POWER INTEGRATIONS INC 10-K

Item 8. Financial Statements and Supplementary Data. REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM To the Stockholders and the Board of Directors of Power Integrations, Inc. Opinion on the Financial Statements We have audited the accompanying consolidated balance sheets of Power Integrations, Inc. and subsidiaries (the "Company") as of December 31, 2020 and 2019, the related consolidated statements of income, comprehensive income, stockholders' equity, and cash flows for each of the three years in the period ended December 31, 2020, and the related notes (collectively referred to as the "financial statements"). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2020 and 2019, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2020, in conformity with the accounting principles generally accepted in the United States of America. We have also audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the Company's internal control over financial reporting as of December 31, 2020, based on criteria established in Internal Control - Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission and our report dated February 5, 2021 expressed an unqualified opinion on the Company's internal control over financial reporting. Change in Accounting Principle As discussed in Note 12 to the financial statements, effective January 1, 2019, the Company adopted Accounting Standards Update (ASU) 2016-02, Leases (Topic 842), using the optional transition method. Basis for Opinion These financial statements are the responsibility of the Company's management. Our responsibility is to express an opinion on the Company's financial statements based on our audits. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB. We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion. Critical Audit Matters Critical audit matters are matters arising from the current-period audit of the financial statements that were communicated or required to be communicated to the audit committee and that (1) relate to accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, subjective, or complex judgments. We determined that there are no critical audit matters. ​ /s/ DELOITTE & TOUCHE LLP San Jose, California February 5, 2021 We have served as the Company’s auditor since 2005. ​ 34 Table of Contents POWER INTEGRATIONS, INC. CONSOLIDATED BALANCE SHEETS ​ ​ ​ ​ ​ ​ ​ ​ December 31, December 31, (In thousands, except par value) ​ 2020 ​ 2019 ASSETS ​ ​ CURRENT ASSETS: ​ ​ Cash and cash equivalents ​ $ 258,874 ​ $ 178,690 Short-term marketable securities ​ 190,318 ​ 232,398 Accounts receivable, net ​ 35,910 ​ 24,274 Inventories ​ 102,878 ​ 90,380 Prepaid expenses and other current assets ​ 13,252 ​ 15,597 Total current assets ​ 601,232 ​ 541,339 PROPERTY AND EQUIPMENT, net ​ 166,188 ​ 116,619 INTANGIBLE ASSETS, net ​ 12,506 ​ 16,865 GOODWILL ​ 91,849 ​ 91,849 DEFERRED TAX ASSETS ​ 3,339 ​ 2,836 OTHER ASSETS ​ 28,225 ​ 34,388 Total assets ​ $ 903,339 ​ $ 803,896 LIABILITIES AND STOCKHOLDERS’ EQUITY ​ ​ CURRENT LIABILITIES: ​ ​ Accounts payable ​ $ 34,712 ​ $ 27,433 Accrued payroll and related expenses ​ 14,806 ​ 13,408 Taxes payable ​ 902 ​ 584 Other accrued liabilities ​ 12,106 ​ 9,051 Total current liabilities ​ 62,526 ​ 50,476 LONG-TERM INCOME TAXES PAYABLE ​ 15,588 ​ 14,617 DEFERRED TAX LIABILITIES ​ 75 ​ 164 OTHER LIABILITIES ​ 14,739 ​ 14,093 Total liabilities ​ 92,928 ​ 79,350 COMMITMENTS AND CONTINGENCIES (Notes 11, 12 and 13) ​ ​ STOCKHOLDERS’ EQUITY: ​ ​ Common stock, $ 0.001 par value ​ ​ Authorized - 280,000 shares ​ ​ Outstanding - 59,910 and 58,862 shares in 2020 and 2019, respectively ​ 28 ​ 28 Additional paid-in capital ​ 190,920 ​ 152,117 Accumulated other comprehensive loss ​ ( 2,163 ) ​ ( 3,130 ) Retained earnings ​ 621,626 ​ 575,531 Total stockholders’ equity ​ 810,411 ​ 724,546 Total liabilities and stockholders’ equity ​ $ 903,339 ​ $ 803,896 ​ The accompanying notes are an integral part of these consolidated financial statements. ​ 35 Table of Contents POWER INTEGRATIONS, INC. CONSOLIDATED STATEMENTS OF INCOME ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, (In thousands, except per share amounts) ​ 2020 2019 2018 NET REVENUES ​ $ 488,318 ​ $ 420,669 ​ $ 415,955 COST OF REVENUES ​ 244,728 ​ 207,267 ​ 201,167 GROSS PROFIT ​ 243,590 ​ 213,402 ​ 214,788 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ OPERATING EXPENSES: ​ ​ ​ Research and development ​ 81,711 ​ 73,470 ​ 70,580 Sales and marketing ​ 54,497 ​ 54,297 ​ 53,064 General and administrative ​ 36,895 ​ 37,582 ​ 35,496 Litigation settlement ​ — ​ ( 168,969 ) ​ — Total operating expenses ​ 173,103 ​ ( 3,620 ) ​ 159,140 INCOME FROM OPERATIONS ​ 70,487 ​ 217,022 ​ 55,648 OTHER INCOME ​ 4,764 ​ 5,392 ​ 4,116 INCOME BEFORE INCOME TAXES ​ 75,251 ​ 222,414 ​ 59,764 PROVISION (BENEFIT) FOR INCOME TAXES ​ 4,075 ​ 28,946 ​ ( 10,220 ) NET INCOME ​ $ 71,176 ​ $ 193,468 ​ $ 69,984 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ EARNINGS PER SHARE: ​ ​ ​ Basic ​ $ 1.19 ​ $ 3.31 ​ $ 1.19 Diluted ​ $ 1.17 ​ $ 3.24 ​ $ 1.16 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ SHARES USED IN PER SHARE CALCULATION: ​ ​ ​ Basic ​ 59,657 ​ 58,534 ​ 58,912 Diluted ​ 60,845 ​ 59,632 ​ 60,294 ​ The accompanying notes are an integral part of these consolidated financial statements. The Earnings Per Share and Shares Used in Per Share Calculation information presented above reflects the effect of the August 2020 stock split. Refer to Note 10, Earnings Per Share , in this Form 10-K for details . ​ 36 Table of Contents POWER INTEGRATIONS, INC. CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, (In thousands) 2020 2019 2018 Net income ​ $ 71,176 ​ $ 193,468 ​ $ 69,984 Other comprehensive income (loss), net of tax: ​ ​ ​ Foreign currency translation adjustments, net of $ 0 tax in 2020, 2019 and 2018 ​ ( 183 ) ​ ( 518 ) ​ ( 236 ) Unrealized gain on marketable securities, net of $ 0 tax in 2020, 2019 and 2018 ​ 307 ​ 849 ​ 161 Unrealized actuarial gain (loss) on pension benefits, net of tax of ($ 308 ), $ 497 , and ($ 144 ) in 2020, 2019 and 2018, respectively ​ 843 ​ ( 1,772 ) ​ 525 Total other comprehensive income (loss) ​ 967 ​ ( 1,441 ) ​ 450 TOTAL COMPREHENSIVE INCOME ​ $ 72,143 ​ $ 192,027 ​ $ 70,434 ​ The accompanying notes are an integral part of these consolidated financial statements. ​ 37 Table of Contents POWER INTEGRATIONS, INC. CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accumulated ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Additional ​ Other ​ ​ ​ ​ Total ​ ​ Common Stock ​ Paid-In ​ Comprehensive ​ Retained ​ Stockholders’ (In thousands) Shares Amount Capital Loss Earnings Equity BALANCE AT JANUARY 1, 2018 59,564 ​ $ 29 ​ $ 198,384 ​ $ ( 2,139 ) ​ $ 351,408 ​ $ 547,682 Issuance of common stock under employee stock option and stock award plans 1,182 ​ — ​ 4,010 ​ — ​ — ​ 4,010 Repurchase of common stock ( 3,144 ) ​ ( 1 ) ​ ( 103,153 ) ​ — ​ — ​ ( 103,154 ) Issuance of common stock under employee stock purchase plan 176 ​ — ​ 5,343 ​ — ​ — ​ 5,343 Stock-based compensation expense related to employee stock options and awards — ​ — ​ 20,027 ​ — ​ — ​ 20,027 Stock-based compensation expense related to employee stock purchases — ​ — ​ 1,553 ​ — ​ — ​ 1,553 Payment of dividends to stockholders — ​ — ​ — ​ — ​ ( 18,823 ) ​ ( 18,823 ) Unrealized actuarial gain on pension benefits — ​ — ​ — ​ 525 ​ — ​ 525 Unrealized gain on marketable securities — ​ — ​ — ​ 161 ​ — ​ 161 Foreign currency translation adjustment — ​ — ​ — ​ ( 236 ) ​ — ​ ( 236 ) Net income — ​ — ​ — ​ — ​ 69,984 ​ 69,984 BALANCE AT DECEMBER 31, 2018 57,778 ​ 28 ​ 126,164 ​ ( 1,689 ) ​ 402,569 ​ 527,072 Issuance of common stock under employee stock option and stock award plans 1,130 ​ — ​ 4,359 ​ — ​ — ​ 4,359 Repurchase of common stock ( 242 ) ​ — ​ ( 7,302 ) ​ — ​ — ​ ( 7,302 ) Issuance of common stock under employee stock purchase plan 196 ​ — ​ 5,549 ​ — ​ — ​ 5,549 Stock-based compensation expense related to employee stock awards — ​ — ​ 21,686 ​ — ​ — ​ 21,686 Stock-based compensation expense related to employee stock purchases — ​ — ​ 1,661 ​ — ​ — ​ 1,661 Payment of dividends to stockholders — ​ — ​ — ​ — ​ ( 20,506 ) ​ ( 20,506 ) Unrealized actuarial loss on pension benefits — ​ — ​ — ​ ( 1,772 ) ​ — ​ ( 1,772 ) Unrealized gain on marketable securities — ​ — ​ — ​ 849 ​ — ​ 849 Foreign currency translation adjustment — ​ — ​ — ​ ( 518 ) ​ — ​ ( 518 ) Net income — ​ — ​ — ​ — ​ 193,468 ​ 193,468 BALANCE AT DECEMBER 31, 2019 58,862 ​ 28 ​ 152,117 ​ ( 3,130 ) ​ 575,531 ​ 724,546 Issuance of common stock under employee stock option and stock award plans 963 ​ — ​ 4,608 ​ — ​ — ​ 4,608 Repurchase of common stock ( 63 ) ​ — ​ ( 2,636 ) ​ — ​ — ​ ( 2,636 ) Issuance of common stock under employee stock purchase plan 148 ​ — ​ 5,919 ​ — ​ — ​ 5,919 Stock-based compensation expense related to employee stock awards — ​ — ​ 28,952 ​ — ​ — ​ 28,952 Stock-based compensation expense related to employee stock purchases — ​ — ​ 1,960 ​ — ​ — ​ 1,960 Payment of dividends to stockholders — ​ — ​ — ​ — ​ ( 25,081 ) ​ ( 25,081 ) Unrealized actuarial gain on pension benefits — ​ — ​ — ​ 843 ​ — ​ 843 Unrealized gain on marketable securities — ​ — ​ — ​ 307 ​ — ​ 307 Foreign currency translation adjustment — ​ — ​ — ​ ( 183 ) ​ — ​ ( 183 ) Net income — ​ — ​ — ​ — ​ 71,176 ​ 71,176 BALANCE AT DECEMBER 31, 2020 59,910 ​ $ 28 ​ $ 190,920 ​ $ ( 2,163 ) ​ $ 621,626 ​ $ 810,411 ​ The accompanying notes are an integral part of these consolidated financial statements. The Shares presented above reflects the effect of the August 2020 stock split. Refer to Note 10, Earnings Per Share , in this Form 10-K for details . ​ 38 Table of Contents POWER INTEGRATIONS, INC. CONSOLIDATED STATEMENTS OF CASH FLOWS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, (In thousands) 2020 2019 2018 CASH FLOWS FROM OPERATING ACTIVITIES: ​ ​ ​ Net income ​ $ 71,176 ​ $ 193,468 ​ $ 69,984 Adjustments to reconcile net income to net cash provided by operating activities: ​ ​ ​ Depreciation ​ 23,743 ​ 19,190 ​ 18,918 Amortization of intangibles ​ 4,359 ​ 5,213 ​ 5,267 Loss on disposal of property and equipment ​ 525 ​ 249 ​ 553 Stock-based compensation expense ​ 30,912 ​ 23,347 ​ 21,580 Amortization of premium (accretion of discount) on marketable securities ​ 705 ​ ( 192 ) ​ 227 Deferred income taxes ​ ( 592 ) ​ 4,019 ​ ( 4,465 ) Increase (decrease) in accounts receivable allowance for credit losses, net ​ ( 336 ) ​ 57 ​ ( 28 ) Change in operating assets and liabilities: ​ ​ ​ Accounts receivable ​ ( 11,300 ) ​ ( 13,259 ) ​ 5,754 Inventories ​ ( 12,498 ) ​ ( 9,523 ) ​ ( 23,770 ) Prepaid expenses and other assets ​ 9,153 ​ ( 2,132 ) ​ ( 1,495 ) Accounts payable ​ 5,697 ​ ( 6,556 ) ​ 1,336 Taxes payable and accrued liabilities ​ 4,095 ​ 10,618 ​ ( 9,897 ) Net cash provided by operating activities ​ 125,639 ​ 224,499 ​ 83,964 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ CASH FLOWS FROM INVESTING ACTIVITIES: ​ ​ ​ Purchases of property and equipment ​ ( 70,598 ) ​ ( 24,114 ) ​ ( 24,677 ) Proceeds from sale of property and equipment ​ ​ 651 ​ ​ — ​ ​ — Acquisition of technology licenses ​ — ​ ( 1,026 ) ​ ( 900 ) Purchases of marketable securities ​ ( 109,703 ) ​ ( 207,240 ) ​ ( 62,833 ) Proceeds from sales and maturities of marketable securities ​ 151,385 ​ 70,334 ​ 157,551 Net cash provided by (used in) investing activities ​ ( 28,265 ) ​ ( 162,046 ) ​ 69,141 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ CASH FLOWS FROM FINANCING ACTIVITIES: ​ ​ ​ Issuance of common stock under employee stock plans ​ 10,527 ​ 9,908 ​ 9,353 Repurchase of common stock ​ ( 2,636 ) ​ ( 7,302 ) ​ ( 103,153 ) Payments of dividends to stockholders ​ ( 25,081 ) ​ ( 20,506 ) ​ ( 18,823 ) Proceeds from draw on line of credit ​ — ​ — ​ 8,000 Payments on line of credit ​ — ​ — ​ ( 8,000 ) Net cash used in financing activities ​ ( 17,190 ) ​ ( 17,900 ) ​ ( 112,623 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ NET INCREASE IN CASH AND CASH EQUIVALENTS ​ 80,184 ​ 44,553 ​ 40,482 CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD ​ 178,690 ​ 134,137 ​ 93,655 CASH AND CASH EQUIVALENTS AT END OF PERIOD ​ $ 258,874 ​ $ 178,690 ​ $ 134,137 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ SUPPLEMENTAL DISCLOSURE OF NON-CASH INVESTING AND FINANCING ACTIVITIES: ​ ​ ​ Unpaid property and equipment ​ $ 5,937 ​ $ 4,355 ​ $ 1,818 Unpaid technology licenses ​ $ — ​ $ — ​ $ 100 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION: ​ ​ ​ Cash paid (received) for income taxes, net (Note 11) ​ $ ( 1,973 ) ​ $ 21,327 ​ $ 7,437 ​ The accompanying notes are an integral part of these consolidated financial statements. ​ 39 Table of Contents POWER INTEGRATIONS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS 1. THE COMPANY: Power Integrations, Inc. (“Power Integrations” or the “Company”), incorporated in California on March 25, 1988, and reincorporated in Delaware in December 1997, designs, develops, manufactures and markets analog and mixed-signal integrated circuits (ICs) and other electronic components and circuitry used in high-voltage power conversion. The Company’s products are used in power converters that convert electricity from a high-voltage source to the type of power required for a specified downstream use. A large percentage of the Company’s products are ICs used in AC-DC power supplies, which convert the high-voltage AC from a wall outlet to the low-voltage DC required by most electronic devices. Power supplies incorporating the Company’s products are used with all manner of electronic products including mobile phones, computing and networking equipment, appliances, electronic utility meters, battery-powered tools, industrial controls, and “home-automation,” or “internet of things” applications such as networked thermostats, power strips and other building-automation and security devices. The Company also supplies high-voltage LED drivers, which are AC-DC ICs specifically designed for lighting applications that utilize light-emitting diodes. In 2018, the Company introduced a new category of power-conversion ICs: a family of motor-driver ICs addressing brushless DC (BLDC) motors used in refrigerators, HVAC systems, ceiling fans and other consumer-appliance and light commercial applications. The Company also offers high-voltage gate drivers—either standalone ICs or circuit boards containing ICs, electrical isolation components and other circuitry—used to operate high-voltage switches such as insulated-gate bipolar transistors (IGBTs) and silicon-carbide (SiC) MOSFETs. These combinations of switches and drivers are used for power conversion in high-power applications (i.e., power levels ranging from a few kilowatts up to gigawatts) such as industrial motors, solar- and wind-power systems, electric vehicles and high-voltage DC transmission systems. ​ 2. SIGNIFICANT ACCOUNTING POLICIES AND RECENT ACCOUNTING PRONOUNCEMENTS: Significant Accounting Policies and Estimates Segment Reporting The Company is organized and operates as one reportable segment, the design, development, manufacture and marketing of integrated circuits and related components for use primarily in the high-voltage power conversion markets. The Company’s chief operating decision maker, the Chief Executive Officer, reviews financial information presented on a consolidated basis for purposes of making operating decisions and assessing financial performance. Principles of Consolidation The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries after elimination of all intercompany transactions and balances. Estimates The preparation of financial statements in conformity with U.S. Generally Accepted Accounting Principles (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. On an ongoing basis, the Company evaluates its estimates, including those related to revenue recognition and allowances for receivables and inventories. These estimates are based on historical facts and various other factors, which the Company believes to be reasonable at the time the estimates are made. However, as the effects of future events cannot be determined with precision, actual results could differ significantly from management’s estimates. Revenue Recognition The Company applies the provisions of Accounting Standards Codification (ASC) 606-10, Revenue from Contracts with Customers , and all related appropriate guidance. The Company recognizes revenue under the core principle to depict the transfer of control to the Company’s customers in an amount reflecting the consideration the Company expects to be entitled. In order to achieve that core principle, the Company applies the following five-step approach: (1) identify 40 Table of Contents the contract with a customer, (2) identify the performance obligations in the contract, (3) determine the transaction price, (4) allocate the transaction price to the performance obligations in the contract, and (5) recognize revenue when a performance obligation is satisfied. Product revenues consist of sales to original equipment manufacturers, or OEMs, merchant power supply manufacturers and distributors. The Company considers customer purchase orders, which in some cases are governed by master sales agreements, to be the contracts with a customer. In situations where sales are to a distributor, the Company has concluded that its contracts are with the distributor as the Company holds a contract bearing enforceable rights and obligations only with the distributor. As part of its consideration of the contract, the Company evaluates certain factors including the customer’s ability to pay (or credit risk). For each contract, the Company considers the promise to transfer products, each of which is distinct, to be the identified performance obligations. In determining the transaction price the Company evaluates whether the price is subject to refund or adjustment to determine the net consideration to which the Company expects to be entitled. As the Company’s standard payment terms are less than one year, the Company has elected the practical expedient under ASC 606-10-32-18 to not assess whether a contract has a significant financing component. The Company allocates the transaction price to each distinct product based on their relative standalone selling price. The product price as specified on the purchase order is considered the standalone selling price as it is an observable input which depicts the price as if sold to a similar customer in similar circumstances. Revenue is recognized when control of the product is transferred to the customer (i.e., when the Company’s performance obligation is satisfied), which typically occurs at shipment. Further, in determining whether control has transferred, the Company considers if there is a present right to payment and legal title, along with risks and rewards of ownership having transferred to the customer. Frequently, the Company receives orders for products to be delivered over multiple dates that may extend across several reporting periods. The Company invoices for each delivery upon shipment and recognizes revenues for each distinct product delivered, assuming transfer of control has occurred. As scheduled delivery dates are within one year, under the optional exemption provided by ASC 606-10-50-14 revenues allocated to future shipments of partially completed contracts are not disclosed. The Company has also elected the practical expedient under ASC 340-40-25-4 to expense commissions when incurred as the amortization period of the commission asset the Company would have otherwise recognized is less than one year. Sales to international customers that are shipped from the Company’s facility outside of the United States are pursuant to EX Works, or EXW, shipping terms, meaning that control of the product transfers to the customer upon shipment from the Company’s foreign warehouse. Sales to international customers that are shipped from the Company’s facility in California are pursuant to Delivered at Frontier, or DAF, shipping terms. As such, control of the product passes to the customer when the shipment reaches the destination country and revenue is recognized upon the arrival of the product in that country. Shipments to customers in the Americas are pursuant to Free on Board, or FOB, point of origin shipping terms meaning that control is passed to the customer upon shipment. Sales to most distributors are made under terms allowing certain price adjustments and limited rights of return (known as “stock rotation”) of the Company’s products held in their inventory or upon sale to their end customers. Revenue from sales to distributors is recognized upon the transfer of control to the distributor. Frequently, distributors need to sell at a price lower than the standard distribution price in order to win business. At the time the distributor invoices its customer or soon thereafter, the distributor submits a “ship and debit” price adjustment claim to the Company to adjust the distributor’s cost from the standard price to the pre-approved lower price. After the Company verifies that the claim was pre-approved, a credit memo is issued to the distributor for the ship and debit claim. In determining the transaction price, the Company considers ship and debit price adjustments to be variable consideration. Such price adjustments are estimated using the expected value method based on an analysis of actual ship and debit claims, at the distributor and product level, over a period of time considered adequate to account for current pricing and business trends. Historically, actual price adjustments for ship and debit claims relative to those estimated and included when determining the transaction price have not materially differed. Stock rotation rights grant the distributor the ability to return certain specified amounts of inventory. Stock rotation adjustments are an additional form of variable consideration and are also estimated using the expected value method based on historical return rates. Historically, distributor stock rotation adjustments have not been material. Sales to certain distributors are made under terms that do not include rights of return or price concessions after the product is shipped to the distributor. Accordingly, upon application of steps one through five above, product revenue is recognized upon shipment and transfer of control. 41 Table of Contents The Company generally provides an assurance warranty that its products will substantially conform to the published specifications for twelve months from the date of shipment. The Company’s liability is limited to either a credit equal to the purchase price or replacement of the defective part. Returns under warranty have historically been immaterial. As such, the Company does not record a specific warranty reserve or consider activities related to such warranty, if any, to be a separate performance obligation. Inventories Inventories (which consist of costs associated with the purchases of wafers from domestic and offshore foundries and of packaged components from offshore assembly manufacturers, as well as internal labor and overhead associated with the testing of both wafers and packaged components) are stated at the lower of cost (first-in, first-out) or market. Provisions, when required, are made to reduce inventories to their estimated net realizable values. Income Taxes Income-tax expense is an estimate of current income taxes payable or refundable in the current fiscal year based on reported income before income taxes. Deferred income taxes reflect the effect of temporary differences and carry-forwards that are recognized for financial reporting and income tax purposes. The Company accounts for income taxes under the provisions of ASC 740, Income Taxe s. Under the provisions of ASC 740, deferred tax assets and liabilities are recognized based on the differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases, utilizing the tax rates that are expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The Company recognizes valuation allowances to reduce any deferred tax assets to the amount that it estimates will more likely than not be realized based on available evidence and management’s judgment. The Company limits the deferred tax assets recognized related to certain officers’ compensation to amounts that it estimates will be deductible in future periods based upon Internal Revenue Code Section 162(m). In the event that the Company determines, based on available evidence and management judgment, that all or part of the net deferred tax assets will not be realized in the future, it would record a valuation allowance in the period the determination is made. In addition, the calculation of tax liabilities involves significant judgment in estimating the impact of uncertainties in the application of complex tax laws. Resolution of these uncertainties in a manner inconsistent with the Company’s expectations could have a material impact on the Company’s results of operations and financial position. Goodwill and Intangible Assets Goodwill and the Company’s domain name are evaluated in accordance with ASC 350-10, Goodwill and Other Intangible Assets, and an impairment analysis is conducted on an annual basis, or sooner if indicators exist for a potential impairment. In accordance with ASC 360-10, Accounting for the Impairment or Disposal of Long-Lived Assets , long-lived assets, such as property and equipment and intangible assets, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to estimated undiscounted future cash flows expected to be generated by the asset. If the carrying amount of an asset exceeds its estimated future cash flows, an impairment charge is recognized by the amount by which the carrying amount of the asset exceeds the fair value of the asset. Cash and Cash Equivalents The Company considers cash invested in highly liquid financial instruments with maturities of three months or less at the date of purchase to be cash equivalents. Marketable Securities The Company generally holds securities until maturity; however, they may be sold under certain circumstances including, but not limited to, when necessary for the funding of acquisitions and other strategic investments. As a result, the Company classifies its investment portfolio as available-for-sale. The Company classifies all investments with a 42 Table of Contents maturity date greater than three months at the date of purchase as short-term marketable securities in its consolidated balance sheet. As of December 31, 2020, and December 31, 2019, the Company’s marketable securities consisted primarily of commercial paper, corporate bonds, government securities and/or other high-quality commercial securities. Employee Benefits Plan The Company sponsors a 401(k) tax-deferred savings plan for all employees in the United States who meet certain eligibility requirements. Participants may contribute up to the amount allowable as a deduction for federal income tax purposes. The Company is not required to contribute; however, the Company contributes a certain percentage of employee annual salaries on a discretionary basis, not to exceed an established threshold. The Company provided for a contribution of approximately $ 1.8 million, $ 1.4 million and $ 1.3 million in 2020, 2019 and 2018, respectively. Retirement Benefit Obligations (Pension) The Company recognizes the over-funded or under-funded status of a defined benefit pension or post-retirement plan as an asset or liability in the accompanying consolidated balance sheets. Actuarial gains and losses are recorded in accumulated other comprehensive loss, a component of stockholders’ equity, and are amortized as a component of net periodic cost over the remaining estimated service period of participants. Foreign Currency Risk and Foreign Currency Translation As of December 31, 2020, the Company’s primary transactional currency was U.S. dollars; in addition, the Company holds cash in Swiss francs and euros to fund the operations of the Company’s Swiss subsidiary. The foreign exchange rate fluctuation between the U.S. dollar versus the Swiss franc and euro is recorded in other income in the consolidated statements of income. Gains and losses arising from the remeasurement of non-functional currency balances are recorded in other income in the accompanying consolidated statements of income. The Company realized a foreign exchange transaction loss of $ 0.5 million, $ 0.3 million and $ 0.1 million in 2020, 2019, and 2018 respectively. The functional currencies of the Company’s other subsidiaries are the local currencies. Accordingly, all assets and liabilities are translated into U.S. dollars at the current exchange rates as of the applicable balance sheet date. Revenues and expenses are translated at the average exchange rate prevailing during the period. Cumulative gains and losses from the translation of the foreign subsidiaries’ financial statements have been included in stockholders’ equity. Warranty The Company generally warrants that its products will substantially conform to the published specifications for 12 months from the date of shipment. The Company’s liability is limited to either a credit equal to the purchase price or replacement of the defective part. Returns under warranty have historically been immaterial, and as a result, the Company does not record a specific warranty reserve. Advertising Advertising costs are expensed as incurred and amounted to $ 1.2 million, $ 1.4 million and $ 1.2 million in 2020, 2019 and 2018, respectively. Research and Development Research and development costs are expensed as incurred. Indemnifications The Company sells products to its distributors under contracts, collectively referred to as Distributor Sales Agreements (DSA). Each DSA contains the relevant terms of the contractual arrangement with the distributor, and generally includes certain provisions for indemnifying the distributor against losses, expenses, and liabilities from damages that may be awarded against the distributor in the event the Company’s products are found to infringe upon a patent, copyright, trademark, or other proprietary right of a third party (Customer Indemnification). The DSA generally limits the 43 Table of Contents scope of and remedies for the Customer Indemnification obligations in a variety of industry-standard respects, including, but not limited to, limitations based on time and geography, and a right to replace an infringing product. The Company also, from time to time, has granted a specific indemnification right to individual customers. The Company believes its internal development processes and other policies and practices limit its exposure related to such indemnifications. In addition, the Company requires its employees to sign a proprietary information and inventions agreement, which assigns the rights to its employees’ development work to the Company. To date, the Company has not had to reimburse any of its distributors or customers for any losses related to these indemnifications and no material claims were outstanding as of December 31, 2020. For several reasons, including the lack of prior indemnification claims and the lack of a monetary liability limit for certain infringement cases, the Company cannot determine the maximum amount of potential future payments, if any, related to such indemnifications. Adoption of New Accounting Standards In June 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update 2016-13, Financial Instruments – Credit Losses (Topic 326) , which modifies the measurement of expected credit losses on certain financial instruments. In addition, for available-for-sale debt securities, the standard eliminates the concept of other-than-temporary impairment and requires the recognition of an allowance for credit losses rather than reductions in the amortized cost of the securities. The Company adopted the new standard in the first quarter of 2020, effective January 1, 2020, using the modified-retrospective approach. For available-for-sale debt securities, the Company has made a policy election to present separately accrued interest receivable within prepaid expenses and other current assets on the consolidated balance sheet. Upon adoption, there was no impact on the Company’s consolidated financial statements. ​ 44 Table of Contents 3. COMPONENTS OF THE COMPANY’S CONSOLIDATED BALANCE SHEETS: Accounts Receivable ​ ​ ​ ​ ​ ​ ​ ​ December 31, December 31, (In thousands) ​ 2020 ​ 2019 Accounts receivable trade ​ $ 66,703 ​ $ 61,036 Accrued ship and debit ​ ( 26,435 ) ​ ( 33,475 ) Allowance for stock rotation and rebate ​ ( 3,931 ) ​ ( 2,524 ) Allowance for credit losses ​ ​ ( 427 ) ​ ​ ( 763 ) Total ​ $ 35,910 ​ $ 24,274 ​ The Company maintains an allowance for estimated credit losses resulting from the inability of customers to make required payments. This allowance is established using estimates formulated by the Company’s management based upon factors such as the composition of the accounts receivable aging, historical losses, changes in payments patterns, customer creditworthiness, and current economic trends. Receivables determined to be uncollectible are written off and deducted from the allowance. ​ ​ ​ ​ ​ ​ ​ Allowance for Credit Losses ​ ​ Year Ended (In thousands) December 31, 2020 Beginning balance ​ $ ( 763 ) Provision for credit loss expense ​ ( 621 ) Receivables written off ​ 198 Recoveries collected ​ 759 Ending balance ​ $ ( 427 ) ​ Inventories ​ ​ ​ ​ ​ ​ ​ ​ December 31, December 31, (In thousands) ​ 2020 ​ 2019 Raw materials ​ $ 32,131 ​ $ 39,058 Work-in-process ​ 39,469 ​ 25,982 Finished goods ​ 31,278 ​ 25,340 Total ​ $ 102,878 ​ $ 90,380 ​ Property and Equipment ​ ​ ​ ​ ​ ​ ​ ​ December 31, December 31, (In thousands) ​ 2020 ​ 2019 Land ​ $ 22,189 ​ $ 21,790 Construction-in-progress ​ 34,886 ​ 18,604 Building and improvements ​ 64,808 ​ 55,785 Machinery and equipment ​ 202,698 ​ 168,576 Computer software and hardware and office furniture and fixtures ​ 55,591 ​ 52,265 ​ ​ 380,172 ​ 317,020 Accumulated depreciation ​ ( 213,984 ) ​ ( 200,401 ) Total ​ $ 166,188 ​ $ 116,619 ​ Depreciation expense for property and equipment for fiscal years ended December 31, 2020, 2019 and 2018, was approximately $ 23.7 million, $ 19.2 million and $ 18.9 million, respectively, and was determined using the straight-line method over the following useful lives: ​ ​ ​ ​ ​ Building and improvements 4 - 40 years Machinery and equipment 2 - 8 years Computer software and hardware and office furniture and fixtures 4 - 7 years ​ 45 Table of Contents Total property and equipment (excluding accumulated depreciation) located in the United States at December 31, 2020, 2019 and 2018, was approximately $ 167.0 million, $ 160.7 million and $ 167.6 million, respectively. In 2020, 2019 and 2018 approximately 14 %, 14 % and 12 %, respectively, of total property and equipment (excluding accumulated depreciation) was held in Thailand by one of the Company’s subcontractors. Also in 2020, approximately 14 % of total property and equipment was held by one of the Company’s subcontractors in Malaysia. No other country held 10 % or more of total property and equipment in the periods presented. Accumulated Other Comprehensive Loss Changes in accumulated other comprehensive loss for the three years ended December 31, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Unrealized Gains ​ ​ ​ ​ ​ ​ ​ ​ and Losses on ​ ​ ​ ​ Foreign ​ ​ ​ ​ ​ Available-for-Sale ​ Defined Benefit ​ Currency ​ ​ ​ (In thousands) ​ Securities ​ Pension Items ​ Items ​ Total Balance at January 1, 2018 ​ $ ( 427 ) ​ $ ( 1,237 ) ​ $ ( 475 ) ​ $ ( 2,139 ) Other comprehensive income (loss) before reclassifications ​ 161 ​ 401 ​ ( 236 ) ​ 326 Amounts reclassified from accumulated other comprehensive loss ​ — ​ 124 (1) — ​ 124 Other comprehensive income ​ 161 ​ 525 ​ ( 236 ) ​ 450 Balance at December 31, 2018 ​ ( 266 ) ​ ( 712 ) ​ ( 711 ) ​ ( 1,689 ) Other comprehensive income (loss) before reclassifications ​ 849 ​ ( 1,839 ) ​ ( 518 ) ​ ( 1,508 ) Amounts reclassified from accumulated other comprehensive loss ​ — ​ 67 (1) — ​ 67 Other comprehensive loss ​ 849 ​ ( 1,772 ) ​ ( 518 ) ​ ( 1,441 ) Balance at December 31, 2019 ​ 583 ​ ( 2,484 ) ​ ( 1,229 ) ​ ( 3,130 ) Other comprehensive income (loss) before reclassifications ​ 307 ​ 636 ​ ( 183 ) ​ 760 Amounts reclassified from accumulated other comprehensive loss ​ — ​ 207 (1) — ​ 207 Other comprehensive income ​ 307 ​ 843 ​ ( 183 ) ​ 967 Balance at December 31, 2020 ​ $ 890 ​ $ ( 1,641 ) ​ $ ( 1,412 ) ​ $ ( 2,163 ) (1) This component of accumulated other comprehensive loss is included in the computation of net periodic pension cost for the years ended December 31, 2020, 2019 and 2018. ​ 4. FAIR VALUE MEASUREMENTS: ASC 820-10, Fair Value Measurements , clarifies that fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, ASC 820-10 establishes a three-tier value hierarchy, which prioritizes the inputs used in measuring fair value as follows: (Level 1) observable inputs such as quoted prices for identical assets in active markets; (Level 2) inputs other than the quoted prices in active markets that are observable either directly or indirectly; and (Level 3) unobservable inputs in which there is little or no market data, which requires the Company to develop its own assumptions. This hierarchy requires the Company to use observable market data, when available, and to minimize the use of unobservable inputs when determining fair value. The Company’s cash equivalents and investment instruments are classified within Level 1 or Level 2 of the fair-value hierarchy because they are valued using quoted market prices, broker or dealer quotations, or alternative pricing sources with reasonable levels of price transparency. The type of instrument valued based on quoted market prices in active markets primarily includes money market securities. This type of instrument is generally classified within Level 1 of the fair-value hierarchy. The types of instruments valued based on other observable inputs (Level 2 of the fair-value hierarchy) include investment-grade corporate bonds and commercial paper. Such types of investments are valued by using a multi-dimensional relational model, the inputs are primarily benchmark yields, reported trades, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers, and reference data including market research publications. The Company does not hold any instruments that would be classified within Level 3 of the fair-value hierarchy. 46 Table of Contents The fair value hierarchy of the Company’s cash equivalents and marketable securities at December 31, 2020, and 2019, was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurement at ​ ​ December 31, 2020 ​ ​ ​ Quoted Prices in ​ ​ ​ ​ ​ ​ ​ Active Markets for ​ Significant Other ​ ​ ​ ​ ​ Identical Assets ​ Observable Inputs (In thousands) ​ Total Fair Value ​ (Level 1) ​ (Level 2) Corporate securities ​ $ 146,658 ​ $ — ​ $ 146,658 Commercial paper ​ 253,855 ​ — ​ 253,855 Money market funds ​ 1,634 ​ 1,634 ​ — Total ​ $ 402,147 ​ $ 1,634 ​ $ 400,513 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurement at ​ ​ December 31, 2019 ​ ​ ​ Quoted Prices in ​ ​ ​ ​ ​ ​ ​ Active Markets for ​ Significant Other ​ ​ ​ ​ ​ Identical Assets ​ Observable Inputs (In thousands) ​ Total Fair Value ​ (Level 1) ​ (Level 2) Corporate securities ​ $ 232,398 ​ $ — ​ $ 232,398 Commercial paper ​ 146,955 ​ — ​ 146,955 Money market funds ​ 2,983 ​ 2,983 ​ — Total ​ $ 382,336 ​ $ 2,983 ​ $ 379,353 ​ The Company did no t transfer any investments between level 1 and level 2 of the fair value hierarchy in the years ended December 31, 2020, and 2019. 5. MARKETABLE SECURITIES: Amortized cost and estimated fair market value of marketable securities classified as available-for-sale (excluding cash equivalents) at December 31, 2020, were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortized ​ Gross Unrealized ​ Estimated Fair (In thousands) Cost Gains Losses Market Value Investments due in 3 months or less: ​ ​ ​ ​ Commercial paper ​ $ 43,660 ​ $ — ​ $ — ​ $ 43,660 Corporate securities ​ ​ 19,846 ​ ​ 44 ​ ​ — ​ ​ 19,890 Total ​ 63,506 ​ 44 ​ — ​ 63,550 Investments due in 4-12 months: ​ ​ ​ ​ Corporate securities ​ 125,922 ​ 846 ​ — ​ 126,768 Total ​ 125,922 ​ 846 ​ — ​ 126,768 Total marketable securities ​ $ 189,428 ​ $ 890 ​ $ — ​ $ 190,318 ​ The Company did not have any investments due in twelve months or greater as of December 31, 2020. Accrued interest receivable was $ 0.8 million at December 31, 2020 and was recorded within prepaid expenses and other current assets on the condensed consolidated balance sheet. 47 Table of Contents Amortized cost and estimated fair market value of marketable securities classified as available-for-sale (excluding cash equivalents) at December 31, 2019, were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortized ​ Gross Unrealized ​ Estimated Fair (In thousands) Cost Gains Losses Market Value Investments due in 3 months or less: ​ ​ ​ ​ Corporate securities ​ $ 15,934 ​ $ 18 ​ $ — ​ $ 15,952 Total ​ 15,934 ​ 18 ​ — ​ 15,952 Investments due in 4-12 months: ​ ​ ​ ​ Corporate securities ​ 71,223 ​ 269 ​ — ​ 71,492 Total ​ 71,223 ​ 269 ​ — ​ 71,492 Investments due in 12 months or greater: ​ ​ ​ ​ Corporate securities ​ 144,658 ​ 302 ​ ( 6 ) ​ 144,954 Total ​ 144,658 ​ 302 ​ ( 6 ) ​ 144,954 Total marketable securities ​ $ 231,815 ​ $ 589 ​ $ ( 6 ) ​ $ 232,398 ​ Accrued interest receivable was $ 1.3 million at December 31, 2019 and was recorded within prepaid expenses and other current assets on the condensed consolidated balance sheet. ​ As of December 31, 2020, the Company had no marketable securities classified as available-for-sale (excluding cash equivalents) in a continuous unrealized loss position for which an allowance for credit losses was not recorded. The following table summarizes marketable securities classified as available-for-sale (excluding cash equivalents) in a continuous unrealized loss position for which an allowance for credit losses was not recorded at December 31, 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Less Than 12 Months ​ 12 Months or Longer ​ Total ​ Estimated Gross Estimated Gross Estimated Gross ​ ​ Fair Market ​ Unrealized ​ Fair Market ​ Unrealized ​ Fair Market ​ Unrealized (In thousands) ​ Value ​ Losses ​ Value ​ Losses ​ Value ​ Losses December 31, 2019 ​ ​ ​ ​ ​ ​ Corporate securities ​ $ 13,069 ​ $ ( 6 ) ​ $ — ​ $ — ​ $ 13,069 ​ $ ( 6 ) Total marketable securities ​ $ 13,069 ​ $ ( 6 ) ​ $ — ​ $ — ​ $ 13,069 ​ $ ( 6 ) ​ The weighted average interest rate of investments at December 31, 2020 and 2019, was approximately 0.89 % and 2.17 %, respectively. In the year ended December 31, 2020, no unrealized losses on marketable securities were recognized in income. ​ 6. GOODWILL AND INTANGIBLE ASSETS: The carrying amount of goodwill as of December 31, 2020 and 2019 was $ 91.8 million with no changes to goodwill in any of the respective fiscal years. Intangible assets consist primarily of developed technology, acquired licenses, customer relationships, trade name, domain name, in-process R&D and patent rights, and are reported net of accumulated amortization. The Company amortizes the cost of all intangible assets over the shorter of the estimated useful life or the term of the developed technology, customer relationships, technology licenses and in-place leases, which range from two to twelve years , with the exception of $ 1.3 million paid to acquire an internet domain name. The Company acquired the rights to the internet domain name www.power.com , which is now the Company’s primary domain name; the cost to acquire the domain name has been recorded as an intangible asset and will not be amortized as it has an indefinite useful life. Amortization of acquired intangible assets was approximately $ 4.4 million, $ 5.2 million and $ 5.3 million in the years ended December 31, 2020, 2019 and 2018, respectively. The Company does not believe there is any significant residual value associated with the following intangible assets: 48 Table of Contents ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ December 31, 2019 ​ ​ ​ Accumulated ​ ​ ​ ​ Accumulated ​ ​ (In thousands) ​ Gross ​ Amortization ​ Net ​ Gross ​ Amortization ​ Net Domain name ​ $ 1,261 ​ $ — ​ $ 1,261 ​ $ 1,261 ​ $ — ​ $ 1,261 Developed technology ​ 37,960 ​ ( 29,126 ) ​ 8,834 ​ 37,960 ​ ( 25,933 ) ​ 12,027 Customer relationships ​ 16,700 ​ ( 15,687 ) ​ 1,013 ​ 20,030 ​ ( 18,098 ) ​ 1,932 Technology licenses ​ 1,926 ​ ( 528 ) ​ 1,398 ​ 1,926 ​ ( 281 ) ​ 1,645 Total intangible assets ​ $ 57,847 ​ $ ( 45,341 ) ​ $ 12,506 ​ $ 61,177 ​ $ ( 44,312 ) ​ $ 16,865 ​ The estimated future amortization expense related to definite-lived intangible assets at December 31, 2020, is as follows: ​ ​ ​ ​ ​ Estimated ​ ​ Amortization Fiscal Year ​ (In thousands) 2021 ​ $ 3,494 2022 ​ 2,415 2023 ​ 2,173 2024 ​ 1,279 2025 ​ 832 Thereafter ​ 1,052 Total ​ $ 11,245 ​ ​ ​ 7. STOCK PLANS AND SHARE BASED COMPENSATION: The share and per share information for all periods presented in this Form 10-K has been adjusted for the effect of the August 2020 stock split. Refer to Note 10, Earnings Per Share , in this Form 10-K for details. Stock Plans As of December 31, 2020, the Company had three stock-based compensation plans (the “Plans”) which are described below. 2007 Equity Incentive Plan The 2007 Equity Incentive Plan (2007 Plan) was adopted by the board of directors on September 10, 2007, and approved by the stockholders on November 7, 2007, as an amendment and restatement of the 1997 Stock Option Plan (1997 Plan). The 2007 Plan provides for the grant of incentive stock options, non-statutory stock options, restricted stock awards, restricted stock unit (RSU) awards, stock appreciation rights, performance-based (PSU) awards, long-term performance based (PRSU) awards and other stock awards to employees, directors and consultants. Pursuant to the 2007 Plan, the exercise price for incentive stock options and non-statutory stock options is generally at least 100 % of the fair market value of the underlying shares on the date of grant. Options generally vest over 48 months measured from the date of grant. Options generally expire no later than ten years after the date of grant, subject to earlier termination upon an optionee’s cessation of employment or service. The 2007 Plan expired in September 2017 with no further grants to be made under this plan; however previous grants under this plan shall remain outstanding until they are exercised, vest, forfeited or expire. 2016 Incentive Award Plan The 2016 Incentive Award Plan (2016 Plan) was adopted by the board of directors on March 17, 2016 and approved by the stockholders on May 13, 2016. The 2016 Plan provides for the grant of RSU awards, PSU awards and PRSU awards. No other forms of equity-based awards, including stock options and stock appreciation rights, may be granted under the 2016 Plan. As of December 31, 2020, 2.2 million awards have been issued and approximately 2.8 million shares of common stock remain available for future grant under the 2016 Plan. 49 Table of Contents 1997 Employee Stock Purchase Plan Under the 1997 Employee Stock Purchase Plan (Purchase Plan), eligible employees may apply accumulated payroll deductions, which may not exceed 15 % of an employee’s compensation, to the purchase of shares of the Company’s common stock at periodic intervals. The purchase price of stock under the Purchase Plan is equal to 85 % of the lower of (i) the fair market value of the Company’s common stock on the first day of each offering period, or (ii) the fair market value of the Company’s common stock on the purchase date (as defined in the Purchase Plan). Each offering period consists of one purchase period of approximately six months ' duration. An aggregate of 7.0 million shares of common stock were reserved for issuance to employees under the Purchase Plan. As of December 31, 2020, of the shares reserved for issuance, 6.6 million shares had been purchased and 0.4 million shares were reserved for future issuance under the Purchase Plan. Shares Reserved As of December 31, 2020, the Company had approximately 3.4 million shares of common stock reserved for future grant under all stock plans. Stock-Based Compensation The Company applies the provisions of ASC 718-10, Stock Compensation . Under the provisions of ASC 718-10, the Company recognizes the fair value of stock-based compensation in its financial statements over the requisite service period of the individual grants, which generally equals a four-year vesting period. The Company uses estimates of volatility, expected term, risk-free interest rate, dividend yield and forfeitures in determining the fair value of these awards and the amount of compensation expense to recognize. The Company uses the straight-line method to amortize all stock awards granted over the requisite service period of the award. The following table summarizes the stock-based compensation expense recognized in accordance with ASC 718-10 for the years ended December 31, 2020, 2019 and 2018: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, (In thousands) 2020 2019 2018 Cost of revenues ​ $ 1,963 ​ $ 1,237 ​ $ 1,097 Research and development ​ 10,378 ​ 8,423 ​ 7,688 Sales and marketing ​ 6,290 ​ 5,015 ​ 4,729 General and administrative ​ 12,281 ​ 8,672 ​ 8,066 Total stock-based compensation expense ​ $ 30,912 ​ $ 23,347 ​ $ 21,580 ​ The following table summarizes total compensation expense related to unvested awards not yet recognized, net of expected forfeitures, and the weighted average period over which it is expected to be recognized as of December 31, 2020: ​ ​ ​ ​ ​ ​ ​ Unrecognized Compensation Weighted Average ​ ​ Expense for Unvested ​ Remaining Recognition ​ ​ Awards ​ Period ​ ​ (In thousands) ​ (In years) Long-term performance-based awards ​ $ 5,810 1.64 Restricted stock units ​ 34,654 2.62 Purchase plan ​ 202 0.08 Total unrecognized compensation expense ​ $ 40,666 ​ Stock-based compensation expense in the year ended December 31, 2020, was approximately $ 30.9 million (comprising approximately $ 18.7 million related to restricted stock units, $ 10.2 million related to performance-based awards and $ 2.0 million related to the Company’s Purchase Plan). Stock-based compensation expense in the year ended December 31, 2019, was approximately $ 23.3 million (comprising approximately $ 17.5 million related to restricted stock units, $ 4.1 million related to performance-based awards and $ 1.7 million related to the Company’s Purchase Plan). 50 Table of Contents Stock-based compensation expense in the year ended December 31, 2018, was approximately $ 21.6 million comprising approximately $ 16.6 million related to restricted stock units, $ 3.4 million related to performance-based awards and $ 1.6 million related to the Company’s Purchase Plan). The Company did not grant stock options in the years ended December 31, 2020, 2019 and 2018, and therefore no fair-value assumptions are reported. The fair value of employees’ stock purchase rights under the Purchase Plan was estimated using the Black-Scholes model with the following weighted-average assumptions used during the three years ended December 31, 2020, 2019 and 2018: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ 2020 ​ 2019 ​ 2018 Risk-free interest rates ​ 0.90 % ​ ​ 2.28 % ​ ​ 1.94 % Expected volatility rates ​ 47 % ​ ​ 37 % ​ ​ 31 % Expected dividend yield ​ 0.78 % ​ ​ 0.91 % ​ ​ 0.89 % Expected term of purchase rights (in years) ​ 0.50 ​ ​ 0.50 ​ ​ 0.50 Weighted-average estimated fair value of purchase rights ​ $ 15.73 ​ ​ $ 19.39 ​ ​ $ 17.33 ​ ​ A summary of stock options outstanding as of December 31, 2020, and activity during three years then ended, is presented below: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Average ​ ​ ​ ​ ​ ​ ​ Weighted- ​ Remaining ​ ​ ​ ​ ​ ​ ​ Average ​ Contractual ​ Aggregate ​ ​ Shares ​ Exercise ​ Term ​ Intrinsic Value ​ (In thousands) Price (In years) (In thousands) Outstanding at January 1, 2018 1,022 ​ $ 14.52 ​ Granted — ​ — ​ Exercised ( 352 ) ​ $ 11.30 ​ Forfeited or expired — ​ — ​ Outstanding at December 31, 2018 670 ​ $ 16.21 ​ Granted — ​ — ​ Exercised ( 335 ) ​ $ 12.98 ​ Forfeited or expired — ​ — ​ Outstanding at December 31, 2019 335 ​ $ 19.44 ​ Granted — ​ — ​ Exercised ( 243 ) ​ $ 18.99 ​ Forfeited or expired — ​ — ​ Outstanding at December 31, 2020 92 ​ $ 20.63 1.05 ​ $ 5,643 Vested and Exercisable at December 31, 2020 92 ​ ​ ​ 1.05 ​ $ 5,643 ​ The total intrinsic value of options exercised during the year ended December 31, 2020, 2019 and 2018, was $ 9.1 million, $ 8.3 million and $ 7.5 million, respectively. The following table summarizes the stock options outstanding at December 31, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Options Outstanding ​ Options Exercisable ​ ​ Weighted Average Weighted ​ Weighted ​ ​ ​ ​ Remaining ​ Average ​ ​ ​ Average (shares in thousands) ​ Options ​ Contractual Term ​ Exercise ​ Options ​ Exercise Range of Exercise Prices ​ Outstanding ​ (in years) ​ Price ​ Exercisable ​ Price $ 18.48 - $ 19.75 ​ 28 ​ 0.38 ​ $ 18.77 ​ 28 ​ $ 18.77 $ 21.44 - $ 21.44 64 1.35 ​ $ 21.44 64 ​ $ 21.44 ​ 92 1.05 ​ $ 20.63 92 ​ $ 20.63 ​ 51 Table of Contents PSU Awards Under the performance-based awards program, the Company grants awards in the performance year in an amount equal to twice the target number of shares to be issued if the maximum performance metrics are met. The number of shares that are released at the end of the performance year can range from zero to 200 % of the target number depending on the Company’s performance. The performance metrics of this program are annual targets consisting of a combination of net revenue, non-GAAP operating earnings and strategic goals. As the net revenue, non-GAAP operating income and strategic goals are considered performance conditions, expense associated with these awards, net of estimated forfeitures, is recognized over the service period based on an assessment of the achievement of the performance targets. The fair value of these PSUs is determined using the fair value of the Company’s common stock on the date of the grant, reduced by the discounted present value of dividends expected to be declared before the awards vest. If the performance conditions are not achieved, no compensation cost is recognized and any previously recognized compensation is reversed. A summary of PSU awards outstanding as of December 31, 2020, and activity during the three years then ended, is presented below: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ ​ ​ ​ ​ Weighted- ​ Average ​ ​ ​ ​ ​ ​ ​ Average ​ Remaining ​ Aggregate ​ ​ Shares ​ Grant Date Fair ​ Contractual Term ​ Intrinsic Value ​ (In thousands) Value Per Share (In years) (In thousands) Outstanding at January 1, 2018 158 ​ $ 32.00 ​ Granted 178 ​ $ 31.44 ​ Vested ( 158 ) ​ $ 32.00 ​ Forfeited or canceled ( 126 ) ​ $ 31.44 ​ Outstanding at December 31, 2018 52 ​ $ 31.44 ​ Granted 185 ​ $ 35.06 ​ Vested ( 52 ) ​ $ 31.44 ​ Forfeited or canceled ( 64 ) ​ $ 35.06 ​ Outstanding at December 31, 2019 121 ​ $ 35.06 ​ Granted 150 ​ $ 46.31 ​ Vested ( 121 ) ​ $ 35.06 ​ Forfeited or canceled — ​ ​ — ​ Outstanding at December 31, 2020 150 ​ $ 46.27 — ​ $ 12,219 Outstanding and expected to vest at December 31, 2020 150 ​ ​ ​ — ​ $ 12,219 ​ The grant-date fair value of PSU awards released, which were fully vested, in the years ended December 31, 2020, 2019 and 2018 was approximately $ 4.2 million, $ 1.6 million and $ 5.1 million, respectively. PRSU Awards (Long-term Performance Based) The Company’s PRSU program provides for the issuance of PRSUs which will vest based on the Company’s performance measured against the PRSU Plan’s established revenue targets. The PRSUs were granted in an amount equal to twice the target number of shares to be issued if the maximum performance metrics are met. The actual number of shares the recipient receives is determined at the end of a three-year performance period based on results achieved versus the Company’s performance goals, and may range from zero to 200 % of the target number. Recipients of a PRSU award generally must remain employed by the Company on a continuous basis through the end of the applicable three-year performance period in order to receive shares subject to that award. The performance goals for PRSUs granted in fiscal 2020, 2019 and 2018 were based on the Company’s annual revenue growth over the respective three-year performance period. Expense associated with these awards, net of estimated forfeitures, is recorded throughout the year based on an assessment of the expected achievement of the performance targets. If the performance conditions are not achieved, no compensation cost is recognized and any previously recognized compensation is reversed. 52 Table of Contents A summary of PRSU awards outstanding as of December 31, 2020, and activity during the three years then ended, is presented below: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted-Average ​ Aggregate ​ ​ ​ ​ Weighted-Average ​ Remaining ​ Intrinsic ​ ​ Shares ​ Grant Date Fair ​ Contractual Term ​ Value ​ (In thousands) Value Per Share (In years) (In thousands) Outstanding at January 1, 2018 368 ​ $ 26.40 ​ Granted 144 ​ $ 29.95 ​ Vested ( 76 ) ​ $ 26.23 ​ Forfeited or canceled ( 10 ) ​ $ 21.63 ​ Outstanding at December 31, 2018 426 ​ $ 27.74 ​ Granted 144 ​ $ 34.09 ​ Vested ( 140 ) ​ $ 21.63 ​ Forfeited or canceled ( 143 ) ​ $ 31.50 ​ Outstanding at December 31, 2019 287 ​ $ 32.03 ​ Granted 152 ​ $ 49.67 ​ Vested — ​ ​ — ​ Forfeited or canceled ( 138 ) ​ $ 29.95 ​ Outstanding at December 31, 2020 301 ​ $ 41.90 1.51 ​ $ 24,637 Outstanding and expected to vest at December 31, 2020 272 ​ ​ ​ 1.54 ​ $ 22,279 ​ In January 2020 it was determined that no shares subject to the PRSUs granted in 2017 vested in aggregate; thus no shares were released to the Company’s executives in 2020. The grant-date fair value of PRSU awards released, which were fully vested, in the years ended December 31, 2019 and 2018 was approximately $ 3.0 million and $ 2.0 million , respectively. RSU Awards RSUs granted to employees typically vest ratably over a four-year period, and are converted into shares of the Company’s common stock upon vesting on a one-for-one basis subject to the employee’s continued service to the Company over that period. The fair value of RSUs is determined using the fair value of the Company’s common stock on the date of the grant, reduced by the discounted present value of dividends expected to be declared before the awards vest. Compensation expense is recognized on a straight-line basis over the requisite service period of each grant adjusted for estimated forfeitures. 53 Table of Contents A summary of RSU awards outstanding as of December 31, 2020, and activity during the three years then ended, is presented below: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted-Average ​ Aggregate ​ ​ ​ ​ Weighted-Average ​ Remaining ​ Intrinsic ​ ​ Shares ​ Grant Date Fair ​ Contractual Term ​ Value ​ (In thousands) Value Per Share (In years) (In thousands) Outstanding at January 1, 2018 1,896 ​ $ 27.76 ​ Granted 550 ​ $ 31.43 ​ Vested ( 592 ) ​ $ 26.89 ​ Forfeited ( 64 ) ​ $ 29.72 ​ Outstanding at December 31, 2018 1,790 ​ $ 29.10 ​ Granted 582 ​ $ 34.90 ​ Vested ( 603 ) ​ $ 28.10 ​ Forfeited ( 50 ) ​ $ 31.72 ​ Outstanding at December 31, 2019 1,719 ​ $ 31.33 ​ Granted 439 ​ $ 44.82 ​ Vested ( 599 ) ​ $ 30.25 ​ Forfeited ( 41 ) ​ $ 36.77 ​ Outstanding at December 31, 2020 1,518 ​ $ 35.51 1.42 ​ $ 124,239 Outstanding and expected to vest at December 31, 2020 1,423 ​ ​ ​ 1.36 ​ $ 116,475 ​ The grant-date fair value of RSUs vested in the years ended December 31, 2020, 2019 and 2018, was approximately $ 18.1 million, $ 16.9 million and $ 15.9 million, respectively. ​ 8. SIGNIFICANT CUSTOMERS AND GEOGRAPHIC NET REVENUES: Customer Concentration The Company’s top ten customers accounted for approximately 62 %, 54 % and 56 % of revenues in 2020, 2019 and 2018, respectively. A significant portion of these revenues are attributable to sales of the Company’s products to distributors of electronic components. These distributors sell the Company’s products to a broad, diverse range of end users, including OEMs and merchant power supply manufacturers. Sales to distributors in 2020, 2019 and 2018 were $ 367.7 million, $ 304.6 million and $ 313.9 million, respectively. Direct sales to OEMs and power-supply manufacturers accounted for the remainder. The following customers represented 10% or more of the Company’s net revenues for the respective years : ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, Customer 2020 ​ 2019 ​ 2018 Avnet ​ 19 % ​ 11 % ​ 14 % Honestar Technologies Co., Ltd. 11 % ​ * ​ ​ * ​ ________________________ *Total customer revenue was less than 10 % of net revenues. No other customers accounted for 10% or more of the Company’s net revenues in the periods presented. Concentration of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consisted principally of cash investments and trade receivables. The Company does not have any off-balance-sheet credit exposure related to its customers. As of December 31, 2020 and December 31, 2019, 90 % and 63 % of accounts receivable were concentrated with the Company’s top ten customers, respectively. 54 Table of Contents The following customers represented 10 % or more of accounts receivable: ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, Customer 2020 ​ 2019 Powertech Distribution Ltd. 10 % ​ 10 % Avnet 50 % ​ * ​ ________________________ *Total customer accounts receivable was less than 10% of net accounts receivables. No other customers accounted for 10 % or more of the Company’s accounts receivable in the periods presented. Geographic Net Revenues The Company markets its products globally through its sales personnel and a worldwide network of independent sales representatives and distributors. Geographic net revenues based on “bill to” customer locations were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, (In thousands) 2020 2019 2018 United States of America ​ $ 11,065 ​ $ 10,662 ​ $ 15,315 Hong Kong/China ​ 306,938 ​ 237,341 ​ 218,752 Taiwan ​ 21,650 ​ 36,297 ​ 43,081 Korea ​ 40,059 ​ 30,395 ​ 33,877 Western Europe (excluding Germany) ​ 33,564 ​ 36,025 ​ 49,834 Japan ​ 17,453 ​ 15,496 ​ 19,897 Germany ​ 23,242 ​ 20,197 ​ 14,403 Other ​ 34,347 ​ 34,256 ​ 20,796 Total net revenues ​ $ 488,318 ​ $ 420,669 ​ $ 415,955 ​ ​ ​ 9. COMMON STOCK REPURCHASES AND CASH DIVIDENDS: Common Stock Repurchases Over the years the Company’s board of directors has authorized the use of funds to repurchase shares of the Company’s common stock, including $ 110.0 million in 2018, with repurchases to be executed according to pre-defined price/volume guidelines. In 2018, 2019 and 2020 the Company purchased approximately 3,144,000 , 242,000 and 63,000 shares, respectively, for approximately $ 103.2 million, $ 7.3 million and $ 2.6 million, respectively. As of December 31, 2020, the Company had $ 41.3 million available for future stock repurchases, which has no expiration date. Authorization of future stock repurchase programs is at the discretion of the board of directors and will depend on the Company’s financial condition, results of operations, capital requirements and business conditions as well as other factors. Common Stock Dividend The following table presents the quarterly dividends declared per share of the Company’s common stock for the periods indicated: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ 2020 2019 2018 First Quarter ​ $ 0.095 ​ $ 0.085 ​ $ 0.080 Second Quarter ​ $ 0.105 ​ $ 0.085 ​ $ 0.080 Third Quarter ​ $ 0.110 ​ $ 0.085 ​ $ 0.080 Fourth Quarter ​ $ 0.110 ​ $ 0.095 ​ $ 0.080 ​ The Company paid a total of approximately $ 25.1 million, $ 20.5 million and $ 18.8 million in cash dividends during 2020, 2019 and 2018, respectively. In January 2018, the Company’s board of directors declared a $ 0.080 per share quarterly dividend for each quarter in 2018. In January 2019, the Company’s board of directors declared four quarterly cash dividends of $ 0.085 per share to be paid to stockholders of record at the end of each quarter in 2019. In October 2019, the Company’s board of directors raised the cash dividends per share with the declaration of five cash dividends, consisting of (a) a dividend of $ 0.01 per 55 Table of Contents share to be paid to stockholders of record at the end of the fourth quarter in 2019, that was in addition to the dividend of $ 0.085 per share to be paid to stockholders of record at the end of the fourth quarter in 2019 previously declared by the board in January 2019, and (b) a dividend of $ 0.095 per share to be paid to stockholders of record at the end of each quarter in 2020. In April 2020, the Company’s board of directors raised the cash dividends with the declaration of three cash dividends of $ 0.105 per share (in lieu of the $ 0.095 per share previously announced in October 2019) to be paid to stockholders of record at the end of each of the second, third and fourth quarter in 2020. In July 2020, the Company’s board of directors raised the cash dividends further with the declaration of two cash dividends of $ 0.11 per share (in lieu of the $ 0.105 per share announced in April 2020) to be paid to stockholders of record at the end of each of the third and fourth quarter in 2020. In January 2021, the Company’s board of directors raised the quarterly cash dividend again by $ 0.02 per share with the declaration of four cash dividends of $ 0.13 per share to be paid to stockholders of record at the end of each quarter in 2021. ​ ​ 10. EARNINGS PER SHARE: Basic earnings per share are calculated by dividing net income by the weighted-average shares of common stock outstanding during the period. Diluted earnings per share are calculated by dividing net income by the weighted-average shares of common stock and dilutive common equivalent shares outstanding during the period. Dilutive common equivalent shares included in this calculation consist of dilutive shares issuable upon the assumed exercise of outstanding common stock options, the assumed vesting of outstanding restricted stock units, the assumed issuance of awards under the stock purchase plan and contingently issuable performance-based awards, as computed using the treasury stock method. A summary of the earnings per share calculation is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, (In thousands, except per share amounts) 2020 2019 2018 Basic earnings per share: ​ ​ ​ Net income ​ $ 71,176 ​ $ 193,468 ​ $ 69,984 Weighted-average common shares ​ 59,657 ​ 58,534 ​ 58,912 Basic earnings per share ​ $ 1.19 ​ $ 3.31 ​ $ 1.19 Diluted earnings per share: (1) ​ ​ ​ Net income ​ $ 71,176 ​ $ 193,468 ​ $ 69,984 Weighted-average common shares ​ 59,657 ​ 58,534 ​ 58,912 Effect of dilutive awards: ​ ​ ​ Employee stock plans ​ 1,188 ​ 1,098 ​ 1,382 Diluted weighted-average common shares ​ 60,845 ​ 59,632 ​ 60,294 Diluted earnings per share ​ $ 1.17 ​ $ 3.24 ​ $ 1.16 (1) The Company includes the shares underlying performance-based awards in the calculation of diluted earnings per share if the performance conditions have been satisfied as of the end of the reporting period and excludes such shares when the necessary conditions have not been met. The Company has included in the 2020, 2019 and 2018 calculations those shares that were contingently issuable upon the satisfaction of the performance conditions as of the end of the respective periods. In the years ended December 31, 2020, 2019, and 2018, no outstanding stock awards were determined to be anti-dilutive and therefore were excluded from the computation of diluted earnings per share. In July 2020, the Company’s board of directors approved a two -for-one stock split in the form of a stock dividend, payable on August 18, 2020, to stockholders of record as of the close of business on August 14, 2020. The Company’s stockholders received one additional share of common stock for each share of common stock held on August 14, 2020 . The share and per share information for all periods presented in this Form 10-K has been adjusted for the effect of the stock split. ​ 56 Table of Contents 11. PROVISION (BENEFIT) FOR INCOME TAXES: Income Taxes The Company accounts for income taxes under the provisions of ASC 740, Income Taxes . Under the provisions of ASC 740, deferred tax assets and liabilities are recognized based on the differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases, utilizing the tax rates that are expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. U.S. and foreign components of income before income taxes were: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, (In thousands) 2020 2019 2018 U.S. operations ​ $ ( 6,252 ) ​ $ 82,692 ​ $ ( 6,529 ) Foreign operations ​ 81,503 ​ 139,722 ​ 66,293 Total income before income taxes ​ $ 75,251 ​ $ 222,414 ​ $ 59,764 ​ The components of the provision (benefit) for income taxes are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, (In thousands) 2020 2019 2018 Current provision (benefit): ​ ​ ​ Federal ​ $ 2,788 ​ $ 18,293 ​ $ ( 6,382 ) State ​ ( 181 ) ​ 184 ​ 4 Foreign ​ 1,677 ​ 1,293 ​ 938 ​ ​ 4,284 ​ 19,770 ​ ( 5,440 ) Deferred provision (benefit): ​ ​ ​ Federal ​ 348 ​ 9,683 ​ ( 4,593 ) State ​ — ​ — ​ — Foreign ​ ( 557 ) ​ ( 507 ) ​ ( 187 ) ​ ​ ( 209 ) ​ 9,176 ​ ( 4,780 ) Total ​ $ 4,075 ​ $ 28,946 ​ $ ( 10,220 ) ​ The provision (benefit) for income taxes differs from the amount that would result by applying the applicable federal income tax rate to income before income taxes, as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ 2020 ​ 2019 ​ 2018 Provision (benefit) computed at Federal statutory rate 21.0 % ​ 21.0 % ​ 21.0 % Business tax credits ( 7.4 ) ​ ( 2.4 ) ​ ( 9.1 ) ​ Stock-based compensation ( 0.1 ) ​ ( 0.2 ) ​ ( 2.2 ) ​ Foreign income taxed at different rate ( 22.0 ) ​ ( 12.7 ) ​ ( 25.0 ) ​ GILTI inclusion 10.7 ​ 6.2 ​ 10.6 ​ U.S. Tax Act - transition tax — ​ 0.1 ​ ( 16.2 ) ​ Deferred tax asset and liability adjustment 0.3 ​ — ​ — ​ Valuation allowance 2.6 ​ 0.8 ​ 2.8 ​ Other 0.3 ​ 0.2 ​ 1.0 ​ Total 5.4 % ​ 13.0 % ​ ( 17.1 ) % ​ The Company’s effective tax rate is impacted by the geographic distribution of the Company’s world-wide earnings in lower-tax jurisdictions, federal research tax credits and the recognition of excess tax benefits related to share-based payments. These benefits were partially offset by foreign income subject to U.S. tax, known as global intangible low-taxed income. The Company’s primary jurisdiction where foreign earnings are derived is the Cayman Islands, which is a non-taxing jurisdiction. Income earned in other foreign jurisdictions was not material. The Company has not been granted any incentivized tax rates and does not operate under any tax holidays in any jurisdiction. Additionally, in 2018 the Company’s effective tax rate was favorably impacted by revisions to the Tax Act resulting in a $ 9.7 million income tax benefit. 57 Table of Contents The components of the net deferred income tax assets (liabilities) were as follows: ​ ​ ​ ​ ​ ​ ​ ​ December 31, (In thousands) ​ 2020 ​ 2019 Deferred tax assets: ​ ​ Other reserves and accruals ​ $ 3,707 ​ $ 3,099 Tax credit carry-forwards ​ 20,713 ​ 18,968 Stock compensation ​ 1,494 ​ 1,644 Capital losses ​ 158 ​ 157 Net operating loss ​ 2,303 ​ 899 Other ​ 1,023 ​ 1,000 Valuation allowance ​ ( 24,160 ) ​ ( 20,822 ) ​ ​ 5,238 ​ 4,945 Deferred tax liabilities: ​ ​ Depreciation ​ ( 1,974 ) ​ ( 2,273 ) ​ ​ ( 1,974 ) ​ ( 2,273 ) Net deferred tax assets ​ $ 3,264 ​ $ 2,672 ​ In assessing the realizability of deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. Management considers the scheduled reversal of deferred tax liabilities and projected future taxable income. In the event that the Company determines, based on available evidence and management judgment, that all or part of the net deferred tax assets will not be realized in the future, the Company would record a valuation allowance in the period the determination is made. In addition, the calculation of tax liabilities involves significant judgment in estimating the impact of uncertainties in the application of complex tax laws. Resolution of these uncertainties in a manner inconsistent with the Company’s expectations could have a material impact on its results of operations and financial position. As of December 31, 2020, the Company continues to maintain a valuation allowance primarily as a result of capital losses for federal purposes, and on its California, New Jersey and Canada deferred tax assets as the Company believes that it is not more likely than not that the deferred tax assets will be fully realized. As of December 31, 2020, the Company had utilized all of its federal research and development tax credit carryforwards. As of December 31, 2020, the Company had California research and development tax credit carryforwards of approximately $ 30.2 million (there is no expiration of research and development tax credit carryforwards for the state of California) and California net operating losses of $ 44.7 million which will begin to expire in 2032 . As of December 31, 2020, the Company had Canadian scientific research and experimental development tax credit carryforwards of approximately $ 3.4 million and New Jersey research and experimental development tax credit carryforwards of approximately $ 0.7 million, which will start to expire in 2030 and 2026 , respectively. The Tax Act signed into law on December 22, 2017, generally allows companies to repatriate accumulated foreign earnings without incurring additional U.S. federal taxes beginning after December 31, 2017. Local foreign and U.S. states taxes may still be incurred upon repatriation. The Company has not provided for U.S. taxes on its undistributed earnings of foreign subsidiaries. The determination of the future tax consequences of the remittance of these earnings is not practicable. 58 Table of Contents Unrecognized Tax Benefits The Company applies the provisions of ASC 740-10, relating to accounting for uncertain income taxes. Reconciliation of the beginning and ending amount of unrecognized tax benefits: ​ ​ ​ ​ ​ Unrecognized (In thousands) ​ Tax Benefits Unrecognized Tax Benefits Balance at January 1, 2018 ​ $ 16,683 Gross Increase for Tax Positions of Current Year ​ 1,994 Gross Decrease for Tax Positions of Prior Years ​ ( 70 ) Unrecognized Tax Benefits Balance at December 31, 2018 ​ 18,607 Gross Increase for Tax Positions of Current Year ​ 1,379 Gross Decrease for Tax Positions of Prior Years ​ ( 937 ) Unrecognized Tax Benefits Balance at December 31, 2019 ​ 19,049 Gross Increase for Tax Positions of Current Year ​ 2,002 Gross Decrease for Tax Positions of Prior Years ​ — Unrecognized Tax Benefits Balance at December 31, 2020 ​ $ 21,051 ​ The Company’s total unrecognized tax benefits as of December 31, 2020, 2019 and 2018, were $ 21.1 million, $ 19.0 million and $ 18.6 million, respectively. An income tax benefit of $ 11.1 million, net of valuation allowance adjustments, would be recorded if these unrecognized tax benefits are recognized. The Company cannot reasonably estimate the amount of the unrecognized tax benefit that could be adjusted in the next twelve months. The Company’s continuing practice is to recognize interest and/or penalties related to income tax matters in income tax expense. The Company had accrued interest and penalties of $ 0.1 million as of both December 31, 2020 and 2019, which have been recorded in long-term income taxes payable in the accompanying consolidated balance sheets. As of December 31, 2020, the Company has concluded all U.S. federal income tax matters for the years through 2012. However, due to tax attributes, the IRS may calculate tax adjustments for subsequent years for positions taken prior to 2012. There are currently no pending income tax audits. On July 27, 2015, in Altera Corp. v. Commissioner, the U.S. Tax Court issued an opinion related to the treatment of stock-based compensation expense in an intercompany cost-sharing arrangement. A final decision was issued by the Tax Court in December 2015. In February 2016, the Commissioner appealed the Tax Court decision. On July 24, 2018, the U.S. Ninth Circuit Court of Appeals reversed the U.S. Tax Court’s decision Altera Corp. v. Commissioner; the reversal was subsequently withdrawn. On June 7, 2019, the Ninth Circuit Court of Appeals overturned the U.S. Tax Court decision; finding that the Government had adequately supported in the record that stock-based compensation should be treated as an intangible development cost in a cost-sharing arrangement and Treasury’s position on the issue was not a policy change, holding stock-based compensation to be a compensable cost under IRC Section 482. On February 10, 2020, Altera filed a petition for a writ of certiorari asking the Supreme Court to review the Ninth Circuit’s decision. The Supreme Court’s denied the petition for certiorari, and thus the Ninth Circuit’s decision stands. The decision above does not impact the Company as it treats stock-based compensation as a compensable cost under IRC Section 482. ​ 12. LEASES AND COMMITMENTS: Facilities and Leases The Company owns its main executive, administrative, manufacturing and technical offices in San Jose, California. The Company also owns a research and development facility in New Jersey, a design center in Germany and a test facility in Switzerland. The Company’s leases consist of operating leases for administrative office spaces, research-and-development facilities and sales offices in various countries around the world. Effective January 1, 2019, the Company adopted Accounting Standards Update 2016-02, Leases (Topic 842), using the optional transition method. The Company determines if an arrangement is a lease at inception. Some lease agreements contain lease and non-lease components, which are accounted for as a single lease component. Total lease expense was $ 2.7 million, $ 2.5 million and $ 2.2 million in the years ended December 31, 2020, 2019 and 2018, respectively, while short-term and variable lease expenses were not material during these periods. 59 Table of Contents Balance sheet information related to leases was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, (In thousands) ​ Balance Sheet Classification ​ 2020 ​ 2019 Right-of-use assets ​ ​ ​ ​ ​ ​ Operating lease assets ​ Other assets ​ $ 10,295 ​ $ 9,521 Lease liabilities ​ ​ ​ ​ Current operating lease liabilities ​ Other accrued liabilities ​ $ 2,682 ​ $ 1,954 Non-current operating lease liabilities ​ Other liabilities ​ 7,345 ​ 7,031 Total ​ ​ ​ $ 10,027 ​ $ 8,985 ​ Initial lease terms are determined at commencement and may include options to extend or terminate the lease when it is reasonably certain the Company will exercise the option. Remaining lease terms range from one to eight years , some of which include options to extend for up to six years , and some of which include options to terminate within one year . Leases with an initial term of twelve months or less are not recorded on the balance sheet. As the Company’s leases do not provide an implicit rate, the present value of future lease payments is determined using the Company’s incremental borrowing rate based on information available at commencement date. ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, Lease term and discount rate ​ 2020 ​ 2019 Weighted average remaining lease term ​ 4.2 years ​ 4.8 years Weighted average discount rate 3.3 % ​ 3.9 % ​ Supplemental cash flows information related to leases was as follow: ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, (In thousands) ​ 2020 ​ 2019 Cash paid for amounts included in the measurement of lease liabilities: ​ ​ ​ ​ ​ Operating cash flows from operating leases ​ $ 2,459 ​ $ 2,964 Right-of-use assets obtained in exchange for new operating lease obligations ​ $ 2,947 ​ $ 4,884 ​ Future minimum lease payments under all non-cancelable lease agreements as of December 31, 2020, are as follows: ​ ​ ​ ​ ​ December 31, (In thousands) ​ 2020 2021 ​ $ 2,964 2022 ​ 2,840 2023 ​ 2,477 2024 ​ 1,334 2025 ​ 342 Thereafter ​ 830 Total future minimum lease payments ​ 10,787 Less imputed interest ​ ( 760 ) Total ​ $ 10,027 ​ Purchase Obligations At December 31, 2020, the Company had no non-cancelable purchase obligations that were due beyond one year. ​ 13. LEGAL PROCEEDINGS AND CONTINGENCIES: From time to time in the ordinary course of business, the Company becomes involved in lawsuits, or customers and distributors may make claims against the Company. In accordance with ASC 450-10, Contingencies , the Company makes a provision for a liability when it is both probable that a liability has been incurred and the amount of the loss can be reasonably estimated. 60 Table of Contents On April 1, 2016, Opticurrent, LLC filed a complaint against the Company in the United States District Court for the Eastern District of Texas alleging that the Company infringed one patent pertaining to transistor switch devices and seeking damages for the alleged infringement. The Company filed a motion to transfer the case to the Northern District of California, which the Court granted, and the case was assigned to a new judge in San Francisco following the transfer. On December 21, 2018, the Court granted the Company’s challenge to Opticurrent’s damages expert but denied the Company’s motion for summary judgment. Following a trial in February 2019, a jury issued a finding of direct infringement by the Company but found that the Company did not induce infringement, and awarded Opticurrent damages of $ 6.7 million. The Company challenged those findings in post-trial proceedings, and the Court granted one of the Company’s post-trial motions, reducing the damages award to $ 1.2 million. Although the Court of Appeals affirmed the original findings and the reduced damages award, the Company believes it has strong defenses, and intends to continue to vigorously defend itself against Opticurrent’s claims, including through a pending motion to set aside the judgment in view of a disclaimer that Opticurrent made during reexamination proceedings, which has been fully briefed and argued, with rulings expected in the coming months. On June 19, 2019, Opticurrent, LLC filed a follow-on lawsuit in the United States District Court for the Northern District of California accusing more of the Company’s products of infringement and seeking damages for the alleged infringement of the same claim of the same patent asserted in the parties’ prior litigation, as described above. Limited discovery has taken place, but proceedings are currently stayed pending resolution of the Company’s motion to set aside the judgment in the parties’ prior litigation, and no schedule has yet been set for expert discovery, dispositive motions, or trial. The Company believes it has strong defenses, and intends to vigorously defend itself against Opticurrent’s claims, with appeals to follow if necessary. On January 6, 2020, the Company filed a complaint against CogniPower LLC in the United States District Court for the District of Delaware for infringement of two of the Company’s patents and seeking a declaration of non-infringement with respect to patents that CogniPower had charged the Company’s customers with infringing , based on customer use of the Company’s products. In response, CogniPower filed a motion to dismiss the Company’s declaratory judgment claims on the basis that CogniPower had not threatened the Company directly with suit. That motion was granted, so CogniPower’s claims for infringement initially went forward separately in their lawsuit against the Company’s customers in the District of Delaware, but the Company filed a motion to intervene in that lawsuit and received a ruling allowing the Company to intervene in CogniPower’s customer lawsuit on February 1, 2021. Fact discovery and claim construction proceedings are now under way, but the Company believes it has strong claims and defenses, and intends to vigorously defend itself against CogniPower’s claims against the Company’s technology, with appeals to follow if necessary. The Company is unable to predict the outcome of legal proceedings with certainty, and there can be no assurance that Power Integrations will prevail in the above-mentioned unsettled litigations. These litigations, whether or not determined in Power Integrations’ favor or settled, will be costly and will divert the efforts and attention of the Company’s management and technical personnel from normal business operations, potentially causing a material adverse effect on the business, financial condition and operating results. Currently, the Company is not able to estimate a loss or a range of loss for the ongoing litigation disclosed above, however adverse determinations in litigation could result in monetary losses, the loss of proprietary rights, subject the Company to significant liabilities, require Power Integrations to seek licenses from third parties or prevent the Company from licensing the technology, any of which could have a material adverse effect on the Company’s business, financial condition and operating results. 14. RETIREMENT PLANS: The Company sponsors a defined benefit pension plan (Pension Plan) for its Swiss subsidiary in accordance with the legal requirements of Switzerland. The plan assets, which provide benefits in the event of an employee’s retirement, death or disability, are held in legally autonomous trustee-administered funds that are subject to Swiss law. Benefits are based on the employee’s age, years of service and salary, and the plan is financed by contributions by both the employee and the Company. The net periodic benefit cost of the Pension Plan was not material to the Company’s financial statements during the years ended December 31, 2020, 2019 and 2018. At December 31, 2020, the projected benefit obligation was $ 16.6 million, the plan assets were $ 9.7 million and the net pension liability was $ 6.9 million. As of December 31, 2019, the projected benefit obligation was $ 14.8 million, the plan assets were $ 8.2 million, and the net pension liability was $ 6.6 million. The Company has recorded the unfunded amount as a liability in its consolidated balance sheet at December 31, 61 Table of Contents 2020 and 2019, under the other liabilities caption. The Company expects to make contributions to the Pension Plan of approximately $ 0.4 million during 2021. The unrealized actuarial loss on pension benefits, net of tax, at December 31, 2020, 2019 and 2018 was $ 1.6 million, $ 2.5 million and $ 0.7 million, respectively. These amounts were reflected in Note 3 under the caption accumulated other comprehensive loss. In accordance with the Compensation-Retirement Benefits Topic of ASC 715-20, Defined Benefits Plan , the Company recognizes the over-funded or under-funded status of its defined post-retirement plan as an asset or liability in its statement of financial position. The Company measured the plan assets and benefit obligations as of the date of the fiscal year-end. ​ 15. BANK LINE OF CREDIT: On July 27, 2016, the Company entered into a credit agreement with a bank (the "Credit Agreement") that provides the Company with a $ 75.0 million revolving line of credit to use for general corporate purposes with a $ 20.0 million sub-limit for the issuance of standby and trade letters of credit. The Credit Agreement was amended on April 30, 2018, to extend the termination date from July 26, 2019, to April 30, 2022, with all other terms remaining the same. The Company’s ability to borrow under the revolving line of credit is conditioned upon the Company’s compliance with specified covenants, including reporting and financial covenants, primarily a minimum cash requirement and a debt to earnings ratio. The Credit Agreement terminates on April 30, 2022; all advances under the revolving line of credit will become due on such date, or earlier in the event of a default. The Company was compliant with all covenants and had no advances outstanding under the Credit Agreement. ​ 16. SELECTED QUARTERLY INFORMATION (Unaudited): The following tables set forth certain data from the Company’s consolidated statements of income for each of the quarters in the years ended December 31, 2020 and 2019. The unaudited quarterly consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements contained herein and include all adjustments that the Company considers necessary for a fair presentation of such information when read in conjunction with the Company’s annual audited consolidated financial statements and notes thereto appearing elsewhere in this report. The operating results for any quarter are not necessarily indicative of the results for any subsequent period or for the entire fiscal year. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ (unaudited) ​ Dec. 31, ​ Sept. 30, ​ June 30, ​ Mar. 31, ​ Dec. 31, ​ Sept. 30, ​ June 30, ​ Mar. 31, (In thousands, except per share data) 2020 2020 2020 2020 2019(1) 2019 ​ 2019 2019 Net revenues $ 150,693 ​ $ 121,129 ​ $ 106,832 ​ $ 109,664 ​ $ 114,457 ​ $ 114,159 ​ $ 102,865 ​ $ 89,188 Gross profit 74,005 ​ 59,569 ​ 53,536 ​ 56,480 ​ 58,225 ​ 58,131 ​ 51,572 ​ 45,474 Net income $ 27,278 ​ $ 14,820 ​ $ 13,192 ​ $ 15,886 ​ $ 158,291 ​ $ 17,099 ​ $ 10,845 ​ $ 7,233 Earnings per share (2) ​ ​ ​ ​ ​ ​ ​ Basic $ 0.46 ​ $ 0.25 ​ $ 0.22 ​ $ 0.27 ​ $ 2.69 ​ $ 0.29 ​ $ 0.19 ​ $ 0.13 Diluted $ 0.45 ​ $ 0.24 ​ $ 0.22 ​ $ 0.27 ​ $ 2.64 ​ $ 0.29 ​ $ 0.19 ​ $ 0.13 Shares used in per share calculation (2) ​ ​ ​ ​ ​ ​ ​ Basic 59,879 ​ 59,823 ​ 59,712 ​ 59,204 ​ 58,854 ​ 58,770 ​ 58,594 ​ 57,902 Diluted 61,176 ​ 60,852 ​ 60,624 ​ 60,268 ​ 60,010 ​ 59,732 ​ 59,404 ​ 58,892 (1) In October 2019, the Company entered into a favorable litigation settlement with ON Semiconductor Corporation which resulted in a $ 169.0 million net gain. (2) In July 2020, the Company’s board of directors approved a two -for-one stock split in the form of a stock dividend, payable on August 18, 2020, to stockholders of record as of the close of business on August 14, 2020. The Company’s stockholders received one additional share of common stock for each share of common stock held on August 14, 2020. The share and per share information for all periods presented in this Form 10-K has been adjusted for the effect of the stock split ( Refer to Note 10, Earnings Per Share , in this Form 10-K for details ) . ​ 62 Table of Contents Schedule II Valuation and Qualifying Accounts The Company maintains an allowance for the distributors’ ship and debit credits relating to the sell-through of the Company’s products. This reserve is established using the Company’s historical ship and debit amounts and levels of inventory in the distributor channels. The following is a summary of the activity in the allowance for ship and debit credits: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance at Charged to ​ ​ ​ ​ ​ ​ Beginning of ​ Costs and ​ ​ ​ ​ Balance at End (In thousands) Period Expenses Deductions(1) of Period Allowance for ship and debit credits: ​ ​ ​ ​ ​ ​ ​ ​ Year ended December 31, 2018 ​ $ 39,486 ​ $ 242,068 ​ $ ( 241,436 ) ​ $ 40,118 Year ended December 31, 2019 ​ $ 40,118 ​ $ 230,278 ​ $ ( 236,921 ) ​ $ 33,475 Year ended December 31, 2020 ​ $ 33,475 ​ $ 257,765 ​ $ ( 264,805 ) ​ $ 26,435 (1) Deductions relate to ship and debit credits issued which adjust the sales price from the standard distribution price to the pre-approved lower price. Refer to Note 2, Significant Accounting Policies and Recent Accounting Pronouncements , for the Company’s revenue recognition policy, including the Company’s accounting for ship and debit claims. ​ 63 Table of Contents Item 9. Changes in and Disagreements with Accountants on Accounting and Financial Disclosure. Not applicable.