for Insulated Gate Bipolar Transistors, or IGBTs. IGBTs are also being used in renewable energy and automotive applications.

The evolution toward smaller form factors and complex power requirements in the low voltage areas has driven further integration in power semiconductors, resulting in power ICs that incorporate the functionalities of both power management and power delivery in a single device. Power ICs can be implemented by incorporating all necessary power functions either on one piece of silicon or multiple silicon chips encapsulated into a single device. Additionally, the advancement in semiconductor packaging technology enables increased power density and shrinking form factors.

Power semiconductor suppliers develop and manufacture their products using various approaches which tend to fall across a wide spectrum of balancing cost savings with proprietary technology advantages. At one end of the spectrum are integrated design manufacturers, or IDMs, which own and operate the equipment used in the manufacturing process and design and manufacture products at their in-house facilities. IDMs exercise full control over the implementation of process technologies and have maximum flexibility in setting priorities for their production and delivery schedules. At the other end of the spectrum are completely-outsourced fabless semiconductor companies, which rely entirely on off-the-shelf technologies and processes provided by their manufacturing partners. These companies seek to reduce or eliminate fixed costs by outsourcing both product manufacturing and development of process technologies to third parties. Our model seeks to achieve the best balance between technological advancement and cost effectiveness by using a dedicated in-house technology laboratory to drive rapid new product developments, while utilizing third-party foundry capacity for mature products. This is particularly important in the development of power semiconductor products due to the unique nature of their technology. While digital technologies are highly standardized in leading foundries, power semiconductor technologies tend to be more unique as they seek to accommodate a wider range of voltage applications. Accordingly, third-party foundries, which are primarily designed and established for digital technologies, can be limited when it comes to the development of new power semiconductor technologies.

Our strategies

Our strategy is to advance our position as a designer, developer and global supplier of a broad portfolio of power semiconductors. To accomplish this, we have adopted a strategy that allows us to accelerate the development of our proprietary technology at our Oregon fab, bring new products to market faster, and improve our financial performance in the long run. This model also provides quicker response to our customer demands, enhances relationships with strategic customers, and provides flexibility in capacity management and geographic diversification of our wafer supply chain. Our in-house manufacturing capability allows us to retain a higher level of control over the development and application of our proprietary process technology, thereby reducing certain operational risks and costs associated with utilizing third-party foundries. In addition, we expect to expand our manufacturing capacity through the JV Transaction, which we believe will also allow us to expand and diversify our markets in China, as well as to accelerate the development of our proprietary process technology through our Chongqing manufacturing facilities.

In addition to our products targeting the PC market, we execute our strategies of diversifying our portfolio of products and expanding into other market segments, including the consumer, communications, power supplies and industrial market segments, and improving gross margin and profit by implementing cost control measures. We have been making progress in reducing our reliance on the PC market, but we are also committed to continue to support our PC business by expanding bill-of-material content, expanding market share, and acquiring new customers.

We plan to further expand the breadth of our product portfolio to increase our total bill-of-materials within an electronic system and to address the power requirements of additional electronic systems. Our product portfolio currently consists of approximately 1,900 products and we have introduced over 200 new products in this past fiscal year. We will continue to leverage our expertise to further increase our product lines, including higher performance power ICs, IGBTs and high, medium and low voltage MOSFETs, in order to broaden our addressable market and improve our margin profile. We are also in the process of developing a digital power controller product line based on the technology that we licensed from STMicro. We believe that our increased product offerings will allow us to penetrate new end-market applications and provide us with an important competitive advantage. OEMs and ODMs generally prefer to limit their supplier base to a smaller set of vendors capable of providing a comprehensive menu of products across multiple electronic platforms.

Leverage our power semiconductor expertise to drive new technology platforms

We believe that the ever-increasing demand for power efficiency in power semiconductors requires expertise in and a deep understanding of the interrelationship among device physics, process technologies, design and packaging. We also believe that engineers with experience and understanding of these multiple disciplines are in great demand but short supply. Within this context, we believe that we are well positioned to be a leader in providing total power management solutions due to our extensive pool of experienced scientists and engineers and our strong IP portfolio. Accordingly, we intend to leverage our expertise to increase the number of power discrete technology platforms and power IC designs, including future digital power controller products that are currently under development, to expand our product offerings and deliver complete power solutions for our targeted applications. In addition, our ability to develop new technology is enhanced by the operation of our own manufacturing facilities in Oregon and Chongqing, including the new 12-inch fab that is near completion.

Increase direct relationships and product penetration with OEM and ODM customers

We have developed direct relationships with key OEMs who are responsible for branding, designing and marketing a broad array of electronic products, as well as ODMs who have traditionally been responsible for manufacturing these products. While OEMs typically focus their design efforts on their flagship products, as the industry has evolved, ODMs are increasingly responsible for designing portions, or entire systems, of the products they manufacture for the OEMs. In addition, several ODMs are beginning to design, manufacture and brand their own proprietary products which they sell directly to consumers. We intend to strengthen our existing relationships and form new ones with both OEMs and ODMs by aligning our product development efforts with their product requirements, increasing the number of our products used within their systems, and leveraging our relationships to penetrate their other products. In addition, we are refocusing our research and development efforts to respond more directly to the market demand by designing and developing new products based on feedback from our customers, which also allows us to reduce time-to-market and sales cycles.

Leverage global business model for cost-effective growth

We intend to continue to leverage our global resources and regional strengths. We will continue to deploy marketing, sales and technical support teams in close proximity to our end customers. We plan to further expand and align our technical marketing and application support teams along with our sales team to better understand and address the needs of our end customers and their end-market applications, in particular for those with the new technology platforms developed in this past year and in the future. This will assist us in identifying and defining new technology trends and products and to help us gain additional design wins. In addition, we have established a joint venture with investment funds affiliated with the municipalities of Chongqing, China for the purpose of constructing a power semiconductor packaging, testing and wafer fabrication and we have made significant progress in the past fiscal year towards the completion of the joint venture facilities and commencement of production. We expect our collaboration with Chongqing will, in the long term, reduce the cost of manufacturing our products and accelerate the development of new products, while allowing us to gain valuable access to new customers in China.

Our products    

To serve the large and diverse analog market for power semiconductors, we have created a broad product portfolio consisting of two major categories: power discretes and power ICs.

Our power discretes products consist primarily of low, medium and high voltage power MOSFETs. Our low voltage MOSFET series is based on our proprietary silicon and package technologies, with deep application know how in various market segments. We have precisely defined technology platforms to address different requirements from various applications. Our medium voltage MOSFETs provide best optimized performance with high efficiency, high robustness and high reliability, and are widely used in applications such as TV backlighting, telecom power supplies, and industrial applications. We expanded our high voltage MOSFET portfolio by releasing our newest aMOS5 technology platform targeted to address robust consumer and industrial applications. Our high-voltage portfolio includes our proprietary insulated-gate bipolar transistor ("IGBT") technology, which we developed highly robust and easy-to-use solutions designed for industrial motor control and white goods applications.

Our power ICs deliver power as well as control and regulate the power management variables, such as the flow of current and level of voltage. We continued to expand our EZBuck power IC family with products that feature lower on-resistance, less power consumption, small footprint and thermally enhanced packages. While we derive the majority of our revenue from the sales of power discretes products, sales of power ICs continue to gain traction during the past years.

The following table lists our product families and the principal end uses of our products:

Power discrete products

Power discretes are used across a wide voltage and current spectrum, requiring them to operate efficiently and reliably under harsh conditions. Due to this wide applicability across diverse end-market applications, we market general purpose MOSFETs that are used in multiple applications as well as MOSFETs targeted for specific applications.

Our current power discrete product line includes industry standard trench MOSFETs, SRFETs, XSFET, electrostatic discharge, protected MOSFETs, high and mid-voltage MOSFETs and IGBTs.

Power IC products

In addition to the traditional monolithic or single chip design, we employ a multi-chip approach for the majority of our power ICs. This multi-chip technique leverages our proprietary MOSFET and advanced packaging technologies to offer integrated solutions to our customers. This allows us to update product portfolios by interchanging only the MOSFETs without changing the power management IC, thereby reducing the time required for new product introduction and providing optimal solutions to our customers. We believe that our power IC products improve our competitive position by enabling us to provide higher power density solutions to our end customers than our competitors.

The incorporation of both power delivery and power management functions tends to make power ICs more application specific because these two functions have to be properly matched to a particular end product. We have local technical marketing and applications engineers who closely collaborate with our end customers to help ensure that power IC specifications are properly defined at the beginning of the design stage.

New Product Introduction

We introduced several new products based on our proprietary technology platform and continue to expand our product family by introducing new solutions to computing, battery protection, and smart phone fast chargers. During the fourth quarter of fiscal year of 2018, we introduced new family of EZBuck™ regulators featuring I2C control. The new devices provide a compact, efficient power converter solution for next-generation chipsets and FPGAs used in high-end TVs, set-top boxes, data storage systems, servers and other embedded systems. We also introduced the AONX38168, which utilizes the latest 25V N-

Channel MOSFET technology platform, combining the low-side and high-side in a leadless surface mount package to offer high power density for server and telecommunication markets. During the third quarter of fiscal year of 2018, we introduced AONE36132, a 25V N-Channel MOSFET in a compact dual DFN 3.3x3.3 package, offering lower switch node ringing and lower parasitic inductance. Also we introduced a new Type-C Power Delivery compliant load switch with up to 28V over-voltage protection. This new device offers low RDS(ON) (40mohm) in a thermally enhanced 3x3mm DFN package, making it an ideal solution for the latest notebooks, ultrabooks, desktops, monitors, dockings/dongles, and Thunderbolt/USB Type-C PD applications. During the second quarter of fiscal year of 2018, we introduced AONR21357, which uses the improved P-Channel MOSFET process to achieve low power loss and reliable startup. This new P-Channel MOSFET is ideal for load switch applications in Notebook Adapter-In/ Battery In sockets. We also released AONS66916 production utilizing the latest Alpha Shield Gate Technology Generation 2 (AlphaSGT2), which enables higher efficiency and robustness to critical high density telecom and server applications. During the first quarter of fiscal year of 2018, we released AOTF190A60L, the first product in the new AMOS5TMHV MOSFET platform.  This device provides high-efficiency performance in an easy-to-use solution optimized for server power supplies, high-end computers, charging stations and other high-performance applications.  We also introduced AOZ5131QI, the latest generation of power modules. The new device enables high power-density voltage regulator solutions ideal for CPU and GPU power regulation in notebook PCs, servers, and graphic cards. In addition, we expanded our recently launched fast turn-off switched 650V H-series IGBT family with a 1200V rating. The new AOK40B120H1has been developed to address needs of industrial welding and high-frequency converters with 3-phase AC or high voltage DC input. The device offers excellent performance in high switching frequency applications, which can be a perfect fit for high voltage industrial welding machines.

Distributors and customers     

We have developed direct relationships with key OEMs, including Dell Inc., Hewlett-Packard Company, LG Electronics, Inc. and Samsung Group, most of which we serve through our distributors and ODMs. We sell to Samsung Group directly which accounted for 5.1%, 10.6% and 12.3% of our revenue for the fiscal years ended June 30, 2018 , 2017 and 2016 , respectively. In addition, based on our historical design win activities, our power semiconductors are also incorporated into products sold to certain OEMs.

Through our distributors, we provide products to ODMs who traditionally are contract manufacturers for OEMs. As the industry has evolved, ODMs are increasingly responsible for designing portions, or entire systems, of the products they manufacture for the OEMs. In addition, several ODMs are beginning to design, manufacture and brand their own proprietary products, which they sell directly to consumers. Our ODM customers include Compal Electronics, Inc., Foxconn, Quanta Computer Incorporated, Pegatron, Wistron Corporation and AOC International.

In order to take advantage of the expertise of end-customer fulfillment logistics and shorter payment cycles, we sell most of our products to distributors. In general, under the agreements with our distributors, they have limited rights to return unsold merchandise, subject to time and volume limitations. As of June 30, 2018 , 2017 and 2016 , our two largest distributors were WPG Holdings Limited, or WPG, and Promate Electronic Co. Ltd., or Promate. Sales to WPG and Promate accounted for 35.2% and 28.3% of our revenue, respectively, for the fiscal year ended June 30, 2018 , 35.8% and 26.9% of our revenue, respectively, for the fiscal year ended June 30, 2017 , and 37.2% and 23.8% of our revenue, respectively, for fiscal year ended June 30, 2016 , respectively.

Sales and marketing    

Our marketing division is responsible for identifying high growth markets and applications where we believe our technology can be effectively deployed. We believe that the technical background of our marketing team, including application engineers, helps us better define new products and identify potential end customers and geographic and product market opportunities. For example, as part of our market diversification strategy, we have deployed and plan to recruit more for our new market segments, field application engineers, or FAEs, who provide real-time and on-the-ground responses to our end customer needs. FAEs work with our end customers to understand their requirements, resolve technical problems, strive to anticipate future customer needs and facilitate the design-in of our products into the end products of our customers. We believe this strategy increases our share of revenue opportunities within the applications we currently serve, as well as in new end-market applications.

Our sales team consists of sales persons, field application engineers, customer service representatives and customer quality engineers who are responsible for key accounts. We strategically position our team near our end customers through our offices in Taipei, Hong Kong, Shenzhen, Shanghai, Tokyo, Seoul, Heilbronn, Germany, and Sunnyvale, California, complemented by our applications centers in Sunnyvale and Shanghai. In addition, our distributors and sales representatives assist us in our sales and marketing efforts by identifying potential customers, sourcing additional demand and promoting our products, in which case we may pay a sales commission to these distributors.

Our sales cycle varies depending on the types of products and can range from six to eighteen months.  In general, our traditional power discrete products in the PC and TV applications are moving more rapidly through the design and marketing processes, therefore they generally have shorter sales cycle.  In contrast, our newer Power IC and IGBT products, mostly in the power supply, home appliance and industrial applications, require a more extended design and marketing timeline and thus have longer sales cycle.  Typically, our sales cycle for all products comprises of the following steps:

Competition

The power semiconductor industry is characterized by fragmentation with many competitors. We compete with different power semiconductor suppliers, depending on the type of product lines and geographical area. Our key competitors in power discretes and power ICs are primarily headquartered in the United States, Japan, Europe and Taiwan. Our major competitors in power discretes include Infineon Technologies AG, MagnaChip Semiconductor Corporation, ON Semiconductor Corp., STMicroelectronics N.V., Toshiba Corporation, Diodes Incorporated and Vishay Intertechnology, Inc. Our major competitors for our power ICs include Global Mixed-mode Technology Inc., Monolithic Power Systems, Inc., Richtek Technology Corp., Semtech Corporation and Texas Instruments Inc..

Our ability to compete depends on a number of factors, including:

Some of our competitors have longer operating histories, more brand recognition, and significantly greater financial, technical, research and development, sales and marketing, manufacturing and other resources. However, we believe that we can compete effectively through our integrated and innovative technology platform and design capabilities, including our multi-chip approach to power IC products, strategic global business model, expanding portfolio of products, diversified and broad customer base, and excellent on-the-ground support and quick time to market for our products.

Seasonality    

As we provide power semiconductors used in consumer electronic products, our business is subject to seasonality. Our sales seasonality is affected by a number of factors, including global and regional economic conditions as well as the PC market conditions, revenue generated from new products, changes in distributor ordering patterns in response to channel inventory adjustments and end customer demand for our products and fluctuations in consumer purchase patterns prior to major holiday seasons.

Backlog        

Our sales are made primarily pursuant to standard purchase orders from distributors and direct customers. The amount of backlog to be shipped during any period depends on various factors, and all orders are subject to cancellation or modification, usually with no penalty to customers. The quantities actually purchased by customers, as well as shipment schedules, are frequently revised to reflect changes in both the customers' requirements and in manufacturing availability. Therefore, our backlog at any point in time is not a reliable indicator of our future revenue.

Research and development    

Because we view technology as a competitive advantage, we invest significant time and capital into research and development to address the technology intensive needs of our end customers. Our research and development expenditures for the fiscal years of 2018 , 2017 and 2016 were $37.3 million , $29.8 million and $26.0 million , respectively. Our research and development expenditures primarily consist of personnel compensation, prototypes, engineering materials, simulation and design tools and test and analyzer equipment. Our new product development efforts continue to focus on developing products with higher speed, higher efficiency and reliability, higher power density, greater performance and lower costs. We have research and development teams in Silicon Valley (Sunnyvale, California), Oregon, Taipei, Taiwan, and Shanghai, China. We believe that these diverse research and development teams enable us to develop leading edge technology platforms and new products. Our areas of research and development focus include:

Packaging technologies : Consumer demand for smaller and more compact electronic devices with higher power density is driving the need for advanced packaging technology. Our group of dedicated packaging engineers focuses on smaller form factor, higher power output with efficient heat dissipation and cost-effectiveness. We have invested resources to develop and enhance our proprietary packaging technologies, including the establishment of our in-house packaging and testing facilities. We believe that our efforts to develop innovative packaging technologies will continue to provide new and cost-effective solutions with higher power density to our customers. During the fiscal year ended June 30, 2018 , we continued our diversification strategies by developing new silicon and packaging platforms to expand our SAM and offer higher performance products.

Process technology and device physics: We focus on specialized process technology in the manufacturing of our products, including vertical DMOS, Shielded Gate Trench, Trench field stop IGBTs, charge-balance high voltage MOSFETs, Schottky Diode and BCDMOS processes. Our process engineers work closely with our design team to deploy and implement our proprietary manufacturing processes at our Oregon fab, and more recently, at the Chongqing manufacturing facility under the JV, as well as the third-party foundries that fabricate our wafers. We also expect our Chongqing manufacturing facility under the JV, including the 12-inch fab, will provide us with enhanced ability to develop and accelerate new process technology for advanced products. To improve our process technology, we continue to develop and enhance our expertise in device physics in order to better understand the physical characteristics of materials and the interactions among these materials during the manufacturing process.

New products and new technology platforms: We also invest significantly in the development of new technology platforms and introduction of new products. Because power management affects all electronic systems, we believe that developing a wide portfolio of products enables us to target new applications in addition to expanding our share of power management needs served within existing applications.

As a technology company, we will continue our significant investment in research and development in our low voltage and high voltage power discretes and power ICs by developing new technology platforms and new products that allow for better product performance, more efficient packages and higher levels of integration.

Operations    

The manufacture of our products is divided into two major steps: wafer fabrication and packaging and testing.

Wafer fabrication

Our Oregon fab allows us to accelerate the development of our technology and products, as well as to provide better services to our customers. We allocate our wafer production between our in-house facility and third-party foundries, although in the past three years, we have gradually reduced our reliance on third-party foundries and increased allocation of capacity to our Oregon fab. Currently our main third-party foundry is Shanghai Hua Hong Grace Electronic Company Limited, ("HHGrace"), or formerly HHNEC, located in Shanghai. HHGrace has been manufacturing wafers for us since 2002. HHGrace manufactured 15.4% , 18.6% and 25.0% of the wafers used in our products for the fiscal years ended June 30, 2018 , 2017 and 2016 , respectively.

On March 29, 2016, we entered into the JV agreement with two investment funds affiliated with the municipalities of Chongqing for the purpose of constructing a power semiconductor packaging, testing and 12-inch wafer fabrication facility in the Liangjiang New Area of Chongqing. We substantially completed our assembly and testing and 12-inch wafer fab facilities during the quarter ended June 30, 2018. We expect to commence limited mass production for assembly and testing in the second half of calendar year 2018, and the trial production of the 12-inch wafer fabrication facility toward the end of calendar year 2018. We believe the joint venture will increase and diversify our customer base, particularly in China, and accelerate the development of proprietary process technology.

Packaging and testing

Completed wafers from the foundries are sent to our in-house packaging and testing facilities or to our subcontractors, where the wafers are cut into individual die, soldered to lead frames, wired to terminals and then encapsulated in protective packaging. After packaging, all devices are tested in accordance with our specifications and substandard or defective devices are rejected. We have established quality assurance procedures that are intended to control quality throughout the manufacturing process, including qualifying new parts for production at each packaging facility, conducting root cause analysis, testing for lots with process defects and implementing containment and preventive actions. The final tested products are then shipped to our distributors or customers.

Our in-house and wholly-owned packaging and testing facilities are located in Shanghai, China which handle most of our packaging and testing requirements for our products. During the quarter ended September 30, 2016, we fulfilled our obligations to contribute certain packaging equipment as required by the JV agreement by transferring the legal titles of such equipment to the JV Company and we expect the JV Company to handle a portion of our packaging and testing requirement following the commencement of production. We continuously increase the outsourcing portion of our packaging and testing requirements to other contract manufacturers to minimize the effect of market fluctuation. Our facilities have the combined capacity to package and test over 600 million parts per month and have available floor space for new package introductions. We believe our ability to package and test our products internally represents a strategic advantage as it protects our proprietary packaging technology, increases the rate of new package introductions, reduces operating expenses and ultimately improves our profit margins.

Quality assurance    

Our quality assurance practices aim to consistently provide our end customers with products that are reliable, durable and free of defects. We strive to do so through design for manufacturing, and continuous improvement in our product design and manufacturing and close collaboration with our manufacturing partners. Our manufacturing operations in China and our manufacturing facility in Oregon are certified to the ISO9001 and IATF16949:2016. These Quality Management System certifications are in recognition of our quality assurance standards. Both ISO9001 and IATF16949:2016 are sets of criteria and procedures established by International Organization of Standardization for developing a fundamental quality management system and focusing on continuous improvement, defect prevention and the reduction of variation and waste. Our products are also in compliance with Restrictions on the use of Hazardous Substances, or RoHS 2.0.

We maintain a supplier management and process engineering team in Shanghai that works with our third-party foundries and packaging and testing subcontractors to monitor the quality of our products, which is designed to ensure that manufacturing of our products, is in strict compliance with our process controls, monitoring procedures and product requirements. We also conduct periodic reviews and annual audits to ensure supplier performance. For example, we examine the results of statistical process control systems, implement preventive maintenance, verify the status of quality improvement projects and review delivery time metrics. In addition, we rate and rank each of our suppliers every quarter based on factors such as their quality and performance. Our facility in Oregon integrates manufacturing process controls through our manufacturing execution system coupled with wafer process controls that include monitoring procedures, preventative maintenance, statistical process control, and testing to ensure that finished wafers delivered will meet and exceed quality and reliability requirements. All materials used to manufacture wafers are controlled through a strict qualification process.

Our manufacturing processes use many raw materials, including silicon wafers, gold, copper, molding compound, petroleum and plastic materials and various chemicals and gases. We obtain our raw materials and supplies from a large number of sources. Although supplies for the raw materials used by us are currently adequate, shortages could occur in various essential materials due to interruption of supply or increased demand in the industry.

Intellectual property rights     

Intellectual property is a critical component of our business strategy, and we intend to continue to invest in the growth, maintenance and protection of our intellectual property portfolio. We own significant intellectual property in many aspects of

power semiconductor technology, including device physics and structure, wafer processes, circuit designs, packaging, modules and subassemblies. We have also entered into intellectual property licensing agreements with other companies, including On Semiconductor Corp. and Giant Semiconductor Corporation, to use selected third-party technology for the development of our products, although we do not believe our business is dependent to any significant degree on any individual third-party license agreement. On September 5, 2017, we entered into a license agreement with STMicroelectronics International N.V. ("STMicro"), pursuant to which STMicro granted us a world-wide, royalty-free and fully-paid license to use its technologies to develop, market and distribute certain digital multi-phase controller products, which have been offered previously by STMicro. This license agreement allows us to develop a new digital power business that will design and offer a full suite of advance digital power controller products. 

While we focus our patent efforts in the United States, we file corresponding foreign patent applications in other jurisdictions, such as China and Taiwan, when filing is justified by cost and strategic importance. The patents are increasingly important to remain competitive in our industry, and a strong patent portfolio will facilitate the entry of our products into new markets. As of June 30, 2018 , we had 722 patents issued in the United States, of which 9 were acquired, 2 were licensed and 711 were based on our research and development efforts, and these patents are set to expire between 2018 and 2037 . Within these patents, 4 patents will expire in 2018 . We do not expect that the expiration of these 4 patents will have a material adverse impact on our patent position. We also had a total of 667 foreign patents, including 259 Chinese patents, 383 Taiwanese patents, 17 Korean patents, 4 Hong Kong patents and 4 Japanese patents as of June 30, 2018 . Substantially all of our foreign patents were based on our research and development efforts. These foreign patents will expire in the years between 2018 and 2037 . In addition, as of June 30, 2018 , we had a total of 278 patent applications, of which 108 patents were pending in the United States, 93 patents were pending in China, 45 patents were pending in Taiwan and 32 patents were pending in other countries.

As our technologies are deployed in new applications and as we diversify our product portfolio based on new technology platforms, we may be subject to new potential infringement claims. Patent litigation, if and when instituted against us, could result in substantial costs and a diversion of our management's attention and resources. However, we are committed to vigorously defending and protecting our investment in our intellectual property. Therefore, the strength of our intellectual property program, including the breadth and depth of our portfolio, will be critical to our success in the new markets we intend to pursue.

In addition to patent protection, we also rely on a combination of trademark, copyright (including mask work protection), trade secret laws, contractual provisions and similar laws in other jurisdictions. We also enter into confidentiality and invention assignment agreements with our employees, consultants, suppliers, distributors and customers and seek to control access to, and distribution of, our proprietary information.

Environmental matters    

The semiconductor production process, including the semiconductor wafer manufacturing and packaging process, generates air emissions, liquid wastes, waste water and other industrial wastes. We have installed various types of pollution control equipment for the treatment of air emissions and liquid waste and equipment for recycling and treatment of water in our packaging and testing facilities in China and wafer manufacturing facility in Oregon, USA. Waste generated at our manufacturing facilities, including but not limited to acid waste, alkaline waste, flammable waste, toxic waste, oxide waste and self-igniting waste, is collected and sorted for proper disposal. Our operations in China are subject to regulation and periodic monitoring by China's State Environmental Protection Bureau, as well as local environmental protection authorities, including those under the Shanghai Municipal Government, which may in some cases establish stricter standards than those imposed by the State Environmental Protection Bureau. Our operation in Oregon is subject to Oregon Department of Environmental Regulations, Federal Environmental Protection Agency laws and regulations, and local jurisdictional regulations. We believe that we have been in material compliance with applicable environmental regulations and standards and have not had a material or adverse effect on our results of operations from complying with these regulations.

We have implemented an ISO 14001 environmental management system in our manufacturing facilities in China and Oregon. We also require our subcontractors, including foundries and assembly houses, to meet ISO14001 standards. We believe that we have adopted pollution control measures for the effective maintenance of environmental protection standards consistent with the requirements applicable to the semiconductor industry in China and the U.S.

Our products sold in worldwide are subject to RoHS in Electrical and Electronic Equipment, which requires that the products do not contain more than agreed levels of lead, cadmium, mercury, hexavalent chromium, polybrominated biphenyl and polybrominated diphenyl ether flame retardants. Our manufacturing facilities in China also obtained QC080000 certification, which is an IECQ Certificate of Conformity Hazardous Substance Process Management for European Directive

2002/95/EC requirements and a Certificate of Green Partner for Sony Green Partner Program. We avoid using these restricted materials to the extent possible when we design our products.

We are also subject to SEC rules that require diligence, disclosure and reporting on whether certain minerals and metals, known as conflict minerals, used in our products originate from the Democratic Republic of Congo and adjoining countries. As of June 30, 2018 , 2017 and 2016 , we were in compliance with the related conflict minerals rule.

Employees    

As of June 30, 2018 , we had approximately 3,340 employees, of which approximately 590 were located in the United States, 2,630 were located in China, and 120 were located in other parts of Asia. None of our employees is represented by a collective bargaining agreement. We consider our relationships with our employees to be good.

Executive Officers     

The following table lists the names, ages and positions of our executive officers as of July 31, 2018 . There are no family relationships between any executive officer.

Mike F. Chang, Ph.D ., is the founder of our company and has served as our Chairman of the Board and Chief Executive Officer since the incorporation of our company. Dr. Chang has extensive experience in both technology development and business operations in the power semiconductor industry. Prior to establishing our company, Dr. Chang served as the Executive Vice President at Siliconix Incorporated, a subsidiary of Vishay Intertechnology Inc., a global manufacturer and supplier of discrete and other power semiconductors, or Siliconix, from 1998 to 2000. Dr. Chang also held various management positions at Siliconix from 1987 to 1998. Earlier in his career, Dr. Chang focused on product research and development in various management positions at General Electric Company from 1974 to 1987. Dr. Chang received his B.S. in electrical engineering from National Cheng Kung University, Taiwan, and M.S. and Ph.D. in electrical engineering from the University of Missouri.

Yueh-Se Ho, Ph.D ., is a co-founder of our company and has served as our Chief Operating Officer since January 2006 and our director since March 2006. Dr. Ho has held various operational management positions in our company since our inception, including the Vice President of Worldwide Operations from 2003 to 2006 and the Vice President of Back End Operations from 2000 to 2003. Prior to co-founding our company, Dr. Ho served as the Director of Packaging Development and Foundry Transfer at Siliconix from 1998 to 2000. Dr. Ho received his B.S. in chemistry from Tamkang University, Taiwan, and Ph.D. in chemistry from the University of Pittsburgh.

Yifan Liang has been serving as our Chief Financial Officer since August 2014 and Corporate Secretary since November 2013. Mr. Liang served as our Interim Chief Financial Officer from November 2013 to August 2014, our Chief Accounting Officer since October 2006, and our Assistant Corporate Secretary from November 2009 to November 2013. Mr. Liang joined our company in August 2004 as our Corporate Controller. Prior to joining us, Mr. Liang held various positions at PricewaterhouseCoopers LLP, or PwC, from 1995 to 2004, including Audit Manager in PwC's San Jose office. Mr. Liang received his B.S. in management information system from the People's University of China and M.A. in finance and accounting from the University of Alabama.

Available Information

Our filing documents and information with the Securities and Exchange Commission (the "SEC") are available free of charge electronically through our Internet website, www.aosmd.com. as soon as reasonably practicable after we electronically file such material with, or furnish it to, the SEC. Additionally, these filings may be obtained by visiting the Public Reference Room of the SEC at 100 F Street, NE, Washington, DC 20549 or by calling the SEC at 1-800-SEC-0330, by sending an electronic message to the SEC at [email protected]. In addition, the SEC maintains a website (www.sec.gov) that contains reports, proxy statements, and other information that we file electronically.

Risks Related to Our Business

Our joint venture with the Chongqing government may not succeed as expected.

In March 2016, we entered into a joint venture contract (the "JV Agreement") with two investment funds owned by the municipalities of Chongqing, China (the "Chongqing Funds"), pursuant to which we and the Chongqing Funds formed a joint venture (the "JV Company") for the purpose of constructing a power semiconductor packaging/testing and wafer fabrication facility. The JV Company is expected to commence assembly and testing mass production in the second half of calendar year 2018, and trial production of the 12-inch wafer fabrication facilities toward the end of calendar year 2018. The initial ramp up of the JV Company's operations is costly and for the short term will negatively impact our results of operations. While we believe the JV Transaction will enhance our ability to accelerate growth and improve our profitability, there is no guarantee that it will succeed as we initially expected. We may encounter unanticipated difficulties and obstacles that may delay or prevent the commencement of the JV Company's operation, some of which are outside of our control. These difficulties may include unexpected costs and delays in transferring our assembly and testing operations to the new facility; inability to coordinate and integrate the labor forces; failure of the Chongqing Funds to meet their obligations under the JV Agreement, such as delays in capitalizing the JV Company based on our original timeline; and inability to provide customers with required services.

Even after the JV Company commences operation, we may not fully realize the anticipated benefits of the project, such as cost savings, improvement in working capital, increased gross margin, revenue and profitability, enhanced market share for our products; and increased diversification of our products and customers.  The establishment and operation of a new manufacturing facility involve significant risks and challenges, including, but are not limited to, the following:

In addition, we may be subject to the risk of under-utilization of the facilities at the JV Company. The operation of the JV Company's facilities, including the assembly and testing facilities and the fab, requires significant fixed cost. In order to manage the capacity of the wafer fabrication facility efficiently, we must perform a forecast of long-term market demand and general economic conditions for our products. Because market conditions may vary significantly and unexpectedly, our forecast may change significantly at any time, and we may not be able to make timely adjustments to our fabrication capacity in response to these changes. If our forecast is incorrect or if we are not able to fully utilize the capacities of the facilities at the JV Company, we may not be able to absorb the cost of operation, which will adversely affect our results of operations.

Any of the foregoing risks could materially reduce the expected return of our investment in the JV Transaction and adversely affects our business operations, financial performance and the trading price of our shares.

Possible new tariffs on imported goods from China could adversely affect our business operations.

The President of the United States has recently ordered U.S. government agencies to consider a proposed 25% tariff on a wide range of goods and materials imported from China, in addition to the U.S. tariffs already imposed.  These goods may include products and applications, including consumer electronics, that incorporate our power discrete and power IC products. In response, China announced a plan to impose tariffs on certain American products if these additional U.S. tariffs are imposed.  The resulting trade war could have a significant adverse effect on world trade and the world economy. While it is too early to predict if the additional potential U.S. tariffs will be imposed, or how the recently enacted tariffs will impact our business, we believe that the imposition of the potential additional tariffs by the U.S. government on products incorporating our power semiconductors could deter our U.S. customers from purchasing our products originating from China. If so, this could reduce demand for our power semiconductor products or result in pricing adjustments that would lower our gross margin, which could have a material adverse effect on our business and results of operations.

We may not be able to successfully develop our digital power business.

In September 2017, we entered into a license agreement with STMicro, which allows us to develop and market certain digital power multi-phase controller products and enter into a new market, primarily in the computer server segment. We are in the process of developing this new digital power business and expect to incur significant startup costs, including costs relating to the hiring and compensation of qualified engineers and technical staff; development of marketing and sales infrastructure, particularly in the computer server market; and other research and development and management activities. We do not expect this new business to generate sufficient revenue to offset our costs in the short term, and there is no guarantee that our attempt to develop a profitable digital business will ultimately succeed. The success of our new digital power business depends on a number of factors, including the following:

Any one of these factors may negatively impact our ability to create a successful digital power business, which would adversely affect our financial condition and results of operations.

The decline of personal computing ("PC") markets may have a material adverse effect on our results of operations.

A significant amount of our revenue is derived from sales of products in the PC markets such as notebooks, motherboards and notebook battery packs.  Our revenue from the PC markets accounted for approximately 41.6% , 39.1% and 38.5% of our total revenue for the years ended 2018 , 2017 and 2016 , respectively. The increasing popularity of smaller, mobile computing devices such as tablets and smart phones with touch interfaces is rapidly changing the PC markets both in the United States and abroad.  In the past, we experienced a significant reduction in the demand for our products due to the declining PC markets, which had negatively impacted our revenue, profitability and gross margin. The decline of the PC markets also adversely affected our ability to adjust inventory levels in response to the lower shipments, which had negatively impacted our gross margins.

Our diversification into different market segments may not succeed according to our expectations and may expose us to new risks and place significant strains on our management, operational, financial and other resources.

As part of the growth strategy to diversify our product portfolio and in response to the rapid decline of the PC markets, we have been developing new technologies and products designed to penetrate into other markets and applications, including merchant power supplies, flat panel TVs, smart phones, tablets, gaming consoles, lighting, datacom, telecommunications, home appliances and industrial motor controls. However, there is no guarantee that these diversification efforts will be successful. As a new entrant to some of these markets, we may face intense competition from existing and more established providers and encounter other unexpected difficulties, any of which may hinder or delay our efforts to achieve success. In addition, our new products may have long design and sales cycles, therefore if our diversification efforts fail to keep pace with the declining PC markets, we may not be able to alleviate its negative impact on our results of operations.

Our diversification into different market segments may place a significant strain on our management, operational, financial and other resources. To manage this diversification effectively, we will need to take various actions, including:

Our failure to execute any of the above actions successfully or timely may have an adverse effect on our business and financial results.

Our operating results may fluctuate from period to period due to many factors, which may make it difficult to predict our future performance.

Our periodic operating results may fluctuate as a result of a number of factors, many of which are beyond our control. These factors include, among others:

Any one or a combination of the above factors and other risk factors described in this section may cause our operating results to fluctuate from period to period, making it difficult to predict our future performance. Therefore, comparing our

operating results on a period-to-period basis may not be meaningful, and you should not rely on our past results as an indication of our future performance.

Our revenue may fluctuate significantly from period to period due to ordering patterns from our distributors and seasonality.

Demand for our products from our end customers fluctuates depending on their sales outlooks and market and economic conditions. Accordingly, our distributors place purchase orders with us based on their forecasts of end customer demand. Because these forecasts may not be accurate, channel inventory held at our distributors may fluctuate significantly due to the difference between the forecasts and actual demand. As a result, distributors adjust their purchase orders placed with us in response to changing channel inventory levels, as well as their assessment of the latest market demand trends. A significant decrease in our distributors' channel inventory in one period may lead to a significant rebuilding of channel inventory in subsequent periods, or vice versa, which may cause our quarterly revenue and operating results to fluctuate significantly.

In addition, because our power semiconductors are used in consumer electronics products, our revenue is subject to seasonality. Our sales seasonality is affected by a number of factors, including global and regional economic conditions as well as the PC market conditions, revenue generated from new products, changes in distributor ordering patterns in response to channel inventory adjustments and end customer demand for our products and fluctuations in consumer purchase patterns prior to major holiday seasons. In recent year, broad fluctuations in the semiconductor markets and the global economic conditions, in particular the decline of the PC market conditions, have had a more significant impact on our results of operations, than seasonality, and have made it difficult to assess the impact of seasonal factors on our business.

If we are unable to introduce or develop new and enhanced products that meet or are compatible with our customer's product requirements in a timely manner, it may harm our business, financial position and operating results.

Our success depends upon our ability to develop and introduce new and enhanced products that meet or are compatible with our customer's specifications, performance standards and other product requirements in a timely manner. The development of new and enhanced products involves highly complex processes, and at times we have experienced delays in the introduction of new products. Successful product development and introduction of new products depends on a number of factors, including the accurate product specification; timely completion of design; achievement of manufacturing yields; timely response to changes in customers' product requirements; quality and cost-effective production; and effective marketing. Since many of our products are designed for specific applications, we must frequently develop new and enhanced products jointly with our customers. In the past, we have encountered product compatibility issues with a major OEM that has negatively impacted our financial results, and although we have resolved fully such issues with the OEM, there is no guarantee that the same compatibility issues will not occur in the future with other OEMS. If we are unable to develop or acquire new products that meet or are compatible with our customer's specification and other product requirements in a timely manner, we may lose revenue or market shares with our customers, which could have a material adverse effect on our business, financial position and operating results.

We may not win sufficient designs, or our design wins may not generate sufficient revenue for us to maintain or expand our business.

We invest significant resources to compete with other power semiconductor companies to obtain winning competitive bids for our products in selection processes, known as "design wins." Our effort to obtain design wins may detract us from or delay the completion of other important development projects, impair our relationships with existing end customers and negatively impact sales of products under development. In addition, we cannot be assured that these efforts would result in a design win, that our product would be incorporated into an end customer's initial product design, or that any such design win would lead to production orders and generate sufficient revenue. Furthermore, even after we have qualified our products with a customer and made sales, subsequent changes to our products, manufacturing processes or suppliers may require a new qualification process, which may result in delay and excess inventory. If we cannot achieve sufficient design wins in the future, or if we fail to generate production orders following design wins, our ability to grow our business and improve our financial results will be harmed.

Our success depends upon the ability of our OEM end customers to successfully sell products incorporating our products.

The consumer end markets, in particular the PC market, in which our products are used are highly competitive. Our OEM end customers may not successfully sell their products for a variety of reasons, including:

Our success depends on the ability of our OEM end customers to sell their products incorporating our products. In addition, we have expanded our business model to include more OEMs in our direct customer base. The failure of our OEM end customers to achieve or maintain commercial success for any reason could harm our business, results of operations, and financial condition and prospects.

The operation of our Oregon fab subjects us to additional risks and the need for additional capital expenditures which may negatively impact our results of operations.

The operation of the Oregon fab requires significant fixed manufacturing cost. In order to manage the capacity of the wafer fabrication facility efficiently, we must perform a forecast of long-term market demand and general economic conditions for our products. Because market conditions may vary significantly and unexpectedly, our forecast may change significantly at any time, and we may not be able to make timely adjustments to our fabrication capacity in response to these changes. During periods of continued decline in market demand, in particular the decline of the PC market, we may not be able to absorb the excess inventory and additional costs associated with operating the facility at higher capacity, which may adversely affect our operating results. Similarly, during periods of unexpected increase in customer demand, we may not be able to ramp up production quickly to meet these demands, which may lead to the loss of significant revenue opportunities. The manufacturing processes of a fabrication facility are complex and subject to interruptions. We may experience production difficulties, including lower manufacturing yields or products that do not meet our or our customers' specifications, and problems in ramping production and installing new equipment. These difficulties could result in delivery delays, quality problems and lost revenue opportunities. Any significant quality problems could also damage our reputation with our customers and distract us from the development of new and enhanced product which may have a significant negative impact on our financial results.

In addition, semiconductor manufacturing has historically required an upgrading of process technology from time to time to remain competitive, as new and enhanced semiconductor processes are developed which permit smaller, more efficient and more powerful semiconductor devices. Accordingly, we may have to incur substantial capital expenditures and install significant production capacity at our in-house fabrication facility to support new technologies and increased production volume, which may cause delay in our ability to deliver new products or negatively impact our results of operations.

Defects and poor performance in our products could result in loss of customers, decreased revenue, unexpected expenses and loss of market share, and we may face warranty and product liability claims arising from defective products.

Our products are complex and must meet stringent quality requirements. Products as complex as ours may contain undetected errors or defects, especially when first introduced or when new versions are released. Errors, defects or poor performance can arise due to design flaws, defects in raw materials or components or manufacturing anomalies, which can affect both the quality and the yield of the product. It can also be potentially dangerous as defective power components, or improper use of our products by customers, may lead to power overloads, which could result in explosion or fire. As our products become more complex, we face higher risk of undetected defects, because our testing protocols may not be able to fully test the products under all possible operating conditions. In the past, we have experienced defects in our products and these products were returned to us and subsequently scrapped or sold at a discount. Any actual or perceived errors, defects or poor performance in our products could result in the replacement or recall of our products, shipment delays, rejection of our products, damage to our reputation, lost revenue, diversion of our engineering personnel from our product development efforts in order to address or remedy any defects and increases in customer service and support costs, all of which could have a material adverse effect on our business and operations.

Furthermore, as our products are typically sold at prices much lower than the cost of the equipment or other devices incorporating our products, any defective, inefficient or poorly performing products, or improper use by customers of power components, may give rise to warranty and product liability claims against us that exceed any revenue or profit we receive from the affected products. Historically, we have received claims from our customers for charges such as their labor and other costs replacing defective parts, their lost profit, and/or penalty. We could incur significant costs and liabilities if we are sued

and if damages are awarded against us. There is no guarantee that our insurance policies will be available or adequate to protect against such claims. Costs or payments we may make in connection with warranty and product liability claims or product recalls may adversely affect our financial condition and results of operations.

If we do not forecast demand for our products accurately, we may experience product shortages, delays in product shipment, excess product inventory, or difficulties in planning expenses, which will adversely affect our business and financial condition.

We manufacture our products according to our estimates of customer demand. This process requires us to make numerous forecasts and assumptions relating to the demand of our end customers, channel inventory, and general market conditions. Because we sell most of our products to distributors, who in turn sell to our end customers, we have limited visibility as to end customer demand. Furthermore, we do not have long-term purchase commitments from our distributors or end customers, and our sales are generally made by purchase orders that may be cancelled, changed or deferred without notice to us or penalty. As a result, it is difficult to forecast future customer demand to plan our operations.

The utilization of our manufacturing facilities and the provisions for inventory write-downs are important factors in our profitability. If we overestimate demand for our products, or if purchase orders are canceled or shipments delayed, we may have excess inventory, which may result in adjustments to our production plans. These adjustments to our productions may affect the utilization of our own wafer fabrication and packaging facilities. If we cannot sell certain portion of the excess inventory, it will affect our provisions for inventory write-downs. Our inventory write-down provisions are subject to adjustment based on events that may not be known at the time the provisions are made, and such adjustments could be material and impact our financial results negatively.

If we underestimate demand, we may not have sufficient inventory to meet end-customer demand, and we may lose market share and damage relationships with our distributors and end customers and we may have to forego potential revenue opportunities. Obtaining additional supply in the face of product shortages may be costly or impossible, particularly in the short term, which could prevent us from fulfilling orders in a timely manner or at all.

In addition, we plan our operating expenses, including research and development expenses, hiring needs and inventory investments, base in part on our estimates of customer demand and future revenue. If customer demand or revenue for a particular period is lower than we expect, we may not be able to proportionately reduce our fixed operating expenses for that period, which would harm our operating results.

We face intense competition and may not be able to compete effectively which could reduce our revenue and market share.

The power semiconductor industry is highly competitive and fragmented. If we do not compete successfully against current or potential competitors, our market share and revenue may decline. Our main competitors are primarily headquartered in the United States, Japan, Taiwan and Europe. Our major competitors for our power discretes include Infineon Technologies AG, MagnaChip Semiconductor Corporation, ON Semiconductor Corp., STMicroelectronics N.V., Toshiba Corporation, Diodes Incorporated and Vishay Intertechnology, Inc. Our major competitors for our power ICs include Global Mixed-mode Technology Inc., Monolithic Power Systems, Inc., Richtek Technology Corp., Semtech Corporation and Texas Instruments Inc.

We expect to face competition in the future from our competitors, other manufacturers, designers of semiconductors and start-up semiconductor design companies. Many of our competitors have competitive advantages over us, including:

In addition, the semiconductor industry has experienced increased consolidation over the past several years that may adversely affect our competitive position. For example, On Semiconductor Corporation acquired Fairchild Semiconductor International Inc. in September 2016; Avago Technologies Limited (now Broadcom Limited ("Broadcom")) acquired Broadcom Corporation in February 2016 and LSI Corporation in May 2014; Intel acquired Altera Corporation in December 2015; and NXP Semiconductors acquired Freescale Semiconductor, Ltd. in December 2015. Consolidation among our competitors could lead to a less favorable competitive landscape, capabilities and market share, which could harm our business and results of operations.

If we are unable to compete effectively for any of the foregoing or other reasons, our business, results of operations, and financial condition and prospects will be harmed.

We depend partly on third-party semiconductor foundries to manufacture our products and implement our fabrication processes, and any failure to maintain sufficient foundry capacity and control the cost of production could significantly delay our ability to ship our products, damage our relationships with customers, reduce our sales and increase expenses.

The allocation of our wafer production between in-house facility and third-party foundries may fluctuate from time to time. We expect to continue to rely in part on third party foundries to meet our wafer requirements. Although we use several independent foundries, our primary third-party foundry is HHGrace, which manufactured 15.4% , 18.6% and 25.0% of the wafers used in our products for the fiscal years ended June 30, 2018 , 2017 and 2016 , respectively.

We place our purchase orders with foundries based on sales forecasts for our products. If any third-party foundry does not provide competitive pricing or is not able to meet our required capacity for any reason, we may not be able to obtain the required capacity to manufacture our products timely or efficiently. From time to time, third party suppliers may extend lead-times, limit supplies or increase prices due to capacity constraints or other factors, and we may experience a shortage of capacity on an industry-wide basis that may last for an extended period of time. There is no assurances of that we will be able to maintain sufficient capacity to meet the full demand from our customers, and failure to do so will adversely affect our results of operations. If we cannot maintain sufficient capacity or control pricing with our existing third-party foundries, we may need to increase our own manufacturing capacity, and there is no assurance that we can ramp up the production of the Oregon fab timely to meet the increased demand. If not, we may need to seek alternative foundries, which may not be available on commercially reasonable terms, or at all. In addition, the process for qualifying a new foundry is time consuming, difficult and may not be successful, particularly if we cannot integrate our proprietary process technology with the process used by the new foundry. Using a foundry with which we have no established relationship could expose us to potentially unfavorable pricing, unsatisfactory quality or insufficient capacity allocation.

In addition, even though we have been transferring more new product developments to our Oregon fab, we still rely on third-party foundries significantly to effectively implement certain of our proprietary technology and processes and also require their cooperation in developing new fabrication processes. Any failure to do so may impair our ability to introduce new products and on time delivery of wafers for our existing products. In order to maintain our profit margins and to meet our customer demand, we need to achieve acceptable production yields and timely delivery of silicon wafers. As is common in the semiconductor industry, we have experienced, and may experience from time to time, difficulties in achieving acceptable production yields and timely delivery from third-party foundry vendors. Minute impurities in a silicon wafer can cause a substantial number of wafers to be rejected or cause numerous die on a wafer to be defective. Low yields often occur during the production of new products, the migration of processes to smaller geometries or the installation and start up of new process technologies.

We face a number of other significant risks associated with outsourcing fabrication, including:

Any of the foregoing risks could delay shipment of our products, result in higher expenses and reduced revenue, damage our relationships with customers and otherwise adversely affect our business and operating results.

Our operation of two wholly-owned packaging and testing facilities are subject to risks that could adversely affect our business and financial results.

We have two wholly-owned packaging and testing facilities located in Shanghai, China that handle most of our packaging and testing requirements. The operation of high-volume packaging and testing facilities and implementation of our advanced packaging technology are complex and demand a high degree of precision and may require modification to improve yields and product performance. We have committed substantial resources to ensure that our packaging and testing facilities operate efficiently and successfully, including the acquisition of equipment and raw materials, and training and management of a large number of technical personnel and employees. Due to the fixed costs associated with operating our own packaging and testing facilities, if we are unable to utilize our in-house facilities at a desirable level of production, our gross margin and results of operations may be adversely affected. For example, a significant decline in our market share or sales orders may negatively impact our factory utilization and reduce our ability to achieve profitability.

In addition, the operation of our packaging and testing facilities is subject to a number of risks, including the following:

Any of the foregoing risks could adversely affect our capacity to package and test our products, which could delay shipment of our products, result in higher expenses, reduce revenue, damage our relationships with customers and otherwise adversely affect our business, results of operations, financial condition and prospects.

Our reliance on distributors to sell a substantial portion of our products subjects us to a number of risks.

We sell a substantial portion of our products to distributors, who in turn sell to our end customers. Our distributors typically offer power semiconductor products from several different companies, including our direct competitors. The distributors assume collection risk and provide logistical services to end customers, including stocking our products. Two distributors, WPG and Promate, collectively accounted for 63.5% , 62.7% and 61.0% of our revenue for the fiscal years ended June 30, 2018 , 2017 and 2016 , respectively. Our agreements with Promate and WPG were renewed in July 2017 and are automatically renewed for each one-year period continuously unless terminated earlier pursuant to the provisions in the agreements. We believe that our success will continue to depend upon these distributors. Our reliance on distributors subjects us to a number of risks, including:

If any significant distributor becomes unable or unwilling to promote and sell our products, or if we are not able to renew our contracts with the distributors on acceptable terms, we may not be able to find a replacement distributor on reasonable terms or at all and our business could be harmed.

We have made and may continue to make strategic acquisitions of other companies, assets or businesses and these acquisitions introduce significant risks and uncertainties, including risks related to integrating the acquired assets or businesses, incurring additional debt, assuming contingent liabilities or diluting our existing shareholders.

In order to position ourselves to take advantage of growth opportunities, we have made, and may continue to make, strategic acquisitions, mergers and alliances that involve significant risks and uncertainties. Successful acquisitions and alliances in the semiconductor industry are difficult to accomplish because they require, among other things, efficient integration and aligning of product offerings and manufacturing operations and coordination of sales and marketing and research and development efforts. The difficulties of integration and alignment may be increased by the necessity of coordinating geographically separated organizations, the complexity of the technologies being integrated and aligned and the necessity of integrating personnel with disparate business backgrounds and combining different corporate cultures. Furthermore, there is no guarantee that we will be able to identify a viable target for strategic acquisition, and we may incur significant costs and resources in such effort that may not result in a successful acquisition.

In addition, we may also issue equity securities to pay for future acquisitions or alliances, which could be dilutive to existing shareholders. We may also incur debt or assume contingent liabilities in connection with acquisitions and alliances, which could impose restrictions on our business operations and harm our operating results.

If we are unable to obtain raw materials in a timely manner or if the price of raw materials increases significantly, production time and product costs could increase, which may adversely affect our business.

Our fabrication and packaging processes depend on raw materials such as silicon wafers, gold, copper, molding compound, petroleum and plastic materials and various chemicals and gases. From time to time, suppliers may extend lead times, limit supplies or increase prices due to capacity constraints or other factors. If the prices of these raw materials rise significantly, we may be unable to pass on the increased cost to our customers. Our results of operations could be adversely affected if we are unable to obtain adequate supplies of raw materials in a timely manner or at reasonable price. In addition, from time to time, we may need to reject raw materials because they do not meet our specifications or the sourcing of such materials do not comply with our conflict mineral policies, resulting in potential delays or declines in output. Furthermore, problems with our raw materials may give rise to compatibility or performance issues in our products, which could lead to an increase in customer returns or product warranty claims. Errors or defects may arise from raw materials supplied by third parties that are beyond our detection or control, which could lead to additional customer returns or product warranty claims that may adversely affect our business and results of operations.

Our operations may be delayed or interrupted and our business may be adversely affected as a result of our efforts to comply with environmental regulations applicable to our in-house wafer manufacturing, packaging and testing facility.

Our in-house manufacturing operations, including wafer manufacturing, packaging and testing, are subject to a variety of environmental regulations relating to the use, handling, discharge and disposal of toxic or otherwise hazardous materials. See "Item 1. Business - Environmental matters." Compliance with environmental regulations could require us to acquire expensive pollution control equipment or to incur other substantial expenses or investigate and remediate contamination at our current facilities. Any failure, or any claim that we have failed, to comply with these regulations could cause delays in our production and capacity expansion and affect our public image, either of which could harm our business. In addition, any failure to comply with these regulations could subject us to substantial fines or other liabilities, result in the suspension of our operating permit, or require us to terminate or adversely modify our in-house manufacturing operations.

We may not be able to accurately estimate provisions at fiscal period end for price adjustment and stock rotation rights under our agreements with distributors, and our failure to do so may impact our operating results.

We sell a majority of our products to distributors under arrangements allowing price adjustments and returns under stock rotation programs, subject to certain limitations. As a result, we are required to estimate allowances for price adjustments and stock rotation for our products as inventory at distributors at each reporting period end. Our ability to reliably estimate these allowances enables us to recognize revenue upon delivery of goods to distributors instead of upon resale of goods by distributors to end customers.

We estimate the allowance for price adjustment based on factors such as distributor inventory levels, pre-approved future distributor selling prices, distributor margins and demand for our products. Our estimated allowances for price adjustments, which we offset against accounts receivable from distributors, were $18.9 million and $19.6 million at June 30, 2018 and 2017 , respectively.

Our accruals for stock rotation are estimated based on historical returns and individual distributor agreement, and stock rotation rights, which are recorded as accrued liabilities on our consolidated balance sheets, are contractually capped based on the terms of each individual distributor agreement. Our estimated liabilities for stock rotation at June 30, 2018 and 2017 were $1.8 million and $1.9 million , respectively.

Our estimates for these allowances and accruals may be inaccurate. If we subsequently determine that any allowance and accrual based on our estimates is insufficient, we may be required to increase the size of our allowances and accrual in future periods, which would adversely affect our results of operations and financial condition.

We depend on the continuing services of our senior management team and other key personnel, and if we lose a member of our senior management or are unable to successfully retain, recruit and train key personnel, our ability to develop and market our products could be harmed.

Our success depends upon the continuing services of members of our senior management team and various engineering and other technical personnel. In particular, our engineers and other sales and technical personnel are critical to our future technological and product innovations. Our industry is characterized by high demand and intense competition for talent and the pool of qualified candidates is limited. We have entered into employment agreements with certain senior executives, but we do not have employment agreements with most of our employees. Many of these employees could leave our company with little or no prior notice and would be free to work for a competitor. If one or more of our senior executives or other key personnel are unable or unwilling to continue in their present positions, we may not be able to replace them easily or at all and other senior management may be required to divert attention from other aspects of our business. In addition, we do not have "key person" life insurance policies covering any member of our management team or other key personnel. The loss of any of these individuals or our inability to attract or retain qualified personnel, including engineers and others, could adversely affect our product introductions, overall business growth prospects, results of operations and financial condition.

Failure to protect our patents and our other proprietary information could harm our business and competitive position.

Our success depends, in part, on our ability to protect our intellectual property. We rely on a combination of patent, copyright (including mask work protection), trademark and trade secret laws, as well as nondisclosure agreements, license agreements and other methods to protect our intellectual property rights, which may not be sufficient to protect our intellectual property. As of June 30, 2018 , we owned 722 issued U.S. patents expiring between 2018 and 2037 and had 108 pending patent applications with the United States Patent and Trademark Office. In addition, we own additional patents and have filed patent applications in several jurisdictions outside of the U.S, including China, Taiwan, Japan and Korea.

Our patents and patent applications may not provide meaningful protection from our competitors, and there is no guarantee that patents will be issued from our patent applications. The status of any patent or patent application involves complex legal and factual determinations and the breadth of a claim is uncertain. In addition, our efforts to protect our intellectual property may not succeed due to difficulties and risks associated with:

We also rely on customary contractual protection with our customers, suppliers, distributors, employees and consultants, and we implement security measures to protect our trade secrets. We cannot assure you that these contractual protections and

security measures will not be breached, that we will have adequate remedies for any such breach or that our suppliers, employees, distributors or consultants will not assert rights to intellectual property arising out of such contracts.

In addition, we have a number of third-party patent and intellectual property license agreements, one of which requires us to make ongoing royalty payments. In the future, we may need to obtain additional licenses, renew existing license agreements or otherwise replace existing technology. We are unable to predict whether these license agreements can be obtained or renewed or the technology can be replaced on acceptable terms, or at all.

Intellectual property disputes could result in lengthy and costly arbitration, litigation or licensing expenses or prevent us from selling our products.

As is typical in the semiconductor industry, we or our customers may receive claims of infringement from time to time or otherwise become aware of potentially relevant patents or other intellectual property rights held by other parties that may cover some of our technology, products and services or those of our end customers. The semiconductor industry is characterized by vigorous protection and pursuit of intellectual property rights which has resulted in protracted and expensive arbitration and litigation for many companies. Patent litigation has increased in recent years due to increased assertions made by intellectual property licensing entities or non-practicing entities and increasing competition and overlap of product functionality in our markets.

Any litigation or arbitration regarding patents or other intellectual property could be costly and time consuming and could divert our management and key personnel from our business operations. We have in the past and may from time to time in the future become involved in litigation that requires our management to commit significant resources and time. In addition, as part of our strategy to diversify our serviceable markets, we launched several key product families and technologies to enable high efficiency power conversion solutions and we plan to develop and commercialize new products in other power semiconductor markets. Our entry into the commercial markets for high-voltage power semiconductors and other markets as a result of our diversification strategy may subject us to additional and increased risk of disputes or litigation relating to these products.

Because of the complexity of the technology involved and the uncertainty of litigation generally, any intellectual property arbitration or litigation involves significant risks. Any claim of intellectual property infringement against us may require us to:

Any intellectual property claim or litigation could harm our business, results of operations, financial condition and prospects.

Global or regional economic, political and social conditions could adversely affect our business and operating results.

External factors such as potential terrorist attacks, acts of war, financial crises, such as the global or regional economic recession, or geopolitical and social turmoil in those parts of the world that serve as markets for our products could have significant adverse effect on our business and operating results in ways that cannot presently be predicted. Any future economic downturn or recession in the global economy in general and, in particular, on the economies in China, Taiwan and other countries where we market and sell our products, will have an adverse effect on our results of operations.

Our business operations could be significantly harmed by natural disasters or global epidemics.

We have research and development facilities located in Taiwan and the Silicon Valley in Northern California. Historically, these regions have been vulnerable to natural disasters and other risks, such as earthquakes, fires and floods,

which may disrupt the local economy and pose physical risks to our property. We also have sales offices located in Taiwan and Japan where similar natural disasters and other risks may disrupt the local economy and pose physical risks to our operations. We are not currently covered by insurance against business disruption caused by earthquakes. In addition, we currently do not have redundant, multiple site capacity in the event of a natural disaster or other catastrophic event. In the event of such an occurrence, our business would suffer.

Our business could be adversely affected by natural disasters such as epidemics, outbreaks or other health crisis. An outbreak of avian flu or H1N1 flu in the human population, or another similar health crisis, could adversely affect the economies and financial markets of many countries, particularly in Asia. Moreover, any related disruptions to transportation or the free movement of persons could hamper our operations and force us to close our offices temporarily.

The occurrence of any of the foregoing or other natural or man-made disasters could cause damage or disruption to us, our employees, operations, distribution channels, markets and customers, which could result in significant delays in deliveries or substantial shortages of our products and adversely affect our business results of operations, financial condition or prospects.

Our insurance may not cover all losses, including losses resulting from business disruption or product liability claims.

We have limited product liability, business disruption or other business insurance coverage for our operations. In addition, we do not have any business insurance coverage for our operations to cover losses that may be caused by litigation or natural disasters. Any occurrence of uncovered loss could harm our business, results of operations, financial condition and prospects.

We may be adversely affected by any disruption in our information technology systems.

Our operations are dependent upon our information technology systems, which encompass all of our major business functions across offices internationally. We rely upon such information technology systems to manage and replenish inventory, complete and track customer orders, coordinate sales activities across all of our products and services, maintain vital data and information, perform financial and accounting tasks and manage and perform various administrative and human resources functions. A substantial disruption in our information technology systems for any extended time period (arising from, for example, system capacity limits from unexpected increases in our volume of business, outages or delays in our service) could result in delays in receiving inventory and supplies or filling customer orders and adversely affect our customer service and relationships. Our systems might be damaged or interrupted by natural or man−made events or by computer viruses, physical or electronic break−ins, cyber attacks and similar disruptions affecting the global Internet. There can be no assurance that such delays, problems, or costs will not have a material adverse effect on our cash flows, results of operations and financial condition.

Our international operations subject our company to risks not faced by companies without international operations.

We have adopted a global business model under which we maintain significant operations and facilities through our subsidiaries located in the U.S., China, Taiwan and Hong Kong. Our main research and development center is located in Silicon Valley, and our manufacturing and supply chain is located in China. We also have sales offices and customers throughout Asia, the U.S. and elsewhere in the world. Our international operations may subject us to the following risks:

If we fail to maintain an effective system of internal control over financial reporting, we may not be able to accurately report our financial results or prevent fraud.

Our management may conclude that our internal control over financial reporting is not effective. Moreover, even if our management concludes that our internal control over financial reporting is effective, our independent registered public accounting firm may decline to issue an opinion as to the effectiveness of our internal control over financial reporting, or may

issue a report that is qualified or adverse. During the course of the initial evaluation of internal control over financial reporting, we or our independent registered public accounting firm may identify control deficiencies that we may not be able to remediate prior to the date of our first assessment of internal control over financial reporting. Our failure to achieve and maintain effective internal control over financial reporting could result in the loss of investor confidence in the reliability of our financial statements or prevent fraud, which in turn could harm our business and negatively impact the trading price of our shares.

We are subject to the risk of increased income taxes and changes in existing tax rules.

We conduct our business in multiple jurisdictions, including Hong Kong, Macau, the U.S., China, Taiwan, South Korea Japan and Germany. The calculation of our tax liabilities involves dealing with uncertainties in the application of complex tax laws and regulations in various taxing jurisdictions. Any of these jurisdictions may assert that we have unpaid taxes. Our effective tax rate was 12.5% , 28.3% and 406.6% for the fiscal years ended June 30, 2018 , 2017 and 2016 , respectively. Any tax rate changes in the tax jurisdictions in which we operate could result in adjustments to our deferred tax assets, if applicable, which would affect our effective tax rate and results of operations. We base our tax position upon the anticipated nature and conduct of our business and upon our understanding of the tax laws of the various countries in which we have assets or conduct activities. However, our tax position is subject to review and possible challenge by tax authorities and to possible changes in law, which may have a retroactive effect. In particular, various proposals over the years have been made to change certain U.S. tax laws relating to foreign entities with U.S. connections. In addition, the U.S. government has proposed various other changes to the U.S. international tax system, certain of which could adversely impact foreign-based multinational corporate groups, and increased enforcement of U.S. international tax laws. It is possible that these or other changes in the U.S. tax laws, foreign tax laws, or proposed actions by international bodies such as the Organization of Economic Cooperation and Development (OECD) could significantly increase our U.S. or foreign income tax liability in the future. We summarize below our initial analysis of the impact of the recently enacted U.S. Tax Cuts and Jobs Act (see below section titled "U.S. Tax Cuts and Jobs Act, Enacted December 22, 2017").

In addition, our subsidiaries provide products and services to, and may from time to time undertake certain significant transactions with, us and other subsidiaries in different jurisdictions. We have adopted transfer pricing arrangements for transactions among our subsidiaries. Related party transactions are generally subject to close review by tax authorities, including requirements that transactions be priced at arm's length and be adequately documented. If any tax authorities were successful in challenging our transfer pricing policies or other tax judgments, our income tax expense may be adversely affected and we could also be subject to interest and penalty charges which may harm our business, financial condition and operating results.

Our debt agreements include financial covenants that may limit our ability to pursue business and financial opportunities and subject us to risk of default.

We have entered into debt agreements with certain financial institutions, which generally require us to maintain certain financial covenants that has the effect of limiting our ability to take certain actions, including actions to incur debt, pay dividends, repurchase stock, make certain investments and capital expenditures.  These restrictions may limit our ability to pursue business and financial opportunities that are available or beneficial to us in response to changing and competitive economic environment, which may have an adverse effect on our financial conditions.  In addition, a breach of any of these financial covenants, if not waived by the lenders, could trigger an event of default under the debt agreements, which may result in the acceleration of our indebtedness or the loss of our collateral used to secure such indebtedness.

The imposition of U.S. corporate income tax on our Bermuda parent and non-U.S. subsidiaries could adversely affect our results of operations.

We believe that our Bermuda parent and non-U.S. subsidiaries each operate in a manner that they would not be subject to U.S. corporate income tax because they are not engaged in a trade or business in the United States. Nevertheless, there is a risk that the U.S. Internal Revenue Service may assert that our Bermuda parent and non-U.S. subsidiaries are engaged in a trade or business in the United States. If our Bermuda parent and non-U.S. subsidiaries were characterized as being so engaged, we would be subject to U.S. tax at regular corporate rates on our income that is effectively connected with U.S. trade or business, plus an additional 30% "branch profits" tax on the dividend equivalent amount, which is generally effectively connected income with certain adjustments, deemed withdrawn from the United States. Any such tax could materially and adversely affect our results of operations.

We may be classified as a passive foreign investment company, which could result in adverse U.S. federal income tax consequences for U.S. holders.

Based on the current and anticipated valuation of our assets and the composition of our income and assets, we do not expect to be considered a passive foreign investment company, or PFIC, for U.S. federal income tax purposes for the foreseeable future. However, we must make a separate determination for each taxable year as to whether we are a PFIC after the close of each taxable year and we cannot assure you that we will not be a PFIC for our 2018 taxable year or any future taxable year. Under current law, a non-U.S. corporation will be considered a PFIC for any taxable year if either (1) at least 75% of its gross income is passive income or (2) at least 50% of the value of its assets, generally based on an average of the quarterly values of the assets during a taxable year, is attributable to assets that produce or are held for the production of passive income. PFIC status depends on the composition of our assets and income and the value of our assets, including, among others, a pro rata portion of the income and assets of each subsidiary in which we own, directly or indirectly, at least 25% by value of the subsidiary's equity interests, from time to time. Because we currently hold and expect to continue to hold a substantial amount of cash or cash equivalents, and because the calculation of the value of our assets may be based in part on the value of our common shares, which may fluctuate considerably given that market prices of technology companies historically often have been volatile, we may be a PFIC for any taxable year. If we were treated as a PFIC for any taxable year during which a U.S. holder held common shares, certain adverse U.S. federal income tax consequences could apply for such U.S. holder.

Risks Related to Our Industry

The average selling prices of products in our markets have historically decreased rapidly and will likely do so in the future, which could harm our revenue and gross margins.

As is typical in the semiconductor industry, the average selling price of a particular product has historically declined significantly over the life of the product. In the past, we have reduced the average selling prices of our products in anticipation of future competitive pricing pressures, new product introductions by us or our competitors and other factors. We expect that we will have to similarly reduce prices in the future for older generations of products. Reductions in our average selling prices to one customer could also impact our average selling prices to all customers. A decline in average selling prices would harm our gross margins for a particular product. If not offset by sales of other products with higher gross margins, our overall gross margins may be adversely affected. Our business, results of operations, financial condition and prospects will suffer if we are unable to offset any reductions in our average selling prices by increasing our sales volumes, reducing our costs and developing new or enhanced products on a timely basis, with higher selling prices or gross margins.

We may be adversely affected by the cyclicality of the semiconductor industry.

Our industry is highly cyclical and is characterized by constant and rapid technological change such as the introduction of smart phones and tablets that contributed to the decline in the PC market, product obsolescence and price erosion, evolving standards, uncertain product life cycles and wide fluctuations in product supply and demand. The industry has, from time to time, experienced significant and sometimes prolonged, downturns, and often connected with or in anticipation of, maturing product cycles and declines in general economic conditions. These downturns have been characterized by diminished product demand, production overcapacity, high inventory levels and accelerated erosion of average selling prices. Any future downturns, in particular the PC markets or in any other markets in which we sell our products, may reduce our revenue and result in us having excess inventory. By contrast, any upturn in the semiconductor industry could result in increased competition for access to limited third-party foundry and packaging and testing capacity, which could prevent us from benefiting from such an upturn or reduce our profit margins.

Changes in industry standards, technology, customer requirements and government regulation could limit our ability to sell our products.

The semiconductor industry is characterized by changing demand for new and advanced functions, long design and sales cycles, rapid product obsolescence and price erosion, intense competition, evolving industry standards and wide fluctuations in product supply and demand. Changes in industry standards, or the development of new industry standards, or, when applicable, government approval or disapproval of industry standards may make our products obsolete or negate the cost advantages we believe we have in our products. We may be required to invest significant effort and to incur significant expense to redesign our products in order to address relevant standards, technological developments, customer requirements or regulations but may not have the financial resources to respond to these changes effectively or in a timely manner. Any inability to meet these standards, regulations and requirements could harm our business, results of operations, financial condition and prospects.

Risks Related to Doing Business in China

China's economic, political and social conditions, as well as government policies, could affect our business and growth.

Our financial results have been, and are expected to continue to be, affected by the economy in China. If China's economy is slowing down, it may negatively affect our business operation and financial results. The China economy differs from the economies of most developed countries in many respects, including:

The Chinese economy has been transitioning from a planned economy to a more market-oriented economy. Although in recent years the China government has implemented measures emphasizing the utilization of market forces for economic reform, the reduction of state ownership of productive assets and the establishment of corporate governance in business enterprises, the China government continues to retain significant control over the business and productive assets in China. Any changes in China's government policy or China's political, economic and social conditions, or in relevant laws and regulations, may adversely affect our current or future business, results of operations or financial condition. These changes in government policy may be implemented through various means, including changes in laws and regulations, implementation of anti-inflationary measures, change of basic interest rate, changes in the tax rate or taxation system and the imposition of additional restrictions on currency conversion and imports. Furthermore, given China's largely export-driven economy, any changes in the economies of the China's principal trading partners and other export-oriented nations may adversely affect our business, results of operations, financial condition and prospects.

Our ability to successfully expand our business operations in China depends on a number of factors, including macroeconomic and other market conditions, and credit availability from lending institutions. In response to the recent global and Chinese economic recession, the China government has promulgated several measures aimed at expanding credit and stimulating economic growth. We cannot assure you that the various macroeconomic measures, monetary policies and economic stimulus package adopted by the China government to guide economic growth will be effective in maintaining or sustaining the growth rate of the Chinese economy. If measures adopted by the China government fail to achieve further growth in the Chinese economy, it may adversely affect our growth, business strategies and operating results. In addition, changes in political and social conditions of China may adversely affect our ability to conduct our business in the region. For example, geopolitical disputes and increased tensions between China and its neighboring countries in which we conduct business could make it more difficult for us coordinate and manage our international operations in such countries.

Changes in China's laws, legal protections or government policies on foreign investment in China may harm our business.

Our business and corporate transactions, including our operations through the JV Company, are subject to laws and regulations applicable to foreign investment in China as well as laws and regulations applicable to foreign-invested enterprises. These laws and regulations frequently change, and their interpretation and enforcement involves uncertainties that could limit the legal protections available to us. Regulations and rules on foreign investments in China impose restrictions on the means that a foreign investor like us may apply to facilitate corporate transactions we may undertake. In addition, the Chinese legal system is based in part on government policies and internal rules, some of which are not published on a timely basis or at all, that may have a retroactive effect. As a result, we may not be aware of our violation of these policies and rules until sometime after the violation. If any of our past operations are deemed to be non-compliant with Chinese law, we may be subject to penalties and our business and operations may be adversely affected. For instance, under the catalogue for the Guidance of Foreign Investment Industries, some industries are categorized as sectors which are encouraged, restricted or prohibited for foreign investment. As the catalogue for the Guidance of Foreign Investment Industries is updated every few years, there can be no assurance that the China government will not change its policies in a manner that would render part or all of our business to fall within the restricted or prohibited categories. If we cannot obtain approval from relevant authorities to engage in businesses which become prohibited or restricted for foreign investors, we may be forced to sell or restructure a business which has become restricted or prohibited for foreign investment. Furthermore, the China government has broad discretion in dealing with violations of laws and regulations, including levying fines, revoking business and other licenses and requiring actions necessary for compliance. In particular, licenses and permits issued or granted to us by relevant governmental bodies may be revoked at a later time by higher regulatory bodies. If we are forced to adjust our corporate structure or business as a result of changes in government policy on foreign investment or changes in the interpretation and

application of existing or new laws, our business, financial condition, results of operations and prospects may be harmed. Moreover, uncertainties in the Chinese legal system may impede our ability to enforce contracts with our business partners, customers and suppliers, or otherwise pursue claims in litigation to recover damages or loss of property, which could adversely affect our business and operations.

Substantial uncertainties exist with respect to the enactment timetable, interpretation and implementation of draft PRC Foreign Investment Law and how it may impact the viability of our current corporate structure, corporate governance and business operations.

The Ministry of Commerce (MOC) published a discussion draft of the proposed Foreign Investment Law in January 2015 aiming to, upon its enactment, replace the trio of existing laws regulating foreign investment in China, namely, the Sino-foreign Equity Joint Venture Enterprise Law, the Sino-foreign Cooperative Joint Venture Enterprise Law and the Wholly Foreign-invested Enterprise Law, together with their implementation rules and ancillary regulations. The draft Foreign Investment Law embodies an expected PRC regulatory trend to rationalize its foreign investment regulatory regime in line with prevailing international practice and the legislative efforts to unify the corporate legal requirements for both foreign and domestic investments. The MOC is currently soliciting comments on this draft and substantial uncertainties exist with respect to its enactment timetable, interpretation and implementation. On September 3, 2016, the Standing Committee of China's National People's Congress, passed the Decision on Amendment of Four Laws including the Foreign-Invested Enterprise Law, or the FIE Amendment, which was implemented starting on October 1, 2016. According to the FIE Amendment, establishment and changes of an FIE in a sector not subject to special entry administrative measures will be simplified by going through government filing instead of government approval process. The special entry administrative measures will be separately promulgated or approved to be promulgated by the State Council. Subsequently, the National Development and Reform Commission and MOC issued the Announcement 2016 No. 22 on October 8, 2016, which provides that the special entry administrative measures shall be implemented with reference to the relevant requirement on equity percentage and senior management in relation to the restricted foreign investment industries, prohibited foreign investment industries and encouraged foreign investment industries as stipulated in the Catalogue for the Guidance of Foreign Investment Industries. Further, the MOC published the Provisional Measures on Filing Administration for Establishment and Change of Foreign-Invested Enterprises on October 8, 2016, which implements and elaborates the procedures, supervision and related matters of the filings for formation and changes of foreign-invested enterprises in a sector not subject to special entry administrative measures. The draft Foreign Investment Law, if enacted as proposed, may materially impact the viability of our current corporate structure, corporate governance and business operations in many aspects.

The draft Foreign Investment Law, if enacted as proposed, may also materially impact our corporate governance practice and increase our compliance costs. For instance, the draft Foreign Investment Law imposes stringent ad hoc and periodic information reporting requirements on foreign investors and the applicable foreign invested entities. Aside from an investment implementation report and an investment amendment report that are required for each investment and alteration of investment specifics, an annual report is mandatory, and large foreign investors meeting certain criteria are required to report on a quarterly basis. Any company found to be non-compliant with these information reporting obligations may potentially be subject to fines and/or administrative or criminal liabilities, and the persons directly responsible may be subject to criminal liabilities.

Limitations on our ability to transfer funds to our China subsidiaries could adversely affect our ability to expand our operations, make investments that could benefit our businesses and otherwise fund and conduct our business.

The transfer of funds from us to our China subsidiaries, either as a shareholder loan or as an increase in registered capital, is subject to registration with or approval by the China's governmental authorities, including the State Administration of Foreign Exchange, or SAFE, or the relevant examination and approval authority. Our subsidiaries may also experience difficulties in converting our capital contributions made in foreign currencies into RMB due to changes in the China's foreign exchange control policies. Therefore, it may be difficult to change capital expenditure plans once the relevant funds have been remitted from us to our China subsidiaries. These limitations and the difficulties our China subsidiaries may experience on the free flow of funds between us and our China subsidiaries could restrict our ability to act in response to changing market situations in a timely manner.

China's currency exchange control and government restrictions on investment repatriation may impact our ability to transfer funds outside of China.

A significant portion of our business is conducted in China where the currency is the Renminbi. Regulations in China permit foreign owned entities to freely convert the Renminbi into foreign currency for transactions that fall under the "current account," which includes trade related receipts and payments, interest and dividends. Accordingly, our Chinese subsidiaries may use Renminbi to purchase foreign exchange for settlement of such "current account" transactions without pre-approval. However, pursuant to applicable regulations, foreign‑invested enterprises in China may pay dividends only out of their

accumulated profits, if any, determined in accordance with Chinese accounting standards and regulations. In calculating accumulated profits, foreign investment enterprises in China are required to allocate at least 10% of their accumulated profits each year, if any, to fund certain reserve funds, including mandated employee benefits funds, unless these reserves have reached 50% of the registered capital of the enterprises.

Other transactions that involve conversion of Renminbi into foreign currency are classified as "capital account" transactions; examples of "capital account" transactions include repatriations of investment by or loans to foreign owners, or direct equity investments in a foreign entity by a China domiciled entity. "Capital account" transactions require prior approval from China's State Administration of Foreign Exchange (SAFE) or its provincial branch to convert a remittance into a foreign currency, such as U.S. dollars, and transmit the foreign currency outside of China.

As a result of these and other restrictions under PRC laws and regulations, our China subsidiaries are restricted in their abil ity to transfer a portion of their net assets to the parent; such restricted portion amounted to approximate ly $279.6 million, or 65.6% of our total consolidated net assets as of June 30, 2018 . We have no assurance that the relevant Chinese governmental authorities in the future will not limit further or eliminate the ability of our China subsidiaries to purchase foreign currencies and transfer such funds to us to meet our liquidity or other business needs. Any inability to access funds in China, if and when needed for use by the Company outside of China, could have a material and adverse effect on our liquidity and our business.

The M&A Rules and certain other PRC regulations establish complex procedures for some acquisitions of Chinese companies by foreign investors, which could make it more difficult for us to pursue growth through acquisitions in China.

The Regulations on Mergers and Acquisitions of Domestic Companies by Foreign Investors, or the M&A Rules, adopted by six PRC regulatory agencies in August 2006 and amended in 2009, and some other regulations and rules concerning mergers and acquisitions established additional procedures and requirements that could make merger and acquisition activities by foreign investors more time consuming and complex, including requirements in some instances that the MOC be notified in advance of any change-of-control transaction in which a foreign investor takes control of a PRC domestic enterprise. Moreover, the Anti-Monopoly Law requires that the MOC shall be notified in advance of any concentration of undertaking if certain thresholds are triggered. In addition, the security review rules issued by the MOC that became effective in September 2011 specify that mergers and acquisitions by foreign investors that raise "national defense and security" concerns and mergers and acquisitions through which foreign investors may acquire de facto control over domestic enterprises that raise "national security" concerns are subject to strict review by the MOC, and the rules prohibit any activities attempting to bypass a security review, including by structuring the transaction through a proxy or contractual control arrangement. In the future, we may grow our business by acquiring complementary businesses. Complying with the requirements of the above-mentioned regulations and other relevant rules to complete such transactions could be time consuming, and any required approval processes, including obtaining approval from the MOC or its local counterparts may delay or inhibit our ability to complete such transactions, which could affect our ability to expand our business or maintain our market share.

Our results of operations may be negatively impacted by fluctuations in foreign currency exchange rates between U.S. dollars and Chinese Yuan, or RMB.

While U.S. dollars is our main functional currency and our revenue and a significant portion of our operating expenses are denominated in U.S. dollars, we are required to maintain local currencies, primarily the RMB, in our cash balances in connection with the funding of our oversea operations.  As a result, our costs and operating expenses may be exposed to adverse movements in foreign currency exchange rates between the U.S. dollars and RMB.  We also do not utilize any financial instruments to hedge or reduce potential losses due to the fluctuation of foreign currency exchange rates.  In general, any appreciation of U.S. dollars against a weaker RMB could reduce the value of our cash and cash equivalent balance, which could increase our operating expenses and negatively affect our cash flow, income and profitability.  The value of RMB against the U.S. dollars may fluctuate and is affected by many factors outside of our control, including changes in political and economic conditions, implementation of new monetary policies by the Chinese government and changes in banking regulations, and there is no guarantee that we will be able to mitigate or recoup any losses due to a significant fluctuation in the U.S. dollars/RMB exchange rates.

PRC labor laws may adversely affect our results of operations.

On June 29, 2007, the PRC government promulgated the Labor Contract Law of the PRC, effective on January 1, 2008, to govern the establishment of employment relationships between employers and employees, and the conclusion, performance, termination of and the amendment to employment contracts. The Labor Contract Law imposes greater liabilities on employers and significantly affects the cost of an employer's decision to reduce its workforce. Further, it requires that certain

terminations be based upon seniority and not merit. In the event our subsidiaries decide to significantly change or decrease their workforce in China, the Labor Contract Law could adversely affect their ability to effect such changes in a manner that is most advantageous to our business or in a timely and cost-effective manner, thus materially and adversely affecting our financial condition and results of operations.

In recent years, compensation in various industries in China has increased and may continue to increase in the future. In order to attract and retain skilled personnel, we may need to increase the compensation of our employees. Compensation may, also, increase as inflationary pressure increases in China. In addition, under the Regulations on Paid Annual Leave for Employees, which became effective on January 1, 2008, employees who have served more than one year for a specific employer are entitled to a paid vacation ranging from 5 to 15 days, depending on length of service. Employees who waive such vacation time at the request of employers must be compensated for three times their normal salaries for each waived vacation day. This mandated paid-vacation regulation, coupled with the trend of increasing compensation, may result in increase in our employee-related costs and expenses and decrease in our profit margins.

Controversies affecting China's trade with the United States could harm our business.

Controversies between the United States and China may arise that threaten the trading relationship between the two countries. At various times during recent years, the United States and China have had disagreements over political and economic issues, including the recent imposition of tariffs by U.S. against goods imported from China. See risk factor on page 14 entitled "Possible new tariffs on imported goods from China could adversely affect our business operations" above. In addition, disagreements between the United States and China with respect to their political, military or economic policies toward Taiwan may contribute to further controversies. These controversies and trade frictions could have a material adverse effect on our business by, among other things, making it more difficult for us to coordinate our operations between the United States and China or causing a reduction in the demand for our products by customers in the United States or China.

Relations between Taiwan and China could negatively affect our business, financial condition and operating results and, therefore, the market value of our common shares.

Taiwan has a unique international political status. China does not recognize the sovereignty of Taiwan. Although significant economic and cultural relations have been established during recent years between Taiwan and China, relations have often been strained. A substantial number of our key customers and some of our essential sales and engineering personnel are located in Taiwan, and we have a large number of operational personnel and employees located in China. Therefore, factors affecting military, political or economic relationship between China and Taiwan could have an adverse effect on our business, financial condition and operating results.

Risks Related to Our Corporate Structure and Our Common Shares

Our share price may be volatile and you may be unable to sell your shares at or above the purchase price, if at all.

Limited trading volumes and liquidity of our common shares on the NASDAQ Global Select Market may limit the ability of shareholders to purchase or sell our common shares in the amounts and at the times they wish.  In addition, the financial markets in the United States and other countries have experienced significant price and volume fluctuations, and market prices of technology companies have been and continue to be extremely volatile. The trading price of our common shares on The NASDAQ Global Select Market ranged from a low of $6.83 to high of $23.43 from the commencement of the public trading of our common shares on April 29, 2010, to July 31, 2018 and from a low of $13.94 to high of $18.62 from July 1, 2017 to June 30, 2018 . At July 31, 2018, the trading price of our common shares was $13.36. Volatility in the price of our shares may be caused by factors outside our control and may be unrelated or disproportionate to our operating results.

The market price for our common shares may be volatile and subject to wide fluctuations in response to factors, including:

In the past, securities class action litigation has often been brought against a company following periods of volatility in such company's share price.  This type of litigation could result in substantial costs and divert our management's attention and resources which could negatively impact our business and financial conditions.

If securities or industry analysts do not publish research or reports about our business, or if they adversely change their recommendations regarding our common shares or if our operating results do not meet their expectations, the trading price of our common shares could decline.

The market price of our common shares is influenced by the research and reports that industry or securities analysts publish about us or our business. There is no guarantee that these analysts will understand our business and results, or that their reports will be accurate or correctly predict our operating results or prospects. If one or more of these analysts cease coverage of our company or fail to publish reports on us regularly, we could lose visibility in the financial markets, which in turn could cause the market price of our common shares or its trading volume to decline. Moreover, if one or more of the analysts who cover our company downgrade our common shares or if our operating results or prospects do not meet their expectations, the market price of our common shares could decline significantly.

Anti-takeover provisions in our bye-laws could make an acquisition of us more difficult and may prevent attempts by our shareholders to replace or remove our current management.

Certain provisions in our bye-laws may delay or prevent an acquisition of us or a change in our management. In addition, by making it more difficult for shareholders to replace members of our board of directors, these provisions also may frustrate or prevent any attempts by our shareholders to replace or remove our current management because our board of directors is responsible for appointing the members of our management team. These provisions include:

These provisions could make it more difficult for a third-party to acquire us, even if the third-party's offer may be considered beneficial by many shareholders. As a result, shareholders may be limited in their ability to obtain a premium for their shares.

Insiders have substantial control over us, which could adversely affect the market price of our shares.

Our Chief Executive Officer, certain members of our management and directors, beneficially owned, in the aggregate, approximately 21.2% of our outstanding common shares as of June 30, 2018 . As a result, these shareholders will be able to exert significant control over all matters requiring shareholder approval, including the election of directors and approval of significant corporate transactions, such as a merger, consolidation, takeover or other business combination involving us. This concentration of ownership may also discourage, delay or prevent a change in control of our company, which could deprive our shareholders of an opportunity to receive a premium for their shares as part of a sale of our company and may reduce the trading price of our shares. Furthermore, the interests of these insiders could conflict with the interests of our other shareholders and, accordingly, any of them may take actions that favor their own interests and which may not be in the best interests of our other shareholders. These actions may be taken even if they are opposed by our other shareholders.

We are a Bermuda company and the rights of shareholders under Bermuda law may be different from U.S. laws.

We are a Bermuda limited liability exempted company. As a result, the rights of holders of our common shares will be governed by Bermuda law and our memorandum of association and bye-laws.  The rights of shareholders under Bermuda law may differ from the rights of shareholders of companies incorporated in other jurisdictions, including the U.S.  For example, some of our directors are not residents of the United States, and a substantial portion of our assets are located outside the United States.  As a result, it may be difficult for investors to effect service of process on those persons in the U.S. or to enforce in the U.S. judgments obtained in U.S. courts against us or those persons based on civil liability provisions of the U.S. securities laws.  It is doubtful whether courts in Bermuda will enforce judgments obtained in other jurisdictions, including the U.S., against us or our directors or officers under the securities laws of those jurisdictions or entertain actions in Bermuda against us or our directors or officers under the securities laws of other jurisdictions.

Item 1B.     Unresolved Staff Comments

None.

Item 2.    Properties

We believe that our current facilities are adequate and that additional space will be available on commercially reasonable terms for the foreseeable future.

We are currently not a party to any material legal proceedings. We have in the past, and may from time to time in the future, become involved in legal proceedings arising from the normal course of business activities.  The semiconductor industry is characterized by frequent claims and litigation, including claims regarding patent and other intellectual property rights as well as improper hiring practices. Irrespective of the validity of such claims, we could incur significant costs in the defense thereof or could suffer adverse effects on our operations.

Item 4.         Mine Safety Disclosures

Not Applicable.

PART II

Market Price of Our Common Shares

Our common shares have traded on the NASDAQ Global Select Market since April 29, 2010 under the symbol AOSL. The following table sets forth, for the periods indicated, the high and low sales prices of our common share as reported by the NASDAQ Global Select Market.

Holders of Our Common Shares

As of July 31, 2018 , there were approximately 116 holders of record of our common shares, not including those shares held in street or nominee name.

Dividend Policy

We have never declared or paid cash dividends on our common shares. We currently intend to retain all available funds and any future earnings for use in the operation of our business and do not anticipate paying any dividends on our common share in the foreseeable future. Any future determination to declare dividends will be made at the discretion of our board of directors and will depend on our financial condition, operating results, capital requirements, general business conditions and other factors that our board of directors may deem relevant.

Securities Authorized for Issuance Under Equity Compensation Plans

See Item 12 of Part III of this report regarding information about securities authorized for issuance under our equity compensation plans.

Share Performance Graph

The following graph compares the total cumulative shareholder return on our common shares with the total cumulative return of the NASDAQ Composite Index and the Philadelphia Semiconductor Index for the last five fiscal year ended June 30, 2018 , assuming an investment of $100 at the beginning of such period and the reinvestment of any dividends.

The comparisons in the graph below are required by the SEC and are not intended to forecast or be indicative of possible future performance of our common shares.

The above Stock Performance Graph and related information shall not be deemed "soliciting material" or to be "filed" with the Securities and Exchange Commission, nor shall such information be incorporated by reference into any future filing under the Securities Act of 1933 or Securities Exchange Act of 1934, each as amended, except to the extent that the Company specifically incorporates it by reference into such filing.

Purchases of Equity Securities by the Issuer and Affiliated Purchasers

In September 2017, the Board of Directors terminated the repurchase program that was previously approved in April 2015 and approved a new repurchase program (the "Repurchase Program"), which allows the Company to repurchase its common shares from the open market pursuant to a pre-established Rule 10b5-1 trading plan or through privately negotiated transactions up to an aggregate of $30.0 million . The amount and timing of any repurchases under the Repurchase Program depend on a number of factors, including but not limited to, the trading price, volume and availability of the Company's common shares. There is no guarantee that any repurchases under the Repurchase Program will enhance the value of our shares. Shares repurchased under this program are accounted for as treasury shares and the total cost of shares repurchased is recorded as a reduction of shareholders' equity. As of June 30, 2018 , we had $14.9 million available under this repurchase program.

The following table sets for the share repurchases under this program during the fourth quarter of fiscal year 2018:

Item 6. Selected Financial Data

We have derived the selected consolidated statements of operations data for the fiscal years ended June 30, 2018 , 2017 and 2016 and selected consolidated balance sheet data as of June 30, 2018 and 2017 from our audited consolidated financial statements and related notes included elsewhere in this report. We have derived the selected consolidated statements of operations data for the fiscal years ended June 30, 2015 and 2014 and selected consolidated balance sheets as of June 30, 2016 , 2015 and 2014 from consolidated financial statements not included in this report. The information set forth below is not necessarily indicative of results of future operations, and should be read in conjunction with Item 7, "Management's Discussion and Analysis of Financial Condition and Results of Operations" in this Annual Report on Form 10-K.

You should read the following discussion of the financial condition and results of our operations in conjunction with our consolidated financial statements and the notes to those statements included elsewhere in this annual report. Our consolidated financial statements contained in this annual report are prepared in accordance with U.S. GAAP.

Overview

We are a designer, developer and global supplier of a broad portfolio of power semiconductors. Our portfolio of power semiconductors includes approximately 1,900 products, and has grown significantly with the introduction of 200 new products during the fiscal year of 2018 , and over 80 and 90 new products in each of the fiscal years ended June 30, 2017 and 2016 , respectively. Our teams of scientists and engineers have developed extensive intellectual properties and technical knowledge that encompass major aspects of power semiconductors, which we believe enables us to introduce and develop innovative products to address the increasingly complex power requirements of advanced electronics. We have an extensive patent portfolio that consists of 722 patents and 108 patent applications in the United States as of June 30, 2018 . We differentiate ourselves by integrating our expertise in technology, design and advanced manufacturing and packaging to optimize product performance and cost. Our portfolio of products targets high-volume applications, including personal computers, flat panel TVs, LED lighting, smart phones, battery packs, consumer and industrial motor controls and power supplies for TVs, computers, servers and telecommunications equipment.

Our business model leverages global resources, including research and development and manufacturing in the United States and Asia. Our sales and technical support teams are localized in several growing markets. We operate a 8-inch wafer fabrication facility located in Hillsboro, Oregon, or the Oregon fab, which is critical for us to accelerate proprietary technology development, new product introduction and improve our financial performance in the long run. To meet the market demand for the more mature high volume products, we also utilize the wafer manufacturing capacity of selected third party foundries. For assembly and test, we primarily rely upon our in-house facilities in China. In addition, we utilize subcontracting partners for industry standard packages. We believe our in-house packaging and testing capability provides us with a competitive advantage in proprietary packaging technology, product quality, cost and sales cycle time.

On March 29, 2016, we entered into a joint venture contract (the "JV Agreement") with two investment funds owned by the Municipality of Chongqing (the "Chongqing Funds"), pursuant to which we and the Chongqing Funds formed a joint venture, (the "JV Company"), for the purpose of constructing a power semiconductor packaging, testing and wafer fabrication facility in the Liangjiang New Area of Chongqing, China (the "JV Transaction"). The total initial capitalization of the JV Company is $330.0 million (the "Initial Capitalization"). As of June 30, 2018, the Chongqing Funds contributed a total of $162.0 million of initial capital in cash and we contributed $10.0 million in cash and certain intangible assets, as well as certain packaging equipment as required by the JV Agreement by transferring the legal titles of such equipment to the JV Company. As of June 30, 2018, we own 51%, and the Chongqing Funds own 49%, of the equity interest in the JV Company. If both parties agree that the termination of the JV Company is the best interest of each party or the JV Company is bankrupt or insolvent where either party may terminate early, after paying the debts of the JV Company, the remaining assets of the JV Company shall be paid to the Chongqing Funds to cover the principal of its total paid-in contributions plus interest at 10% simple annual rate prior to distributing the balance of the JV Company's assets to us. We substantially completed our assembly and testing and 12-inch wafer fab facilities during the quarter ended June 30, 2018. We expect to commence limited mass production for assembly and testing in the second half of calendar year 2018, and trial production at the 12-inch wafer fabrication facility toward the end of calendar year 2018. During fiscal years 2018, 2017 and 2016, we recorded $9.3 million , $4.6 million and $0.1 million in net loss attributable to noncontrolling interest, respectively, representing 49% of the net loss incurred in the JV Company. In the long-term, we expect the joint venture to deliver significant cost savings, and enhance our market positions in China, and drive meaningful improvements in working capital and capital expenditures.

As part of the JV Transaction, the JV Company entered into an Engineering, Procurement and Construction Contract (the "EPC Contract") with The IT Electronics Eleventh Design & Research Institute Scientific and Technological Engineering Corporation Limited (the "Contractor"), effective as of January 10, 2017 (the "Effective Date"), pursuant which the Contractor was engaged to construct the manufacturing facility contemplated under the JV Agreement. Under the EPC Contract, the Contractor's obligations include, but are not limited to: (i) the development of conceptual design, initial design, construction drawing design and optimization, and submission of such designs to the JV Company for examination and confirmation; and (ii) the construction of the assembly and wafer fabrication facilities and related procurement services, including the selection and engagement of subcontractors, in accordance with a construction schedule agreed upon by the parties. The total price payable under the EPC Contract is Chinese Renminbi (RMB) 540.0 million, or approximately $78.0 million, based on the currency exchange rate between RMB and U.S. Dollars on the Effective Date, which consists of $2.8 million (RMB 19.5 million) of design fees ("Design Fees") and $75.2 million (RMB 520.5 million) of construction and procurement fees

(including compliance with safety and aesthetic requirements) ("Construction Fees"). The Design Fees and Construction Fees are paid by the JV Company pursuant to a payment schedule based on the progress of the construction and the achievements of specified milestones. The payment may be subject to volatility as a result of exposure to fluctuations in RMB foreign exchange rates. As of June 30, 2018 , the JV Company paid approximately $66.4 million (RMB 439.5 million ), and expects to pay the remaining of $15.2 million (RMB 100.5 million ) in fiscal year 2019.

On September 5, 2017, we entered into a license agreement with STMicroelectronics International N.V. ("STMicro"), pursuant to which STMicro granted us a world-wide, royalty-free and fully-paid license to use its technologies to develop, market and distribute certain digital multi-phase controller products, which have been previously offered by STMicro.  Under the license agreement, we agreed to pay a total price in cash of $17.0 million based on the payment schedule as set forth in the agreement of approximately $10.1 million, $6.7 million and $0.2 million in calendar year 2017, 2018 and 2019, respectively. As of June 30, 2018, we recorded $15.8 million of intangible assets related to STMicro.

During the fiscal year ended June 30, 2018 , we continued our diversification program by developing new silicon and packaging platforms to expand our serviceable available market, or SAM and offer higher performance products. Our metal-oxide-semiconductor field-effect transistors, or MOSFET, portfolio expanded significantly across a full range of voltage applications. For example, during the fourth quarter of fiscal year of 2018, we introduced new family of EZBuck™ regulators featuring I2C control. The new devices provide a compact, efficient power converter solution for next-generation chipsets and FPGAs used in high-end TVs, set-top boxes, data storage systems, servers and other embedded systems. We also introduced the AONX38168, which utilizes the latest 25V N-Channel MOSFET technology platform, combining the low-side and high-side in a leadless surface mount package to offer high power density for server and telecommunication markets. During the third quarter of fiscal year of 2018, we introduced AONE36132, a 25V N-Channel MOSFET in a compact dual DFN 3.3x3.3 package, offering lower switch node ringing and lower parasitic inductance. Also we introduced a new Type-C Power Delivery compliant load switch with up to 28V over-voltage protection. This new device offers low RDS(ON) (40mohm) in a thermally enhanced 3x3mm DFN package, making it an ideal solution for the latest notebooks, ultrabooks, desktops, monitors, dockings/dongles, and Thunderbolt/USB Type-C PD applications. During the second quarter of fiscal year of 2018, we introduced AONR21357, which uses the improved P-Channel MOSFET process to achieve low power loss and reliable startup. This new P-Channel MOSFET is ideal for load switch applications in Notebook Adapter-In/ Battery In sockets. We also released AONS66916 production utilizing the latest Alpha Shield Gate Technology Generation 2 (AlphaSGT2), which enables higher efficiency and robustness to critical high density telecom and server applications. During the first quarter of fiscal year of 2018, we released AOTF190A60L, the first product in the new AMOS5TMHV MOSFET platform.  This device provides high-efficiency performance in an easy-to-use solution optimized for server power supplies, high-end computers, charging stations and other high-performance applications.  We also introduced AOZ5131QI, the latest generation of power modules. The new device enables high power-density voltage regulator solutions ideal for CPU and GPU power regulation in notebook PCs, servers, and graphic cards. In addition, we expanded our recently launched fast turn-off switched 650V H-series IGBT family with a 1200V rating. The new AOK40B120H1 has been developed to address needs of industrial welding and high-frequency converters with 3-phase AC or high voltage DC input. The device offers excellent performance in high switching frequency applications, which can be a perfect fit for high voltage industrial welding machines.

Factors affecting our performance

Our performance is affected by several key factors, including the following:

Costs of JV Company and digital power business: We are incurring an increase in operating expenses due to the additional costs associated with ramping up pre-production activities of the JV Company, as well as the initial startup work to develop and establish our new digital power business will have the significant impact on our financial performance. We substantially completed our assembly and testing and 12-inch wafer fab facilities during the quarter ended June 30, 2018. We expect to commence limited mass production for assembly and testing in the second half of calendar year 2018, and trial production at our 12-inch wafer fabrication facility toward the end of calendar year 2018. The pre-production costs include costs relating to the installation of equipment; performance of the qualification process; increased demand for electrical power and other utilities; increased headcount as a result of hiring of additional personnel, staff and operators; and establishment of administrative and management functions and systems. In addition, a portion of these pre-production expenses and production ramp-up costs cannot be capitalized under U.S. GAAP accounting, therefore such costs impact our profitability. Furthermore, we are in the process of developing our digital power business following the execution of the STMicro license agreement in September 2017, which will allow us to design and distribute a full suite of advanced low-voltage power IC products. We have incurred and expect to continue to incur additional costs, including costs relating to hiring and compensation of qualified engineers and technical staff and other research and development and management activities, as we are building this new business. In the short term, we will not be able to generate sufficient amount of revenue from either of these two business initiatives to offset the increase costs, which will likely negatively impact our results of operations.

Manufacturing costs :  Our gross margin may be affected by our manufacturing costs, including utilization of our manufacturing facilities, pricing of wafers from third party foundries and semiconductor raw materials, which may fluctuate from time to time largely due to the market demand and supply.  Capacity utilization affects our gross margin because we have certain fixed costs associated with our packaging and testing facilities and our Oregon fab and our Chongqing fabrication facility.  If we are unable to utilize our manufacturing facilities at a desired level, our gross margin may be adversely affected.  In addition, we expect that in the long term our joint venture agreement with the Chongqing Funds will reduce our costs of manufacturing. Furthermore, from time to time, we may experience wafer capacity constraints, particularly at third party foundries, that may prevent us from fully meeting the demand of our customers. While we can mitigate such constraints by increasing and re-allocating capacity at our own fab, we may not be able to do so quickly or at sufficient level, which could adversely affect our financial conditions and results of operations.

Erosion of average selling price: Erosion of average selling prices of established products is typical in our industry. Consistent with this historical trend, we expect our average selling prices of existing products to decline in the future. However, in the normal course of business, we seek to offset the effect of declining average selling price by introducing new and higher value products, expanding existing products for new applications and new customers and reducing the manufacturing cost of existing products.

The global, regional economic and PC market conditions : Because our products primarily serve consumer electronic applications, a deterioration of the global and regional economic conditions could materially affect our revenue and results of operations. For example, because a significant amount of our revenue is derived from sales of products in the personal computing ("PC") markets, such as notebooks, motherboards and notebook battery packs, a significant decline or downturn in the PC market can have a material adverse effect on our revenue and results of operations.  Our revenue from the PC markets accounted for approximately 41.6% , 39.1% and 38.5% of our total revenue for the years ended June 30, 2018 , 2017 and 2016 , respectively. In the past, we have experienced a significant global decline in the PC markets due to continued growth of demand in tablets and smart phones, worldwide economic conditions and the industry inventory correction which had and may continue to have a material negative impact on the demand for our products, revenue, factory utilization, gross margin, our ability to resell excess inventory, and other performance measures. We have executed and continue to execute strategies to diversify our product portfolio, penetrate into other market segments, including the consumer, communications and industrial markets, and improve gross margins and profit by implementing cost control measures. While making progress in reducing our reliance on the computing market, we continue to support our computing business and capitalize on the opportunities in this market with a more focused and competitive PC product strategy.

Product introductions and customers' product requirements : Our success depends on our ability to introduce products on a timely basis that meet or are compatible with our customers' specifications and performance requirements. Both factors, timeliness of product introductions and conformance to customers' requirements, are equally important in securing design wins with our customers. As we accelerate the development of new technology platforms, we expect to increase the pace at which we introduce new products and obtain design wins. Our failure to introduce new products on a timely basis that meet customers' specifications and performance requirements, particularly those products with major OEM customers, and our inability to continue to expand our serviceable markets, could adversely affect our financial performance, including loss of market share. We believe that the JV Transaction will increase and diversify our customer base, particularly in China, in the long term. The JV Company substantially completed its assembly and testing and 12-inch wafer fab facilities during the quarter ended June 30, 2018. We expect to commence limited mass production of assembly and testing in the second half of calendar year 2018, and trial production of power semiconductors at the 12-inch wafer fabrication facility toward the end of calendar year 2018. However, we may experience delays in the commencement or ramp up of the production at the JV Company. Even if we are able to commence JV operation timely, we may not be successful in acquiring a sufficient number of new customers to offset the additional costs due to various factors, including but are not limited to, competition from other semiconductor companies in the region, our lack of history and prior relationships with customers as a new entrant, difficulties in executing our joint venture strategies, lack of control over our operations and the general economic conditions in Chongqing and China.

Distributor ordering patterns, customer demand and seasonality : Our distributors place purchase orders with us based on their forecasts of end customer demand, and this demand may vary significantly depending on the sales outlook and market and economic conditions of end customers. Because these forecasts may not be accurate, channel inventory held at our distributors may fluctuate significantly, which in turn may prompt distributors to make significant adjustments to their purchase orders placed with us. As a result, our revenue and operating results may fluctuate significantly from quarter to quarter. In addition, because our products are used in consumer electronics products, our revenue is subject to seasonality. Our sales seasonality is affected by numerous factors, including global and regional economic conditions as well as the PC market conditions, revenue generated from new products, changes in distributor ordering patterns in response to channel inventory adjustments and end

customer demand for our products and fluctuations in consumer purchase patterns prior to major holiday seasons. In recent periods, broad fluctuations in the semiconductor markets and the global and regional economic conditions, in particular the decline of the PC market conditions, have had a more significant impact on our results of operations than seasonality. Furthermore, our revenue may be impacted by the level of demand from our major customers due to factors outside of our control. If these major customers experience significant decline in the demand of their products, encounter difficulties or defects in their products, or otherwise fail to execute their sales and marketing strategies successfully, it may adversely affect our revenue and results of operations.

Principal line items of statements of income

The following describes the principal line items set forth in our consolidated statements of operations:

Revenue

We generate revenue primarily from the sale of power semiconductors, consisting of power discretes and power ICs. Historically, a majority of our revenue has been derived from power discrete products. Because our products typically have three-year to five-year life cycles, the rate of new product introduction is an important driver of revenue growth over time. We believe that expanding the breadth of our product portfolio is important to our business prospects, because it provides us with an opportunity to increase our total bill-of-materials within an electronic system and to address the power requirements of additional electronic systems. In addition, a small percentage of our total revenue is generated by providing packaging and testing services to third-parties through one of our subsidiaries.

Our product revenue is reported net of the effect of the estimated stock rotation returns and price adjustments that we expect to provide to our distributors. Stock rotation returns are governed by contract and are limited to a specified percentage of the monetary value of products purchased by the distributor during a specified period. At our discretion or upon our direct negotiations with the original design manufacturers ("ODMs") or original equipment manufacturers ("OEMs"), we may elect to grant special pricing that is below the prices at which we sold our products to the distributors. In these situations, we will grant price adjustments to the distributors reflecting such special pricing. We estimate the price adjustments for inventory at the distributors based on factors such as distributor inventory levels, pre-approved future distributor selling prices, distributor margins and demand for our products.

Cost of goods sold

Our cost of goods sold primarily consists of costs associated with semiconductor wafers, packaging and testing, personnel, including share-based compensation expense, overhead attributable to manufacturing, operations and procurement, and costs associated with yield improvements, capacity utilization, warranty and inventory reserves. As the volume of sales increases, we expect cost of goods sold to increase. We implemented a process to improve our factory capacity utilization rates by transferring more wafer production to our Oregon fab and reducing our reliance on outside foundries. While our utilization rates cannot be immune to the market conditions, our goal is to make them less vulnerable to market fluctuations. We believe our market diversification strategy and product growth will drive higher volume of manufacturing which will improve our factory utilization rates and gross margin in the long run.

Operating expenses

Our operating expenses consist of research and development, selling, general and administrative expenses and impairment of long-lived assets. We expect our operating expenses as a percentage of revenue to fluctuate from period to period as we continue to exercise cost control measures in response to the declining PC market as well as align our operating expenses to the revenue level.

Research and development expenses.  Our research and development expenses consist primarily of salaries, bonuses, benefits, share-based compensation expense, expenses associated with new product prototypes, travel expenses, fees for engineering services provided by outside contractors and consultants, amortization of software and design tools, depreciation of equipment and overhead costs. We continue to invest in developing new technologies and products utilizing our own fabrication and packaging facilities as it is critical to our long-term success. We also evaluate appropriate investment levels and stay focused on new product introductions to improve our competitiveness. We expect that our research and development expenses will fluctuate from time to time.

Selling, general and administrative expenses.  Our selling, general and administrative expenses consist primarily of salaries, bonuses, benefits, share-based compensation expense, product promotion costs, occupancy costs, travel expenses, expenses related to sales and marketing activities, amortization of software, depreciation of equipment, maintenance costs and

other expenses for general and administrative functions as well as costs for outside professional services, including legal, audit and accounting services. We expect our selling, general and administrative expenses to fluctuate in the near future as we continue to exercise cost control measures.

Impairment of Long-Lived Assets: Long-lived assets or asset groups are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset might not be recoverable. The recoverability of an asset or asset group is assessed by determining if the carrying value of the asset or asset group exceeds the sum of the projected undiscounted cash flows expected to result from the use and eventual disposition of the assets over the remaining economic life.  The impairment loss is measured based on the difference between the carrying amount and estimated fair value.

Income tax expense

We are subject to income taxes in various jurisdictions. Significant judgment and estimates are required in determining our worldwide income tax expense. The calculation of tax liabilities involves dealing with uncertainties in the application of complex tax regulations of different jurisdictions globally. We establish accruals for potential liabilities and contingencies based on a more likely than not threshold to the recognition and de-recognition of uncertain tax positions. If the recognition threshold is met, the applicable accounting guidance permits us to recognize a tax benefit measured at the largest amount of tax benefit that is more likely than not to be realized upon settlement with a taxing authority. If the actual tax outcome of such exposures is different from the amounts that were initially recorded, the differences will impact the income tax and deferred tax provisions in the period in which such determination is made. Changes in the location of taxable income (loss) could result in significant changes in our income tax expense.

We record a valuation allowance against deferred tax assets if it is more likely than not that a portion of the deferred tax assets will not be realized, based on historical profitability and our estimate of future taxable income in a particular jurisdiction. Our judgments regarding future taxable income may change due to changes in market conditions, changes in tax laws, tax planning strategies or other factors. If our assumptions and consequently our estimates change in the future, the deferred tax assets may increase or decrease, resulting in corresponding changes in income tax expense. Our effective tax rate is highly dependent upon the geographic distribution of our worldwide profits or losses, the tax laws and regulations in each geographical region where we have operations, the availability of tax credits and carry-forwards and the effectiveness of our tax planning strategies.

During the quarter ended September 30, 2016, we contributed certain packaging equipment as required by the JV Agreement by transferring the legal title of such equipment to the JV Company. As a result of the transfer, we reduced our deferred tax assets by $6.6 million and recorded a $6.6 million as a prepaid tax asset, which was amortized to tax expense over the useful life of the assets. As of June 30, 2017, the prepaid tax asset was amortized down to $5.5 million, of which $1.1 million and $4.4 million were included in prepaid and other current assets and in other long-term assets on our balance sheet, respectively. On July 1, 2017, we adopted ASU 2016-16, Intra-Entity Transfers of Assets other than Inventory, which resulted in a de-recognition of a prepaid tax asset of $5.5 million related to the prior period intra-entity asset transfer with the JV Company, with an offsetting reduction to retained earnings.  Because the JV Company has a full valuation allowance, there was no change to our net deferred tax assets.

U.S. Tax Cuts and Jobs Act, Enacted December 22, 2017

On December 22, 2017, the United States enacted tax reform legislation through the Tax Cuts and Jobs Act ("the Tax Act"), which significantly changes the existing U.S. tax laws, including, but not limited to, (1) a reduction in the corporate tax rate from 35% to 21%, (2) a move from a worldwide tax system to a territorial system, (3) eliminating the corporate alternative minimum tax (AMT) and changing how existing AMT credits can be realized, (4) bonus depreciation that will allow for full expensing of qualified property, (5) creating a new limitation on deductible interest expense and (6) changing rules related to uses and limitations of net operating loss carryforwards created in tax years beginning after December 31, 2017.

The SEC staff issued Staff Accounting Bulletin No. 118 ("SAB 118"), which provides guidance on accounting for the tax effects of the Tax Act. SAB 118 provides a measurement period that should not extend beyond one year from the Tax Act enactment date for companies to complete the accounting under Accounting Standards Codification Topic 740 ("ASC 740"). In accordance with SAB 118, a company must reflect the income tax effects of those aspects of the Tax Act for which the accounting under ASC 740 is complete. To the extent that a company's accounting for certain income tax effects of the Tax Act is incomplete but it is able to determine a reasonable estimate, it must record a provisional estimate in the financial statements. If a company cannot determine a provisional estimate to be included in the financial statements, it should continue to apply ASC 740 on the basis of the provisions of the tax law that were in effect immediately before the enactment of the Tax Act.

In connection with our initial analysis of the impact of the Tax Act, we reported a second quarter of fiscal year 2018 discrete tax benefit of $2.7 million related to the re-measurement of certain deferred tax assets and liabilities. The $2.7 million tax benefit related to the tax rate re-measurement estimated in the second quarter of fiscal year 2018 was reduced downward by $0.2 million in the fourth quarter of fiscal year 2018, to $2.5 million. In addition, we are using a 28% U.S. federal tax rate to measure our U.S. federal income tax expense for fiscal year 2018, down from the 34% U.S. federal income tax rate used in first quarter of fiscal year 2018.

Our accounting for the impact of the Tax Act is complete for provisions of the Act that could impact our fiscal year 2018 financial statements.  We are still analyzing the provisions of the Act that may impact future periods.  Our management expects the Act to favorably impact our net income, diluted earnings per share, and cash flows in future periods, due primarily to the reduction in the federal corporate tax rate from 35% to 21% effective for periods beginning January 1, 2018.

Operating results

The following tables set forth our results of operations and as a percentage of revenue for the fiscal years ended June 30, 2018 , 2017 and 2016 . Our historical results of operations are not necessarily indicative of the results for any future period.

(1) Includes share-based compensation expense as follows:

Revenue

The following is a summary of revenue by product type:

Fiscal 2018 vs 2017

Total revenue was $421.6 million for fiscal year 2018 , an increase of $38.2 million , or 10.0% , as compared to $383.3 million for fiscal year 2017 . The increase was primarily due to an increase of $53.4 million in sales of power discrete products, partially offset by a decrease of $15.3 million in sales of power IC products. The net increase in product sales was primarily due to a 2.1% increase in unit shipments, as well as an 8.1% increase in average selling price as compared to last fiscal year due to a shift in product mix. The increase in revenue of packaging and testing services for fiscal year 2018 as compared to last fiscal year was primarily due to increased demand. During fiscal year 2018, we accelerated the development of new technology platforms which allowed us to introduce 43 medium and high voltage MOSFET products, targeting primarily the industrial markets, as well as 37 low voltage MOSFET products primarily for the computing and communication markets. In addition, we introduced 66 Power IC new products for consumer, computing applications and communication markets.

Fiscal 2017 vs 2016

Total revenue was $383.3 million for fiscal year 2017, an increase of $47.7 million, or 14.2%, as compared to $335.7 million for fiscal year 2016. The increase consisted of $36.7 million and $13.0 million in sales of power discrete products and sales of power IC products, respectively, partially offset by a $2.1 million decrease in sales of packaging and testing services. The increase in power discrete and power IC products was primarily due to a 17.5% increase in unit shipments, partially offset by a 1.9% decrease in average selling price as compared to last fiscal year due to a shift in product mix. The decrease in revenue of packaging and testing services as compared to last year was primarily due to reduced demand.

Cost of goods sold and gross profit

Fiscal 2018 vs 2017

Cost of goods sold was $309.6 million for fiscal year 2018 , an increase of $18.1 million , or 6.2% , as compared to $291.5 million for fiscal year 2017 . The increase was primarily due to increased unit shipments. Gross margin increased by 2.6 percentage points to 26.6% for fiscal year 2018 , as compared to 24.0% for fiscal year 2017 . The increase in gross margin was primarily due to a shift in product mix and higher factory utilization, as well as approximately $2.0 million of specific reserve that was release during the fiscal year 2018. We expect our gross margin to continue to fluctuate in the future as a result of variations in our product mix, factory utilization, semiconductor wafer and raw material pricing, manufacturing labor cost and general economic and PC market conditions.

Fiscal 2017 vs 2016

Cost of goods sold was $291.5 million for fiscal year 2017, an increase of $21.7 million, or 8.0%, as compared to $269.8 million for fiscal year 2016. The increase was primarily due to increased unit shipments. The increase was partially offset by the overall manufacturing cost reduction due to improved factory utilization as compared to last fiscal year. Gross margin increased by 4.4 percentage points to 24.0% for fiscal year 2017, as compared to 19.6% for fiscal year 2016. The increase in gross margin was primarily due to better product mix and higher factory utilization, partially offset by lower average selling prices.

Research and development expenses

Fiscal 2018 vs 2017

Research and development expenses were $37.3 million for fiscal year 2018 , an increase of $7.5 million , or 25.2% , as compared to $29.8 million for fiscal year 2017 . The increase was primarily attributable to a $3.0 million increase in employee compensation and benefit expenses mainly due to higher bonus expenses and increased headcount to ramp up our digital power business, a $2.7 million increase in product prototyping engineering expenses as a result of increased engineering activities, a $0.5 million increase in share-based compensation expense as a result of an increase of stock awards granted, a $0.5 million increase in consulting expenses due to more consulting activities, and a $0.3 million increase in depreciation expenses. We continue to evaluate and invest resources in developing new technologies and products utilizing our own fabrication and packaging facilities. We expect that our research and development expenses will fluctuate from time to time.

Fiscal 2017 vs 2016

Research and development expenses were $29.8 million for fiscal year 2017, an increase of $3.8 million, or 14.7%, as compared to $26.0 million for fiscal year 2016. The increase was primarily attributable to a $2.6 million increase in employee compensation and benefit expenses mainly due to increased headcount and higher bonus expenses, a $1.0 million increase in product prototyping engineering expenses as a result of increased engineering activities, and a $0.2 million increase in share-based compensation expense as a result of an increase of stock awards granted.

Selling, general and administrative expenses

Fiscal 2018 vs 2017

Selling, general and administrative expenses were $66.2 million for fiscal year 2018 , an increase of $17.3 million , or 35.5% , as compared to $48.8 million for fiscal year 2017 . The increase was primarily due to a $12.3 million increase in employee compensation and benefits expense as a result of pre-production costs in the JV Company, increased headcount and higher bonus expenses, a $3.7 million increase in share-based compensation expense due to increased grant of equity awards, and a $1.0 million increase in employee business expenses due to increased travel expenses during the current fiscal year.

Fiscal 2017 vs 2016

Selling, general and administrative expenses were $48.8 million for fiscal year 2017, an increase of $11.0 million, or 29.0%, as compared to $37.9 million for fiscal year 2016. The increase was primarily due to a $6.6 million increase in

employee compensation and benefits expense as a result of increased headcount and higher bonus expenses, a $1.7 million increase in share-based compensation expense as a result of an increase of stock awards granted and a decrease in the cancellation of numbers of shares, a $1.0 million increase in consulting fees primarily due to increased professional services costs and recruiting costs, a $0.3 million increase in audit and tax consulting fees due to increased consulting activities, as well as a $0.6 million in employee business expenses due to increased travel expenses.

Impairment of long-lived assets

During the quarter ended December 31, 2015, we identified certain manufacturing equipment purchased for projects that were subsequently canceled. Because the equipment had no alternative uses, we recorded an asset impairment expense of approximately $0.4 million related to these equipment during the quarter ended December 31, 2015.

Interest income and other income (loss), net

Interest income and other, net was primarily related to interest earned from cash and cash equivalents, as well as foreign exchange gains (losses). The decrease in interest income and others, net in fiscal year 2018 as compared to fiscal year 2017 was primarily due to a $2.1 million increase in foreign exchange losses as a result of recent depreciation of USD, partially offset by a $0.3 million increase in interest income as a result of an increase in average cash balances. The increase in interest income and others, net in fiscal year 2017 as compared to fiscal year 2016 was primarily due to increase in average cash balances, as well as lower foreign exchange losses as a result of appreciation of USD against RMB.

Interest Expense

Interest expense was primarily related to bank borrowings. The increase in interest expenses for fiscal year 2018 was primarily due to an increase in bank borrowings, including the $13.2 million of term loan drew down in January 2018 for the purpose of purchasing certain equipment for our Oregon fab, $17.8 million term loan obtained in May 2018 and approximately $60.4 million (400 million RMB) financing lease in May 2018 for the acquisition and installation of the 12" fabrication equipment and other expenses of the JV Company relating to the completion of the fabrication facility located in Chongqing. The interest expense in fiscal year 2017 remained flat as the fiscal year 2016.

Income tax expense

Fiscal 2018 vs 2017

Income tax expense for fiscal years 2018 and 2017 was $0.7 million and $3.7 million , respectively. Income tax expense decreased by $2.9 million , or 80.6% , in fiscal year 2018 as compared to fiscal year 2017 primarily due to a $2.5 million tax benefit from re-measuring our U.S. deferred tax liabilities following the enactment of the 2017 U.S. Tax Cuts and Jobs Act in December 2017. Additional tax savings were generated in fiscal year 2018 due to changes in the mix of earnings in various geographic jurisdictions between the respective periods and a lower U.S. tax rate in fiscal year 2018. Excluding the discrete income tax items, the effective tax rate for the current fiscal year was 61.7%, compared to 36.6% for the last fiscal year. The changes in the effective tax rate and tax expense between the fiscal years resulted primarily from changes in the mix of earnings in various geographic jurisdictions between the current year and prior year, partially offset by the reduction in the U.S. corporate tax rate following the enactment of the 2017 U.S. Tax Cut and Jobs Act.

Fiscal 2017 vs 2016

Income tax expense for fiscal years 2017 and 2016 was $3.7 million and $4.0 million, respectively. Income tax expense decreased by $0.4 million, or 9.2% in fiscal year 2017 as compared to fiscal year 2016 primarily due to a reduction in our uncertain positions, partially offset by changes in the mix of earnings in various geographic jurisdictions between the respective periods.

Liquidity and Capital Resources

Our principal need for liquidity and capital resources is to maintain sufficient working capital to support our operations and to invest adequate capital expenditures to fuel the growth of our business. To date, we finance our operations and capital expenditures primarily through funds generated from operations and borrowings under our term loans and financing lease.

On May 9, 2018 (the "Effective Date"), the JV Company entered into a lease finance agreement and a security agreement (the "Agreements") with YinHai Leasing Company and China Import/Export Bank (the "Lenders").  Pursuant to the Agreements, the Lenders agree to provide an aggregate of Chinese Renminbi (RMB) 400.0 million, or $62.8 million based on the currency exchange rate between RMB and U.S. Dollars on the Effective Date, of financing to the JV Company (the "Lease Financing"). In exchange for the Lease Financing, the JV Company agrees to transfer title of its assembly and testing equipment to the Lenders, and the Lenders lease such equipment to the JV Company under a five-year lease arrangement, pursuant to which the JV Company makes quarterly lease payments to the Lenders consisting of principal and interest based on a repayment schedule mutually agreed by the parties.  The interest under the Lease Financing is accrued based on the China Base Rate multiplied by 1.15, or 5.4625% on the Effective Date.  Under the Agreements, at the end of the five-year lease term, the Lenders agree to sell such equipment back to the JV Company for a nominal amount (RMB 1).  The JV Company's obligations under the Lease Financing are secured by the land and building owned by the JV Company (the "Collateral").  The proceeds from the Lease Financing will be used primarily for the acquisition and installation of the 12" fabrication equipment and other expenses of the JV Company relating to the completion of the fabrication facility located in Chongqing. The Agreements contain customary representation, warranties and covenants, including restrictions on the transfer of the Collateral. The Agreements also contain customary events of default, including but are not limited to, failure to make payments and breach of material terms under the Agreements. The Agreements include certain customary closing conditions, including the payment of deposit by the JV Company. We are in compliance with these covenants. As of June 30, 2018, the outstanding balance of the Lease Financing was 400 million RMB (equivalent of $60.4 million based on the currency exchange rate as of June 30, 2018). In addition, pursuant to the terms of the Agreement, we made an additional $25.0 million of cash contribution to the JV company, which resulted in the Company owning 54%, and the Chongqing Funds owning 46%, of the equity interest in the JV Company.

On May 1, 2018, our Oregon subsidiary, Jireh Semiconductor Incorporated ("Jireh") entered into a loan agreement with the Bank that provided a term loan in an amount of $17.8 million. The obligation under the loan agreement is secured by certain real estate assets of Jireh and guaranteed by the Company, including AOS US.  The loan has a five-year term and matures on June 1, 2023. Beginning June 1, 2018, Jireh shall make consecutive monthly payments of principal and interest to the Bank. The outstanding principal shall accrue interest at a fixed rate of 5.042% per annum on the basis of a 360-day year.

The loan agreement contains customary restrictive covenants and includes certain financial covenants that require us to maintain, on a consolidated basis, specified financial ratios. We are in compliance with these covenants. As of June 30, 2018, the outstanding balance of the term loan was $17.7 million.

On August 15, 2017, Jireh entered into a credit agreement with a financial institution (the "Bank") that provided a term loan in an amount up to $30.0 million for the purpose of purchasing certain equipment for our fabrication facility located in Oregon. The obligation under the credit agreement is secured by substantially all of the assets of Jireh and guaranteed by the Company, including our subsidiary, Alpha and Omega Semiconductor Incorporated ("AOS US"). The credit agreement has a five-year term and matures on August 15, 2022. In January 2018 and July 2018, Jireh drew down on the loan in the amount of $13.2 million and $16.7 million, respectively. Beginning September 2018, Jireh is required to pay to the Bank on each payment date, the outstanding principal amount of the loan in monthly installments. The monthly loan interest is based on an adjusted London Interbank Offered Rate ("LIBOR") as defined in the credit agreement, plus specified applicable margin in the range of 1.75% to 2.25%, based on the outstanding balance of the loan. The credit agreement contains customary restrictive covenants and includes certain financial covenants that require the Company to maintain, on a consolidated basis, specified financial ratios and fixed charge coverage ratio. We are in compliance with these covenants. As of June 30, 2018 , the outstanding balance of the term loan was $13.2 million.

In March 2016, we entered into the JV Agreement with an initial capitalization of $330.0 million. As of June 30, 2018 , the Chongqing Funds contributed a total of $162.0 million of initial capital in cash, and we contributed $10.0 million in cash and certain intangible assets, as well as certain packaging equipment as required by the JV Agreement by transferring the legal titles of such equipment to the JV Company. The JV Company substantially completed its assembly and testing and 12-inch wafer fab facilities during the quarter ended June 30, 2018. We expect to commence limited mass production for assembly and testing in the second half of calendar year 2018, and trial production of the 12-inch wafer fabrication facility toward the end of calendar year 2018. Over the long-term, the JV Company plans to construct and operate a 12-inch wafer fabrication facility for the manufacturing or semiconductor products. If both parties agree that the termination of the JV Company is the best interest of each party or the JV Company is bankrupt or insolvent where either party may terminate early, after paying the debts of the JV Company, the remaining assets of the JV Company shall be paid to the Chongqing Funds to cover the principal of its total paid-in contributions plus the interest at 10% simple annual rate prior to distributing the balance of the JV Company's assets to us.

In January 2017, the JV Company entered into the EPC Contract. The total price payable by the JV Company under the EPC Contract is RMB 540.0 million, or approximately $78.0 million based on the currency exchange rate between RMB and U.S. Dollars on the Effective Date, which consists of $2.8 million (RMB 19.5 million) of design fees and $75.2 million (RMB 520.5 million) of construction and procurement fees. These fees will be paid by the JV Company pursuant to a payment schedule based on the progress of the construction and the achievements of specified milestones. The payment is subject to volatility as a result of exposure to fluctuations in RMB foreign exchange rates. The Design Fees and Construction Fees are paid by the JV Company pursuant to a payment schedule based on the progress of the construction and the achievements of specified milestones. As of June 30, 2018 , the JV Company paid approximately $66.4 million (RMB 439.5 million ), and expect to pay the remaining of $15.2 million (RMB 100.5 million ) in fiscal year 2019.

In September 2017, the Board of Directors terminated our prior repurchase program that was approved in 2015 and approved a new repurchase program (the "Repurchase Program"). The Repurchase Program allows us to repurchase our common shares from the open market pursuant to a pre-established Rule 10b5-1 trading plan or through privately negotiated transactions up to an aggregate of $30.0 million. The amount and timing of any repurchases under the Repurchase Program depend on a number of factors, including but not limited to, the trading price, volume and availability of our common shares. Shares repurchased under this program are accounted for as treasury shares and the total cost of shares repurchased is recorded as a reduction of shareholders' equity. There is no guarantee that such repurchases under the Purchase Program will enhance the value of our shares. Since the inception of the program in 2010, we repurchased an aggregate of 6,673,139 shares from the open market under the Repurchase Trading Plan for a total cost of $65.8 million, at an average price of $9.87 per share, excluding fees and related expenses of $0.4 million. No repurchased shares have been retired. Shares repurchased are accounted for as treasury shares and the total cost of shares repurchased is recorded as a reduction of shareholders' equity. During fiscal years 2018 and 2017, the Company repurchased an aggregate of 950,046 shares and 0 shares, respectively. As of June 30, 2018 , of the 6,673,139 repurchased shares, 132,728 shares with a weighted average repurchase price of $10.50 per share, were reissued at an average price of $5.81 per share for option exercises and vested restricted share units. We had $14.9 million available under our repurchase program as of June 30, 2018 .    

On September 5, 2017, we entered into a license agreement with STMicroelectronics International N.V. ("STMicro"), pursuant to which STMicro granted us a world-wide, royalty-free and fully-paid license to use its technologies to develop, market and distribute certain digital multi-phase controller products, which have been offered by STMicro.  Under the license

agreement, we agreed to pay a total price in cash of $17.0 million based on the payment schedule as set forth in the agreement of approximately $10.1 million, $6.7 million and $0.2 million in calendar year 2017, 2018 and 2019, respectively. As of June 30, 2018, we recorded $15.8 million of intangible assets related to STMicro.

The Chinese government imposes certain currency exchange controls on cash transfers out of China. Regulations in China permit foreign owned entities to freely convert the Renminbi into foreign currency for transactions that fall under the "current account," which includes trade related receipts and payments, interests, and dividend payments. Accordingly, subject to the review and verification of the underlying transaction documents and supporting documents by the account banks in China, our Chinese subsidiaries may use Renminbi to purchase foreign exchange currency for settlement of such "current account" transactions without the pre-approval from China's State Administration of Foreign Exchange (SAFE) or its provincial branch. Pursuant to applicable regulations, foreign-invested enterprises in China may pay dividends only out of their accumulated profits, if any, determined in accordance with Chinese accounting standards and regulations. In calculating accumulated profits, foreign-invested enterprises in China are required to allocate at least 10% of their profits each year, if any, to fund the equity reserve account unless the reserve has reached 50% of the registered capital of the enterprises. While SAFE approval is not statutorily required for eligible dividend payments to the foreign parent, in practice, before making the dividend payment, the account bank may seek SAFE's opinion with respect to a dividend payment if the payment involves a relatively large amount, which may delay the dividend payment depending on the then overall status of cross-border payments and receipts of China.

Transactions that involve conversion of Renminbi into foreign currency in relation to foreign direct investments and provision of debt financings in China are classified as "capital account" transactions. Examples of "capital account" transactions include repatriations of investments by foreign owners and repayments of loan principal to foreign lenders. "Capital account" transactions require prior approval from SAFE or its provincial branch or an account bank delegated by SAFE to convert a remittance into a foreign currency, such as U.S. dollars, and transmit the foreign currency outside of China. As a result of this and other restrictions under PRC laws and regulations, our China subsidiaries are restricted in their ability to transfer a portion of their net assets to the parent, and such restriction may adversely affect our ability to generate sufficient liquidity to fund our operations or other expenditures. As of June 30, 2018 and 2017 , such restricted portion amounted to approximately $279.6 million and $140.1 million, or 65.6% and 51.7% , of our total consolidated net assets, respectively. The increase of restricted net assets was primarily from the JV Company in China.

We believe that our current cash and cash equivalents and cash flows from operations will be sufficient to meet our anticipated cash needs, including working capital and capital expenditures, for at least the next twelve months. In the long-term, we may require additional capital due to changing business conditions or other future developments, including any investments or acquisitions we may decide to pursue. If our cash is insufficient to meet our needs, we may seek to raise capital through equity. The sale of additional equity securities could result in dilution to our shareholders.

Cash and cash equivalents

As of June 30, 2018 and 2017 , we had $131.5 million and $115.7 million of cash and cash equivalents, respectively. Our cash and cash equivalents primarily consist of cash on hand and short-term bank deposits with original maturities of three months or less. Of the $131.5 million and $115.7 million cash and cash equivalents, $100.9 million and $73.9 million, respectively, are deposited with financial institutions outside the United States.

The following table shows our cash flows from operating, investing and financing activities for the periods indicated: