Monolithic Power Systems (MPWR) 10-K 1 Mar 21 2020 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 22, 2021	Jun. 30, 2020
Document Information [Line Items]
Entity Central Index Key	0001280452
Entity Registrant Name	MONOLITHIC POWER SYSTEMS INC
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2020
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Transition Report	false
Entity File Number	000-51026
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	77-0466789
Entity Address, Address Line One	5808 Lake Washington Blvd. NE
Entity Address, City or Town	Kirkland
Entity Address, State or Province	WA
Entity Address, Postal Zip Code	98033
City Area Code	425
Local Phone Number	296-9956
Title of 12(b) Security	Common Stock, par value $0.001 per share
Trading Symbol	MPWR
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 8,100,000,000
Entity Common Stock, Shares Outstanding		45,621,000

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 334,944	$ 172,960
Short-term investments	260,169	282,437
Accounts receivable, net	66,843	52,704
Inventories	157,062	127,500
Other current assets	22,980	19,605
Total current assets	841,998	655,206
Property and equipment, net	281,528	228,315
Goodwill	6,571	6,571
Deferred tax assets, net	18,556	17,193
Other long-term assets	59,838	49,090
Total assets	1,208,491	956,375
Current liabilities:
Accounts payable	38,169	27,271
Accrued compensation and related benefits	45,840	26,164
Other accrued liabilities	62,960	44,790
Total current liabilities	146,969	98,225
Income tax liabilities	37,062	37,596
Other long-term liabilities	57,873	47,063
Total liabilities	241,904	182,884
Commitments and contingencies
Stockholders’ equity:
Common stock and additional paid-in capital: $0.001 par value; shares authorized: 150,000; shares issued and outstanding: 45,267 and 43,616, respectively	657,701	549,517
Retained earnings	298,746	229,450
Accumulated other comprehensive income (loss)	10,140	(5,476)
Total stockholders’ equity	966,587	773,491
Total liabilities and stockholders’ equity	$ 1,208,491	$ 956,375

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parentheticals) - $ / shares shares in Thousands	Dec. 31, 2020	Dec. 31, 2019
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	150,000	150,000
Common stock, shares issued (in shares)	45,267	43,616
Common stock, shares outstanding (in shares)	45,267	43,616

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue	$ 844,452	$ 627,921	$ 582,382
Cost of revenue	378,498	281,596	259,714
Gross profit	465,954	346,325	322,668
Operating expenses:
Research and development	137,598	107,757	93,455
Selling, general and administrative	161,670	133,542	113,803
Litigation expense	7,804	2,464	1,922
Total operating expenses	307,072	243,763	209,180
Income from operations	158,882	102,562	113,488
Other income, net	10,460	10,558	4,994
Income before income taxes	169,342	113,120	118,482
Income tax expense	4,967	4,281	13,214
Net income	$ 164,375	$ 108,839	$ 105,268
Net income per share
Basic (in dollars per share)	$ 3.67	$ 2.52	$ 2.49
Diluted (in dollars per share)	$ 3.50	$ 2.38	$ 2.36
Weighted-average shares outstanding:
Basic (in shares)	44,840	43,165	42,247
Diluted (in shares)	47,014	45,763	44,602

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net income	$ 164,375	$ 108,839	$ 105,268
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	14,150	(1,706)	(7,082)
Change in unrealized gain (loss) on available-for-sale securities, net of tax of $(325), $(203) and $209, respectively	1,466	1,773	(274)
Other comprehensive income (loss), net of tax	15,616	67	(7,356)
Comprehensive income	$ 179,991	$ 108,906	$ 97,912

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Parentheticals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Change in unrealized gain (loss) on available-for-sale securities, tax	$ (325)	$ (203)	$ 209

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Cumulative Effect, Period of Adoption, Adjustment [Member]Common Stock Including Additional Paid in Capital [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member]Retained Earnings [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member]AOCI Attributable to Parent [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member]	Common Stock Including Additional Paid in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balance (in shares) at Dec. 31, 2017					41,614
Balance at Dec. 31, 2017	$ 0	$ 379	$ 0	$ 379	$ 376,586	$ 143,608	$ 1,813	$ 522,007
Net income					0	105,268	0	105,268
Other comprehensive income (loss)					0	0	(7,356)	(7,356)
Dividends and dividend equivalents declared					$ 0	(54,527)	0	(54,527)
Common stock issued under the employee equity incentive plan (in shares)					858
Common stock issued under the employee equity incentive plan					$ 10,637	0	0	10,637
Common stock issued under the employee stock purchase plan (in shares)					33
Common stock issued under the employee stock purchase plan					$ 3,028	0	0	3,028
Stock-based compensation expense					$ 60,657	0	0	60,657
Balance (in shares) at Dec. 31, 2018					42,505
Balance at Dec. 31, 2018					$ 450,908	194,728	(5,543)	640,093
Net income					0	108,839	0	108,839
Other comprehensive income (loss)					0	0	67	67
Dividends and dividend equivalents declared					$ 0	(74,117)	0	(74,117)
Common stock issued under the employee equity incentive plan (in shares)					1,083
Common stock issued under the employee equity incentive plan					$ 16,650	0	0	16,650
Common stock issued under the employee stock purchase plan (in shares)					28
Common stock issued under the employee stock purchase plan					$ 3,277	0	0	3,277
Stock-based compensation expense					$ 78,682	0	0	$ 78,682
Balance (in shares) at Dec. 31, 2019					43,616			43,616
Balance at Dec. 31, 2019					$ 549,517	229,450	(5,476)	$ 773,491
Net income					0	164,375	0	164,375
Other comprehensive income (loss)					0	0	15,616	15,616
Dividends and dividend equivalents declared					$ 0	(95,079)	0	(95,079)
Common stock issued under the employee equity incentive plan (in shares)					1,623
Common stock issued under the employee equity incentive plan					$ 18,767	0	0	18,767
Common stock issued under the employee stock purchase plan (in shares)					28
Common stock issued under the employee stock purchase plan					$ 3,819	0	0	3,819
Stock-based compensation expense					$ 85,598	0	0	$ 85,598
Balance (in shares) at Dec. 31, 2020					45,267			45,267
Balance at Dec. 31, 2020					$ 657,701	$ 298,746	$ 10,140	$ 966,587

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity (Parentheticals) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Dividends and dividend equivalents declared per share (in dollars per share)	$ 2	$ 1.60	$ 1.20

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net income	$ 164,375	$ 108,839	$ 105,268
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	19,186	14,867	12,311
Amortization of premium on available-for-sale securities	2,979	729	1,353
(Gain) loss on deferred compensation plan investments	(4,592)	(3,806)	255
Deferred taxes, net	(1,627)	(577)	(843)
Stock-based compensation expense	85,551	78,699	60,607
Other	(1,072)	(259)	22
Changes in operating assets and liabilities:
Accounts receivable	(14,123)	2,512	(18,079)
Inventories	(29,503)	8,865	(37,060)
Other assets	(3,003)	(10,204)	(1,075)
Accounts payable	10,410	3,048	871
Accrued compensation and related benefits	18,524	7,496	3,806
Income tax liabilities	747	(1,355)	6,923
Other accrued liabilities	19,951	7,449	7,092
Net cash provided by operating activities	267,803	216,303	141,451
Cash flows from investing activities:
Purchases of property and equipment	(55,639)	(95,806)	(22,526)
Proceeds from sales of property and equipment	29	9,268	0
Acquisition of in-place leases	0	(981)	0
Purchases of short-term investments	(334,947)	(212,562)	(99,199)
Proceeds from maturities and sales of short-term investments	357,092	135,801	109,131
Purchases of long-term investments	(3,316)	0	0
Proceeds from sales of long-term investments	300	250	2,000
Contributions to deferred compensation plan, net	(2,696)	(3,082)	(4,146)
Net cash used in investing activities	(39,177)	(167,112)	(14,740)
Cash flows from financing activities:
Property and equipment purchased on extended payment terms	(5,357)	(683)	(749)
Proceeds from common stock issued under the employee equity incentive plan	18,767	16,650	10,637
Proceeds from common stock issued under the employee stock purchase plan	3,819	3,277	3,028
Dividends and dividend equivalents paid	(88,786)	(67,294)	(47,475)
Net cash used in financing activities	(71,557)	(48,050)	(34,559)
Effect of change in exchange rates	4,926	(883)	(2,208)
Net increase in cash, cash equivalents and restricted cash	161,995	258	89,944
Cash, cash equivalents and restricted cash, beginning of period	173,076	172,818	82,874
Cash, cash equivalents and restricted cash, end of period	335,071	173,076	172,818
Supplemental disclosures for cash flow information:
Cash paid for taxes	1,405	10,700	7,134
Non-cash investing and financing activities:
Liability accrued for property and equipment purchases	7,839	7,803	1,737
Liability accrued for dividends and dividend equivalents	$ 27,507	$ 21,955	$ 16,319

Note 1 - Summary of Significant

Note 1 - Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Significant Accounting Policies [Text Block]	1. Business Monolithic Power Systems, Inc. (the “Company”) was incorporated in the State of California on August 22, 1997. November 17, 2004, Basis of Presentation The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. Intercompany accounts and transactions have been eliminated in consolidation. Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America (“GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, and reported amounts of revenue and expenses during the reporting period. Significant estimates and assumptions used in these consolidated financial statements primarily include those related to revenue recognition, inventory valuation, valuation of share-based awards, contingencies and income tax valuation allowances. Actual results could differ from these estimates and assumptions, and any such differences may The COVID- 19 not December 31, 2020 , As of the date of issuance of these consolidated financial statements, the Company is not . Certain Significant Risks and Uncertainties Financial instruments which potentially subject the Company to concentrations of credit risk consist primarily of cash equivalents, short-term and long-term investments and accounts receivable. The Company’s cash equivalents include short-term, highly liquid investments purchased with remaining maturities at the date of purchase of three may The Company does not may The Company participates in the dynamic high technology industry and believes that changes in any of the following areas could have a material adverse effect on its future financial position, results of operations or cash flows: advances and trends in new technologies and industry standards; competitive pressures in the form of new products or price reductions on current products; changes in product mix; changes in the overall demand for products offered by the Company; changes in third Foreign Currency In general, the functional currency of the Company’s international subsidiaries is the local currency. The primary subsidiaries are located in China, Taiwan and Europe, which utilize the Renminbi, the New Taiwan Dollar and the Euro as their currencies, respectively. Accordingly, assets and liabilities of the foreign subsidiaries are translated using exchange rates in effect at the end of the period. Revenue and costs are translated using average exchange rates for the period. The resulting translation adjustments are recorded in accumulated other comprehensive income (loss) on the Consolidated Balance Sheets. In addition, the Company incurs foreign currency exchange gain or loss related to certain intercompany transactions between the U.S. and its foreign subsidiaries that are denominated in a currency other than the functional currency. In connection with the settlement and remeasurement of the balances, the Company recorded foreign currency exchange gain (loss) of $(1.4) million, $(0.3) million and $1.0 million for the years ended December 31, 2020, 2019 2018, Cash Equivalents and Debt Investments The Company classifies all highly liquid investments with stated maturities of three may one Cash equivalents are stated at cost, which approximates fair market value. The Company’s short-term and long-term debt investments are classified as available-for-sale securities and are stated at their fair market value, with unrealized gains and losses recorded in accumulated other comprehensive income (loss) on the Consolidated Balance Sheets. Premiums and discounts on debt investments are generally amortized or accreted over the life of the related available-for-sale securities. Interest income is recognized when earned. The cost of investments sold is determined on a specific identification method. Available-for-sale investments are subject to impairment reviews when the fair value is below the amortized cost basis. If the Company determines that the decline in fair value below the amortized cost basis is due to credit-related factors, the impairment is recognized as an allowance on the Consolidated Balance Sheets with a corresponding adjustment to earnings. An impairment that is not not Equity Investments Equity investments in privately held companies without readily determinable fair values are accounted for under the measurement alternative, provided that the Company does not The Company monitors its non-marketable equity investments for impairment indicators, such as negative changes in industry and market conditions, financial performance, business prospects, and other relevant events and factors. If indicators exist for a security and the fair value is below the carrying amount, the Company writes down the security to fair value. Fair Value of Financial Instruments Fair value is defined as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining the fair value, the Company considers the principal or most advantageous market in which the Company would transact, as well as assumptions that market participants would use when pricing the assets or liabilities. Fair value is estimated by applying the following hierarchy, which prioritizes the inputs used to measure fair value into three ● Level 1 ● Level 2 not ● Level 3 Inventories Inventories are stated at the lower of standard cost (which approximates actual cost determined on a first first may may not Property and Equipment Property and equipment are stated at cost. Depreciation commences when an asset is placed in service and available for its intended use. Depreciation is computed using the straight-line method over the estimated useful lives of the assets. Buildings and building improvements have estimated useful lives of 20 to 40 years. Leasehold improvements are amortized over the shorter of the estimated useful lives or the lease period. Production equipment and software have estimated useful lives of three eight three five not Impairment of Long-Lived Assets The Company evaluates its long-lived assets other than goodwill for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not not Goodwill Goodwill represents the excess of the fair value of purchase consideration over the fair value of net tangible and identified intangible assets as of the date of acquisition. Goodwill is not The Company tests goodwill for impairment at least annually in the fourth may first not not No Deferred Compensation Plan The Company has a non-qualified, unfunded deferred compensation plan, which provides certain key employees, including executive officers, with the ability to defer the receipt of compensation in order to accumulate funds for retirement on a tax deferred basis. The Company does not The liabilities for compensation deferred under the plan are recorded at fair value in each reporting period. Changes in the fair value of the liabilities are included in operating expense on the Consolidated Statements of Operations. The Company manages the risk of changes in the fair value of the liabilities by electing to match the liabilities with investments in corporate-owned life insurance policies, mutual funds and money market funds that offset a substantial portion of the exposure. The investments are recorded at the cash surrender value of the corporate-owned life insurance policies, and at the fair value of the mutual funds and money market funds, which are classified as trading securities. Changes in the cash surrender value of the corporate-owned life insurance policies and the fair value of mutual fund and money market fund investments are included in other income, net, on the Consolidated Statements of Operations. The following table summarizes the deferred compensation plan balances on the Consolidated Balance Sheets (in thousands): December 31, 2020 2019 Deferred compensation plan asset components: Cash surrender value of corporate-owned life insurance policies $ 19,222 $ 16,883 Fair value of mutual funds and money market funds 26,924 21,975 Total $ 46,146 $ 38,858 Deferred compensation plan assets reported in: Other long-term assets $ 46,146 $ 38,858 Deferred compensation plan liabilities reported in: Accrued compensation and related benefits (short-term) $ 155 $ 425 Other long-term liabilities 48,280 39,665 Total $ 48,435 $ 40,090 Revenue Recognition The Company recognizes revenue when it transfers control of promised goods or services to its customers in an amount that reflects the consideration to which it expects to be entitled to in exchange for those goods or services. See Note 2 Research and Development Costs incurred in research and development are expensed as incurred. Warranty Reserve The Company generally provides one two no not Leases The Company determines if an arrangement is a lease at inception. Lease terms may not The Company does not 12 For lease arrangements where the Company is the lessor, the Company recognizes lease income from operating leases on a straight-line basis over the lease term. Stock-Based Compensation The Company measures the cost of employee services received in exchange for an award of equity instruments based on the grant-date fair value of the award. The fair value of RSUs with only service conditions is determined based on the grant date stock price. The fair value of all other awards is determined based on the following valuation methods: Type of Awards Valuation Method RSUs with performance conditions Black-Scholes model RSUs with market conditions Monte Carlo simulation model RSUs with both performance and market conditions Monte Carlo simulation model Shares issued under the ESPP Black-Scholes model Compensation expense related to awards with service conditions is recorded on a straight-line basis over the requisite service period. Compensation expense related to awards subject to performance or market conditions is recognized over the requisite service period for each separately vesting tranche. For awards with only market conditions, compensation expense is not not not The Company accounts for forfeitures of equity awards when they occur. Accounting for Income Taxes The Company recognizes federal, state and foreign current tax liabilities or assets based on its estimate of taxes payable or refundable in the current fiscal year by tax jurisdiction. The Company also recognizes federal, state and foreign deferred tax assets or liabilities for its estimate of future tax effects attributable to temporary differences and carryforwards. The Company records a valuation allowance to reduce any deferred tax assets by the amount of any tax benefits that, based on available evidence and judgment, are not The Company’s calculation of current and deferred tax assets and liabilities is based on certain estimates and judgments and involves dealing with uncertainties in the application of complex tax laws. The Company’s estimates of current and deferred tax assets and liabilities may 50% may Litigation and Contingencies The Company is a party to actions and proceedings in the ordinary course of business, including potential litigation regarding its stockholders and its intellectual property, challenges to the enforceability or validity of its intellectual property, claims that the Company’s products infringe on the intellectual property rights of others, and employment matters. The pending proceedings involve complex questions of fact and law and will require the expenditure of significant funds and the diversion of other resources to prosecute and defend. In addition, from time to time, the Company becomes aware that it is subject to other contingent liabilities. When this occurs, the Company will evaluate the appropriate accounting for the potential contingent liabilities to determine whether a contingent liability should be recorded. In making this determination, management may, may not Litigation expense recorded on the Consolidated Statements of Operations includes primarily patent infringement litigation and other business matters. The Company records litigation costs in the period in which they are incurred. Proceeds resulting from settlement of litigation or favorable judgments are recorded as a reduction against litigation expense. Net Income per Share Basic net income per share is computed by dividing net income by the weighted-average number of common shares outstanding for the period. Diluted net income per share reflects the potential dilution that would occur if outstanding securities or other contracts to issue common stock were exercised or converted into common shares, and calculated using the treasury stock method. Contingently issuable shares, including equity awards with performance conditions or market conditions, are considered outstanding common shares and included in the basic net income per share as of the date that all necessary conditions to earn the awards have been satisfied. Prior to the end of the contingency period, the number of contingently issuable shares included in the diluted net income per share is based on the number of shares, if any, that would be issuable under the terms of the arrangement at the end of the reporting period. The Company’s RSUs contain forfeitable rights to receive cash dividend equivalents, which are accumulated and paid to the employees when the underlying RSUs vest. Dividend equivalents accumulated on the underlying RSUs are forfeited if the employees do not not not Comprehensive Income Comprehensive income represents the change in the Company’s net assets during the period from non-owner sources. Accumulated other comprehensive income (loss) presented on the Consolidated Balance Sheets primarily consists of unrealized gains or losses related to available-for-sale investments and foreign currency translation adjustments. Recently Adopted Accounting Pronouncements In August 2018 , No. 2018 - 13, Fair Value Measurement (Topic 820 ): Disclosure Framework — Changes to the Disclosure Requirements for Fair Value Measurement, 3 first 2020 not In January 2017 , No. 2017 - 04 , Intangibles – Goodwill and Other (Topic 350 ): Simplifying the Test for Goodwill Impairment, two not first 2020 not In June 2016 , No. 2016 - 13 , Financial Instruments – Credit Losses (Topic 326 ): Measurement of Credit Losses on Financial Instruments, first 2020 , not Recent Accounting Pronouncement Not Yet Adopted as of December 31, 2020 In December 2019, No. 2019 - 12, Income Taxes (Topic 740 ): Simplifying the Accounting for Income Taxes, December 15, 2020 . not Prior Period Reclassifications Certain amounts in prior periods have been reclassified to conform with current period presentation: ● Long-term investments, which were previously presented separately on the Consolidated Balance Sheets, are now reported within other long-term assets. ● Gains and losses on the disposal and sale of property and equipment, which were previously presented separately under operating activities on the Consolidated Statements of Cash Flows, are now reported within the “other” line item under operating activities. ● Accrued purchases of property and equipment, which were previously reported within the "other" line item under other accrued liabilities in Note 5,

Note 2 - Revenue Recognition

Note 2 - Revenue Recognition	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Revenue from Contract with Customer [Text Block]	2. Revenue from Product Sales The Company generates revenue primarily from product sales, which include assembled and tested ICs, as well as dies in wafer form. These product sales accounted for 97%, 99% and 98% of the Company’s total revenue for the years ended December 31, 2020, 2019 2018 , third not 16 The Company sells its products primarily through third December 31, 2020, 2019 2018 , not The Company recognizes revenue when it satisfies a performance obligation by transferring control of the promised goods or services to its customers, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods or services. The Company excludes taxes assessed by government authorities, such as sales taxes, from revenue. Product sales consist of a single performance obligation that the Company satisfies at a point in time. The Company recognizes product revenue from distributors and direct end customers when the following events have occurred: (a) the Company has transferred physical possession of the products, (b) the Company has a present right to payment, (c) the customer has legal title to the products, and (d) the customer bears significant risks and rewards of ownership of the products. In accordance with the shipping terms specified in the contracts, these criteria are generally met when the products are shipped from the Company’s facilities (such as the “Ex Works” shipping term) or delivered to the customers’ locations (such as the “Delivered Duty Paid” shipping term). Under certain consignment agreements, revenue is not not Variable Consideration not Certain distributors have limited stock rotation rights that permit the return of a small percentage of the previous six Contract Balances Accounts Receivable: The Company records a receivable when it has an unconditional right to receive consideration after the performance obligations are satisfied. As of December 31, 2020 2019 , 30 90 not December 31, 2020 , not December 31, 2019 , not Contract Liabilities: For certain customers located in Asia, the Company requires cash payments two December 31, 2020 2019 , December 31, 2020 December 31, 2020 , December 31, 2019 . Practical Expedients The Company has elected the practical expedient to expense sales commissions as incurred because the amortization period would have been one The Company’s standard payment terms generally require customers to pay 30 to 90 days after the Company satisfies the performance obligations. For those customers who are required to pay in advance, the Company satisfies the performance obligations generally within a quarter. The Company has elected not The Company’s unsatisfied performance obligations primarily include products held in consignment arrangements and customer purchase orders for products that the Company has not one not

Note 3 - Cash, Cash Equivalents

Note 3 - Cash, Cash Equivalents, Investments and Restricted Cash	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Financial Instruments Disclosure [Text Block]	3. CASH, CASH EQUIVALENTS, INVESTMENTS AND RESTRICTED CASH The following is a summary of the Company’s cash, cash equivalents and debt investments (in thousands): December 31, 2020 2019 Cash $ 300,609 $ 144,860 Money market funds 34,335 28,100 Corporate debt securities 249,671 260,950 Commercial paper 2,999 1,994 U.S. treasuries and government agency bonds 7,499 19,493 Auction-rate securities backed by student-loan notes 2,861 3,138 Total $ 597,974 $ 458,535 December 31, 2020 2019 Reported as: Cash and cash equivalents $ 334,944 $ 172,960 Short-term investments 260,169 282,437 Investment within other long-term assets 2,861 3,138 Total $ 597,974 $ 458,535 The following table summarizes the contractual maturities of the short-term and long-term available-for-sale investments as of December 31, 2020 ( Amortized Cost Fair Value Due in less than 1 year $ 97,773 $ 98,036 Due in 1 - 5 years 160,316 162,133 Due in greater than 5 years 3,020 2,861 Total $ 261,109 $ 263,030 December 31, 2020, not December 31, 2019 2018. not The following tables summarize the unrealized gain and loss positions related to the available-for sale investments (in thousands): December 31, 2020 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Money market funds $ 34,335 $ - $ - $ 34,335 Corporate debt securities 247,591 2,177 (97 ) 249,671 Commercial paper 2,999 - - 2,999 U.S. treasuries and government agency bonds 7,499 2 (2 ) 7,499 Auction-rate securities backed by student-loan notes 3,020 - (159 ) 2,861 Total $ 295,444 $ 2,179 $ (258 ) $ 297,365 December 31, 2019 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Money market funds $ 28,100 $ - $ - $ 28,100 Corporate debt securities 260,645 383 (78 ) 260,950 Commercial paper 1,994 - - 1,994 U.S. treasuries and government agency bonds 19,487 7 (1 ) 19,493 Auction-rate securities backed by student-loan notes 3,320 - (182 ) 3,138 Total $ 313,546 $ 390 $ (261 ) $ 313,675 12 12 December 31, 2020 Less than 12 Months Greater than 12 Months Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Corporate debt securities $ 59,144 $ (97 ) $ - $ - $ 59,144 $ (97 ) U.S. treasuries and government agency bonds 5,998 (2 ) - - 5,998 (2 ) Auction-rate securities backed by student-loan notes - - 2,861 (159 ) 2,861 (159 ) Total $ 65,142 $ (99 ) $ 2,861 $ (159 ) $ 68,003 $ (258 ) December 31, 2019 Less than 12 Months Greater than 12 Months Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Corporate debt securities $ 82,126 $ (63 ) $ 11,136 $ (15 ) $ 93,262 $ (78 ) U.S. treasuries and government agency bonds 993 (1 ) - - 993 (1 ) Auction-rate securities backed by student-loan notes - - 3,138 (182 ) 3,138 (182 ) Total $ 83,119 $ (64 ) $ 14,274 $ (197 ) $ 97,393 $ (261 ) An impairment exists when the fair value of an investment is less than its amortized cost basis. As of December 31, 2020 , not December 31, 2019 , not one not The Company’s auction-rate securities are backed by pools of student loans supported by guarantees by the U.S. Department of Education. The underlying maturities of these securities are up to 25 not not not Non-Marketable Equity Investment In November 2020, December 31, 2020, not December 31, 2020. Restricted Cash The following table provides a reconciliation of cash, cash equivalents and restricted cash reported on the Consolidated Balance Sheets to the amounts reported on the Consolidated Statements of Cash Flows (in thousands): December 31, 2020 2019 Cash and cash equivalents $ 334,944 $ 172,960 Restricted cash included in other long-term assets 127 116 Total cash, cash equivalents and restricted cash reported on the Consolidated Statements of Cash Flows $ 335,071 $ 173,076 As of December 31, 2020 2019,

Note 4 - Fair Value Measurement

Note 4 - Fair Value Measurements	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Fair Value Disclosures [Text Block]	4. The following table details the fair value of the financial assets measured on a recurring basis (in thousands): December 31, 2020 Total Level 1 Level 2 Level 3 Money market funds $ 34,335 $ 34,335 $ - $ - Corporate debt securities 249,671 - 249,671 - Commercial paper 2,999 - 2,999 - U.S. treasuries and government agency bonds 7,499 - 7,499 - Auction-rate securities backed by student-loan notes 2,861 - - 2,861 Mutual funds and money market funds under deferred compensation plan 26,924 26,924 - - Total $ 324,289 $ 61,259 $ 260,169 $ 2,861 December 31, 2019 Total Level 1 Level 2 Level 3 Money market funds $ 28,100 $ 28,100 $ - $ - Corporate debt securities 260,950 - 260,950 - Commercial paper 1,994 - 1,994 - U.S. treasuries and government agency bonds 19,493 - 19,493 - Auction-rate securities backed by student-loan notes 3,138 - - 3,138 Mutual funds and money market funds under deferred compensation plan 21,975 21,975 - - Total $ 335,650 $ 50,075 $ 282,437 $ 3,138 ● Level 1 — ● Level 2 — may third ● Level 3 — The Company’s level 3 Balance at January 1, 2019 $ 3,241 Change in unrealized gain included in other comprehensive income 147 Sale and settlement at par (250 ) Balance at December 31, 2019 3,138 Change in unrealized gain included in other comprehensive income 23 Sale and settlement at par (300 ) Balance at December 31, 2020 $ 2,861 The Company determined the fair value of the auction-rate securities using a discounted cash flow model with the following assumptions: December 31, 2020 (1) 2019 Time-to-liquidity (in years) 2 - 3 (2.5) 2 - 3 Discount rate 3.5% - 7.9% (5.6%) 4.0% - 8.3% ( 1 The parenthetical value represents the weighted average assumption, which was calculated based on the relative fair value of the securities. The fair value measurement involves the analysis of valuation techniques and evaluation of unobservable inputs commonly used by market participants to price similar instruments. Outputs from the valuation process are assessed against various market sources when they are available, including marketplace quotes, recent trades of similar illiquid securities and independent pricing services. The valuation of the auction-rate securities is subject to significant management judgment regarding projected future cash flows, which will depend on many factors, including the quality of the underlying collateral, estimated time to liquidity including potential to be called or restructured, underlying final maturity, and market conditions, among others. Changes in any of the unobservable inputs used in the fair value measurement of auction-rate securities in isolation would result in a lower or higher fair value measurement. For example, an increase in the time-to-liquidity assumption or estimated discount rate would result in a lower fair value measurement.

Note 5 - Balance Sheet Componen

Note 5 - Balance Sheet Components	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Supplemental Balance Sheet Disclosures [Text Block]	5. Inventories Inventories consist of the following (in thousands): December 31, 2020 2019 Raw materials $ 25,503 $ 22,872 Work in process 77,100 42,681 Finished goods 54,459 61,947 Total $ 157,062 $ 127,500 Other Current Assets Other current assets consist of the following (in thousands): December 31, 2020 2019 RSU tax withholding proceeds receivable $ 12,504 $ 6,106 Prepaid expense 5,032 7,991 Accrued interest receivable 1,914 2,490 Assets for product returns 1,684 1,585 Other 1,846 1,433 Total $ 22,980 $ 19,605 Property and Equipment, Net Property and equipment, net, consist of the following (in thousands): December 31, 2020 2019 Land $ 35,432 $ 35,040 Production equipment and software 163,317 134,292 Buildings and improvements 142,869 131,057 Transportation equipment 18,396 16,510 Leasehold improvements 8,705 6,583 Furniture and fixtures 6,383 4,660 Construction in progress 49,575 19,104 Property and equipment, gross 424,677 347,246 Less: accumulated depreciation and amortization (143,149 ) (118,931 ) Total $ 281,528 $ 228,315 Depreciation and amortization expense on property and equipment was $18.9 million, $14.5 million and $11.4 million for the years ended December 31, 2020, 2019 2018, Other Long-Term Assets Other long-term assets consist of the following (in thousands): December 31, 2020 2019 Deferred compensation plan assets $ 46,146 $ 38,858 Operating lease ROU assets 3,719 2,863 Prepaid expense 2,340 2,687 Debt investment 2,861 3,138 Equity investment in a privately held company 3,400 - Other 1,372 1,544 Total $ 59,838 $ 49,090 Other Accrued Liabilities Other accrued liabilities consist of the following (in thousands): December 31, 2020 2019 Dividends and dividend equivalents $ 26,435 $ 21,747 Stock rotation and sales returns 6,005 5,530 Accrued purchases of property and equipment 5,841 4,678 Income tax payable 3,755 2,435 Customer prepayments 7,238 3,412 Commissions 1,107 1,425 Operating lease liabilities 1,406 1,254 Warranty 6,895 1,139 Other 4,278 3,170 Total $ 62,960 $ 44,790 Other Long-Term Liabilities Other long-term liabilities consist of the following (in thousands): December 31, 2020 2019 Deferred compensation plan liabilities $ 48,280 $ 39,665 Dividend equivalents 7,871 6,265 Operating lease liabilities 1,693 1,103 Other 29 30 Total $ 57,873 $ 47,063

Note 6 - Real Estate Transactio

Note 6 - Real Estate Transaction	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Real Estate Transaction [Text Block]	6. In March 2019, The purchase price allocation was as follows (in thousands): Building $ 30,078 Land 22,254 In-place leases 981 Total $ 53,313 The fair value of the building was determined based on the income approach, which considered the discounted cash flows and direct capitalization analysis, and the sales comparison approach. The fair value of land was determined based on the sales comparison approach. The fair value of the in-place leases was determined primarily based on the analysis of the economic benefits of certain cost savings attributable to the leases. The building is depreciated over a useful life of 40 years and the in-place leases are amortized over the average remaining lease terms of 3.5 years.

Note 7 - Leases

Note 7 - Leases	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Leases Disclosure [Text Block]	7. Lessee The Company has operating leases primarily for administrative and sales and marketing offices, manufacturing operations and research and development facilities, employee housing units and certain equipment. These leases have remaining lease terms from less than a year to five two not As of December 31, 2020 2019 , December 31, 2020 2019 , Year Ended December 31, 2020 2019 Lease costs: Operating lease costs $ 1,488 $ 1,509 Other 300 465 Total lease costs $ 1,788 $ 1,974 Year Ended December 31, 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 1,526 $ 1,364 ROU assets obtained in exchange for new operating lease liabilities (1) $ 2,181 $ 3,667 December 31, 2020 2019 Weighted-average remaining lease term (in years) 2.7 2.1 Weighted-average discount rate 2.7 % 3.7 % ( 1 For the year ended December 31, 2019 , January 1, 2019, No. 2016 02, Leases (Topic 842 As of December 31, 2020, 2021 $ 1,491 2022 993 2023 405 2024 199 2025 139 Total remaining lease payments 3,227 Less: imputed interest (128 ) Total lease liabilities $ 3,099 Reported as: Current liabilities $ 1,406 Long-term liabilities $ 1,693 As of December 31, 2020, not 2021 one four Lessor The Company owns certain office buildings and leases a portion of these properties to third two four five For the years ended December 31, 2020 2019 , December 31, 2020 , 2021 $ 2,153 2022 2,073 2023 1,400 2024 553 2025 59 Total $ 6,238

Note 8 - Stock-based Compensati

Note 8 - Stock-based Compensation	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Share-based Payment Arrangement [Text Block]	8. 2014 In April 2013 , 2014 “ 2014 June 2013 . October 2014 , 2014 2014 November 13, 2014 April 2020 , 2014 2014 June 2020 . 2014 June 11, 2020 2014 June 11, 2030 . December 31, 2020 , 2014 Stock-Based Compensation Expense The Company recognized stock-based compensation expense as follows (in thousands): Year Ended December 31, 2020 2019 2018 Cost of revenue $ 2,592 $ 2,409 $ 1,888 Research and development 20,033 19,584 15,990 Selling, general and administrative 62,926 56,706 42,729 Total stock-based compensation expense $ 85,551 $ 78,699 $ 60,607 Tax benefit related to stock-based compensation (1) $ 1,855 $ 2,754 $ 4,383 ______________ 1 RSUs The Company’s RSUs include time-based RSUs, RSUs with performance conditions (“PSUs”), RSUs with market conditions (“MSUs”), and RSUs with both market and performance conditions (“MPSUs”). Vesting of awards with performance conditions or market conditions is subject to the achievement of pre-determined performance goals and the approval of such achievement by the Compensation Committee of the Board of Directors (the “Compensation Committee”). All awards include service conditions which require continued employment with the Company. A summary of RSU activity is presented in the table below (in thousands, except per-share amounts): Time-Based RSUs PSUs and MPSUs MSUs Total Number of Shares Weighted- Average Grant Date Fair Value Per Share Number of Shares Weighted- Average Grant Date Fair Value Per Share Number of Shares Weighted- Average Grant Date Fair Value Per Share Number of Shares Weighted- Average Grant Date Fair Value Per Share Outstanding at January 1, 2018 258 $ 66.30 2,266 $ 48.59 1,620 $ 23.57 4,144 $ 39.91 Granted 133 $ 114.36 630 (1) $ 85.06 600 $ 68.48 1,363 $ 80.62 Vested (136 ) $ 60.23 (717 ) $ 41.08 - $ - (853 ) $ 44.13 Forfeited (15 ) $ 82.20 (5 ) $ 63.16 (1 ) $ 68.48 (21 ) $ 76.92 Outstanding at December 31, 2018 240 $ 95.38 2,174 $ 61.61 2,219 $ 35.69 4,633 $ 50.94 Granted 52 $ 141.32 512 (1) $ 99.88 - $ - 564 $ 103.68 Vested (103 ) $ 81.53 (656 ) $ 53.72 (324 ) $ 23.57 (1,083 ) $ 47.34 Forfeited (9 ) $ 117.31 (43 ) $ 42.72 (9 ) $ 68.48 (61 ) $ 57.01 Outstanding at December 31, 2019 180 $ 115.45 1,987 $ 74.50 1,886 $ 37.63 4,053 $ 59.16 Granted 76 $ 189.28 627 (1) $ 173.40 - $ - 703 $ 175.12 Vested (86 ) $ 110.67 (1,213 ) $ 59.03 (324 ) $ 23.57 (1,623 ) $ 54.70 Forfeited (9 ) $ 138.34 (11 ) $ 84.48 (8 ) $ 68.48 (28 ) $ 96.35 Outstanding at December 31, 2020 161 $ 151.62 1,390 $ 132.60 1,554 $ 40.40 3,105 $ 87.42 ( 1 Amount reflects the number of awards that may The intrinsic value related to vested RSUs was $326.2 million, $138.3 million and $90.0 million for the years ended December 31, 2020, 2019 2018, December 31, 2020, December 31, 2020, Cash proceeds from vested PSUs with a purchase price totaled $18.8 million, $16.6 million and $10.6 million for the years ended December 31, 2020, 2019 2018, Time-Based RSUs For the years ended December 31, 2020, 2019 2018, four one PSUs and MPSUs 2020 In February 2020 , two 2020 2021 two “ 2020 2020 2020 first 2022 2020 two 2020 In February 2020 , 2021 two 2020 2021 two “2020 2020 2020 first 2022 2020 two 2020 The 2020 2020 $30 20 $30 second 2020. 2020 2020 2020 MPSUs: July 2020 , “2020 2020 five July 20, 2023 , one December 31, 2021 . December 31, 2020, five 2020 July 20, 2023 2020 July 20, 2024 . one 2020 The Company determined the grant date fair value of the 2020 2019 In February 2019, two 2019 2020 two “2019 2019 2019 first 2021. 2019 two 2019 The 2019 not not 2019 In October 2018, 2020 two 2019 2020 two “2019 2019 2019 first 2021. 2019 two 2019 The 2019 not not 2019 2018 In February 2018, two 2018 2019 two “2018 2018 2018 first 2020. 2018 two 2018 In February 2018, 2019 two 2018 2019 two “2018 2018 2018 first 2020. 2018 two 2018 The 2018 2018 not not 2018 2018 2015 In December 2015, “2015 2015 2015 four December 31, 2019. first five January 1, 2016 December 31, 2019. The second, third fourth five second January 1, 2017 December 31, 2019. five third January 1, 2018 December 31, 2019. five fourth January 1, 2019 December 31, 2019. In addition, each of the second, third fourth one six 1. Successful implementation of full digital solutions for certain power products. 2. Successful implementation, and adoption by a key customer, of an integrated, software-based field-oriented control with sensors to motor drivers. 3. Successful implementation of certain advanced power analog processes. 4. Successful design wins and achievement of a specific level of revenue with a global networking customer. 5. Achievement of a specific level of revenue with a global electronics manufacturer. 6. Achievement of a specific level of market share with certain core power products. The following table summarizes the achievement of the market and performance conditions: Tranche Market Conditions Performance Conditions One All stock price targets were achieved as of September 30, 2017. Not Two All stock price targets were achieved as of December 31, 2017. Operating metric #1 December 31, 2018. Three All stock price targets were achieved as of September 30, 2018. Operating metric #2 December 31, 2018. Four All stock price targets were achieved as of March 31, 2019. Operating metric #3 September 30, 2019. A total of 0.6 million shares were awarded to the employees. The 2015 January 1, 2020, two The Company determined the grant date fair value of the 2015 2015 first second third fourth MSUs 2018 In October 2018, “2018 2018 five October 26, 2018 December 31, 2023. December 31, 2019, 2018 January 1, 2024, two 2018 The Company determined the grant date fair value of the 2018 2013 In December 2013, “2013 2013 five January 1, 2014 December 31, 2018. December 31, 2015, 2013 January 1, 2019 December 31, 2023. 2013 The Company determined the grant date fair value of the 2013 not ESPP Under the ESPP, eligible employees may may not six one million first December 31, 2020, November 2024. For the years ended December 31, 2020, 2019 2018, December 31, 2020, 2019 2018, December 31, 2020, first 2021. Year Ended December 31, 2020 2019 2018 Expected term (in years) 0.5 0.5 0.5 Expected volatility 48.9 % 37.0 % 29.5 % Risk-free interest rate 0.8 % 2.2 % 2.0 % Dividend yield 0.9 % 1.1 % 1.0 % Cash proceeds from the shares issued under the ESPP were $3.8 million, $3.3 million and $3.0 million for the years ended December 31, 2020, 2019 2018,

Note 9 - Dividends and Dividend

Note 9 - Dividends and Dividend Equivalents	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Dividends And Dividend Equivalents [Text Block]	9. Cash Dividend Program The Company has a dividend program approved by the Board of Directors, pursuant to which the Company intends to pay quarterly cash dividends on its common stock. Based on the Company’s historical practice, stockholders of record as of the last business day of the quarter are entitled to receive the quarterly cash dividends when and if declared by the Board of Directors, which are payable to the stockholders in the following month. The Board of Directors declared the following cash dividends (in thousands, except per-share amounts): Year Ended December 31, 2020 2019 2018 Dividend declared per share $ 2.00 $ 1.60 $ 1.20 Total amount $ 89,832 $ 69,196 $ 50,803 As of December 31, 2020 2019, may The Company anticipates that cash used for future dividend payments will come from its domestic cash, cash generated from ongoing U.S. operations, and cash repatriated from its Bermuda subsidiary. The Company also anticipates that earnings from other foreign subsidiaries will continue to be indefinitely reinvested. Cash Dividend Equivalent Rights The Company's RSUs contain rights to receive cash dividend equivalents, which entitle employees who hold RSUs to the same dividend value per share as holders of common stock. The dividend equivalents are accumulated and paid to the employees when the underlying RSUs vest. Dividend equivalents accumulated on the underlying RSUs are forfeited if the employees do not not December 31, 2020 2019 ,

Note 10 - Other Income, Net

Note 10 - Other Income, Net	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Other Nonoperating Income and Expense [Text Block]	10. OTHER INCOME, NET The components of other income, net, are as follows (in thousands): Year Ended December 31, 2020 2019 2018 Interest income $ 9,327 $ 7,305 $ 6,321 Amortization of premium on available-for-sale securities (2,979 ) (729 ) (1,353 ) Gain (loss) on deferred compensation plan investments 4,592 3,806 (1,022 ) Foreign currency exchange gain (loss) (1,364 ) (310 ) 953 Other 884 486 95 Total $ 10,460 $ 10,558 $ 4,994

Note 11 - Net Income Per Share

Note 11 - Net Income Per Share	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Earnings Per Share [Text Block]	11. The following table sets forth the computation of basic and diluted net income per share (in thousands, except per share amounts): Year Ended December 31, 2020 2019 2018 Numerator: Net income $ 164,375 $ 108,839 $ 105,268 Denominator: Weighted-average outstanding shares - basic 44,840 43,165 42,247 Effect of dilutive securities 2,174 2,598 2,355 Weighted-average outstanding shares - diluted 47,014 45,763 44,602 Net income per share: Basic $ 3.67 $ 2.52 $ 2.49 Diluted $ 3.50 $ 2.38 $ 2.36 Anti-dilutive common stock equivalents were not

Note 12 - Income Taxes

Note 12 - Income Taxes	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Income Tax Disclosure [Text Block]	12. The components of income before income taxes are as follows (in thousands): Year Ended December 31, 2020 2019 2018 United States $ 39,286 $ (4,134 ) $ (13,151 ) Foreign 130,056 117,254 131,633 Income before income taxes $ 169,342 $ 113,120 $ 118,482 The components of the income tax expense are as follows (in thousands): Year Ended December 31, 2020 2019 2018 Current: Federal $ 2,842 $ 1,682 $ 11,023 State (1 ) 8 4 Foreign 3,814 3,105 2,992 Deferred: Federal (1,221 ) (213 ) (797 ) Foreign (467 ) (301 ) (8 ) Income tax expense $ 4,967 $ 4,281 $ 13,214 The effective tax rate differs from the applicable U.S. statutory federal income tax rate as follows: Year Ended December 31, 2020 2019 2018 U.S. statutory federal tax rate 21.0 % 21.0 % 21.0 % Foreign income at lower rates (15.2 ) (20.7 ) (22.0 ) Impact of the 2017 Tax Act: One-time deemed repatriation transition tax - - 0.6 GILTI 11.1 11.0 14.4 Changes in valuation allowance 1.6 2.1 - Stock-based compensation (11.2 ) (1.5 ) (1.1 ) Tax credits, net of reserves (3.8 ) (6.2 ) (1.9 ) State income taxes (1.6 ) (0.7 ) - Other adjustments 1.0 (1.2 ) 0.2 Effective tax rate 2.9 % 3.8 % 11.2 % The components of net deferred tax assets consist of the following (in thousands): December 31, 2020 2019 Deferred tax assets: Tax credits $ 23,501 $ 18,080 Stock-based compensation 2,392 6,237 Deferred compensation 7,895 7,110 Net operating losses 1,150 615 Other expenses not currently deductible 4,617 2,323 Deferred tax assets, gross 39,555 34,365 Valuation allowance (18,190 ) (15,411 ) Deferred tax assets, net of valuation allowance 21,365 18,954 Deferred tax liabilities: Depreciation and amortization (1,600 ) (1,259 ) Undistributed foreign earnings (77 ) (77 ) Other expenses currently deductible (1,132 ) (425 ) Deferred tax liabilities (2,809 ) (1,761 ) Net deferred tax assets $ 18,556 $ 17,193 GILTI: The Company accounts for GILTI as a period cost. Valuation Allowance: The Company periodically evaluates its deferred tax assets, including a determination of whether a valuation allowance is necessary, based upon its ability to utilize the assets using a more likely than not December 31, 2020 2019, not not Undistributed Earnings of Subsidiaries: The Company has analyzed its global working capital and cash requirements, and has determined that it plans to repatriate cash from its Bermuda subsidiary on an ongoing basis to fund its future U.S.-based expenditures and dividends. For the years ended December 31, 2020 2019, For all other foreign subsidiaries, the Company expects to indefinitely reinvest undistributed earnings to fund their operations and research and development. As of December 31, 2020 2019, not Other Income Tax Provision Matters As of December 31, 2020, not December 31, 2020, 2024. As of December 31, 2020, 2040, In the event of a change in ownership, as defined under federal and state tax laws, the Company's net operating loss and tax credit carryforwards could be subject to annual limitations. The annual limitations could result in the expiration of the net operating loss and tax credit carryforwards prior to utilization. At December 31, 2020, December 31, 2019, A reconciliation of the gross unrecognized tax benefits is as follows (in thousands): Balance as of January 1, 2018 $ 16,272 Increase for tax position of prior year 1,474 Increase for tax position of current year 2,957 Decrease due to lapse of statute of limitation (212 ) Balance as of December 31, 2018 20,491 Increase for tax position of prior year 1,589 Increase for tax position of current year 4,663 Decrease due to settlement with tax authorities (560 ) Decrease due to lapse of statute of limitation (776 ) Balance as of December 31, 2019 25,407 Increase for tax position of current year 9,782 Decrease for tax position of prior year (907 ) Decrease due to settlement with tax authorities (560 ) Decrease due to lapse of statute of limitation (223 ) Balance as of December 31, 2020 $ 33,499 The Company recognizes interest and penalties, if any, related to uncertain tax positions in its income tax provision. As of December 31, 2020 2019, Uncertain tax positions relate to the allocation of income and deductions among the Company’s global entities and to the determination of the research and development tax credit. Various events, some of which cannot be predicted, such as clarification of tax law by administrative or judicial means, may twelve not The Company currently has reduced tax rates in its subsidiaries in Chengdu and Hangzhou, China through 2030 2023, In July 2015 , Altera Corp. v. Commissioner December 2015 , June 2016 . June 2019 , July 2019 , November 2019 , February 2020 , June 2020, no Income Tax Examination The Company is subject to examination of its income tax returns by the IRS and other tax authorities. In general, the tax years for 2007

Note 13 - Commitments and Conti

Note 13 - Commitments and Contingencies	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Commitments and Contingencies Disclosure [Text Block]	13. Warranty and Indemnification Provisions The changes in warranty reserves are as follows (in thousands): Year Ended December 31, 2020 2019 2018 Balance at beginning of period $ 1,139 $ 4,564 $ 2,416 Warranty provision for product sales 7,584 891 6,586 Settlements made (843 ) (2,768 ) (1,402 ) Unused warranty provision (985 ) (1,548 ) (3,036 ) Balance at end of period $ 6,895 $ 1,139 $ 4,564 The Company provides indemnification agreements to certain direct or indirect customers. The Company agrees to reimburse these parties for any damages, costs and expenses incurred by them as a result of legal actions taken against them by third It is not no no not Purchase Commitments The Company has outstanding purchase commitments with its suppliers and other parties that require the future purchases of goods or services, which primarily consist of wafer and other inventory purchases, assembly and other manufacturing services, construction or purchases of property and equipment, and license arrangements. As of December 31, 2020 , Litigation The Company is a party to actions and proceedings in the ordinary course of business, including potential litigation initiated by its stockholders, challenges to the enforceability or validity of its intellectual property, claims that the Company’s products infringe on the intellectual property rights of others, and employment matters. These proceedings often involve complex questions of fact and law and may December 31, 2020 , no

Note 14 - Employee 401(k) Plan

Note 14 - Employee 401(k) Plan	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Retirement Benefits [Text Block]	14. 401 The Company sponsors a 401 may not not December 31, 2020, 2019 2018.

Note 15 - Significant Customers

Note 15 - Significant Customers	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Concentration Risk Disclosure [Text Block]	15. The Company sells its products primarily through third 10% Year Ended December 31, Customer 2020 2019 2018 Distributor A 24 % 23 % 22 % Distributor B 11 % * 10 % * Represents less than 10%. The Company’s agreements with these third may may not The following table summarizes those customers with accounts receivable equal to 10% December 31, 2020 2019 Distributor A 24 % 24 % Distributor B 21 % 11 % Value-added reseller A 13 % 13 % Direct customer A 10 % * * Represents less than 10%.

Note 16 - Segment and Geographi

Note 16 - Segment and Geographic Information	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Segment Reporting Disclosure [Text Block]	16. The Company operates in one reportable segment that includes the design, development, marketing and sale of high-performance analog solutions for the computing and storage, automotive, industrial, communications and consumer markets. The Company’s chief operating decision maker is its Chief Executive Officer, who reviews financial information presented on a consolidated basis for purposes of allocating resources and evaluating financial performance. The Company derives a majority of its revenue from sales to customers located outside North America, with geographic revenue based on the customers’ ship-to locations. The following is a summary of revenue by geographic regions (in thousands): Year Ended December 31, Country or Region 2020 2019 2018 China $ 516,519 $ 382,740 $ 334,726 Taiwan 109,256 73,801 75,307 Europe 56,329 49,467 49,484 South Korea 64,093 43,900 41,238 Southeast Asia 42,403 32,031 36,495 Japan 35,461 27,812 26,853 United States 20,098 17,836 17,621 Other 293 334 658 Total $ 844,452 $ 627,921 $ 582,382 The following is a summary of revenue by major product families (in thousands): Year Ended December 31, Product Family 2020 2019 2018 DC to DC $ 800,478 $ 589,651 $ 537,512 Lighting Control 43,974 38,270 44,870 Total $ 844,452 $ 627,921 $ 582,382 The following is a summary of long-lived assets by geographic regions (in thousands): December 31, Country 2020 2019 2018 China $ 151,752 $ 113,888 $ 93,096 United States 101,768 94,671 39,054 Taiwan 18,797 17,652 16,972 Other 9,211 2,104 879 Total $ 281,528 $ 228,315 $ 150,001

Note 17 - Accumulated Other Com

Note 17 - Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Comprehensive Income (Loss) Note [Text Block]	17. INCOME ( LOSS ) The following table summarizes the changes in accumulated other comprehensive income (loss) (in thousands): Unrealized Gains (Losses) on Available-for-Sale Securities Foreign Currency Translation Adjustments Total Balance as of January 1, 2019 $ (1,638 ) $ (3,905 ) $ (5,543 ) Other comprehensive income (loss) before reclassifications 1,977 (1,706 ) 271 Amounts reclassified from accumulated other comprehensive loss (1 ) - (1 ) Tax effect (203 ) - (203 ) Net current period other comprehensive income (loss) 1,773 (1,706 ) 67 Balance as of December 31, 2019 135 (5,611 ) (5,476 ) Other comprehensive income before reclassifications 2,878 14,150 17,028 Amounts reclassified from accumulated other comprehensive income (loss) (1,087 ) - (1,087 ) Tax effect (325 ) - (325 ) Net current period other comprehensive income 1,466 14,150 15,616 Balance as of December 31, 2020 $ 1,601 $ 8,539 $ 10,140 The amounts reclassified from accumulated other comprehensive income (loss) were recorded in other income, net, on the Consolidated Statements of Operations.

Note 18 - Subsequent Event

Note 18 - Subsequent Event	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Subsequent Events [Text Block]	18. Cash Dividend Increase In February 2021,

Significant Accounting Policies

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Consolidation, Policy [Policy Text Block]	Basis of Presentation The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. Intercompany accounts and transactions have been eliminated in consolidation.
Use of Estimates, Policy [Policy Text Block]	Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America (“GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, and reported amounts of revenue and expenses during the reporting period. Significant estimates and assumptions used in these consolidated financial statements primarily include those related to revenue recognition, inventory valuation, valuation of share-based awards, contingencies and income tax valuation allowances. Actual results could differ from these estimates and assumptions, and any such differences may The COVID- 19 not December 31, 2020 , As of the date of issuance of these consolidated financial statements, the Company is not .
Concentration Risk, Credit Risk, Policy [Policy Text Block]	Certain Significant Risks and Uncertainties Financial instruments which potentially subject the Company to concentrations of credit risk consist primarily of cash equivalents, short-term and long-term investments and accounts receivable. The Company’s cash equivalents include short-term, highly liquid investments purchased with remaining maturities at the date of purchase of three may The Company does not may The Company participates in the dynamic high technology industry and believes that changes in any of the following areas could have a material adverse effect on its future financial position, results of operations or cash flows: advances and trends in new technologies and industry standards; competitive pressures in the form of new products or price reductions on current products; changes in product mix; changes in the overall demand for products offered by the Company; changes in third
Foreign Currency Transactions and Translations Policy [Policy Text Block]	Foreign Currency In general, the functional currency of the Company’s international subsidiaries is the local currency. The primary subsidiaries are located in China, Taiwan and Europe, which utilize the Renminbi, the New Taiwan Dollar and the Euro as their currencies, respectively. Accordingly, assets and liabilities of the foreign subsidiaries are translated using exchange rates in effect at the end of the period. Revenue and costs are translated using average exchange rates for the period. The resulting translation adjustments are recorded in accumulated other comprehensive income (loss) on the Consolidated Balance Sheets. In addition, the Company incurs foreign currency exchange gain or loss related to certain intercompany transactions between the U.S. and its foreign subsidiaries that are denominated in a currency other than the functional currency. In connection with the settlement and remeasurement of the balances, the Company recorded foreign currency exchange gain (loss) of $(1.4) million, $(0.3) million and $1.0 million for the years ended December 31, 2020, 2019 2018,
Cash and Cash Equivalents, Policy [Policy Text Block]	Cash Equivalents and Debt Investments The Company classifies all highly liquid investments with stated maturities of three may one Cash equivalents are stated at cost, which approximates fair market value. The Company’s short-term and long-term debt investments are classified as available-for-sale securities and are stated at their fair market value, with unrealized gains and losses recorded in accumulated other comprehensive income (loss) on the Consolidated Balance Sheets. Premiums and discounts on debt investments are generally amortized or accreted over the life of the related available-for-sale securities. Interest income is recognized when earned. The cost of investments sold is determined on a specific identification method. Available-for-sale investments are subject to impairment reviews when the fair value is below the amortized cost basis. If the Company determines that the decline in fair value below the amortized cost basis is due to credit-related factors, the impairment is recognized as an allowance on the Consolidated Balance Sheets with a corresponding adjustment to earnings. An impairment that is not not
Equity Securities without Readily Determinable Fair Value [Policy Text Block]	Equity Investments Equity investments in privately held companies without readily determinable fair values are accounted for under the measurement alternative, provided that the Company does not The Company monitors its non-marketable equity investments for impairment indicators, such as negative changes in industry and market conditions, financial performance, business prospects, and other relevant events and factors. If indicators exist for a security and the fair value is below the carrying amount, the Company writes down the security to fair value.
Fair Value of Financial Instruments, Policy [Policy Text Block]	Fair Value of Financial Instruments Fair value is defined as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining the fair value, the Company considers the principal or most advantageous market in which the Company would transact, as well as assumptions that market participants would use when pricing the assets or liabilities. Fair value is estimated by applying the following hierarchy, which prioritizes the inputs used to measure fair value into three ● Level 1 ● Level 2 not ● Level 3
Inventory, Policy [Policy Text Block]	Inventories Inventories are stated at the lower of standard cost (which approximates actual cost determined on a first first may may not
Property, Plant and Equipment, Policy [Policy Text Block]	Property and Equipment Property and equipment are stated at cost. Depreciation commences when an asset is placed in service and available for its intended use. Depreciation is computed using the straight-line method over the estimated useful lives of the assets. Buildings and building improvements have estimated useful lives of 20 to 40 years. Leasehold improvements are amortized over the shorter of the estimated useful lives or the lease period. Production equipment and software have estimated useful lives of three eight three five not
Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]	Impairment of Long-Lived Assets The Company evaluates its long-lived assets other than goodwill for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not not
Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block]	Goodwill Goodwill represents the excess of the fair value of purchase consideration over the fair value of net tangible and identified intangible assets as of the date of acquisition. Goodwill is not The Company tests goodwill for impairment at least annually in the fourth may first not not No
Deferred Compensation Plan, Policy [Policy Text Block]	Deferred Compensation Plan The Company has a non-qualified, unfunded deferred compensation plan, which provides certain key employees, including executive officers, with the ability to defer the receipt of compensation in order to accumulate funds for retirement on a tax deferred basis. The Company does not The liabilities for compensation deferred under the plan are recorded at fair value in each reporting period. Changes in the fair value of the liabilities are included in operating expense on the Consolidated Statements of Operations. The Company manages the risk of changes in the fair value of the liabilities by electing to match the liabilities with investments in corporate-owned life insurance policies, mutual funds and money market funds that offset a substantial portion of the exposure. The investments are recorded at the cash surrender value of the corporate-owned life insurance policies, and at the fair value of the mutual funds and money market funds, which are classified as trading securities. Changes in the cash surrender value of the corporate-owned life insurance policies and the fair value of mutual fund and money market fund investments are included in other income, net, on the Consolidated Statements of Operations. The following table summarizes the deferred compensation plan balances on the Consolidated Balance Sheets (in thousands): December 31, 2020 2019 Deferred compensation plan asset components: Cash surrender value of corporate-owned life insurance policies $ 19,222 $ 16,883 Fair value of mutual funds and money market funds 26,924 21,975 Total $ 46,146 $ 38,858 Deferred compensation plan assets reported in: Other long-term assets $ 46,146 $ 38,858 Deferred compensation plan liabilities reported in: Accrued compensation and related benefits (short-term) $ 155 $ 425 Other long-term liabilities 48,280 39,665 Total $ 48,435 $ 40,090
Revenue from Contract with Customer [Policy Text Block]	Revenue Recognition The Company recognizes revenue when it transfers control of promised goods or services to its customers in an amount that reflects the consideration to which it expects to be entitled to in exchange for those goods or services. See Note 2
Research and Development Expense, Policy [Policy Text Block]	Research and Development Costs incurred in research and development are expensed as incurred.
Standard Product Warranty, Policy [Policy Text Block]	Warranty Reserve The Company generally provides one two no not
Lessee, Leases [Policy Text Block]	Leases The Company determines if an arrangement is a lease at inception. Lease terms may not The Company does not 12 For lease arrangements where the Company is the lessor, the Company recognizes lease income from operating leases on a straight-line basis over the lease term.
Share-based Payment Arrangement [Policy Text Block]	Stock-Based Compensation The Company measures the cost of employee services received in exchange for an award of equity instruments based on the grant-date fair value of the award. The fair value of RSUs with only service conditions is determined based on the grant date stock price. The fair value of all other awards is determined based on the following valuation methods: Type of Awards Valuation Method RSUs with performance conditions Black-Scholes model RSUs with market conditions Monte Carlo simulation model RSUs with both performance and market conditions Monte Carlo simulation model Shares issued under the ESPP Black-Scholes model Compensation expense related to awards with service conditions is recorded on a straight-line basis over the requisite service period. Compensation expense related to awards subject to performance or market conditions is recognized over the requisite service period for each separately vesting tranche. For awards with only market conditions, compensation expense is not not not The Company accounts for forfeitures of equity awards when they occur.
Income Tax, Policy [Policy Text Block]	Accounting for Income Taxes The Company recognizes federal, state and foreign current tax liabilities or assets based on its estimate of taxes payable or refundable in the current fiscal year by tax jurisdiction. The Company also recognizes federal, state and foreign deferred tax assets or liabilities for its estimate of future tax effects attributable to temporary differences and carryforwards. The Company records a valuation allowance to reduce any deferred tax assets by the amount of any tax benefits that, based on available evidence and judgment, are not The Company’s calculation of current and deferred tax assets and liabilities is based on certain estimates and judgments and involves dealing with uncertainties in the application of complex tax laws. The Company’s estimates of current and deferred tax assets and liabilities may 50% may
Litigation and Contingencies, Policy [Policy Text Block]	Litigation and Contingencies The Company is a party to actions and proceedings in the ordinary course of business, including potential litigation regarding its stockholders and its intellectual property, challenges to the enforceability or validity of its intellectual property, claims that the Company’s products infringe on the intellectual property rights of others, and employment matters. The pending proceedings involve complex questions of fact and law and will require the expenditure of significant funds and the diversion of other resources to prosecute and defend. In addition, from time to time, the Company becomes aware that it is subject to other contingent liabilities. When this occurs, the Company will evaluate the appropriate accounting for the potential contingent liabilities to determine whether a contingent liability should be recorded. In making this determination, management may, may not Litigation expense recorded on the Consolidated Statements of Operations includes primarily patent infringement litigation and other business matters. The Company records litigation costs in the period in which they are incurred. Proceeds resulting from settlement of litigation or favorable judgments are recorded as a reduction against litigation expense.
Earnings Per Share, Policy [Policy Text Block]	Net Income per Share Basic net income per share is computed by dividing net income by the weighted-average number of common shares outstanding for the period. Diluted net income per share reflects the potential dilution that would occur if outstanding securities or other contracts to issue common stock were exercised or converted into common shares, and calculated using the treasury stock method. Contingently issuable shares, including equity awards with performance conditions or market conditions, are considered outstanding common shares and included in the basic net income per share as of the date that all necessary conditions to earn the awards have been satisfied. Prior to the end of the contingency period, the number of contingently issuable shares included in the diluted net income per share is based on the number of shares, if any, that would be issuable under the terms of the arrangement at the end of the reporting period. The Company’s RSUs contain forfeitable rights to receive cash dividend equivalents, which are accumulated and paid to the employees when the underlying RSUs vest. Dividend equivalents accumulated on the underlying RSUs are forfeited if the employees do not not not
Comprehensive Income, Policy [Policy Text Block]	Comprehensive Income Comprehensive income represents the change in the Company’s net assets during the period from non-owner sources. Accumulated other comprehensive income (loss) presented on the Consolidated Balance Sheets primarily consists of unrealized gains or losses related to available-for-sale investments and foreign currency translation adjustments.
New Accounting Pronouncements, Policy [Policy Text Block]	Recently Adopted Accounting Pronouncements In August 2018 , No. 2018 - 13, Fair Value Measurement (Topic 820 ): Disclosure Framework — Changes to the Disclosure Requirements for Fair Value Measurement, 3 first 2020 not In January 2017 , No. 2017 - 04 , Intangibles – Goodwill and Other (Topic 350 ): Simplifying the Test for Goodwill Impairment, two not first 2020 not In June 2016 , No. 2016 - 13 , Financial Instruments – Credit Losses (Topic 326 ): Measurement of Credit Losses on Financial Instruments, first 2020 , not Recent Accounting Pronouncement Not Yet Adopted as of December 31, 2020 In December 2019, No. 2019 - 12, Income Taxes (Topic 740 ): Simplifying the Accounting for Income Taxes, December 15, 2020 . not
Reclassification, Comparability Adjustment [Policy Text Block]	Prior Period Reclassifications Certain amounts in prior periods have been reclassified to conform with current period presentation: ● Long-term investments, which were previously presented separately on the Consolidated Balance Sheets, are now reported within other long-term assets. ● Gains and losses on the disposal and sale of property and equipment, which were previously presented separately under operating activities on the Consolidated Statements of Cash Flows, are now reported within the “other” line item under operating activities. ● Accrued purchases of property and equipment, which were previously reported within the "other" line item under other accrued liabilities in Note 5,

Note 1 - Summary of Significa_2

Note 1 - Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Schedule of Deferred Compensation Plan [Table Text Block]	December 31, 2020 2019 Deferred compensation plan asset components: Cash surrender value of corporate-owned life insurance policies $ 19,222 $ 16,883 Fair value of mutual funds and money market funds 26,924 21,975 Total $ 46,146 $ 38,858 Deferred compensation plan assets reported in: Other long-term assets $ 46,146 $ 38,858 Deferred compensation plan liabilities reported in: Accrued compensation and related benefits (short-term) $ 155 $ 425 Other long-term liabilities 48,280 39,665 Total $ 48,435 $ 40,090

Note 3 - Cash, Cash Equivalen_2

Note 3 - Cash, Cash Equivalents, Investments and Restricted Cash (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Fair Value, by Balance Sheet Grouping [Table Text Block]	December 31, 2020 2019 Cash $ 300,609 $ 144,860 Money market funds 34,335 28,100 Corporate debt securities 249,671 260,950 Commercial paper 2,999 1,994 U.S. treasuries and government agency bonds 7,499 19,493 Auction-rate securities backed by student-loan notes 2,861 3,138 Total $ 597,974 $ 458,535 December 31, 2020 2019 Reported as: Cash and cash equivalents $ 334,944 $ 172,960 Short-term investments 260,169 282,437 Investment within other long-term assets 2,861 3,138 Total $ 597,974 $ 458,535
Investments Classified by Contractual Maturity Date [Table Text Block]	Amortized Cost Fair Value Due in less than 1 year $ 97,773 $ 98,036 Due in 1 - 5 years 160,316 162,133 Due in greater than 5 years 3,020 2,861 Total $ 261,109 $ 263,030
Unrealized Gain (Loss) on Investments [Table Text Block]	December 31, 2020 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Money market funds $ 34,335 $ - $ - $ 34,335 Corporate debt securities 247,591 2,177 (97 ) 249,671 Commercial paper 2,999 - - 2,999 U.S. treasuries and government agency bonds 7,499 2 (2 ) 7,499 Auction-rate securities backed by student-loan notes 3,020 - (159 ) 2,861 Total $ 295,444 $ 2,179 $ (258 ) $ 297,365 December 31, 2019 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Money market funds $ 28,100 $ - $ - $ 28,100 Corporate debt securities 260,645 383 (78 ) 260,950 Commercial paper 1,994 - - 1,994 U.S. treasuries and government agency bonds 19,487 7 (1 ) 19,493 Auction-rate securities backed by student-loan notes 3,320 - (182 ) 3,138 Total $ 313,546 $ 390 $ (261 ) $ 313,675
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value [Table Text Block]	December 31, 2020 Less than 12 Months Greater than 12 Months Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Corporate debt securities $ 59,144 $ (97 ) $ - $ - $ 59,144 $ (97 ) U.S. treasuries and government agency bonds 5,998 (2 ) - - 5,998 (2 ) Auction-rate securities backed by student-loan notes - - 2,861 (159 ) 2,861 (159 ) Total $ 65,142 $ (99 ) $ 2,861 $ (159 ) $ 68,003 $ (258 ) December 31, 2019 Less than 12 Months Greater than 12 Months Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Corporate debt securities $ 82,126 $ (63 ) $ 11,136 $ (15 ) $ 93,262 $ (78 ) U.S. treasuries and government agency bonds 993 (1 ) - - 993 (1 ) Auction-rate securities backed by student-loan notes - - 3,138 (182 ) 3,138 (182 ) Total $ 83,119 $ (64 ) $ 14,274 $ (197 ) $ 97,393 $ (261 )
Restrictions on Cash and Cash Equivalents [Table Text Block]	December 31, 2020 2019 Cash and cash equivalents $ 334,944 $ 172,960 Restricted cash included in other long-term assets 127 116 Total cash, cash equivalents and restricted cash reported on the Consolidated Statements of Cash Flows $ 335,071 $ 173,076

Note 4 - Fair Value Measureme_2

Note 4 - Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]	December 31, 2020 Total Level 1 Level 2 Level 3 Money market funds $ 34,335 $ 34,335 $ - $ - Corporate debt securities 249,671 - 249,671 - Commercial paper 2,999 - 2,999 - U.S. treasuries and government agency bonds 7,499 - 7,499 - Auction-rate securities backed by student-loan notes 2,861 - - 2,861 Mutual funds and money market funds under deferred compensation plan 26,924 26,924 - - Total $ 324,289 $ 61,259 $ 260,169 $ 2,861 December 31, 2019 Total Level 1 Level 2 Level 3 Money market funds $ 28,100 $ 28,100 $ - $ - Corporate debt securities 260,950 - 260,950 - Commercial paper 1,994 - 1,994 - U.S. treasuries and government agency bonds 19,493 - 19,493 - Auction-rate securities backed by student-loan notes 3,138 - - 3,138 Mutual funds and money market funds under deferred compensation plan 21,975 21,975 - - Total $ 335,650 $ 50,075 $ 282,437 $ 3,138
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]	Balance at January 1, 2019 $ 3,241 Change in unrealized gain included in other comprehensive income 147 Sale and settlement at par (250 ) Balance at December 31, 2019 3,138 Change in unrealized gain included in other comprehensive income 23 Sale and settlement at par (300 ) Balance at December 31, 2020 $ 2,861
Fair Value Measurement Inputs and Valuation Techniques [Table Text Block]	December 31, 2020 (1) 2019 Time-to-liquidity (in years) 2 - 3 (2.5) 2 - 3 Discount rate 3.5% - 7.9% (5.6%) 4.0% - 8.3%

Note 5 - Balance Sheet Compon_2

Note 5 - Balance Sheet Components (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Schedule of Inventory, Current [Table Text Block]	December 31, 2020 2019 Raw materials $ 25,503 $ 22,872 Work in process 77,100 42,681 Finished goods 54,459 61,947 Total $ 157,062 $ 127,500
Schedule of Other Current Assets [Table Text Block]	December 31, 2020 2019 RSU tax withholding proceeds receivable $ 12,504 $ 6,106 Prepaid expense 5,032 7,991 Accrued interest receivable 1,914 2,490 Assets for product returns 1,684 1,585 Other 1,846 1,433 Total $ 22,980 $ 19,605
Property, Plant and Equipment [Table Text Block]	December 31, 2020 2019 Land $ 35,432 $ 35,040 Production equipment and software 163,317 134,292 Buildings and improvements 142,869 131,057 Transportation equipment 18,396 16,510 Leasehold improvements 8,705 6,583 Furniture and fixtures 6,383 4,660 Construction in progress 49,575 19,104 Property and equipment, gross 424,677 347,246 Less: accumulated depreciation and amortization (143,149 ) (118,931 ) Total $ 281,528 $ 228,315
Schedule of Other Assets, Noncurrent [Table Text Block]	December 31, 2020 2019 Deferred compensation plan assets $ 46,146 $ 38,858 Operating lease ROU assets 3,719 2,863 Prepaid expense 2,340 2,687 Debt investment 2,861 3,138 Equity investment in a privately held company 3,400 - Other 1,372 1,544 Total $ 59,838 $ 49,090
Schedule of Accrued Liabilities [Table Text Block]	December 31, 2020 2019 Dividends and dividend equivalents $ 26,435 $ 21,747 Stock rotation and sales returns 6,005 5,530 Accrued purchases of property and equipment 5,841 4,678 Income tax payable 3,755 2,435 Customer prepayments 7,238 3,412 Commissions 1,107 1,425 Operating lease liabilities 1,406 1,254 Warranty 6,895 1,139 Other 4,278 3,170 Total $ 62,960 $ 44,790
Other Noncurrent Liabilities [Table Text Block]	December 31, 2020 2019 Deferred compensation plan liabilities $ 48,280 $ 39,665 Dividend equivalents 7,871 6,265 Operating lease liabilities 1,693 1,103 Other 29 30 Total $ 57,873 $ 47,063

Note 6 - Real Estate Transact_2

Note 6 - Real Estate Transaction (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Asset Acquisition, Allocation of Consideration [Table Text Block]	Building $ 30,078 Land 22,254 In-place leases 981 Total $ 53,313

Note 7 - Leases (Tables)

Note 7 - Leases (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Lease, Cost [Table Text Block]	Year Ended December 31, 2020 2019 Lease costs: Operating lease costs $ 1,488 $ 1,509 Other 300 465 Total lease costs $ 1,788 $ 1,974 Year Ended December 31, 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 1,526 $ 1,364 ROU assets obtained in exchange for new operating lease liabilities (1) $ 2,181 $ 3,667 December 31, 2020 2019 Weighted-average remaining lease term (in years) 2.7 2.1 Weighted-average discount rate 2.7 % 3.7 %
Lessee, Operating Lease, Liability, Maturity [Table Text Block]	2021 $ 1,491 2022 993 2023 405 2024 199 2025 139 Total remaining lease payments 3,227 Less: imputed interest (128 ) Total lease liabilities $ 3,099 Reported as: Current liabilities $ 1,406 Long-term liabilities $ 1,693
Lessor, Operating Lease, Payment to be Received, Fiscal Year Maturity [Table Text Block]	2021 $ 2,153 2022 2,073 2023 1,400 2024 553 2025 59 Total $ 6,238

Note 8 - Stock-based Compensa_2

Note 8 - Stock-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Share-based Payment Arrangement, Cost by Plan [Table Text Block]	Year Ended December 31, 2020 2019 2018 Cost of revenue $ 2,592 $ 2,409 $ 1,888 Research and development 20,033 19,584 15,990 Selling, general and administrative 62,926 56,706 42,729 Total stock-based compensation expense $ 85,551 $ 78,699 $ 60,607 Tax benefit related to stock-based compensation (1) $ 1,855 $ 2,754 $ 4,383
Share-based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity [Table Text Block]	Time-Based RSUs PSUs and MPSUs MSUs Total Number of Shares Weighted- Average Grant Date Fair Value Per Share Number of Shares Weighted- Average Grant Date Fair Value Per Share Number of Shares Weighted- Average Grant Date Fair Value Per Share Number of Shares Weighted- Average Grant Date Fair Value Per Share Outstanding at January 1, 2018 258 $ 66.30 2,266 $ 48.59 1,620 $ 23.57 4,144 $ 39.91 Granted 133 $ 114.36 630 (1) $ 85.06 600 $ 68.48 1,363 $ 80.62 Vested (136 ) $ 60.23 (717 ) $ 41.08 - $ - (853 ) $ 44.13 Forfeited (15 ) $ 82.20 (5 ) $ 63.16 (1 ) $ 68.48 (21 ) $ 76.92 Outstanding at December 31, 2018 240 $ 95.38 2,174 $ 61.61 2,219 $ 35.69 4,633 $ 50.94 Granted 52 $ 141.32 512 (1) $ 99.88 - $ - 564 $ 103.68 Vested (103 ) $ 81.53 (656 ) $ 53.72 (324 ) $ 23.57 (1,083 ) $ 47.34 Forfeited (9 ) $ 117.31 (43 ) $ 42.72 (9 ) $ 68.48 (61 ) $ 57.01 Outstanding at December 31, 2019 180 $ 115.45 1,987 $ 74.50 1,886 $ 37.63 4,053 $ 59.16 Granted 76 $ 189.28 627 (1) $ 173.40 - $ - 703 $ 175.12 Vested (86 ) $ 110.67 (1,213 ) $ 59.03 (324 ) $ 23.57 (1,623 ) $ 54.70 Forfeited (9 ) $ 138.34 (11 ) $ 84.48 (8 ) $ 68.48 (28 ) $ 96.35 Outstanding at December 31, 2020 161 $ 151.62 1,390 $ 132.60 1,554 $ 40.40 3,105 $ 87.42
Schedule of Share-based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions [Table Text Block]	Year Ended December 31, 2020 2019 2018 Expected term (in years) 0.5 0.5 0.5 Expected volatility 48.9 % 37.0 % 29.5 % Risk-free interest rate 0.8 % 2.2 % 2.0 % Dividend yield 0.9 % 1.1 % 1.0 %

Note 9 - Dividends and Divide_2

Note 9 - Dividends and Dividend Equivalents (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Dividends Declared [Table Text Block]	Year Ended December 31, 2020 2019 2018 Dividend declared per share $ 2.00 $ 1.60 $ 1.20 Total amount $ 89,832 $ 69,196 $ 50,803

Note 10 - Other Income, Net (Ta

Note 10 - Other Income, Net (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Schedule of Other Nonoperating Income (Expense) [Table Text Block]	Year Ended December 31, 2020 2019 2018 Interest income $ 9,327 $ 7,305 $ 6,321 Amortization of premium on available-for-sale securities (2,979 ) (729 ) (1,353 ) Gain (loss) on deferred compensation plan investments 4,592 3,806 (1,022 ) Foreign currency exchange gain (loss) (1,364 ) (310 ) 953 Other 884 486 95 Total $ 10,460 $ 10,558 $ 4,994

Note 11 - Net Income Per Share

Note 11 - Net Income Per Share (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	Year Ended December 31, 2020 2019 2018 Numerator: Net income $ 164,375 $ 108,839 $ 105,268 Denominator: Weighted-average outstanding shares - basic 44,840 43,165 42,247 Effect of dilutive securities 2,174 2,598 2,355 Weighted-average outstanding shares - diluted 47,014 45,763 44,602 Net income per share: Basic $ 3.67 $ 2.52 $ 2.49 Diluted $ 3.50 $ 2.38 $ 2.36

Note 12 - Income Taxes (Tables)

Note 12 - Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table Text Block]	Year Ended December 31, 2020 2019 2018 United States $ 39,286 $ (4,134 ) $ (13,151 ) Foreign 130,056 117,254 131,633 Income before income taxes $ 169,342 $ 113,120 $ 118,482
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]	Year Ended December 31, 2020 2019 2018 Current: Federal $ 2,842 $ 1,682 $ 11,023 State (1 ) 8 4 Foreign 3,814 3,105 2,992 Deferred: Federal (1,221 ) (213 ) (797 ) Foreign (467 ) (301 ) (8 ) Income tax expense $ 4,967 $ 4,281 $ 13,214
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	Year Ended December 31, 2020 2019 2018 U.S. statutory federal tax rate 21.0 % 21.0 % 21.0 % Foreign income at lower rates (15.2 ) (20.7 ) (22.0 ) Impact of the 2017 Tax Act: One-time deemed repatriation transition tax - - 0.6 GILTI 11.1 11.0 14.4 Changes in valuation allowance 1.6 2.1 - Stock-based compensation (11.2 ) (1.5 ) (1.1 ) Tax credits, net of reserves (3.8 ) (6.2 ) (1.9 ) State income taxes (1.6 ) (0.7 ) - Other adjustments 1.0 (1.2 ) 0.2 Effective tax rate 2.9 % 3.8 % 11.2 %
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	December 31, 2020 2019 Deferred tax assets: Tax credits $ 23,501 $ 18,080 Stock-based compensation 2,392 6,237 Deferred compensation 7,895 7,110 Net operating losses 1,150 615 Other expenses not currently deductible 4,617 2,323 Deferred tax assets, gross 39,555 34,365 Valuation allowance (18,190 ) (15,411 ) Deferred tax assets, net of valuation allowance 21,365 18,954 Deferred tax liabilities: Depreciation and amortization (1,600 ) (1,259 ) Undistributed foreign earnings (77 ) (77 ) Other expenses currently deductible (1,132 ) (425 ) Deferred tax liabilities (2,809 ) (1,761 ) Net deferred tax assets $ 18,556 $ 17,193
Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]	Balance as of January 1, 2018 $ 16,272 Increase for tax position of prior year 1,474 Increase for tax position of current year 2,957 Decrease due to lapse of statute of limitation (212 ) Balance as of December 31, 2018 20,491 Increase for tax position of prior year 1,589 Increase for tax position of current year 4,663 Decrease due to settlement with tax authorities (560 ) Decrease due to lapse of statute of limitation (776 ) Balance as of December 31, 2019 25,407 Increase for tax position of current year 9,782 Decrease for tax position of prior year (907 ) Decrease due to settlement with tax authorities (560 ) Decrease due to lapse of statute of limitation (223 ) Balance as of December 31, 2020 $ 33,499

Note 13 - Commitments and Con_2

Note 13 - Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Schedule of Product Warranty Liability [Table Text Block]	Year Ended December 31, 2020 2019 2018 Balance at beginning of period $ 1,139 $ 4,564 $ 2,416 Warranty provision for product sales 7,584 891 6,586 Settlements made (843 ) (2,768 ) (1,402 ) Unused warranty provision (985 ) (1,548 ) (3,036 ) Balance at end of period $ 6,895 $ 1,139 $ 4,564

Note 15 - Significant Custome_2

Note 15 - Significant Customers (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Schedules of Concentration of Risk, by Risk Factor [Table Text Block]	Year Ended December 31, Customer 2020 2019 2018 Distributor A 24 % 23 % 22 % Distributor B 11 % * 10 % December 31, 2020 2019 Distributor A 24 % 24 % Distributor B 21 % 11 % Value-added reseller A 13 % 13 % Direct customer A 10 % *

Note 16 - Segment and Geograp_2

Note 16 - Segment and Geographic Information (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area [Table Text Block]	Year Ended December 31, Country or Region 2020 2019 2018 China $ 516,519 $ 382,740 $ 334,726 Taiwan 109,256 73,801 75,307 Europe 56,329 49,467 49,484 South Korea 64,093 43,900 41,238 Southeast Asia 42,403 32,031 36,495 Japan 35,461 27,812 26,853 United States 20,098 17,836 17,621 Other 293 334 658 Total $ 844,452 $ 627,921 $ 582,382
Revenue from External Customers by Products and Services [Table Text Block]	Year Ended December 31, Product Family 2020 2019 2018 DC to DC $ 800,478 $ 589,651 $ 537,512 Lighting Control 43,974 38,270 44,870 Total $ 844,452 $ 627,921 $ 582,382
Schedule of Disclosure on Geographic Areas, Long-Lived Assets in Individual Foreign Countries by Country [Table Text Block]	December 31, Country 2020 2019 2018 China $ 151,752 $ 113,888 $ 93,096 United States 101,768 94,671 39,054 Taiwan 18,797 17,652 16,972 Other 9,211 2,104 879 Total $ 281,528 $ 228,315 $ 150,001

Note 17 - Accumulated Other C_2

Note 17 - Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	Unrealized Gains (Losses) on Available-for-Sale Securities Foreign Currency Translation Adjustments Total Balance as of January 1, 2019 $ (1,638 ) $ (3,905 ) $ (5,543 ) Other comprehensive income (loss) before reclassifications 1,977 (1,706 ) 271 Amounts reclassified from accumulated other comprehensive loss (1 ) - (1 ) Tax effect (203 ) - (203 ) Net current period other comprehensive income (loss) 1,773 (1,706 ) 67 Balance as of December 31, 2019 135 (5,611 ) (5,476 ) Other comprehensive income before reclassifications 2,878 14,150 17,028 Amounts reclassified from accumulated other comprehensive income (loss) (1,087 ) - (1,087 ) Tax effect (325 ) - (325 ) Net current period other comprehensive income 1,466 14,150 15,616 Balance as of December 31, 2020 $ 1,601 $ 8,539 $ 10,140

Note 1 - Summary of Significa_3

Note 1 - Summary of Significant Accounting Policies (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Foreign Currency Transaction Gain (Loss), before Tax, Total	$ (1,364)	$ (310)	$ 953
Goodwill, Impairment Loss	$ 0	0	0
Minimum [Member]
Warranty Term (Year)	1 year
Maximum [Member]
Warranty Term (Year)	2 years
Building and Building Improvements [Member] | Minimum [Member]
Property, Plant and Equipment, Useful Life (Year)	20 years
Building and Building Improvements [Member] | Maximum [Member]
Property, Plant and Equipment, Useful Life (Year)	40 years
Computer Equipment [Member] | Minimum [Member]
Property, Plant and Equipment, Useful Life (Year)	3 years
Computer Equipment [Member] | Maximum [Member]
Property, Plant and Equipment, Useful Life (Year)	8 years
Transportation Equipment [Member] | Minimum [Member]
Property, Plant and Equipment, Useful Life (Year)	5 years
Transportation Equipment [Member] | Maximum [Member]
Property, Plant and Equipment, Useful Life (Year)	20 years
Furniture and Fixtures [Member] | Minimum [Member]
Property, Plant and Equipment, Useful Life (Year)	3 years
Furniture and Fixtures [Member] | Maximum [Member]
Property, Plant and Equipment, Useful Life (Year)	5 years
Interest and Other Income [Member]
Foreign Currency Transaction Gain (Loss), before Tax, Total	$ (1,400)	$ (300)	$ 1,000

Note 1 - Summary of Significa_4

Note 1 - Summary of Significant Accounting Policies - Summary of Deferred Compensation Plan (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred compensation plan assets	$ 46,146	$ 38,858
Deferred compensation plan liabilities	48,435	40,090
Other Long-term Assets [Member]
Deferred compensation plan assets	46,146	38,858
Accrued Compensation and Related Benefits [Member]
Deferred compensation plan liabilities	155	425
Other Long-term Liabilities [Member]
Deferred compensation plan liabilities	48,280	39,665
Cash Surrender Value [Member]
Deferred compensation plan assets	19,222	16,883
Mutual Funds and Money Market Funds, Fair Value [Member]
Deferred compensation plan assets	$ 26,924	$ 21,975

Note 2 - Revenue Recognition (D

Note 2 - Revenue Recognition (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Lapse Period for Consignment (Day)	60 days
Accounts Receivable, after Allowance for Credit Loss, Current, Total	$ 66,843	$ 52,704
Accounts Receivable, Allowance for Credit Loss, Ending Balance	0	0
Contract with Customer, Liability, Current	7,238	3,412
Contract with Customer, Liability, Revenue Recognized	$ 3,400
Minimum [Member]
Contract with Customer, Payment Term (Day)	30 days
Maximum [Member]
Contract with Customer, Payment Term (Day)	90 years
Certain Customers in China [Member]
Contract with Customer, Payment Term Required Prior to Shipping Products (Week)	14 days
Certain Customers in China [Member] | Accrued Liabilities, Current [Member]
Contract with Customer, Liability, Current	$ 7,200	$ 3,400
Customer Concentration Risk [Member] | Revenue Benchmark [Member]
Concentration Risk, Percentage	81.00%	83.00%	87.00%
Product [Member]
Percentage of Revenue	97.00%	99.00%	98.00%

Note 3 - Cash, Cash Equivalen_3

Note 3 - Cash, Cash Equivalents, Investments and Restricted Cash (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Gain (Loss) on Sale of Investments, Total	$ 1,100
Other-than-temporary Impairment Loss, Debt Securities, Available-for-sale, Total	0	$ 0
Redemption, Auction Rate Securities to Date	$ 40,300
Percentage of Auction Rate Securities Redeemed at Par Value	93.00%
Equity Securities without Readily Determinable Fair Value, Amount	$ 3,400	$ 0

Note 3 - Cash, Cash Equivalen_4

Note 3 - Cash, Cash Equivalents, Investments and Restricted Cash - Cash Equivalents, Short-term and Long-term Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Cash	$ 300,609	$ 144,860
Money market funds	34,335	28,100
Commercial paper	2,999	1,994
U.S. treasuries and government agency bonds	7,499	19,493
Total	597,974	458,535
Cash and cash equivalents	334,944	172,960
Short-term investments	260,169	282,437
Investment within other long-term assets	2,861	3,138
Corporate Debt Securities [Member]
Available-for-sale securities	249,671	260,950
Auction Rate Securities [Member]
Available-for-sale securities	$ 2,861	$ 3,138

Note 3 - Cash, Cash Equivalen_5

Note 3 - Cash, Cash Equivalents, Investments and Restricted Cash - Investment Maturity Classification (Details) $ in Thousands	Dec. 31, 2020USD ($)
Due in less than 1 year, Amortized cost	$ 97,773
Due in less than 1 year, fair value	98,036
Due in 1 - 5 years, Amortized cost	160,316
Due in 1 - 5 years	162,133
Due in greater than 5 years, Amortized cost	3,020
Due in greater than 5 years	2,861
Total, Amortized cost	261,109
Total	$ 263,030

Note 3 - Cash, Cash Equivalen_6

Note 3 - Cash, Cash Equivalents, Investments and Restricted Cash - Unrealized Gains and Losses on Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Amortized Cost	$ 295,444	$ 313,546
Unrealized Gains	2,179	390
Unrealized Losses	(258)	(261)
Total Fair Value	297,365	313,675
Money Market Funds [Member]
Amortized Cost	34,335	28,100
Unrealized Gains	0	0
Unrealized Losses	0	0
Total Fair Value	34,335	28,100
Corporate Debt Securities [Member]
Amortized Cost	247,591	260,645
Unrealized Gains	2,177	383
Unrealized Losses	(97)	(78)
Total Fair Value	249,671	260,950
Commercial Paper [Member]
Amortized Cost	2,999	1,994
Unrealized Gains	0	0
Unrealized Losses	0	0
Total Fair Value	2,999	1,994
US Government Agencies Short-term Debt Securities [Member]
Amortized Cost	7,499	19,487
Unrealized Gains	2	7
Unrealized Losses	(2)	(1)
Total Fair Value	7,499	19,493
Auction Rate Securities [Member]
Amortized Cost	3,020	3,320
Unrealized Gains	0	0
Unrealized Losses	(159)	(182)
Total Fair Value	$ 2,861	$ 3,138

Note 3 - Cash, Cash Equivalen_7

Note 3 - Cash, Cash Equivalents, Investments and Restricted Cash - Continuous Unrealized Loss Position (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Continuous Unrealized Loss Position, Less than 12 Months	$ 65,142	$ 83,119
Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(99)	(64)
Continuous Unrealized Loss Position, 12 Months or Longer	2,861	14,274
Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(159)	(197)
Unrealized Loss Position, Total	68,003	97,393
Unrealized Loss Position, Accumulated Loss, Total	(258)	(261)
Corporate Debt Securities [Member]
Continuous Unrealized Loss Position, Less than 12 Months	59,144	82,126
Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(97)	(63)
Continuous Unrealized Loss Position, 12 Months or Longer	0	11,136
Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	(15)
Unrealized Loss Position, Total	59,144	93,262
Unrealized Loss Position, Accumulated Loss, Total	(97)	(78)
US Treasury and Government Short-term Debt Securities [Member]
Continuous Unrealized Loss Position, Less than 12 Months	5,998
Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(2)
Continuous Unrealized Loss Position, 12 Months or Longer	0
Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0
Unrealized Loss Position, Total	5,998
Unrealized Loss Position, Accumulated Loss, Total	(2)
US Government Agencies Short-term Debt Securities [Member]
Continuous Unrealized Loss Position, Less than 12 Months		993
Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(1)
Continuous Unrealized Loss Position, 12 Months or Longer		0
Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0
Unrealized Loss Position, Total		993
Unrealized Loss Position, Accumulated Loss, Total		(1)
Auction Rate Securities [Member]
Continuous Unrealized Loss Position, Less than 12 Months	0	0
Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	0
Continuous Unrealized Loss Position, 12 Months or Longer	2,861	3,138
Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(159)	(182)
Unrealized Loss Position, Total	2,861	3,138
Unrealized Loss Position, Accumulated Loss, Total	$ (159)	$ (182)

Note 3 - Cash, Cash Equivalen_8

Note 3 - Cash, Cash Equivalents, Investments and Restricted Cash - Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash and cash equivalents	$ 334,944	$ 172,960
Restricted cash included in other long-term assets	127	116
Total cash, cash equivalents and restricted cash reported on the Consolidated Statements of Cash Flows	$ 335,071	$ 173,076	$ 172,818	$ 82,874

Note 4 - Fair Value Measureme_3

Note 4 - Fair Value Measurements - Financial Assets and Liabilities, Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Total Fair Value	$ 297,365	$ 313,675
Assets, fair value	324,289	335,650
Fair Value, Inputs, Level 1 [Member]
Assets, fair value	61,259	50,075
Fair Value, Inputs, Level 2 [Member]
Assets, fair value	260,169	282,437
Fair Value, Inputs, Level 3 [Member]
Assets, fair value	2,861	3,138
Money Market Funds [Member]
Total Fair Value	34,335	28,100
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Total Fair Value	34,335	28,100
Money Market Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Total Fair Value	0	0
Money Market Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Total Fair Value	0	0
Corporate Debt Securities [Member]
Total Fair Value	249,671	260,950
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Total Fair Value	0	0
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Total Fair Value	249,671	260,950
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Total Fair Value	0	0
Commercial Paper [Member]
Total Fair Value	2,999	1,994
Commercial Paper [Member] | Fair Value, Inputs, Level 1 [Member]
Total Fair Value	0	0
Commercial Paper [Member] | Fair Value, Inputs, Level 2 [Member]
Total Fair Value	2,999	1,994
Commercial Paper [Member] | Fair Value, Inputs, Level 3 [Member]
Total Fair Value	0	0
US Government Agencies Short-term Debt Securities [Member]
Total Fair Value	7,499	19,493
US Government Agencies Short-term Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Total Fair Value	0	0
US Government Agencies Short-term Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Total Fair Value	7,499	19,493
US Government Agencies Short-term Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Total Fair Value	0	0
Auction Rate Securities [Member]
Total Fair Value	2,861	3,138
Auction Rate Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Total Fair Value	0	0
Auction Rate Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Total Fair Value	0	0
Auction Rate Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Total Fair Value	2,861	3,138
Mutual Fund [Member]
Total Fair Value	26,924	21,975
Mutual Fund [Member] | Fair Value, Inputs, Level 1 [Member]
Total Fair Value	26,924	21,975
Mutual Fund [Member] | Fair Value, Inputs, Level 2 [Member]
Total Fair Value	0	0
Mutual Fund [Member] | Fair Value, Inputs, Level 3 [Member]
Total Fair Value	$ 0	$ 0

Note 4 - Fair Value Measureme_4

Note 4 - Fair Value Measurements - Level 3 Investments (Details) - Auction Rate Securities [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Balance, auction rate securities	$ 3,138	$ 3,241
Change in unrealized gain included in other comprehensive income	23	147
Sale and settlement at par	(300)	(250)
Balance, auction rate securities	$ 2,861	$ 3,138

Note 4 - Fair Value Measureme_5

Note 4 - Fair Value Measurements - Discounted Cash Flow Assumptions (Details)		12 Months Ended
		Dec. 31, 2020		Dec. 31, 2019
Minimum [Member]
Time-to-liquidity (Year)		2 years	[1]	2 years
Discount rate		3.50%	[1]	4.00%
Maximum [Member]
Time-to-liquidity (Year)		3 years	[1]	3 years
Discount rate		7.90%	[1]	8.30%
Weighted Average [Member]
Time-to-liquidity (Year)	[1]	2 years 6 months
Discount rate	[1]	(5.60%)
[1]	The parenthetical value represents the weighted average assumption, which was calculated based on the relative fair value of the securities.

Note 5 - Balance Sheet Compon_3

Note 5 - Balance Sheet Components (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Depreciation, Total	$ 18.9	$ 14.5	$ 11.4

Note 5 - Balance Sheet Compon_4

Note 5 - Balance Sheet Components - Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Raw materials	$ 25,503	$ 22,872
Work in process	77,100	42,681
Finished goods	54,459	61,947
Total	$ 157,062	$ 127,500

Note 5 - Balance Sheet Compon_5

Note 5 - Balance Sheet Components - Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
RSU tax withholding proceeds receivable	$ 12,504	$ 6,106
Prepaid expense	5,032	7,991
Accrued interest receivable	1,914	2,490
Assets for product returns	1,684	1,585
Other	1,846	1,433
Total	$ 22,980	$ 19,605

Note 5 - Balance Sheet Compon_6

Note 5 - Balance Sheet Components - Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property and equipment	$ 424,677	$ 347,246
Less: accumulated depreciation and amortization	(143,149)	(118,931)
Total	281,528	228,315
Land [Member]
Property and equipment	35,432	35,040
Production Equipment and Software [Member]
Property and equipment	163,317	134,292
Building and Building Improvements [Member]
Property and equipment	142,869	131,057
Transportation Equipment [Member]
Property and equipment	18,396	16,510
Leasehold Improvements [Member]
Property and equipment	8,705	6,583
Furniture and Fixtures [Member]
Property and equipment	6,383	4,660
Construction in Progress [Member]
Property and equipment	$ 49,575	$ 19,104

Note 5 - Balance Sheet Compon_7

Note 5 - Balance Sheet Components - Other Long-term Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred compensation plan assets	$ 46,146	$ 38,858
Operating lease ROU assets	3,719	2,863
Prepaid expense	2,340	2,687
Debt investment	2,861	3,138
Equity investment in a privately held company	3,400	0
Other	1,372	1,544
Total	$ 59,838	$ 49,090

Note 5 - Balance Sheet Compon_8

Note 5 - Balance Sheet Components - Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Dividends and dividend equivalents	$ 26,435	$ 21,747
Stock rotation and sales returns	6,005	5,530
Accrued purchases of property and equipment	5,841	4,678
Income tax payable	3,755	2,435
Customer prepayments	7,238	3,412
Commissions	1,107	1,425
Warranty	6,895	1,139
Other	4,278	3,170
Total	62,960	44,790
Accrued Liabilities, Current [Member]
Operating lease liabilities	$ 1,406	$ 1,254

Note 5 - Balance Sheet Compon_9

Note 5 - Balance Sheet Components - Other Long-term Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred compensation plan liabilities	$ 48,280	$ 39,665
Dividend equivalents	7,871	6,265
Other	29	30
Total	57,873	47,063
Other Long-term Liabilities [Member]
Operating lease liabilities	$ 1,693	$ 1,103

Note 6 - Real Estate Transact_3

Note 6 - Real Estate Transaction (Details Textual) $ in Millions	1 Months Ended
	Mar. 31, 2019USD ($)
Payments to Acquire Real Estate, Total	$ 52.9
Real Estate, Capitalized Transaction Costs	$ 0.4
Leases, Acquired-in-Place [Member]
Finite-Lived Intangible Asset, Useful Life (Year)	3 years 6 months
Building [Member]
Property, Plant and Equipment, Useful Life (Year)	40 years

Note 6 - Real Estate Transact_4

Note 6 - Real Estate Transaction - Allocation of Consideration (Details) - Property in Kirkland, Washington [Member] $ in Thousands	Mar. 31, 2019USD ($)
Building	$ 30,078
Land	22,254
In-place leases	981
Total	$ 53,313

Note 7 - Leases (Details Textua

Note 7 - Leases (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2019
Operating Lease, Right-of-Use Asset	$ 3,719	$ 2,863
Lessee, Operating Lease, Lease Not yet Commenced, Future Lease Obligations	4,600
Operating Lease, Lease Income, Lease Payments	1,900	1,800
Accounting Standards Update 2016-02 [Member]
Operating Lease, Right-of-Use Asset			$ 2,300
Other Assets [Member]
Operating Lease, Right-of-Use Asset	3,700	2,900
Other Liabilities [Member]
Operating Lease, Liability, Total	$ 3,100	$ 2,400
Maximum [Member]
Lessee, Operating Lease, Renewal Term (Year)	2 years
Lessee, Operating Lease, Lease Not yet Commenced, Term of Contract (Year)	4 years
Lessor, Operating Lease, Remaining Lease Term (Year)	4 years
Lessor, Operating Lease, Renewal Term (Year)	5 years
Minimum [Member]
Lessee, Operating Lease, Lease Not yet Commenced, Term of Contract (Year)	1 year
Lessor, Operating Lease, Remaining Lease Term (Year)	2 years

Note 7 - Leases - Leases Cost (

Note 7 - Leases - Leases Cost (Details) - USD ($) $ in Thousands		12 Months Ended		22 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Oct. 26, 2020
Operating lease costs		$ 1,488	$ 1,509
Other		300	465
Total lease costs		1,788	$ 1,974
Operating cash flows from operating leases		1,526		$ 1,364
ROU assets obtained in exchange for new operating lease liabilities (1)	[1]	$ 2,181		$ 3,667
Weighted-average remaining lease term (in years) (Year)		2 years 8 months 12 days	2 years 1 month 6 days
Weighted-average discount rate		2.70%	3.70%
[1]	For the year ended December 31, 2019, the amount includes $2.3 million for operating leases existing on January 1, 2019, the adoption date of ASU No. 2016-02, Leases (Topic 842).

Note 7 - Leases - Maturities of

Note 7 - Leases - Maturities of Lease Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
2021	$ 1,491
2022	993
2023	405
2024	199
2025	139
Total remaining lease payments	3,227
Less: imputed interest	(128)
Accrued Liabilities and Other Long-term Liabilities [Member]
Total lease liabilities	3,099
Accrued Liabilities, Current [Member]
Current liabilities	1,406	$ 1,254
Other Long-term Liabilities [Member]
Long-term liabilities	$ 1,693	$ 1,103

Note 7 - Leases - Maturities _2

Note 7 - Leases - Maturities of Income Related to Lease Payments (Details) $ in Thousands	Dec. 31, 2020USD ($)
2021	$ 2,153
2022	2,073
2023	1,400
2024	553
2025	59
Total	$ 6,238

Note 8 - Stock-based Compensa_3

Note 8 - Stock-based Compensation (Details Textual) $ / shares in Units, $ in Thousands	Jun. 11, 2020shares	Jan. 01, 2020	Jul. 31, 2020USD ($)$ / sharesshares	Feb. 29, 2020USD ($)$ / sharesshares	Feb. 28, 2019USD ($)$ / sharesshares	Oct. 31, 2018USD ($)$ / sharesshares	Feb. 28, 2018USD ($)$ / sharesshares	Dec. 31, 2015$ / sharesshares	Dec. 31, 2020USD ($)$ / sharesshares	Dec. 31, 2019USD ($)$ / sharesshares	Dec. 31, 2018USD ($)$ / sharesshares	Dec. 31, 2015USD ($)$ / shares	Dec. 31, 2020USD ($)$ / sharesshares	Nov. 13, 2014shares
Proceeds, Issuance of Shares, Share-based Payment Arrangement, Excluding Option Exercised | $									$ 18,767	$ 16,650	$ 10,637
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)									703,000	564,000	1,363,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares									$ 175.12	$ 103.68	$ 80.62
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period (in shares)									1,623,000	1,083,000	853,000
Share-based Payment Arrangement, Expense | $									$ 85,551	$ 78,699	$ 60,607
Proceeds from Stock Plans | $									3,819	3,277	3,028
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Vested | $									326,200	138,300	90,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Outstanding | $									$ 1,100,000				$ 1,100,000
Share Price (in dollars per share) | $ / shares									$ 366.23				$ 366.23
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total | $									$ 136,300				$ 136,300
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)									2 years 2 months 12 days
Proceeds, Issuance of Shares, Share-based Payment Arrangement, Excluding Option Exercised | $									$ 18,800	$ 16,600	$ 10,600
Time-Based RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)									76,000	52,000	133,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares									$ 189.28	$ 141.32	$ 114.36
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period (in shares)									86,000	103,000	136,000
Time-Based RSUs [Member] | Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)									4 years
Time-Based RSUs [Member] | Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)									1 year
PSU 2020 [Member]
Share Price (in dollars per share) | $ / shares				$ 182.62
Share-based Compensation Arrangement by Share-based Payment Award, Price Per Share Payable Upon Vesting of Equity Instruments Other than Options (in dollars per share) | $ / shares				30
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares				$ 182.62
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term (Year)				2 years
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate				33.60%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate				1.40%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate				1.10%
PSU 2020 [Member] | Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)				100,000
Share-based Compensation Arrangement by Share-based Payment Award, Vesting, Measurement Period of Relative Revenue Growth Rate to Industry Average (Year)				2 years
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Maximum Percentage Allowed				300.00%
Maximum Stock Compensation Costs | $				$ 51,100
PSU 2020 [Member] | Executive Officer [Member] | Vesting First Quarter of 2022 if Performance Conditions are Met [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage				50.00%
PSU 2020 [Member] | Non-Executive Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)				30,000
Share-based Compensation Arrangement by Share-based Payment Award, Vesting, Measurement Period of Relative Revenue Growth Rate to Industry Average (Year)				2 years
Maximum Stock Compensation Costs | $				$ 12,800
PSU 2020 [Member] | Non-Executive Employees [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Minimum Percentage Allowed				200.00%
PSU 2020 [Member] | Non-Executive Employees [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Maximum Percentage Allowed				300.00%
PSU 2020 [Member] | Non-Executive Employees [Member] | Vesting First Quarter of 2020 if Performance Conditions are Met [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage				50.00%
PSU 2020 [Member] | Non-Executive Employees [Member] | Annual or Quarterly Vesting of Awards Not Based on Performance [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)				2 years
MPSUs 2020 [Member]
Share Price (in dollars per share) | $ / shares									$ 248.71				$ 248.71
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Maximum Percentage Allowed			500.00%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term (Year)									4 years
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate									38.80%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate									0.20%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate									0.80%
Share-based Compensation Arrangement by Share-based Payment Award, Number of Price Targets			5
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period (in shares)									221,000
Share-based Payment Arrangement, Expense | $			$ 42,100
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Discount for Postvesting Restrictions									8.90%
MPSUs 2020 [Member] | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award, Stock Price Target (in dollars per share) | $ / shares			$ 260
MPSUs 2020 [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award, Stock Price Target (in dollars per share) | $ / shares			$ 300
MPSUs 2020 [Member] | Vest on July, 2023 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage			75.00%
MPSUs 2020 [Member] | Vest on July 20, 2024 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage			25.00%
MPSUs 2020 [Member] | Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)			43,000
MPSUs 2020 [Member] | Key Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)			2,000
PSU 2019 [Member]
Share Price (in dollars per share) | $ / shares					$ 130.67	$ 108.43
Share-based Compensation Arrangement by Share-based Payment Award, Price Per Share Payable Upon Vesting of Equity Instruments Other than Options (in dollars per share) | $ / shares					$ 30
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term (Year)					2 years 7 months 6 days	2 years 10 months 24 days
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate					29.00%	28.70%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate					2.50%	2.90%
PSU 2019 [Member] | Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)					151,000				454,000
Share-based Compensation Arrangement by Share-based Payment Award, Vesting, Measurement Period of Relative Revenue Growth Rate to Industry Average (Year)					2 years
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Maximum Percentage Allowed					300.00%
Maximum Stock Compensation Costs | $					$ 46,600
PSU 2019 [Member] | Executive Officer [Member] | Vesting First Quarter of 2021 if Performance Conditions are Met [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage					50.00%
PSU 2019 [Member] | Executive Officer [Member] | Vesting Over Two Years Following First Quarter of 2021 on Quarterly Basis [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage					50.00%
PSU 2019 [Member] | Non-Executive Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)						53,000			100,000
Share-based Compensation Arrangement by Share-based Payment Award, Vesting, Measurement Period of Relative Revenue Growth Rate to Industry Average (Year)						2 years
Maximum Stock Compensation Costs | $						$ 8,100
Share-based Compensation Arrangement by Share-based Payment Award, Price Per Share Payable Upon Vesting of Equity Instruments Other than Options (in dollars per share) | $ / shares						$ 30
PSU 2019 [Member] | Non-Executive Employees [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Minimum Percentage Allowed						200.00%
PSU 2019 [Member] | Non-Executive Employees [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Maximum Percentage Allowed						300.00%
PSU 2019 [Member] | Non-Executive Employees [Member] | Vesting First Quarter of 2021 if Performance Conditions are Met [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage						50.00%
PSU 2019 [Member] | Non-Executive Employees [Member] | Vesting Over Two Years Following First Quarter of 2021 on an Annual or Quarterly Basis [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage						50.00%
PSU 2018 [Member]
Share Price (in dollars per share) | $ / shares							$ 110
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term (Year)							2 years 7 months 6 days
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate							27.50%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate							2.30%
PSU 2018 [Member] | Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)							188,000		558,000
Share-based Compensation Arrangement by Share-based Payment Award, Vesting, Measurement Period of Relative Revenue Growth Rate to Industry Average (Year)							2 years
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Maximum Percentage Allowed							300.00%
Maximum Stock Compensation Costs | $							$ 45,600
PSU 2018 [Member] | Executive Officer [Member] | Vesting First Quarter of 2020 if Performance Conditions are Met [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage							50.00%
PSU 2018 [Member] | Executive Officer [Member] | Vesting Over Two Years Following First Quarter of 2020 on Quarterly or Annual Basis [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage							50.00%
PSU 2018 [Member] | Non-Executive Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)							44,000		75,000
Share-based Compensation Arrangement by Share-based Payment Award, Vesting, Measurement Period of Relative Revenue Growth Rate to Industry Average (Year)							2 years
Maximum Stock Compensation Costs | $							$ 6,000
Share-based Compensation Arrangement by Share-based Payment Award, Price Per Share Payable Upon Vesting of Equity Instruments Other than Options (in dollars per share) | $ / shares							$ 30
PSU 2018 [Member] | Non-Executive Employees [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Minimum Percentage Allowed							200.00%
PSU 2018 [Member] | Non-Executive Employees [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Minimum Percentage Allowed							300.00%
PSU 2018 [Member] | Non-Executive Employees [Member] | Vesting First Quarter of 2020 if Performance Conditions are Met [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage							50.00%
PSU 2018 [Member] | Non-Executive Employees [Member] | Vesting Over Two Years Following First Quarter of 2020 on an Annual or Quarterly Basis [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage							50.00%
2015 MPSUs [Member]
Share Price (in dollars per share) | $ / shares								$ 61.35				$ 61.35
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Maximum Percentage Allowed								500.00%
Maximum Stock Compensation Costs | $												$ 24,600
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate												33.20%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate												1.30%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Discount for Postvesting Restrictions												7.80%
Number of MPSU Tranches								4
Total MSUs Earned (in shares)													600,000
Share-based Compensation Arrangement by Share-based Payment Award, Post-Award Vesting Period, Restriction Period on Sales (Year)		2 years
2015 MPSUs [Member] | Share-based Payment Arrangement, Tranche One [Member]
Maximum Stock Compensation Costs | $												$ 8,300
Share-based Compensation Arrangement by Share-based Payment Award, Number of Price Targets								5				5
2015 MPSUs [Member] | Share-based Payment Arrangement, Tranche One [Member] | Minimum [Member]
Market Awards Price Targets (in dollars per share) | $ / shares								$ 71.36
2015 MPSUs [Member] | Share-based Payment Arrangement, Tranche One [Member] | Maximum [Member]
Market Awards Price Targets (in dollars per share) | $ / shares								$ 95.57
2015 MPSUs [Member] | Second, Third, and Fourth Tranches [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Price Targets								5				5
Total number of performance conditions								6
2015 MPSUs [Member] | Share-based Payment Arrangement, Tranche Two [Member]
Maximum Stock Compensation Costs | $												$ 4,500
2015 MPSUs [Member] | Share-based Payment Arrangement, Tranche Two [Member] | Minimum [Member]
Market Awards Price Targets (in dollars per share) | $ / shares								$ 89.56
2015 MPSUs [Member] | Share-based Payment Arrangement, Tranche Two [Member] | Maximum [Member]
Market Awards Price Targets (in dollars per share) | $ / shares								106.81
2015 MPSUs [Member] | Share-based Payment Arrangement, Tranche Three [Member]
Maximum Stock Compensation Costs | $												5,200
2015 MPSUs [Member] | Share-based Payment Arrangement, Tranche Three [Member] | Minimum [Member]
Market Awards Price Targets (in dollars per share) | $ / shares								120.80
2015 MPSUs [Member] | Share-based Payment Arrangement, Tranche Three [Member] | Maximum [Member]
Market Awards Price Targets (in dollars per share) | $ / shares								135.48
2015 MPSUs [Member] | Share-based Compensation Award, Tranche Four [Member]
Maximum Stock Compensation Costs | $												$ 6,600
2015 MPSUs [Member] | Share-based Compensation Award, Tranche Four [Member] | Minimum [Member]
Market Awards Price Targets (in dollars per share) | $ / shares								126.08
2015 MPSUs [Member] | Share-based Compensation Award, Tranche Four [Member] | Maximum [Member]
Market Awards Price Targets (in dollars per share) | $ / shares								$ 136.79
2015 MPSUs [Member] | Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)								86,000
2015 MPSUs [Member] | Non-Executive Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)								41,000
MSUs 2018 [Member]
Share Price (in dollars per share) | $ / shares						$ 108.43
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Maximum Percentage Allowed						500.00%
Maximum Stock Compensation Costs | $						$ 39,900
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate						31.60%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate						3.00%
Share-based Compensation Arrangement by Share-based Payment Award, Number of Price Targets						5
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Discount for Postvesting Restrictions						8.70%
Total MSUs Earned (in shares)										600,000
Share-based Compensation Arrangement by Share-based Payment Award, Post-Award Vesting Period, Restriction Period on Sales (Year)						2 years
MSUs 2018 [Member] | Minimum [Member]
Market Awards Price Targets (in dollars per share) | $ / shares						$ 140
MSUs 2018 [Member] | Maximum [Member]
Market Awards Price Targets (in dollars per share) | $ / shares						$ 172
MSUs 2018 [Member] | Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)						60,000
MSUs 2018 [Member] | Non-Executive Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)						60,000
2013 MSU's [Member]
Share Price (in dollars per share) | $ / shares						$ 31.73
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Maximum Percentage Allowed						500.00%
Maximum Stock Compensation Costs | $						$ 38,200
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate						38.70%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate						1.60%
Share-based Compensation Arrangement by Share-based Payment Award, Number of Price Targets						5
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Discount for Postvesting Restrictions						0.00%
Total MSUs Earned (in shares)						1,800,000
2013 MSU's [Member] | Minimum [Member]
Market Awards Price Targets (in dollars per share) | $ / shares						$ 40
2013 MSU's [Member] | Maximum [Member]
Market Awards Price Targets (in dollars per share) | $ / shares						$ 56
2013 MSU's [Member] | Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)						276,000
2013 MSU's [Member] | Non-Executive Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)						84,000
The2014 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)														5,500,000
Amended and Restated 2014 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized (in shares)	10,500,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)									6,000,000				6,000,000
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)									4.5				4.5
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total | $									$ 200				$ 200
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Number of Shares Per Employee (in shares)									2,000
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Number of Shares per Employee Value (in shares)									25,000
Share-based Compensation Arrangement by Share-based Payment Award, Automatic Increase Shares (in shares)									1,000,000
Share-basedCompensation Arrangement by Share-based Payment Award, Other Than Options, Percent Increases in Period									2.00%
Stock Issued During Period, Shares, Employee Stock Purchase Plans (in shares)									28,000	28,000	33,000
Employee Stock Purchase Plan Shares Issued, Intrinsic Value | $									$ 2,500	$ 700	$ 1,100
Proceeds from Stock Plans | $									$ 3,800	$ 3,300	$ 3,000

Note 8 - Stock-based Compensa_4

Note 8 - Stock-based Compensation - Stock-based Compensation Plan Expenses (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share based compensation expense		$ 85,551	$ 78,699	$ 60,607
Tax benefit related to stock-based compensation	[1]	1,855	2,754	4,383
Cost of Sales [Member]
Share based compensation expense		2,592	2,409	1,888
Research and Development Expense [Member]
Share based compensation expense		20,033	19,584	15,990
Selling, General and Administrative Expenses [Member]
Share based compensation expense		$ 62,926	$ 56,706	$ 42,729
[1]	Amount reflects the tax benefit related to stock-based compensation recorded for equity awards that are expected to generate tax deductions when they vest in future periods.

Note 8 - Stock-based Compensa_5

Note 8 - Stock-based Compensation - RSU Summary (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Beginning balance (in shares)	4,053,000	4,633,000	4,144,000
Weighted-Average Grant Date Fair Value Per Share, beginning balance (in dollars per share)	$ 59.16	$ 50.94	$ 39.91
Granted (in shares)	703,000	564,000	1,363,000
Weighted-Average Grant Date Fair Value Per Share, granted (in dollars per share)	$ 175.12	$ 103.68	$ 80.62
Vested (in shares)	(1,623,000)	(1,083,000)	(853,000)
Weighted-Average Grant Date Fair Value Per Share, vested (in dollars per share)	$ 54.70	$ 47.34	$ 44.13
Forfeited (in shares)	(28,000)	(61,000)	(21,000)
Weighted-Average Grant Date Fair Value Per Share, forfeited (in dollars per share)	$ 96.35	$ 57.01	$ 76.92
Ending balance (in shares)	3,105,000	4,053,000	4,633,000
Weighted-Average Grant Date Fair Value Per Share, ending balance (in dollars per share)	$ 87.42	$ 59.16	$ 50.94
Time-Based RSUs [Member]
Beginning balance (in shares)	180,000	240,000	258,000
Weighted-Average Grant Date Fair Value Per Share, beginning balance (in dollars per share)	$ 115.45	$ 95.38	$ 66.30
Granted (in shares)	76,000	52,000	133,000
Weighted-Average Grant Date Fair Value Per Share, granted (in dollars per share)	$ 189.28	$ 141.32	$ 114.36
Vested (in shares)	(86,000)	(103,000)	(136,000)
Weighted-Average Grant Date Fair Value Per Share, vested (in dollars per share)	$ 110.67	$ 81.53	$ 60.23
Forfeited (in shares)	(9,000)	(9,000)	(15,000)
Weighted-Average Grant Date Fair Value Per Share, forfeited (in dollars per share)	$ 138.34	$ 117.31	$ 82.20
Ending balance (in shares)	161,000	180,000	240,000
Weighted-Average Grant Date Fair Value Per Share, ending balance (in dollars per share)	$ 151.62	$ 115.45	$ 95.38
PSUs and MPSUs [Member]
Beginning balance (in shares)	1,987,000	2,174,000	2,266,000
Weighted-Average Grant Date Fair Value Per Share, beginning balance (in dollars per share)	$ 74.50	$ 61.61	$ 48.59
Granted (in shares)	627,000	512,000	630,000	[1]
Weighted-Average Grant Date Fair Value Per Share, granted (in dollars per share)	$ 173.40	$ 99.88	$ 85.06
Vested (in shares)	(1,213,000)	(656,000)	(717,000)
Weighted-Average Grant Date Fair Value Per Share, vested (in dollars per share)	$ 59.03	$ 53.72	$ 41.08
Forfeited (in shares)	(11,000)	(43,000)	(5,000)
Weighted-Average Grant Date Fair Value Per Share, forfeited (in dollars per share)	$ 84.48	$ 42.72	$ 63.16
Ending balance (in shares)	1,390,000	1,987,000	2,174,000
Weighted-Average Grant Date Fair Value Per Share, ending balance (in dollars per share)	$ 132.60	$ 74.50	$ 61.61
MSUs [Member]
Beginning balance (in shares)	1,886,000	2,219,000	1,620,000
Weighted-Average Grant Date Fair Value Per Share, beginning balance (in dollars per share)	$ 37.63	$ 35.69	$ 23.57
Granted (in shares)	0	0	600,000
Weighted-Average Grant Date Fair Value Per Share, granted (in dollars per share)	$ 0	$ 0	$ 68.48
Vested (in shares)	(324,000)	(324,000)	0
Weighted-Average Grant Date Fair Value Per Share, vested (in dollars per share)	$ 23.57	$ 23.57	$ 0
Forfeited (in shares)	(8,000)	(9,000)	(1,000)
Weighted-Average Grant Date Fair Value Per Share, forfeited (in dollars per share)	$ 68.48	$ 68.48	$ 68.48
Ending balance (in shares)	1,554,000	1,886,000	2,219,000
Weighted-Average Grant Date Fair Value Per Share, ending balance (in dollars per share)	$ 40.40	$ 37.63	$ 35.69
[1]	Amount reflects the number of awards that may ultimately be earned based on management's probability assessment of the achievement of performance conditions at each reporting period.

Note 8 - Stock-based Compensa_6

Note 8 - Stock-based Compensation - Valuation Assumptions (Details) - 2004 Employee Stock Plan [Member] - Employee Stock Purchase Plan [Member]	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Expected term (Year)	6 months	6 months	6 months
Expected volatility	48.90%	37.00%	29.50%
Risk-free interest rate	0.80%	2.20%	2.00%
Dividend yield	0.90%	1.10%	1.00%

Note 9 - Dividends and Divide_3

Note 9 - Dividends and Dividend Equivalents (Details Textual) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Dividends Payable, Current	$ 22.6	$ 17.4
Accrued Dividend Equivalents	$ 11.7	$ 10.6

Note 9 - Dividends and Divide_4

Note 9 - Dividends and Dividend Equivalents - Cash Dividends (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Dividend declared per share (in dollars per share)	$ 2	$ 1.60	$ 1.20
Total amount	$ 89,832	$ 69,196	$ 50,803

Note 10 - Other Income, Net - I

Note 10 - Other Income, Net - Interest and Other Income Components (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Interest income	$ 9,327	$ 7,305	$ 6,321
Amortization of premium on available-for-sale securities	(2,979)	(729)	(1,353)
Gain (loss) on deferred compensation plan investments	4,592	3,806	(1,022)
Foreign currency exchange gain (loss)	(1,364)	(310)	953
Other	884	486	95
Total	$ 10,460	$ 10,558	$ 4,994

Note 11 - Net Income Per Shar_2

Note 11 - Net Income Per Share - Net Income Per Share Basic and Diluted (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net income	$ 164,375	$ 108,839	$ 105,268
Weighted-average outstanding shares - basic (in shares)	44,840	43,165	42,247
Effect of dilutive securities (in shares)	2,174	2,598	2,355
Weighted-average outstanding shares - diluted (in shares)	47,014	45,763	44,602
Earnings per share, basic (in dollars per share)	$ 3.67	$ 2.52	$ 2.49
Earnings per share, diluted (in dollars per share)	$ 3.50	$ 2.38	$ 2.36

Note 12 - Income Taxes (Details

Note 12 - Income Taxes (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Undistributed Earnings of Foreign Subsidiaries	$ 27,700	$ 32,900
Percent of Dividend Received Deduction	100.00%
Unrecognized Tax Benefits, Ending Balance	$ 33,499	25,407	$ 20,491	$ 16,272
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	24,300	17,300
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	2,400	1,600
Domestic Tax Authority [Member]
Operating Loss Carryforwards, Total	0
Domestic Tax Authority [Member] | Research Tax Credit Carryforward [Member]
Tax Credit Carryforward, Amount	7,100
State and Local Jurisdiction [Member] | Research Tax Credit Carryforward [Member]
Tax Credit Carryforward, Amount	30,500
State and Local Jurisdiction [Member] | Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards, Total	20,200
Bermuda Subsidiary [Member]
Foreign Earnings Repatriated	$ 30,000	$ 75,000

Note 12 - Income Taxes - Compon

Note 12 - Income Taxes - Components of Income Before Income Tax (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
United States	$ 39,286	$ (4,134)	$ (13,151)
Foreign	130,056	117,254	131,633
Income before income taxes	$ 169,342	$ 113,120	$ 118,482

Note 12 - Income Taxes - Comp_2

Note 12 - Income Taxes - Components of Income Tax Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Federal	$ 2,842	$ 1,682	$ 11,023
State	(1)	8	4
Foreign	3,814	3,105	2,992
Federal	(1,221)	(213)	(797)
Foreign	(467)	(301)	(8)
Income tax expense	$ 4,967	$ 4,281	$ 13,214

Note 12 - Income Taxes - Income

Note 12 - Income Taxes - Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
U.S. statutory federal tax rate	21.00%	21.00%	21.00%
Foreign income at lower rates	(15.20%)	(20.70%)	(22.00%)
One-time deemed repatriation transition tax	0.00%	0.00%	0.60%
GILTI	11.10%	11.00%	14.40%
Changes in valuation allowance	1.60%	2.10%	0.00%
Stock-based compensation	(11.20%)	(1.50%)	(1.10%)
Tax credits, net of reserves	(3.80%)	(6.20%)	(1.90%)
State income taxes	(1.60%)	(0.70%)	0.00%
Other adjustments	1.00%	(1.20%)	0.20%
Effective tax rate	2.90%	3.80%	11.20%

Note 12 - Income Taxes - Deferr

Note 12 - Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Tax credits	$ 23,501	$ 18,080
Stock-based compensation	2,392	6,237
Deferred compensation	7,895	7,110
Net operating losses	1,150	615
Other expenses not currently deductible	4,617	2,323
Deferred tax assets, gross	39,555	34,365
Valuation allowance	(18,190)	(15,411)
Deferred tax assets, net of valuation allowance	21,365	18,954
Depreciation and amortization	(1,600)	(1,259)
Undistributed foreign earnings	(77)	(77)
Other expenses currently deductible	(1,132)	(425)
Deferred tax liabilities	(2,809)	(1,761)
Net deferred tax assets	$ 18,556	$ 17,193

Note 12 - Income Taxes - Unreco

Note 12 - Income Taxes - Unrecognized Tax Benefits Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Balance	$ 25,407	$ 20,491	$ 16,272
Increase for tax position of prior year		1,589	1,474
Increase for tax position of current year	9,782	4,663	2,957
Decrease due to lapse of statute of limitation	(223)	(776)	(212)
Decrease due to settlement with tax authorities	(560)	(560)
Decrease for tax position of prior year	(907)
Balance	$ 33,499	$ 25,407	$ 20,491

Note 13 - Commitments and Con_3

Note 13 - Commitments and Contingencies (Details Textual) $ in Millions	Dec. 31, 2020USD ($)
Purchase Obligation, Total	$ 211.5

Note 13 - Commitments and Con_4

Note 13 - Commitments and Contingencies - Changes in Warranty Reserve (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Balance	$ 1,139	$ 4,564	$ 2,416
Warranty provision for product sales	7,584	891	6,586
Settlements made	(843)	(2,768)	(1,402)
Unused warranty provision	(985)	(1,548)	(3,036)
Balance	$ 6,895	$ 1,139	$ 4,564

Note 14 - Employee 401(k) Plan

Note 14 - Employee 401(k) Plan (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 0	$ 0	$ 0

Note 15 - Significant Custome_3

Note 15 - Significant Customers - Customers Concentration Summary (Details) - Customer Concentration Risk [Member]	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue Benchmark [Member]
Concentration Risk, Percentage	81.00%	83.00%	87.00%
Revenue Benchmark [Member] | Distributor A [Member]
Concentration Risk, Percentage	24.00%	23.00%	22.00%
Revenue Benchmark [Member] | Distributor B [Member]
Concentration Risk, Percentage	11.00%		10.00%
Accounts Receivable [Member] | Distributor A [Member]
Concentration Risk, Percentage	24.00%	24.00%
Accounts Receivable [Member] | Distributor B [Member]
Concentration Risk, Percentage	21.00%	11.00%
Accounts Receivable [Member] | Value Added Reseller A [Member]
Concentration Risk, Percentage	13.00%	13.00%
Accounts Receivable [Member] | Customer A (Direct) [Member]
Concentration Risk, Percentage	10.00%

Note 16 - Segment and Geograp_3

Note 16 - Segment and Geographic Information (Details Textual)	12 Months Ended
	Dec. 31, 2020
Number of Reportable Segments	1

Note 16 - Segment and Geograp_4

Note 16 - Segment and Geographic Information - Revenue by Region (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue	$ 844,452	$ 627,921	$ 582,382
CHINA
Revenue	516,519	382,740	334,726
TAIWAN, PROVINCE OF CHINA
Revenue	109,256	73,801	75,307
Europe [Member]
Revenue	56,329	49,467	49,484
KOREA, REPUBLIC OF
Revenue	64,093	43,900	41,238
South East Asia [Member]
Revenue	42,403	32,031	36,495
JAPAN
Revenue	35,461	27,812	26,853
UNITED STATES
Revenue	20,098	17,836	17,621
Other Region [Member]
Revenue	$ 293	$ 334	$ 658

Note 16 - Segment and Geograp_5

Note 16 - Segment and Geographic Information - Revenue by Product Family (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue	$ 844,452	$ 627,921	$ 582,382
DC To DC Products [Member]
Revenue	800,478	589,651	537,512
Lighting Control Products [Member]
Revenue	$ 43,974	$ 38,270	$ 44,870

Note 16 - Segment and Geograp_6

Note 16 - Segment and Geographic Information - Long Lived Assets by Geographic Region (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Long lived assets by region	$ 281,528	$ 228,315	$ 150,001
CHINA
Long lived assets by region	151,752	113,888	93,096
UNITED STATES
Long lived assets by region	101,768	94,671	39,054
TAIWAN, PROVINCE OF CHINA
Long lived assets by region	18,797	17,652	16,972
Other Region [Member]
Long lived assets by region	$ 9,211	$ 2,104	$ 879

Note 17 - Accumulated Other C_3

Note 17 - Accumulated Other Comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Balance	$ 773,491	$ 640,093
Balance	966,587	773,491
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Balance	135	(1,638)
Other comprehensive income (loss) before reclassifications	2,878	1,977
Amounts reclassified from accumulated other comprehensive income (loss)	(1,087)	(1)
Tax effect	(325)	(203)
Net current period other comprehensive income (loss)	1,466	1,773
Balance	1,601	135
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Balance	(5,611)	(3,905)
Other comprehensive income (loss) before reclassifications	14,150	(1,706)
Amounts reclassified from accumulated other comprehensive income (loss)	0	0
Tax effect	0	0
Net current period other comprehensive income (loss)	14,150	(1,706)
Balance	8,539	(5,611)
AOCI Attributable to Parent [Member]
Balance	(5,476)	(5,543)
Other comprehensive income (loss) before reclassifications	17,028	271
Amounts reclassified from accumulated other comprehensive income (loss)	(1,087)	(1)
Tax effect	(325)	(203)
Net current period other comprehensive income (loss)	15,616	67
Balance	$ 10,140	$ (5,476)

Note 18 - Subsequent Event (Det

Note 18 - Subsequent Event (Details Textual) - $ / shares	1 Months Ended	12 Months Ended
	Feb. 28, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Common Stock, Dividends, Per Share, Declared (in dollars per share)		$ 2	$ 1.60	$ 1.20
Quarterly Cash Dividends [Member]
Common Stock, Dividends, Per Share, Declared (in dollars per share)		$ 0.50
Quarterly Cash Dividends [Member] | Subsequent Event [Member]
Common Stock, Dividends, Per Share, Declared (in dollars per share)	$ 0.60