Universal Display (OLED) 10-K 20 Feb 20 2019 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2019	Feb. 18, 2020	Jun. 28, 2019
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Trading Symbol	OLED
Entity Registrant Name	UNIVERSAL DISPLAY CORPORATION
Entity Central Index Key	0001005284
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Shell Company	false
Title of 12(b) Security	Common Stock, $0.01 par value
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	PA
Entity Interactive Data Current	Yes
Entity Small Business	false
Entity Emerging Growth Company	false
Document Annual Report	true
Document Transition Report	false
Entity File Number	1-12031
Entity Tax Identification Number	23-2372688
Entity Address, Address Line One	375 Phillips Boulevard
Entity Address, City or Town	Ewing
Entity Address, State or Province	NJ
Entity Address, Postal Zip Code	08618
City Area Code	609
Local Phone Number	671-0980
Entity Common Stock, Shares Outstanding		47,187,793
Entity Public Float			$ 7,951,407,550
Documents Incorporated by Reference	Portions of the registrant’s Proxy Statement for the 2020 Annual Meeting of Shareholders, which is to be filed with the Securities and Exchange Commission no later than April 29, 2020, are incorporated by reference into Part III of this report.

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
CURRENT ASSETS:
Cash and cash equivalents	$ 131,627	$ 211,022
Short-term investments	514,461	304,323
Accounts receivable	60,452	43,129
Inventory	63,953	70,000
Other current assets	21,946	6,366
Total current assets	792,439	634,840
PROPERTY AND EQUIPMENT, net of accumulated depreciation of $57,276 and $44,943	87,872	69,739
ACQUIRED TECHNOLOGY, net of accumulated amortization of $132,468 and $111,890	90,774	110,951
OTHER INTANGIBLE ASSETS, net of accumulated amortization of $4,768 and $3,384	12,072	13,456
GOODWILL	15,535	15,535
INVESTMENTS	5,000
DEFERRED INCOME TAXES	30,375	24,377
OTHER ASSETS	86,090	64,526
TOTAL ASSETS	1,120,157	933,424
CURRENT LIABILITIES:
Accounts payable	13,296	10,532
Accrued expenses	49,022	36,057
Deferred revenue	97,333	80,782
Other current liabilities	1,857	5,811
Total current liabilities	161,508	133,182
DEFERRED REVENUE	47,529	41,785
RETIREMENT PLAN BENEFIT LIABILITY	51,117	44,055
OTHER LIABILITIES	48,554	23,896
Total liabilities	308,708	242,918
COMMITMENTS AND CONTINGENCIES (Note 16)
SHAREHOLDERS' EQUITY:
Preferred Stock, par value $0.01 per share, 5,000,000 shares authorized, 200,000 shares of Series A Nonconvertible Preferred Stock issued and outstanding (liquidation value of $7.50 per share or $1,500)	2	2
Common Stock, par value $0.01 per share, 200,000,000 shares authorized, 48,852,193 and 48,681,524 shares issued, and 47,486,545 and 47,319,887 shares outstanding at December 31, 2019 and December 31, 2018, respectively	489	487
Additional paid-in capital	620,236	617,334
Retained earnings	249,003	129,552
Accumulated other comprehensive loss	(16,997)	(16,234)
Treasury stock, at cost (1,365,648 and 1,361,637 shares at December 31, 2019 and December 31, 2018, respectively)	(41,284)	(40,635)
Total shareholders’ equity	811,449	690,506
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	$ 1,120,157	$ 933,424

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	$ 57,276,000	$ 44,943,000
Finite-Lived Intangible Assets, Accumulated Amortization	132,468,000	111,890,000
Other Finite-Lived Intangible Assets, Accumulated Amortization	$ 4,768,000	$ 3,384,000
SHAREHOLDERS' EQUITY:
Preferred Stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred Stock, shares authorized ( in shares)	5,000,000	5,000,000
Common Stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common Stock, shares authorized (in shares)	200,000,000	200,000,000
Common Stock, shares issued (in shares)	48,852,193	48,681,524
Common Stock, shares outstanding (in shares)	47,486,545	47,319,887
Treasury Stock
Treasury stock, shares	1,365,648	1,361,637
Series A Nonconvertible Preferred Stock [Member]
Shareholders' Equity A Nonconvertible Preferred Stock
Preferred Stock, shares issued (in shares)	200,000	200,000
Preferred Stock, shares outstanding (in shares)	200,000	200,000
Preferred Stock, liquidation value per share (in dollars per share)	$ 7.50	$ 7.50
Preferred Stock, liquidation value	$ 1,500,000	$ 1,500,000

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
REVENUE	$ 405,177	$ 247,414	$ 335,629
COST OF SALES	75,374	53,541	54,698
Gross margin	329,803	193,873	280,931
OPERATING EXPENSES:
Research and development	71,276	53,717	49,144
Selling, general and administrative	59,613	46,999	46,808
Amortization of acquired technology and other intangible assets	21,962	21,962	21,983
Patent costs	6,833	7,464	7,010
Royalty and license expense	11,776	6,996	9,739
Total operating expenses	171,460	137,138	134,684
OPERATING INCOME	158,343	56,735	146,247
Interest income, net	10,795	7,659	3,294
Other income (expense), net	767	(83)	(4)
Interest and other income, net	11,562	7,576	3,290
INCOME BEFORE INCOME TAXES	169,905	64,311	149,537
INCOME TAX EXPENSE	(31,601)	(5,471)	(45,652)
NET INCOME	$ 138,304	$ 58,840	$ 103,885
NET INCOME PER COMMON SHARE:
BASIC	$ 2.92	$ 1.24	$ 2.19
DILUTED	$ 2.92	$ 1.24	$ 2.18
WEIGHTED AVERAGE SHARES USED IN COMPUTING NET INCOME PER COMMON SHARE:
BASIC	46,959,775	46,849,588	46,725,289
DILUTED	46,995,462	46,896,766	46,805,194
CASH DIVIDEND DECLARED PER COMMON SHARE	$ 0.40	$ 0.24	$ 0.12

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement Of Income And Comprehensive Income [Abstract]
NET INCOME	$ 138,304	$ 58,840	$ 103,885
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX:
Unrealized gain (loss) on available-for-sale securities, net of tax of $51, $74 and $7, respectively	181	268	(12)
Employee benefit plan:
Actuarial loss on retirement plan, net of tax of $988, $1,841 and $1,047, respectively	(3,492)	(6,690)	(1,904)
Plan amendment cost, net of tax of none, none and $154, respectively			(280)
Amortization of prior service cost, actuarial loss and plan amendment cost for retirement plan included in net periodic pension costs, net of tax of $713, $457 and $754, respectively	2,523	1,661	1,370
Net change in employee benefit plan	(969)	(5,029)	(814)
Change in cumulative foreign currency translation adjustment	25	(9)	28
TOTAL OTHER COMPREHENSIVE LOSS	(763)	(4,770)	(798)
COMPREHENSIVE INCOME	$ 137,541	$ 54,070	$ 103,087

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement Of Income And Comprehensive Income [Abstract]
Unrealized gain (loss) on available-for-sale securities, tax	$ 51,000	$ 74,000	$ 7,000
Actuarial loss on retirement plan, tax	988,000	1,841,000	1,047,000
Plan amendment cost, tax	0	0	154,000
Amortization of prior service cost and actuarial loss for retirement plan included in net periodic pension costs, tax	$ 713,000	$ 457,000	$ 754,000

CONSOLIDATED STATEMENT OF SHARE

CONSOLIDATED STATEMENT OF SHAREHOLDERS' EQUITY - USD ($)	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Treasury Stock [Member]	Series A Nonconvertible Preferred Stock [Member]Preferred Stock [Member]
BALANCE at Dec. 31, 2016	$ 528,468,000	$ 483,000	$ 604,364,000	$ (25,557,000)	$ (10,666,000)	$ (40,158,000)	$ 2,000
BALANCE (in shares) at Dec. 31, 2016		48,270,990				1,357,863	200,000
Cumulative effect of recording excess tax benefits from share-based payment arrangements	26,450,000			26,450,000
Net income	103,885,000			103,885,000
Other comprehensive income (loss)	(798,000)				(798,000)
Cash dividend	(5,652,000)			(5,652,000)
Exercise of common stock options	38,000		38,000
Exercise of common stock options (in shares)		2,250
Issuance of common stock to employees	12,242,000	$ 3,000	12,239,000
Issuance of common stock to employees (in shares)		265,233
Shares withheld for employee taxes	(9,432,000)	$ (1,000)	(9,431,000)
Shares withheld for employee taxes (in shares)		(109,483)
Issuance of common stock to Board of Directors and Scientific Advisory Board	2,909,000		2,909,000
Issuance of common stock to Board of Directors and Scientific Advisory Board (in shares)		37,314
Issuance of common stock to employees under an ESPP	944,000		944,000
Issuance of common stock to employees under an ESPP (in shares)		9,730
BALANCE at Dec. 31, 2017	659,054,000	$ 485,000	611,063,000	99,126,000	(11,464,000)	$ (40,158,000)	$ 2,000
BALANCE (in shares) at Dec. 31, 2017		48,476,034				1,357,863	200,000
ASC Topic 606 Adoption at Dec. 31, 2017	(17,100,000)			(17,100,000)
ADJUSTED BALANCE at Dec. 31, 2017	641,954,000	$ 485,000	611,063,000	82,026,000	(11,464,000)	$ (40,158,000)	$ 2,000
BALANCE ADJUSTED (in shares) at Dec. 31, 2017		48,476,034				1,357,863	200,000
Net income	58,840,000			58,840,000
Other comprehensive income (loss)	(4,770,000)				(4,770,000)
Cash dividend	(11,314,000)			(11,314,000)
Issuance of common stock to employees	12,139,000	$ 3,000	12,136,000
Issuance of common stock to employees (in shares)		271,068
Shares withheld for employee taxes	(11,620,000)	$ (1,000)	(11,619,000)
Shares withheld for employee taxes (in shares)		(108,113)
Common shares repurchased	$ (477,000)					$ (477,000)
Common shares repurchased (in shares)	3,774					3,774
Issuance of common stock to Board of Directors and Scientific Advisory Board	$ 4,664,000		4,664,000
Issuance of common stock to Board of Directors and Scientific Advisory Board (in shares)		32,232
Issuance of common stock to employees under an ESPP	1,090,000		1,090,000
Issuance of common stock to employees under an ESPP (in shares)		10,303
BALANCE at Dec. 31, 2018	690,506,000	$ 487,000	617,334,000	129,552,000	(16,234,000)	$ (40,635,000)	$ 2,000
BALANCE (in shares) at Dec. 31, 2018		48,681,524				1,361,637	200,000
Net income	138,304,000			138,304,000
Other comprehensive income (loss)	(763,000)				(763,000)
Cash dividend	(18,853,000)			(18,853,000)
Issuance of common stock to employees	15,877,000	$ 2,000	15,875,000
Issuance of common stock to employees (in shares)		247,776
Shares withheld for employee taxes	(15,980,000)		(15,980,000)
Shares withheld for employee taxes (in shares)		(99,099)
Common shares repurchased	$ (649,000)					$ (649,000)
Common shares repurchased (in shares)	4,011					4,011
Issuance of common stock to Board of Directors and Scientific Advisory Board	$ 1,848,000		1,848,000
Issuance of common stock to Board of Directors and Scientific Advisory Board (in shares)		14,500
Issuance of common stock to employees under an ESPP	1,159,000		1,159,000
Issuance of common stock to employees under an ESPP (in shares)		7,492
BALANCE at Dec. 31, 2019	$ 811,449,000	$ 489,000	$ 620,236,000	$ 249,003,000	$ (16,997,000)	$ (41,284,000)	$ 2,000
BALANCE (in shares) at Dec. 31, 2019		48,852,193				1,365,648	200,000

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 138,304	$ 58,840	$ 103,885
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of deferred revenue and recognition of unbilled receivables	(135,368)	(68,905)	(11,122)
Depreciation	12,456	8,612	4,919
Amortization of intangibles	21,962	21,962	21,983
Change in excess inventory reserve	5,938	3,630	0
Amortization of premium and discount on investments, net	(6,643)	(6,131)	(2,871)
Stock-based compensation to employees	16,148	12,432	12,284
Stock-based compensation to Board of Directors and Scientific Advisory Board	1,548	4,364	2,609
Change in earnout liability recorded for Adesis acquisition			519
Deferred income tax (benefit) expense	(5,776)	(12,814)	24,396
Retirement plan expense	5,818	4,466	4,351
Decrease (increase) in assets:
Accounts receivable	(17,323)	9,226	(27,361)
Inventory	109	(37,365)	(18,951)
Other current assets	(15,238)	4,860	(3,884)
Deferred income taxes		20,682
Other assets	(13,291)	(63,922)	(297)
Increase (decrease) in liabilities:
Accounts payable and accrued expenses	15,516	1,563	16,420
Other current liabilities	(5,183)	5,761	(1,917)
Deferred revenue	157,321	130,639	8,402
Other liabilities	17,614	23,896
Net cash provided by operating activities	193,912	121,796	133,365
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	(30,059)	(25,391)	(29,803)
Purchase of intangibles	(401)
Purchases of investments	(931,854)	(628,789)	(594,283)
Proceeds from sale of investments	723,600	633,179	498,508
Net cash used in investing activities	(238,714)	(21,001)	(125,578)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock	889	798	734
Repurchase of common stock	(649)	(477)
Proceeds from the exercise of common stock options			38
Payment of withholding taxes related to stock-based compensation to employees	(15,980)	(11,620)	(9,432)
Cash dividends paid	(18,853)	(11,314)	(5,652)
Net cash used in financing activities	(34,593)	(22,613)	(14,312)
(DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	(79,395)	78,182	(6,525)
CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR	211,022	132,840	139,365
CASH AND CASH EQUIVALENTS, END OF YEAR	$ 131,627	$ 211,022	$ 132,840

CONSOLIDATED STATEMENTS OF CA_2

CONSOLIDATED STATEMENTS OF CASH FLOWS Non-Cash Activities - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Other Significant Noncash Transactions [Line Items]
Unrealized gain (loss) on available-for-sale securities	$ 241	$ 342	$ (19)
Net change in accounts payable and accrued expenses related to purchases of property and equipment	(530)	3,490	4,363
Cash paid for income tax	46,602	17,771	23,248
Common Stock Issued to Board of Directors and Scientific Advisory Board that was Earned and Accrued for in Previous Period [Member]
Other Significant Noncash Transactions [Line Items]
Other significant noncash transaction, value of consideration received	$ 300	$ 300	300
Common Stock Issued to Employees that was Earned and Accrued for in Previous Period Net of Shares Withheld for Taxes [Member]
Other Significant Noncash Transactions [Line Items]
Other significant noncash transaction, value of consideration received			$ 174

BUSINESS

BUSINESS	12 Months Ended
	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
BUSINESS	1. BUSINESS: Universal Display Corporation and its subsidiaries (the Company) is a leader in the research, development and commercialization of organic light emitting diode (OLED) technologies and materials for use in display and solid-state lighting applications. OLEDs are thin, lightweight and power-efficient solid-state devices that emit light that can be manufactured on both flexible and rigid substrates, making them highly suitable for use in full-color displays and as lighting products. OLED displays are capturing a growing share of the display market, especially in the mobile phone, television, wearable, tablet, notebook and personal computer, augmented reality (AR), virtual reality (VR) and automotive markets. The Company believes this is because OLEDs offer potential advantages over competing display technologies with respect to power efficiency, contrast ratio, viewing angle, video response time, form factor and manufacturing cost. The Company also believes that OLED lighting products have the potential to replace many existing light sources in the future because of their high-power efficiency, excellent color rendering index, low operating temperature and novel form factor. The Company's technology leadership, intellectual property position, and the Company’s more than 20 years of experience working closely with leading OLED display manufacturers are some of the competitive advantages that should enable the Company to continue to share in the revenues from OLED displays and lighting products as they gain wider acceptance. The Company’s primary business strategy is to (1) develop new OLED materials and sell existing and any new materials to product manufacturers of products for display applications, such as mobile phones, televisions, wearables, tablets, portable media devices, notebook computers, personal computers, and automotive applications, and specialty and general lighting products; and (2) further develop and license the Company’s proprietary OLED technologies to those manufacturers. The Company has established a significant portfolio of proprietary OLED technologies and materials, primarily through internal research and development efforts and acquisitions of patents and patent applications, as well as maintaining long-standing, and establishing new relationships with world-class universities, research institutions and strategic manufacturing partnerships. The Company currently owns, exclusively license or have the sole right to sublicense more than 5,000 patents issued and pending worldwide. The Company manufactures and sells its proprietary OLED materials to customers for evaluation and use in commercial OLED products. The Company also enters into agreements with manufacturers of OLED display and lighting products under which it grants them licenses to practice under the Company’s patents and to use the Company's proprietary know-how. At the same time, the Company works with these and other companies that are evaluating the Company's OLED technologies and materials for possible use in commercial OLED display and lighting products.

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES: Principles of Consolidation The Consolidated Financial Statements include the accounts of Universal Display Corporation and its wholly owned subsidiaries, UDC, Inc., UDC Ireland Limited (UDC Ireland), Universal Display Corporation Hong Kong, Limited, Universal Display Corporation Korea, Y.H., Universal Display Corporation Japan GK, Universal Display Corporation China, Ltd., Adesis, Inc. (Adesis) and UDC Ventures LLC. UDC Ventures LLC was formed on March 1, 2019 as a corporate venture capital entity that will assist in funding companies that are developing innovative products and technologies that may be synergistic to those of the Company. All intercompany transactions and accounts have been eliminated. Management’s Use of Estimates The preparation of financial statements in conformity with U.S. generally accepted accounting principles (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. The estimates made are principally in the areas of revenue recognition including estimates of material unit sales and royalties, the useful life of acquired intangibles, lease liabilities, right-of-use assets, the use and recoverability of inventories, intangibles, investments and income taxes including realization of deferred tax assets, stock-based compensation and retirement benefit plan liabilities. Actual results could differ from those estimates. Cash and Cash Equivalents The Company considers all highly liquid debt instruments purchased with an original maturity (maturity at the purchase date) of three months or less to be cash equivalents. The Company classifies its remaining investments as available-for-sale. These securities are carried at fair market value, with unrealized gains and losses reported in shareholders’ equity. Gains or losses on securities sold are based on the specific identification method. Trade Accounts Receivable Trade accounts receivable are stated at the amount the Company expects to collect and do not bear interest. The Company considers the following factors when determining the collectability of specific customer accounts: customer credit-worthiness, past transaction history with the customer, current economic industry trends, and changes in customer payment terms. The Company’s accounts receivable balance is a result of chemical sales, royalties and license fees. These receivables have historically been paid timely. Due to the nature of the accounts receivable balance, the Company believes there is no significant risk of collection. If the financial condition of the Company’s customers were to deteriorate, adversely affecting their ability to make payments, allowances for doubtful accounts would be required. The allowance for doubtful accounts was $84,000, $77,000 and none at December 31, 2019, 2018 and 2017, respectively. Inventories Inventories consist of raw materials, work-in-process and finished goods, including inventory consigned to customers, and are stated at the lower of cost, determined on a first-in, first-out basis, or net realizable value. Inventory valuation and firm committed purchase order assessments are performed on a quarterly basis and those items that are identified to be obsolete or in excess of forecasted usage are written down to their estimated realizable value. Estimates of realizable value are based upon management’s analyses and assumptions, including, but not limited to, forecasted sales levels by product, expected product lifecycle, product development plans and future demand requirements. A 12-month rolling forecast based on factors, including, but not limited to, production cycles, anticipated product orders, marketing forecasts, backlog, and shipment activities is used in the inventory analysis. If market conditions are less favorable than forecasts or actual demand from customers is lower than estimates, additional inventory write-downs may be required. If demand is higher than expected, inventories that had previously been written down may be sold. Property and Equipment Property and equipment are stated at cost and depreciated on a straight-line basis over the estimated useful life of 30 years for building, 15 years for building improvements, and three to seven years for office and lab equipment and furniture and fixtures. Repair and maintenance costs are charged to expense as incurred. Additions and betterments are capitalized. Major renewals and improvements are capitalized and minor replacements, maintenance, and repairs are charged to current operations as incurred. Upon retirement or disposal of assets, the cost and related accumulated depreciation are removed from the Consolidated Balance Sheets and any gain or loss is reflected in other operating expenses. Certain costs of computer software obtained for internal use are capitalized and amortized on a straight-line basis over three years. Costs for maintenance and training, as well as the cost of software that does not add functionality to an existing system, are expensed as incurred. Impairment of Long-Lived Assets Company management continually evaluates whether events or changes in circumstances might indicate that the remaining estimated useful life of long-lived assets may warrant revision, or that the remaining balance may not be recoverable. When factors indicate that long-lived assets should be evaluated for possible impairment, the Company uses an estimate of the related undiscounted cash flows in measuring whether the long-lived asset should be written down to fair value. Measurement of the amount of impairment would be based on generally accepted valuation methodologies, as deemed appropriate. As of December 31, 2019, Company management believed that no revision to the remaining useful lives or write-down of the Company’s long-lived assets was required, and similarly, no such revisions were required for the years ended December 31, 2018 or 2017. Goodwill and Purchased Intangible Assets Goodwill is tested for impairment in the fourth fiscal quarter and, when specific circumstances dictate, between annual tests. Company management first assesses qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount as a basis for determining whether a quantitative goodwill impairment test is necessary. If it is concluded it is more likely than not that the fair value of a reporting unit exceeds its carrying amount, then a quantitative impairment assessment is not necessary. If it is determined that goodwill has been impaired, then its carrying value is written down to fair value. The goodwill impairment test involves a two-step process. The first step, identifying a potential impairment, compares the fair value of a reporting unit with its carrying amount, including goodwill. If the carrying value of the reporting unit exceeds its fair value, the second step would need to be conducted; otherwise, no further steps are necessary as no potential impairment exists. If necessary, the second step to measure the impairment loss would be to compare the implied fair value of the reporting unit goodwill with the carrying amount of that goodwill. Any excess of the reporting unit goodwill carrying value over the respective implied fair value is recognized as an impairment loss. The Company performed its annual impairment assessment as of December 31, 2019 utilizing a qualitative evaluation and concluded that it was more likely than not that the fair value of Adesis is great er than its carrying value. Company management believes it has made reasonable estimates and assumptions to calculate the fa ir value of the reporting unit. Future impairment tests will continue to be performed annually in the fiscal fourth quarter, or sooner if a triggering event occurs. As o f December 31, 201 9 , no indications of impairment exist ed . Purchased intangible assets with finite lives are carried at cost, less accumulated amortization. Amortization is computed over the estimated useful lives of the respective assets. Fair Value of Financial Instruments The carrying values of accounts receivable, other current assets, and accounts payable approximate fair value in the accompanying financial statements due to the short-term nature of those instruments. The Company’s other financial instruments, which include cash equivalents and investments, are carried at fair value. Fair Value Measurements Fair value is defined as an exit price, representing the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants based on the highest and best use of the asset or liability. The Company uses valuation techniques to measure fair value that maximize the use of observable inputs and minimize the use of unobservable inputs. Observable inputs are inputs that market participants would use in pricing the asset or liability and are based on market data obtained from sources independent of the Company. Unobservable inputs reflect assumptions market participants would use in pricing the asset or liability based on the best information available in the circumstances Minority Equity Investments The Company accounts for minority equity investments in companies that are not accounted for under the equity method as equity securities without readily determinable fair values. The fair values of these securities is based on original cost less impairments, if any, plus or minus changes resulting from observable price changes in orderly transactions for the identical or similar investment of the same issuer. Under this method, the share of income or loss of such companies is not included in the Consolidated Statements of Income. The carrying value of these investments is included in investments on the Consolidated Balance Sheets. The Company’s policy is to recognize an impairment in the value of its minority equity investments when clear evidence of an impairment exists. Factors considered in the assessment include a significant adverse change in the regulatory, economic, or technological environment, the completion of new equity financing that may indicate a decrease in value, the failure to complete new equity financing arrangements after seeking to raise additional funds, or the commencement of proceedings under which the assets of the business may be placed in receivership or liquidated to satisfy claims of debt and equity stakeholders. Leases The Company is a lessee in operating leases primarily incurred to facilitate the expansion of manufacturing, research and development, and selling, general and administrative activities. As discussed in Note 8, effective January 1, 2019, the Company accounts for leases in accordance with Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) Topic 842, Leases Key estimates and judgements include how the Company determines the discount rate used to discount the unpaid lease payments to present value and the lease term. The Company monitors for events or changes in circumstances that could potentially require recognizing an impairment loss. Revenue Recognition and Deferred Revenue Material sales relate to the Company’s sale of its OLED materials for incorporation into its customers’ commercial OLED products or for their OLED development and evaluation activities. Revenue associated with material sales is generally recognized at the time title passes, which is typically at the time of shipment or at the time of delivery, depending upon the contractual agreement between the parties. Revenue may be recognized after control of the material passes in the event the transaction price includes variable consideration. For example , a customer may be provided an extended opportunity to stock materials prior to use in mass production and given a general right of return not conditioned on breaches of warranties associated with the specific product. In such circumstances, revenue will be recognized at the earlier of the expiration of the customer’s general right of return or once it becomes unlikely that the customer will exercise its right of return . The rights and benefits to the Company’s OLED technologies are conveyed to the customer through technology license agreements and material supply agreements. The Company believes that the licenses and materials sold under these combined agreements are not distinct from each other for financial reporting purposes and as such, are accounted for as a single performance obligation. Accordingly, total contract consideration, including material, license and royalty fees, is estimated and recognized over the contract term based on material units sold at the estimated per unit fee over the life of the contract. Various estimates are relied upon to recognize revenue. The Company estimates total material units to be purchased by its customers over the contract term based on historical trends, industry estimates and its forecast process. Management uses the expected value method to estimate the material per unit fee. Additionally, management estimates the total sales-based royalties based on the estimated net sales revenue of its customers over the contract term. Contract research services revenue is revenue earned by Adesis by providing chemical materials synthesis research, development and commercialization for non-OLED applications on a contractual basis. These services range from intermediates for structure-activity relationship studies, reference agents and building blocks for combinatorial synthesis, re-synthesis of key intermediates, specialty organic chemistry needs, and selective toll manufacturing. These services are provided to third-party pharmaceutical and life sciences firms and other technology firms at fixed costs or on an annual contract basis. Revenue is recognized as services are performed with billing schedules and payment terms negotiated on a contract-by-contract basis. Payments received in excess of revenue recognized are recorded as deferred revenue. In other cases, services may be provided and revenue is recognized before the customer is invoiced. In these cases, revenue recognized will exceed amounts billed and the difference, representing amounts which are currently unbillable to the customer pursuant to contractual terms, is recorded as an unbilled receivable. Technology development and support revenue is revenue earned from development and technology evaluation agreements and commercialization assistance fees, along with, to a minimal extent, government contracts. Relating to the Company’s government contracts, the Company may receive reimbursements by government entities for all or a portion of the research and development costs the Company incurs. Revenues are recognized as services are performed, proportionally as research and development costs are incurred, or as defined milestones are achieved. In 2018, the Company entered into a commercial license agreement with Samsung Display Co., Ltd. (SDC). This agreement, which covers the manufacture and sale of specified OLED display materials, was effective as of January 1, 2018 and lasts through the end of 2022 with an additional two-year At the same time the Company entered into the current patent license agreement with SDC, the Company also entered into a new supplemental material purchase agreement with SDC. Under the supplemental material purchase agreement, SDC agrees to purchase from the Company a minimum amount of phosphorescent emitter materials for use in the manufacture of licensed products. This minimum commitment is subject to SDC’s requirements for phosphorescent emitter materials and the Company’s ability to meet these requirements over the term of the supplemental agreement. In 2015, the Company entered into an OLED patent license agreement and an OLED commercial supply agreement with LG Display Co., Ltd. (LG Display) which were effective as of January 1, 2015 and superseded the existing 2007 commercial supply agreement between the parties. The new agreements have a term that is set to expire by the end of 2022. The patent license agreement provides LG Display a non-exclusive, royalty bearing portfolio license to make and sell OLED displays under the Company's patent portfolio. The patent license calls for license fees, prepaid royalties and running royalties on licensed products. The agreements include customary provisions relating to warranties, indemnities, confidentiality, assignability and business terms. The agreements provide for certain other minimum obligations relating to the volume of material sales anticipated over the life of the agreements as well as minimum royalty revenue to be generated under the patent license agreement. The Company generates revenue under these agreements that are predominantly tied to LG Display’s sales of OLED licensed products. The OLED commercial supply agreement provides for the sale of materials for use by LG Display, which may include phosphorescent emitters and host materials. In 2016, the Company entered into long-term, multi-year OLED patent license and material purchase agreements with Tianma Micro-electronics Co., Ltd. (Tianma). Under the license agreement, the Company has granted Tianma non-exclusive license rights under various patents owned or controlled by the Company to manufacture and sell OLED display products. The license agreement calls for license fees and running royalties on licensed products. Additionally, the Company suppl ies phosphorescent OLED materials to Tianma for use in its licensed products. In 2017, the Company entered into long-term, multi-year agreements with BOE Technology Group Co., Ltd. (BOE). Under these agreements, the Company has granted BOE non-exclusive license rights under various patents owned or controlled by the Company to manufacture and sell OLED display products. The Company supplies phosphorescent OLED materials to BOE for use in its licensed products. In 2018, the Company entered into long-term, multi-year OLED patent license and material purchase agreements with Visionox Technology, Inc. (Visionox). Under the license agreement, the Company has granted Visionox non-exclusive license rights under various patents owned or controlled by the Company to manufacture and sell OLED display products. The license agreement calls for license fees and running royalties on licensed products. Additionally, the Company supplies phosphorescent OLED materials to Visionox for use in its licensed products. In 2019, the Company entered into an evaluation and commercial supply relationship with Wuhan China Star Optoelectronics Semiconductor Display Technology Co., Ltd. (CSOT). The Company has been collaborating with CSOT in the area of OLED display product design and manufacture and expects to continue to do so. All material sales transactions that are not variable consideration transactions are billed and due within 90 days and substantially all are transacted in U.S. dollars. Cost of Sales Cost of sales consists of labor and material costs associated with the production of materials processed at the Company's manufacturing partners and at the Company's internal manufacturing processing facilities. The Company’s portion of cost of sales also includes depreciation of manufacturing equipment, as well as manufacturing overhead costs and inventory adjustments for excess and obsolete inventory. Research and Development Expenditures for research and development are charged to operations as incurred. Patent Costs Costs associated with patent applications, patent prosecution, patent defense and the maintenance of patents are charged to expense as incurred. Costs to successfully defend a challenge to a patent are capitalized to the extent of an evident increase in the value of the patent. Costs that relate to an unsuccessful outcome are charged to expense. Amortization of Acquired Technology Amortization costs primarily relate to technology acquired from BASF and Fujifilm. These acquisitions were completed in the years ended December 31, 2016 and 2012, respectively. Acquisition costs are being amortized over a period of 10 years Amortization of Other Intangible Assets Other intangible assets from the Adesis acquisition are being amortized over a period of 10 to 15 years. See Note 7 for further discussion. Translation of Foreign Currency Financial Statements and Foreign Currency Transactions The Company's reporting currency is the U.S. dollar. The functional currency for the Company's Ireland subsidiary is also the U.S. dollar and the functional currency for each of the Company's Asia-Pacific foreign subsidiaries is its local currency. The Company translates the amounts included in the Consolidated Statements of Income from its Asia-Pacific foreign subsidiaries into U.S. dollars at weighted-average exchange rates, which the Company believes are representative of the actual exchange rates on the dates of the transactions. The Company's foreign subsidiaries' assets and liabilities are translated into U.S. dollars from the local currency at the actual exchange rates as of the end of each reporting date, and the Company records the resulting foreign exchange translation adjustments in the Consolidated Balance Sheets as a component of accumulated other comprehensive loss. The overall effect of the translation of foreign currency and foreign currency transactions to date has been insignificant. Income Taxes Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. The Company recognizes the effect of income tax positions only if those positions are more likely than not of being sustained. Recognized income tax positions are measured at the largest amount of which the likelihood of realization is greater than 50%. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. The Company records interest and penalties, if any, related to unrecognized tax benefits as a component of tax expense. Share-Based Payment Awards The Company recognizes in the Consolidated Statements of Income the grant-date fair value of equity based awards such as shares issued under employee stock purchase plans, restricted stock awards, restricted stock units and performance unit awards issued to employees and directors. The grant-date fair value of stock awards is based on the closing price of the stock on the date of grant. The fair value of share-based awards is recognized as compensation expense on a straight-line basis over the requisite service period, net of forfeitures. The Company issues new shares upon the respective grant, exercise or vesting of the share-based payment awards, as applicable. Performance unit awards are subject to either a performance-based or market-based vesting requirement. For performance-based vesting, the grant-date fair value of the award, based on fair value of the Company's common stock, is recognized over the service period, based on an assessment of the likelihood that the applicable performance goals will be achieved and compensation expense is periodically adjusted based on actual and expected performance. Compensation expense for performance unit awards with market-based vesting is calculated based on the estimated fair value as of the grant date utilizing a Monte Carlo simulation model and is recognized over the service period on a straight-line basis. Recent Accounting Pronouncements In February 2016, the FASB issued Accounting Standards Update (ASU) No. 2016-02, Leases (Topic 842) In January 2017, the FASB issued ASU No. 2017-04, Intangibles – Goodwill and Other (Topic 350): Simplifying the Test of Goodwill Impairment In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments: Credit Losses (Topic 326)

CASH, CASH EQUIVALENTS AND INVE

CASH, CASH EQUIVALENTS AND INVESTMENTS	12 Months Ended
	Dec. 31, 2019
Cash And Cash Equivalents [Abstract]
CASH, CASH EQUIVALENTS AND INVESTMENTS	3 . CASH, CASH EQUIVALENTS AND INVESTMENTS: The Company’s portfolio of fixed income securities consists of term bank certificates of deposit, U.S. Government and corporate bonds. The Company considers all highly liquid debt instruments purchased with an original maturity (maturity at the purchase date) of three months or less to be cash equivalents. The Company classifies its remaining debt security investments as available-for-sale. These debt securities are carried at fair market value, with unrealized gains and losses reported in shareholders’ equity. Gains or losses on securities sold are based on the specific identification method. Cash and Cash Equivalents The following table provides details regarding the Company’s portfolio of cash and cash equivalents (in thousands): Amortized Unrealized Aggregate Cash and Cash Equivalents Classification Cost Gains (Losses) Market Value December 31, 2019 Cash accounts in banking institutions $ 119,272 $ — $ — $ 119,272 Money market accounts 12,355 — — 12,355 U.S. Government bonds — — — — $ 131,627 $ — $ — $ 131,627 December 31, 2018 Cash accounts in banking institutions $ 71,217 $ — $ — $ 71,217 Money market accounts 11,014 — — 11,014 U.S. Government bonds 128,782 9 — 128,791 $ 211,013 $ 9 $ — $ 211,022 Short-term Investments The following table provides details regarding the Company’s portfolio of short-term investments (in thousands): Amortized Unrealized Aggregate Short-term Investments Classification Cost Gains (Losses) Market Value December 31, 2019 Certificates of deposit $ 700 $ — $ — $ 700 U.S. Government bonds 513,577 190 (6 ) 513,761 $ 514,277 $ 190 $ (6 ) $ 514,461 December 31, 2018 Certificates of deposit $ 500 $ — $ (1 ) $ 499 Corporate Bonds 114,678 1 (19 ) 114,660 U.S. Government bonds 189,202 5 (43 ) 189,164 $ 304,380 $ 6 $ (63 ) $ 304,323 Minority Investments The Company’s portfolio of minority investments consists of investments in privately held early stage companies primarily motivated to gain early access to new technology and are passive in nature in that the Company does not obtain representation on the board of directors of the companies in which it invests. As of December 31, 2019, the Company had one minority investment with a carrying value of $5.0 million accounted for as an equity security without a readily determinable fair value.

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	4 . FAIR VALUE MEASUREMENTS: The following table provides the assets and liabilities carried at fair value measured on a recurring basis as of December 31, 2019 (in thousands): Fair Value Measurements, Using Total Carrying Value as of December 31, 2019 Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents $ 12,355 $ 12,355 $ — $ — Short-term investments 514,461 514,461 — — The following table provides the assets and liabilities carried at fair value measured on a recurring basis as of December 31, 2018 (in thousands): Fair Value Measurements, Using Total Carrying Value as of December 31, 2018 Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents $ 139,805 $ 139,805 $ — $ — Short-term investments 304,323 304,323 — — Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities. Level 2 inputs are quoted prices for similar assets and liabilities in active markets or inputs that are observable for the asset or liability, either directly or indirectly through market corroboration, for substantially the full term of the financial instrument. Level 3 inputs are unobservable inputs based on management’s own assumptions used to measure assets and liabilities at fair value. A financial asset’s or liability’s classification is determined based on the lowest level input that is significant to the fair value measurement. Changes in fair value of the debt investments are recorded as unrealized gains and losses in other comprehensive loss. If a decline in fair value of an investment is deemed to be other than temporary, the cost of the Company’s investment will be written down by the amount of the other-than-temporary impairment with a resulting charge to net income. There were no other-than-temporary impairments of investments as of December 31, 2019 or December 31, 2018.

INVENTORY

INVENTORY	12 Months Ended
	Dec. 31, 2019
Inventory Disclosure [Abstract]
INVENTORY	5 . INVENTORY: Inventory consisted of the following (in thousands): December 31, 2019 2018 Raw materials $ 25,920 $ 31,203 Work-in-process 7,987 781 Finished goods 30,046 38,016 Inventory $ 63,953 $ 70,000 The Company recorded an increase in inventory reserve of $5.9 million and $3.6 million for the years ended December 31, 2019 and 2018, respectively, due to excess inventory levels in certain products. No increase in inventory reserve was recorded for the year ended December 31, 2017.

PROPERTY AND EQUIPMENT

PROPERTY AND EQUIPMENT	12 Months Ended
	Dec. 31, 2019
Property Plant And Equipment [Abstract]
PROPERTY AND EQUIPMENT	6 . PROPERTY AND EQUIPMENT: Property and equipment consist of the following (in thousands): December 31, 2019 2018 Land $ 2,642 $ 1,006 Building and improvements 47,994 39,285 Office and lab equipment 74,726 55,333 Furniture, fixtures and computer related assets 7,592 6,941 Construction-in-progress 12,194 12,117 145,148 114,682 Less: Accumulated depreciation (57,276 ) (44,943 ) Property and equipment, net $ 87,872 $ 69,739 Depreciation expense was $12.5 million, $8.6 million and $4.9 million for the years ended December 31, 2019, 2018 and 2017, respectively. During the year ended December 31, 2019, the Company purchased property in Ewing, New Jersey, adjacent to its headquarters, as part of its plan to expand operations. The new facilities added approximately 88,000 square feet at a cost of $8.2 million and will allow for the expansion of research and development activities, manufacturing logistics and other corporate functions.

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS	12 Months Ended
	Dec. 31, 2019
Finite Lived Intangible Assets Net [Abstract]
GOODWILL AND INTANGIBLE ASSETS	7 . GOODWILL AND INTANGIBLE ASSETS: The Company monitors the recoverability of goodwill annually or whenever events or changes in circumstances indicate the carrying value may not be recoverable. Purchased intangible assets subject to amortization consist primarily of acquired technology and other intangible assets that include trade names, customer relationships and internally developed IP processes. Acquired Technology Acquired technology consists of acquired license rights for patents and know-how obtained from PD-LD, Inc., Motorola, BASF SE (BASF) and Fujifilm. These intangible assets consist of the following (in thousands): December 31, 2019 2018 PD-LD, Inc. $ 1,481 $ 1,481 Motorola 15,909 15,909 BASF 95,989 95,989 Fujifilm 109,462 109,462 Other 401 — 223,242 222,841 Less: Accumulated amortization (132,468 ) (111,890 ) Acquired technology, net $ 90,774 $ 110,951 Amortization expense related to acquired technology was $20.6 million for all years ended December 31, 2019, 2018 and 2017. Amortization expense is included in amortization of acquired technology and other intangible assets expense line item on the Consolidated Statements of Income and is expected to be $20.6 million in each of the years ending December 31, 2020 through 2021, $15.8 million in the year ending December 31, 2022, $9.7 million in the year ending December 31, 2023, $9.6 million in the year ending December 31, 2024 and $14.5 million thereafter. Fujifilm Patent Acquisition On July 23, 2012, the Company entered into a Patent Sale Agreement with Fujifilm. Under the agreement, Fujifilm sold more than 1,200 OLED-related patents and patent applications in exchange for a cash payment of $105.0 million, plus costs incurred in connection with the purchase. The agreement contains customary representations and warranties and covenants, including respective covenants not to sue by both parties thereto. The agreement permitted the Company to assign all of its rights and obligations under the agreement to its affiliates, and the Company assigned, prior to the consummation of the transactions contemplated by the agreement, its rights and obligations to UDC Ireland, a wholly-owned subsidiary of the Company formed under the laws of the Republic of Ireland. The transactions contemplated by the agreement were consummated on July 26, 2012. The Company recorded the $105.0 million plus $4.5 million of purchase costs as acquired technology, which is being amortized over a period of 10 years. BASF Patent Acquisition On June 28, 2016, UDC Ireland entered into and consummated an IP Transfer Agreement with BASF. Under the IP Transfer Agreement, BASF sold to UDC Ireland all of its rights, title and interest to certain of its owned and co-owned intellectual property rights relating to the composition of, development, manufacture and use of OLED materials, including OLED lighting and display stack technology, as well as certain tangible assets. The intellectual property includes knowhow and more than 500 issued and pending patents in the area of phosphorescent materials and technologies. These assets were acquired in exchange for a cash payment of €86.8 million ($95.8 million). In addition, UDC Ireland also took on certain rights and obligations under three joint research and development agreements to which BASF was a party. The IP Transfer Agreement also contains customary representations, warranties and covenants of the parties. UDC Ireland recorded the payment of €86.8 million ($95.8 million) and acquisition costs incurred of $217,000 as acquired technology, which is being amortized over a period of 10 years. Other Intangible Assets As a result of the Adesis acquisition in June 2016, the Company recorded $16.8 million of other intangible assets, including $10.5 million assigned to customer relationships with a weighted average life of 11.5 years, $4.8 million of internally developed IP, processes and recipes with a weighted average life of 15 years, and $1.5 million assigned to trade name and trademarks with a weighted average life of 10 years. At December 31, 2019, these other intangible assets consist of the following (in thousands): December 31, 2019 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Customer relationships $ 10,520 $ (3,142 ) $ 7,378 Developed IP, processes and recipes 4,820 (1,108 ) 3,712 Trade name/Trademarks 1,500 (518 ) 982 Total identifiable other intangible assets $ 16,840 $ (4,768 ) $ 12,072 Amortization expense related to other intangible assets was $1.4 million for all years ended December 31, 2019, 2018, and 2017. Amortization expense is included in amortization of acquired technology and other intangible assets expense line item on the Consolidated Statements of Income and is expected to be $1.4 million for each of the next five fiscal years (2020 - 2024) and $5.1 million thereafter. Goodwill As a result of the Adesis acquisition, the Company recorded $15.5 million of goodwill. The Company performs its annual assessment of goodwill during the fourth quarter of the fiscal year unless events suggest an impairment may have been incurred in an interim period. Application of the goodwill impairment test requires the exercise of judgment, including the determination of the fair value of each reporting unit. The Company estimates the fair value of reporting units using an income approach based on the present value of estimated future cash flows. As part of the annual assessment of goodwill completed during the fourth quarter ended December 31, 2019, there were no significant indicators to conclude that an impairment of the goodwill associated with the acquisition of Adesis had occurred.

LEASES

LEASES	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
LEASES	8. LEASES: The Company has entered into operating leases to facilitate the expansion of its manufacturing, research and development, and selling, general and administrative activities. For purposes of calculating operating lease liabilities, lease terms may be deemed to include options to extend or terminate the lease when those events are reasonably certain to occur. The interest rate implicit in lease contracts is typically not readily determinable and as such the Company uses the appropriate incremental borrowing rate based on information available at the lease commencement date in determining the present value of the lease payments. The Company used the incremental borrowing rate on January 1, 2019 for operating leases that commenced prior to that date. Current lease agreements do not contain any residual value guarantees or material restrictive covenants. As of December 31, 2019, the Company did not have any finance leases and no additional operating leases that have not yet commenced. As stated in Note 2, effective January 1, 2019, the Company adopted Topic 842 using the modified retrospective transition method. As such, the Company did not restate financial statement or lease disclosure data for periods prior to January 1, 2019, which was prepared in accordance with ASC Topic 840, Leases The following table presents the Company’s operating lease cost and supplemental cash flow information related to the Company’s operating leases (in thousands): Year Ended December 31, 2019 Operating lease cost $ 1,855 Non-cash activity: Right-of-use assets obtained in exchange for lease obligations $ 9,776 As of December 31, 2019, current operating leases had remaining terms between one and nine years with options to extend the lease terms and the Company had operating lease right-of-use assets of $8.5 million, current operating lease liabilities of $1.6 million and long-term operating lease liabilities of $6.9 million. Operating lease cost was $ 1.7 million and $ 972,000 for the years ended December 31, 2018 and 2017, respectively. The following table presents weighted average assumptions used to compute the Company’s right-of-use assets and lease liabilities: December 31, 2019 Weighted average remaining lease term (in years) 7.4 Weighted average discount rate 5.5 % Undiscounted future minimum lease payments as of December 31, 2019, by year and in the aggregate, having non-cancelable lease terms in excess of one year were as follows (in thousands): Maturities of Operating Lease Liabilities 2020 $ 1,958 2021 1,278 2022 1,209 2023 1,070 2024 1,007 Thereafter 3,825 Total lease payments 10,347 Less imputed interest (1,865 ) Present value of lease payments $ 8,482 Future minimum lease payments as of December 31, 2018, by year and in the aggregate, having non-cancelable lease terms in excess of one year were expected to be as follows: Total Minimum Lease Payments 2019 $ 1,652 2020 1,512 2021 833 2022 833 2023 833 Thereafter 4,721 Total lease payments $ 10,384

ACCRUED EXPENSES

ACCRUED EXPENSES	12 Months Ended
	Dec. 31, 2019
Payables And Accruals [Abstract]
ACCRUED EXPENSES	9. ACCRUED EXPENSES: Accrued expenses consist of the following (in thousands): December 31, 2019 2018 Compensation $ 30,295 $ 13,803 Royalties 11,776 6,996 Research and development agreements 3,052 3,572 Consulting 471 527 Professional Fees 268 655 Other 3,160 10,504 Accrued Expenses $ 49,022 $ 36,057

RESEARCH AND LICENSE AGREEMENTS

RESEARCH AND LICENSE AGREEMENTS WITH PRINCETON UNIVERSITY, UNIVERSITY OF SOUTHERN CALIFORNIA AND THE UNIVERSITY OF MICHIGAN	12 Months Ended
	Dec. 31, 2019
Research And Development [Abstract]
RESEARCH AND LICENSE AGREEMENTS WITH PRINCETON UNIVERSITY, UNIVERSITY OF SOUTHERN CALIFORNIA AND THE UNIVERSITY OF MICHIGAN	10. RESEARCH AND LICENSE AGREEMENTS WITH PRINCETON UNIVERSITY, UNIVERSITY OF SOUTHERN CALIFORNIA AND THE UNIVERSITY OF MICHIGAN: The Company funded OLED technology research at Princeton University and, on a subcontractor basis, at the University of Southern California for 10 years under a Research Agreement executed with Princeton University in August 1997 (the 1997 Research Agreement). The principal investigator conducting work under the 1997 Research Agreement transferred to the University of Michigan in January 2006. Following this transfer, the 1997 Research Agreement was allowed to expire on July 31, 2007. As a result of the transfer, the Company entered into a new Sponsored Research Agreement with the University of Southern California to sponsor OLED technology research and, on a subcontractor basis, with the University of Michigan. This new Sponsored Research Agreement (as amended, the 2006 Research Agreement) was effective as of May 1, 2006 and had an original term of three years. On May 1, 2009, the Company amended the 2006 Research Agreement to extend the term of the agreement for an additional four years. The 2006 Research Agreement superseded the 1997 Research Agreement with respect to all work being performed at the University of Southern California and the University of Michigan. Payments under the 2006 Research Agreement were made to the University of Southern California on a quarterly basis as actual expenses were incurred. The Company incurred a total of $5.0 million in research and development expense for work performed under the 2006 Research Agreement, which ended on April 30, 2013. Effective June 1, 2013, the Company amended the 2006 Research Agreement again to extend the term of the agreement for an additional four years. The Company incurred a total of $4.6 million in research and development expense for work performed under the 2006 Research Agreement during the extended term. Effective May 1, 2017, the Company amended the 2006 Research Agreement once again to extend the term of the agreement for an additional three years. As of December 31, 2019, in connection with this amendment, the Company was obligated to pay the University of Southern California up to $1.8 million for work to be performed during the remaining extended term, which expires April 30, 2020. From May 1, 2017 through December 31, 2019, the Company incurred $2.6 million in research and development expense for work performed under the 2006 Research Agreement. In connection with entering into the 2006 Research Agreement, the Company amended the 1997 Amended License Agreement to include the University of Michigan as a party to that agreement effective as of January 1, 2006. Under this amendment, Princeton University, the University of Southern California and the University of Michigan have granted the Company a worldwide exclusive license, with rights to sublicense, to make, have made, use, lease and/or sell products and to practice processes based on patent applications and issued patents arising out of work performed under the 2006 Research Agreement. The financial terms of the 1997 Amended License Agreement were not impacted by this amendment. On October 9, 1997, the Company, Princeton University and the University of Southern California entered into an Amended License Agreement (as amended, the 1997 Amended License Agreement) under which Princeton University and the University of Southern California granted the Company worldwide, exclusive license rights, with rights to sublicense, to make, have made, use, lease and/or sell products and to practice processes based on patent applications and issued patents arising out of work performed by Princeton University and the University of Southern California under the 1997 Research Agreement. Under this 1997 Amended License Agreement, the Company is required to pay Princeton University royalties for licensed products sold by the Company or its sublicensees. For licensed products sold by the Company, the Company is required to pay Princeton University 3% of the net sales price of these products. For licensed products sold by the Company’s sublicensees, the Company is required to pay Princeton 3% of the revenues received by the Company from these sublicensees. These royalty rates are subject to renegotiation for products not reasonably conceivable as arising out of the 1997 Research Agreement if Princeton University reasonably determines that the royalty rates payable with respect to these products are not fair and competitive. The Company is obligated, under the 1997 Amended License Agreement, to pay to Princeton University minimum annual royalties. The minimum royalty payment is $100,000 per year. The Company recorded royalty expense in connection with this agreement of $11.8 million, $7.0 million and $9.7 million for the years ended December 31, 2019, 2018, and 2017, respectively. The Company also is required, under the 1997 Amended License Agreement, to use commercially reasonable efforts to bring the licensed OLED technology to market. However, this requirement is deemed satisfied if the Company invests a minimum of $800,000 per year in research, development, commercialization or patenting efforts respecting the patent rights licensed to the Company.

EQUITY AND CASH COMPENSATION UN

EQUITY AND CASH COMPENSATION UNDER THE PPG AGREEMENTS	12 Months Ended
	Dec. 31, 2019
Long Term Commitment Excluding Unconditional Purchase Obligation [Abstract]
EQUITY AND CASH COMPENSATION UNDER THE PPG AGREEMENTS	11 . EQUITY AND CASH COMPENSATION UNDER THE PPG AGREEMENTS: On September 22, 2011, the Company entered into an Amended and Restated OLED Materials Supply and Service Agreement with PPG (the New OLED Materials Agreement), which replaced the original OLED Materials Agreement with PPG effective as of October 1, 2011. The term of the New OLED Materials Agreement ran through December 31, 2015 and is automatically renewed for additional one-year terms, unless terminated by the Company by providing prior notice of one year or terminated by PPG by providing prior notice of two years. The agreement was automatically renewed through December 31, 2020. The New OLED Materials Agreement contains provisions that are substantially similar to those of the original OLED Materials Agreement. Under the New OLED Materials Agreement, PPG continues to assist the Company in developing its proprietary OLED materials and supplying the Company with those materials for evaluation purposes and for resale to its customers. Under the New OLED Materials Agreement, the Company compensates PPG on a cost-plus basis for the services provided during each calendar quarter. The Company is required to pay for some of these services in all cash. Up to 50% of the remaining services are payable, at the Company’s sole discretion, in cash or shares of the Company’s common stock, with the balance payable in cash. The actual number of shares of common stock issuable to PPG is determined based on the average closing price for the Company’s common stock during a specified number of days prior to the end of each calendar half-year period ending on March 31 and September 30. If, however, this average closing price is less than $20.00, the Company is required to compensate PPG in cash. No shares were issued for services to PPG for the years ended December 31, 2019, 2018 and 2017. The Company is also required to reimburse PPG for raw materials used for research and development. The Company records the purchases of these raw materials as a current asset until such materials are used for research and development efforts. The Company recorded research and development expense of $1.4 million, $771,000 and $1.7 million for the years ended December 31, 2019, 2018 and 2017, respectively, in relation to the cash portion of the reimbursement of expenses and work performed by PPG, excluding amounts paid for commercial chemicals.

SHAREHOLDERS' EQUITY

SHAREHOLDERS' EQUITY	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
SHAREHOLDERS' EQUITY	12. SHAREHOLDERS' EQUITY: Preferred Stock The Company’s Amended and Restated Articles of Incorporation authorize it to issue up to 5,000,000 shares of $0.01 par value preferred stock with designations, rights and preferences determined from time-to-time by the Company’s Board of Directors. Accordingly, the Company’s Board of Directors is empowered, without shareholder approval, to issue preferred stock with dividend, liquidation, conversion, voting or other rights superior to those of shareholders of the Company’s common stock. In 1995, the Company issued 200,000 shares of Series A Nonconvertible Preferred Stock (Series A) to American Biomimetics Corporation (ABC) pursuant to a certain Technology Transfer Agreement between the Company and ABC. The Series A shares have a liquidation value of $7.50 per share. Series A shareholders, as a single class, have the right to elect two members of the Company’s Board of Directors. This right has never been exercised. Holders of the Series A shares are entitled to one vote per share on matters which shareholders are generally entitled to vote. The Series A shareholders are not entitled to any dividends. As of December 31, 2019, the Company had issued 200,000 shares of preferred stock, all of which were outstanding. Common Stock The Company’s Amended and Restated Articles of Incorporation authorize it to issue up 200,000,000 shares of $0.01 par value common stock. Each share of the Company’s common stock entitles the holder to one vote on all matters to be voted upon by the shareholders. As of December 31, 2019, the Company had issued 48,852,193 shares of common stock, of which 47,486,545 were outstanding. During the years ended December 31, 2019 and 2018, the Company repurchased 4,011 and 3,774 shares, respectively, of common stock, now held as treasury stock, for aggregate purchase prices of $649,000 and $477,000, respectively. Scientific Advisory Board Awards During the years ended December 31, 2019 and 2018, the Company granted a total of 1,960 and 2,456 shares, respectively, of fully vested common stock to non-employee members of the Scientific Advisory Board for services performed in 2018 and 2017, respectively. The fair value of the shares issued to members of the Scientific Advisory Board was $300,000 for both years ended December 31, 2019 and 2018. Dividends During the year ended December 31, 2019, the Company declared and paid cash dividends of $0.40 per common share, or $18.9 million, on the Company’s outstanding common stock. On February 18, 2020, the Company’s Board of Directors declared a first quarter dividend of $0.15 per common share to be paid on March 31, 2020 to all shareholders of record as of the close of business on March 17, 2020. All future dividends will be subject to the approval of the Company’s Board of Directors.

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE LOSS	12 Months Ended
	Dec. 31, 2019
Accumulated Other Comprehensive Income Loss Net Of Tax [Abstract]
ACCUMULATED OTHER COMPREHENSIVE LOSS	13. ACCUMULATED OTHER COMPREHENSIVE LOSS: Amounts related to the changes in accumulated other comprehensive loss were as follows (in thousands): Unrealized Gain (Loss) on Available-for- Sale-Securities Net Unrealized Gain (Loss) on Retirement Plan (2) Change in Cumulative Foreign Currency Translation Adjustment Total Affected Line items in the Consolidated Statements of Income Balance January 1, 2017, net of tax $ (246 ) $ (10,355 ) $ (65 ) $ (10,666 ) Other comprehensive loss before reclassification (12 ) (2,184 ) 28 (2,168 ) Reclassification to net income (1) — 1,370 — 1,370 Selling, general and administrative, research and development and cost of sales Change during period (12 ) (814 ) 28 (798 ) Balance December 31, 2017, net of tax (258 ) (11,169 ) (37 ) (11,464 ) Other comprehensive gain (loss) before reclassification 268 (6,690 ) (9 ) (6,431 ) Reclassification to net income (1) — 1,661 — 1,661 Selling, general and administrative, research and development and cost of sales Change during period 268 (5,029 ) (9 ) (4,770 ) Balance December 31, 2018, net of tax 10 (16,198 ) (46 ) (16,234 ) Other comprehensive gain (loss) before reclassification 181 (3,492 ) — (3,311 ) Reclassification to net income (1) — 2,523 25 2,548 Selling, general and administrative, research and development and cost of sales Change during period 181 (969 ) 25 (763 ) Balance December 31, 2019, net of tax $ 191 $ (17,167 ) $ (21 ) $ (16,997 ) (1) The Company reclassified amortization of prior service cost, actuarial loss and plan amendment cost for its retirement plan from accumulated other comprehensive loss to net income of $2.5 million, $1.7 million and $1.4 million for the years ended December 31, 2019, 2018 and 2017, respectively. (2) Refer to Note 15: Employee Retirement Plans

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION	12 Months Ended
	Dec. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
STOCK-BASED COMPENSATION	14. STOCK-BASED COMPENSATION: Equity Compensation Plan The Equity Compensation Plan provides for the granting of incentive and nonqualified stock options, shares of common stock, stock appreciation rights and performance units to employees, directors and consultants of the Company. Stock options are exercisable over periods determined by the Compensation Committee, but for no longer than 10 years from the grant date. Through December 31, 2019, the Company’s shareholders have approved increases in the number of shares reserved for issuance under the Equity Compensation Plan to 10,500,000, and have extended the term of the plan through 2024. As of December 31, 2019, there were 2,248,573 shares that remained available to be granted under the Equity Compensation Plan. Stock Options The following table summarizes the stock option activity during the year ended December 31, 2019 for all the grants under the Equity Compensation Plan (in thousands, except share and per share data): Options Weighted Average Exercise Price Outstanding at January 1, 2019 500 $ 10.04 Forfeited/Expired (500 ) 10.04 Outstanding at December 31, 2019 — $ — No stock options were granted during the years ended December 31, 2019, 2018 and 2017. The total intrinsic value of stock options exercised during the year ended December 31, 2017 was $146,000. No stock options were exercised during the years ended December 31, 2019 and 2018. There was no compensation expense recognized for the years ended December 31, 2019, 2018 and 2017. During the years ended December 31, 2019, 2018 and 2017, no shares of common stock were tendered to net share settle the exercise of options. Restricted Stock Award and Units The Company has issued restricted stock awards and units to employees and non-employees with vesting terms of one to six years. The fair value is equal to the market price of the Company’s common stock on the date of grant for awards granted to employees and equal to the market price at the end of the reporting period for unvested non-employee awards or upon the date of vesting for vested non-employee awards. Expense for restricted stock awards and units is amortized ratably over the vesting period for the awards issued to employees and using a graded vesting method for the awards issued to non-employees. The following table summarizes the activity related to restricted stock unit (RSU) share based payment awards: Number of Shares Weighted- Average Grant-Date Fair Value Unvested, January 1, 2019 92,381 $ 97.56 Granted 58,549 168.95 Vested (49,635 ) 87.96 Forfeited (2,485 ) 103.79 Unvested, December 31, 2019 98,810 $ 144.53 The weighted average grant-date fair value of RSU awards granted was $168.95, $115.48 and $116.58 during the years ended December 31, 2019, 2018 and 2017, respectively. The fair value as of the respective vesting dates of RSUs was $7.7 million, $8.1 million and $8.3 million for 2019, 2018 and 2017, respectively. The following table summarizes the activity related to restricted stock award (RSA) share based payment awards: Number of Shares Weighted- Average Grant-Date Fair Value Unvested, January 1, 2019 409,949 $ 46.74 Granted 73,640 194.19 Vested (171,946 ) 47.89 Unvested, December 31, 2019 311,643 $ 80.94 The weighted average grant-date fair value of RSA awards granted was $194.19, $122.15 and $83.25 during the years ended December 31, 2019, 2018 and 2017, respectively. The fair value as of the respective vesting dates of RSAs was $28.4 million, $17.7 million and $14.8 million for 2019, 2018 and 2017, respectively. For the years ended December 31, 2019, 2018 and 2017, the Company recorded, as compensation charges related to restricted stock awards and units issued to employees and non-employees, selling, general and administrative expense of $10.0 million, $7.6 million and $8.5 million, respectively, cost of sales of $1.1 million, $758,000 and $443,000, respectively, and research and development expense of $2.5 million, $2.0 million and $1.6 million, respectively. In connection with the vesting of restricted stock awards and units during the years ended December 31, 2019, 2018 and 2017, 86,075, 86,679 and 89,661 shares, respectively, with aggregate fair values of $14.0 million, $9.2 million and $7.8 million, respectively, were withheld in satisfaction of tax withholding obligations and are reflected as a financing activity within the Consolidated Statements of Cash Flows. For the years ended December 31, 2019, 2018 and 2017, the Company recorded as compensation charges related to all restricted stock units to non-employee members of the Scientific Advisory Board, whose unvested shares are marked to market each reporting period, research and development expense of $632,000, $64,000 and $976,000, respectively. The Company has granted restricted stock units to non-employee members of the Board of Directors with quarterly vesting over a period of approximately one year. The fair value is equal to the market price of the Company’s common stock on the date of grant. The restricted stock units are issued and expense is recognized ratably over the vesting period. For the years ended December 31, 2019, 2018 and 2017, the Company recorded compensation charges for services performed, related to all restricted stock units granted to non-employee members of the Board of Directors, selling, general and administrative expense of $916,000, $4.3 million and $1.6 million, respectively. In connection with the vesting of the restricted stock, the Company issued to non-employee members of the Board of Directors 9,332, 25,000 and 27,500 shares during the years ended December 31, 2019, 2018 and 2017, respectively. As of December 31, 2019, the total unrecognized expense related to all restricted stock awards and units was $30.0 million, which the Company expects to recognize over a weighted average period of 2.25 years. Performance Unit Awards Each performance unit award is subject to both a performance-vesting requirement (either performance-based or market-based) and a service-vesting requirement. The performance-based vesting requirement is tied to the Company's cumulative revenue growth compared to the cumulative revenue growth of companies comprising the Nasdaq Electronics Components Index, as measured over a specific performance period. The market-based vesting requirement is tied to the Company's total shareholder return relative to the total shareholder return of companies comprising the Nasdaq Electronics Components Index, as measured over a specific performance period. The maximum number of performance units that may vest based on performance is two times the shares granted. Further, if the Company's total shareholder return is negative, the performance units may not vest at all. The following table summarizes the activity related to performance unit awards (PSU) share based payment awards: Number of Shares Weighted- Average Grant-Date Fair Value Unvested, January 1, 2019 52,730 $ 86.43 Granted 25,746 198.72 Vested (40,695 ) 59.09 Unvested, December 31, 2019 37,781 $ 134.97 During the years ended December 31, 2019, 2018 and 2017, the Company granted 10,096, 40,601 and 24,664 performance units, respectively, of which 5,050, 6,022 and 7,817 units, respectively, are subject to performance-based vesting requirements and 5,046, 6,025 and 7,821 units, respectively, are subject to market-based vesting requirements, and will vest over the terms described below. During the years ended December 31, 2019, 2018 and 2017, there were also 15,650, 28,554 and 9,026 incremental performance-based shares, respectively, that vested resulting from an increased vesting factor based on Company performance. The weighted average grant date fair value of the performance unit awards granted was $198.72, $119.62 and $105.65 during the years ended December 31, 2019, 2018 and 2017, respectively, as determined by the Company’s common stock on date of grant for the units with performance-based vesting and a Monte-Carlo simulation for the units with market-based vesting. For the years ended December 31, 2019, 2018 and 2017, the Company recorded, as compensation charges related to all performance stock units, selling, general and administrative expense of $1.7 million, $1.3 million and $1.2 million, respectively, cost of sales of $208,000, $141,000 and $119,000, respectively, and research and development expense of $419,000, $330,000 and $276,000, respectively. In connection with the vesting of performance units during the years ended December 31, 2019, 2018 and 2017, 16,668, 25,208 and 19,217 shares, respectively, with aggregate fair values of $2.6 million, $2.9 million and $1.6 million, respectively, were withheld in satisfaction of tax withholding obligations and are reflected as a financing activity within the Consolidated Statements of Cash Flows. As of December 31, 2019, the total unrecognized compensation expense related to performance unit awards was $2.7 million, which the Company expects to recognize over a weighted average period of 1.87 years. Employee Stock Purchase Plan On April 7, 2009, the Board of Directors of the Company adopted an Employee Stock Purchase Plan (ESPP). The ESPP was approved by the Company’s shareholders and became effective on June 25, 2009. The Company has reserved 1,000,000 shares of common stock for issuance under the ESPP. Unless terminated sooner by the Board of Directors, the ESPP will expire when all reserved shares have been issued. Eligible employees may elect to contribute to the ESPP through payroll deductions during consecutive three-month purchase periods, the first of which began on July 1, 2009. Each employee who elects to participate will be deemed to have been granted an option to purchase shares of the Company’s common stock on the first day of the purchase period. Unless the employee opts out during the purchase period, the option will automatically be exercised on the last day of the period, which is the purchase date, based on the employee’s accumulated contributions to the ESPP. The purchase price will equal 85% of the lesser of the closing price per share of common stock on the first day of the period or the last business day of the period. Employees may allocate up to 10% of their base compensation to purchase shares of common stock under the ESPP; however, each employee may purchase no more than 12,500 shares on a given purchase date, and no employee may purchase more than $25,000 of common stock under the ESPP during a given calendar year. For the years ended December 31, 2019, 2018 and 2017, the Company issued 7,492, 10,303 and 9,730 shares, respectively, of its common stock under the ESPP, resulting in proceeds of $889,000, $798,000 and $734,000, respectively. For the years ended December 31, 2019, 2018 and 2017, the Company recorded charges of $79,000, $82,000 and $69,000, respectively, to selling, general and administrative expense, $73,000, $81,000, $46,000, respectively, to cost of sales and $118,000, $130,000 and $94,000, respectively, to research and development expense, related to the ESPP equal to the amount of the discount and the value of the look-back feature.

EMPLOYEE RETIREMENT PLANS

EMPLOYEE RETIREMENT PLANS	12 Months Ended
	Dec. 31, 2019
Defined Benefit Pension Plans And Defined Benefit Postretirement Plans Disclosure [Abstract]
EMPLOYEE RETIREMENT PLANS	15. EMPLOYEE RETIREMENT PLANS: Defined Contribution Plan The Company maintains the Universal Display Corporation 401(k) Plan (the Plan) in accordance with the provisions of Section 401(k) of the Internal Revenue Code (the Code). The Plan covers substantially all full-time employees of the Company. Participants may contribute up to 90% of their total compensation to the Plan, not to exceed the limit as defined in the Code. Once an employee is eligible to participate in the Plan, the Company will make a non-elective contribution equal to 3% of the employee’s total compensation. For the years ended December 31, 2019, 2018 and 2017, the Company contributed $880,000, $1.2 million and $601,000, respectively, to the Plan. Defined Benefit Plan On March 18, 2010, the Compensation Committee and the Board of Directors of the Company approved and adopted the Universal Display Corporation Supplemental Executive Retirement Plan (SERP), effective as of April 1, 2010. On March 3, 2015, the Compensation Committee and the Board of Directors amended the SERP to include salary and bonus as part of the plan. Prior to this amendment, the SERP benefit did not take into account any bonuses. The purpose of the SERP, which is unfunded, is to provide certain of the Company’s key employees with supplemental pension benefits following a cessation of their employment. As of December 31, 2019 seven The SERP benefit is based on a percentage of the participant’s annual base salary and in certain cases, the participant's average annual bonus for the most recent three fiscal years ending prior to the participant's date of termination of employment with the Company for the life of the participant. For this purpose, annual base salary means 12 times the average monthly base salary paid or payable to the participant during the 24-month period immediately preceding the participant’s date of termination of employment, or, if required, the date of a change in control of the Company. Under the SERP, if a participant resigns or is terminated without cause at or after age 65 and with at least 20 years of service, he or she will be eligible to receive a SERP benefit. The benefit is based on a percentage of the participant’s annual base salary and bonus for the life of the participant. This percentage is 50%, 25% or 15%, depending on the participant’s benefit class. If a participant resigns at or after age 65 and with at least 15 years of service, he or she will be eligible to receive a prorated SERP benefit. If a participant is terminated without cause or on account of a disability after at least 15 years of service, he or she will be eligible to receive a prorated SERP benefit regardless of age. The prorated benefit in either case would be based on the participant’s number of years of service (up to 20), divided by 20 . In the event a participant is terminated for cause, his or her SERP benefit and any future benefit payments are subject to immediate forfeiture . The SERP benefit is payable in installments over 10 years, beginning at the later of age 65 or the date of the participant’s separation from service. Payments are based on a present value calculation of the benefit amount for the actuarial remaining life expectancy of the participant. This calculation is made as of the date benefit payments are to begin (later of age 65 or separation from service). If the participant dies after reaching age 65, any future or remaining benefit payments are made to the participant’s beneficiary or estate. If the participant dies before reaching age 65, the benefit is forfeited. In the event of a change in control of the Company, each participant will become immediately vested in his or her SERP benefit. Unless the participant’s benefit has already fully vested, if the participant has less than 20 years of service at the time of the change in control, he or she will receive a prorated benefit based on his or her number of years of service (up to 20), divided by 20. If the change in control qualifies as a “change in control event” for purposes of Section 409A of the Internal Revenue Code, then each participant (including former employees who are entitled to SERP benefits) will receive a lump sum cash payment equal to the present value of the benefit immediately upon the change in control. Certain of the Company’s executive officers are designated as special participants under the SERP. If these participants resign or are terminated without cause after 20 years of service, or at or after age 65 and with at least 15 years of service, they will be eligible to receive a SERP benefit. If they are terminated without cause or on account of a disability, they will be eligible to receive a prorated SERP benefit regardless of age. The prorated benefit would be based on the participant’s number of years of service (up to 20), divided by 20. The SERP benefit for special participants is based on 50% of their annual base salary and bonus for their life and the life of their surviving spouse, if any. Payments are based on a present value calculation of the benefit amount for the actuarial remaining life expectancies of the participant and their surviving spouse, if any. If they die before reaching age 65, the benefit is not forfeited if the surviving spouse, if any, lives until the participant would have reached age 65. If their spouse also dies before the participant would have reached age 65, the benefit is forfeited. The Company records amounts relating to the SERP based on calculations that incorporate various actuarial and other assumptions, including discount rates, rate of compensation increases, retirement dates, and life expectancies. The net periodic costs are recognized as employees render the services necessary to earn the SERP benefits. In connection with the initiation and subsequent amendments of the SERP, the Company recorded cost related to prior service of $21.7 million as accumulated other comprehensive loss as of December 31, 2019. The prior service cost is being amortized as a component of net periodic pension cost over the average of the remaining service period of the employees expected to receive benefits under the plan. The prior service cost expected to be amortized for the year ending December 31, 2020 is $3.4 million. Information relating to the Company’s plan is as follows (in thousands): Year Ended December 31, 2019 2018 Change in benefit obligation: Benefit obligation, beginning of year $ 44,055 $ 33,176 Service cost 969 1,301 Interest cost 1,613 1,047 Actuarial loss 4,480 8,531 Benefit obligation, end of year 51,117 44,055 Fair value of plan assets — — Unfunded status of the plan, end of year $ 51,117 $ 44,055 Current liability — — Noncurrent liability $ 51,117 $ 44,055 The accumulated benefit obligation for the plan was $48.1 million and $41.3 million 2019 2018 The components of net periodic pension cost were as follows (in thousands): Year Ended December 31, 2019 2018 2017 Service cost $ 969 $ 1,301 $ 1,214 Interest cost 1,613 1,047 1,013 Amortization of prior service cost 1,595 1,683 1,667 Amortization of loss 1,641 435 457 Total net periodic benefit cost $ 5,818 $ 4,466 $ 4,351 The measurement date is the Company’s fiscal year end. The net periodic pension cost is based on assumptions determined at the prior year end measurement date. Assumptions used to determine the year end benefit obligation were as follows: Year Ended December 31, 2019 2018 Discount rate 2.64 % 3.82 % Rate of compensation increases 3.50 % 3.50 % Assumptions used to determine the net periodic pension cost were as follows: Year Ended December 31, 2019 2018 2017 Discount rate 3.82 % 3.22 % 3.41 % Rate of compensation increases 3.50 % 3.50 % 3.50 % Actuarial gains and losses are amortized from accumulated other comprehensive loss into net periodic pension cost over future years based upon the average remaining service period of active plan participants, when the accumulation of such gains or losses exceeds 10% of the year end benefit obligation. The cost or benefit of plan changes that increase or decrease benefits for prior employee service (prior service cost or credit) is included in the Company’s results of income on a straight-line basis over the average remaining service period of active plan participants. The estimated amounts to be amortized from accumulated other comprehensive loss into the net periodic pension cost in 2020 are as follows (in thousands): Amortization of prior service cost $ 1,099 Amortization of loss 2,260 Total $ 3,359 Benefit payments, which reflect estimated future service, are currently expected to be paid as follows (in thousands): Year Projected Benefits 2020 $ — 2021 3,777 2022 4,288 2023 4,618 2024 4,618 2025-2029 28,400 Thereafter 25,800

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	16. COMMITMENTS AND CONTINGENCIES: Commitments Under the 2006 Research Agreement with USC, the Company is obligated to make certain payments to USC based on work performed by USC under that agreement, and by Michigan under its subcontractor agreement with USC. See Note 10 for further explanation. Under the terms of the 1997 Amended License Agreement, the Company is required to make minimum royalty payments to Princeton. See Note 10 for further explanation. The Company has agreements with six executive officers and two employees which provide for certain cash and other benefits upon termination of employment of the officer or employee in connection with a change in control of the Company. If the executive’s employment is terminated in connection with the change in control, the executive is entitled to a lump-sum cash payment equal to two times the sum of the average annual base salary and bonus of the officer and immediate vesting of all stock options and other equity awards that may be outstanding at the date of the change in control, among other items. In order to manage manufacturing lead times and help ensure adequate material supply, the Company entered into a New OLED Materials Agreement (see Note 11) that allows PPG to procure and produce inventory based upon criteria as defined by the Company. These purchase commitments consist of firm, noncancelable and unconditional commitments. In certain instances, this agreement allows the Company the option to reschedule and adjust the Company’s requirements based on its business needs prior to firm orders being placed. As of December 31, 2019, 2018 and 2017, the Company had purchase commitments for inventory of $22.0 million, $15.9 million and $14.2 million, respectively. Patent Related Challenges and Oppositions Each major jurisdiction in the world that issues patents provides both third parties and applicants an opportunity to seek a further review of an issued patent. The process for requesting and considering such reviews is specific to the jurisdiction that issued the patent in question, and generally does not provide for claims of monetary damages or a review of specific claims of infringement. The conclusions made by the reviewing administrative bodies tend to be appealable and generally are limited in scope and applicability to the specific claims and jurisdiction in question. The Company believes that opposition proceedings are frequently commenced in the ordinary course of business by third parties who may believe that one or more claims in a patent do not comply with the technical or legal requirements of the specific jurisdiction in which the patent was issued. The Company views these proceedings as reflective of its goal of obtaining the broadest legally permissible patent coverage permitted in each jurisdiction. Once a proceeding is initiated, as a general matter, the issued patent continues to be presumed valid until the jurisdiction’s applicable administrative body issues a final non-appealable decision. Depending on the jurisdiction, the outcome of these proceedings could include affirmation, denial or modification of some or all of the originally issued claims. The Company believes that as OLED technology becomes more established and its patent portfolio increases in size, so will the number of these proceedings. Below is a summary of an active proceeding that has been commenced against an issued patent that is exclusively licensed to the Company. The Company does not believe that the confirmation, loss or modification of the Company’s rights in any individual claim or set of claims that are the subject of the following legal proceeding would have a material impact on the Company’s materials sales or licensing business or on the Company’s Consolidated Financial Statements, including its Consolidated Statements of Income, as a whole. However, as noted within the description, the following proceeding involves an issued patent that relates to the Company’s fundamental phosphorescent OLED technologies and the Company intends to vigorously defend against claims that, in the Company’s opinion, seek to restrict or reduce the scope of the originally issued claim, which may require the expenditure of significant amounts of the Company’s resources. In certain circumstances, when permitted, the Company may also utilize a proceeding to request modification of the claims to better distinguish the patented invention from any newly identified prior art and/or improve the claim scope of the patent relative to commercially important categories of the invention. Opposition to European Patent No. 1390962 On November 16, 2011, Osram AG and BASF SE each filed a Notice of Opposition to European Patent No. 1390962 (the EP '962 patent), which relates to the Company’s white phosphorescent OLED technology. The EP '962 patent, which was issued on February 16, 2011, is a European counterpart patent to U.S. patents 7,009,338 and 7,285,907. They are exclusively licensed to the Company by Princeton, and the Company is required to pay all legal costs and fees associated with this proceeding. The European Patent Office (EPO) combined the oppositions into a single opposition proceeding, and a hearing on this matter was held in December 2015, wherein the EPO Opposition Division revoked the patent claims for alleged insufficiencies under European Patent Convention Article 83. The Company believes the EPO's decision relating to the original claims is erroneous, and has appealed the decision. Subsequent to the filing of the appeal, BASF withdrew its opposition to the patent. The EPO Opposition Division has scheduled and appeal hearing for the third quarter of 2020. The patent, as originally granted, is deemed valid during the pendency of the appeals process. At this time, based on its current knowledge, the Company believes that the patent being challenged should be declared valid and that all or a significant portion of the Company's claims should be upheld. However, the Company cannot make any assurances of this result. In addition to the above proceeding and now concluded proceedings which have been referenced in prior filings, from time to time, the Company may have other proceedings that are pending which relate to patents the Company acquired as part of the Fujifilm patent or BASF OLED patent acquisitions or which relate to technologies that are not currently widely used in the marketplace.

CONCENTRATION OF RISK

CONCENTRATION OF RISK	12 Months Ended
	Dec. 31, 2019
Risks And Uncertainties [Abstract]
CONCENTRATION OF RISK	17. CONCENTRATION OF RISK: Revenues and accounts receivable from the Company's largest customers for the years ended December 31, were as follows (in thousands): 2019 2018 2017 Customer % of Total Revenue Accounts Receivable % of Total Revenue Accounts Receivable % of Total Revenue Accounts Receivable A 44% $ 13,830 37% $ 14,419 62% $ 19,588 B 27% 19,346 33% 11,990 24% 17,348 C 15% 10,592 10% 9,071 6% 10,632 Revenues from outside of North America represented approximately 97%, 94 December 31, 2018 2017 Year Ended December 31, Country 2019 2018 2017 South Korea $ 250,562 $ 171,915 $ 289,418 China 135,259 51,931 24,892 Japan 5,276 6,823 8,542 Other non-U.S. locations 2,270 2,967 2,438 Total non-U.S. locations 393,367 233,636 325,290 United States 11,810 13,778 10,339 Total revenue $ 405,177 $ 247,414 $ 335,629 The Company attributes revenue to different geographic areas on the basis of the location of the customer. Long-lived assets (net), by geographic area are as follows (in thousands): 2019 2018 United States $ 80,027 $ 64,560 Other 7,845 5,179 Total long-lived assets $ 87,872 $ 69,739 Substantially all chemical materials were purchased from one supplier. See Note 11.

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
INCOME TAXES	18. INCOME TAXES: The components of income before income taxes are as follows (in thousands): Year ended December 31, 2019 2018 2017 United States $ 53,629 $ 13,565 $ 100,260 Foreign 116,276 50,746 49,277 Income before income taxes $ 169,905 $ 64,311 $ 149,537 The components of the income tax expense are as follows (in thousands): Year ended December 31, 2019 2018 2017 Current income tax expense: Federal $ (20,108 ) $ (9,097 ) $ (5,817 ) State (755 ) (511 ) (54 ) Foreign (16,514 ) (8,677 ) (15,406 ) (37,377 ) (18,285 ) (21,277 ) Deferred income tax benefit (expense): Federal 5,208 12,622 (24,425 ) State 1,054 611 (23 ) Foreign (486 ) (419 ) 73 5,776 12,814 (24,375 ) Income tax expense $ (31,601 ) $ (5,471 ) $ (45,652 ) Reconciliation of the statutory U.S. federal tax rate to the Company's effective tax rate is as follows: Year ended December 31, 2019 2018 2017 Statutory U.S. federal income tax rate 21.0 % 21.0 % 35.0 % State income taxes, net of federal benefit 0.1 (0.2 ) — Effect of foreign operations (5.4 ) (4.7 ) (7.1 ) Accruals and reserves (1.1 ) — 0.1 Nondeductible employee compensation 2.5 1.7 1.5 Research tax credits (1.4 ) (2.7 ) (0.7 ) Change in valuation allowance — — (4.1 ) Stock based compensation (1.7 ) (2.7 ) (1.9 ) U.S. Tax Cuts and Jobs Act — (3.5 ) 7.7 U.S. International Tax (Sub F, GILTI, FDII) 3.8 (1.2 ) — Other 0.8 0.8 — Effective tax rate 18.6 % 8.5 % 30.5 % The following table summarizes Company tax loss and tax credit carry forwards for tax return purposes at December 31, 2019 (in thousands): Related Tax Deduction Tax Benefit Expiration Date Tax credit carry forwards: State research tax credits n/a $ 3,368 2026 to 2034 Total credit carry forwards n/a $ 3,368 Significant components of the Company's net deferred tax assets and liabilities are as follows (in thousands): December 31, 2019 2018 Deferred tax asset: Capitalized technology license $ 560 $ 553 Capitalized research expenditures 3,319 4,710 Accruals and reserves 4,130 2,890 Retirement plan 11,363 9,570 Deferred revenue 14,354 12,028 Tax credit carry forwards 3,997 2,895 Stock-based compensation 1,884 1,701 Other 1,682 47 41,289 34,394 Valuation allowance (3,368 ) (2,893 ) Deferred tax assets 37,921 31,501 Deferred tax liability: Accruals and reserves (7,546 ) (7,124 ) Deferred tax liabilities (7,546 ) (7,124 ) Net deferred tax assets $ 30,375 $ 24,377 In assessing the realizability of deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent on the Company's ability to generate future taxable income to obtain benefit from the reversal of temporary differences, net operating loss carryforwards and tax credits. As part of its assessment, management considers the scheduled reversal of deferred tax liabilities, projected future taxable income, and tax planning strategies. At this time there is no evidence to release the valuation allowance that relates to the New Jersey research and development credit. On December 27, 2018, the Korean Supreme Court, citing prior cases, held that the applicable law and interpretation of the Korea-U.S. Tax Treaty were clear that only royalties paid with respect to Korean registered patents are Korean source income and subject to Korean withholding tax. Based on this decision, the Company has decided to litigate the Korean withholding taxes paid or withheld on the 2018 and 2019 royalty payments and has engaged a leading Korean law firm which has advised that there is a more-likely-than-not chance of success. As a result, as of December 31, 2019 and 2018, the Company has recorded a long-term asset of $26.9 million and $13.6 million, respectively, representing the allocation of withholding to non-Korean patents and a long-term liability of $25.7 million and $7.7 million, respectively, for estimated amounts due to the U.S. Federal government based on the amendment of U.S. tax returns for lower withholding amounts. With respect to the Korean withholding for the years 2011 through 2017, the Company has decided to continue the U.S.-Korean Mutual Agreement Procedure which was accepted by the Korean National Tax Service (KNTS) on September 15, 2017. The Company believes that it is more-likely-than-not that a favorable settlement will be reached resulting in a reduction of the Korean withholding taxes previously withheld since 2011. A long-term asset of $36.9 million for estimated refunds due from the Korean government, a long-term payable of $16.2 million for estimated amounts due to the U.S. Federal government based on amendment of prior year U.S. tax returns for the lower withholding amounts, and a reduction of deferred tax assets for foreign tax credits and R&D credits of $20.7 million has been recorded on the December 31, 2019 and 2018 Consolidated Balance Sheets for this matter. On October 30, 2018, the KNTS concluded a tax audit with LG Display that included the licensing and royalty payments made to UDC Ireland during the years 2015 through 2017. The KNTS questioned whether UDC Ireland was the beneficial owner of these payments and assessed UDC Ireland a charge of $13.2 million for withholding and interest for the three-year For the years ended December 31, 2019, 2018 and 2017, the Company has incurred Korean withholding tax of $14.9 million, $14.9 million and $17.6 million, respectively; which is currently being appealed based on the interpretation of the Korea-U.S. Tax Treaty and recent Korean Supreme Court decisions. The Company’s 2013 federal income tax return was audited by the Internal Revenue Services with no change; the years 201 6 to 201 9 are open and subject to examination. The State of New Jersey is currently auditing the 2014 to 2017 tax returns of UDC Inc. The state and foreign tax returns are open for a period of generally three to four years . The above estimates may change in the future and ultimately upon settlement of these uncertain tax positions.

REVENUE RECOGNITION

REVENUE RECOGNITION	12 Months Ended
	Dec. 31, 2019
Revenue From Contract With Customer [Abstract]
REVENUE RECOGNITION	19. REVENUE RECOGNITION: Effective on January 1, 2018, the Company recognizes revenue in accordance with ASC Topic 606, Revenue from Contracts with Customers (Topic 606) During the year ended December 31, 2019, the Company entered into a transaction with one of its customers for emitters involving elements of variable consideration. Due to the escalation in trade policy tension between the governments of China and the United States, the customer required a larger than normal shipment of emitters having a right to return them through March 15, 2020 in order to accommodate their uncertain production needs. Per Topic 606, the Company was constrained to recognizing revenue on this unique shipment to the extent that it was probable that a significant revenue reversal would not occur and deferred recognition of the remainder until after the inherent uncertainties of the transaction were resolved. These uncertainties include factors that are outside of the Company’s influence, including the customer’s production needs and complexities associated with the current international health and trade issues in China. For the years ended December 31, 2019, 2018 and 2017, the Company recorded 97%, 95% and 97%, respectively, of its revenue from sales of material and 3%, 5% and 3%, respectively, from the providing of services through Adesis. Contract Balances The following table provides information about assets and liabilities associated with our contracts from customers (in thousands): As of December 31, 2019 Accounts receivable $ 60,452 Short-term unbilled receivables 1,362 Long-term unbilled receivables — Short-term deferred revenue 97,333 Long-term deferred revenue 47,529 Short-term and long-term unbilled receivables are classified as other current assets and other assets, respectively, on the Consolidated Balance Sheets. The deferred revenue balance at December 31, 2019 will be recognized as materials are shipped to customers over the remaining contract periods. The significant customer contracts (individually representing greater than 10% of revenue) expire in 2022. As of December 31, 2019, the Company had $6.5 million of backlog associated with committed purchase orders from its customers for phosphorescent emitter material. These orders are anticipated to be fulfilled within the next 90 days. Significant changes in the unbilled receivables and deferred liabilities balances for the years ended December 31, 2019 and 2018, are as follows (in thousands): Year Ended December 31, 2019 Unbilled Receivables Increase (Decrease) Deferred Revenue (Increase) Decrease Balance at December 31, 2018 $ 1,020 $ (122,567 ) Revenue recognized that was previously included in deferred revenue — 133,394 Increases due to cash received — (157,321 ) Cumulative catch-up adjustment arising from changes in estimates of transaction price — 1,632 Unbilled receivables recognized 1,834 — Transferred to receivables from unbilled receivables (1,492 ) — Net change 342 (22,295 ) Balance at December 31, 2019 $ 1,362 $ (144,862 ) Year Ended December 31, 2018 Unbilled Receivables Increase (Decrease) Deferred Revenue (Increase) Decrease Balance at December 31, 2017 $ 70 $ (38,883 ) Adoption of Topic 606 on January 1, 2018 307 (21,307 ) Adjusted balance on January 1, 2018 377 (60,190 ) Revenue recognized that was previously included in deferred revenue — 64,562 Increases due to cash received — (130,639 ) Cumulative catch-up adjustment arising from changes in estimates of transaction price — 3,700 Unbilled receivables recognized 2,024 — Transferred to receivables from unbilled receivables (1,381 ) — Net change 643 (62,377 ) Balance at December 31, 2018 $ 1,020 $ (122,567 ) Adoption of Topic 606 The Company adopted Topic 606 beginning January 1, 2018 using the “modified retrospective” approach, meaning the standard was applied only to the most current period presented in the financial statements, with a cumulative adjustment to retained earnings. Under this transition method, the Company elected to apply Topic 606 only to contracts that were not complete at the initial adoption date. Adoption of the new standard resulted in a reduction of retained earnings of $17.1 million on January 1, 2018. The new standard impacts how the Company recognizes revenue on its commercial license and material supply agreements with customers. Previously, the Company recognized license fees on a straight-line basis or as received from the customer, and royalty revenue one quarter in arrears based on sales information received from its customers typically received after disclosing that quarter’s results. Under the new standard, total contract consideration is estimated and recognized over the contract term based on material units sold at its estimated per unit fee. Total contract consideration includes fixed amounts designated in contracts with customers as license fees as well as estimates of material fees and royalties to be earned. Prior to the adoption of Topic 606 on January 1, 2018, the Company recognized revenue in accordance with ASC Topic 605, Revenue Recognition (Topic 605) The following tables summarize the impacts of adopting Topic 606 on the Company’s Consolidated Financial Statements for the year ended December 31, 2018 (in thousands) Consolidated Balance Sheet Impact of Changes in Accounting Policies December 31, 2018 As Reported Adjustment Balances Without Adoption of Topic 606 ASSETS Other assets (current and non-current) $ 70,892 $ — $ 70,892 Deferred income taxes 24,377 (11,153 ) 13,224 TOTAL ASSETS 933,424 (11,153 ) 922,271 LIABILITIES AND SHAREHOLDERS' EQUITY Deferred revenue (current and non-current) 122,567 (99,885 ) 22,682 Retained earnings 129,552 88,732 218,284 TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY 933,424 (11,153 ) 922,271 Consolidated Statement of Income Impact of Changes in Accounting Policies Year Ended December 31, 2018 As Reported Adjustment Balances Without Adoption of Topic 606 REVENUE $ 247,414 $ 78,885 $ 326,299 Gross margin 193,873 78,885 272,758 OPERATING INCOME 56,735 78,885 135,620 INCOME BEFORE INCOME TAXES 64,311 78,885 143,196 INCOME TAX EXPENSE (5,471 ) (7,252 ) (12,723 ) NET INCOME 58,840 71,633 130,473 Consolidated Statement of Cash Flows Impact of Changes in Accounting Policies Year Ended December 31, 2018 As Reported Adjustment Balances Without Adoption of Topic 606 CASH FLOWS FROM OPERATING ACTIVITIES: Net income $ 58,840 $ 71,633 $ 130,473 Amortization of deferred revenue and recognition of unbilled receivables (68,905 ) (81,991 ) (150,896 ) Deferred income tax (benefit) expense (12,814 ) 10,358 (2,456 ) Other assets (current and non-current) (59,062 ) — (59,062 ) Net cash provided by operating activities 121,796 — 121,796

NET INCOME PER COMMON SHARE

NET INCOME PER COMMON SHARE	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
NET INCOME PER COMMON SHARE	20 . NET INCOME PER COMMON SHARE: The Company computes earnings per share in accordance with ASC Topic 260, Earnings per Share Basic net income per common share is computed by dividing net income allocated to common shareholders by the weighted-average number of shares of common stock outstanding for the period excluding unvested restricted stock units and performance units. Net income allocated to the holders of the Company's unvested restricted stock awards is calculated based on the shareholders proportionate share of weighted average shares of common stock outstanding on an if-converted basis. For purposes of determining diluted net income per common share, basic net income per share is further adjusted to include the effect of potential dilutive common shares outstanding, including stock options, restricted stock units and performance units, and the impact of shares to be issued under the E mployee Stock Purchase Plan . The following table is a reconciliation of net income and the shares used in calculating basic and diluted net income per common share for the year ended December 31, 2019, 2018 and 2017 (in thousands, except share and per share data): Year Ended December 31, 2019 2018 2015 Numerator: Net income $ 138,304 $ 58,840 $ 103,885 Adjustment for Basic EPS: Earnings allocated to unvested shareholders (1,106 ) (690 ) (1,638 ) Adjusted net income $ 137,198 $ 58,150 $ 102,247 Denominator: Weighted average common shares outstanding – Basic 46,959,775 46,849,588 46,725,289 Effect of dilutive shares: Common stock equivalents arising from stock options and ESPP 1,334 1,956 2,611 Restricted stock awards and units and performance units 34,353 45,222 77,294 Weighted average common shares outstanding – Diluted 46,995,462 46,896,766 46,805,194 Net income per common share: Basic $ 2.92 $ 1.24 $ 2.19 Diluted $ 2.92 $ 1.24 $ 2.18 For the year ended December 31, 2019, 2018, and 2017, the combined effects of unvested restricted stock awards, restricted stock units, performance unit awards and stock options of none, 4,414 and none, respectively, were excluded from the calculation of diluted EPS as their impact would have been antidilutive.

QUARTERLY SUPPLEMENTAL FINANCIA

QUARTERLY SUPPLEMENTAL FINANCIAL DATA (UNAUDITED)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
QUARTERLY SUPPLEMENTAL FINANCIAL DATA (UNAUDITED)	2 1 . QUARTERLY SUPPLEMENTAL FINANCIAL DATA (UNAUDITED): The following tables present certain unaudited consolidated quarterly financial information for each of the eight quarters in the two-year period ended December 31, 2019. In the opinion of Company management, this quarterly information has been prepared on the same basis as the Consolidated Financial Statements and includes all adjustments (consisting of only normal recurring adjustments) necessary to present fairly the information for the periods presented. The results of operations for any quarter are not necessarily indicative of the results for the full year or for any future period. Presented below is a summary of the unaudited quarterly financial information for the year ended December 31, 2019 (in thousands, except per share data): Three Months Ended March 31, 2019 June 30, 2019 September 30, 2019 December 31, 2019 Total Revenue $ 87,765 $ 118,168 $ 97,515 $ 101,729 $ 405,177 Net income $ 31,474 $ 43,440 $ 36,962 $ 26,428 $ 138,304 Net income per common share: Basic $ 0.66 $ 0.92 $ 0.78 $ 0.56 $ 2.92 Diluted $ 0.66 $ 0.92 $ 0.78 $ 0.56 $ 2.92 F-37 Presented below is a summary of the unaudited quarterly financial information for the year ended December 31, 201 8 (in thousands, except per share data): Three Months Ended March 31, 2018 June 30, 2018 September 30, 2018 December 31, 2018 Total Revenue $ 43,572 $ 56,149 $ 77,550 $ 70,143 $ 247,414 Net income $ 5,959 $ 10,814 $ 22,818 $ 19,249 $ 58,840 Net income per common share: Basic $ 0.13 $ 0.23 $ 0.48 $ 0.40 $ 1.24 Diluted $ 0.13 $ 0.23 $ 0.48 $ 0.40 $ 1.24 Per share amounts for each quarter have been calculated separately. Accordingly, quarterly amounts may not add to annual amounts.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The Consolidated Financial Statements include the accounts of Universal Display Corporation and its wholly owned subsidiaries, UDC, Inc., UDC Ireland Limited (UDC Ireland), Universal Display Corporation Hong Kong, Limited, Universal Display Corporation Korea, Y.H., Universal Display Corporation Japan GK, Universal Display Corporation China, Ltd., Adesis, Inc. (Adesis) and UDC Ventures LLC. UDC Ventures LLC was formed on March 1, 2019 as a corporate venture capital entity that will assist in funding companies that are developing innovative products and technologies that may be synergistic to those of the Company. All intercompany transactions and accounts have been eliminated.
Management's Use of Estimates	Management’s Use of Estimates The preparation of financial statements in conformity with U.S. generally accepted accounting principles (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. The estimates made are principally in the areas of revenue recognition including estimates of material unit sales and royalties, the useful life of acquired intangibles, lease liabilities, right-of-use assets, the use and recoverability of inventories, intangibles, investments and income taxes including realization of deferred tax assets, stock-based compensation and retirement benefit plan liabilities. Actual results could differ from those estimates.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid debt instruments purchased with an original maturity (maturity at the purchase date) of three months or less to be cash equivalents. The Company classifies its remaining investments as available-for-sale. These securities are carried at fair market value, with unrealized gains and losses reported in shareholders’ equity. Gains or losses on securities sold are based on the specific identification method.
Trade Accounts Receivable	Trade Accounts Receivable Trade accounts receivable are stated at the amount the Company expects to collect and do not bear interest. The Company considers the following factors when determining the collectability of specific customer accounts: customer credit-worthiness, past transaction history with the customer, current economic industry trends, and changes in customer payment terms. The Company’s accounts receivable balance is a result of chemical sales, royalties and license fees. These receivables have historically been paid timely. Due to the nature of the accounts receivable balance, the Company believes there is no significant risk of collection. If the financial condition of the Company’s customers were to deteriorate, adversely affecting their ability to make payments, allowances for doubtful accounts would be required. The allowance for doubtful accounts was $84,000, $77,000 and none at December 31, 2019, 2018 and 2017, respectively.
Inventories	Inventories Inventories consist of raw materials, work-in-process and finished goods, including inventory consigned to customers, and are stated at the lower of cost, determined on a first-in, first-out basis, or net realizable value. Inventory valuation and firm committed purchase order assessments are performed on a quarterly basis and those items that are identified to be obsolete or in excess of forecasted usage are written down to their estimated realizable value. Estimates of realizable value are based upon management’s analyses and assumptions, including, but not limited to, forecasted sales levels by product, expected product lifecycle, product development plans and future demand requirements. A 12-month rolling forecast based on factors, including, but not limited to, production cycles, anticipated product orders, marketing forecasts, backlog, and shipment activities is used in the inventory analysis. If market conditions are less favorable than forecasts or actual demand from customers is lower than estimates, additional inventory write-downs may be required. If demand is higher than expected, inventories that had previously been written down may be sold.
Property and Equipment	Property and Equipment Property and equipment are stated at cost and depreciated on a straight-line basis over the estimated useful life of 30 years for building, 15 years for building improvements, and three to seven years for office and lab equipment and furniture and fixtures. Repair and maintenance costs are charged to expense as incurred. Additions and betterments are capitalized. Major renewals and improvements are capitalized and minor replacements, maintenance, and repairs are charged to current operations as incurred. Upon retirement or disposal of assets, the cost and related accumulated depreciation are removed from the Consolidated Balance Sheets and any gain or loss is reflected in other operating expenses. Certain costs of computer software obtained for internal use are capitalized and amortized on a straight-line basis over three years. Costs for maintenance and training, as well as the cost of software that does not add functionality to an existing system, are expensed as incurred.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets Company management continually evaluates whether events or changes in circumstances might indicate that the remaining estimated useful life of long-lived assets may warrant revision, or that the remaining balance may not be recoverable. When factors indicate that long-lived assets should be evaluated for possible impairment, the Company uses an estimate of the related undiscounted cash flows in measuring whether the long-lived asset should be written down to fair value. Measurement of the amount of impairment would be based on generally accepted valuation methodologies, as deemed appropriate. As of December 31, 2019, Company management believed that no revision to the remaining useful lives or write-down of the Company’s long-lived assets was required, and similarly, no such revisions were required for the years ended December 31, 2018 or 2017.
Goodwill and Purchased Intangible Assets	Goodwill and Purchased Intangible Assets Goodwill is tested for impairment in the fourth fiscal quarter and, when specific circumstances dictate, between annual tests. Company management first assesses qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount as a basis for determining whether a quantitative goodwill impairment test is necessary. If it is concluded it is more likely than not that the fair value of a reporting unit exceeds its carrying amount, then a quantitative impairment assessment is not necessary. If it is determined that goodwill has been impaired, then its carrying value is written down to fair value. The goodwill impairment test involves a two-step process. The first step, identifying a potential impairment, compares the fair value of a reporting unit with its carrying amount, including goodwill. If the carrying value of the reporting unit exceeds its fair value, the second step would need to be conducted; otherwise, no further steps are necessary as no potential impairment exists. If necessary, the second step to measure the impairment loss would be to compare the implied fair value of the reporting unit goodwill with the carrying amount of that goodwill. Any excess of the reporting unit goodwill carrying value over the respective implied fair value is recognized as an impairment loss. The Company performed its annual impairment assessment as of December 31, 2019 utilizing a qualitative evaluation and concluded that it was more likely than not that the fair value of Adesis is great er than its carrying value. Company management believes it has made reasonable estimates and assumptions to calculate the fa ir value of the reporting unit. Future impairment tests will continue to be performed annually in the fiscal fourth quarter, or sooner if a triggering event occurs. As o f December 31, 201 9 , no indications of impairment exist ed . Purchased intangible assets with finite lives are carried at cost, less accumulated amortization. Amortization is computed over the estimated useful lives of the respective assets.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The carrying values of accounts receivable, other current assets, and accounts payable approximate fair value in the accompanying financial statements due to the short-term nature of those instruments. The Company’s other financial instruments, which include cash equivalents and investments, are carried at fair value.
Fair Value Measurements	Fair Value Measurements Fair value is defined as an exit price, representing the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants based on the highest and best use of the asset or liability. The Company uses valuation techniques to measure fair value that maximize the use of observable inputs and minimize the use of unobservable inputs. Observable inputs are inputs that market participants would use in pricing the asset or liability and are based on market data obtained from sources independent of the Company. Unobservable inputs reflect assumptions market participants would use in pricing the asset or liability based on the best information available in the circumstances
Minority Equity Investments	Minority Equity Investments The Company accounts for minority equity investments in companies that are not accounted for under the equity method as equity securities without readily determinable fair values. The fair values of these securities is based on original cost less impairments, if any, plus or minus changes resulting from observable price changes in orderly transactions for the identical or similar investment of the same issuer. Under this method, the share of income or loss of such companies is not included in the Consolidated Statements of Income. The carrying value of these investments is included in investments on the Consolidated Balance Sheets. The Company’s policy is to recognize an impairment in the value of its minority equity investments when clear evidence of an impairment exists. Factors considered in the assessment include a significant adverse change in the regulatory, economic, or technological environment, the completion of new equity financing that may indicate a decrease in value, the failure to complete new equity financing arrangements after seeking to raise additional funds, or the commencement of proceedings under which the assets of the business may be placed in receivership or liquidated to satisfy claims of debt and equity stakeholders.
Leases	Leases The Company is a lessee in operating leases primarily incurred to facilitate the expansion of manufacturing, research and development, and selling, general and administrative activities. As discussed in Note 8, effective January 1, 2019, the Company accounts for leases in accordance with Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) Topic 842, Leases Key estimates and judgements include how the Company determines the discount rate used to discount the unpaid lease payments to present value and the lease term. The Company monitors for events or changes in circumstances that could potentially require recognizing an impairment loss.
Revenue Recognition and Deferred Revenue	Revenue Recognition and Deferred Revenue Material sales relate to the Company’s sale of its OLED materials for incorporation into its customers’ commercial OLED products or for their OLED development and evaluation activities. Revenue associated with material sales is generally recognized at the time title passes, which is typically at the time of shipment or at the time of delivery, depending upon the contractual agreement between the parties. Revenue may be recognized after control of the material passes in the event the transaction price includes variable consideration. For example , a customer may be provided an extended opportunity to stock materials prior to use in mass production and given a general right of return not conditioned on breaches of warranties associated with the specific product. In such circumstances, revenue will be recognized at the earlier of the expiration of the customer’s general right of return or once it becomes unlikely that the customer will exercise its right of return . The rights and benefits to the Company’s OLED technologies are conveyed to the customer through technology license agreements and material supply agreements. The Company believes that the licenses and materials sold under these combined agreements are not distinct from each other for financial reporting purposes and as such, are accounted for as a single performance obligation. Accordingly, total contract consideration, including material, license and royalty fees, is estimated and recognized over the contract term based on material units sold at the estimated per unit fee over the life of the contract. Various estimates are relied upon to recognize revenue. The Company estimates total material units to be purchased by its customers over the contract term based on historical trends, industry estimates and its forecast process. Management uses the expected value method to estimate the material per unit fee. Additionally, management estimates the total sales-based royalties based on the estimated net sales revenue of its customers over the contract term. Contract research services revenue is revenue earned by Adesis by providing chemical materials synthesis research, development and commercialization for non-OLED applications on a contractual basis. These services range from intermediates for structure-activity relationship studies, reference agents and building blocks for combinatorial synthesis, re-synthesis of key intermediates, specialty organic chemistry needs, and selective toll manufacturing. These services are provided to third-party pharmaceutical and life sciences firms and other technology firms at fixed costs or on an annual contract basis. Revenue is recognized as services are performed with billing schedules and payment terms negotiated on a contract-by-contract basis. Payments received in excess of revenue recognized are recorded as deferred revenue. In other cases, services may be provided and revenue is recognized before the customer is invoiced. In these cases, revenue recognized will exceed amounts billed and the difference, representing amounts which are currently unbillable to the customer pursuant to contractual terms, is recorded as an unbilled receivable. Technology development and support revenue is revenue earned from development and technology evaluation agreements and commercialization assistance fees, along with, to a minimal extent, government contracts. Relating to the Company’s government contracts, the Company may receive reimbursements by government entities for all or a portion of the research and development costs the Company incurs. Revenues are recognized as services are performed, proportionally as research and development costs are incurred, or as defined milestones are achieved. In 2018, the Company entered into a commercial license agreement with Samsung Display Co., Ltd. (SDC). This agreement, which covers the manufacture and sale of specified OLED display materials, was effective as of January 1, 2018 and lasts through the end of 2022 with an additional two-year At the same time the Company entered into the current patent license agreement with SDC, the Company also entered into a new supplemental material purchase agreement with SDC. Under the supplemental material purchase agreement, SDC agrees to purchase from the Company a minimum amount of phosphorescent emitter materials for use in the manufacture of licensed products. This minimum commitment is subject to SDC’s requirements for phosphorescent emitter materials and the Company’s ability to meet these requirements over the term of the supplemental agreement. In 2015, the Company entered into an OLED patent license agreement and an OLED commercial supply agreement with LG Display Co., Ltd. (LG Display) which were effective as of January 1, 2015 and superseded the existing 2007 commercial supply agreement between the parties. The new agreements have a term that is set to expire by the end of 2022. The patent license agreement provides LG Display a non-exclusive, royalty bearing portfolio license to make and sell OLED displays under the Company's patent portfolio. The patent license calls for license fees, prepaid royalties and running royalties on licensed products. The agreements include customary provisions relating to warranties, indemnities, confidentiality, assignability and business terms. The agreements provide for certain other minimum obligations relating to the volume of material sales anticipated over the life of the agreements as well as minimum royalty revenue to be generated under the patent license agreement. The Company generates revenue under these agreements that are predominantly tied to LG Display’s sales of OLED licensed products. The OLED commercial supply agreement provides for the sale of materials for use by LG Display, which may include phosphorescent emitters and host materials. In 2016, the Company entered into long-term, multi-year OLED patent license and material purchase agreements with Tianma Micro-electronics Co., Ltd. (Tianma). Under the license agreement, the Company has granted Tianma non-exclusive license rights under various patents owned or controlled by the Company to manufacture and sell OLED display products. The license agreement calls for license fees and running royalties on licensed products. Additionally, the Company suppl ies phosphorescent OLED materials to Tianma for use in its licensed products. In 2017, the Company entered into long-term, multi-year agreements with BOE Technology Group Co., Ltd. (BOE). Under these agreements, the Company has granted BOE non-exclusive license rights under various patents owned or controlled by the Company to manufacture and sell OLED display products. The Company supplies phosphorescent OLED materials to BOE for use in its licensed products. In 2018, the Company entered into long-term, multi-year OLED patent license and material purchase agreements with Visionox Technology, Inc. (Visionox). Under the license agreement, the Company has granted Visionox non-exclusive license rights under various patents owned or controlled by the Company to manufacture and sell OLED display products. The license agreement calls for license fees and running royalties on licensed products. Additionally, the Company supplies phosphorescent OLED materials to Visionox for use in its licensed products. In 2019, the Company entered into an evaluation and commercial supply relationship with Wuhan China Star Optoelectronics Semiconductor Display Technology Co., Ltd. (CSOT). The Company has been collaborating with CSOT in the area of OLED display product design and manufacture and expects to continue to do so. All material sales transactions that are not variable consideration transactions are billed and due within 90 days and substantially all are transacted in U.S. dollars.
Cost of Sales	Cost of Sales Cost of sales consists of labor and material costs associated with the production of materials processed at the Company's manufacturing partners and at the Company's internal manufacturing processing facilities. The Company’s portion of cost of sales also includes depreciation of manufacturing equipment, as well as manufacturing overhead costs and inventory adjustments for excess and obsolete inventory.
Research and Development	Research and Development Expenditures for research and development are charged to operations as incurred.
Patent Costs	Patent Costs Costs associated with patent applications, patent prosecution, patent defense and the maintenance of patents are charged to expense as incurred. Costs to successfully defend a challenge to a patent are capitalized to the extent of an evident increase in the value of the patent. Costs that relate to an unsuccessful outcome are charged to expense.
Amortization of Acquired Technology	Amortization of Acquired Technology Amortization costs primarily relate to technology acquired from BASF and Fujifilm. These acquisitions were completed in the years ended December 31, 2016 and 2012, respectively. Acquisition costs are being amortized over a period of 10 years
Amortization of Other Intangible Assets	Amortization of Other Intangible Assets Other intangible assets from the Adesis acquisition are being amortized over a period of 10 to 15 years. See Note 7 for further discussion.
Translation of Foreign Currency Financial Statements and Foreign Currency Transactions	Translation of Foreign Currency Financial Statements and Foreign Currency Transactions The Company's reporting currency is the U.S. dollar. The functional currency for the Company's Ireland subsidiary is also the U.S. dollar and the functional currency for each of the Company's Asia-Pacific foreign subsidiaries is its local currency. The Company translates the amounts included in the Consolidated Statements of Income from its Asia-Pacific foreign subsidiaries into U.S. dollars at weighted-average exchange rates, which the Company believes are representative of the actual exchange rates on the dates of the transactions. The Company's foreign subsidiaries' assets and liabilities are translated into U.S. dollars from the local currency at the actual exchange rates as of the end of each reporting date, and the Company records the resulting foreign exchange translation adjustments in the Consolidated Balance Sheets as a component of accumulated other comprehensive loss. The overall effect of the translation of foreign currency and foreign currency transactions to date has been insignificant.
Income Taxes	Income Taxes Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. The Company recognizes the effect of income tax positions only if those positions are more likely than not of being sustained. Recognized income tax positions are measured at the largest amount of which the likelihood of realization is greater than 50%. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. The Company records interest and penalties, if any, related to unrecognized tax benefits as a component of tax expense.
Share-Based Payment Awards	Share-Based Payment Awards The Company recognizes in the Consolidated Statements of Income the grant-date fair value of equity based awards such as shares issued under employee stock purchase plans, restricted stock awards, restricted stock units and performance unit awards issued to employees and directors. The grant-date fair value of stock awards is based on the closing price of the stock on the date of grant. The fair value of share-based awards is recognized as compensation expense on a straight-line basis over the requisite service period, net of forfeitures. The Company issues new shares upon the respective grant, exercise or vesting of the share-based payment awards, as applicable. Performance unit awards are subject to either a performance-based or market-based vesting requirement. For performance-based vesting, the grant-date fair value of the award, based on fair value of the Company's common stock, is recognized over the service period, based on an assessment of the likelihood that the applicable performance goals will be achieved and compensation expense is periodically adjusted based on actual and expected performance. Compensation expense for performance unit awards with market-based vesting is calculated based on the estimated fair value as of the grant date utilizing a Monte Carlo simulation model and is recognized over the service period on a straight-line basis.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In February 2016, the FASB issued Accounting Standards Update (ASU) No. 2016-02, Leases (Topic 842) In January 2017, the FASB issued ASU No. 2017-04, Intangibles – Goodwill and Other (Topic 350): Simplifying the Test of Goodwill Impairment In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments: Credit Losses (Topic 326)

CASH, CASH EQUIVALENTS AND IN_2

CASH, CASH EQUIVALENTS AND INVESTMENTS (Tables)	12 Months Ended
	Dec. 31, 2019
Cash And Cash Equivalents [Abstract]
Schedule of Cash, Cash Equivalents	The following table provides details regarding the Company’s portfolio of cash and cash equivalents (in thousands): Amortized Unrealized Aggregate Cash and Cash Equivalents Classification Cost Gains (Losses) Market Value December 31, 2019 Cash accounts in banking institutions $ 119,272 $ — $ — $ 119,272 Money market accounts 12,355 — — 12,355 U.S. Government bonds — — — — $ 131,627 $ — $ — $ 131,627 December 31, 2018 Cash accounts in banking institutions $ 71,217 $ — $ — $ 71,217 Money market accounts 11,014 — — 11,014 U.S. Government bonds 128,782 9 — 128,791 $ 211,013 $ 9 $ — $ 211,022
Schedule of Short-Term Investments	The following table provides details regarding the Company’s portfolio of short-term investments (in thousands): Amortized Unrealized Aggregate Short-term Investments Classification Cost Gains (Losses) Market Value December 31, 2019 Certificates of deposit $ 700 $ — $ — $ 700 U.S. Government bonds 513,577 190 (6 ) 513,761 $ 514,277 $ 190 $ (6 ) $ 514,461 December 31, 2018 Certificates of deposit $ 500 $ — $ (1 ) $ 499 Corporate Bonds 114,678 1 (19 ) 114,660 U.S. Government bonds 189,202 5 (43 ) 189,164 $ 304,380 $ 6 $ (63 ) $ 304,323

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The following table provides the assets and liabilities carried at fair value measured on a recurring basis as of December 31, 2019 (in thousands): Fair Value Measurements, Using Total Carrying Value as of December 31, 2019 Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents $ 12,355 $ 12,355 $ — $ — Short-term investments 514,461 514,461 — — The following table provides the assets and liabilities carried at fair value measured on a recurring basis as of December 31, 2018 (in thousands): Fair Value Measurements, Using Total Carrying Value as of December 31, 2018 Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents $ 139,805 $ 139,805 $ — $ — Short-term investments 304,323 304,323 — —

INVENTORY (Tables)

INVENTORY (Tables)	12 Months Ended
	Dec. 31, 2019
Inventory Disclosure [Abstract]
Schedule of Inventory	Inventory consisted of the following (in thousands): December 31, 2019 2018 Raw materials $ 25,920 $ 31,203 Work-in-process 7,987 781 Finished goods 30,046 38,016 Inventory $ 63,953 $ 70,000

PROPERTY AND EQUIPMENT (Tables)

PROPERTY AND EQUIPMENT (Tables)	12 Months Ended
	Dec. 31, 2019
Property Plant And Equipment [Abstract]
Property and Equipment	Property and equipment consist of the following (in thousands): December 31, 2019 2018 Land $ 2,642 $ 1,006 Building and improvements 47,994 39,285 Office and lab equipment 74,726 55,333 Furniture, fixtures and computer related assets 7,592 6,941 Construction-in-progress 12,194 12,117 145,148 114,682 Less: Accumulated depreciation (57,276 ) (44,943 ) Property and equipment, net $ 87,872 $ 69,739

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS (Tables)	12 Months Ended
	Dec. 31, 2019
Finite Lived Intangible Assets Net [Abstract]
Schedule of Acquired Technology	These intangible assets consist of the following (in thousands): December 31, 2019 2018 PD-LD, Inc. $ 1,481 $ 1,481 Motorola 15,909 15,909 BASF 95,989 95,989 Fujifilm 109,462 109,462 Other 401 — 223,242 222,841 Less: Accumulated amortization (132,468 ) (111,890 ) Acquired technology, net $ 90,774 $ 110,951
Schedule of Other Intangible Assets	At December 31, 2019, these other intangible assets consist of the following (in thousands): December 31, 2019 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Customer relationships $ 10,520 $ (3,142 ) $ 7,378 Developed IP, processes and recipes 4,820 (1,108 ) 3,712 Trade name/Trademarks 1,500 (518 ) 982 Total identifiable other intangible assets $ 16,840 $ (4,768 ) $ 12,072

LEASES (Tables)

LEASES (Tables)	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Summary of Operating Lease Cost and Supplemental Cash Flow Information Related to Operating Leases	The following table presents the Company’s operating lease cost and supplemental cash flow information related to the Company’s operating leases (in thousands): Year Ended December 31, 2019 Operating lease cost $ 1,855 Non-cash activity: Right-of-use assets obtained in exchange for lease obligations $ 9,776
Schedule of Weighted Average Assumptions Used to Compute Right-of-use Assets and Lease Liabilities	The following table presents weighted average assumptions used to compute the Company’s right-of-use assets and lease liabilities: December 31, 2019 Weighted average remaining lease term (in years) 7.4 Weighted average discount rate 5.5 %
Schedule of Undiscounted Future Minimum Lease Payments Having Non-cancelable Lease Terms	Undiscounted future minimum lease payments as of December 31, 2019, by year and in the aggregate, having non-cancelable lease terms in excess of one year were as follows (in thousands): Maturities of Operating Lease Liabilities 2020 $ 1,958 2021 1,278 2022 1,209 2023 1,070 2024 1,007 Thereafter 3,825 Total lease payments 10,347 Less imputed interest (1,865 ) Present value of lease payments $ 8,482
Schedule of Future Minimum Lease Payments Having Non-cancelable Lease Terms	Future minimum lease payments as of December 31, 2018, by year and in the aggregate, having non-cancelable lease terms in excess of one year were expected to be as follows: Total Minimum Lease Payments 2019 $ 1,652 2020 1,512 2021 833 2022 833 2023 833 Thereafter 4,721 Total lease payments $ 10,384

ACCRUED EXPENSES (Tables)

ACCRUED EXPENSES (Tables)	12 Months Ended
	Dec. 31, 2019
Payables And Accruals [Abstract]
Accrued Expenses	Accrued expenses consist of the following (in thousands): December 31, 2019 2018 Compensation $ 30,295 $ 13,803 Royalties 11,776 6,996 Research and development agreements 3,052 3,572 Consulting 471 527 Professional Fees 268 655 Other 3,160 10,504 Accrued Expenses $ 49,022 $ 36,057

ACCUMULATED OTHER COMPREHENSI_2

ACCUMULATED OTHER COMPREHENSIVE LOSS (Tables)	12 Months Ended
	Dec. 31, 2019
Accumulated Other Comprehensive Income Loss Net Of Tax [Abstract]
Schedule of Accumulated Other Comprehensive Loss	Amounts related to the changes in accumulated other comprehensive loss were as follows (in thousands): Unrealized Gain (Loss) on Available-for- Sale-Securities Net Unrealized Gain (Loss) on Retirement Plan (2) Change in Cumulative Foreign Currency Translation Adjustment Total Affected Line items in the Consolidated Statements of Income Balance January 1, 2017, net of tax $ (246 ) $ (10,355 ) $ (65 ) $ (10,666 ) Other comprehensive loss before reclassification (12 ) (2,184 ) 28 (2,168 ) Reclassification to net income (1) — 1,370 — 1,370 Selling, general and administrative, research and development and cost of sales Change during period (12 ) (814 ) 28 (798 ) Balance December 31, 2017, net of tax (258 ) (11,169 ) (37 ) (11,464 ) Other comprehensive gain (loss) before reclassification 268 (6,690 ) (9 ) (6,431 ) Reclassification to net income (1) — 1,661 — 1,661 Selling, general and administrative, research and development and cost of sales Change during period 268 (5,029 ) (9 ) (4,770 ) Balance December 31, 2018, net of tax 10 (16,198 ) (46 ) (16,234 ) Other comprehensive gain (loss) before reclassification 181 (3,492 ) — (3,311 ) Reclassification to net income (1) — 2,523 25 2,548 Selling, general and administrative, research and development and cost of sales Change during period 181 (969 ) 25 (763 ) Balance December 31, 2019, net of tax $ 191 $ (17,167 ) $ (21 ) $ (16,997 ) (1) The Company reclassified amortization of prior service cost, actuarial loss and plan amendment cost for its retirement plan from accumulated other comprehensive loss to net income of $2.5 million, $1.7 million and $1.4 million for the years ended December 31, 2019, 2018 and 2017, respectively. (2) Refer to Note 15: Employee Retirement Plans

STOCK-BASED COMPENSATION (Table

STOCK-BASED COMPENSATION (Tables)	12 Months Ended
	Dec. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Option Activity	The following table summarizes the stock option activity during the year ended December 31, 2019 for all the grants under the Equity Compensation Plan (in thousands, except share and per share data): Options Weighted Average Exercise Price Outstanding at January 1, 2019 500 $ 10.04 Forfeited/Expired (500 ) 10.04 Outstanding at December 31, 2019 — $ —
Restricted Stock and Units Activity	The following table summarizes the activity related to restricted stock unit (RSU) share based payment awards: Number of Shares Weighted- Average Grant-Date Fair Value Unvested, January 1, 2019 92,381 $ 97.56 Granted 58,549 168.95 Vested (49,635 ) 87.96 Forfeited (2,485 ) 103.79 Unvested, December 31, 2019 98,810 $ 144.53 The following table summarizes the activity related to restricted stock award (RSA) share based payment awards: Number of Shares Weighted- Average Grant-Date Fair Value Unvested, January 1, 2019 409,949 $ 46.74 Granted 73,640 194.19 Vested (171,946 ) 47.89 Unvested, December 31, 2019 311,643 $ 80.94
Schedule of Nonvested Performance-Based Units Activity	The following table summarizes the activity related to performance unit awards (PSU) share based payment awards: Number of Shares Weighted- Average Grant-Date Fair Value Unvested, January 1, 2019 52,730 $ 86.43 Granted 25,746 198.72 Vested (40,695 ) 59.09 Unvested, December 31, 2019 37,781 $ 134.97

EMPLOYEE RETIREMENT PLANS (Tabl

EMPLOYEE RETIREMENT PLANS (Tables)	12 Months Ended
	Dec. 31, 2019
Defined Benefit Pension Plans And Defined Benefit Postretirement Plans Disclosure [Abstract]
Information Relating to the Company's Plan	Information relating to the Company’s plan is as follows (in thousands): Year Ended December 31, 2019 2018 Change in benefit obligation: Benefit obligation, beginning of year $ 44,055 $ 33,176 Service cost 969 1,301 Interest cost 1,613 1,047 Actuarial loss 4,480 8,531 Benefit obligation, end of year 51,117 44,055 Fair value of plan assets — — Unfunded status of the plan, end of year $ 51,117 $ 44,055 Current liability — — Noncurrent liability $ 51,117 $ 44,055
Components of Net Periodic Pension Cost	The components of net periodic pension cost were as follows (in thousands): Year Ended December 31, 2019 2018 2017 Service cost $ 969 $ 1,301 $ 1,214 Interest cost 1,613 1,047 1,013 Amortization of prior service cost 1,595 1,683 1,667 Amortization of loss 1,641 435 457 Total net periodic benefit cost $ 5,818 $ 4,466 $ 4,351
Assumptions Used to Determine Benefit Obligation and Net Periodic Pension Cost	Assumptions used to determine the year end benefit obligation were as follows: Year Ended December 31, 2019 2018 Discount rate 2.64 % 3.82 % Rate of compensation increases 3.50 % 3.50 % Assumptions used to determine the net periodic pension cost were as follows: Year Ended December 31, 2019 2018 2017 Discount rate 3.82 % 3.22 % 3.41 % Rate of compensation increases 3.50 % 3.50 % 3.50 %
Amounts to be Amortized from Accumulated Other Comprehensive Loss into Net Periodic Pension Cost in Next Fiscal Year	The estimated amounts to be amortized from accumulated other comprehensive loss into the net periodic pension cost in 2020 are as follows (in thousands): Amortization of prior service cost $ 1,099 Amortization of loss 2,260 Total $ 3,359
Benefit Payments Expected to be Paid	Benefit payments, which reflect estimated future service, are currently expected to be paid as follows (in thousands): Year Projected Benefits 2020 $ — 2021 3,777 2022 4,288 2023 4,618 2024 4,618 2025-2029 28,400 Thereafter 25,800

CONCENTRATION OF RISK (Tables)

CONCENTRATION OF RISK (Tables)	12 Months Ended
	Dec. 31, 2019
Risks And Uncertainties [Abstract]
Revenues and Accounts Receivable From Our Largest Customers	Revenues and accounts receivable from the Company's largest customers for the years ended December 31, were as follows (in thousands): 2019 2018 2017 Customer % of Total Revenue Accounts Receivable % of Total Revenue Accounts Receivable % of Total Revenue Accounts Receivable A 44% $ 13,830 37% $ 14,419 62% $ 19,588 B 27% 19,346 33% 11,990 24% 17,348 C 15% 10,592 10% 9,071 6% 10,632
Revenues by Geographic Area	Revenues by geographic area are as follows (in thousands): Year Ended December 31, Country 2019 2018 2017 South Korea $ 250,562 $ 171,915 $ 289,418 China 135,259 51,931 24,892 Japan 5,276 6,823 8,542 Other non-U.S. locations 2,270 2,967 2,438 Total non-U.S. locations 393,367 233,636 325,290 United States 11,810 13,778 10,339 Total revenue $ 405,177 $ 247,414 $ 335,629
Long-Lived Assets (Net) by Geographic Area	Long-lived assets (net), by geographic area are as follows (in thousands): 2019 2018 United States $ 80,027 $ 64,560 Other 7,845 5,179 Total long-lived assets $ 87,872 $ 69,739

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Components of Income (Loss) before Income Taxes	The components of income before income taxes are as follows (in thousands): Year ended December 31, 2019 2018 2017 United States $ 53,629 $ 13,565 $ 100,260 Foreign 116,276 50,746 49,277 Income before income taxes $ 169,905 $ 64,311 $ 149,537
Components of Income Tax Expense	The components of the income tax expense are as follows (in thousands): Year ended December 31, 2019 2018 2017 Current income tax expense: Federal $ (20,108 ) $ (9,097 ) $ (5,817 ) State (755 ) (511 ) (54 ) Foreign (16,514 ) (8,677 ) (15,406 ) (37,377 ) (18,285 ) (21,277 ) Deferred income tax benefit (expense): Federal 5,208 12,622 (24,425 ) State 1,054 611 (23 ) Foreign (486 ) (419 ) 73 5,776 12,814 (24,375 ) Income tax expense $ (31,601 ) $ (5,471 ) $ (45,652 )
Reconciliation of the Statutory U.S. Federal Tax Rate to the Effective Tax Rate	Reconciliation of the statutory U.S. federal tax rate to the Company's effective tax rate is as follows: Year ended December 31, 2019 2018 2017 Statutory U.S. federal income tax rate 21.0 % 21.0 % 35.0 % State income taxes, net of federal benefit 0.1 (0.2 ) — Effect of foreign operations (5.4 ) (4.7 ) (7.1 ) Accruals and reserves (1.1 ) — 0.1 Nondeductible employee compensation 2.5 1.7 1.5 Research tax credits (1.4 ) (2.7 ) (0.7 ) Change in valuation allowance — — (4.1 ) Stock based compensation (1.7 ) (2.7 ) (1.9 ) U.S. Tax Cuts and Jobs Act — (3.5 ) 7.7 U.S. International Tax (Sub F, GILTI, FDII) 3.8 (1.2 ) — Other 0.8 0.8 — Effective tax rate 18.6 % 8.5 % 30.5 %
Tax Loss and Tax Credit Carryforwards	The following table summarizes Company tax loss and tax credit carry forwards for tax return purposes at December 31, 2019 (in thousands): Related Tax Deduction Tax Benefit Expiration Date Tax credit carry forwards: State research tax credits n/a $ 3,368 2026 to 2034 Total credit carry forwards n/a $ 3,368
Significant Components of Deferred Tax Assets and Liabilities	Significant components of the Company's net deferred tax assets and liabilities are as follows (in thousands): December 31, 2019 2018 Deferred tax asset: Capitalized technology license $ 560 $ 553 Capitalized research expenditures 3,319 4,710 Accruals and reserves 4,130 2,890 Retirement plan 11,363 9,570 Deferred revenue 14,354 12,028 Tax credit carry forwards 3,997 2,895 Stock-based compensation 1,884 1,701 Other 1,682 47 41,289 34,394 Valuation allowance (3,368 ) (2,893 ) Deferred tax assets 37,921 31,501 Deferred tax liability: Accruals and reserves (7,546 ) (7,124 ) Deferred tax liabilities (7,546 ) (7,124 ) Net deferred tax assets $ 30,375 $ 24,377

REVENUE RECOGNITION (Tables)

REVENUE RECOGNITION (Tables)	12 Months Ended
	Dec. 31, 2019
Schedule of Assets and Liabilities Associated with Contracts from Customers	The following table provides information about assets and liabilities associated with our contracts from customers (in thousands): As of December 31, 2019 Accounts receivable $ 60,452 Short-term unbilled receivables 1,362 Long-term unbilled receivables — Short-term deferred revenue 97,333 Long-term deferred revenue 47,529
Summary of Significant Changes in Unbilled Receivables and Deferred Liabilities Balances	Significant changes in the unbilled receivables and deferred liabilities balances for the years ended December 31, 2019 and 2018, are as follows (in thousands): Year Ended December 31, 2019 Unbilled Receivables Increase (Decrease) Deferred Revenue (Increase) Decrease Balance at December 31, 2018 $ 1,020 $ (122,567 ) Revenue recognized that was previously included in deferred revenue — 133,394 Increases due to cash received — (157,321 ) Cumulative catch-up adjustment arising from changes in estimates of transaction price — 1,632 Unbilled receivables recognized 1,834 — Transferred to receivables from unbilled receivables (1,492 ) — Net change 342 (22,295 ) Balance at December 31, 2019 $ 1,362 $ (144,862 ) Year Ended December 31, 2018 Unbilled Receivables Increase (Decrease) Deferred Revenue (Increase) Decrease Balance at December 31, 2017 $ 70 $ (38,883 ) Adoption of Topic 606 on January 1, 2018 307 (21,307 ) Adjusted balance on January 1, 2018 377 (60,190 ) Revenue recognized that was previously included in deferred revenue — 64,562 Increases due to cash received — (130,639 ) Cumulative catch-up adjustment arising from changes in estimates of transaction price — 3,700 Unbilled receivables recognized 2,024 — Transferred to receivables from unbilled receivables (1,381 ) — Net change 643 (62,377 ) Balance at December 31, 2018 $ 1,020 $ (122,567 )
Revenue from Contracts with Customers - ASU No. 2014-09 [Member]
Summary of Impacts of Adopting Topic 606 on Consolidated Financial Statements	The following tables summarize the impacts of adopting Topic 606 on the Company’s Consolidated Financial Statements for the year ended December 31, 2018 (in thousands) Impact of Changes in Accounting Policies December 31, 2018 As Reported Adjustment Balances Without Adoption of Topic 606 ASSETS Other assets (current and non-current) $ 70,892 $ — $ 70,892 Deferred income taxes 24,377 (11,153 ) 13,224 TOTAL ASSETS 933,424 (11,153 ) 922,271 LIABILITIES AND SHAREHOLDERS' EQUITY Deferred revenue (current and non-current) 122,567 (99,885 ) 22,682 Retained earnings 129,552 88,732 218,284 TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY 933,424 (11,153 ) 922,271 Impact of Changes in Accounting Policies Year Ended December 31, 2018 As Reported Adjustment Balances Without Adoption of Topic 606 REVENUE $ 247,414 $ 78,885 $ 326,299 Gross margin 193,873 78,885 272,758 OPERATING INCOME 56,735 78,885 135,620 INCOME BEFORE INCOME TAXES 64,311 78,885 143,196 INCOME TAX EXPENSE (5,471 ) (7,252 ) (12,723 ) NET INCOME 58,840 71,633 130,473 Impact of Changes in Accounting Policies Year Ended December 31, 2018 As Reported Adjustment Balances Without Adoption of Topic 606 CASH FLOWS FROM OPERATING ACTIVITIES: Net income $ 58,840 $ 71,633 $ 130,473 Amortization of deferred revenue and recognition of unbilled receivables (68,905 ) (81,991 ) (150,896 ) Deferred income tax (benefit) expense (12,814 ) 10,358 (2,456 ) Other assets (current and non-current) (59,062 ) — (59,062 ) Net cash provided by operating activities 121,796 — 121,796

NET INCOME PER COMMON SHARE (Ta

NET INCOME PER COMMON SHARE (Tables)	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Schedule of Earnings Per Share	The following table is a reconciliation of net income and the shares used in calculating basic and diluted net income per common share for the year ended December 31, 2019, 2018 and 2017 (in thousands, except share and per share data): Year Ended December 31, 2019 2018 2015 Numerator: Net income $ 138,304 $ 58,840 $ 103,885 Adjustment for Basic EPS: Earnings allocated to unvested shareholders (1,106 ) (690 ) (1,638 ) Adjusted net income $ 137,198 $ 58,150 $ 102,247 Denominator: Weighted average common shares outstanding – Basic 46,959,775 46,849,588 46,725,289 Effect of dilutive shares: Common stock equivalents arising from stock options and ESPP 1,334 1,956 2,611 Restricted stock awards and units and performance units 34,353 45,222 77,294 Weighted average common shares outstanding – Diluted 46,995,462 46,896,766 46,805,194 Net income per common share: Basic $ 2.92 $ 1.24 $ 2.19 Diluted $ 2.92 $ 1.24 $ 2.18

QUARTERLY SUPPLEMENTAL FINANC_2

QUARTERLY SUPPLEMENTAL FINANCIAL DATA (UNAUDITED) (Tables)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Quarterly Supplemental Financial Data (Unaudited)	Presented below is a summary of the unaudited quarterly financial information for the year ended December 31, 2019 (in thousands, except per share data): Three Months Ended March 31, 2019 June 30, 2019 September 30, 2019 December 31, 2019 Total Revenue $ 87,765 $ 118,168 $ 97,515 $ 101,729 $ 405,177 Net income $ 31,474 $ 43,440 $ 36,962 $ 26,428 $ 138,304 Net income per common share: Basic $ 0.66 $ 0.92 $ 0.78 $ 0.56 $ 2.92 Diluted $ 0.66 $ 0.92 $ 0.78 $ 0.56 $ 2.92 F-37 Presented below is a summary of the unaudited quarterly financial information for the year ended December 31, 201 8 (in thousands, except per share data): Three Months Ended March 31, 2018 June 30, 2018 September 30, 2018 December 31, 2018 Total Revenue $ 43,572 $ 56,149 $ 77,550 $ 70,143 $ 247,414 Net income $ 5,959 $ 10,814 $ 22,818 $ 19,249 $ 58,840 Net income per common share: Basic $ 0.13 $ 0.23 $ 0.48 $ 0.40 $ 1.24 Diluted $ 0.13 $ 0.23 $ 0.48 $ 0.40 $ 1.24

BUSINESS - Additional Informati

BUSINESS - Additional Information (Details)	Dec. 31, 2019patent
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Number of patents issued and pending application	5,000

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Additional Information (Details) - USD ($)	Jun. 28, 2016	Jul. 23, 2012	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018	Dec. 31, 2017
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents maturity period			three months or less
Allowance for doubtful accounts			$ 84,000		$ 77,000	$ 0
Goodwill impairment loss			$ 0
License agreement, extended option term			2 years
License fee agreement, term of agreement			5 years
Recognized income tax positions measured at likelihood of realization description			Recognized income tax positions are measured at the largest amount of which the likelihood of realization is greater than 50%.
Operating lease, right-of-use asset			$ 8,500,000
Operating lease, liabilities			$ 8,482,000
Leases - ASU No. 2016-02 [Member]
Summary Of Significant Accounting Policies [Line Items]
Operating lease, right-of-use asset				$ 8,300,000
Operating lease, liabilities				$ 8,300,000
Patents [Member] | FUJIFILM [Member]
Summary Of Significant Accounting Policies [Line Items]
OLED patents useful life		10 years	10 years
Patents [Member] | BASF [Member]
Summary Of Significant Accounting Policies [Line Items]
OLED patents useful life	10 years		10 years
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Recognized income tax positions measured at percentage of likelihood of realization			50.00%
Minimum [Member] | Other Intangible Assets [Member] | Adesis, Inc. [Member]
Summary Of Significant Accounting Policies [Line Items]
Amortization period of acquired intangible assets (in years)			10 years
Maximum [Member] | Other Intangible Assets [Member] | Adesis, Inc. [Member]
Summary Of Significant Accounting Policies [Line Items]
Amortization period of acquired intangible assets (in years)			15 years
Building [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life (in years)			30 years
Building Improvements [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life (in years)			15 years
Office, Lab Equipment and Furniture and Fixtures [Member] | Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life (in years)			3 years
Office, Lab Equipment and Furniture and Fixtures [Member] | Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life (in years)			7 years
Computer Software [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life (in years)			3 years

CASH, CASH EQUIVALENTS AND IN_3

CASH, CASH EQUIVALENTS AND INVESTMENTS - Schedule of Cash, Cash Equivalents (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Cash And Cash Equivalents [Line Items]
Cash Equivalents, at Carrying Value	$ 131,627	$ 211,013
Cash Equivalents, Gross Unrealized Gains		9
Cash and Cash Equivalents, Fair Value Disclosure	131,627	211,022
Cash Accounts in Banking Institutions [Member]
Cash And Cash Equivalents [Line Items]
Cash Equivalents, at Carrying Value	119,272	71,217
Cash and Cash Equivalents, Fair Value Disclosure	119,272	71,217
Money Market Accounts [Member]
Cash And Cash Equivalents [Line Items]
Cash Equivalents, at Carrying Value	12,355	11,014
Cash and Cash Equivalents, Fair Value Disclosure	$ 12,355	11,014
U.S. Government Bonds [Member]
Cash And Cash Equivalents [Line Items]
Cash Equivalents, at Carrying Value		128,782
Cash Equivalents, Gross Unrealized Gains		9
Cash and Cash Equivalents, Fair Value Disclosure		$ 128,791

CASH, CASH EQUIVALENTS AND IN_4

CASH, CASH EQUIVALENTS AND INVESTMENTS - Schedule of Short-Term Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	$ 514,277	$ 304,380
Available-for-sale Securities, Gross Unrealized Gains	190	6
Available-for-sale Securities, Gross Unrealized Losses	(6)	(63)
Available-for-sale Securities, Fair Value Disclosure	514,461	304,323
Certificates of Deposit [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	700	500
Available-for-sale Securities, Gross Unrealized Losses		(1)
Available-for-sale Securities, Fair Value Disclosure	700	499
Corporate Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis		114,678
Available-for-sale Securities, Gross Unrealized Gains		1
Available-for-sale Securities, Gross Unrealized Losses		(19)
Available-for-sale Securities, Fair Value Disclosure		114,660
U.S. Government Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	513,577	189,202
Available-for-sale Securities, Gross Unrealized Gains	190	5
Available-for-sale Securities, Gross Unrealized Losses	(6)	(43)
Available-for-sale Securities, Fair Value Disclosure	$ 513,761	$ 189,164

CASH, CASH EQUIVALENTS AND IN_5

CASH, CASH EQUIVALENTS AND INVESTMENTS - Additional Information (Details) $ in Millions	Dec. 31, 2019USD ($)Investment
Cash And Cash Equivalents [Abstract]
Number of minority investments | Investment	1
Minority investment, carrying value | $	$ 5

FAIR VALUE MEASUREMENTS - Sched

FAIR VALUE MEASUREMENTS - Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 131,627	$ 211,022
Short-term investments	514,461	304,323
Fair Value, Measurements, Recurring [Member] | Reported Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	12,355	139,805
Short-term investments	514,461	304,323
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	12,355	139,805
Short-term investments	$ 514,461	$ 304,323

FAIR VALUE MEASUREMENTS - Addit

FAIR VALUE MEASUREMENTS - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Other than temporary impairments of investments	$ 0	$ 0

INVENTORY - Schedule of Invento

INVENTORY - Schedule of Inventory (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Raw materials	$ 25,920	$ 31,203
Work-in-process	7,987	781
Finished goods	30,046	38,016
Inventory	$ 63,953	$ 70,000

INVENTORY - Additional Informat

INVENTORY - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Inventory Disclosure [Abstract]
Change in inventory reserve	$ 5,938	$ 3,630	$ 0

PROPERTY AND EQUIPMENT (Details

PROPERTY AND EQUIPMENT (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 145,148	$ 114,682
Less: Accumulated depreciation	(57,276)	(44,943)
Property and equipment, net	87,872	69,739
Land [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	2,642	1,006
Building and improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	47,994	39,285
Office and lab equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	74,726	55,333
Furniture and fixtures [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	7,592	6,941
Construction-in-progress [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 12,194	$ 12,117

PROPERTY AND EQUIPMENT - Additi

PROPERTY AND EQUIPMENT - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)ft²	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 12,456	$ 8,612	$ 4,919
Ewing, New Jersey Properties [Member]
Property, Plant and Equipment [Line Items]
Area of facility acquired | ft²	88,000
Cost of facility acquired	$ 8,200

GOODWILL AND INTANGIBLE ASSET_2

GOODWILL AND INTANGIBLE ASSETS - Schedule of Acquired Technology (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Acquired technology, gross	$ 223,242	$ 222,841
Less: Accumulated amortization	(132,468)	(111,890)
Acquired technology, net	90,774	110,951
PD LD, Inc [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired technology, gross	1,481	1,481
Motorola [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired technology, gross	15,909	15,909
BASF [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired technology, gross	95,989	95,989
FUJIFILM [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired technology, gross	109,462	$ 109,462
Other [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired technology, gross	$ 401

GOODWILL AND INTANGIBLE ASSET_3

GOODWILL AND INTANGIBLE ASSETS - Acquired Technology - Additional Information (Details) € in Millions	Jun. 28, 2016USD ($)patent	Jun. 28, 2016EUR (€)patent	Jul. 23, 2012USD ($)patent	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Finite-Lived Intangible Assets [Line Items]
Amortization related to acquired technology				$ 21,962,000	$ 21,962,000	$ 21,983,000
Future amortization expense, 2020				20,600,000
Future amortization expense, 2021				20,600,000
Future amortization expense, 2022				15,800,000
Future amortization expense, 2023				9,700,000
Future amortization expense, 2024				9,600,000
Future amortization expense, thereafter				14,500,000
Patent Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization related to acquired technology				$ 20,600,000	$ 20,600,000	$ 20,600,000
Patents [Member] | FUJIFILM [Member]
Finite-Lived Intangible Assets [Line Items]
Number of patents acquired (more than) | patent			1,200
Assigned value of acquired intangible assets			$ 105,000,000
Cash paid for OLED patents			$ 4,500,000
OLED patents useful life			10 years	10 years
Patents [Member] | BASF [Member]
Finite-Lived Intangible Assets [Line Items]
Number of patents acquired (more than) | patent	500	500
Assigned value of acquired intangible assets	$ 95,800,000	€ 86.8
Cash paid for OLED patents	$ 217,000
OLED patents useful life	10 years	10 years		10 years

GOODWILL AND INTANGIBLE ASSET_4

GOODWILL AND INTANGIBLE ASSETS - Other Intangible Assets - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 15,535	$ 15,535
Adesis, Inc. [Member]
Finite-Lived Intangible Assets [Line Items]
Other intangible assets	16,840
Amortization expense related to other intangible assets	1,400	$ 1,400	$ 1,400
Future amortization expense of other intangible assets, fiscal year 2020	1,400
Future amortization expense of other intangible assets, fiscal year 2021	1,400
Future amortization expense of other intangible assets, fiscal year 2022	1,400
Future amortization expense of other intangible assets, fiscal year 2023	1,400
Future amortization expense of other intangible assets, fiscal year 2024	1,400
Future amortization expense of other intangible assets, thereafter	5,100
Goodwill	15,500
Adesis, Inc. [Member] | Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Other intangible assets	$ 10,520
Weighted average useful life , intangible assets	11 years 6 months
Adesis, Inc. [Member] | Internally-developed IP, Processes and Recipes [Member]
Finite-Lived Intangible Assets [Line Items]
Other intangible assets	$ 4,820
Weighted average useful life , intangible assets	15 years
Adesis, Inc. [Member] | Trade Name/Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Other intangible assets	$ 1,500
Weighted average useful life , intangible assets	10 years

GOODWILL AND INTANGIBLE ASSET_5

GOODWILL AND INTANGIBLE ASSETS - Schedule of Other Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Accumulated Amortization	$ (4,768)	$ (3,384)
Net Carrying Amount	12,072	$ 13,456
Adesis, Inc. [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	16,840
Accumulated Amortization	(4,768)
Net Carrying Amount	12,072
Adesis, Inc. [Member] | Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	10,520
Accumulated Amortization	(3,142)
Net Carrying Amount	7,378
Adesis, Inc. [Member] | Developed IP, Processes and Recipes [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	4,820
Accumulated Amortization	(1,108)
Net Carrying Amount	3,712
Adesis, Inc. [Member] | Trade Name/Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,500
Accumulated Amortization	(518)
Net Carrying Amount	$ 982

LEASES- Additional Information

LEASES- Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Lessee Lease Description [Line Items]
Operating lease description	The Company used the incremental borrowing rate on January 1, 2019 for operating leases that commenced prior to that date. Current lease agreements do not contain any residual value guarantees or material restrictive covenants. As of December 31, 2019, the Company did not have any finance leases and no additional operating leases that have not yet commenced.
Operating lease, option to extend	true
Operating lease, right-of-use asset	$ 8,500
Operating lease liabilities current	1,600
Long-term operating lease liabilities	6,900
Operating lease cost	$ 1,855	$ 1,700	$ 972,000
Minimum [Member]
Lessee Lease Description [Line Items]
Operating leases remaining term	1 year
Maximum [Member]
Lessee Lease Description [Line Items]
Operating leases remaining term	9 years

LEASES - Summary of Operating L

LEASES - Summary of Operating Lease Cost and Supplemental Cash Flow Information Related to Operating Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Leases [Abstract]
Operating lease cost	$ 1,855	$ 1,700	$ 972,000
Non-cash activity:
Right-of-use assets obtained in exchange for lease obligations	$ 9,776

LEASES - Schedule of Weighted A

LEASES - Schedule of Weighted Average Assumptions Used to Compute Right-of-use Assets and Lease Liabilities (Details)	Dec. 31, 2019
Leases [Abstract]
Weighted average remaining lease term (in years)	7 years 4 months 24 days
Weighted average discount rate	5.50%

LEASES - Schedule of Undiscount

LEASES - Schedule of Undiscounted Future Minimum Lease Payments Having Non-cancelable Lease Terms (Details) $ in Thousands	Dec. 31, 2019USD ($)
Leases [Abstract]
2020	$ 1,958
2021	1,278
2022	1,209
2023	1,070
2024	1,007
Thereafter	3,825
Total lease payments	10,347
Less imputed interest	(1,865)
Present value of lease payments	$ 8,482

LEASES - Schedule of Future Min

LEASES - Schedule of Future Minimum Lease Payments Having Non-cancelable Lease Terms (Details) $ in Thousands	Dec. 31, 2019USD ($)
Leases [Abstract]
2019	$ 1,652
2020	1,512
2021	833
2022	833
2023	833
Thereafter	4,721
Total lease payments	$ 10,384

ACCRUED EXPENSES - Accrued Expe

ACCRUED EXPENSES - Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Payables And Accruals [Abstract]
Compensation	$ 30,295	$ 13,803
Royalties	11,776	6,996
Research and development agreements	3,052	3,572
Consulting	471	527
Professional Fees	268	655
Other	3,160	10,504
Accrued Expenses	$ 49,022	$ 36,057

RESEARCH AND LICENSE AGREEMEN_2

RESEARCH AND LICENSE AGREEMENTS WITH PRINCETON UNIVERSITY, UNIVERSITY OF SOUTHERN CALIFORNIA AND THE UNIVERSITY OF MICHIGAN - Additional Information (Details) - USD ($)	May 01, 2017	Jun. 01, 2013	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019	Apr. 30, 2009	Apr. 30, 2013	Oct. 31, 2017	Apr. 30, 2013	Jul. 31, 2007
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Royalty expense			$ 11,776,000	$ 6,996,000	$ 9,739,000
1997 Research Agreement [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Term of agreement (in years)											10 years
2006 Research Agreement - Original Term [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Term of agreement (in years)							3 years	4 years
Research and development expense incurred										$ 5,000,000
2006 Research Agreement - Extended Term [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Term of agreement (in years)		4 years
Research and development expense incurred									$ 4,600,000
2006 Research Agreement - Extended Term Three [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Term of agreement (in years)	3 years
Research and development expense incurred						$ 2,600,000
Maximum obligation			$ 1,800,000			$ 1,800,000
1997 Amended License Agreement [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Royalty rate for licensed products sold by the Company (in hundredths)			3.00%
Royalty rate for licensed products sold by the Company's sublicenses (in hundredths)			3.00%
Minimum royalty payment per year			$ 100,000
Royalty expense			11,800,000	$ 7,000,000	$ 9,700,000
Minimum investment per year			$ 800,000

EQUITY AND CASH COMPENSATION _2

EQUITY AND CASH COMPENSATION UNDER THE PPG AGREEMENTS - Additional Information (Details) - USD ($)	6 Months Ended		12 Months Ended
	Mar. 31, 2018	Sep. 30, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Long-term Purchase Commitment [Line Items]
Percent of services payable in cash or shares			50.00%
Issuance of common stock in connection with materials and license agreements (in shares)			0	0	0
New OLED Materials Agreement and OLED Materials Agreement [Member] | Cash Distribution
Long-term Purchase Commitment [Line Items]
Charges to expense for cash portion of reimbursement of expenses			$ 1,400,000	$ 771,000	$ 1,700,000
New OLED Materials Agreement and OLED Materials Agreement [Member] | Weighted Average
Long-term Purchase Commitment [Line Items]
Minimum average closing price of common stock (in dollars per share)	$ 20	$ 20

SHAREHOLDERS' EQUITY - Addition

SHAREHOLDERS' EQUITY - Additional Information (Details)	Feb. 18, 2020$ / shares	Dec. 31, 2019USD ($)board_member$ / sharesshares	Dec. 31, 2018USD ($)$ / sharesshares	Dec. 31, 2017$ / shares	Dec. 31, 1995shares
Class Of Stock [Line Items]
Preferred Stock, shares authorized ( in shares)		5,000,000	5,000,000
Preferred Stock, par value (in dollars per share) | $ / shares		$ 0.01	$ 0.01
Number of board members elected by class A shareholders | board_member		2
Common Stock, shares authorized (in shares)		200,000,000	200,000,000
Common Stock, par value (in dollars per share) | $ / shares		$ 0.01	$ 0.01
Common Stock, shares issued (in shares)		48,852,193	48,681,524
Common Stock, shares outstanding (in shares)		47,486,545	47,319,887
Treasury stock repurchased shares		4,011	3,774
Treasury stock aggregate purchase price value | $		$ 649,000	$ 477,000
Common stock dividends declared per share | $ / shares		$ 0.40	$ 0.24	$ 0.12
Common stock dividends paid per share | $ / shares		$ 0.40
Common stock dividends paid | $		$ 18,900,000
Subsequent Event [Member]
Class Of Stock [Line Items]
Common stock dividends declared per share | $ / shares	$ 0.15
Dividend declared date	Feb. 18, 2020
Dividend payable date	Mar. 31, 2020
Dividend record date	Mar. 17, 2020
Series A Nonconvertible Preferred Stock [Member]
Class Of Stock [Line Items]
Preferred Stock, shares issued (in shares)		200,000	200,000		200,000
Preferred Stock, liquidation value per share (in dollars per share) | $ / shares		$ 7.50	$ 7.50
Preferred stock voting rights		Holders of the Series A shares are entitled to one vote per share on matters which shareholders are generally entitled to vote.
Preferred Stock, shares outstanding (in shares)		200,000	200,000

SHAREHOLDERS' EQUITY - Deferred

SHAREHOLDERS' EQUITY - Deferred Compensation Arrangement - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Non-Employee Members of Scientific Advisory Board [Member]
Deferred Compensation Arrangement with Employees and Non-Employees, Share-Based Payments [Line Items]
Shares issued (in shares)	1,960	2,456
Members of Scientific Advisory Board [Member]
Deferred Compensation Arrangement with Employees and Non-Employees, Share-Based Payments [Line Items]
Fair value of shares issued	$ 300,000	$ 300,000

ACCUMULATED OTHER COMPREHENSI_3

ACCUMULATED OTHER COMPREHENSIVE LOSS - Schedule of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
BALANCE		$ 690,506	$ 659,054	$ 528,468
Other comprehensive gain (loss) before reclassification		(3,311)	(6,431)	(2,168)
Reclassification to net income	[1]	2,548	1,661	1,370
TOTAL OTHER COMPREHENSIVE LOSS		(763)	(4,770)	(798)
BALANCE		811,449	690,506	659,054
Unrealized gain (loss) on available-for-sale securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
BALANCE		10	(258)	(246)
Other comprehensive gain (loss) before reclassification		181	268	(12)
TOTAL OTHER COMPREHENSIVE LOSS		181	268	(12)
BALANCE		191	10	(258)
Net unrealized gain (loss) on retirement plan [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
BALANCE	[2]	(16,198)	(11,169)	(10,355)
Other comprehensive gain (loss) before reclassification	[2]	(3,492)	(6,690)	(2,184)
Reclassification to net income	[1],[2]	2,523	1,661	1,370
TOTAL OTHER COMPREHENSIVE LOSS	[2]	(969)	(5,029)	(814)
BALANCE	[2]	(17,167)	(16,198)	(11,169)
Change in cumulative foreign currency translation adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
BALANCE		(46)	(37)	(65)
Other comprehensive gain (loss) before reclassification			(9)	28
Reclassification to net income	[1]	25
TOTAL OTHER COMPREHENSIVE LOSS		25	(9)	28
BALANCE		(21)	(46)	(37)
Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
BALANCE		(16,234)	(11,464)	(10,666)
TOTAL OTHER COMPREHENSIVE LOSS		(763)	(4,770)	(798)
BALANCE		$ (16,997)	$ (16,234)	$ (11,464)
[1]	The Company reclassified amortization of prior service cost, actuarial loss and plan amendment cost for its retirement plan from accumulated other comprehensive loss to net income of $2.5 million, $1.7 million and $1.4 million for the years ended December 31, 2019, 2018 and 2017, respectively.
[2]	Refer to Note 15: Employee Retirement Plans

ACCUMULATED OTHER COMPREHENSI_4

ACCUMULATED OTHER COMPREHENSIVE LOSS - Schedule of Accumulated Other Comprehensive Loss (Parenthetical) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income Loss Net Of Tax [Abstract]
Reclassification to net income	[1]	$ 2,548	$ 1,661	$ 1,370
[1]	The Company reclassified amortization of prior service cost, actuarial loss and plan amendment cost for its retirement plan from accumulated other comprehensive loss to net income of $2.5 million, $1.7 million and $1.4 million for the years ended December 31, 2019, 2018 and 2017, respectively.

STOCK-BASED COMPENSATION - Equi

STOCK-BASED COMPENSATION - Equity Compensation Plan - Additional Information (Details) - Equity Compensation Plan [Member]	12 Months Ended
	Dec. 31, 2019shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)	10,500,000
Number of shares available for grant (in shares)	2,248,573
Compensation plan extended term description	extended the term of the plan through 2024
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration term (in years)	10 years

STOCK-BASED COMPENSATION - Stoc

STOCK-BASED COMPENSATION - Stock Option Activity (Details)	12 Months Ended
	Dec. 31, 2019$ / sharesshares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options, Outstanding at January 1, 2019 | shares	500
Options, Forfeited/ Expired | shares	(500)
Weighted Average Exercise Price, Outstanding at January 1, 2019 | $ / shares	$ 10.04
Weighted Average Exercise Price, Forfeited/ Expired | $ / shares	$ 10.04

STOCK-BASED COMPENSATION - St_2

STOCK-BASED COMPENSATION - Stock Options - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Granted (in shares)	0	0	0
Total intrinsic value of stock options exercised	$ 0	$ 0	$ 146,000
Compensation expense	$ 0	$ 0	$ 0
Shares tendered to net share settle (in shares)	0	0	0

STOCK-BASED COMPENSATION - Eq_2

STOCK-BASED COMPENSATION - Equity Instruments Other Than Options (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Unvested, January 1, 2019	92,381
Number of Shares, Granted	58,549
Number of Shares, Vested	(49,635)
Number of Shares, Forfeited	(2,485)
Number of Shares, Unvested, December 31, 2019	98,810	92,381
Weighted-Average Grant-Date Fair Value, Unvested, January 1, 2019	$ 97.56
Weighted-Average Grant-Date Fair Value, Granted	168.95	$ 115.48	$ 116.58
Weighted-Average Grant-Date Fair Value, Vested	87.96
Weighted-Average Grant-Date Fair Value, Forfeited	103.79
Weighted-Average Grant-Date Fair Value, Unvested, December 31, 2019	$ 144.53	$ 97.56
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Unvested, January 1, 2019	409,949
Number of Shares, Granted	73,640
Number of Shares, Vested	(171,946)
Number of Shares, Unvested, December 31, 2019	311,643	409,949
Weighted-Average Grant-Date Fair Value, Unvested, January 1, 2019	$ 46.74
Weighted-Average Grant-Date Fair Value, Granted	194.19	$ 122.15	83.25
Weighted-Average Grant-Date Fair Value, Vested	47.89
Weighted-Average Grant-Date Fair Value, Unvested, December 31, 2019	$ 80.94	$ 46.74
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Unvested, January 1, 2019	52,730
Number of Shares, Granted	25,746
Number of Shares, Vested	(40,695)
Number of Shares, Unvested, December 31, 2019	37,781	52,730
Weighted-Average Grant-Date Fair Value, Unvested, January 1, 2019	$ 86.43
Weighted-Average Grant-Date Fair Value, Granted	198.72	$ 119.62	$ 105.65
Weighted-Average Grant-Date Fair Value, Vested	59.09
Weighted-Average Grant-Date Fair Value, Unvested, December 31, 2019	$ 134.97	$ 86.43

STOCK-BASED COMPENSATION - Eq_3

STOCK-BASED COMPENSATION - Equity Instruments Other Than Options - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 0	$ 0	$ 0
Fair value of shares withheld for tax withholding obligations	$ 15,980,000	$ 11,620,000	9,432,000
Non Employee Members of Scientific Advisory Board [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued (in shares)	1,960	2,456
Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock awards and units vesting terms	1 year
Fair value of shares issued	$ 916,000,000	$ 4,300,000	$ 1,600,000
Shares issued (in shares)	9,332	25,000	27,500
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant-date fair value of RSU awards granted (in dollars per share)	$ 168.95	$ 115.48	$ 116.58
Fair value as of the respective vesting dates	$ 7,700,000	$ 8,100,000	$ 8,300,000
Grants in period (shares)	58,549
Restricted Stock Units (RSUs) [Member] | Research and Development Expense [Member] | Non Employee Members of Scientific Advisory Board [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 632,000	$ 64,000	$ 976,000
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant-date fair value of RSU awards granted (in dollars per share)	$ 194.19	$ 122.15	$ 83.25
Fair value as of the respective vesting dates	$ 28,400,000	$ 17,700,000	$ 14,800,000
Shares withheld for employee taxes (shares)	86,075	86,679	89,661
Shares withheld for employee taxes	$ 14,000,000	$ 9,200,000	$ 7,800,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$ 30,000,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	2 years 3 months
Grants in period (shares)	73,640
Unrecognized compensation expense related to performance unit awards	$ 30,000,000
Restricted Stock [Member] | Selling, General and Administrative Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	10,000,000	7,600,000	8,500,000
Restricted Stock [Member] | Manufacturing Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	1,100,000	758,000	443,000
Restricted Stock [Member] | Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 2,500,000	$ 2,000,000	$ 1,600,000
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant-date fair value of RSU awards granted (in dollars per share)	$ 198.72	$ 119.62	$ 105.65
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$ 2,700,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	1 year 10 months 13 days
Grants in period (shares)	25,746
Shares withheld for tax withholding obligations (in shares)	16,668	25,208	19,217
Fair value of shares withheld for tax withholding obligations	$ 2,600,000	$ 2,900,000	$ 1,600,000
Unrecognized compensation expense related to performance unit awards	$ 2,700,000
Performance Shares [Member] | Incremental Performance Based [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (shares)	10,096	40,601	24,664
Performance Shares [Member] | Performance-Based Vesting Requirement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (shares)	5,050	6,022	7,817
Performance Shares [Member] | Market-Based Vesting Requirement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (shares)	5,046	6,025	7,821
Performance Shares [Member] | Company Performance-Based Vesting Requirement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (shares)	15,650	28,554	9,026
Performance Shares [Member] | Selling, General and Administrative Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 1,700,000	$ 1,300,000	$ 1,200,000
Performance Shares [Member] | Manufacturing Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	208,000	141,000	119,000
Performance Shares [Member] | Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 419,000	$ 330,000	$ 276,000

STOCK-BASED COMPENSATION - Empl

STOCK-BASED COMPENSATION - Employee Stock Purchase Plan - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jun. 25, 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Proceeds from common stock issued	$ 1,159,000	$ 1,090,000	$ 944,000
Employee Stock Purchase Plan (ESPP) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reserved for issuance (in shares)				1,000,000
Purchase period (in months)	3 months
Percentage of market value (in hundredths)	85.00%
Maximum allocation of base compensation (in hundredths)	10.00%
Maximum shares per purchase date (in shares)	12,500
Maximum value per calendar year, per employee	$ 25,000
Common stock issued (in shares)	7,492	10,303	9,730
Proceeds from common stock issued	$ 889,000	$ 798,000	$ 734,000
Employee Stock Purchase Plan (ESPP) [Member] | Selling, General and Administrative Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Charges to expense	79,000	82,000	69,000
Employee Stock Purchase Plan (ESPP) [Member] | Cost of Sales [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Charges to expense	73,000	81,000	46,000
Employee Stock Purchase Plan (ESPP) [Member] | Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Charges to expense	$ 118,000	$ 130,000	$ 94,000

EMPLOYEE RETIREMENT PLANS - Add

EMPLOYEE RETIREMENT PLANS - Additional Information (Details)	12 Months Ended
	Dec. 31, 2019USD ($)participantmultipledenominator	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Defined Benefit Plan Disclosure [Line Items]
Maximum contribution percentage (in hundredths)	90.00%
Matching contribution limit (in hundredths)	3.00%
Contributions to the 401(k) Plan	$ 880,000	$ 1,200,000	$ 601,000
Initial prior service cost for retirement plan			$ 280,000
Prior service cost expected to be amortized in next fiscal year	$ 1,099,000
Supplemental Executive Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of participants | participant	7
Factor used to determine annual base salary | multiple	12
Annual base salary period (in months)	24 months
Age of participant (in years)	65 years
Minimum period of service (in years)	20 years
Benefit percentage, tier one (in hundredths)	50.00%
Benefit percentage, tier two (in hundredths)	25.00%
Benefit percentage, tier three (in hundredths)	15.00%
Minimum period of service for prorated benefit (in years)	15 years
Factor used to determine prorated benefit | denominator	20
Installment period (in years)	10 years
Benefit percentage for special participants (in hundredths)	50.00%
Initial prior service cost for retirement plan	$ 21,700,000
Prior service cost expected to be amortized in next fiscal year	3,400,000
Accumulated benefit obligation	$ 48,100,000	$ 41,300,000
Defined benefit plan threshold of benefit obligation at which actuarial losses are amortized (in hundredths)	10.00%

EMPLOYEE RETIREMENT PLANS - Inf

EMPLOYEE RETIREMENT PLANS - Information Relating to the Company's Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Change in benefit obligation:
Benefit obligation, beginning of year	$ 44,055	$ 33,176
Service cost	969	1,301
Interest cost	1,613	1,047
Actuarial loss	4,480	8,531
Benefit obligation, end of year	51,117	44,055
Unfunded status of the plan, end of year	51,117	44,055
Noncurrent liability	$ 51,117	$ 44,055

EMPLOYEE RETIREMENT PLANS - Com

EMPLOYEE RETIREMENT PLANS - Components of Net Periodic Pension Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Components of net periodic pension cost [Abstract]
Service cost	$ 969	$ 1,301
Interest cost	1,613	1,047
Supplemental Executive Retirement Plan [Member]
Components of net periodic pension cost [Abstract]
Service cost	969	1,301	$ 1,214
Interest cost	1,613	1,047	1,013
Amortization of prior service cost	1,595	1,683	1,667
Amortization of loss	1,641	435	457
Total net periodic benefit cost	$ 5,818	$ 4,466	$ 4,351

EMPLOYEE RETIREMENT PLANS - Ass

EMPLOYEE RETIREMENT PLANS - Assumptions Used to Determine Benefit Obligation (Details)	Dec. 31, 2019	Dec. 31, 2018
Assumptions used to determine the year end benefit obligation [Abstract]
Discount rate	2.64%	3.82%
Rate of compensation increases	3.50%	3.50%

EMPLOYEE RETIREMENT PLANS - A_2

EMPLOYEE RETIREMENT PLANS - Assumptions Used to Determine Net Periodic Pension Cost (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Assumptions used to determine the net periodic pension cost [Abstract]
Discount rate	3.82%	3.22%	3.41%
Rate of compensation increases	3.50%	3.50%	3.50%

EMPLOYEE RETIREMENT PLANS - Amo

EMPLOYEE RETIREMENT PLANS - Amounts to be Amortized from Accumulated Other Comprehensive Loss into Net Periodic Pension Cost in Next Fiscal Year (Details) $ in Thousands	Dec. 31, 2019USD ($)
Estimated amounts to be amortized from accumulated other comprehensive loss in next fiscal year [Abstract]
Amortization of prior service cost	$ 1,099
Amortization of loss	2,260
Total	$ 3,359

EMPLOYEE RETIREMENT PLANS - Ben

EMPLOYEE RETIREMENT PLANS - Benefit Payments Expected to be Paid (Details) $ in Thousands	Dec. 31, 2019USD ($)
Benefit payments currently expected to be paid [Abstract]
2021	$ 3,777
2022	4,288
2023	4,618
2024	4,618
2025-2029	28,400
Thereafter	$ 25,800

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - Additional Information (Details)	Dec. 31, 2019USD ($)multipleexecutive_officerEmployee	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Loss Contingencies [Line Items]
Purchase commitments for inventory | $	$ 22,000,000	$ 15,900,000	$ 14,200,000
Commitment With Executive Officers [Member]
Loss Contingencies [Line Items]
Number of executive officers under agreement | executive_officer	6
Number of employees under agreement | Employee	2
Multiple of sum of average annual base salary and bonus agreement terms | multiple	2

CONCENTRATION OF RISK - Revenue

CONCENTRATION OF RISK - Revenues and Accounts Receivable From Our Largest Customers (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Concentration Risk [Line Items]
Accounts Receivable	$ 60,452	$ 43,129
Major Customer A [Member] | Total Revenue [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
% of Total Revenue	44.00%	37.00%	62.00%
Major Customer A [Member] | Accounts Receivable [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Accounts Receivable	$ 13,830	$ 14,419	$ 19,588
Major Customer B [Member] | Total Revenue [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
% of Total Revenue	27.00%	33.00%	24.00%
Major Customer B [Member] | Accounts Receivable [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Accounts Receivable	$ 19,346	$ 11,990	$ 17,348
Major Customer C [Member] | Total Revenue [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
% of Total Revenue	15.00%	10.00%	6.00%
Major Customer C [Member] | Accounts Receivable [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Accounts Receivable	$ 10,592	$ 9,071	$ 10,632

CONCENTRATION OF RISK - Additio

CONCENTRATION OF RISK - Additional Information (Details) - supplier	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Supplier Concentration Risk [Member]
Concentration Risk [Line Items]
Number of suppliers from which chemical materials were purchased	1
Excluding North America [Member] | Total Revenue [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration risk, percentage (less than 1% for contracts with U.S. government agencies)	97.00%	94.00%	97.00%

CONCENTRATION OF RISK - Reven_2

CONCENTRATION OF RISK - Revenues by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Concentration Risk [Line Items]
Revenues	$ 101,729	$ 97,515	$ 118,168	$ 87,765	$ 70,143	$ 77,550	$ 56,149	$ 43,572	$ 405,177	$ 247,414	$ 335,629
South Korea [Member]
Concentration Risk [Line Items]
Revenues									250,562	171,915	289,418
China [Member]
Concentration Risk [Line Items]
Revenues									135,259	51,931	24,892
Japan [Member]
Concentration Risk [Line Items]
Revenues									5,276	6,823	8,542
Other Non-U.S. Locations [Member]
Concentration Risk [Line Items]
Revenues									2,270	2,967	2,438
Total Non-U.S. Locations [Member]
Concentration Risk [Line Items]
Revenues									393,367	233,636	325,290
United States [Member]
Concentration Risk [Line Items]
Revenues									$ 11,810	$ 13,778	$ 10,339

CONCENTRATION OF RISK - Long-Li

CONCENTRATION OF RISK - Long-Lived Assets (Net) by Geographic Area (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Total long-lived assets	$ 87,872	$ 69,739
United States [Member]
Segment Reporting Information [Line Items]
Total long-lived assets	80,027	64,560
Other [Member]
Segment Reporting Information [Line Items]
Total long-lived assets	$ 7,845	$ 5,179

INCOME TAXES - Components of In

INCOME TAXES - Components of Income (Loss) before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Components of income before income taxes [Abstract]
United States	$ 53,629	$ 13,565	$ 100,260
Foreign	116,276	50,746	49,277
INCOME BEFORE INCOME TAXES	$ 169,905	$ 64,311	$ 149,537

INCOME TAXES - Components of _2

INCOME TAXES - Components of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current income tax expense:
Federal	$ (20,108)	$ (9,097)	$ (5,817)
State	(755)	(511)	(54)
Foreign	(16,514)	(8,677)	(15,406)
Current income tax benefit (expense)	(37,377)	(18,285)	(21,277)
Deferred income tax benefit (expense):
Federal	5,208	12,622	(24,425)
State	1,054	611	(23)
Foreign	(486)	(419)	73
Deferred income tax expense, gross	5,776	12,814	(24,375)
Income tax expense	$ (31,601)	$ (5,471)	$ (45,652)

INCOME TAXES - Reconciliation o

INCOME TAXES - Reconciliation of the Statutory U.S. Federal Tax Rate to the Effective Tax Rate (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Effective Income Tax Rate Continuing Operations Tax Rate Reconciliation [Abstract]
Statutory U.S. federal income tax rate	21.00%	21.00%	35.00%
State income taxes, net of federal benefit	0.10%	(0.20%)
Effect of foreign operations	(5.40%)	(4.70%)	(7.10%)
Accruals and reserves	(1.10%)		0.10%
Nondeductible employee compensation	2.50%	1.70%	1.50%
Research tax credits	(1.40%)	(2.70%)	(0.70%)
Change in valuation allowance			(4.10%)
Stock based compensation	(1.70%)	(2.70%)	(1.90%)
U.S. Tax Cuts and Jobs Act		(3.50%)	7.70%
U.S. International Tax (Sub F, GILTI, FDII)	3.80%	(1.20%)
Other	0.80%	0.80%
Effective tax rate	18.60%	8.50%	30.50%

INCOME TAXES - Tax Loss and Tax

INCOME TAXES - Tax Loss and Tax Credit Carryforwards (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Tax Credit And Operating Loss Carryforwards [Line Items]
Total credit carry forwards, Tax Benefit	$ 3,368
Research Tax Credit [Member] | State [Member]
Tax Credit And Operating Loss Carryforwards [Line Items]
Total credit carry forwards, Tax Benefit	$ 3,368
Research Tax Credit [Member] | State [Member] | Minimum [Member]
Tax Credit And Operating Loss Carryforwards [Line Items]
Tax credit carryforwards, Expiration Date	Dec. 31, 2026
Research Tax Credit [Member] | State [Member] | Maximum [Member]
Tax Credit And Operating Loss Carryforwards [Line Items]
Tax credit carryforwards, Expiration Date	Dec. 31, 2034

INCOME TAXES - Significant Comp

INCOME TAXES - Significant Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax asset:
Capitalized technology license	$ 560	$ 553
Capitalized research expenditures	3,319	4,710
Accruals and reserves	4,130	2,890
Retirement plan	11,363	9,570
Deferred revenue	14,354	12,028
Tax credit carry forwards	3,997	2,895
Stock-based compensation	1,884	1,701
Other	1,682	47
Deferred Tax Assets, Gross	41,289	34,394
Valuation allowance	(3,368)	(2,893)
Deferred tax assets	37,921	31,501
Deferred tax liability:
Accruals and reserves	(7,546)	(7,124)
Deferred tax liabilities	(7,546)	(7,124)
Net deferred tax assets	$ 30,375	$ 24,377

INCOME TAXES - Additional Infor

INCOME TAXES - Additional Information (Details) - USD ($) $ in Thousands	Oct. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes [Line Items]
Long-term asset		$ 86,090	$ 64,526
Withholding and interest for licencing and royalty payments	$ 13,200
Withholding and interest for licencing and royalty payments period	3 years
Current income tax expense		$ 16,514	8,677	$ 15,406
State and foreign income tax returns subject to examination period minimum (in years)		3 years
State and foreign income tax returns subject to examination period maximum (in years)		4 years
Reduction of Korean Withholding Taxes [Member]
Income Taxes [Line Items]
Reduction of deferred tax asset for foreign tax credits and R&D		$ 20,700	20,700
Korean Government [Member]
Income Taxes [Line Items]
Estimated settlement amounts due (refunds) from withholding taxes			(36,900)
U.S.Federal Government [Member]
Income Taxes [Line Items]
Estimated settlement amounts due (refunds) from withholding taxes			16,200
South Korea [Member]
Income Taxes [Line Items]
Current income tax expense		14,900	14,900	$ 17,600
Allocation of Withholding to Non-Korean Patents [Member]
Income Taxes [Line Items]
Long-term asset		26,900	13,600
Allocation of Withholding to Non-Korean Patents [Member] | U.S.Federal Government [Member]
Income Taxes [Line Items]
Estimated settlement amounts due (refunds) from withholding taxes		$ 25,700	$ 7,700

REVENUE RECOGNITION - Additiona

REVENUE RECOGNITION - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation Of Revenue [Line Items]
Contract expiration year									2022
Backlog associated with committed purchase orders from customers	$ 6,500								$ 6,500
Cumulative effect adjustment to reduction of retained earnings											$ (17,100)
Revenue	$ 101,729	$ 97,515	$ 118,168	$ 87,765	$ 70,143	$ 77,550	$ 56,149	$ 43,572	$ 405,177	$ 247,414	$ 335,629
Revenue from Contracts with Customers - ASU No. 2014-09 [Member]
Disaggregation Of Revenue [Line Items]
Percentage of revenue recorded from sales of materials									97.00%	95.00%	97.00%
Cumulative effect adjustment to reduction of retained earnings					$ (17,100)					$ (17,100)
Revenue										$ 78,900
Revenue from Contracts with Customers - ASU No. 2014-09 [Member] | Adesis, Inc. [Member]
Disaggregation Of Revenue [Line Items]
Percentage of revenue recorded from provision of services									3.00%	5.00%	3.00%

REVENUE RECOGNITION - Schedule

REVENUE RECOGNITION - Schedule of Assets and Liabilities Associated with Contracts from Customers (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Disaggregation Of Revenue [Line Items]
Accounts receivable	$ 60,452	$ 43,129
Short-term deferred revenue	97,333	80,782
Long-term deferred revenue	47,529	$ 41,785
Other Current Assets [Member]
Disaggregation Of Revenue [Line Items]
Short-term unbilled receivables	$ 1,362

REVENUE RECOGNITION - Summary o

REVENUE RECOGNITION - Summary of Significant Changes in Unbilled Receivables and Deferred Liabilities Balances (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Deferred Revenue (Increase) Decrease
Balance at December 31, 2018	$ (122,567)	$ (38,883)
Adoption of Topic 606 on January 1, 2018		(21,307)
Adjusted balance on January 1, 2018		(60,190)
Revenue recognized that was previously included in deferred revenue	133,394	64,562
Increases due to cash received	(157,321)	(130,639)
Cumulative catch-up adjustment arising from changes in estimates of transaction price	1,632	3,700
Net change	(22,295)	(62,377)
Balance at December 31, 2019	(144,862)	(122,567)
Unbilled Receivables Increase (Decrease)
Balance at December 31, 2018	1,020	70
Adoption of Topic 606 on January 1, 2018		307
Adjusted balance on January 1, 2018		377
Unbilled receivables recognized	1,834	2,024
Transferred to receivables from unbilled receivables	(1,492)	(1,381)
Net change	342	643
Balance at December 31, 2019	$ 1,362	$ 1,020

REVENUE RECOGNITION - Summary_2

REVENUE RECOGNITION - Summary of Impacts of Adopting Topic 606 on Consolidated Financial Statements (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2015
ASSETS
Other assets (current and non-current)					$ 70,892					$ 70,892
Deferred income taxes	$ 30,375				24,377				$ 30,375	24,377
TOTAL ASSETS	1,120,157				933,424				1,120,157	933,424
LIABILITIES AND SHAREHOLDERS’ EQUITY
Deferred revenue (current and non-current)	144,862				122,567				144,862	122,567	$ 38,883
Retained earnings	249,003				129,552				249,003	129,552
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	1,120,157				933,424				1,120,157	933,424
REVENUE	101,729	$ 97,515	$ 118,168	$ 87,765	70,143	$ 77,550	$ 56,149	$ 43,572	405,177	247,414	335,629
Gross margin									329,803	193,873	280,931
OPERATING INCOME									158,343	56,735	146,247
INCOME BEFORE INCOME TAXES									169,905	64,311	149,537
INCOME TAX EXPENSE									(31,601)	(5,471)	(45,652)
NET INCOME	$ 26,428	$ 36,962	$ 43,440	$ 31,474	19,249	$ 22,818	$ 10,814	$ 5,959	138,304	58,840	103,885	$ 103,885
CASH FLOWS FROM OPERATING ACTIVITIES:
Amortization of deferred revenue and recognition of unbilled receivables									(135,368)	(68,905)	(11,122)
Deferred income tax (benefit) expense									(5,776)	(12,814)	24,396
Other assets (current and non-current)										(59,062)
Net cash provided by operating activities									$ 193,912	121,796	$ 133,365
Revenue from Contracts with Customers - ASU No. 2014-09 [Member]
LIABILITIES AND SHAREHOLDERS’ EQUITY
REVENUE										78,900
Adjustment [Member] | Revenue from Contracts with Customers - ASU No. 2014-09 [Member]
ASSETS
Deferred income taxes					(11,153)					(11,153)
TOTAL ASSETS					(11,153)					(11,153)
LIABILITIES AND SHAREHOLDERS’ EQUITY
Deferred revenue (current and non-current)					(99,885)					(99,885)
Retained earnings					88,732					88,732
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY					(11,153)					(11,153)
REVENUE										78,885
Gross margin										78,885
OPERATING INCOME										78,885
INCOME BEFORE INCOME TAXES										78,885
INCOME TAX EXPENSE										(7,252)
NET INCOME										71,633
CASH FLOWS FROM OPERATING ACTIVITIES:
Amortization of deferred revenue and recognition of unbilled receivables										(81,991)
Deferred income tax (benefit) expense										10,358
Balances Without Adoption of Topic 606 [Member] | Revenue from Contracts with Customers - ASU No. 2014-09 [Member]
ASSETS
Other assets (current and non-current)					70,892					70,892
Deferred income taxes					13,224					13,224
TOTAL ASSETS					922,271					922,271
LIABILITIES AND SHAREHOLDERS’ EQUITY
Deferred revenue (current and non-current)					22,682					22,682
Retained earnings					218,284					218,284
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY					$ 922,271					922,271
REVENUE										326,299
Gross margin										272,758
OPERATING INCOME										135,620
INCOME BEFORE INCOME TAXES										143,196
INCOME TAX EXPENSE										(12,723)
NET INCOME										130,473
CASH FLOWS FROM OPERATING ACTIVITIES:
Amortization of deferred revenue and recognition of unbilled receivables										(150,896)
Deferred income tax (benefit) expense										(2,456)
Other assets (current and non-current)										(59,062)
Net cash provided by operating activities										$ 121,796

NET INCOME PER COMMON SHARE - S

NET INCOME PER COMMON SHARE - Schedule of Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2015
Numerator:
Net income	$ 26,428	$ 36,962	$ 43,440	$ 31,474	$ 19,249	$ 22,818	$ 10,814	$ 5,959	$ 138,304	$ 58,840	$ 103,885	$ 103,885
Adjustment for Basic EPS:
Earnings allocated to unvested shareholders									(1,106)	(690)		(1,638)
Adjusted net income									$ 137,198	$ 58,150		$ 102,247
Denominator:
Weighted average common shares outstanding – Basic									46,959,775	46,849,588	46,725,289	46,725,289
Effect of dilutive shares:
Common stock equivalents arising from stock options and ESPP									1,334	1,956		2,611
Restricted stock awards and units and performance units									34,353	45,222		77,294
Weighted average common shares outstanding – Diluted									46,995,462	46,896,766	46,805,194	46,805,194
Basic	$ 0.56	$ 0.78	$ 0.92	$ 0.66	$ 0.40	$ 0.48	$ 0.23	$ 0.13	$ 2.92	$ 1.24	$ 2.19	$ 2.19
Diluted	$ 0.56	$ 0.78	$ 0.92	$ 0.66	$ 0.40	$ 0.48	$ 0.23	$ 0.13	$ 2.92	$ 1.24	$ 2.18	$ 2.18

NET INCOME PER COMMON SHARE - A

NET INCOME PER COMMON SHARE - Additional Information (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share [Abstract]
Antidilutive securities excluded from calculation of diluted EPS	0	4,414	0

QUARTERLY SUPPLEMENTAL FINANC_3

QUARTERLY SUPPLEMENTAL FINANCIAL DATA (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 101,729	$ 97,515	$ 118,168	$ 87,765	$ 70,143	$ 77,550	$ 56,149	$ 43,572	$ 405,177	$ 247,414	$ 335,629
Net income	$ 26,428	$ 36,962	$ 43,440	$ 31,474	$ 19,249	$ 22,818	$ 10,814	$ 5,959	$ 138,304	$ 58,840	$ 103,885	$ 103,885
Net income per common share:
Basic	$ 0.56	$ 0.78	$ 0.92	$ 0.66	$ 0.40	$ 0.48	$ 0.23	$ 0.13	$ 2.92	$ 1.24	$ 2.19	$ 2.19
Diluted	$ 0.56	$ 0.78	$ 0.92	$ 0.66	$ 0.40	$ 0.48	$ 0.23	$ 0.13	$ 2.92	$ 1.24	$ 2.18	$ 2.18