Exact Sciences (EXAS) 10-K 16 Feb 21 2020 FY Annual report Financial data

Cover Page

Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 15, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Transition Report	false
Entity File Number	001-35092
Entity Registrant Name	EXACT SCIENCES CORPORATION
Entity Central Index Key	0001124140
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	5505 Endeavor Lane
Entity Address, City or Town	Madison
Entity Address, State or Province	WI
Entity Tax Identification Number	02-0478229
Entity Address, Postal Zip Code	53719
City Area Code	608
Local Phone Number	284‑5700
Title of 12(b) Security	Common Stock, $0.01 Par Value
Trading Symbol	EXAS
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Amendment Flag	false
Entity Filer Category	Large Accelerated Filer
Current Fiscal Year End Date	--12-31
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 12,901,152,054
Entity Common Stock, Shares Outstanding		169,093,162
Documents Incorporated by Reference	The registrant intends to file a definitive proxy statement pursuant to Regulation 14A within 120 days after the end of the fiscal year ended December 31, 2020. Portions of such proxy statement are incorporated by reference into Part III of this Form 10‑K.
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current Assets:
Cash and cash equivalents	$ 1,491,288	$ 177,254
Marketable securities	348,699	146,401
Accounts receivable, net	233,185	130,362
Inventory	92,265	61,724
Prepaid expenses and other current assets	33,157	38,195
Total current assets	2,198,594	553,936
Long-term Assets:
Property, plant and equipment, net	450,683	455,325
Operating lease right-of-use assets	125,947	126,444
Goodwill	1,237,672	1,203,197
Intangible assets, net	848,426	1,143,550
Other long-term assets, net	63,770	23,316
Total assets	4,925,092	3,505,768
Current Liabilities:
Accounts payable	35,709	25,973
Accrued liabilities	233,604	193,329
Operating lease liabilities, current portion	11,483	7,891
Convertible notes, net, current portion	255,464	0
Debt, current portion	1,319	834
Other current liabilities	38,265	8,467
Total current liabilities	575,844	236,494
Convertible notes, net, less current portion	1,320,760	803,605
Long-term debt, less current portion	22,342	24,032
Other long-term liabilities	61,582	34,911
Operating lease liabilities, less current portion	121,075	118,665
Total liabilities	2,101,603	1,217,707
Commitments and contingencies
Stockholders’ Equity:
Preferred stock, $0.01 par value Authorized—5,000,000 shares issued and outstanding—no shares at December 31, 2020 and December 31, 2019	0	0
Common stock, $0.01 par value Authorized—400,000,000 shares issued and outstanding—159,423,410 and 147,625,696 shares at December 31, 2020 and December 31, 2019	1,595	1,477
Additional paid-in capital	4,789,657	3,406,440
Accumulated other comprehensive income (loss)	526	(100)
Accumulated deficit	(1,968,289)	(1,119,756)
Total stockholders’ equity	2,823,489	2,288,061
Total liabilities and stockholders’ equity	$ 4,925,092	$ 3,505,768

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Revenue	$ 1,491,391	$ 876,293	$ 454,462
Operating expenses:
Cost of sales (exclusive of amortization of acquired intangible assets)	354,324	216,717	116,644
Research and development	554,052	139,694	67,285
Sales and marketing	589,919	385,176	249,448
General and administrative	481,716	352,453	178,016
Amortization of acquired intangibles	93,398	16,035	2,540
Intangible asset impairment charge	209,666	0	0
Total operating expenses	2,283,075	1,110,075	613,933
Other operating income	23,665	0	0
Loss from operations	(768,019)	(233,782)	(159,471)
Other income (expense)
Investment income, net	6,897	26,530	21,203
Interest expense	(95,983)	(61,599)	(36,789)
Total other income (expense)	(89,086)	(35,069)	(15,586)
Net loss before tax	(857,105)	(268,851)	(175,057)
Income tax benefit (expense)	8,572	184,858	(92)
Net loss	$ (848,533)	$ (83,993)	$ (175,149)
Net loss per share-basic and diluted (in dollars per share)	$ (5.61)	$ (0.64)	$ (1.43)
Weighted average common shares outstanding-basic and diluted (in shares)	151,137	131,257	122,207

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net loss	$ (848,533)	$ (83,993)	$ (175,149)
Other comprehensive loss:
Unrealized gain (loss) on available-for-sale investments	771	1,322	(708)
Foreign currency adjustment	25	0	36
Comprehensive loss, before tax	(847,737)	(82,671)	(175,821)
Income tax expense related to items of other comprehensive income	(170)	0	0
Comprehensive loss, net of tax	$ (847,907)	$ (82,671)	$ (175,821)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders’ Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance at Dec. 31, 2017	$ 520,418	$ 1,205	$ 1,380,577	$ (750)	$ (860,614)
Beginning balance (in shares) at Dec. 31, 2017		120,497,426
Increase (Decrease) in Stockholders' Equity
Equity component of convertible debt, net of issuance costs	260,246		260,246
Settlement of convertible notes, net of tax	0
Exercise of common stock options	6,636	$ 10	6,626
Exercise of common stock options (in shares)		1,033,012
Issuance of common stock to fund the Company's 401(k) match	4,303	$ 1	4,302
Issuance of common stock to fund the Company's 401(k) match (in shares)		86,882
Compensation expense related to issuance of stock options and restricted stock awards	60,264	$ 13	60,251
Compensation expense related to issuance of stock options and restricted stock awards (in shares)		1,228,611
Purchase of employee stock purchase plan shares	4,895	$ 3	4,892
Purchase of employee stock purchase plan shares (in shares)		346,609
Issuance of common stock for business combinations	0
Net loss	(175,149)				(175,149)
Accumulated other comprehensive income (loss)	(672)			(672)
Ending balance at Dec. 31, 2018	680,941	$ 1,232	1,716,894	(1,422)	(1,035,763)
Ending balance (in shares) at Dec. 31, 2018		123,192,540
Increase (Decrease) in Stockholders' Equity
Equity component of convertible debt, net of issuance costs	268,368		268,368
Settlement of convertible notes, net of tax	(300,768)		(300,768)
Shares issued to settle convertible notes	$ 182,477	$ 22	182,455
Shares issued to settle convertible notes (in shares)	2,159,716	2,159,716
Exercise of common stock options	$ 8,787	$ 6	8,781
Exercise of common stock options (in shares)		641,925
Issuance of common stock to fund the Company's 401(k) match	7,409	$ 1	7,408
Issuance of common stock to fund the Company's 401(k) match (in shares)		86,532
Compensation expense related to issuance of stock options and restricted stock awards	108,483	$ 43	108,440
Compensation expense related to issuance of stock options and restricted stock awards (in shares)		4,322,366
Purchase of employee stock purchase plan shares	8,396	$ 2	8,394
Purchase of employee stock purchase plan shares (in shares)		176,458
Issuance of common stock for business combinations	$ 1,407,080	$ 171	1,406,909
Issuance of common stock to fund business combinations (in shares)	17,046,159	17,046,159
Stock issuance costs	$ (441)		(441)
Net loss	(83,993)				(83,993)
Accumulated other comprehensive income (loss)	1,322			1,322
Ending balance at Dec. 31, 2019	$ 2,288,061	$ 1,477	3,406,440	(100)	(1,119,756)
Ending balance (in shares) at Dec. 31, 2019	147,625,696	147,625,696
Increase (Decrease) in Stockholders' Equity
Equity component of convertible debt, net of issuance costs	$ 346,641		346,641
Settlement of convertible notes, net of tax	(64,199)		(64,199)
Exercise of common stock options	$ 27,077	$ 7	27,070
Exercise of common stock options (in shares)	707,013	702,907
Issuance of common stock to fund the Company's 401(k) match	$ 12,007	$ 1	12,006
Issuance of common stock to fund the Company's 401(k) match (in shares)		136,559
Compensation expense related to issuance of stock options and restricted stock awards	152,906	$ 17	152,889
Compensation expense related to issuance of stock options and restricted stock awards (in shares)		1,665,408
Purchase of employee stock purchase plan shares	18,355	$ 3	18,352
Purchase of employee stock purchase plan shares (in shares)		301,064
Issuance of common stock for business combinations	$ 28,847	$ 4	28,843
Issuance of common stock to fund business combinations (in shares)	386,293	386,293
Issuance of common stock for registered direct offering	$ 861,701	$ 86	861,615
Issuance of common stock, net of issuance costs (in shares)		8,605,483
Net loss	(848,533)				(848,533)
Accumulated other comprehensive income (loss)	626			626
Ending balance at Dec. 31, 2020	$ 2,823,489	$ 1,595	$ 4,789,657	$ 526	$ (1,968,289)
Ending balance (in shares) at Dec. 31, 2020	159,423,410	159,423,410

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net loss	$ (848,533)	$ (83,993)	$ (175,149)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and other amortization	69,964	34,212	20,544
Loss on disposal of property, plant and equipment	2,470	1,394	353
Unrealized net (gain) loss on revaluation of equity securities	(1,179)	207	0
Loss on preferred stock investment	0	0	765
Deferred tax benefit	(9,862)	(185,109)	0
Stock-based compensation	152,906	108,483	60,264
Loss on settlement of convertible notes	7,954	10,558	0
Amortization of convertible note debt discount and issuance costs	76,479	42,256	28,564
Amortization of deferred financing costs and other liabilities	(3,889)	(4,467)	(2,394)
Accretion (Amortization) of discount (premium) on short-term investments	1,549	(3,102)	(3,516)
Amortization of acquired intangibles	93,398	16,035	2,540
Asset acquisition IPR&D expense	412,568	0	0
Intangible asset impairment charge	209,666	0	0
Non-cash lease expense	15,720	5,427	0
Changes in assets and liabilities, net of effects of acquisition:
Accounts receivable, net	(100,526)	(27,633)	(17,292)
Inventory, net	(30,310)	(19,041)	(12,729)
Operating lease liabilities	(8,784)	(4,114)	0
Accounts payable and accrued liabilities	55,165	3,469	33,076
Other assets and liabilities	41,726	(6,237)	(3,966)
Net cash provided by (used in) operating activities	136,482	(111,655)	(68,940)
Cash flows from investing activities:
Purchases of marketable securities	(1,089,953)	(634,117)	(1,192,506)
Maturities of marketable securities	886,675	1,657,204	578,786
Purchases of property, plant and equipment	(64,352)	(171,802)	(150,093)
Investment in privately held companies	(15,947)	(1,000)	0
Business combination, net of cash acquired	(6,658)	(973,861)	(17,908)
Asset acquisition, net of cash acquired	(411,421)	0	0
Other investing activities	(381)	(852)	(578)
Net cash used in investing activities	(702,037)	(124,428)	(782,299)
Cash flows from financing activities:
Proceeds from issuance of convertible notes, net	1,125,547	729,477	896,430
Proceeds from exercise of common stock options	27,077	8,787	6,636
Proceeds from sale of common stock, net of issuance costs	861,701	0	0
Proceeds in connection with the Company's employee stock purchase plan	18,355	8,396	4,895
Payments on settlement of convertible notes	(150,054)	(493,356)	0
Proceeds from construction loan, net deferred financing costs	0	319	24,236
Other financing activities	(3,005)	(442)	1,945
Net cash provided by financing activities	1,879,621	253,181	934,142
Effects of exchange rate changes on cash and cash equivalents	0	0	36
Net increase in cash, cash equivalents and restricted cash	1,314,066	17,098	82,939
Cash, cash equivalents and restricted cash at the beginning of period	177,528	160,430	77,491
Cash, cash equivalents and restricted cash at the end of period	1,491,594	177,528	160,430
Supplemental disclosure of non-cash investing and financing activities:
Property, plant and equipment acquired but not paid	2,685	10,265	33,452
Property acquired under build-to-suit lease	0	0	2,092
Unrealized loss on available-for-sale investments	771	1,322	(708)
Issuance of 136,559, 86,532, and 86,882 shares of common stock to fund the Company’s 401(k) matching contribution for 2019, 2018, and 2017, respectively	12,007	7,409	4,303
Issuance of 2,159,716 shares of common stock upon settlement of convertible notes	0	182,477	0
Retirement of equity component of convertible notes settled	(64,199)	(300,768)	0
Issuance of 386,293 and 17,046,159 shares of common stock in 2020 and 2019, respectively, for business combination	(28,847)	(1,407,080)	0
Business acquisition contingent consideration liability	0	0	3,060
Supplemental disclosure of cash flow information:
Interest paid	$ 9,384	$ 5,128	$ 4,638

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized shares (in shares)	5,000,000	5,000,000
Preferred stock, issued shares (in shares)	0	0
Preferred stock, outstanding shares (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized shares (in shares)	400,000,000	400,000,000
Common stock, issued shares (in shares)	159,423,410	147,625,696
Common stock, outstanding shares (in shares)	159,423,410	147,625,696

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows (Parenthetical) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Cash Flows [Abstract]
Issuance of shares of common stock to fund the Company's 401(k) matching contribution (in shares)	136,559	86,532	86,882
Shares issued to settle convertible notes (in shares)		2,159,716
Issuance of common stock to fund business combinations (in shares)	386,293	17,046,159

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Business Exact Sciences Corporation (together with its subsidiaries, “Exact,” or the “Company”) was incorporated in February 1995. Exact is a leading global cancer screening and diagnostics company. It has developed some of the most impactful brands in cancer screening and diagnostics, including Cologuard ® and Oncotype DX ® . Exact is currently working on the development of additional tests, with the goal of bringing new innovative cancer tests to patients throughout the world. Basis of Presentation and Principles of Consolidation The accompanying consolidated financial statements include the accounts of Exact Sciences Corporation and those of its wholly-owned subsidiaries and variable interest entities. All intercompany transactions and balances have been eliminated upon consolidation. Use of Estimates The preparation of the consolidated financial statements in conformity with accounting principles generally accepted in the United States ("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. Critical accounting policies are those that affect the Company's financial statements materially and involve difficult, subjective or complex judgments by management, and actual results could differ from those estimates. These estimates include revenue recognition, valuation of convertible notes, valuation of intangible assets and goodwill, and accounting for income taxes among others. The spread of the coronavirus (“COVID-19”) has affected many segments of the global economy, including the cancer screening and diagnostics industry. The COVID-19 outbreak, which the World Health Organization has classified as a pandemic, has prompted governments and regulatory bodies throughout the world to enact broad precautionary measures, including “stay-at-home” orders, restrictions on the performance of “non-essential” services, public gatherings and travel. Health systems, including key markets where the Company operates, have been, or may be, overwhelmed with high volumes of patients suffering from COVID-19. Even in areas where “stay-at-home” restrictions have been lifted and the number of cases of COVID-19 has declined, many individuals remain cautious about resuming activities such as preventive-care medical visits. Medical practices continue to be cautious about allowing individuals, such as sales representatives, into their offices. Many individuals continue to work from home rather from an office setting. The Company cannot forecast when the COVID-19 pandemic will end or the extent to which practices that have emerged during the pandemic will continue once it subsides. The extent to which COVID-19 impacts the Company’s business and financial results will depend on numerous evolving factors including, but not limited to: the magnitude and duration of COVID-19, the extent to which it will impact worldwide macroeconomic conditions including interest rates, employment rates and health insurance coverage, the speed of the anticipated recovery, access to capital markets, and governmental and business reactions to the pandemic. The Company assessed certain accounting matters that generally require consideration of forecasted financial information in context with the information reasonably available to the Company and the unknown future impacts of COVID-19 as of December 31, 2020 and through the date of the filing of this Annual Report on Form 10-K. The accounting matters assessed included, but were not limited to, the Company’s allowance for doubtful accounts and credit losses, equity investments, software, and the carrying value of the goodwill and other long-lived assets. The Company’s future assessment of the magnitude and duration of COVID-19, as well as other factors, could result in additional material impacts to the Company’s consolidated financial statements in future reporting periods. The pandemic and related precautionary measures began to materially disrupt the Company's operations in March 2020 and may continue to disrupt the business for an unknown period of time. As a result, the pandemic had a significant impact on the Company's 2020 revenues and operating results. The ultimate impact of COVID-19 depends on factors beyond the Company’s knowledge or control, including the duration and severity of the outbreak, as well as third-party actions taken to contain its spread and mitigate its public health effects. As a result, the Company is unable to estimate the extent to which COVID-19 will negatively impact its financial results or liquidity. Coronavirus Aid, Relief, and Economic Security Act (“CARES Act”) In April 2020, the Company received $23.7 million from the United States Department of Health and Human Services (“HHS”) as a distribution from the Public Health and Social Services Emergency Fund provided for in the CARES Act. The fund payments are grants, not loans, and HHS will not require repayment provided the funds are utilized to offset expenses incurred to address COVID-19 or to replace lost revenues. The Company accepted the terms and conditions of the grant in May 2020 and recognized the entire $23.7 million during the year ended December 31, 2020, due to lost revenue attributable to COVID-19, which is reflected in other operating income in the consolidated statement of operations. The Company cannot predict the extent to which it might receive any additional funds to be paid out under the Provider Relief Fund, and to what extent the financial impact of receiving such funds might offset the broad implications of the COVID-19 pandemic, which include increases in the Company’s costs and lost revenues. Cash and Cash Equivalents The Company considers cash on hand, demand deposits in a bank, money market funds, and all highly liquid investments with an original maturity of 90 days or less to be cash and cash equivalents. Marketable Securities Management determines the appropriate classification of debt securities at the time of purchase and re-evaluates such designation as of each balance sheet date. Debt securities carried at amortized cost are classified as held-to-maturity when the Company has the positive intent and ability to hold the securities to maturity. Debt securities not classified as held-to-maturity are classified as available-for-sale. Available-for-sale securities are carried at fair value. The unrealized gains and losses, net of tax, on the Company's debt securities are reported in other comprehensive income. Marketable equity securities are measured at fair value and the unrealized gains and losses, net of tax, are recognized in other income (expense) in the consolidated statements of operations. The amortized cost of debt securities in this category is adjusted for amortization of premiums and accretion of discounts to maturity computed under the effective interest rate method. Such amortization is included in investment income, net. Realized gains and losses and declines in value as a result of credit losses on available-for-sale securities are included in the consolidated statements of operations as investment income, net. The cost of securities sold is based on the specific identification method. Interest and dividends on securities classified as available-for-sale are included in the consolidated statements of operations as investment income, net. The Company’s investment policy limits investments to certain types of instruments issued by institutions with investment grade credit ratings and places restrictions on maturities and concentration by type and issuer. Investments in which the Company has the ability and intent, if necessary, to liquidate in order to support its current operations (including those with a contractual term greater than one year from the date of purchase) are classified as current. The Company periodically evaluates its available-for-sale debt securities in unrealized loss positions to determine whether any impairment is a result of a credit loss or other factors. This evaluation includes, but is not limited to, significant quantitative and qualitative assessments and estimates regarding credit ratings, significance of a security’s loss position, adverse conditions specifically related to the security, and the payment structure of the security. Allowance for Doubtful Accounts The Company estimates an allowance for doubtful accounts against accounts receivable using historical collection trends, aging of accounts, current and future implications surrounding the ability to collect such as economic conditions, and regulatory changes. The allowance for doubtful accounts is evaluated on a regular basis and adjusted when trends, significant events or other substantive evidence indicate that expected collections will be less than applicable accrual rates. At December 31, 2020 and 2019, the allowance for doubtful accounts recorded was not material to the Company's consolidated balance sheets. For the years ended December 31, 2020, 2019 and 2018, there was an immaterial amount of bad debt expense written off against the allowance and charged to operating expense. Inventory Inventory is stated at the lower of cost or net realizable value. The Company determines the cost of inventory using the first-in, first out method (“FIFO”). The Company estimates the recoverability of inventory by reference to internal estimates of future demands and product life cycles, including expiration. The Company periodically analyzes its inventory levels to identify inventory that may expire prior to expected sale, no longer meet quality specifications, or has a cost basis in excess of its estimated realizable value and records a charge to cost of sales for such inventory as appropriate. Direct and indirect manufacturing costs incurred during process validation with probable future economic benefit are capitalized. Validation costs incurred for other research and development activities, which are not permitted to be sold, have been expensed to research and development in the Company’s consolidated statements of operations. Property, Plant and Equipment Property, plant and equipment are stated at cost and depreciated using the straight-line method over the assets’ estimated useful lives. Land is stated at cost and does not depreciate. Additions and improvements are capitalized, including direct and indirect costs incurred to validate equipment and bring to working conditions. Revalidation costs, including maintenance and repairs are expensed when incurred. Software Development Costs Costs related to internal use software, including hosted arrangements, are incurred in three stages: the preliminary project stage, the application development stage, and the post-implementation stage. Costs incurred during the preliminary project and post-implementation stages are expensed as incurred. Costs incurred during the application development stage that meet the criteria for capitalization are capitalized and amortized, when the software is ready for its intended use, using the straight‑line basis over the estimated useful life of the software, or the duration of the hosting agreement. Investments in Privately Held Companies The Company determines whether its investments in privately held companies are debt or equity based on their characteristics, in accordance with the applicable accounting guidance for such investments. The Company also evaluates the investee to determine if the entity is a variable interest entity (“VIE”) and, if so, whether the Company is the primary beneficiary of the VIE, in order to determine whether consolidation of the VIE is required. If consolidation is not required and the Company does not have voting control of the entity, the investment is evaluated to determine if the equity method of accounting should be applied. The equity method applies to investments in common stock or in substance common stock where the Company exercises significant influence over the investee. Investments in privately held companies determined to be equity securities are accounted for as non-marketable securities. The Company adjusts the carrying value of its non-marketable equity securities for changes from observable transactions for identical or similar investments of the same issuer, less impairment. All gains and losses on non-marketable equity securities, realized and unrealized, are recognized in investment income, net in the consolidated statements of operations. Investments in privately held companies determined to be debt securities are accounted for as available-for-sale or held to maturity securities, in accordance with the applicable accounting guidance for such investments. Derivative Financial Instruments The Company hedges a portion of its foreign currency exposures related to outstanding monetary assets and liabilities using foreign currency forward contracts. The foreign currency forward contracts are included in prepaid expenses and other current assets or in accrued liabilities in the consolidated balance sheets, depending on the contracts’ net position. These contracts are not designated as hedges, and as a result, changes in their fair value are recorded in other income (expense) in the consolidated statements of operations. Business Combinations and Asset Acquisitions Business Combinations are accounted for under the acquisition method in accordance with Accounting Standards Codification ("ASC") 805, Business Combinations. The acquisition method requires identifiable assets acquired and liabilities assumed and any non-controlling interest in the business acquired be recognized and measured at fair value on the acquisition date, which is the date that the acquirer obtains control of the acquired business. The amount by which the fair value of consideration transferred as the purchase price exceeds the net fair value of assets acquired and liabilities assumed is recorded as goodwill. Acquisitions that do not meet the definition of a business combination under the ASC are accounted for as asset acquisitions. Asset acquisitions are accounted for by allocating the cost of the acquisition to the individual assets acquired and liabilities assumed on a relative fair value basis. Goodwill is not recognized in an asset acquisition with any consideration in excess of net assets acquired allocated to acquired assets on a relative fair value basis. Transaction costs are expensed in a business combination and are considered a component of the cost of the acquisition in an asset acquisition. Intangible Assets Purchased intangible assets are recorded at fair value. The Company uses a discounted cash flow model to value intangible assets. The discounted cash flow model requires assumptions about the timing and amount of future net cash flows, risk, the cost of capital, terminal values and market participants. Patent costs are capitalized as incurred, only if the Company determines that there is some probable future economic benefit derived from the transaction. A capitalized patent is amortized over its estimated useful life, beginning when such patent is approved. Capitalized patent costs are expensed upon disapproval, upon a decision by the Company to no longer pursue the patent or when the related intellectual property is either sold or deemed to be no longer of value to the Company. The Company determined that all patent costs incurred during the years ended December 31, 2020, 2019 and 2018 should be expensed and not capitalized as the future economic benefit derived from the patent costs incurred cannot be determined. Acquired In-process Research and Development ("IPR&D") Acquired IPR&D represents the fair value assigned to research and development assets that have not reached technological feasibility. The value assigned to acquired IPR&D is determined by estimating the costs to develop the acquired technology into commercially viable products, estimating the resulting revenues from the projects and discounting the net cash flows to present value. The revenues and cost projections used to value acquired IPR&D are, as applicable, reduced based on the probability of success. IPR&D projects acquired in a business combination that are not complete are capitalized and accounted for as indefinite-lived intangible assets until completion or abandonment of the related R&D efforts. Upon successful completion of the project, the capitalized amount is amortized over its estimated useful life. If a project is abandoned, all remaining capitalized amounts are written off immediately. There are often major risks and uncertainties associated with IPR&D projects as we are required to obtain regulatory approvals in order to be able to market the resulting products. Such approvals require completing clinical trials that demonstrate the products effectiveness. Consequently, the eventual realized value of the IPR&D project may vary from its fair value at the date of acquisition, and IPR&D impairment charges may occur in future periods. Capitalized IPR&D projects are tested for impairment annually and whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. The Company considers various factors for potential impairment, including the current legal and regulatory environment, current and future strategic initiatives and the competitive landscape. Adverse clinical trial results, significant delays in obtaining marketing approval, the inability to bring a product to market and the introduction or advancement of competitors' products could result in partial or full impairment of the related intangible assets. Goodwill The Company evaluates goodwill for possible impairment in accordance with Financial Accounting Standards Board ("FASB") ASC 350 on an annual basis during the fourth quarter, or more frequently if events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. Qualitative factors considered in this assessment include industry and market conditions, overall financial performance, and other relevant events and factors affecting the Company's business. Based on the qualitative assessment, if it is determined that the fair value of goodwill is more likely than not to be less than its carrying amount, the fair value of a reporting unit will be calculated and compared with its carrying amount and an impairment charge will be recognized for the amount that the carrying value exceeds the fair value. Impairment of Long-Lived Assets The Company evaluates the fair value of long-lived assets, which include property, plant and equipment, finite-lived intangible assets, and investments in privately held companies, for impairment whenever events or changes in circumstances indicate that the carrying amounts of the assets may not be fully recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to future undiscounted net cash flows expected to be generated by the asset. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds the fair value of the assets. Assets to be disposed of are reported at the lower of the carrying amount or fair value less costs to sell. Net Loss Per Share Basic net loss per common share was determined by dividing net loss applicable to common stockholders by the weighted average common shares outstanding during the period. Basic and diluted net loss per share is the same because all outstanding common stock equivalents have been excluded, as they are anti-dilutive as a result of the Company’s losses. The following potentially issuable common shares were not included in the computation of diluted net loss per share because they would have an anti-dilutive effect due to net losses for each period: December 31, (In thousands) 2020 2019 2018 Shares issuable in connection with acquisitions 157 — — Shares issuable upon exercise of stock options 2,231 2,700 2,532 Shares issuable upon the release of restricted stock awards 3,968 3,801 3,847 Shares issuable upon the release of performance share units 619 583 2,399 Shares issuable upon conversion of convertible notes 20,309 12,196 12,044 27,284 19,280 20,822 Accounting for Stock-Based Compensation The Company requires all share-based payments to employees, including grants of employee stock options, restricted stock, restricted stock units, shares purchased under an employee stock purchase plan (if certain parameters are not met), and performance share units to be recognized in the financial statements based on their grant date fair values. Forfeitures of any share-based awards are recognized as they occur. The fair values and recognition of the Company's share-based payment awards are determined as follows: The fair value of each service-based option award is estimated on the date of grant using the Black-Scholes option-pricing model. The Black-Scholes pricing model utilizes the following assumptions: Expected Term —Expected life of an option award is the average length of time over which the Company expects employees will exercise their options, which is based on historical experience with similar grants. Expected Volatility —Expected volatility is based on the Company’s historical stock volatility data over the expected term of the awards. Risk-Free Interest Rate —The Company bases the risk-free interest rate on the implied yield currently available on U.S. Treasury zero-coupon issues with an equivalent expected term. The estimated fair value of these awards is recognized to expense using the straight-line method over the expected term. The fair value of service-based awards for each restricted stock unit award is determined on the date of grant using the closing stock price on that day. The estimated fair value of these awards is recognized to expense using the straight-line method over the vesting period. Research and Development Costs Research and development costs are expensed as incurred. These expenses include the costs of our proprietary research and development efforts, as well as costs of IPR&D projects acquired as part of an asset acquisition that have no alternative future use. Upfront and milestone payments due to third parties in connection with research and development collaborations prior to regulatory approval are expensed as incurred. Milestone payments due to third parties upon, or subsequent to, regulatory approval are capitalized and amortized into research and development costs over the shorter of the remaining license or product patent life, when there are no corresponding revenues related to the license or product. Nonrefundable advance payments for goods and services that will be used in future research and development activities are expensed when the activity has been performed or when the goods have been received, rather than when the payment is made. The Company incurred research and development expenses of $554.1 million, $139.7 million, and $67.3 million during the years ended December 31, 2020, 2019, and 2018, respectively, including IPR&D of $412.6 million that was acquired in an asset acquisition in 2020 and had no alternative future use. The value of the acquired IPR&D that was expensed was determined by identifying those acquired specific IPR&D projects that would be continued and which (a) were incomplete and (b) had no alternative future use. Acquired IPR&D assets that are acquired in an asset acquisition and which have no alternative future use are classified as an investing cash outflow in the consolidated statement of cash flows. Advertising Costs The Company expenses the costs of media advertising at the time the advertising takes place. The Company expensed approximately $93.2 million, $88.7 million, and $93.7 million of media advertising during the years ended December 31, 2020, 2019, and 2018, respectively, which is recorded in sales and marketing expenses on the Company's consolidated statements of operations. Fair Value Measurements The FASB has issued authoritative guidance that requires fair value to be based on the assumptions market participants would use when pricing an asset or liability and establishes a fair value hierarchy that prioritizes the information used to develop those assumptions. Under that standard, fair value measurements are separately disclosed by level within the fair value hierarchy. The fair value hierarchy establishes and prioritizes the inputs used to measure fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs. Observable inputs are inputs that reflect the assumptions that market participants would use in pricing the asset or liability developed based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the assumptions market participants would use in pricing the asset or liability developed based on the best information available in the circumstances. Convertible Notes The Company accounts for convertible debt instruments that may be settled in cash or equity upon conversion by separating the liability and equity components of the instruments in a manner that reflects the Company’s nonconvertible debt borrowing rate. The Company determines the carrying amount of the liability component of the convertible debt instrument by using assumptions that market participants would use in pricing a debt instrument, including market interest rates, credit standing, yield curves, volatilities, and expected life of the instrument. Determining the fair value of the debt component requires the use of accounting estimates and assumptions. These estimates and assumptions are judgmental in nature and could have a significant impact on the determination of the debt component, and the associated non-cash interest expense. The amount allocated to the equity component is the difference between the principal value of the instrument and the fair value of the liability component at issuance. The equity component, less any premium, is treated as a discount on the liability component. The debt discount is amortized to interest expense over the contractual term of the debt instrument using the effective interest rate method. In addition, debt issuance costs related to the debt instrument are allocated to the liability and equity components based on their relative values. The debt issuance costs allocated to the liability component are amortized over the contractual term of the debt instrument as additional non-cash interest expense. The transaction costs allocated to the equity component are netted with the equity component of the convertible debt instrument in stockholders equity. Leases The Company acts as lessee in its lease agreements, which include operating leases for corporate offices, laboratory space, warehouse space, vehicles and certain laboratory and office equipment, and finance leases for certain equipment and vehicles. The Company determines whether an arrangement is, or contains, a lease at inception. At the beginning of fiscal year 2019, the company adopted ASC Topic 842. The Company records the present value of lease payments as right-of-use (“ROU”) assets and lease liabilities on the consolidated balance sheets. ROU assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent an obligation to make lease payments based on the present value of lease payments over the lease term. Classification of lease liabilities as either current or non-current is based on the expected timing of payments due under the Company’s obligations. As most of the Company’s leases do not provide an implicit interest rate, the Company uses its incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. The incremental borrowing rate is the rate of interest that a lessee would have to pay to borrow on a collateralized basis over a similar term and at an amount equal to the lease payments in a similar economic environment. In order to determine the appropriate incremental borrowing rates, the Company has used a number of factors including the credit rating, and the lease term. The ROU asset also consists of any lease incentives received. The lease terms used to calculate the ROU asset and related lease liability include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. “Reasonably certain” is assessed internally based on economic, industry, company, strategic and contractual factors. The leases have remaining lease terms of 1 year to 15 years, some of which include options to extend the lease for up to 10 years, and some of which include options to terminate the lease within 1 year. Operating lease expense and amortization of finance lease ROU assets are recognized on a straight-line basis over the lease term as an operating expense. Finance lease interest expense is recorded as interest expense on the Company’s consolidated statements of operations. The Company accounts for leases acquired in business combinations by measuring the lease liability at the present value of the remaining lease payments as if the acquired lease were a new lease for the Company. This measurement includes recognition of a lease intangible for any below-market terms present in the leases acquired. The below-market lease intangible is included in the ROU asset on the consolidated balance sheets and are amortized over the remaining lease term. The Company has not acquired any leases with above-market terms. The Company has taken advantage of certain practical expedients offered to registrants at adoption of ASC 842. The Company does not apply the recognition requirements of ASC 842 to short-term leases. Instead, those lease payments are recognized in profit or loss on a straight-line basis over the lease term. Further, as a practical expedient, all lease contracts are accounted for as one single lease component, as opposed to separating lease and non-lease components to allocate the consideration within a single lease contract. Revenue Recognition Revenues are recognized when the satisfaction of the performance obligation occurs, in an amount that reflects the consideration the Company expects to collect in exchange for those services. To determine revenue recognition for the arrangements that the Company determines are within the scope of FASB ASC Topic 606, Revenue from Contracts with Customers, the Company performs the following five steps: (1) identify the contract(s) with a customer, (2) identify the performance obligations in the contract, (3) determine the transaction price, (4) allocate the transaction price to the performance obligations in the contract and (5) recognize revenue when (or as) the entity satisfies a performance obligation. See Note 2 for further discussion. Foreign Currency Transactions Prior to 2019, the Company’s international subsidiaries’ functional currency was the local currency and assets and liabilities were translated into U.S. dollars at the period-end exchange rate or historical rates, as appropriate. Consolidated statements of operations were translated at average exchange rates for the period, and the cumulative translation adjustments resulting from changes in exchange rates were included in the Company’s consolidated balance sheet as a component of additional paid-in capital. In 2019 and 2020, the Company’s international subsidiaries use the U.S. dollar as the functional currency, resulting in the Company not being subject to gains and losses from foreign currency translation of the subsidiary financial statements. The Company recognizes gains and losses from foreign currency transactions in the consolidated statements of operations. Net foreign currency transaction gains or losses were not material to the consolidated statements of operations for the periods presented. Concentration of Credit Risk Financial instruments that subject the Company to credit risk consist of cash, cash equivalents and marketable securities. As of December 31, 2020, the Company had cash and cash equivalents deposited in financial institutions in which the balances exceed the federal government agency insured limit of $250,000 by approximately $237.0 million. The Company has not experienced any losses in s

REVENUE

REVENUE	12 Months Ended
	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
REVENUE	REVENUE The Company’s revenue is primarily generated by its laboratory testing services utilizing its Cologuard, Oncotype IQ ® , and COVID-19 tests. The services are completed upon release of a patient’s test result to the ordering healthcare provider. The core principle of ASC 606 is that the Company recognizes revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the Company expects to collect in exchange for those goods or services. The Company recognizes revenues from its products in accordance with that core principle, and key aspects considered by the Company include the following: Contracts The Company’s customer is primarily the patient, but the Company does not enter into a formal reimbursement contract with a patient. The Company establishes a contract with a patient in accordance with other customary business practices, which is the point in time an order is received from a provider and a patient specimen has been returned to the laboratory for testing. Payment terms are a function of a patient’s existing insurance benefits, including the impact of coverage decisions with Center for Medicare & Medicaid Services (“CMS”) and applicable reimbursement contracts established between the Company and payers. However, when a patient is considered self-pay, the Company requires payment from the patient prior to the commencement of the Company’s performance obligations. The Company’s consideration can be deemed variable or fixed depending on the structure of specific payer contracts, and the Company considers collection of such consideration to be probable to the extent that it is unconstrained. Under the Company’s Laboratory Service Agreements (“LSA”) and Laboratory Reference Agreements (“LRA”) the Company contracts with a direct bill payer who is the customer for an agreed upon amount of laboratory testing services for a specified amount of time at a fixed reimbursement rate, and certain of the Company’s LSAs obligate the customer to pay for testing services prior to result. Performance obligations A performance obligation is a promise in a contract to transfer a distinct good or service (or a bundle of goods or services) to the customer. The Company’s contracts have a single performance obligation, which is satisfied upon rendering of services, which culminates in the release of a patient’s test result to the ordering healthcare provider. Or, in the context of some of the Company’s LSAs, the satisfaction of the performance obligation occurs when a specimen sample is not returned to the laboratory for processing before the end of the allotted testing window. The Company elects the practical expedient related to the disclosure of unsatisfied performance obligations, as the duration of time between providing testing supplies, the receipt of a sample, and the release of a test result to the ordering healthcare provider is far less than one year. Transaction price The transaction price is the amount of consideration that the Company expects to collect in exchange for transferring promised goods or services to a customer, excluding amounts collected on behalf of third parties (for example, some sales taxes). The consideration expected to be collected from a contract with a customer may include fixed amounts, variable amounts, or both. Fixed consideration is derived from the Company’s LSA, LRA, and direct bill payer contracts that exist between the Company and the direct bill payers. The contracted reimbursement rate is deemed to be fixed as the Company expects to fully collect all amounts billed under these relationships. Variable consideration is primarily derived from payer and patient billing and can result due to several factors such as the amount of contractual adjustments, any patient co-payments, deductibles or patient adherence incentives, the existence of secondary payers, and claim denials. The Company estimates the amount of variable consideration using the expected value method, which represents the sum of probability-weighted amounts in a range of possible consideration amounts. When estimating the amount of variable consideration, the Company considers several factors, such as historical collections experience, patient insurance eligibility and payer reimbursement contracts. The Company limits the amount of variable consideration included in the transaction price to the unconstrained portion of such consideration. In other words, the Company recognizes revenue up to the amount of variable consideration that is not subject to a significant reversal until additional information is obtained or the uncertainty associated with the additional payments or refunds is subsequently resolved. Differences between original estimates and subsequent revisions, including final settlements, represent changes in the estimate of variable consideration and are included in the period in which such revisions are made. Revenue recognized from changes in transaction prices was $9.6 million, $9.9 million and $15.0 million for the years ended December 31, 2020, 2019 and 2018, respectively. The Company monitors its estimates of transaction price to depict conditions that exist at each reporting date. If the Company subsequently determines that it will collect more or less consideration than it originally estimated for a contract with a patient, it will account for the change as an increase or decrease in the estimate of the transaction price (i.e., an upward or downward revenue adjustment) in the period identified. When the Company does not have significant historical experience or that experience has limited predictive value, the constraint over estimates of variable consideration may result in no revenue being recognized upon completion of the performance obligations associated with the Company's tests, with recognition, generally occurring at the date of cash receipt. Allocate transaction price The transaction price is allocated entirely to the performance obligation contained within the contract with a customer. Point in time recognition The Company’s single performance obligation is satisfied at a point in time. That point in time is defined as the date the Company releases a result to the ordering healthcare provider, or, in the context of some of the Company's LSAs, that point in time could be the date the allotted testing window ends if a specimen sample is not returned to the laboratory for processing. The point in time in which revenue is recognized by the Company signifies fulfillment of the performance obligation to the patient or direct bill payer. Disaggregation of Revenue The following table presents the Company's revenues disaggregated by revenue source: Year Ended December 31, (In thousands) 2020 2019 2018 Screening Medicare Parts B & C $ 365,471 $ 404,331 $ 254,431 Commercial 409,671 368,006 184,538 Other 39,925 37,783 15,493 Total Screening 815,067 810,120 454,462 Precision Oncology Medicare Parts B & C $ 157,166 $ 24,325 $ — Commercial 186,043 29,976 — International 77,484 11,444 — Other 19,800 428 — Total Precision Oncology 440,493 66,173 — COVID-19 Testing $ 235,831 $ — $ — Total $ 1,491,391 $ 876,293 $ 454,462 Screening revenue primarily includes laboratory service revenue from the Cologuard test while Precision Oncology revenue primarily includes laboratory service revenue from global Oncotype IQ products. Contract Balances The timing of revenue recognition, billings and cash collections results in billed accounts receivable and deferred revenue on the consolidated balance sheets. Generally, billing occurs subsequent to the release of a patient’s test result to the ordering healthcare provider, resulting in an account receivable. However, the Company sometimes receives advance payment from a patient or a direct bill payer before a test result is completed, resulting in deferred revenue. The deferred revenue recorded is recognized as revenue at the point in time results are released to the patient’s healthcare provider. Or, in the context of some of the Company’s LSAs, the satisfaction of the performance obligation occurs when a specimen sample is not returned to the laboratory for processing before the end of the allotted testing window. Deferred revenue balances are reported in other current liabilities in the Company’s consolidated balance sheets and were $25.0 million and $0.6 million as of December 31, 2020 and 2019, respectively. As of December 31, 2020, $24.2 million of the Company’s deferred revenue balance is a result of the billing terms pursuant to the existing COVID-19 LSAs with customers. Revenue recognized for the years ended December 31, 2020 and 2019, which was included in the deferred revenue balance at the beginning of each period was $0.2 million and $0.2 million, respectively. Practical Expedients The Company does not adjust the transaction price for the effects of a significant financing component, as at contract inception, the Company expects the collection cycle to be one year or less. The Company expenses sales commissions when incurred because the amortization period would have been one year or less. These costs are recorded within sales and marketing expenses in the Company’s consolidated statements of operations. The Company incurs certain other costs that are incurred regardless of whether a contract is obtained. Such costs are primarily related to legal services and patient communications (e.g. adherence reminder letters). These costs are expensed as incurred and recorded within general and administrative expenses in the Company’s consolidated statements of operations.

MARKETABLE SECURITIES

MARKETABLE SECURITIES	12 Months Ended
	Dec. 31, 2020
Cash and Cash Equivalents [Abstract]
MARKETABLE SECURITIES	MARKETABLE SECURITIES The following table sets forth the Company’s cash, cash equivalents, restricted cash, and marketable securities at December 31, 2020 and 2019: December 31, (In thousands) 2020 2019 Cash, cash equivalents, and restricted cash Cash and money market $ 901,294 $ 146,932 Cash equivalents 589,994 30,322 Restricted cash (1) 306 274 Total cash, cash equivalents and restricted cash 1,491,594 177,528 Marketable securities Available-for-sale debt securities 347,178 144,685 Equity securities 1,521 1,716 Total marketable securities 348,699 146,401 Total cash and cash equivalents, restricted cash and marketable securities $ 1,840,293 $ 323,929 _________________________________ (1) Restricted cash is included in other long-term assets on the consolidated balance sheets. There was no restricted cash at December 31, 2018. Available-for-sale debt securities at December 31, 2020 consisted of the following: (In thousands) Amortized Cost Gains in Accumulated Losses in Accumulated Other Comprehensive Income (Loss) (1) Estimated Fair Cash equivalents U.S. government agency securities $ 589,986 $ 8 $ — $ 589,994 Total cash equivalents 589,986 8 — 589,994 Marketable securities Corporate bonds 132,301 612 — 132,913 U.S. government agency securities 207,119 52 — 207,171 Asset backed securities 7,070 24 — 7,094 Total marketable securities 346,490 688 — 347,178 Total available-for-sale debt securities $ 936,476 $ 696 $ — $ 937,172 _________________________________ (1) Gains and losses in accumulated other comprehensive income (loss)("AOCI") are reported before tax impact. Available-for-sale debt securities at December 31, 2019 consisted of the following: (In thousands) Amortized Cost Gains in Accumulated Losses in Accumulated Estimated Fair Cash equivalents U.S. government agency securities $ 30,320 $ 2 $ — $ 30,322 Total cash equivalents 30,320 2 — 30,322 Marketable securities Corporate bonds 4,017 — (14) 4,003 U.S. government agency securities 140,745 10 (73) 140,682 Total marketable securities 144,762 10 (87) 144,685 Total available-for-sale debt securities $ 175,082 $ 12 $ (87) $ 175,007 _________________________________ (1) There was no tax impact on the gains and losses in accumulated income (loss) at December 31, 2019. The following table summarizes contractual underlying maturities of the Company’s available-for-sale debt securities at December 31, 2020: Due one year or less Due after one year through four years (In thousands) Cost Fair Value Cost Fair Value Cash equivalents U.S. government agency securities $ 589,986 $ 589,994 $ — $ — Total cash equivalents 589,986 589,994 — — Marketable securities U.S. government agency securities 199,988 199,994 7,131 7,177 Corporate bonds 100,837 101,122 31,464 31,791 Asset backed securities — — 7,070 7,094 Total marketable securities 300,825 301,116 45,665 46,062 Total available-for-sale securities $ 890,811 $ 891,110 $ 45,665 $ 46,062 There were no available-for-sale debt securities in an unrealized loss position as of December 31, 2020. The following table summarizes the gross unrealized losses and fair value of available-for-sale debt securities in an unrealized loss position as of December 31, 2019, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position: Less than 12 months 12 months or greater Total (In thousands) Fair Value Gross Unrealized Loss Fair Value Gross Unrealized Loss Fair Value Gross Unrealized Loss Marketable Securities Corporate bonds $ 4,003 $ (14) $ — $ — $ 4,003 $ (14) Asset backed securities 140,682 (73) — — 140,682 (73) Total $ 144,685 $ (87) $ — $ — $ 144,685 $ (87) The Company evaluates investments, including investments in privately-held companies, that are in an unrealized loss position for impairment as a result of credit loss. It was determined that no credit losses exist as of December 31, 2020 and 2019 because the change in market value for those securities in an unrealized loss position has resulted from fluctuating interest rates rather than a deterioration of the credit worthiness of the issuers. The Company recorded a realized gain on available-for-sale debt securities of $0.1 million, $3.4 million, and $0.4 million for the years ended December 31, 2020, 2019, and 2018, respectively, net of insignificant realized losses. The Company recorded a loss of $0.2 million and $0.2 million, respectively, from its equity securities for the years ended December 31, 2020 and 2019. The Company held no equity securities during the year ended December 31, 2018, and recorded no gain or loss. The gains and losses recorded are included in investment income, net in the Company’s consolidated statements of operations.

INVENTORY

INVENTORY	12 Months Ended
	Dec. 31, 2020
Inventory Disclosure [Abstract]
INVENTORY	INVENTORY Inventory consisted of the following: December 31, (In thousands) 2020 2019 Raw materials $ 43,083 $ 24,958 Semi-finished and finished goods 49,182 36,766 Total inventory $ 92,265 $ 61,724

PROPERTY, PLANT, AND EQUIPMENT

PROPERTY, PLANT, AND EQUIPMENT	12 Months Ended
	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
PROPERTY, PLANT, AND EQUIPMENT	PROPERTY, PLANT AND EQUIPMENT The estimated useful lives of property, plant and equipment are as follows: December 31, (In thousands) Estimated 2020 2019 Property, plant and equipment Land n/a $ 4,466 $ 4,466 Leasehold and building improvements (1) 117,865 80,352 Land improvements 15 years 4,864 1,766 Buildings 30 - 40 years 200,980 112,815 Computer equipment and computer software 3 years 73,296 65,323 Laboratory equipment 3 - 10 years 142,110 104,008 Furniture and fixtures 3 - 10 years 24,968 14,539 Assets under construction n/a 18,751 149,687 Property, plant and equipment, at cost 587,300 532,956 Accumulated depreciation (136,617) (77,631) Property, plant and equipment, net $ 450,683 $ 455,325 _________________________________ (1) Lesser of remaining lease term, building life, or estimated useful life. Depreciation expense for the years ended December 31, 2020, 2019, and 2018 was $69.4 million, $33.9 million, and $20.5 million, respectively.

INTANGIBLE ASSETS AND GOODWILL

INTANGIBLE ASSETS AND GOODWILL	12 Months Ended
	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
INTANGIBLE ASSETS AND GOODWILL	INTANGIBLE ASSETS AND GOODWILL Intangible Assets The following table summarizes the net-book-value and estimated remaining life of the Company's intangible assets as of December 31, 2020: (In thousands) Weighted Cost Accumulated Amortization Net Balance at December 31, 2020 Finite-lived intangible assets Trade name 14.9 $ 100,700 $ (7,258) $ 93,442 Customer relationships 12.8 2,700 (404) 2,296 Patents 3.7 10,441 (5,422) 5,019 Supply agreement 6.5 30,000 (4,527) 25,473 Acquired developed technology 9.0 814,171 (93,278) 720,893 Internally developed technology 2.2 2,121 (921) 1,200 Total finite-lived intangible assets 960,133 (111,810) 848,323 Internally developed technology in process n/a 103 — 103 Total intangible assets $ 960,236 $ (111,810) $ 848,426 The following table summarizes the net-book-value and estimated remaining life of the Company’s finite-lived intangible assets as of December 31, 2019: (In thousands) Weighted Cost Accumulated Amortization Net Balance at December 31, 2019 Finite-lived intangible assets Trade name 15.9 $ 100,700 $ (961) $ 99,739 Customer relationships 13.8 2,700 (224) 2,476 Patents 8.8 22,690 (5,975) 16,715 Supply agreement 7.5 30,000 (571) 29,429 Acquired developed technology 9.9 806,371 (12,344) 794,027 Internally developed technology 2.5 1,229 (336) 893 Total finite-lived intangible assets 963,690 (20,411) 943,279 In-process research and development n/a 200,000 — 200,000 Internally developed technology in process n/a 271 — 271 Total intangible assets $ 1,163,961 $ (20,411) $ 1,143,550 As of December 31, 2020, the estimated future amortization expense associated with the Company’s finite-lived intangible assets for each of the five succeeding fiscal years is as follows: (In thousands) 2021 $ 93,401 2022 93,196 2023 92,876 2024 92,422 2025 91,374 Thereafter 385,054 $ 848,323 The Company’s acquired intangible assets are being amortized on a straight-line basis over the estimated useful life. During the third quarter of 2020, the Company began discussions with Biocartis regarding the termination of its agreements with Biocartis related to the development of an in vitro diagnostic (“IVD”) version of the Oncotype DX Breast Recurrence Score ® test. As a result, and in connection with the preparation of the financial statements included in the Company's Form 10-Q for the period ended September 30, 2020, the Company recorded a non-cash, pre-tax impairment loss of $200.0 million related to the in-process research and development intangible asset that was initially recorded as part of the combination with Genomic Health. The impairment is recorded in intangible asset impairment charge in the consolidated statement of operations for the year ended December 31, 2020. The agreements with Biocartis were terminated in November 2020. During the third quarter of 2020, the Company abandoned certain research and development assets acquired through an asset purchase agreement with Armune Biosciences, Inc. in 2017. These assets were expected to complement the Company’s product pipeline and were expected to have alternative future uses at the time of acquisition; however, due to changes in strategic priorities and efforts during the third quarter of 2020, these assets are no longer expected to be utilized to advance the Company’s product pipeline. As a result, the Company wrote-off the gross cost basis of the intangible asset of $12.2 million and accumulated amortization of $2.5 million. This write-off resulted in a non-cash, pre-tax impairment loss of $9.7 million, which is recorded in intangible asset impairment charge in the consolidated statement of operations for the year ended December 31, 2020. There were no impairment losses for the years ended December 31, 2019 and 2018. Goodwill The change in the carrying amount of goodwill for the years ended December 31, 2020 and 2019 is as follows: (In thousands) Balance, January 1, 2019 (1) $ 17,279 Genomic Health acquisition 1,185,918 Balance, December 31, 2019 1,203,197 Paradigm & Viomics acquisition 30,431 Genomic Health acquisition adjustment (2) 4,044 Balance, December 31, 2020 $ 1,237,672 _________________________________ (1) The beginning balance represents the goodwill acquired from the acquisitions of Sampleminded, Inc. in 2017 and Biomatrica, Inc. in 2018 totaling $2.0 million and $15.3 million, respectively. (2) The Company recognized a measurement period adjustment to goodwill related to an increase in Genomic Health's pre-acquisition deferred tax liability due to finalization of certain income-tax related items.

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS The three levels of the fair value hierarchy established are as follows: Level 1 Quoted prices (unadjusted) in active markets for identical assets or liabilities that the Company has the ability to access as of the reporting date. Active markets are those in which transactions for the asset or liability occur in sufficient frequency and volume to provide pricing information on an ongoing basis. Level 2 Pricing inputs other than quoted prices in active markets included in Level 1, which are either directly or indirectly observable as of the reporting date. These include quoted prices for similar assets or liabilities in active markets and quoted prices for identical or similar assets or liabilities in markets that are not active. Level 3 Unobservable inputs that reflect the Company’s assumptions about the assumptions that market participants would use in pricing the asset or liability. Unobservable inputs shall be used to measure fair value to the extent that observable inputs are not available. The following table presents the Company’s fair value measurements as of December 31, 2020 along with the level within the fair value hierarchy in which the fair value measurements, in their entirety, fall. (In thousands) Fair value at December 31, 2020 Quoted Prices Significant Significant Cash, cash equivalents, and restricted cash Cash and money market $ 901,294 $ 901,294 $ — $ — U.S. government agency securities 589,994 — 589,994 — Restricted cash 306 306 — — Marketable securities Corporate bonds 132,913 — 132,913 — U.S. government agency securities 207,171 — 207,171 — Asset backed securities 7,094 — 7,094 — Equity securities 1,521 1,521 — — Liabilities Contingent consideration (2,477) — — (2,477) Total $ 1,837,816 $ 903,121 $ 937,172 $ (2,477) The following table presents the Company’s fair value measurements as of December 31, 2019 along with the level within the fair value hierarchy in which the fair value measurements, in their entirety, fall. (In thousands) Fair Value at December 31, 2019 Quoted Prices Significant Significant Cash and cash equivalents Cash and money market $ 146,932 $ 146,932 $ — $ — U.S. government agency securities 30,322 — 30,322 — Restricted cash 274 274 — — Marketable securities Corporate bonds 4,003 — 4,003 — U.S. government agency securities 140,682 — 140,682 — Equity securities 1,716 1,716 — — Liabilities Contingent consideration (2,879) — — (2,879) Total $ 321,050 $ 148,922 $ 175,007 $ (2,879) There have been no changes in valuation techniques or transfers between fair value measurement levels during the years ended December 31, 2020 and 2019. The fair value of Level 2 instruments classified as cash equivalents and marketable debt securities are valued using a third-party pricing agency where the valuation is based on observable inputs including pricing for similar assets and other observable market factors. The Company's marketable equity security investment in Biocartis is classified as a Level 1 instrument. See Note 11 for additional information on Biocartis. Contingent Consideration In connection with the Biomatrica acquisition, a contingent earn-out liability was created to account for an additional $20.0 million in contingent consideration that could be earned based upon certain revenue milestones being met. The following table provides a roll-forward of the fair values of the contingent consideration, which includes Level 3 measurements: (In thousands) Contingent consideration Balance, January 1, 2020 $ (2,879) Changes in fair value 325 Payments 77 Balance, December 31, 2020 $ (2,477) As of December 31, 2020, the fair value of the contingent earn-out liability is classified as a component of other long-term liabilities in the Company’s consolidated balance sheet. This fair value measurement of contingent consideration related to the Biomatrica acquisition was categorized as a Level 3 liability, as the measurement amount is based primarily on significant inputs not observable in the market. The Company evaluates the fair value of expected contingent consideration and the corresponding liability each annual reporting period using the Monte Carlo Method, which is consistent with the initial measurement of the expected Biomatrica Acquisition earn-out liability. The Company estimates projections during the earn-out period utilizing various potential pay-out scenarios. Probabilities were applied to each potential scenario and the resulting values were discounted using a rate that considers weighted average cost of capital as well as a specific risk premium associated with the riskiness of the earn-out itself, the related projections, and the overall business. Non-Marketable Equity Investments The Company has non-marketable equity investments which are initially recorded at the estimated fair value based on observable transactions. The Company has concluded it is not a primary beneficiary with regards to these investments and does not have the ability to exercise significant influence over the investees and thus has not consolidated the investees pursuant to the requirements of ASC 810, Consolidation. The Company will continue to assess its investments and future commitments to the investees and to the extent its relationship with the investees change and whether such change may require consolidation of the investees in future periods. The Company remeasures the fair value only when an observable transaction occurs during the period that would suggest a change in the carrying value of the investment. As of December 31, 2020 and 2019, the Company had non-marketable equity investments of $29.1 million and $11.8 million, respectively, which are classified as a component of other long-term assets in the Company’s consolidated balance sheets. As of December 31, 2020, the balance primarily consists of the Company’s preferred stock investments in 18,258,838 shares of Epic Sciences, Inc. ("Epic Sciences") and 5,025,764 shares of Thrive Earlier Detection Corp. (“Thrive”) of $10.8 million and $12.5 million, respectively. As of December 31, 2019, the balance consists of the Company’s preferred stock investments in Epic Sciences and Thrive Earlier Detection Corp. (“Thrive”) of $10.8 million and $1.0 million, respectively. The Company purchased 4.0 million shares of Series B Preferred Stock of Thrive for $10.0 million in July 2020. The Company previously held a $1.0 million investment in the Series A Preferred Stock of Thrive, which does not have a readily determinable fair value and therefore, the Company elected the measurement alternative. The rights and obligations of the Series B Preferred Stock are generally the same as the Series A Preferred Stock previously held indicating that the transactions are identical or similar investments. As a result, the Company recorded an unrealized gain of $1.5 million during the year ended December 31, 2020 in investment income, net on the Company’s consolidated statement of operations to revalue the Company’s initial investment to the value of the Series B Preferred Stock, which was the most recent observable transaction. As discussed in Note 22 below, the Company acquired Thrive in January 2021. There have been no other observable transactions during the years ended December 31, 2020 and 2019. Derivative Financial Instruments As of December 31, 2020 and 2019, the Company had open foreign currency forward contracts with notional amounts of $22.4 million and $17.9 million, respectively. The Company's foreign exchange derivative instruments are classified as Level 2 within the fair value hierarchy as they are valued using inputs that are observable in the market or can be derived principally from or corroborated by observable market data. The fair value of the foreign currency forward contracts was zero at December 31, 2020 and 2019, and there were no gains or losses recorded for the years ended December 31, 2020 and 2019. Fair Value of Long-Term Debt and Convertible Notes The Company measures the fair value of its convertible notes and long-term debt for disclosure purposes. The following table summarizes the Company’s outstanding convertible notes and long-term debt: December 31, 2020 December 31, 2019 (In thousands) Carrying Amount (1) Fair Value Carrying Amount (1) Fair Value 2028 Convertible notes (2) $ 806,587 $ 1,526,625 $ — $ — 2027 Convertible notes (2) 514,173 992,306 483,909 843,741 2025 Convertible notes (2) 255,464 601,744 319,696 592,482 Construction loan (3) 23,661 23,661 24,866 24,866 _________________________________ (1) The carrying amounts presented are net of debt discounts and debt issuance costs. See Note 9 and Note 10 of the consolidated financial statements for further information. (2) The fair values are based on observable market prices for this debt, which is traded in active markets and therefore is classified as a Level 2 fair value measurement. A portion of the 2025 convertible notes were settled in 2019 resulting in a decrease in the liability. (3) The carrying amount of the construction loan approximates fair value due to the short-term nature of this instrument. The construction loan is privately held with no public market for this debt and therefore is classified as a Level 3 fair value measurement. The change in the fair value was due to payments made on the loan resulting in a decrease in the liability.

ACCRUED LIABILITIES

ACCRUED LIABILITIES	12 Months Ended
	Dec. 31, 2020
Payables and Accruals [Abstract]
ACCRUED LIABILITIES	ACCRUED LIABILITIES Accrued liabilities at December 31, 2020 and 2019 consisted of the following: December 31, (In thousands) 2020 2019 Compensation $ 117,273 $ 95,166 Pfizer Promotion Agreement related costs 46,937 33,230 Professional fees 36,113 29,108 Other 20,735 13,976 Assets under construction 2,118 10,720 Research and trial related expenses 5,911 8,368 Licenses 4,517 2,761 $ 233,604 $ 193,329

LONG-TERM DEBT

LONG-TERM DEBT	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
LONG-TERM DEBT	LONG-TERM DEBT Construction Loan Agreement During December 2017, the Company entered into a loan agreement with Fifth Third Bank (formerly MB Financial Bank, N.A.) (the “Construction Loan Agreement”), which provides the Company with a non-revolving construction loan (the “Construction Loan”) of $25.6 million. The Company is using the Construction Loan proceeds to finance the construction of an additional clinical laboratory and related facilities in Madison, Wisconsin. The Construction Loan is collateralized by the additional clinical laboratory and related facilities. Pursuant to the Construction Loan Agreement, funds drawn will bear interest at a rate equal to the sum of the 1-month LIBOR rate plus 2.25 percent. Regular monthly payments are interest-only for the first 24 months, with further payments based on a 20-year amortization schedule. Amounts borrowed pursuant to the Construction Loan Agreement may be prepaid at any time without penalty. The maturity date of the Construction Loan Agreement is December 10, 2022. In November 2017, Fifth Third Bank, on behalf of the Company, issued an Irrevocable Standby Letter of Credit in the amount of $0.6 million in favor of the City of Madison, Wisconsin (the “City Letter of Credit”). The City Letter of Credit is deemed to have been issued pursuant to the Construction Loan Agreement. The amount of the City Letter of Credit will reduce, dollar for dollar, the amount available for borrowing under the Construction Loan Agreement. As a condition to Fifth Third’s initial advance of loan proceeds under the Construction Loan Agreement, the Company was required to first invest at least $16.4 million of its own cash into the construction project. The Company fulfilled its required initial investment and made its first draw on the Construction Loan in June 2018. In December 2019, the Company began making monthly payments towards the outstanding principal balance plus accrued interest. As of December 31, 2020 and 2019, the outstanding balance was $23.8 million and $25.0 million, respectively, from the Construction Loan, including $0.7 million of interest incurred, which is accrued for as an interest reserve and represents a portion of the loan balance. The Company capitalized the $0.7 million of interest to the construction project. The Company incurred approximately $0.2 million of debt issuance costs related to the Construction Loan, which are recorded as a direct deduction from the liability. The debt issuance costs are being amortized over the life of the Construction Loan. The Construction Loan Agreement was amended effective June 30, 2020 to include a financial covenant to maintain a minimum liquidity of $250.0 million and remove the minimum tangible net worth covenant. As of December 31, 2020, the Company is in compliance with the covenant included in the amended agreement. The table below represents the future principal obligations as of December 31, 2020. Amounts included in the table are in thousands: Year ending December 31 2021 $ 1,319 2022 22,431 Total $ 23,750 Tax Increment Financing Loan Agreements The Company entered into two separate Tax Increment Financing Loan Agreements (“TIFs”) in February 2019 and June 2019 with the City of Madison, Wisconsin. The TIFs provide for $4.6 million of financing in the aggregate. In return for the loans, the Company is obligated to create and maintain 500 full-time jobs over a five-year period, starting on the date of occupancy of the buildings constructed. In the event that the job creation goals are not met, the Company would be required to pay a penalty. The Company records the earned financial incentives as the full-time equivalent positions are filled. The amount earned is recorded as a liability and amortized as a reduction of operating expenses over a two-year period, which is the timeframe when the TIFs will be repaid through property taxes.

CONVERTIBLE DEBT

CONVERTIBLE DEBT	12 Months Ended
	Dec. 31, 2020
CONVERTIBLE DEBT
CONVERTIBLE DEBT	CONVERTIBLE NOTES Convertible note obligations included in the consolidated balance sheets consisted of the following: December 31, (In thousands) Coupon Interest Rate Effective Interest Rate Fair Value of Liability Component at Issuance (1) 2020 2019 2028 Convertible notes 0.375 % 5.2 % $ 790,608 $ 1,150,000 $ — 2027 Convertible notes 0.375 % 6.3 % 472,501 747,500 747,500 2025 Convertible notes 1.000 % 6.0 % 227,103 315,049 415,049 Total Convertible notes 2,212,549 1,162,549 Less: Debt discount (2) (608,685) (342,463) Less: Debt issuance costs (3) (27,640) (16,481) Net convertible debt including current maturities 1,576,224 803,605 Less: Current maturities (4) (255,464) — Net long-term convertible debt $ 1,320,760 $ 803,605 _________________________________ (1) As each of the convertible instruments may be settled in cash upon conversion, for accounting purposes, they were separated into a liability component and an equity component. The amount allocated to the equity component is the difference between the principal value of the instrument and the fair value of the liability component at issuance. The resulting debt discount is being amortized to interest expense at the respective effective interest rate over the contractual term of the debt. A portion of the 2025 Convertible Notes have been extinguished or converted. The fair value of the liability component at issuance reflected above represents the liability value at issuance for the applicable portion of the 2025 Notes which remain outstanding at December 31, 2020. The fair value of the liability component of the 2025 Notes at issuance was $654.8 million with the equity component being $267.9 million. (2) The unamortized discount consists of the following: December 31, (In thousands) 2020 2019 2028 Convertible notes $ 328,372 $ — 2027 Convertible notes 224,517 253,340 2025 Convertible notes 55,796 89,123 Total unamortized discount $ 608,685 $ 342,463 (3) Debt issuance costs consist of the following: December 31, (In thousands) 2020 2019 2028 Convertible notes $ 15,041 $ — 2027 Convertible notes 8,810 10,251 2025 Convertible notes 3,789 6,230 Total debt issuance costs $ 27,640 $ 16,481 (4) Based on the share price on trading days leading up to December 31, 2020, holders of the 2025 Convertible Notes will have the right to convert their debentures beginning on January 1, 2021. As a result, the 2025 Convertible Notes are included within convertible notes, net, current portion on the consolidated balance sheet. As of December 31, 2019, the 2025 Convertible Notes were not convertible and included within long-term convertible notes, net on the consolidated balance sheet. Issuances and Settlements In January 2018, the Company issued and sold $690.0 million in aggregate principal amount of 1.0% Convertible Notes (the “January 2025 Notes”) with a maturity date of January 15, 2025. The January 2025 Notes accrue interest at a fixed rate of 1.0% per year, payable semi-annually in arrears on January 15 and July 15 of each year, beginning on July 15, 2018. The net proceeds from the issuance of the January 2025 Notes were approximately $671.1 million, after deducting underwriting discounts and commissions and the offering expenses payable by the Company. In June 2018, the Company issued and sold an additional $218.5 million in aggregate principal amount of 1.0% Convertible Notes (the “June 2025 Notes”). The June 2025 Notes were issued under the same indenture pursuant to which the Company previously issued the January 2025 Notes (the “Indenture”). The January 2025 Notes and the June 2025 Notes (collectively, the “2025 Notes”) have identical terms (including the same January 15, 2025 maturity date) and will be treated as a single series of securities. The net proceeds from the issuance of the June 2025 Notes were approximately $225.3 million, after deducting underwriting discounts and commissions and the offering expenses payable by the Company. In March 2019, the Company issued and sold $747.5 million in aggregate principal amount of 0.375% Convertible Notes (the “2027 Notes”) with a maturity date of March 15, 2027. The 2027 Notes accrue interest at a fixed rate of 0.375% per year, payable semi-annually in arrears on March 15 and September 15 of each year, beginning on September 15, 2019. The net proceeds from the issuance of the 2027 Notes were approximately $729.5 million, after deducting underwriting discounts and commissions and the offering expenses payable by the Company. The Company utilized a portion of the proceeds from the issuance of the 2027 Notes to settle a portion of the 2025 Notes in privately negotiated transactions. In March 2019, the Company used cash of $494.1 million and an aggregate of 2.2 million shares of the Company’s common stock valued at $182.4 million for total consideration of $676.5 million to settle $493.4 million of the 2025 Notes, of which $375.0 million was allocated to the liability component, $300.8 million was allocated to the equity component, and $0.7 million was used to pay off interest accrued on the 2025 Notes. The consideration transferred was allocated to the liability and equity components of the 2025 Notes using the equivalent rate that reflected the borrowing rate for a similar non-convertible debt instrument immediately prior to settlement. The transaction resulted in a loss on settlement of convertible notes of $10.6 million, which is recorded in interest expense in the Company’s consolidated statement of operations. The loss represents the difference between (i) the fair value of the liability component and (ii) the sum of the carrying value of the debt component and any unamortized debt issuance costs at the time of repurchase. In February 2020, the Company issued and sold $1.15 billion in aggregate principal amount of 0.375% Convertible Notes (the “2028 Notes” and, collectively with the 2025 Notes and the 2027 Notes, the “Notes”) with a maturity date of March 1, 2028. The 2028 Notes accrue interest at a fixed rate of 0.375% per year, payable semi-annually in arrears on March 1 and September 1 of each year, beginning on September 1, 2020. The net proceeds from the issuance of the 2028 Notes were approximately $1.13 billion, after deducting underwriting discounts and commissions and the offering expenses payable by the Company. In February 2020, the Company used $150.1 million of the proceeds from the issuance of the 2028 Notes to settle $100.0 million of the 2025 Notes, of which $85.5 million was allocated to the liability component, $64.2 million, net of a tax impact of $0.3 million, was allocated to the equity component, and $0.1 million was used to pay off interest accrued on the 2025 Notes. The consideration transferred was allocated to the liability and equity components of the 2025 Notes using the equivalent rate that reflected the borrowing rate for a similar non-convertible debt instrument immediately prior to settlement. The transaction resulted in a loss on settlement of convertible notes of $8.0 million, which is recorded in interest expense in the Company’s consolidated statement of operations. The loss represents the difference between (i) the fair value of the liability component and (ii) the sum of the carrying value of the debt component and any unamortized debt issuance costs at the time of repurchase. Summary of Conversion Features Until the six-months immediately preceding the maturity date of the applicable series of Notes, each series of Notes is convertible only upon the occurrence of certain events and during certain periods, as set forth in the Indenture. The Notes will be convertible into cash, shares of the Company’s common stock (plus, if applicable, cash in lieu of any fractional share), or a combination of cash and shares of the Company’s common stock, at the Company’s election. On or after the date that is six-months immediately preceding the maturity date of the applicable series of Notes until the close of business on the second scheduled trading day immediately preceding the maturity date, holders may convert such Notes at any time. It is the Company’s intent and policy to settle all conversions through combination settlement. The initial conversion rate is 13.26, 8.96, and 8.21 shares of common stock per $1,000 principal amount for the 2025 Notes,2027 Notes, and 2028 Notes, respectively, which is equivalent to an initial conversion price of approximately $75.43, $111.66, and $121.84 per share of the Company’s common stock for the 2025 Notes, 2027 Notes, and 2028 Notes, respectively. The conversion rate is subject to adjustment upon the occurrence of certain specified events but will not be adjusted for accrued and unpaid interest. In addition, holders of the Notes who convert their Notes in connection with a “make-whole fundamental change” (as defined in the Indenture), will, under certain circumstances, be entitled to an increase in the conversion rate. If the Company undergoes a “fundamental change” (as defined in the Indenture), holders of the Notes may require the Company to repurchase for cash all or part of their Notes at a repurchase price equal to 100% of the principal amount of the Notes to be repurchased, plus accrued and unpaid interest. As of December 31, 2020, the 2025 Notes are classified as current on the Company's consolidated balance sheet. The holders of the 2025 Notes will have the right to convert their debentures beginning on January 1, 2021 based on the share price on trading days leading up to December 31, 2020. As of December 31, 2020, the 2027 and 2028 Notes are classified as long-term on the Company's consolidated balance sheet as the holders do not have the right to convert. During 2019, the holders of the 2025 Notes had the right to convert their debentures between July 1, 2019 and December 31, 2019, and 55 notes were converted during the period, which were settled through the issuance of common shares equivalent to the conversion rate with any fractional shares settled in cash. The 2025 Notes no longer met any of the conversion features as of December 31, 2019. The future convertibility and resulting balance sheet classification of this liability will be monitored at each quarterly reporting date and will be analyzed dependent upon market prices of the Company’s common stock during the prescribed measurement periods. In the event that the holders of the Notes have the election to convert the Notes at any time during the prescribed measurement period, the Notes would then be considered a current obligation and classified as such. Based on the closing price of our common stock of $132.49 on December 31, 2020, the if-converted values on our 2025, 2027, and 2028 Notes exceed the principal amount by $238.3 million, $139.4 million, and $100.5 million, respectively. Ranking of Convertible Notes The Notes are the Company’s senior unsecured obligations and (i) rank senior in right of payment to all of its future indebtedness that is expressly subordinated in right of payment to the Notes; equal in right of payment to all of the Company’s future liabilities that are not so subordinated, unsecured indebtedness; (ii) are effectively junior to all of our existing and future secured indebtedness and other secured obligations, to the extent of the value of the assets securing that indebtedness and other secured obligations; and (iii) are structurally subordinated to all indebtedness and other liabilities of the Company’s subsidiaries. The Company allocates total transaction costs of the Notes to the liability and equity components based on their relative values. Transaction costs attributable to the liability component are amortized to interest expense over the term of the Notes, and transaction costs attributable to the equity component are netted with the equity component in stockholders’ equity. The following table summarizes the original transaction costs at the time of issuance for each set of Notes and the respective allocation to the liability and equity components: (In thousands) January 2025 Notes June 2025 Notes 2027 Notes 2028 Notes Transaction costs allocated to liability component $ 13,569 $ 5,052 $ 11,395 $ 16,811 Transaction costs allocated to equity component 5,340 2,311 6,632 7,642 Total transaction costs $ 18,909 $ 7,363 $ 18,027 $ 24,453 The Notes do not contain any financial or operating covenants or any restrictions on the payment of dividends, the issuance of other indebtedness or the issuance or repurchase of securities by the Company. Interest expense includes the following: Year Ended December 31, (In thousands) 2020 2019 2018 Debt issuance costs amortization $ 4,207 $ 2,661 $ 2,273 Debt discount amortization 72,272 39,595 26,291 Loss on settlement of convertible notes 7,954 10,558 — Coupon interest expense 9,631 7,325 7,823 Total interest expense on convertible notes 94,064 60,139 36,387 Other interest expense 1,919 1,460 402 Total interest expense $ 95,983 $ 61,599 $ 36,789

LICENSE AND COLLABORATION AGREE

LICENSE AND COLLABORATION AGREEMENTS	12 Months Ended
	Dec. 31, 2020
LICENSE AGREEMENTS [Abstract]
LICENSE AND COLLABORATION AGREEMENTS	LICENSE AND COLLABORATION AGREEMENTS The Company licenses certain technologies that are, or may be, incorporated into its technology under several license agreements, as well as the rights to commercialize certain diagnostic tests through collaboration agreements. Generally, the license agreements require the Company to pay royalties based on net revenues received using the technologies and may require minimum royalty amounts or maintenance fees. Mayo In June 2009, the Company entered into a license agreement with Mayo Foundation for Medical Education and Research (“Mayo”). The Company’s license agreement with Mayo was most recently amended in September 2020. Under the license agreement, Mayo granted the Company an exclusive, worldwide license to certain Mayo patents and patent applications, as well as a non-exclusive, worldwide license with regard to certain Mayo know-how. The scope of the license covers any screening, surveillance or diagnostic test or tool for use in connection with any type of cancer, pre-cancer, disease or condition. The licensed Mayo patents and patent applications contain both method and composition claims that relate to sample processing, analytical testing and data analysis associated with nucleic acid screening for cancers and other diseases. The jurisdictions covered by these patents and patent applications include the U.S., Australia, Canada, the European Union, China, Japan and Korea. Under the license agreement, the Company assumed the obligation and expense of prosecuting and maintaining the licensed Mayo patents and is obligated to make commercially reasonable efforts to bring to market products using the licensed Mayo intellectual property. Pursuant to the Company’s agreement with Mayo, the Company is required to pay Mayo a low single-digit royalty on the Company’s net sales of current and future products using the licensed Mayo intellectual property each year during the term of the Mayo agreement. The January 2016 amendment to the Mayo license agreement established various low-single-digit royalty rates on net sales of current and future products and clarified how net sales will be calculated. As part of the January 2016 and October 2017 amendments, the royalty rate on the Company's net sales of the Cologuard test increased but the rate remains a low-single-digit percentage of net sales. In addition to the royalties described above, the Company is required to pay Mayo cash of $0.2 million, $0.8 million and $2.0 million upon each product using the licensed Mayo intellectual property reaching $5.0 million, $20.0 million and $50.0 million in cumulative net sales, respectively. As part of the most recent amendment, the Company agreed to pay Mayo an additional $6.3 million, payable in five annual installments, through 2024. The Company paid Mayo the first annual installment of $1.3 million in the third quarter of 2020 and will make subsequent annual payments in the first quarter of the year beginning in January 2021. The license agreement will remain in effect, unless earlier terminated by the parties in accordance with the agreement, until the last of the licensed patents expires in 2038 (or later, if certain licensed patent applications are issued). However, if the Company is still using the licensed Mayo know-how or certain Mayo-provided biological specimens or their derivatives on such expiration date, the term shall continue until the earlier of the date the Company stops using such know-how and materials and the date that is five years after the last licensed patent expires. The license agreement contains customary termination provisions and permits Mayo to terminate the license agreement if the Company sues Mayo or its affiliates, other than any such suit claiming an uncured material breach by Mayo of the license agreement. In addition to granting the Company a license to the covered Mayo intellectual property, Mayo provides the Company with product development and research and development assistance pursuant to the license agreement and other collaborative arrangements. In September 2020, Mayo also agreed to make available certain personnel to provide such assistance through January 2025. In connection with this collaboration, the Company incurred charges of $3.9 million, $4.8 million, and $4.5 million for the years ended December 31, 2020, 2019, and 2018, respectively. The charges incurred in connection with this collaboration are recorded in research and development expenses in the Company's consolidated statements of operations. Hologic In October 2009, the Company entered into a technology license agreement with Hologic, Inc. (“Hologic”). Under the license agreement, Hologic granted the Company an exclusive, worldwide license within the field of human stool based colorectal cancer and pre-cancer detection or identification with regard to certain Hologic patents, patent applications and improvements, including Hologic’s Invader detection chemistry (the “Covered Hologic IP”). The license agreement also provided the Company with non-exclusive, worldwide licenses to the Covered Hologic IP within a field covering clinical diagnostic purposes relating to colorectal cancer (including cancer diagnosis, treatment, monitoring or staging) and the field of detection or identification of colorectal cancer and pre-cancers through means other than human stool samples. In December 2012, the Company entered into an amendment to this license agreement with Hologic pursuant to which Hologic granted the Company a non-exclusive worldwide license to the Covered Hologic IP within the field of any disease or condition within, related to or affecting the gastrointestinal tract and/or appended mucosal surfaces. The Company is required to pay Hologic a low single-digit royalty on the Company’s net sales of products using the Covered Hologic IP. Epic Sciences In June 2016, Genomic Health (now a wholly-owned subsidiary of the Company) entered into a collaboration agreement with Epic Sciences, which was superseded and replaced in March 2019 by a license agreement and laboratory services agreement with Epic Sciences, under which Genomic Health was granted exclusive distribution rights to commercialize Epic Sciences’ AR-V7 Nucleus Detect ® test in the United States, which is marketed as Oncotype DX AR-V7 Nucleus Detect ® . The Company has primary responsibility, in accordance with applicable laws and regulations, for marketing and promoting the test, order fulfillment, billing and collections of receivables, claims appeals, customer support, and providing and maintaining order management systems for the test. Epic Sciences is responsible for performing all tests, performing studies including analytic and clinical validation studies, and seeking Medicare coverage and a Medicare payment rate from the CMS for the test. The license and laboratory service agreement has a term of 10 years from June 2016, unless terminated earlier under certain circumstances. The Oncotype DX AR-V7 Nucleus Detect test became commercially available in February 2018. The Company recognizes revenues for the test performed under this arrangement and Epic Sciences receives a fee per test performed that represents the fair market value for the testing services they perform. Biocartis In September 2017, Genomic Health entered into an exclusive license and development agreement with Biocartis, a molecular diagnostics company based in Belgium, to develop and commercialize an IVD version of the Oncotype DX Breast Recurrence Score test on the Biocartis Idylla platform. Under the terms of the license and development agreement, the Company had an exclusive, worldwide, royalty-bearing license to develop and commercialize an IVD version of the Oncotype DX Breast Recurrence Score test on the Biocartis Idylla platform, and certain options to expand the collaboration . Pursuant to the license and development agreement, Genomic Health recorded a one-time upfront license and option fee of $3.2 million. In December 2017, Genomic Health purchased 270,000 ordinary shares of Biocartis, a public company listed on the Euronext exchange, for a total cost of $4.0 million. This investment was subject to a lock-up agreement that expired in December 2018. The investment has been recognized at fair value, which the Company estimated to be $1.5 million as of December 31, 2020 and is included in marketable securities on the Company's consolidated balance sheet. In October 2020, the Company and Biocartis agreed to terminate all agreements between them with a mutual release. As part of the termination, the Company made a payment of $12.0 million and returned certain equipment to Biocartis. The remaining net book value of the equipment was previously written off when it was determined that the agreement with Biocartis would be terminated. The termination payment and equipment write-off are both recorded in general and administrative expenses on the Company's consolidated statement of operations. Ludwig Institute for Cancer Research Ltd ("Ludwig") Through the acquisition of Base Genomics Limited ("Base"), the Company acquired a worldwide exclusive license agreement with Ludwig for use of patents and know-how. The license is designed to leverage technology related to DNA methylation detection and bisulfite sequencing for product research, development and commercialization. The agreement terms include low single-digit sales-based royalties on the Company’s net sales of products using the technology. The license agreement will remain in effect, unless earlier terminated by the parties in accordance with the agreement, until the tenth anniversary of the first commercial sale.

PFIZER PROMOTION AGREEMENT

PFIZER PROMOTION AGREEMENT	12 Months Ended
	Dec. 31, 2020
PFIZER PROMOTION AGREEMENT
PFIZER PROMOTION AGREEMENT	PFIZER PROMOTION AGREEMENTIn August 2018, the Company entered into a Promotion Agreement (the “Original Promotion Agreement”) with Pfizer, Inc. (“Pfizer”), which was amended and restated in October 2020 (the "Restated Promotion Agreement"). The Restated Promotion Agreement extends the relationship between the Company and Pfizer and restructures the manner in which the Company compensates Pfizer for promotion of the Cologuard test through a service fee, and provision of certain other sales and marketing services related to the Cologuard test. The Restated Promotion Agreement also includes additional fixed and performance-related fees, some of which retroactively went into effect on April 1, 2020. All payments to Pfizer are recorded in sales and marketing in the Company's consolidated statements of operations. The Company incurred charges of $85.3 million, $68.9 million and $5.8 million for promotion, sales and marketing services performed by Pfizer on behalf of the Company during the years ended December 31, 2020, 2019 and 2018, respectively. Under the Original Promotion Agreement, the service fee was calculated based on incremental gross profits over specified baselines during the term. The Company incurred charges of $68.5 million and $4.8 million for the service fee during the years ended December 31, 2019 and 2018, respectively. Under the Restated Promotion Agreement, the service fee was revised to a fee-for-service model, and includes certain fixed fees and performance-related bonuses. The Company incurred charges of $51.2 million for the service fee during the year ended December 31, 2020. The performance-related bonuses are contingent upon the achievement of certain annual performance criteria with any applicable expense being recognized ratably upon achievement of the payment becoming probable. During 2022, and contingent upon the achievement of certain Cologuard test revenue metrics during 2021, the Company will pay Pfizer a royalty based on a low single-digit royalty rate applied to actual 2022 Cologuard test revenues. The term of the Restated Promotion Agreement runs through December 31, 2022.

STOCKHOLDERS' EQUITY

STOCKHOLDERS' EQUITY	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
STOCKHOLDERS' EQUITY	STOCKHOLDERS' EQUITY Amendment to Certificate of Incorporation In July 2020, the Company filed a Certificate of Amendment (the “Certificate of Amendment”) to its Sixth Amended and Restated Certificate of Incorporation with the Secretary of State of the State of Delaware to increase the number of authorized shares of the Company’s common stock from 200 million to 400 million shares. The Certificate of Amendment was approved by the Company’s stockholders at the Company’s 2020 annual meeting in July 2020. Convertible Notes Settlement Stock Issuance In March 2019, the Company used cash of $494.1 million and an aggregate of 2.2 million shares of the Company’s common stock valued at $182.4 million for total consideration of $676.5 million to settle $493.4 million of the 2025 convertible notes. Refer to Note 10 for further discussion of this settlement transaction. Genomic Health Combination Stock Issuance In November 2019, the Company completed the combination with Genomic Health in a cash and stock transaction valued at $2.47 billion. Of the $2.47 billion purchase price, $1.41 billion was settled through the issuance of 17.0 million shares of common stock. The Company incurred $0.4 million in stock issuance costs as part of the transaction. Refer to Note 19 for further discussion of the consideration transferred as part of the combination with Genomic Health. Paradigm Diagnostics, Inc. ("Paradigm") and Viomics, Inc. ("Viomics") Acquisition Stock Issuance In March 2020, the Company completed the acquisitions of Paradigm and Viomics. The purchase price for these acquisitions consisted of cash and stock valued at $40.4 million. Of the $40.4 million purchase price, $32.2 million is expected to be settled through the issuance of 0.4 million shares of common stock. Of the $32.2 million that will be settled through the issuance of common stock, $28.8 million was issued as of December 31, 2020, and the remainder was withheld and may become issuable as additional merger consideration on June 3, 2021. Registered Direct Offering In October 2020, the Company entered into securities purchase agreements with a limited number of institutional investors for the registered direct offering of 8.6 million shares of common stock at a price of $101.00 per share. The Company received, in the aggregate, approximately $861.7 million of net proceeds from the offering, after deducting $7.5 million for the offering expenses and other stock issuance costs paid by the Company. Changes in Accumulated Other Comprehensive Income (Loss) The amount recognized in AOCI for the years ended December 31, 2020, 2019 and 2018 were as follows: (In thousands) Cumulative Unrealized Accumulated Balance, January 1, 2018 $ (61) $ (689) $ (750) Other comprehensive income (loss) before reclassifications 36 (1,025) (989) Amounts reclassified from accumulated other comprehensive loss — 317 317 Net current period change in accumulated other comprehensive income (loss) (1) 36 (708) (672) Balance at December 31, 2018 $ (25) $ (1,397) $ (1,422) Other comprehensive income (loss) before reclassifications — 681 681 Amounts reclassified from accumulated other comprehensive loss — 641 641 Net current period change in accumulated other comprehensive income (loss) (1) — 1,322 1,322 Balance at December 31, 2019 $ (25) $ (75) $ (100) Other comprehensive income (loss) before reclassifications — 771 771 Amounts reclassified from accumulated other comprehensive loss 25 — 25 Net current period change in accumulated other comprehensive income (loss) 25 771 796 Balance at Income tax expense related to items of other comprehensive income — (170) (170) Balance at December 31, 2020 $ — $ 526 $ 526 _________________________________ (1) There was no tax impact from the amounts recognized in AOCI for the years ended December 31, 2019 and 2018. Amounts reclassified from accumulated other comprehensive loss for the years ended December 31, 2020, 2019 and 2018 were as follows: Year Ended December 31, Details about AOCI Components (In thousands) Affected Line Item in the 2020 2019 2018 Change in value of available-for-sale investments Sales and maturities of available-for-sale investments Investment income $ — $ 641 $ 317 Foreign currency adjustment General and administrative 25 — — Total reclassifications $ 25 $ 641 $ 317

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
STOCK-BASED COMPENSATION	STOCK-BASED COMPENSATION Stock-Based Compensation Plans The Company maintains the following plans for which awards were granted from in 2020: the 2010 Omnibus Long-Term Incentive Plan (As Amended and Restated Effective July 27, 2017), the 2019 Omnibus Long-Term Incentive Plan, the 2010 Employee Stock Purchase Plan, and the 2016 Inducement Award Plan. The Company also maintained the 2000 Stock Option and Incentive Plan, of which the final options were exercised in 2020. These plans are collectively referred to as the “Stock Plans”. The Stock Plans are administered by the compensation committee of the Company’s board of directors. The plans for share-based equity awards provide that upon an acquisition of the Company, all equity will accelerate by a period of one year. In addition, upon the termination of an employee without cause or for good reason prior to the first anniversary of the completion of the acquisition, all equity awards then outstanding under the respective plan held by that employee will immediately vest. 2000 Stock Option and Incentive Plan. The Company adopted the 2000 Stock Option and Incentive Plan (the “2000 Option Plan”) on October 17, 2000 to grant share-based awards to employees, officers, directors, consultants and advisors. Awards granted under the 2000 Option Plan may include incentive stock options, as defined under the Internal Revenue Code, non-qualified options, restricted stock awards and other stock awards in amounts and with terms and conditions determined by the compensation committee of the Company’s board of directors, subject to the provisions of the 2000 Option Plan. The 2000 Option Plan expired October 17, 2010 and after such date no further awards could be granted under the plan. Options granted under the 2000 Option Plan expire ten years from the date of grant. Grants made from the 2000 Option Plan generally vest over a period of three 2010 Omnibus Long-Term Incentive Plan. The Company adopted the 2010 Omnibus Long-Term Incentive Plan (the “2010 Stock Plan”) on July 16, 2010 to grant share-based awards to employees, officers, directors, consultants and advisors. Awards granted under the 2010 Stock Plan may include incentive stock options, as defined under the Internal Revenue Code, non-qualified options, restricted stock awards and other stock awards in amounts and with terms and conditions determined by the compensation committee of the Company’s board of directors, subject to the provisions of the 2010 Stock Plan. The 2010 Stock Plan expired on July 16, 2020 and after such date no further awards may be granted under the plan. Options granted under the 2010 Stock Plan expire ten years from the date of grant. Grants made from the 2010 Stock Plan generally vest over a period of three 2019 Omnibus Long-Term Incentive Plan. The Company adopted the 2019 Omnibus Long-Term Incentive Plan (the “2019 Stock Plan”) on July 25, 2019 to grant share-based awards to employees, officers, directors, consultants and advisors. Awards granted under the 2019 Stock Plan may include incentive stock options, as defined under the Internal Revenue Code, non-qualified options, restricted stock awards and other stock awards in amounts and with terms and conditions determined by the compensation committee of the Company’s board of directors, subject to the provisions of the 2019 Stock Plan. The 2019 Stock Plan will expire on July 25, 2029 and after such date no further awards may be granted under the plan. Options granted under the 2019 Stock Plan expire ten years from the date of grant. Grants made from the 2019 Stock Plan generally vest over a period of three 2016 Inducement Award Plan. The Company adopted the 2016 Inducement Award Plan (the “2016 Inducement Plan”) on January 25, 2016 to grant share-based awards to employees who were not previously an employee of the Company or any of its Subsidiaries. Awards granted under the 2016 Inducement Plan may include grant incentive stock options, as defined under the Internal Revenue Code, non-qualified options, restricted stock awards and other stock awards in amounts and with terms and conditions determined by the compensation committee of the Company’s board of directors, subject to the provisions of the 2016 Inducement Plan. The 2016 Inducement Plan expired on July 27, 2017, and after such date no further awards could be granted under the plan. Options granted under the 2016 Inducement Plan expire ten years from the date of grant. Grants made from the 2016 Inducement Plan generally vest over a period of three 2010 Employee Stock Purchase Plan. The 2010 Employee Stock Purchase Plan (the “2010 Purchase Plan”) was adopted by the Company on July 16, 2010 to provide participating employees the right to purchase shares of common stock at a discount through a series of offering periods. The 2010 Purchase Plan will expire on October 31, 2030. The Company’s stockholders approved amendments to the 2010 Employee Stock Purchase Plan to increase the number of shares available for purchase thereunder by 500,000 shares and 2,000,000 shares on July 24, 2014 and July 28, 2016, respectively. At December 31, 2020, there were 759,015 shares of common stock available for purchase by participating employees under the 2010 Purchase Plan. Generally, all employees whose customary employment is more than 20 hours per week and more than five months in any calendar year are eligible to participate in the 2010 Purchase Plan. Participating employees authorize an amount, between 1 percent and 15 percent of the employee’s compensation, to be deducted from the employee’s pay during the offering period. On the last day of the offering period, the employee is deemed to have exercised the employee’s option to purchase shares of Company common stock, at the option exercise price, to the extent of accumulated payroll deductions. Under the terms of the 2010 Purchase Plan, the option exercise price is an amount equal to 85 percent of the fair market value, as defined under the 2010 Purchase Plan, and no employee can purchase more than $25,000 of Company common stock under the 2010 Purchase Plan in any calendar year. Rights granted under the 2010 Purchase Plan terminate upon an employee’s voluntary withdrawal from the 2010 Purchase Plan at any time or upon termination of employment. At December 31, 2020, there were 2,040,985 cumulative shares issued under the 2010 Purchase Plan. Stock-Based Compensation Expense A summary of non-cash stock-based compensation expense by expense category included in the Company's consolidated statements of operations for the years ended December 31, 2020, 2019, and 2018 is as follows: Year Ended December 31, (In thousands) 2020 2019 2018 Cost of sales $ 12,852 $ 5,799 $ 3,531 Research and development 19,976 17,196 10,189 General and administrative 75,999 64,222 34,181 Sales and marketing 44,079 21,266 12,363 Total stock-based compensation $ 152,906 $ 108,483 $ 60,264 As of December 31, 2020, there was approximately $262.5 million of expected total unrecognized compensation cost related to non-vested share-based compensation arrangements granted under all equity compensation plans. The Company expects to recognize that cost over a weighted average period of 2.63 years. In connection with the April 2018 transition of the Company’s former Chief Operating Officer, the Company accelerated the vesting of 69,950 shares under his previously unvested stock options and 54,350 shares under his previously unvested restricted stock units whereby such unvested stock options and unvested restricted stock units vest on December 31, 2018. It was determined that the continuing service to be provided by the Company’s Chief Operating Officer to the Company through December 31, 2018 was substantive and, as a result, the Company recognized the additional non-cash stock-based compensation expense for the modified awards evenly over the transition term of April 25, 2018 to December 31, 2018. During the year ended December 31, 2018, the Company recorded $3.9 million of non-cash stock-based compensation expense for the modified awards. In connection with the combination with Genomic Health, the Company accelerated the vesting of shares of previously unvested stock options and restricted stock units for employees with qualifying termination events. During the year ended December 31, 2020, the Company accelerated 83,593 shares of previously unvested stock options and 93,770 shares of previously unvested restricted stock units. During the year ended December 31, 2019, the Company accelerated 364,281 shares of previously unvested stock options and 70,138 shares of previously unvested restricted stock units. During the years ended December 31, 2020 and 2019, the Company recorded $9.7 million and $21.6 million, respectively, of non-cash stock-based compensation expense for the accelerated awards. Stock Options The Company determines the fair value of each service-based option award on the date of grant using the Black-Scholes option-pricing mode, which utilizes several key assumptions which are disclosed in the following table: Year Ended December 31 2020 2019 2018 Option Plan Shares Risk-free interest rates 1.26% - 1.47% 2.54% - 2.59% 2.73% - 2.79% Expected term (in years) 6.15 6.28 5.45 - 6.44 Expected volatility 65.67% - 65.71% 64.95% - 64.99% 61.82% - 66.17% Dividend yield 0% 0% 0% A summary of stock option activity under the Stock Plans is as follows: Options Shares Weighted Weighted Aggregate (Aggregate intrinsic value in thousands) Outstanding, January 1, 2020 2,700,293 $ 34.01 6.7 Granted 309,143 97.66 Exercised (707,013) 39.07 Forfeited (71,364) 82.76 Outstanding, December 31, 2020 2,231,059 $ 39.67 6.0 $ 207,090 Vested and expected to vest, December 31, 2020 2,231,059 $ 39.67 6.0 $ 207,090 Exercisable, December 31, 2020 1,399,721 $ 22.53 4.9 $ 153,912 _________________________________ (1) The weighted average grant date fair value of options granted during the years ended December 31, 2020, 2019, and 2018 was $58.57, $57.11, and $24.55. (2) The total intrinsic value of options exercised during the years ended December 31, 2020, 2019, and 2018 was $40.6 million, $52.0 million, and $53.0 million, respectively, determined as of the date of exercise. The Company received approximately $27.1 million, $8.8 million, and $6.6 million from stock option exercises during the years ended December 31, 2020, 2019 and 2018, respectively. Restricted Stock and Restricted Stock Units The fair value of restricted stock and restricted stock units is determined on the date of grant using the closing stock price on that day. A summary of restricted stock and restricted stock unit activity is as follows: Restricted Weighted Outstanding, January 1, 2020 3,800,722 $ 58.68 Granted 2,236,535 92.55 Released (1) (1,731,631) 50.67 Forfeited (337,412) 81.36 Outstanding, December 31, 2020 3,968,214 $ 79.38 _________________________________ (1) The fair value of restricted stock units vested and converted to shares of the Company's common stock was $152.4 million, $173.8 million, and $63.8 million for the years ended December 31, 2020, 2019, and 2018, respectively. (2) The weighted average grant date fair value of the restricted stock units granted during the years ended December 31, 2019 and 2018 was $93.20, and $50.45, respectively. Performance Share Units The Company issued performance-based equity awards to certain employees which vest upon the achievement of certain performance goals, including financial performance targets and operational milestones. In June 2020 and December 2020, the Company modified certain of the operational milestones and financial performance targets, respectively, within the outstanding performance-based equity awards, which were not deemed to have an impact on vesting and no incremental stock-based compensation expense was recorded for the year ended December 31, 2020. This modification impacted awards held by 36 employees. A summary of performance share unit activity is as follows: Performance Share Units (2) Weighted Outstanding, December 31, 2019 583,283 $ 93.40 Granted 35,232 90.17 Released (1) — — Forfeited — — Outstanding, December 31, 2020 618,515 $ 93.22 _________________________________ (1) The fair value of performance share units vested and converted to shares of the Company's common stock was $183.8 million for the year ended December 31, 2019. There were no performance share units vested and converted to shares of the Company's common stock during the years ended December 31, 2020 and 2018. (2) Participants may ultimately earn between zero and 200% of the target number of performance share units granted based on the degree of achievement of the performance criteria. The performance share units listed above assumes attainment of maximum payout rates as set forth in the performance criteria. Applying actual or expected payout rates, the number of outstanding performance share units as of December 31, 2020 was 158,958. (3) The weighted average grant date fair value of the performance share units granted during the years ended December 31, 2019 was $93.40. There were no performance share units granted during the year ended December 31, 2018. Employee Stock Purchase Plan ("ESPP") A summary of ESPP activity is as follows: Year Ended December 31, (in thousands, except share and per share amounts) 2020 2019 2018 Shares issued under the 2010 Purchase Plan 301,064 176,458 346,609 Cash received under the 2010 Purchase Plan $ 18,355 $ 8,396 $ 4,895 Weighted average fair value per share of stock purchase rights granted during the period $ 32.57 $ 29.21 $ 20.47 The 301,064 shares issued during the year ended December 31, 2020 were as follows: Offering period ended Number of Shares Weighted Average price per Share April 30, 2020 167,921 $ 57.95 November 2, 2020 133,143 $ 64.35 The fair value of ESPP shares is based on the assumptions in the following table: Year Ended December 31, 2020 2019 2018 ESPP Shares Risk-free interest rates 0.11% - 0.2% 1.6% - 2.4% 2.1% - 2.8% Expected term (in years) 0.5 - 2 0.4 - 2 0.5 - 2 Expected volatility 61.59% - 89.0% 43.2% - 57.6% 51.7% - 65.4% Dividend yield 0% 0% 0% Shares Reserved for Issuance The Company has reserved shares of its authorized common stock for issuance pursuant to its employee stock purchase and equity plans, including all outstanding stock option grants noted above at December 31, 2020, as follows: Shares reserved for issuance 2019 Stock Plan 11,898,737 2010 Purchase Plan 759,015 12,657,752

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Leases The components of lease expense were as follows: Year Ended December 31, (In thousands) 2020 2019 Finance lease cost Amortization of right-of-use assets $ 1,935 $ 27 Interest on lease liabilities 383 2 Operating lease cost 22,551 9,200 Short-term lease cost 356 219 Variable lease cost 2,703 896 Total Lease Cost $ 27,928 $ 10,344 Supplemental disclosure of cash flow information related to the Company's cash and non-cash activities with its leases are as follows: Year Ended December 31, (In thousands) 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 17,531 $ 9,641 Operating cash flows from finance leases 381 1 Finance cash flows from finance leases 1,756 15 Non-cash investing and financing activities: Right-of-use assets obtained in exchange for new operating lease liabilities (1) 13,261 51,030 Right-of-use assets obtained in exchange for new finance lease liabilities 20,349 237 Weighted-average remaining lease term - operating leases (in years) 8.75 9.80 Weighted-average remaining lease term - finance leases (in years) 3.68 1.20 Weighted-average discount rate - operating leases 6.80 % 6.80 % Weighted-average discount rate - finance leases 5.67 % 5.60 % _________________________________ (1) For the year ended December 31, 2019, this includes right-of-use assets obtained from the initial adoption of ASC 842 of approximately $17.9 million. As of December 31, 2020 and 2019, the Company’s right-of-use assets from operating leases are $125.9 million and $126.4 million, respectively, which are reported in operating lease right-of-use assets in the Company’s consolidated balance sheet. As of December 31, 2020, the Company has outstanding lease obligations of $132.6 million, of which $11.5 million is reported in operating lease liabilities, current portion and $121.1 million is reported in operating lease liabilities, less current portion in the Company’s consolidated balance sheet. As of December 31, 2019, the Company had outstanding lease obligations of $126.6 million, of which $7.9 million is reported in operating lease liabilities, current portion and $118.7 million is reported in operating lease liabilities, less current portion in the Company’s consolidated balance sheet. The Company calculates its incremental borrowing rates for specific lease terms, used to discount future lease payments, as a function of the U.S. Treasury rate and an indicative Moody’s rating for operating leases. As of December 31, 2020 and 2019, the Company’s right-of-use assets from finance leases are $20.6 million and $0.3 million, respectively, which are reported in other long-term assets, net in the Company’s consolidated balance sheets. As of December 31, 2020, the Company has outstanding finance lease obligations of $18.7 million, of which $4.7 million is reported in other current liabilities other long-term liabilities sheets. As of December 31, 2019, the Company had outstanding finance lease obligations of $0.2 million, of which $32,000 is reported in other current liabilities and $0.2 million is reported in other long-term liabilities in the Company’s consolidated balance sheets. The Company calculates its incremental borrowing rates for specific lease terms, used to discount future lease payments, as a function of the U.S. Treasury rate and an indicative Moody’s rating for finance leases. Maturities of operating lease liabilities on an annual basis as of December 31, 2020 were as follows (amounts in thousands): (In thousands) 2021 $ 19,881 2022 19,596 2023 21,306 2024 21,257 2025 19,338 Thereafter 79,141 Total minimum lease payments 180,519 Imputed interest (47,961) Total $ 132,558 Maturities of finance lease liabilities on an annual basis as of December 31, 2020 were as follows (amounts in thousands): (In thousands) 2021 $ 5,674 2022 5,635 2023 5,525 2024 3,819 2025 53 Thereafter — Total minimum lease payments 20,706 Imputed interest (1,961) Total $ 18,745 The Company executed a lease agreement for a new facility in Redwood City, California in 2020 that will commence in February 2021. The Company anticipates to recognize $8.2 million for the operating lease right-of-use assets and $8.3 million for the operating lease liabilities in the consolidated balance sheet, respectively, upon commencement of the lease. Rent expense included in the accompanying consolidated statements of operations was approximately $3.6 million for the year ended December 31, 2018. Legal Matters The Company is currently responding to civil investigative demands initiated by the United States Department of Justice (“DOJ”) concerning (1) Genomic Health's compliance with the Medicare Date of Service billing regulations and (2) allegations that the Company offered or gave gift cards to patients in exchange for returning the Cologuard screening test, in violation of the Federal Anti-Kickback Statute and False Claims Act. The Company has been cooperating with these inquiries and has produced documents in response thereto. Adverse outcomes from these investigations could include the Company being required to pay treble damages, incur civil and criminal penalties, paying attorneys' fees, entering into a corporate integrity agreement, being excluded from participation in government healthcare programs, including Medicare and Medicaid, and other adverse actions that could materially and adversely affect the Company's business, financial condition and results of operation. See Note 19 for additional information on the Company's fair value determination of this pre-acquisition loss contingency related to the Genomic Health DOJ investigation. In connection with the Company's combination with Genomic Health, on June 22, 2020, Suzanne Flannery, a purported former stockholder of Genomic Health, filed a Verified Individual and Class Action Complaint in the Delaware Court of Chancery, captioned Flannery v. Genomic Health, Inc., et al., C.A. No. 2020-0492. Flannery amended her complaint on November 23, 2020. The amended complaint asserts individual and class action claims, including: (i) a violation of 8 Del. C. § 203 by Genomic Health, Exact Sciences and a purported controlling group of former Genomic Health stockholders; (ii) conversion by Genomic Health, Exact Sciences and Spring Acquisition Corp.; (iii) breach of fiduciary duty by Genomic Health's former directors; (iv) breach of fiduciary duty by the purported controlling group; and (v) aiding and abetting breach of fiduciary duty against Exact Sciences, Spring Acquisition and Goldman Sachs & Co. LLC, Genomic Health's financial advisor in the combination. The amended complaint seeks, among other things, declaratory relief, unspecified monetary damages and attorneys' fees and costs. All defendants moved to dismiss the amended complaint. These investigations are still in process and the scope and outcome of the investigations is not determinable at this time. There can be no assurance that any settlement, resolution, or other outcome of these matters during any subsequent reporting period will not have a material adverse effect on the Company’s results of operations or cash flows for that period or on the Company’s financial position.

EMPLOYEE BENEFIT PLAN

EMPLOYEE BENEFIT PLAN	12 Months Ended
	Dec. 31, 2020
Retirement Benefits [Abstract]
EMPLOYEE BENEFIT PLAN	EMPLOYEE BENEFIT PLAN The Company maintains a qualified 401(k) retirement savings plan for Exact Sciences employees (the "401(k) Plan"). After the combination with Genomic Health in 2019, the Company maintained a plan for legacy Genomic Health employees (the "Genomic Health Plan") up until the Genomic Health Plan was merged into the 401(k) Plan effective April 3, 2020. Under the terms of the 401(k) Plan, participants may elect to defer a portion of their compensation into the 401(k) Plan, subject to certain limitations. Company matching contributions may be made at the discretion of the Board of Directors. The Company’s Board of Directors approved 401(k) Plan matching contributions for the years ended December 31, 2020, 2019 and 2018 in the form of Company common stock equal to 100 percent up to 6 percent of the participant’s eligible compensation for that year. The Company recorded compensation expense of approximately $22.8 million, $12.5 million, and $7.4 million, respectively, in the statements of operations for the years ended December 31, 2020, 2019 and 2018.

NEW MARKET TAX CREDIT

NEW MARKET TAX CREDIT	12 Months Ended
	Dec. 31, 2020
NEW MARKET TAX CREDIT
NEW MARKET TAX CREDIT	NEW MARKET TAX CREDIT During the fourth quarter of 2014, the Company received approximately $2.4 million in net proceeds from financing agreements related to working capital and capital improvements at one of its Madison, Wisconsin facilities. This financing arrangement was structured with an unrelated third-party financial institution (the “Investor”), an investment fund, and its majority owned community development entity in connection with the Company’s participation in transactions qualified under the federal New Markets Tax Credit (“NMTC”) program, pursuant to Section 45D of the Internal Revenue Code of 1986, as amended. The Company is required to be in compliance through December 2021 with various regulations and contractual provisions that apply to the NMTC arrangement. Noncompliance with applicable requirements could result in the Investor’s projected tax benefits not being realized and, therefore, require the Company to indemnify the Investor for any loss or recapture of NMTC related to the financing until such time as the recapture provisions have expired under the applicable statute of limitations. The Company does not anticipate any credit recapture will be required in connection with this financing arrangement. The Investor and its majority owned community development entity are considered Variable Interest Entities (“VIEs”) and the Company is the primary beneficiary of the VIEs. This conclusion was reached based on the following: • the ongoing activities of the VIEs—collecting and remitting interest and fees and NMTC compliance—were all considered in the initial design and are not expected to significantly affect performance throughout the life of the VIE; • contractual arrangements obligate the Company to comply with NMTC rules and regulations and provide various other guarantees to the Investor and community development entity; • the Investor lacks a material interest in the underlying economics of the project; and • the Company is obligated to absorb losses of the VIEs. Because the Company is the primary beneficiary of the VIEs, they have been included in the consolidated financial statements. There are no other assets, liabilities or transactions in these VIEs outside of the financing transactions executed as part of the NMTC arrangement.

WISCONSIN ECONOMIC DEVELOPMENT

WISCONSIN ECONOMIC DEVELOPMENT TAX CREDITS	12 Months Ended
	Dec. 31, 2020
WISCONSIN ECONOMIC DEVELOPMENT TAX CREDITS.
WISCONSIN ECONOMIC DEVELOPMENT TAX CREDITS	WISCONSIN ECONOMIC DEVELOPMENT TAX CREDITS During the first quarter of 2015, the Company entered into an agreement with the Wisconsin Economic Development Corporation (“WEDC”) to earn $9.0 million in refundable tax credits on the condition that the Company expends $26.3 million in capital investments and establishes and maintains 758 full-time positions over a seven-year period. The tax credits earned are first applied against the tax liability otherwise due, and if there is no such liability present, the claim for tax credits will be reimbursed in cash to the Company. The maximum amount of the refundable tax credit to be earned for each year is fixed, and the Company earns the credits by meeting certain capital investment and job creation thresholds over the seven-year period. Should the Company earn and receive the job creation tax credits but not maintain those full-time positions through the end of the agreement, the Company may be required to pay those credits back to the WEDC. The Company records the earned tax credits as job creation and capital investments occur. The amount of tax credits earned is recorded as a liability and amortized as a reduction of operating expenses over the expected period of benefit. The tax credits earned from capital investment are recognized as an offset to depreciation expense over the expected life of the acquired capital assets. The tax credits earned related to job creation are recognized as an offset to operational expenses over the life of the agreement, as the Company is required to maintain the minimum level of full-time positions through the seven-year period. As of December 31, 2020, the Company has earned all $9.0 million of the refundable tax credits and has received payment of $5.9 million from the WEDC. The unpaid portion is $3.1 million, of which $1.6 million is reported in prepaid expenses and other current assets and $1.5 million is reported in other long-term assets, reflecting when collection of the refundable tax credits is expected to occur. As of December 31, 2020, the corresponding liability, which reflected when the expected benefit of the tax credit amortization would reduce future operating expenses, has been fully amortized and has a balance of zero. During the years ended December 31, 2020, 2019 and 2018, the Company amortized $2.2 million, $2.4 million, and $2.2 million, respectively, of the tax credits earned as a reduction of operating expenses.

BUSINESS COMBINATIONS & ASSET A

BUSINESS COMBINATIONS & ASSET ACQUISITIONS	12 Months Ended
	Dec. 31, 2020
Business Combinations [Abstract]
BUSINESS COMBINATIONS AND ASSET ACQUISITIONS	BUSINESS COMBINATIONS AND ASSET ACQUISITIONS Business Combinations Paradigm Diagnostics, Inc. and Viomics, Inc. On March 3, 2020, the Company acquired all of the outstanding capital stock of Paradigm and Viomics, two related party companies of one another headquartered in Phoenix, Arizona, in transactions that are deemed to be a single business combination in accordance with ASC 805, Business Combinations, (“the Paradigm Acquisition”). Paradigm provides comprehensive genomic-based profiling tests that assist in the diagnosis and therapy recommendations for late-stage cancer. Viomics provides a platform for identification of biomarkers. The Company entered into this acquisition to enhance its product portfolio in cancer diagnostics and to enhance its capabilities for biomarker identification. The acquisition date fair value of the consideration to be transferred for Paradigm and Viomics was $40.4 million, which consists of $32.2 million payable in shares of the Company’s common stock and $8.2 million which was settled through a cash payment. Of the $32.2 million to be settled through the issuance of common stock, $28.8 million was issued as of December 31, 2020, and the remaining $3.4 million, which was withheld and may become payable as additional merger consideration, is included in other current liabilities in the consolidated balance sheet as of December 31, 2020. The purchase price was allocated to the underlying assets acquired and liabilities assumed based upon their estimated fair values as follows: (In thousands) Preliminary Allocation Measurement Period Preliminary Allocation Net operating assets $ 6,133 $ (760) $ 5,373 Goodwill 29,695 736 30,431 Developed technology 7,800 — 7,800 Net operating liabilities (3,123) (80) (3,203) Total purchase price $ 40,505 $ (104) $ 40,401 The measurement period adjustments primarily relate to accounts receivable valuation and working capital adjustments. The fair value of identifiable intangible assets has been determined using the income approach, which involves significant unobservable inputs (Level 3 inputs). These inputs include projected sales, margin, weighted average cost of capital and tax rate. Developed technology represents purchased technology that had reached technological feasibility and for which development had been completed as of the acquisition date. Fair value was determined using future discounted cash flows related to the projected income stream of the developed technology for a discrete projection period. Cash flows were discounted to their present value as of the closing date. Developed technology is amortized on a straight-line basis over its estimated useful life of 15 years. The calculation of the excess of the purchase price over the estimated fair value of the tangible net assets and intangible assets acquired was recorded to goodwill, which is primarily attributed to the assembled workforce, and expected synergies. The total goodwill related to this acquisition is not deductible for tax purposes. The Company agreed to issue to the previous investors in Viomics equity interests with an acquisition-date fair value of up to $8.4 million in Viomics, vesting over 4 years based on certain retention arrangements. Payment is contingent upon continued employment with the Company over the four year vesting period and is recognized as stock-based compensation expense in general and administrative expense in the consolidated statement of operations. The partial year results from the operations of Paradigm and Viomics are included in the Company’s consolidated financial statements and not disclosed separately due to immateriality. Pro forma disclosures have not been included due to immateriality. Genomic Health, Inc. On November 8, 2019, the Company acquired all of the outstanding capital stock of Genomic Health. Genomic Health, headquartered in Redwood City, California, provides genomic-based diagnostic tests that address both the overtreatment and optimal treatment of early and late stage cancer. The Company has included the financial results of Genomic Health in the consolidated financial statements from the date of the combination. The Company entered into this combination to create a leading global cancer diagnostics company and provide a robust platform for continued growth. This combination provides the Company with a commercial presence in more than 90 countries in which the combined company expects to continue to increase adoption of current tests, and to bring new innovative cancer tests to patients around the world. During 2019, the Company incurred $22.5 million of acquisition-related costs recorded in general and administrative expense. These costs include fees associated with financial, legal, accounting and other advisors incurred to complete the combination. The combination date fair value of the consideration transferred for Genomic Health was approximately $2.47 billion, which consisted of the following: (In thousands) Cash $ 1,061,489 Common stock issued 1,389,266 Fair value of replacement stock options and restricted stock awards 17,813 Total purchase price $ 2,468,568 The fair value of the common stock issued as part of consideration was determined on the basis of the closing market price of the Company's shares at the acquisition date. The fair value of the stock options assumed by the Company was determined using the Black-Scholes option pricing model. The share conversion ratio of 0.76534 was applied to convert Genomic Health’s outstanding equity awards for Genomic Health’s common stock into equity awards for shares of the Company’s common stock. Th e fair value of options assumed were based on the assumptions in the following table: Option Plan Shares Assumed Risk-free interest rates 0.88% - 2.90% Expected term (in years) 3.28 - 6.73 Expected volatility 63.54% - 69.09% Dividend yield 0% Weighted average fair value per share of options assumed $45.75 - $57.44 The purchase price was allocated to the underlying assets acquired and liabilities assumed based upon their estimated fair values as follows: (In thousands) Preliminary Allocation Measurement Period Final Allocation Cash and cash equivalents $ 87,627 $ — $ 87,627 Marketable securities 201,519 — 201,519 Accounts receivable 57,400 — 57,400 Inventory 3,535 — 3,535 Prepaid expenses and other current assets 8,360 — 8,360 Property, plant and equipment 69,905 (122) 69,783 Goodwill 1,185,918 4,044 1,189,962 Trade name 100,000 — 100,000 Supply agreement intangible 30,000 — 30,000 Developed technology 800,000 — 800,000 In-process research and development (IPR&D) 200,000 — 200,000 Operating lease right-of-use assets 80,790 — 80,790 Other long-term assets 14,972 (96) 14,876 Accounts payable, accrued liabilities and other current liabilities (88,995) 548 (88,447) Deferred tax liability (205,536) (4,374) (209,910) Operating lease liabilities, current portion (3,258) — (3,258) Operating lease liabilities, less current portion (71,270) — (71,270) Other long-term liabilities (2,399) — (2,399) Total fair value consideration $ 2,468,568 $ — $ 2,468,568 The measurement period adjustments primarily relate to the fair value of Genomic Health's pre-acquisition deferred tax liability due to finalization of certain income-tax related items. The fair value of identifiable intangible assets has been determined using the income approach, which involves significant unobservable inputs (Level 3 inputs). These inputs include projected sales, margin, required rate of return and tax rate, as well as an estimated royalty rate in the cases of the developed technology and trade name intangibles. The developed technology and tradename intangibles are valued using a relief-from-royalty method. Trade names represent the value associated with the Oncotype DX trade name in the market. The trade name intangible is amortized on a straight-line basis over its estimated useful life of 16 years. Developed technology represents purchased technology that had reached technological feasibility and for which Genomic Health had substantially completed development as of the date of combination. Fair value was determined using future discounted cash flows related to the projected income stream of the developed technology for a discrete projection period. Cash flows were discounted to their present value as of the closing date. Developed technology is amortized on a straight-line basis over its estimated useful life of 10 years. IPR&D represent capitalized incomplete research projects as of the combination date and had no alternative future use. The amounts capitalized are being accounted for as indefinite-lived intangible assets, subject to impairment testing, until completion or abandonment of the research and development efforts associated with the projects. The primary basis for determining technological feasibility of these projects is obtaining regulatory approval to market the underlying product and expected commercial release. The Company recorded $200.0 million of IPR&D related to the development of an IVD version of the Oncotype DX Breast Recurrence Score test. The IPR&D asset was valued using the multiple-period excess earnings method approach. The calculation of the excess of the purchase price over the estimated fair value of the tangible net assets and intangible assets acquired was recorded to goodwill, which is primarily attributed to the assembled workforce and expanded market opportunities including a broader global presence. The total goodwill related to this combination is not deductible for tax purposes. The Company assumed unvested stock options and restricted stock awards with combination-date fair values of $34.3 million and $42.3 million, respectively. Of the total consideration for stock options and restricted stock awards, $2.2 million and $15.6 million, respectively, was allocated to the purchase consideration and $32.1 million and $26.7 million, respectively, was allocated to future services and will be expensed over a weighted average period of 1.69 years and 2.12 years, respectively. The amounts of revenue and net loss before tax of Genomic Health included in the Company’s consolidated statement of operations from the combination date of November 8, 2019 to December 31, 2019 and for the year ended December 31, 2020 are as follows: (In thousands) 2020 2019 Total revenues $ 435,960 $ 66,174 Net loss before tax (254,162) (40,446) The following unaudited pro forma financial information summarized the combined results of operations for the Company and Genomic Health, as though the companies were combined as of the beginning of January 1, 2018. Year Ended December 31, (In thousands) 2019 2018 Total revenues $ 1,266,591 $ 848,573 Net loss before tax (252,203) (302,173) The unaudited pro forma financial information for all periods presented above has been calculated after adjusting the results of Genomic Health to reflect the business combination accounting effects resulting from this combination, including the amortization expense from acquired intangible assets and the stock-based compensation expense for unvested stock options and restricted stock awards assumed as though the combination occurred as of January 1, 2018. The historical consolidated financial statements have been adjusted in the unaudited pro forma combined financial information to give effect to pro forma events that are directly attributable to the business combination and factually supportable. The unaudited pro forma financial information is for informational purposes only and is not indicative of the results of operations that would have been achieved if the combination had taken place as of January 1, 2018. As described in Note 15, the Company identified a pre-acquisition contingency relating to the DOJ investigation. The Company assigned a fair value estimate of zero to this pre-acquisition contingency. Subsequent to the Company's final determination of the pre-acquisition contingency’s estimated value, changes to this estimate could have a material impact on our results of operations and financial position. In connection with the combination, the Company decided to terminate certain Genomic Health executives in the fourth quarter of 2019 and recorded $32.1 million in severance benefits charges. Asset Acquisitions Base Genomics, Limited On October 26, 2020, The Company acquired all of the outstanding capital stock of Base Genomics, Limited in a cash transaction totaling $416.5 million. Base Genomics headquartered in Oxford, England exclusively licenses from Ludwig a non-bisulfite technology for the detection of methylated DNA and other epigenetic modifications. This technology (“TAPS”) simultaneously generates both genetic and epigenetic information at base resolution. TAPS overcomes the issues of the current gold-standard for DNA methylation detection of bisulfite sequencing. The Company has included the financial results of Base Genomics in the consolidated statements from the date of the acquisition and not disclosed separately due to immateriality. Pro forma disclosures have not been included due to immateriality. While the acquisition was treated legally as a merger of the two entities, for accounting purposes, the transaction was treated as an asset acquisition under GAAP because substantially all of the fair value of the gross assets acquired were deemed to be associated with the TAPS technology. The assets and liabilities acquired in the merger were recorded at fair value as determined as of October 26, 2020, and were substantially comprised of the TAPS IPR&D asset as shown in the table below. The Company incurred approximately $4.6 million of direct transaction costs during 2020 associated with this acquisition. These acquisition-related transaction costs were capitalized to the acquired tangible and intangible assets based on their estimated fair values as of the closing date. The IPR&D asset acquired was recorded to research and development expense in the consolidated statement of operations immediately after acquisition as the asset was deemed to be incomplete and had no alternative future use at the time of acquisition. The Company accounted for the merger in accordance with the accounting standards codification guidance for business combinations, whereby the total purchase price was allocated to the acquired net tangible and intangible assets based on their estimated fair values as of the closing date. As of December 31, 2020, the Company has substantially completed its process for measuring the fair values of the assets acquired and liabilities assumed based on information available as of the closing date. The following table summarizes the total consideration for the acquisition and the value of assets acquired and liabilities assumed as of October 26, 2020, the Merger closing date. These values are based on internal Company and independent external third-party valuations: (In thousands) Consideration Cash paid for acquisition of Base Genomics outstanding shares $ 416,525 Transaction costs 4,600 Total consideration 421,125 Assets acquired and liabilities assumed Cash 9,704 IPR&D asset 412,568 Other assets and liabilities (1,147) Net assets acquired $ 421,125

SEGMENT INFORMATION

SEGMENT INFORMATION	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
SEGMENT INFORMATION	SEGMENT INFORMATIONManagement determined that the Company functions as a single operating segment, and thus reports as a single reportable segment. This operating segment is focused on the development and global commercialization of clinical laboratory services allowing healthcare providers and patients to make individualized treatment decisions. Management assessed the discrete financial information routinely reviewed by the Company's Chief Operating Decision Maker, its President and Chief Executive Officer, to monitor the Company's operating performance and support decisions regarding allocation of resources to its operations. Performance is continuously monitored at the consolidated level to timely identify deviations from expected results. The following table summarizes total revenue from customers by geographic region. Product revenues are attributed to countries based on ship-to location. Year Ended December 31, (In thousands) 2020 2019 2018 United States $ 1,413,907 $ 864,849 $ 454,462 Outside of United States 77,484 11,444 — Total revenues $ 1,491,391 $ 876,293 $ 454,462 Long-lived assets located in countries outside of the United States are not significant.

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES Under financial accounting standards, deferred tax assets or liabilities are computed based on the differences between the financial statement and income tax bases of assets and liabilities using the enacted tax rates. Deferred income tax expense or benefit represents the change in the deferred tax assets or liabilities from period to period. At December 31, 2020, the Company had federal net operating loss, state net operating loss, and foreign net operating loss carryforwards of approximately $1.55 billion, $709.2 million, and $4.3 million, respectively for financial reporting purposes, which may be used to offset future taxable income. The Company also had federal and state research tax credit carryforwards of $54.3 million and $34.0 million, respectively which may be used to offset future income tax liability. The federal credit carryforwards expire at various dates through 2040 and are subject to review and possible adjustment by the Internal Revenue Service. The state credit carryforwards expire at various dates through 2035 with the exception of California research and development tax credits that have an indefinite carryforward period. All state tax credits are subject to review and possible adjustment by local tax jurisdictions. In the event of a change of ownership, the federal and state net operating loss and research and development tax credit carryforwards may be subject to annual limitations provided by the Internal Revenue Code and similar state provisions. Income (loss) before provision for taxes consisted of the following: Year Ended December 31, (In thousands) 2020 2019 2018 Income (loss) before income taxes: Domestic $ (451,067) $ (267,832) $ (175,275) Foreign (406,038) (1,019) 218 Total income (loss) before income taxes $ (857,105) $ (268,851) $ (175,057) The expense (benefit) for income taxes consists of: Year Ended December 31, (In thousands) 2020 2019 2018 Current expense (benefit): Federal $ (3) $ — $ — State 802 314 92 Foreign 933 (63) — Deferred tax expense (benefit): Federal (6,453) (169,727) — State (3,971) (15,397) — Foreign 120 15 — Total income tax expense (benefit) $ (8,572) $ (184,858) $ 92 The Company recorded an income tax benefit for the year ended December 31, 2020 of $8.6 million primarily as a result of future limitations on and expiration of certain Federal and State deferred tax assets. The components of the net deferred tax asset with the approximate income tax effect of each type of carryforward, credit and temporary differences are as follows: December 31, (In thousands) 2020 2019 Deferred tax assets: Operating loss carryforwards $ 369,642 $ 369,695 Tax credit carryforwards 64,760 51,030 Compensation related differences 48,349 33,378 Lease assets 31,938 30,782 Other temporary differences 6,136 7,049 Tax assets before valuation allowance 520,825 491,934 Less - Valuation allowance (157,629) (120,679) Total deferred tax assets $ 363,196 $ 371,255 Deferred tax liabilities Convertible notes $ (145,925) $ (83,163) Amortization (197,847) (270,421) Property, plant and equipment (4,580) (5,913) Lease liabilities (30,312) (29,586) Other temporary differences (4,078) (2,607) Total deferred tax liabilities (382,742) (391,690) Net deferred tax liabilities $ (19,546) $ (20,435) A valuation allowance to reduce the deferred tax assets is reported if, based on the weight of the evidence, it is more likely than not that some portion or all of the deferred tax assets will not be realized. The Company has incurred significant losses since its inception and due to the uncertainty of the amount and timing of future taxable income and the realization of deferred tax liabilities, management has determined that a valuation allowance of $157.6 million and $120.7 million at December 31, 2020 and 2019, respectively, is necessary to reduce the tax assets to the amount that is more likely than not to be realized. Given the future limitations on and expiration of certain federal and state deferred tax assets, the recording of a valuation allowance resulted in a deferred tax liability of approximately $19.5 million remaining at the end of 2020, which is included in other long-term liabilities on the Company's consolidated balance sheet. The overall change in valuation allowance for December 31, 2020 and 2019 was an increase of $36.9 million and a decrease of $89.2 million, respectively. Activity associated with the Company's valuation allowance is as follows: December 31, (In thousands) 2020 2019 2018 Balance as of January 1, $ (120,679) $ (209,868) $ (214,250) Valuation allowances established (108,944) (132,522) (52,855) Changes to existing valuation allowances 1,662 1,620 (2,744) Acquisition and purchase accounting (5,558) 183,730 (1,739) Additional paid-in-capital 75,890 36,361 61,720 Balance as of December 31, $ (157,629) $ (120,679) $ (209,868) During 2020, the Company recorded an increase to the valuation allowance of $108.9 million primarily related to losses from continuing operations. Additionally, the Company recorded a decrease to the valuation allowance of $75.9 million related to convertible debt issuances offset against additional paid-in capital. During 2019, the Company recorded an increase to the valuation allowance of $132.5 million primarily related to losses from continuing operations. Additionally, the Company recorded a decrease to the valuation allowance of $183.7 million related to the Genomic Health combination offset against goodwill, as well as a decrease of $36.4 million related to convertible debt issuances offset against additional paid-in capital. During 2018, the Company recorded an increase to the valuation allowance of $52.9 million primarily related to losses from continuing operations. Additionally, the Company recorded a decrease to the valuation allowance of $61.7 million related to convertible debt issuances offset against additional paid-in capital. The effective tax rate differs from the statutory tax rate due to the following: December 31, 2020 2019 2018 U.S. Federal statutory rate 21.0 % 21.0 % 21.0 % State taxes 1.9 5.8 3.4 Federal and state tax rate changes — (0.4) — Foreign tax rate differential (1.0) 0.6 — Acquired IPR&D asset expense (9.1) — — Research and development tax credits 1.6 1.1 1.9 Stock-based compensation expense 1.1 22.1 9.1 Non-deductible executive compensation (0.8) (4.1) (4.9) Transaction costs (0.1) (0.7) — Other adjustments (1.0) (0.6) 1.1 Valuation allowance (12.7) 24.0 (31.7) Effective tax rate 0.9 % 68.8 % (0.1) % For the year ended December 31, 2020, the Company recognized an income tax benefit, representing an effective tax rate of 0.9%. The difference between the expected statutory federal tax rate of 21.0% and the effective tax rate of 0.9% for the year ended December 31, 2020, was primarily attributable to the valuation allowance established against the Company's current period losses generated and the non-deductible IPR&D expense related to the Base Genomics acquisition. For the year ended December 31, 2019, the Company recognized an income tax benefit, representing an effective tax rate of 68.8%. The difference between the expected statutory federal tax rate of 21.0% and the effective tax rate of 68.8% for the year ended December 31, 2019, was primarily attributable to an income tax benefit of $185.1 million recorded as a result of a change in the deferred tax asset valuation allowance resulting from the Genomic Health combination, as well as excess tax benefits on vested stock-based compensation awards. For the year ended December 31, 2018, the Company recognized an immaterial income tax expense, representing an effective tax rate of (0.1)%. The difference between the expected statutory federal tax rate of 21.0% and the effective tax rate of (0.1)% for the year ended December 31, 2018, was primarily attributable to the valuation allowance established against our current period losses generated. The Company had unrecognized tax benefits related to federal and state research and development tax credits of $16.6 million, $10.3 million, and $1.9 million as of December 31, 2020, 2019 and 2018, respectively. These amounts have been recorded as a reduction to our deferred tax asset, if recognized they would not have an impact on the effective tax rate due to the existing valuation allowance. Certain of the Company's unrecognized tax benefits could change due to activities of various tax authorities, including possible settlement of audits, or through normal expiration of various statutes of limitations. The Company does not expect a material change in unrecognized tax benefits in the next twelve months. The following is a tabular reconciliation of the amounts of unrecognized tax benefits: December 31, (In thousands) 2020 2019 2018 January 1, $ 10,276 $ 1,926 $ — Increase due to current year tax positions 3,600 2,142 392 Increase due to prior year tax positions 2,753 6,208 1,534 Decrease due to prior year tax positions — — — Settlements — — — December 31, $ 16,629 $ 10,276 $ 1,926 As of December 31, 2020, due to the carryforward of unutilized net operating losses and research and development credits, the Company is subject to U.S. federal income tax examinations for the tax years 2001 through 2020, and to state income tax examinations for the tax years 2001 through 2020. There were no interest or penalties related to income taxes that have been accrued or recognized as of and for the years ended December 31, 2020, 2019 and 2018.

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	12 Months Ended
	Dec. 31, 2020
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	SUBSEQUENT EVENTS On January 5, 2021, the Company completed the acquisition ("Thrive Merger") of Thrive Earlier Detection Corporation, pursuant to a merger through which the Company acquired all of the outstanding shares of Thrive. Thrive is a healthcare company dedicated to incorporating earlier cancer detection into routine medical care. The Company expects that combining Thrive’s early-stage screening test, CancerSEEK, with the Company’s scientific platform, clinical organization and commercial infrastructure will establish the Company as a leading competitor in blood-based, multi-cancer screening. Under the terms of the Thrive Merger, we paid Thrive's stockholders total consideration of $1.70 billion at closing, comprised of 35% in cash and 65% in the Company’s common stock. An additional $450.0 million would be payable in cash based upon the achievement of certain milestones related to the development and commercialization of a blood-based, multi-cancer screening test. Due to the proximity of the completion of the acquisition to the filing of this Form 10-K, the accounting for the preliminary purchase price allocation is not complete, including the valuation of total consideration paid, assets acquired and liabilities assumed. Through the Thrive Merger, the Company acquired a worldwide exclusive license agreement with John Hopkins University (“JHU”) for use of several JHU patents and licensed know-how. The license is designed to enable the Company to leverage JHU proprietary data in the development and commercialization of a blood-based, multi-cancer screening test. The agreement terms include single-digit sales-based royalties and sales-based milestone payments of $10.0 million, $15.0 million, $20.0 million and upon achieving calendar year licensed product revenue using JHU proprietary data of $0.50 billion, $1.00 billion, and $1.50 billion, respectively. On January 11, 2021, the Company acquired a worldwide exclusive license to the proprietary Targeted Digital Sequencing (“TARDIS”) technology from the Translational Genomics Research Institute (“TGen”), an affiliate of City of Hope for an up-front cost of $25.0 million in cash and issuance of 191,336 shares of common stock valued at $27.3 million on the date of issuance. This license is a royalty-free, perpetual license. Under the terms of the agreement, the Company is required to pay cash of $10.0 million and $35.0 million upon achieving cumulative product revenue related to minimal residual disease (“MRD”) detection and/or treatment totaling $100.0 million and $250.0 million, respectively. These payments are contingent upon achievement of these cumulative revenues on or before December 31, 2030. On February 12, 2021, the Company entered into an Equity Purchase Agreement (the “Ashion Purchase Agreement”) with PMed Management, LLC (“PMed”) which is a subsidiary of TGen pursuant to which the Company will purchase all of the outstanding equity interests of Ashion Analytics, LLC (“Ashion”; such transaction, the "Ashion Acquisition") in exchange for cash of approximately $72.0 million and 125,444 shares of the Company’s common stock. An additional $20.0 million and $30.0 million would be payable in cash upon the development and commercialization of a test for MRD detection and/or treatment (the “Commercial Launch Milestone”) and cumulative revenues from MRD products of $500.0 million (the “MRD Product Revenue Milestone”), respectively. The Commercial Launch Milestone is contingent upon achievement on or before the fifth anniversary of the closing and the MRD Product Revenue Milestone is contingent upon achievement on or before the tenth anniversary of the closing. Ashion is a CLIA-certified and CAP-accredited sequencing lab based in Phoenix, Arizona. Ashion developed GEMExTra®, one of the most comprehensive genomic cancer tests available, and provides access to whole exome, matched germline, and transcriptome sequencing capabilities. The Company currently expects the Ashion Acquisition to close during the second quarter of 2021, subject to customary closing conditions.

QUARTERLY RESULTS OF OPERATIONS

QUARTERLY RESULTS OF OPERATIONS (UNAUDITED)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
QUARTERLY RESULTS OF OPERATIONS (UNAUDITED)	QUARTERLY RESULTS OF OPERATIONS (UNAUDITED) The following table sets forth unaudited quarterly statements of operations data for each of the eight quarters ended December 31, 2020 and 2019. In the opinion of management, this information has been prepared on the same basis as the audited consolidated financial statements and contains all adjustments, consisting only of normal recurring adjustments, considered necessary for a fair statement of the unaudited quarterly results for the periods presented. The quarterly data should be read in conjunction with the Company’s audited consolidated financial statements and the notes to the consolidated financial statements appearing elsewhere in this Form 10-K. Quarter Ended (3) March 31, June 30, September 30, December 31, (Amounts in thousands, except per share data) 2020 Revenue $ 347,821 $ 268,868 $ 408,363 $ 466,339 Cost of sales (exclusive of amortization of acquired intangible assets) 81,606 77,892 95,061 99,765 Amortization of acquired intangible assets (1) 20,464 20,555 20,555 20,553 Gross profit 245,751 170,421 292,747 346,021 Operating expenses, net (2) 328,124 237,430 496,082 761,323 Interest income and interest expense (25,056) (20,000) (21,059) (22,971) Income tax benefit 1,732 867 4,510 1,463 Net loss $ (105,697) $ (86,142) $ (219,884) $ (436,810) Net loss per share—basic $ (0.71) $ (0.58) $ (1.46) $ (2.79) Net loss per share—diluted $ (0.71) $ (0.58) $ (1.46) $ (2.79) Weighted average common shares outstanding—basic 148,151 149,727 150,155 156,470 Weighted average common shares outstanding—diluted 148,151 149,727 150,155 156,470 2019 Revenue $ 162,043 $ 199,870 $ 218,805 $ 295,575 Cost of sales (exclusive of amortization of acquired intangible assets) 42,827 51,139 52,335 70,416 Amortization of acquired intangible assets (1) 425 424 424 11,981 Gross profit 118,791 148,307 166,046 213,178 Operating expenses (2) 186,865 182,209 201,772 309,258 Interest income and interest expense (15,335) (5,043) (4,116) (10,575) Income tax benefit (expense) 470 443 (683) 184,628 Net income (loss) $ (82,939) $ (38,502) $ (40,525) $ 77,973 Net income (loss) per share—basic $ (0.66) $ (0.30) $ (0.31) $ 0.56 Net income (loss) per share—diluted $ (0.66) $ (0.30) $ (0.31) $ 0.54 Weighted average common shares outstanding—basic 126,248 129,182 129,567 139,901 Weighted average common shares outstanding—diluted 126,248 129,182 129,567 143,200 _________________________________ (1) Includes only amortization of acquired intangible assets identified as developed technology assets through purchase accounting transactions, which otherwise would have been allocated to cost of sales. (2) Consists of research and development, sales and marketing, general and administrative, and amortization of acquired intangible assets excluding acquired developed technology, which is included in the gross profit calculation above. This also includes intangible asset impairment charges and funding received as part of the CARES Act. Refer to Note 6 for further discussion on the intangible asset impairment charges recorded in the third quarter of 2020. Refer to Note 1 for further discussion on the funding received as part of the CARES Act in the second quarter of 2020.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Business	Business Exact Sciences Corporation (together with its subsidiaries, “Exact,” or the “Company”) was incorporated in February 1995. Exact is a leading global cancer screening and diagnostics company. It has developed some of the most impactful brands in cancer screening and diagnostics, including Cologuard ® and Oncotype DX ®
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation The accompanying consolidated financial statements include the accounts of Exact Sciences Corporation and those of its wholly-owned subsidiaries and variable interest entities. All intercompany transactions and balances have been eliminated upon consolidation.
Use of Estimates	Use of Estimates The preparation of the consolidated financial statements in conformity with accounting principles generally accepted in the United States ("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. Critical accounting policies are those that affect the Company's financial statements materially and involve difficult, subjective or complex judgments by management, and actual results could differ from those estimates. These estimates include revenue recognition, valuation of convertible notes, valuation of intangible assets and goodwill, and accounting for income taxes among others. The spread of the coronavirus (“COVID-19”) has affected many segments of the global economy, including the cancer screening and diagnostics industry. The COVID-19 outbreak, which the World Health Organization has classified as a pandemic, has prompted governments and regulatory bodies throughout the world to enact broad precautionary measures, including “stay-at-home” orders, restrictions on the performance of “non-essential” services, public gatherings and travel. Health systems, including key markets where the Company operates, have been, or may be, overwhelmed with high volumes of patients suffering from COVID-19. Even in areas where “stay-at-home” restrictions have been lifted and the number of cases of COVID-19 has declined, many individuals remain cautious about resuming activities such as preventive-care medical visits. Medical practices continue to be cautious about allowing individuals, such as sales representatives, into their offices. Many individuals continue to work from home rather from an office setting. The Company cannot forecast when the COVID-19 pandemic will end or the extent to which practices that have emerged during the pandemic will continue once it subsides. The extent to which COVID-19 impacts the Company’s business and financial results will depend on numerous evolving factors including, but not limited to: the magnitude and duration of COVID-19, the extent to which it will impact worldwide macroeconomic conditions including interest rates, employment rates and health insurance coverage, the speed of the anticipated recovery, access to capital markets, and governmental and business reactions to the pandemic. The Company assessed certain accounting matters that generally require consideration of forecasted financial information in context with the information reasonably available to the Company and the unknown future impacts of COVID-19 as of December 31, 2020 and through the date of the filing of this Annual Report on Form 10-K. The accounting matters assessed included, but were not limited to, the Company’s allowance for doubtful accounts and credit losses, equity investments, software, and the carrying value of the goodwill and other long-lived assets. The Company’s future assessment of the magnitude and duration of COVID-19, as well as other factors, could result in additional material impacts to the Company’s consolidated financial statements in future reporting periods. The pandemic and related precautionary measures began to materially disrupt the Company's operations in March 2020 and may continue to disrupt the business for an unknown period of time. As a result, the pandemic had a significant impact on the Company's 2020 revenues and operating results. The ultimate impact of COVID-19 depends on factors beyond the Company’s knowledge or control, including the duration and severity of the outbreak, as well as third-party actions taken to contain its spread and mitigate its public health effects. As a result, the Company is unable to estimate the extent to which COVID-19 will negatively impact its financial results or liquidity. Coronavirus Aid, Relief, and Economic Security Act (“CARES Act”) In April 2020, the Company received $23.7 million from the United States Department of Health and Human Services (“HHS”) as a distribution from the Public Health and Social Services Emergency Fund provided for in the CARES Act. The fund payments are grants, not loans, and HHS will not require repayment provided the funds are utilized to offset expenses incurred to address COVID-19 or to replace lost revenues. The Company accepted the terms and conditions of the grant in May 2020 and recognized the entire $23.7 million during the year ended December 31, 2020, due to lost revenue attributable to COVID-19, which is reflected in other operating income in the consolidated statement of operations. The Company cannot predict the extent to which it might receive any additional funds to be paid out under the Provider Relief Fund, and to what extent the financial impact of receiving such funds might offset the broad implications of the COVID-19 pandemic, which include increases in the Company’s costs and lost revenues.
Cash and Cash Equivalents	Cash and Cash EquivalentsThe Company considers cash on hand, demand deposits in a bank, money market funds, and all highly liquid investments with an original maturity of 90 days or less to be cash and cash equivalents.
Marketable Securities	Marketable Securities Management determines the appropriate classification of debt securities at the time of purchase and re-evaluates such designation as of each balance sheet date. Debt securities carried at amortized cost are classified as held-to-maturity when the Company has the positive intent and ability to hold the securities to maturity. Debt securities not classified as held-to-maturity are classified as available-for-sale. Available-for-sale securities are carried at fair value. The unrealized gains and losses, net of tax, on the Company's debt securities are reported in other comprehensive income. Marketable equity securities are measured at fair value and the unrealized gains and losses, net of tax, are recognized in other income (expense) in the consolidated statements of operations. The amortized cost of debt securities in this category is adjusted for amortization of premiums and accretion of discounts to maturity computed under the effective interest rate method. Such amortization is included in investment income, net. Realized gains and losses and declines in value as a result of credit losses on available-for-sale securities are included in the consolidated statements of operations as investment income, net. The cost of securities sold is based on the specific identification method. Interest and dividends on securities classified as available-for-sale are included in the consolidated statements of operations as investment income, net. The Company’s investment policy limits investments to certain types of instruments issued by institutions with investment grade credit ratings and places restrictions on maturities and concentration by type and issuer. Investments in which the Company has the ability and intent, if necessary, to liquidate in order to support its current operations (including those with a contractual term greater than one year from the date of purchase) are classified as current.
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts The Company estimates an allowance for doubtful accounts against accounts receivable using historical collection trends, aging of accounts, current and future implications surrounding the ability to collect such as economic conditions, and regulatory changes. The allowance for doubtful accounts is evaluated on a regular basis and adjusted when trends, significant events or other substantive evidence indicate that expected collections will be less than applicable accrual rates. At December 31, 2020 and 2019, the allowance for doubtful accounts recorded was not material to the Company's consolidated balance sheets. For the years ended December 31, 2020, 2019 and 2018, there was an immaterial amount of bad debt expense written off against the allowance and charged to operating expense.
Inventory	Inventory Inventory is stated at the lower of cost or net realizable value. The Company determines the cost of inventory using the first-in, first out method (“FIFO”). The Company estimates the recoverability of inventory by reference to internal estimates of future demands and product life cycles, including expiration. The Company periodically analyzes its inventory levels to identify inventory that may expire prior to expected sale, no longer meet quality specifications, or has a cost basis in excess of its estimated realizable value and records a charge to cost of sales for such inventory as appropriate. Direct and indirect manufacturing costs incurred during process validation with probable future economic benefit are capitalized. Validation costs incurred for other research and development activities, which are not permitted to be sold, have been expensed to research and development in the Company’s consolidated statements of operations.
Property, Plant and Equipment	Property, Plant and EquipmentProperty, plant and equipment are stated at cost and depreciated using the straight-line method over the assets’ estimated useful lives. Land is stated at cost and does not depreciate. Additions and improvements are capitalized, including direct and indirect costs incurred to validate equipment and bring to working conditions. Revalidation costs, including maintenance and repairs are expensed when incurred.
Software Development Costs	Software Development Costs Costs related to internal use software, including hosted arrangements, are incurred in three stages: the preliminary project stage, the application development stage, and the post-implementation stage. Costs incurred during the preliminary project and post-implementation stages are expensed as incurred. Costs incurred during the application development stage that meet the criteria for capitalization are capitalized and amortized, when the software is ready for its intended use, using the straight‑line basis over the estimated useful life of the software, or the duration of the hosting agreement.
Investments in Privately Held Companies	Investments in Privately Held Companies The Company determines whether its investments in privately held companies are debt or equity based on their characteristics, in accordance with the applicable accounting guidance for such investments. The Company also evaluates the investee to determine if the entity is a variable interest entity (“VIE”) and, if so, whether the Company is the primary beneficiary of the VIE, in order to determine whether consolidation of the VIE is required. If consolidation is not required and the Company does not have voting control of the entity, the investment is evaluated to determine if the equity method of accounting should be applied. The equity method applies to investments in common stock or in substance common stock where the Company exercises significant influence over the investee. Investments in privately held companies determined to be equity securities are accounted for as non-marketable securities. The Company adjusts the carrying value of its non-marketable equity securities for changes from observable transactions for identical or similar investments of the same issuer, less impairment. All gains and losses on non-marketable equity securities, realized and unrealized, are recognized in investment income, net in the consolidated statements of operations. Investments in privately held companies determined to be debt securities are accounted for as available-for-sale or held to maturity securities, in accordance with the applicable accounting guidance for such investments.
Derivative Financial Instruments	Derivative Financial InstrumentsThe Company hedges a portion of its foreign currency exposures related to outstanding monetary assets and liabilities using foreign currency forward contracts. The foreign currency forward contracts are included in prepaid expenses and other current assets or in accrued liabilities in the consolidated balance sheets, depending on the contracts’ net position. These contracts are not designated as hedges, and as a result, changes in their fair value are recorded in other income (expense) in the consolidated statements of operations.
Business Combinations and Asset Acquisitions	Business Combinations and Asset AcquisitionsBusiness Combinations are accounted for under the acquisition method in accordance with Accounting Standards Codification ("ASC") 805, Business Combinations. The acquisition method requires identifiable assets acquired and liabilities assumed and any non-controlling interest in the business acquired be recognized and measured at fair value on the acquisition date, which is the date that the acquirer obtains control of the acquired business. The amount by which the fair value of consideration transferred as the purchase price exceeds the net fair value of assets acquired and liabilities assumed is recorded as goodwill. Acquisitions that do not meet the definition of a business combination under the ASC are accounted for as asset acquisitions. Asset acquisitions are accounted for by allocating the cost of the acquisition to the individual assets acquired and liabilities assumed on a relative fair value basis. Goodwill is not recognized in an asset acquisition with any consideration in excess of net assets acquired allocated to acquired assets on a relative fair value basis. Transaction costs are expensed in a business combination and are considered a component of the cost of the acquisition in an asset acquisition.
Intangible Assets	Intangible Assets Purchased intangible assets are recorded at fair value. The Company uses a discounted cash flow model to value intangible assets. The discounted cash flow model requires assumptions about the timing and amount of future net cash flows, risk, the cost of capital, terminal values and market participants. Patent costs are capitalized as incurred, only if the Company determines that there is some probable future economic benefit derived from the transaction. A capitalized patent is amortized over its estimated useful life, beginning when such patent is approved. Capitalized patent costs are expensed upon disapproval, upon a decision by the Company to no longer pursue the patent or when the related intellectual property is either sold or deemed to be no longer of value to the Company. The Company determined that all patent costs incurred during the years ended December 31, 2020, 2019 and 2018 should be expensed and not capitalized as the future economic benefit derived from the patent costs incurred cannot be determined.
Acquired In-process Research and Development (IPR&D)	Acquired In-process Research and Development ("IPR&D") Acquired IPR&D represents the fair value assigned to research and development assets that have not reached technological feasibility. The value assigned to acquired IPR&D is determined by estimating the costs to develop the acquired technology into commercially viable products, estimating the resulting revenues from the projects and discounting the net cash flows to present value. The revenues and cost projections used to value acquired IPR&D are, as applicable, reduced based on the probability of success. IPR&D projects acquired in a business combination that are not complete are capitalized and accounted for as indefinite-lived intangible assets until completion or abandonment of the related R&D efforts. Upon successful completion of the project, the capitalized amount is amortized over its estimated useful life. If a project is abandoned, all remaining capitalized amounts are written off immediately. There are often major risks and uncertainties associated with IPR&D projects as we are required to obtain regulatory approvals in order to be able to market the resulting products. Such approvals require completing clinical trials that demonstrate the products effectiveness. Consequently, the eventual realized value of the IPR&D project may vary from its fair value at the date of acquisition, and IPR&D impairment charges may occur in future periods.
Goodwill	GoodwillThe Company evaluates goodwill for possible impairment in accordance with Financial Accounting Standards Board ("FASB") ASC 350 on an annual basis during the fourth quarter, or more frequently if events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. Qualitative factors considered in this assessment include industry and market conditions, overall financial performance, and other relevant events and factors affecting the Company's business. Based on the qualitative assessment, if it is determined that the fair value of goodwill is more likely than not to be less than its carrying amount, the fair value of a reporting unit will be calculated and compared with its carrying amount and an impairment charge will be recognized for the amount that the carrying value exceeds the fair value.
Impairment of Long-Lived Assets	Impairment of Long-Lived AssetsThe Company evaluates the fair value of long-lived assets, which include property, plant and equipment, finite-lived intangible assets, and investments in privately held companies, for impairment whenever events or changes in circumstances indicate that the carrying amounts of the assets may not be fully recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to future undiscounted net cash flows expected to be generated by the asset. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds the fair value of the assets. Assets to be disposed of are reported at the lower of the carrying amount or fair value less costs to sell.
Net Loss Per Share	Net Loss Per Share Basic net loss per common share was determined by dividing net loss applicable to common stockholders by the weighted average common shares outstanding during the period. Basic and diluted net loss per share is the same because all outstanding common stock equivalents have been excluded, as they are anti-dilutive as a result of the Company’s losses.
Accounting for Stock-Based Compensation	Accounting for Stock-Based Compensation The Company requires all share-based payments to employees, including grants of employee stock options, restricted stock, restricted stock units, shares purchased under an employee stock purchase plan (if certain parameters are not met), and performance share units to be recognized in the financial statements based on their grant date fair values. Forfeitures of any share-based awards are recognized as they occur. The fair values and recognition of the Company's share-based payment awards are determined as follows: The fair value of each service-based option award is estimated on the date of grant using the Black-Scholes option-pricing model. The Black-Scholes pricing model utilizes the following assumptions: Expected Term —Expected life of an option award is the average length of time over which the Company expects employees will exercise their options, which is based on historical experience with similar grants. Expected Volatility —Expected volatility is based on the Company’s historical stock volatility data over the expected term of the awards. Risk-Free Interest Rate —The Company bases the risk-free interest rate on the implied yield currently available on U.S. Treasury zero-coupon issues with an equivalent expected term. The estimated fair value of these awards is recognized to expense using the straight-line method over the expected term.
Research and Development Costs	Research and Development Costs Research and development costs are expensed as incurred. These expenses include the costs of our proprietary research and development efforts, as well as costs of IPR&D projects acquired as part of an asset acquisition that have no alternative future use. Upfront and milestone payments due to third parties in connection with research and development collaborations prior to regulatory approval are expensed as incurred. Milestone payments due to third parties upon, or subsequent to, regulatory approval are capitalized and amortized into research and development costs over the shorter of the remaining license or product patent life, when there are no corresponding revenues related to the license or product. Nonrefundable advance payments for goods and services that will be used in future research and development activities are expensed when the activity has been performed or when the goods have been received, rather than when the payment is made. The Company incurred research and development expenses of $554.1 million, $139.7 million, and $67.3 million during the years ended December 31, 2020, 2019, and 2018, respectively, including IPR&D of $412.6 million that was acquired in an asset acquisition in 2020 and had no alternative future use. The value of the acquired IPR&D that was expensed was determined by identifying those acquired specific IPR&D projects that would be continued and which (a) were incomplete and (b) had no alternative future use. Acquired IPR&D assets that are acquired in an asset acquisition and which have no alternative future use are classified as an investing cash outflow in the consolidated statement of cash flows.
Advertising Costs	Advertising Costs The Company expenses the costs of media advertising at the time the advertising takes place. The Company expensed approximately $93.2 million, $88.7 million, and $93.7 million of media advertising during the years ended December 31, 2020, 2019, and 2018, respectively, which is recorded in sales and marketing expenses on the Company's consolidated statements of operations.
Fair Value Measurements	Fair Value Measurements The FASB has issued authoritative guidance that requires fair value to be based on the assumptions market participants would use when pricing an asset or liability and establishes a fair value hierarchy that prioritizes the information used to develop those assumptions. Under that standard, fair value measurements are separately disclosed by level within the fair value hierarchy. The fair value hierarchy establishes and prioritizes the inputs used to measure fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs. Observable inputs are inputs that reflect the assumptions that market participants would use in pricing the asset or liability developed based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the assumptions market participants would use in pricing the asset or liability developed based on the best information available in the circumstances.
Convertible Notes	Convertible Notes The Company accounts for convertible debt instruments that may be settled in cash or equity upon conversion by separating the liability and equity components of the instruments in a manner that reflects the Company’s nonconvertible debt borrowing rate. The Company determines the carrying amount of the liability component of the convertible debt instrument by using assumptions that market participants would use in pricing a debt instrument, including market interest rates, credit standing, yield curves, volatilities, and expected life of the instrument. Determining the fair value of the debt component requires the use of accounting estimates and assumptions. These estimates and assumptions are judgmental in nature and could have a significant impact on the determination of the debt component, and the associated non-cash interest expense.
Leases	Leases The Company acts as lessee in its lease agreements, which include operating leases for corporate offices, laboratory space, warehouse space, vehicles and certain laboratory and office equipment, and finance leases for certain equipment and vehicles. The Company determines whether an arrangement is, or contains, a lease at inception. At the beginning of fiscal year 2019, the company adopted ASC Topic 842. The Company records the present value of lease payments as right-of-use (“ROU”) assets and lease liabilities on the consolidated balance sheets. ROU assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent an obligation to make lease payments based on the present value of lease payments over the lease term. Classification of lease liabilities as either current or non-current is based on the expected timing of payments due under the Company’s obligations. As most of the Company’s leases do not provide an implicit interest rate, the Company uses its incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. The incremental borrowing rate is the rate of interest that a lessee would have to pay to borrow on a collateralized basis over a similar term and at an amount equal to the lease payments in a similar economic environment. In order to determine the appropriate incremental borrowing rates, the Company has used a number of factors including the credit rating, and the lease term. The ROU asset also consists of any lease incentives received. The lease terms used to calculate the ROU asset and related lease liability include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. “Reasonably certain” is assessed internally based on economic, industry, company, strategic and contractual factors. The leases have remaining lease terms of 1 year to 15 years, some of which include options to extend the lease for up to 10 years, and some of which include options to terminate the lease within 1 year. Operating lease expense and amortization of finance lease ROU assets are recognized on a straight-line basis over the lease term as an operating expense. Finance lease interest expense is recorded as interest expense on the Company’s consolidated statements of operations. The Company accounts for leases acquired in business combinations by measuring the lease liability at the present value of the remaining lease payments as if the acquired lease were a new lease for the Company. This measurement includes recognition of a lease intangible for any below-market terms present in the leases acquired. The below-market lease intangible is included in the ROU asset on the consolidated balance sheets and are amortized over the remaining lease term. The Company has not acquired any leases with above-market terms.
Revenue Recognition	Revenue Recognition Revenues are recognized when the satisfaction of the performance obligation occurs, in an amount that reflects the consideration the Company expects to collect in exchange for those services. To determine revenue recognition for the arrangements that the Company determines are within the scope of FASB ASC Topic 606, Revenue from Contracts with Customers, the Company performs the following five steps: (1) identify the contract(s) with a customer, (2) identify the performance obligations in the contract, (3) determine the transaction price, (4) allocate the transaction price to the performance obligations in the contract and (5) recognize revenue when (or as) the entity satisfies a performance obligation. See Note 2 for further discussion.
Foreign Currency Transactions	Foreign Currency Transactions Prior to 2019, the Company’s international subsidiaries’ functional currency was the local currency and assets and liabilities were translated into U.S. dollars at the period-end exchange rate or historical rates, as appropriate. Consolidated statements of operations were translated at average exchange rates for the period, and the cumulative translation adjustments resulting from changes in exchange rates were included in the Company’s consolidated balance sheet as a component of additional paid-in capital. In 2019 and 2020, the Company’s international subsidiaries use the U.S. dollar as the functional currency, resulting in the Company not being subject to gains and losses from foreign currency translation of the subsidiary financial statements. The Company recognizes gains and losses from foreign currency transactions in the consolidated statements of operations. Net foreign currency transaction gains or losses were not material to the consolidated statements of operations for the periods presented.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that subject the Company to credit risk consist of cash, cash equivalents and marketable securities. As of December 31, 2020, the Company had cash and cash equivalents deposited in financial institutions in which the balances exceed the federal government agency insured limit of $250,000 by approximately $237.0 million. The Company has not experienced any losses in such accounts and management believes it is not exposed to any significant credit risk. Through December 31, 2020, the Company’s revenues have been primarily derived from the sale of Cologuard, Oncotype DX, and COVID-19 tests. The following is a breakdown of revenue and accounts receivable from major payers: % Revenue for the years ended December 31, % Accounts Receivable at December 31, Major Payer 2020 2019 2018 2020 2019 2018 Centers for Medicare and Medicaid Services 21% 29% 36% 14% 19% 32% UnitedHealthcare 10% 13% 13% 7% 7% 10% State of Wisconsin 12% —% —% 22% —% —%
Tax Positions	Tax Positions A valuation allowance to reduce the deferred tax assets is reported if, based on the weight of the evidence, it is more likely than not that some portion or all of the deferred tax assets will not be realized. The Company has incurred significant losses since its inception and due to the uncertainty of the amount and timing of future taxable income, the Company has determined that a $157.6 million and $120.7 million valuation allowance at December 31, 2020 and 2019 is necessary to reduce the tax assets to the amount that is more likely than not to be realized. The change in valuation allowance as of December 31, 2020 and 2019 was an increase of $36.9 million and a decrease of $89.2 million, respectively. An income tax benefit of $8.6 million was recorded primarily as a result of future limitations on and expiration of certain Federal and State deferred tax assets. Due to the existence of the valuation allowance, future changes in our unrecognized tax benefits will not impact our effective tax rate.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Recently Adopted Accounting Pronouncements In June 2016, the FASB issued Accounting Standards Update ("ASU") No. 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments . The updated guidance requires companies to measure all expected credit losses for financial instruments held at the reporting date based on historical experience, current conditions, and reasonable supportable forecasts. This replaces the existing incurred loss model and is applicable to the measurement of credit losses on financial assets, including trade receivables. The updates also require available-for-sale debt security credit losses to be recognized as allowances rather than a reduction in amortized cost. The guidance was adopted by the Company on January 1, 2020. The requirements of the ASU did not result in the recognition of a material allowance for current expected credit losses, as the Company’s analysis of collectability looks at historical experience as well as current and future implications surrounding the ability to collect. Adoption of the updated guidance did not have a material impact on the Company’s consolidated financial statements. In April 2019, the FASB issued ASU 2019-04, Codification Improvements to Topic 326, Financial Instruments –Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments . The updated guidance provides clarity regarding measurement of securities without readily determinable fair values. The guidance was adopted on January 1, 2020 and did not have a material impact on the Company's consolidated financial statements. In August 2018, the FASB issued ASU 2018-15, Intangibles –Goodwill and Other –Internal-Use Software (Subtopic 350-40) . The update provided guidance for evaluating the accounting for fees paid by a customer in a cloud computing arrangement that is a service contract. The guidance was adopted on a prospective basis, beginning on January 1, 2020 and it did not have a material impact on the Company's consolidated financial statements. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820); Disclosure Framework — Changes to the Disclosure Requirements for Fair Value Measurement . The guidance provided an update to the disclosure requirements for fair value measurements under the scope of ASC 820. The updates were adopted on January 1, 2020 and did not have a material impact on the Company’s consolidated financial statements. In November 2018, the FASB issued ASU 2018-18, Collaborative Arrangements (Topic 808) . The update provided additional guidance regarding the interaction between Topic 808 on Collaborative Arrangements and Topic 606 on Revenue Recognition. The guidance was adopted on January 1, 2020 and did not have a material impact on the Company's consolidated financial statements. In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes . The update simplifies the accounting for income taxes through removing exceptions related to certain intraperiod allocations and deferred tax liabilities; clarifying guidance primarily related to evaluating the step-up tax basis for goodwill in a business combination; and reflecting enacted changes in tax laws or rates in the annual effective tax rate. The amended guidance is effective for interim and annual periods in 2021, however early adoption is permitted. The guidance was early adopted on January 1, 2020 and did not have a material impact on the Company’s consolidated financial statements. In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting . The updated guidance provides optional expedients for applying the requirements of certain topics in the codification for contracts that are modified because of reference rate reform. In addition to the optional expedients, the update includes a general principle that permits an entity to consider contract modifications due to reference rate reform to be an event that does not require contract remeasurement at the modification date or reassessment of a previous accounting determination. The updated guidance is effective for all entities as of March 12, 2020 and through December 31, 2022. The Company adopted the guidance upon issuance on March 12, 2020. There was no impact on the Company's consolidated financial statements. Recently Issued Accounting Pronouncements Not Yet Adopted In August 2020, The Financial Accounting Standards Board issued ASU No. 2020-06, Debt – Debt with Conversion and Other Options (subtopic 470-20) and Derivatives and Hedging – Contracts in Entity’s Own Equity (Subtopic 815-40) . This update simplifies the accounting for convertible debt instruments by removing the beneficial conversion and cash conversion separation models for convertible instruments. Under the update, the embedded conversion features are no longer separated from the host contract for convertible instruments with conversion features that are not required to be accounted for as derivatives or that do not result in substantial premiums accounted for as paid-in capital. The update also amends the accounting for certain contracts in an entity’s own equity that are currently accounted for as derivatives because of specific settlement provisions. In addition, the new guidance modifies how particular convertible instruments and certain contracts that may be settled in cash or shares impact the computation of diluted earnings per share. The amendments in this update are effective for fiscal years beginning after December 15, 2021, including interim periods within those fiscal years. Early adoption is permitted, but no earlier than fiscal years beginning after December 15, 2020. The Company is currently evaluating the impact of this guidance on its consolidated financial statements.
Guarantees and Indemnifications	Guarantees and Indemnifications The Company, as permitted under Delaware law and in accordance with its bylaws, indemnifies its officers and directors for certain events or occurrences, subject to certain limits, while the officer or director is or was serving at the Company’s request in such capacity. The term of the indemnification period is for the officer’s or director’s lifetime. The maximum amount of potential future indemnification is unlimited; however, the Company has a directors and officers insurance policy that limits its exposure and may enable it to recover a portion of any future amounts paid. The Company believes the fair value of these indemnification agreements is minimal. Accordingly, the Company has not recorded any liabilities for these agreements as of December 31, 2020 and 2019.
Reclassifications	Reclassifications Certain prior year amounts have been reclassified to conform to the current year presentation in the consolidated financial statements and accompanying notes to the consolidated financial statements.

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Schedule of potentially issuable common shares not included in the computation of diluted net loss per share because they would have an anti-dilutive effect	The following potentially issuable common shares were not included in the computation of diluted net loss per share because they would have an anti-dilutive effect due to net losses for each period: December 31, (In thousands) 2020 2019 2018 Shares issuable in connection with acquisitions 157 — — Shares issuable upon exercise of stock options 2,231 2,700 2,532 Shares issuable upon the release of restricted stock awards 3,968 3,801 3,847 Shares issuable upon the release of performance share units 619 583 2,399 Shares issuable upon conversion of convertible notes 20,309 12,196 12,044 27,284 19,280 20,822
Schedules of concentration of risk	The following is a breakdown of revenue and accounts receivable from major payers: % Revenue for the years ended December 31, % Accounts Receivable at December 31, Major Payer 2020 2019 2018 2020 2019 2018 Centers for Medicare and Medicaid Services 21% 29% 36% 14% 19% 32% UnitedHealthcare 10% 13% 13% 7% 7% 10% State of Wisconsin 12% —% —% 22% —% —%

REVENUE (Tables)

REVENUE (Tables)	12 Months Ended
	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Schedule of disaggregation by revenue source	The following table presents the Company's revenues disaggregated by revenue source: Year Ended December 31, (In thousands) 2020 2019 2018 Screening Medicare Parts B & C $ 365,471 $ 404,331 $ 254,431 Commercial 409,671 368,006 184,538 Other 39,925 37,783 15,493 Total Screening 815,067 810,120 454,462 Precision Oncology Medicare Parts B & C $ 157,166 $ 24,325 $ — Commercial 186,043 29,976 — International 77,484 11,444 — Other 19,800 428 — Total Precision Oncology 440,493 66,173 — COVID-19 Testing $ 235,831 $ — $ — Total $ 1,491,391 $ 876,293 $ 454,462

MARKETABLE SECURITIES (Tables)

MARKETABLE SECURITIES (Tables)	12 Months Ended
	Dec. 31, 2020
Cash and Cash Equivalents [Abstract]
Schedule of cash and cash equivalents	The following table sets forth the Company’s cash, cash equivalents, restricted cash, and marketable securities at December 31, 2020 and 2019: December 31, (In thousands) 2020 2019 Cash, cash equivalents, and restricted cash Cash and money market $ 901,294 $ 146,932 Cash equivalents 589,994 30,322 Restricted cash (1) 306 274 Total cash, cash equivalents and restricted cash 1,491,594 177,528 Marketable securities Available-for-sale debt securities 347,178 144,685 Equity securities 1,521 1,716 Total marketable securities 348,699 146,401 Total cash and cash equivalents, restricted cash and marketable securities $ 1,840,293 $ 323,929 _________________________________ (1) Restricted cash is included in other long-term assets on the consolidated balance sheets. There was no restricted cash at December 31, 2018.
Schedule of restricted cash and cash equivalents	The following table sets forth the Company’s cash, cash equivalents, restricted cash, and marketable securities at December 31, 2020 and 2019: December 31, (In thousands) 2020 2019 Cash, cash equivalents, and restricted cash Cash and money market $ 901,294 $ 146,932 Cash equivalents 589,994 30,322 Restricted cash (1) 306 274 Total cash, cash equivalents and restricted cash 1,491,594 177,528 Marketable securities Available-for-sale debt securities 347,178 144,685 Equity securities 1,521 1,716 Total marketable securities 348,699 146,401 Total cash and cash equivalents, restricted cash and marketable securities $ 1,840,293 $ 323,929 _________________________________ (1) Restricted cash is included in other long-term assets on the consolidated balance sheets. There was no restricted cash at December 31, 2018.
Schedule of available-for-sale securities	Available-for-sale debt securities at December 31, 2020 consisted of the following: (In thousands) Amortized Cost Gains in Accumulated Losses in Accumulated Other Comprehensive Income (Loss) (1) Estimated Fair Cash equivalents U.S. government agency securities $ 589,986 $ 8 $ — $ 589,994 Total cash equivalents 589,986 8 — 589,994 Marketable securities Corporate bonds 132,301 612 — 132,913 U.S. government agency securities 207,119 52 — 207,171 Asset backed securities 7,070 24 — 7,094 Total marketable securities 346,490 688 — 347,178 Total available-for-sale debt securities $ 936,476 $ 696 $ — $ 937,172 _________________________________ (1) Gains and losses in accumulated other comprehensive income (loss)("AOCI") are reported before tax impact. Available-for-sale debt securities at December 31, 2019 consisted of the following: (In thousands) Amortized Cost Gains in Accumulated Losses in Accumulated Estimated Fair Cash equivalents U.S. government agency securities $ 30,320 $ 2 $ — $ 30,322 Total cash equivalents 30,320 2 — 30,322 Marketable securities Corporate bonds 4,017 — (14) 4,003 U.S. government agency securities 140,745 10 (73) 140,682 Total marketable securities 144,762 10 (87) 144,685 Total available-for-sale debt securities $ 175,082 $ 12 $ (87) $ 175,007 _________________________________ (1) There was no tax impact on the gains and losses in accumulated income (loss) at December 31, 2019.
Schedule of contractual maturities of available-for-sale investments	The following table summarizes contractual underlying maturities of the Company’s available-for-sale debt securities at December 31, 2020: Due one year or less Due after one year through four years (In thousands) Cost Fair Value Cost Fair Value Cash equivalents U.S. government agency securities $ 589,986 $ 589,994 $ — $ — Total cash equivalents 589,986 589,994 — — Marketable securities U.S. government agency securities 199,988 199,994 7,131 7,177 Corporate bonds 100,837 101,122 31,464 31,791 Asset backed securities — — 7,070 7,094 Total marketable securities 300,825 301,116 45,665 46,062 Total available-for-sale securities $ 890,811 $ 891,110 $ 45,665 $ 46,062
Schedule of gross unrealized losses and fair values of investments in an unrealized loss position	The following table summarizes the gross unrealized losses and fair value of available-for-sale debt securities in an unrealized loss position as of December 31, 2019, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position: Less than 12 months 12 months or greater Total (In thousands) Fair Value Gross Unrealized Loss Fair Value Gross Unrealized Loss Fair Value Gross Unrealized Loss Marketable Securities Corporate bonds $ 4,003 $ (14) $ — $ — $ 4,003 $ (14) Asset backed securities 140,682 (73) — — 140,682 (73) Total $ 144,685 $ (87) $ — $ — $ 144,685 $ (87)

INVENTORY (Tables)

INVENTORY (Tables)	12 Months Ended
	Dec. 31, 2020
Inventory Disclosure [Abstract]
Schedule of inventory	Inventory consisted of the following: December 31, (In thousands) 2020 2019 Raw materials $ 43,083 $ 24,958 Semi-finished and finished goods 49,182 36,766 Total inventory $ 92,265 $ 61,724

PROPERTY, PLANT, AND EQUIPMENT

PROPERTY, PLANT, AND EQUIPMENT (Tables)	12 Months Ended
	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Schedule of property, plant and equipment, net	The estimated useful lives of property, plant and equipment are as follows: December 31, (In thousands) Estimated 2020 2019 Property, plant and equipment Land n/a $ 4,466 $ 4,466 Leasehold and building improvements (1) 117,865 80,352 Land improvements 15 years 4,864 1,766 Buildings 30 - 40 years 200,980 112,815 Computer equipment and computer software 3 years 73,296 65,323 Laboratory equipment 3 - 10 years 142,110 104,008 Furniture and fixtures 3 - 10 years 24,968 14,539 Assets under construction n/a 18,751 149,687 Property, plant and equipment, at cost 587,300 532,956 Accumulated depreciation (136,617) (77,631) Property, plant and equipment, net $ 450,683 $ 455,325 _________________________________ (1) Lesser of remaining lease term, building life, or estimated useful life.

INTANGIBLE ASSETS AND GOODWILL

INTANGIBLE ASSETS AND GOODWILL (Tables)	12 Months Ended
	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of net-book value and estimated remaining life and finite lived intangible assets	The following table summarizes the net-book-value and estimated remaining life of the Company's intangible assets as of December 31, 2020: (In thousands) Weighted Cost Accumulated Amortization Net Balance at December 31, 2020 Finite-lived intangible assets Trade name 14.9 $ 100,700 $ (7,258) $ 93,442 Customer relationships 12.8 2,700 (404) 2,296 Patents 3.7 10,441 (5,422) 5,019 Supply agreement 6.5 30,000 (4,527) 25,473 Acquired developed technology 9.0 814,171 (93,278) 720,893 Internally developed technology 2.2 2,121 (921) 1,200 Total finite-lived intangible assets 960,133 (111,810) 848,323 Internally developed technology in process n/a 103 — 103 Total intangible assets $ 960,236 $ (111,810) $ 848,426 The following table summarizes the net-book-value and estimated remaining life of the Company’s finite-lived intangible assets as of December 31, 2019: (In thousands) Weighted Cost Accumulated Amortization Net Balance at December 31, 2019 Finite-lived intangible assets Trade name 15.9 $ 100,700 $ (961) $ 99,739 Customer relationships 13.8 2,700 (224) 2,476 Patents 8.8 22,690 (5,975) 16,715 Supply agreement 7.5 30,000 (571) 29,429 Acquired developed technology 9.9 806,371 (12,344) 794,027 Internally developed technology 2.5 1,229 (336) 893 Total finite-lived intangible assets 963,690 (20,411) 943,279 In-process research and development n/a 200,000 — 200,000 Internally developed technology in process n/a 271 — 271 Total intangible assets $ 1,163,961 $ (20,411) $ 1,143,550
Schedule of estimated future amortization expense, intangible assets	As of December 31, 2020, the estimated future amortization expense associated with the Company’s finite-lived intangible assets for each of the five succeeding fiscal years is as follows: (In thousands) 2021 $ 93,401 2022 93,196 2023 92,876 2024 92,422 2025 91,374 Thereafter 385,054 $ 848,323
Schedule of carrying amount of goodwill	The change in the carrying amount of goodwill for the years ended December 31, 2020 and 2019 is as follows: (In thousands) Balance, January 1, 2019 (1) $ 17,279 Genomic Health acquisition 1,185,918 Balance, December 31, 2019 1,203,197 Paradigm & Viomics acquisition 30,431 Genomic Health acquisition adjustment (2) 4,044 Balance, December 31, 2020 $ 1,237,672 _________________________________ (1) The beginning balance represents the goodwill acquired from the acquisitions of Sampleminded, Inc. in 2017 and Biomatrica, Inc. in 2018 totaling $2.0 million and $15.3 million, respectively.

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Schedule of fair value measurements along with the level within the fair value hierarchy in which the fair value measurements fall	The following table presents the Company’s fair value measurements as of December 31, 2020 along with the level within the fair value hierarchy in which the fair value measurements, in their entirety, fall. (In thousands) Fair value at December 31, 2020 Quoted Prices Significant Significant Cash, cash equivalents, and restricted cash Cash and money market $ 901,294 $ 901,294 $ — $ — U.S. government agency securities 589,994 — 589,994 — Restricted cash 306 306 — — Marketable securities Corporate bonds 132,913 — 132,913 — U.S. government agency securities 207,171 — 207,171 — Asset backed securities 7,094 — 7,094 — Equity securities 1,521 1,521 — — Liabilities Contingent consideration (2,477) — — (2,477) Total $ 1,837,816 $ 903,121 $ 937,172 $ (2,477) The following table presents the Company’s fair value measurements as of December 31, 2019 along with the level within the fair value hierarchy in which the fair value measurements, in their entirety, fall. (In thousands) Fair Value at December 31, 2019 Quoted Prices Significant Significant Cash and cash equivalents Cash and money market $ 146,932 $ 146,932 $ — $ — U.S. government agency securities 30,322 — 30,322 — Restricted cash 274 274 — — Marketable securities Corporate bonds 4,003 — 4,003 — U.S. government agency securities 140,682 — 140,682 — Equity securities 1,716 1,716 — — Liabilities Contingent consideration (2,879) — — (2,879) Total $ 321,050 $ 148,922 $ 175,007 $ (2,879)
Schedule of fair value of contingent consideration	The following table provides a roll-forward of the fair values of the contingent consideration, which includes Level 3 measurements: (In thousands) Contingent consideration Balance, January 1, 2020 $ (2,879) Changes in fair value 325 Payments 77 Balance, December 31, 2020 $ (2,477)
Schedule of carrying values and estimated fair values of convertible notes and long-term debt instruments	The following table summarizes the Company’s outstanding convertible notes and long-term debt: December 31, 2020 December 31, 2019 (In thousands) Carrying Amount (1) Fair Value Carrying Amount (1) Fair Value 2028 Convertible notes (2) $ 806,587 $ 1,526,625 $ — $ — 2027 Convertible notes (2) 514,173 992,306 483,909 843,741 2025 Convertible notes (2) 255,464 601,744 319,696 592,482 Construction loan (3) 23,661 23,661 24,866 24,866 _________________________________ (1) The carrying amounts presented are net of debt discounts and debt issuance costs. See Note 9 and Note 10 of the consolidated financial statements for further information. (2) The fair values are based on observable market prices for this debt, which is traded in active markets and therefore is classified as a Level 2 fair value measurement. A portion of the 2025 convertible notes were settled in 2019 resulting in a decrease in the liability. (3) The carrying amount of the construction loan approximates fair value due to the short-term nature of this instrument. The construction loan is privately held with no public market for this debt and therefore is classified as a Level 3 fair value measurement. The change in the fair value was due to payments made on the loan resulting in a decrease in the liability.

ACCRUED LIABILITIES (Tables)

ACCRUED LIABILITIES (Tables)	12 Months Ended
	Dec. 31, 2020
Payables and Accruals [Abstract]
Schedule of accrued expenses	Accrued liabilities at December 31, 2020 and 2019 consisted of the following: December 31, (In thousands) 2020 2019 Compensation $ 117,273 $ 95,166 Pfizer Promotion Agreement related costs 46,937 33,230 Professional fees 36,113 29,108 Other 20,735 13,976 Assets under construction 2,118 10,720 Research and trial related expenses 5,911 8,368 Licenses 4,517 2,761 $ 233,604 $ 193,329

LONG TERM DEBT (Tables)

LONG TERM DEBT (Tables)	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Schedule of future principal obligations	The table below represents the future principal obligations as of December 31, 2020. Amounts included in the table are in thousands: Year ending December 31 2021 $ 1,319 2022 22,431 Total $ 23,750

CONVERTIBLE DEBT (Tables)

CONVERTIBLE DEBT (Tables)	12 Months Ended
	Dec. 31, 2020
CONVERTIBLE DEBT
Schedule of debt, net of discounts and deferred financing costs	Convertible note obligations included in the consolidated balance sheets consisted of the following: December 31, (In thousands) Coupon Interest Rate Effective Interest Rate Fair Value of Liability Component at Issuance (1) 2020 2019 2028 Convertible notes 0.375 % 5.2 % $ 790,608 $ 1,150,000 $ — 2027 Convertible notes 0.375 % 6.3 % 472,501 747,500 747,500 2025 Convertible notes 1.000 % 6.0 % 227,103 315,049 415,049 Total Convertible notes 2,212,549 1,162,549 Less: Debt discount (2) (608,685) (342,463) Less: Debt issuance costs (3) (27,640) (16,481) Net convertible debt including current maturities 1,576,224 803,605 Less: Current maturities (4) (255,464) — Net long-term convertible debt $ 1,320,760 $ 803,605 _________________________________ (1) As each of the convertible instruments may be settled in cash upon conversion, for accounting purposes, they were separated into a liability component and an equity component. The amount allocated to the equity component is the difference between the principal value of the instrument and the fair value of the liability component at issuance. The resulting debt discount is being amortized to interest expense at the respective effective interest rate over the contractual term of the debt. A portion of the 2025 Convertible Notes have been extinguished or converted. The fair value of the liability component at issuance reflected above represents the liability value at issuance for the applicable portion of the 2025 Notes which remain outstanding at December 31, 2020. The fair value of the liability component of the 2025 Notes at issuance was $654.8 million with the equity component being $267.9 million. (2) The unamortized discount consists of the following: December 31, (In thousands) 2020 2019 2028 Convertible notes $ 328,372 $ — 2027 Convertible notes 224,517 253,340 2025 Convertible notes 55,796 89,123 Total unamortized discount $ 608,685 $ 342,463 (3) Debt issuance costs consist of the following: December 31, (In thousands) 2020 2019 2028 Convertible notes $ 15,041 $ — 2027 Convertible notes 8,810 10,251 2025 Convertible notes 3,789 6,230 Total debt issuance costs $ 27,640 $ 16,481
Schedule of Allocation of Transaction Costs Related to Convertible Debt	The following table summarizes the original transaction costs at the time of issuance for each set of Notes and the respective allocation to the liability and equity components: (In thousands) January 2025 Notes June 2025 Notes 2027 Notes 2028 Notes Transaction costs allocated to liability component $ 13,569 $ 5,052 $ 11,395 $ 16,811 Transaction costs allocated to equity component 5,340 2,311 6,632 7,642 Total transaction costs $ 18,909 $ 7,363 $ 18,027 $ 24,453
Schedule of Interest Expense	Interest expense includes the following: Year Ended December 31, (In thousands) 2020 2019 2018 Debt issuance costs amortization $ 4,207 $ 2,661 $ 2,273 Debt discount amortization 72,272 39,595 26,291 Loss on settlement of convertible notes 7,954 10,558 — Coupon interest expense 9,631 7,325 7,823 Total interest expense on convertible notes 94,064 60,139 36,387 Other interest expense 1,919 1,460 402 Total interest expense $ 95,983 $ 61,599 $ 36,789

STOCKHOLDERS' EQUITY (Tables)

STOCKHOLDERS' EQUITY (Tables)	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Schedule of amounts recognized in accumulated other comprehensive income (loss) (AOCI)	The amount recognized in AOCI for the years ended December 31, 2020, 2019 and 2018 were as follows: (In thousands) Cumulative Unrealized Accumulated Balance, January 1, 2018 $ (61) $ (689) $ (750) Other comprehensive income (loss) before reclassifications 36 (1,025) (989) Amounts reclassified from accumulated other comprehensive loss — 317 317 Net current period change in accumulated other comprehensive income (loss) (1) 36 (708) (672) Balance at December 31, 2018 $ (25) $ (1,397) $ (1,422) Other comprehensive income (loss) before reclassifications — 681 681 Amounts reclassified from accumulated other comprehensive loss — 641 641 Net current period change in accumulated other comprehensive income (loss) (1) — 1,322 1,322 Balance at December 31, 2019 $ (25) $ (75) $ (100) Other comprehensive income (loss) before reclassifications — 771 771 Amounts reclassified from accumulated other comprehensive loss 25 — 25 Net current period change in accumulated other comprehensive income (loss) 25 771 796 Balance at Income tax expense related to items of other comprehensive income — (170) (170) Balance at December 31, 2020 $ — $ 526 $ 526 _________________________________ (1) There was no tax impact from the amounts recognized in AOCI for the years ended December 31, 2019 and 2018.
Schedule of amounts reclassified from accumulated other comprehensive income (loss)	Amounts reclassified from accumulated other comprehensive loss for the years ended December 31, 2020, 2019 and 2018 were as follows: Year Ended December 31, Details about AOCI Components (In thousands) Affected Line Item in the 2020 2019 2018 Change in value of available-for-sale investments Sales and maturities of available-for-sale investments Investment income $ — $ 641 $ 317 Foreign currency adjustment General and administrative 25 — — Total reclassifications $ 25 $ 641 $ 317

STOCK-BASED COMPENSATION (Table

STOCK-BASED COMPENSATION (Tables)	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Schedule of non-cash stock-based compensation expense by department	A summary of non-cash stock-based compensation expense by expense category included in the Company's consolidated statements of operations for the years ended December 31, 2020, 2019, and 2018 is as follows: Year Ended December 31, (In thousands) 2020 2019 2018 Cost of sales $ 12,852 $ 5,799 $ 3,531 Research and development 19,976 17,196 10,189 General and administrative 75,999 64,222 34,181 Sales and marketing 44,079 21,266 12,363 Total stock-based compensation $ 152,906 $ 108,483 $ 60,264
Schedule of valuation assumptions	The Company determines the fair value of each service-based option award on the date of grant using the Black-Scholes option-pricing mode, which utilizes several key assumptions which are disclosed in the following table: Year Ended December 31 2020 2019 2018 Option Plan Shares Risk-free interest rates 1.26% - 1.47% 2.54% - 2.59% 2.73% - 2.79% Expected term (in years) 6.15 6.28 5.45 - 6.44 Expected volatility 65.67% - 65.71% 64.95% - 64.99% 61.82% - 66.17% Dividend yield 0% 0% 0% The fair value of ESPP shares is based on the assumptions in the following table: Year Ended December 31, 2020 2019 2018 ESPP Shares Risk-free interest rates 0.11% - 0.2% 1.6% - 2.4% 2.1% - 2.8% Expected term (in years) 0.5 - 2 0.4 - 2 0.5 - 2 Expected volatility 61.59% - 89.0% 43.2% - 57.6% 51.7% - 65.4% Dividend yield 0% 0% 0%
Summary of stock option activity under the Stock Plans	A summary of stock option activity under the Stock Plans is as follows: Options Shares Weighted Weighted Aggregate (Aggregate intrinsic value in thousands) Outstanding, January 1, 2020 2,700,293 $ 34.01 6.7 Granted 309,143 97.66 Exercised (707,013) 39.07 Forfeited (71,364) 82.76 Outstanding, December 31, 2020 2,231,059 $ 39.67 6.0 $ 207,090 Vested and expected to vest, December 31, 2020 2,231,059 $ 39.67 6.0 $ 207,090 Exercisable, December 31, 2020 1,399,721 $ 22.53 4.9 $ 153,912 _________________________________ (1) The weighted average grant date fair value of options granted during the years ended December 31, 2020, 2019, and 2018 was $58.57, $57.11, and $24.55. (2) The total intrinsic value of options exercised during the years ended December 31, 2020, 2019, and 2018 was $40.6 million, $52.0 million, and $53.0 million, respectively, determined as of the date of exercise.
Summary of restricted stock and restricted stock unit activity under the Stock Plans	A summary of restricted stock and restricted stock unit activity is as follows: Restricted Weighted Outstanding, January 1, 2020 3,800,722 $ 58.68 Granted 2,236,535 92.55 Released (1) (1,731,631) 50.67 Forfeited (337,412) 81.36 Outstanding, December 31, 2020 3,968,214 $ 79.38 _________________________________ (1) The fair value of restricted stock units vested and converted to shares of the Company's common stock was $152.4 million, $173.8 million, and $63.8 million for the years ended December 31, 2020, 2019, and 2018, respectively. (2) The weighted average grant date fair value of the restricted stock units granted during the years ended December 31, 2019 and 2018 was $93.20, and $50.45, respectively.
Share-based Payment Arrangement, Performance Shares, Activity	A summary of performance share unit activity is as follows: Performance Share Units (2) Weighted Outstanding, December 31, 2019 583,283 $ 93.40 Granted 35,232 90.17 Released (1) — — Forfeited — — Outstanding, December 31, 2020 618,515 $ 93.22 _________________________________ (1) The fair value of performance share units vested and converted to shares of the Company's common stock was $183.8 million for the year ended December 31, 2019. There were no performance share units vested and converted to shares of the Company's common stock during the years ended December 31, 2020 and 2018. (2) Participants may ultimately earn between zero and 200% of the target number of performance share units granted based on the degree of achievement of the performance criteria. The performance share units listed above assumes attainment of maximum payout rates as set forth in the performance criteria. Applying actual or expected payout rates, the number of outstanding performance share units as of December 31, 2020 was 158,958. (3) The weighted average grant date fair value of the performance share units granted during the years ended December 31, 2019 was $93.40. There were no performance share units granted during the year ended December 31, 2018.
Schedule of shares of common stock issued	A summary of ESPP activity is as follows: Year Ended December 31, (in thousands, except share and per share amounts) 2020 2019 2018 Shares issued under the 2010 Purchase Plan 301,064 176,458 346,609 Cash received under the 2010 Purchase Plan $ 18,355 $ 8,396 $ 4,895 Weighted average fair value per share of stock purchase rights granted during the period $ 32.57 $ 29.21 $ 20.47
Schedule of Common Stock Issued	The 301,064 shares issued during the year ended December 31, 2020 were as follows: Offering period ended Number of Shares Weighted Average price per Share April 30, 2020 167,921 $ 57.95 November 2, 2020 133,143 $ 64.35
Summary of shares of authorized common stock reserved for issuance	The Company has reserved shares of its authorized common stock for issuance pursuant to its employee stock purchase and equity plans, including all outstanding stock option grants noted above at December 31, 2020, as follows: Shares reserved for issuance 2019 Stock Plan 11,898,737 2010 Purchase Plan 759,015 12,657,752

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Components of lease expense	The components of lease expense were as follows: Year Ended December 31, (In thousands) 2020 2019 Finance lease cost Amortization of right-of-use assets $ 1,935 $ 27 Interest on lease liabilities 383 2 Operating lease cost 22,551 9,200 Short-term lease cost 356 219 Variable lease cost 2,703 896 Total Lease Cost $ 27,928 $ 10,344 Year Ended December 31, (In thousands) 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 17,531 $ 9,641 Operating cash flows from finance leases 381 1 Finance cash flows from finance leases 1,756 15 Non-cash investing and financing activities: Right-of-use assets obtained in exchange for new operating lease liabilities (1) 13,261 51,030 Right-of-use assets obtained in exchange for new finance lease liabilities 20,349 237 Weighted-average remaining lease term - operating leases (in years) 8.75 9.80 Weighted-average remaining lease term - finance leases (in years) 3.68 1.20 Weighted-average discount rate - operating leases 6.80 % 6.80 % Weighted-average discount rate - finance leases 5.67 % 5.60 % _________________________________ (1) For the year ended December 31, 2019, this includes right-of-use assets obtained from the initial adoption of ASC 842 of approximately $17.9 million.
Operating lease maturity	Maturities of operating lease liabilities on an annual basis as of December 31, 2020 were as follows (amounts in thousands): (In thousands) 2021 $ 19,881 2022 19,596 2023 21,306 2024 21,257 2025 19,338 Thereafter 79,141 Total minimum lease payments 180,519 Imputed interest (47,961) Total $ 132,558
Finance Lease, Liability, Fiscal Year Maturity	Maturities of finance lease liabilities on an annual basis as of December 31, 2020 were as follows (amounts in thousands): (In thousands) 2021 $ 5,674 2022 5,635 2023 5,525 2024 3,819 2025 53 Thereafter — Total minimum lease payments 20,706 Imputed interest (1,961) Total $ 18,745

BUSINESS COMBINATIONS AND ASSET

BUSINESS COMBINATIONS AND ASSET ACQUISITIONS (Tables)	12 Months Ended
	Dec. 31, 2020
Business Combinations [Abstract]
Schedule of allocated to the underlying assets acquired and liabilities assumed	The purchase price was allocated to the underlying assets acquired and liabilities assumed based upon their estimated fair values as follows: (In thousands) Preliminary Allocation Measurement Period Preliminary Allocation Net operating assets $ 6,133 $ (760) $ 5,373 Goodwill 29,695 736 30,431 Developed technology 7,800 — 7,800 Net operating liabilities (3,123) (80) (3,203) Total purchase price $ 40,505 $ (104) $ 40,401 The combination date fair value of the consideration transferred for Genomic Health was approximately $2.47 billion, which consisted of the following: (In thousands) Cash $ 1,061,489 Common stock issued 1,389,266 Fair value of replacement stock options and restricted stock awards 17,813 Total purchase price $ 2,468,568 The purchase price was allocated to the underlying assets acquired and liabilities assumed based upon their estimated fair values as follows: (In thousands) Preliminary Allocation Measurement Period Final Allocation Cash and cash equivalents $ 87,627 $ — $ 87,627 Marketable securities 201,519 — 201,519 Accounts receivable 57,400 — 57,400 Inventory 3,535 — 3,535 Prepaid expenses and other current assets 8,360 — 8,360 Property, plant and equipment 69,905 (122) 69,783 Goodwill 1,185,918 4,044 1,189,962 Trade name 100,000 — 100,000 Supply agreement intangible 30,000 — 30,000 Developed technology 800,000 — 800,000 In-process research and development (IPR&D) 200,000 — 200,000 Operating lease right-of-use assets 80,790 — 80,790 Other long-term assets 14,972 (96) 14,876 Accounts payable, accrued liabilities and other current liabilities (88,995) 548 (88,447) Deferred tax liability (205,536) (4,374) (209,910) Operating lease liabilities, current portion (3,258) — (3,258) Operating lease liabilities, less current portion (71,270) — (71,270) Other long-term liabilities (2,399) — (2,399) Total fair value consideration $ 2,468,568 $ — $ 2,468,568 The following table summarizes the total consideration for the acquisition and the value of assets acquired and liabilities assumed as of October 26, 2020, the Merger closing date. These values are based on internal Company and independent external third-party valuations: (In thousands) Consideration Cash paid for acquisition of Base Genomics outstanding shares $ 416,525 Transaction costs 4,600 Total consideration 421,125 Assets acquired and liabilities assumed Cash 9,704 IPR&D asset 412,568 Other assets and liabilities (1,147) Net assets acquired $ 421,125
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions	Th e fair value of options assumed were based on the assumptions in the following table: Option Plan Shares Assumed Risk-free interest rates 0.88% - 2.90% Expected term (in years) 3.28 - 6.73 Expected volatility 63.54% - 69.09% Dividend yield 0% Weighted average fair value per share of options assumed $45.75 - $57.44
Schedule of valuation assumptions	The Company determines the fair value of each service-based option award on the date of grant using the Black-Scholes option-pricing mode, which utilizes several key assumptions which are disclosed in the following table: Year Ended December 31 2020 2019 2018 Option Plan Shares Risk-free interest rates 1.26% - 1.47% 2.54% - 2.59% 2.73% - 2.79% Expected term (in years) 6.15 6.28 5.45 - 6.44 Expected volatility 65.67% - 65.71% 64.95% - 64.99% 61.82% - 66.17% Dividend yield 0% 0% 0% The fair value of ESPP shares is based on the assumptions in the following table: Year Ended December 31, 2020 2019 2018 ESPP Shares Risk-free interest rates 0.11% - 0.2% 1.6% - 2.4% 2.1% - 2.8% Expected term (in years) 0.5 - 2 0.4 - 2 0.5 - 2 Expected volatility 61.59% - 89.0% 43.2% - 57.6% 51.7% - 65.4% Dividend yield 0% 0% 0%
Business combination, pro forma information	The amounts of revenue and net loss before tax of Genomic Health included in the Company’s consolidated statement of operations from the combination date of November 8, 2019 to December 31, 2019 and for the year ended December 31, 2020 are as follows: (In thousands) 2020 2019 Total revenues $ 435,960 $ 66,174 Net loss before tax (254,162) (40,446) The following unaudited pro forma financial information summarized the combined results of operations for the Company and Genomic Health, as though the companies were combined as of the beginning of January 1, 2018. Year Ended December 31, (In thousands) 2019 2018 Total revenues $ 1,266,591 $ 848,573 Net loss before tax (252,203) (302,173)

SEGMENT INFORMATION (Tables)

SEGMENT INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Revenue from External Customers by Geographic Areas	The following table summarizes total revenue from customers by geographic region. Product revenues are attributed to countries based on ship-to location. Year Ended December 31, (In thousands) 2020 2019 2018 United States $ 1,413,907 $ 864,849 $ 454,462 Outside of United States 77,484 11,444 — Total revenues $ 1,491,391 $ 876,293 $ 454,462

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Schedule of Income before Income Tax, Domestic and Foreign	Income (loss) before provision for taxes consisted of the following: Year Ended December 31, (In thousands) 2020 2019 2018 Income (loss) before income taxes: Domestic $ (451,067) $ (267,832) $ (175,275) Foreign (406,038) (1,019) 218 Total income (loss) before income taxes $ (857,105) $ (268,851) $ (175,057)
Schedule of expense (benefit) for income taxes	The expense (benefit) for income taxes consists of: Year Ended December 31, (In thousands) 2020 2019 2018 Current expense (benefit): Federal $ (3) $ — $ — State 802 314 92 Foreign 933 (63) — Deferred tax expense (benefit): Federal (6,453) (169,727) — State (3,971) (15,397) — Foreign 120 15 — Total income tax expense (benefit) $ (8,572) $ (184,858) $ 92
Schedule of components of the net deferred tax asset	The components of the net deferred tax asset with the approximate income tax effect of each type of carryforward, credit and temporary differences are as follows: December 31, (In thousands) 2020 2019 Deferred tax assets: Operating loss carryforwards $ 369,642 $ 369,695 Tax credit carryforwards 64,760 51,030 Compensation related differences 48,349 33,378 Lease assets 31,938 30,782 Other temporary differences 6,136 7,049 Tax assets before valuation allowance 520,825 491,934 Less - Valuation allowance (157,629) (120,679) Total deferred tax assets $ 363,196 $ 371,255 Deferred tax liabilities Convertible notes $ (145,925) $ (83,163) Amortization (197,847) (270,421) Property, plant and equipment (4,580) (5,913) Lease liabilities (30,312) (29,586) Other temporary differences (4,078) (2,607) Total deferred tax liabilities (382,742) (391,690) Net deferred tax liabilities $ (19,546) $ (20,435)
Summary of valuation allowance	Activity associated with the Company's valuation allowance is as follows: December 31, (In thousands) 2020 2019 2018 Balance as of January 1, $ (120,679) $ (209,868) $ (214,250) Valuation allowances established (108,944) (132,522) (52,855) Changes to existing valuation allowances 1,662 1,620 (2,744) Acquisition and purchase accounting (5,558) 183,730 (1,739) Additional paid-in-capital 75,890 36,361 61,720 Balance as of December 31, $ (157,629) $ (120,679) $ (209,868)
Schedule of differences between the effective income tax rate and the statutory tax rate	The effective tax rate differs from the statutory tax rate due to the following: December 31, 2020 2019 2018 U.S. Federal statutory rate 21.0 % 21.0 % 21.0 % State taxes 1.9 5.8 3.4 Federal and state tax rate changes — (0.4) — Foreign tax rate differential (1.0) 0.6 — Acquired IPR&D asset expense (9.1) — — Research and development tax credits 1.6 1.1 1.9 Stock-based compensation expense 1.1 22.1 9.1 Non-deductible executive compensation (0.8) (4.1) (4.9) Transaction costs (0.1) (0.7) — Other adjustments (1.0) (0.6) 1.1 Valuation allowance (12.7) 24.0 (31.7) Effective tax rate 0.9 % 68.8 % (0.1) %
Schedule of unrecognized tax benefits	The following is a tabular reconciliation of the amounts of unrecognized tax benefits: December 31, (In thousands) 2020 2019 2018 January 1, $ 10,276 $ 1,926 $ — Increase due to current year tax positions 3,600 2,142 392 Increase due to prior year tax positions 2,753 6,208 1,534 Decrease due to prior year tax positions — — — Settlements — — — December 31, $ 16,629 $ 10,276 $ 1,926

QUARTERLY RESULTS OF OPERATIO_2

QUARTERLY RESULTS OF OPERATIONS (UNAUDITED) (Tables)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Schedule of quarterly statement of operations	The following table sets forth unaudited quarterly statements of operations data for each of the eight quarters ended December 31, 2020 and 2019. In the opinion of management, this information has been prepared on the same basis as the audited consolidated financial statements and contains all adjustments, consisting only of normal recurring adjustments, considered necessary for a fair statement of the unaudited quarterly results for the periods presented. The quarterly data should be read in conjunction with the Company’s audited consolidated financial statements and the notes to the consolidated financial statements appearing elsewhere in this Form 10-K. Quarter Ended (3) March 31, June 30, September 30, December 31, (Amounts in thousands, except per share data) 2020 Revenue $ 347,821 $ 268,868 $ 408,363 $ 466,339 Cost of sales (exclusive of amortization of acquired intangible assets) 81,606 77,892 95,061 99,765 Amortization of acquired intangible assets (1) 20,464 20,555 20,555 20,553 Gross profit 245,751 170,421 292,747 346,021 Operating expenses, net (2) 328,124 237,430 496,082 761,323 Interest income and interest expense (25,056) (20,000) (21,059) (22,971) Income tax benefit 1,732 867 4,510 1,463 Net loss $ (105,697) $ (86,142) $ (219,884) $ (436,810) Net loss per share—basic $ (0.71) $ (0.58) $ (1.46) $ (2.79) Net loss per share—diluted $ (0.71) $ (0.58) $ (1.46) $ (2.79) Weighted average common shares outstanding—basic 148,151 149,727 150,155 156,470 Weighted average common shares outstanding—diluted 148,151 149,727 150,155 156,470 2019 Revenue $ 162,043 $ 199,870 $ 218,805 $ 295,575 Cost of sales (exclusive of amortization of acquired intangible assets) 42,827 51,139 52,335 70,416 Amortization of acquired intangible assets (1) 425 424 424 11,981 Gross profit 118,791 148,307 166,046 213,178 Operating expenses (2) 186,865 182,209 201,772 309,258 Interest income and interest expense (15,335) (5,043) (4,116) (10,575) Income tax benefit (expense) 470 443 (683) 184,628 Net income (loss) $ (82,939) $ (38,502) $ (40,525) $ 77,973 Net income (loss) per share—basic $ (0.66) $ (0.30) $ (0.31) $ 0.56 Net income (loss) per share—diluted $ (0.66) $ (0.30) $ (0.31) $ 0.54 Weighted average common shares outstanding—basic 126,248 129,182 129,567 139,901 Weighted average common shares outstanding—diluted 126,248 129,182 129,567 143,200 _________________________________ (1) Includes only amortization of acquired intangible assets identified as developed technology assets through purchase accounting transactions, which otherwise would have been allocated to cost of sales. (2) Consists of research and development, sales and marketing, general and administrative, and amortization of acquired intangible assets excluding acquired developed technology, which is included in the gross profit calculation above. This also includes intangible asset impairment charges and funding received as part of the CARES Act. Refer to Note 6 for further discussion on the intangible asset impairment charges recorded in the third quarter of 2020. Refer to Note 1 for further discussion on the funding received as part of the CARES Act in the second quarter of 2020.

SUMMARY OF SIGNIFICANT ACCOUN_4

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Use of Estimates (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Apr. 30, 2020	Dec. 31, 2020
Accounting Policies [Abstract]
CARES Act, grant payment received	$ 23.7	$ 23.7

SUMMARY OF SIGNIFICANT ACCOUN_5

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Net Loss Per Share (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Common shares not included in the computation of diluted net loss per share
Antidilutive shares (in shares)	27,284	19,280	20,822
Shares Issued Upon Acquisition
Common shares not included in the computation of diluted net loss per share
Antidilutive shares (in shares)	157	0	0
Employee And Non Employees Stock Option
Common shares not included in the computation of diluted net loss per share
Antidilutive shares (in shares)	2,231	2,700	2,532
Restricted Stock
Common shares not included in the computation of diluted net loss per share
Antidilutive shares (in shares)	3,968	3,801	3,847
Performance Shares
Common shares not included in the computation of diluted net loss per share
Antidilutive shares (in shares)	619	583	2,399
Convertible Notes
Common shares not included in the computation of diluted net loss per share
Antidilutive shares (in shares)	20,309	12,196	12,044

SUMMARY OF SIGNIFICANT ACCOUN_6

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Research and Development Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Research and development	$ 554,052	$ 139,694	$ 67,285
Asset acquisition IPR&D expense	$ 412,568	$ 0	$ 0

SUMMARY OF SIGNIFICANT ACCOUN_7

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Advertising Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Advertising expense	$ 93.2	$ 88.7	$ 93.7

SUMMARY OF SIGNIFICANT ACCOUN_8

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Leases (Details)	12 Months Ended
	Dec. 31, 2020
Lessee, Lease, Description [Line Items]
Operating lease, term extension	10 years
Operating lease, termination period	1 year
Minimum
Lessee, Lease, Description [Line Items]
Operating lease, remaining lease term	1 year
Maximum
Lessee, Lease, Description [Line Items]
Operating lease, remaining lease term	15 years

SUMMARY OF SIGNIFICANT ACCOUN_9

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Concentration of Credit Risk (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Concentration of Credit Risk
Cash, uninsured amount	$ 237
Revenue | Customer Concentration Risk | Centers for Medicare and Medicaid Services
Concentration of Credit Risk
Concentration risk (as a percent)	21.00%	29.00%	36.00%
Revenue | Customer Concentration Risk | UnitedHealthcare
Concentration of Credit Risk
Concentration risk (as a percent)	10.00%	13.00%	13.00%
Revenue | Customer Concentration Risk | State of Wisconsin
Concentration of Credit Risk
Concentration risk (as a percent)	12.00%	0.00%	0.00%
Accounts Receivable | Customer Concentration Risk | Centers for Medicare and Medicaid Services
Concentration of Credit Risk
Concentration risk (as a percent)	14.00%	19.00%	32.00%
Accounts Receivable | Customer Concentration Risk | UnitedHealthcare
Concentration of Credit Risk
Concentration risk (as a percent)	7.00%	7.00%	10.00%
Accounts Receivable | Customer Concentration Risk | State of Wisconsin
Concentration of Credit Risk
Concentration risk (as a percent)	22.00%	0.00%	0.00%

SUMMARY OF SIGNIFICANT ACCOU_10

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Tax Positions (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Valuation allowance
Deferred tax asset valuation allowance	$ 157,629				$ 120,679				$ 157,629	$ 120,679
Change in valuation allowance									36,900	(89,200)
Income tax benefit (expense)	$ 1,463	$ 4,510	$ 867	$ 1,732	$ 184,628	$ (683)	$ 443	$ 470	$ 8,572	$ 184,858	$ (92)

REVENUE - Narrative (Details)

REVENUE - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Deferred revenue	$ 25	$ 0.6
Deferred revenue, revenue recognized during period	0.2	0.2
COVID-19
Disaggregation of Revenue [Line Items]
Deferred revenue	24.2
Variable consideration
Disaggregation of Revenue [Line Items]
Revenue recognized from changes in transaction price	$ 9.6	$ 9.9	$ 15

REVENUE - Schedule of Disaggreg

REVENUE - Schedule of Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Revenue recognized	$ 1,491,391	$ 876,293	$ 454,462
Screening
Disaggregation of Revenue [Line Items]
Revenue recognized	815,067	810,120	454,462
Screening | Medicare Parts B & C
Disaggregation of Revenue [Line Items]
Revenue recognized	365,471	404,331	254,431
Screening | Commercial
Disaggregation of Revenue [Line Items]
Revenue recognized	409,671	368,006	184,538
Screening | Other
Disaggregation of Revenue [Line Items]
Revenue recognized	39,925	37,783	15,493
Precision Oncology
Disaggregation of Revenue [Line Items]
Revenue recognized	440,493	66,173	0
Precision Oncology | Medicare Parts B & C
Disaggregation of Revenue [Line Items]
Revenue recognized	157,166	24,325	0
Precision Oncology | Commercial
Disaggregation of Revenue [Line Items]
Revenue recognized	186,043	29,976	0
Precision Oncology | International
Disaggregation of Revenue [Line Items]
Revenue recognized	77,484	11,444	0
Precision Oncology | Other
Disaggregation of Revenue [Line Items]
Revenue recognized	19,800	428	0
COVID-19 Testing
Disaggregation of Revenue [Line Items]
Revenue recognized	$ 235,831	$ 0	$ 0

MARKETABLE SECURITIES - Narrati

MARKETABLE SECURITIES - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash and Cash Equivalents [Abstract]
Debt security, available for sale, realized gain	$ 0.1	$ 3.4	$ 0.4
Equity securities, realized gain	$ 0.2	$ 0.2	$ 0

MARKETABLE SECURITIES - Schedul

MARKETABLE SECURITIES - Schedule of Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Marketable Securities [Line Items]
Cash and cash equivalents, and restricted cash	$ 1,491,594	$ 177,528
Marketable securities, Fair Value	937,172	175,007
Equity securities	1,521	1,716
Total marketable securities	348,699	146,401
Total cash and cash equivalents, restricted cash and marketable securities	1,840,293	323,929
Cash equivalents
Marketable Securities [Line Items]
Cash and cash equivalents, and restricted cash	589,994
Marketable securities, Fair Value	589,994	30,322
Marketable securities
Marketable Securities [Line Items]
Marketable securities, Fair Value	347,178	144,685
Cash and money market
Marketable Securities [Line Items]
Cash and cash equivalents, and restricted cash	901,294	146,932
Restricted cash
Marketable Securities [Line Items]
Cash and cash equivalents, and restricted cash	$ 306	$ 274

MARKETABLE SECURITIES - Sched_2

MARKETABLE SECURITIES - Schedule of Available For Sale Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Available-for-sale securities
Amortized Cost	$ 936,476	$ 175,082
Gains in Accumulated Other Comprehensive Income (Loss)	696	12
Losses in Accumulated Other Comprehensive Income (Loss)	0	(87)
Estimated Fair Value	937,172	175,007
Cash equivalents
Available-for-sale securities
Amortized Cost	589,986	30,320
Gains in Accumulated Other Comprehensive Income (Loss)	8	2
Losses in Accumulated Other Comprehensive Income (Loss)	0	0
Estimated Fair Value	589,994	30,322
Marketable securities
Available-for-sale securities
Amortized Cost	346,490	144,762
Gains in Accumulated Other Comprehensive Income (Loss)	688	10
Losses in Accumulated Other Comprehensive Income (Loss)	0	(87)
Estimated Fair Value	347,178	144,685
U.S. government agency securities | Cash equivalents
Available-for-sale securities
Amortized Cost	589,986	30,320
Gains in Accumulated Other Comprehensive Income (Loss)	8	2
Losses in Accumulated Other Comprehensive Income (Loss)	0	0
Estimated Fair Value	589,994	30,322
U.S. government agency securities | Marketable securities
Available-for-sale securities
Amortized Cost	207,119	140,745
Gains in Accumulated Other Comprehensive Income (Loss)	52	10
Losses in Accumulated Other Comprehensive Income (Loss)	0	(73)
Estimated Fair Value	207,171	140,682
Corporate bonds | Marketable securities
Available-for-sale securities
Amortized Cost	132,301	4,017
Gains in Accumulated Other Comprehensive Income (Loss)	612	0
Losses in Accumulated Other Comprehensive Income (Loss)	0	(14)
Estimated Fair Value	132,913	$ 4,003
Asset backed securities | Marketable securities
Available-for-sale securities
Amortized Cost	7,070
Gains in Accumulated Other Comprehensive Income (Loss)	24
Losses in Accumulated Other Comprehensive Income (Loss)	0
Estimated Fair Value	$ 7,094

MARKETABLE SECURITIES - Sched_3

MARKETABLE SECURITIES - Schedule of Underlying Maturities of AFS Securities (Details) $ in Thousands	Dec. 31, 2020USD ($)
Available-for-sale securities
Due in one year or less, amortized cost	$ 890,811
Due in one year or less, fair value	891,110
Due after one year through four years, Amortized Cost	45,665
Due after one year through four years, Fair Value	46,062
Cash equivalents
Available-for-sale securities
Due in one year or less, amortized cost	589,986
Due in one year or less, fair value	589,994
Cash equivalents | U.S. government agency securities
Available-for-sale securities
Due in one year or less, amortized cost	589,986
Due in one year or less, fair value	589,994
Marketable securities
Available-for-sale securities
Due in one year or less, amortized cost	300,825
Due in one year or less, fair value	301,116
Due after one year through four years, Amortized Cost	45,665
Due after one year through four years, Fair Value	46,062
Marketable securities | U.S. government agency securities
Available-for-sale securities
Due in one year or less, amortized cost	199,988
Due in one year or less, fair value	199,994
Due after one year through four years, Amortized Cost	7,131
Due after one year through four years, Fair Value	7,177
Marketable securities | Corporate bonds
Available-for-sale securities
Due in one year or less, amortized cost	100,837
Due in one year or less, fair value	101,122
Due after one year through four years, Amortized Cost	31,464
Due after one year through four years, Fair Value	31,791
Marketable securities | Asset backed securities
Available-for-sale securities
Due in one year or less, amortized cost	0
Due in one year or less, fair value	0
Due after one year through four years, Amortized Cost	7,070
Due after one year through four years, Fair Value	$ 7,094

MARKETABLE SECURITIES - Sched_4

MARKETABLE SECURITIES - Schedule of Gross Unrealized Losses And Fair Value of Available For Sale Securities (Details) $ in Thousands	Dec. 31, 2019USD ($)
Marketable Securities [Line Items]
Total fair value of available-for-sale securities in a continuous unrealized loss position for less than twelve months	$ 144,685
Total gross unrealized losses of available-for-sale securities in a continuous unrealized loss position for less than twelve months	(87)
Total fair value of available for sale securities in a continuous unrealized loss position for greater than twelve months	0
Debt securities, available-for-sale, continuous unrealized loss position, 12 months of longer, accumulated loss	0
Total fair value of available-for-sale securities in a continuous unrealized loss position	144,685
Total gross unrealized losses of available-for-sale securities in a continuous unrealized loss position	(87)
Marketable securities | Corporate bonds
Marketable Securities [Line Items]
Total fair value of available-for-sale securities in a continuous unrealized loss position for less than twelve months	4,003
Total gross unrealized losses of available-for-sale securities in a continuous unrealized loss position for less than twelve months	(14)
Total fair value of available for sale securities in a continuous unrealized loss position for greater than twelve months	0
Debt securities, available-for-sale, continuous unrealized loss position, 12 months of longer, accumulated loss	0
Total fair value of available-for-sale securities in a continuous unrealized loss position	4,003
Total gross unrealized losses of available-for-sale securities in a continuous unrealized loss position	(14)
Marketable securities | Asset backed securities
Marketable Securities [Line Items]
Total fair value of available-for-sale securities in a continuous unrealized loss position for less than twelve months	140,682
Total gross unrealized losses of available-for-sale securities in a continuous unrealized loss position for less than twelve months	(73)
Total fair value of available for sale securities in a continuous unrealized loss position for greater than twelve months	0
Debt securities, available-for-sale, continuous unrealized loss position, 12 months of longer, accumulated loss	0
Total fair value of available-for-sale securities in a continuous unrealized loss position	140,682
Total gross unrealized losses of available-for-sale securities in a continuous unrealized loss position	$ (73)

INVENTORY (Details)

INVENTORY (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Inventory Disclosure [Abstract]
Raw materials	$ 43,083	$ 24,958
Semi-finished and finished goods	49,182	36,766
Inventory	$ 92,265	$ 61,724

PROPERTY, PLANT, AND EQUIPMEN_2

PROPERTY, PLANT, AND EQUIPMENT - Schedule of Estimated Useful Lives (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Property, plant and equipment
Property, plant and equipment, gross	$ 587,300	$ 532,956
Accumulated depreciation	(136,617)	(77,631)
Property, plant and equipment, net	450,683	455,325
Land
Property, plant and equipment
Property, plant and equipment, gross	4,466	4,466
Leasehold and building improvements
Property, plant and equipment
Property, plant and equipment, gross	$ 117,865	80,352
Land improvements
Property, plant and equipment
Estimated Useful Life	15 years
Property, plant and equipment, gross	$ 4,864	1,766
Buildings
Property, plant and equipment
Property, plant and equipment, gross	$ 200,980	112,815
Buildings | Minimum
Property, plant and equipment
Estimated Useful Life	30 years
Buildings | Maximum
Property, plant and equipment
Estimated Useful Life	40 years
Computer equipment and computer software
Property, plant and equipment
Estimated Useful Life	3 years
Property, plant and equipment, gross	$ 73,296	65,323
Laboratory equipment
Property, plant and equipment
Property, plant and equipment, gross	$ 142,110	104,008
Laboratory equipment | Minimum
Property, plant and equipment
Estimated Useful Life	3 years
Laboratory equipment | Maximum
Property, plant and equipment
Estimated Useful Life	10 years
Furniture and fixtures
Property, plant and equipment
Property, plant and equipment, gross	$ 24,968	14,539
Furniture and fixtures | Minimum
Property, plant and equipment
Estimated Useful Life	3 years
Furniture and fixtures | Maximum
Property, plant and equipment
Estimated Useful Life	10 years
Assets under construction
Property, plant and equipment
Property, plant and equipment, gross	$ 18,751	$ 149,687

PROPERTY, PLANT, AND EQUIPMEN_3

PROPERTY, PLANT, AND EQUIPMENT - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, plant and equipment
Depreciation	$ 69,400	$ 33,900	$ 20,500
Property, plant and equipment, gross	587,300	532,956
Assets under construction
Property, plant and equipment
Property, plant and equipment, gross	18,751	149,687
Leasehold and building improvements
Property, plant and equipment
Property, plant and equipment, gross	117,865	80,352
Assets under construction	3,200
Laboratory equipment
Property, plant and equipment
Property, plant and equipment, gross	142,110	104,008
Assets under construction	7,600
Software projects
Property, plant and equipment
Assets under construction	7,900
Furniture and fixtures
Property, plant and equipment
Property, plant and equipment, gross	24,968	14,539
Assets under construction	100
Buildings
Property, plant and equipment
Property, plant and equipment, gross	$ 200,980	$ 112,815

INTANGIBLE ASSETS AND GOODWIL_2

INTANGIBLE ASSETS AND GOODWILL - Schedule of Finite Lived Intangible Assets Net Balances and Weighted Average Useful Lives (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	$ 960,133	$ 963,690
Less: Accumulated amortization	(111,810)	(20,411)
Finite-lived intangible assets, net	848,323	943,279
Indefinite-lived intangible assets	103
Finite-lived and indefinite-lived intangible assets, gross	960,236	1,163,961
Finite-lived and indefinite-lived intangible assets, net	$ 848,426	1,143,550
In-process research and development
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets		200,000
Acquired developed technology
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets		$ 271
Trade name
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	14 years 10 months 24 days	15 years 10 months 24 days
Finite-lived intangible assets, gross	$ 100,700	$ 100,700
Less: Accumulated amortization	(7,258)	(961)
Finite-lived intangible assets, net	$ 93,442	$ 99,739
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	12 years 9 months 18 days	13 years 9 months 18 days
Finite-lived intangible assets, gross	$ 2,700	$ 2,700
Less: Accumulated amortization	(404)	(224)
Finite-lived intangible assets, net	$ 2,296	$ 2,476
Patents
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	3 years 8 months 12 days	8 years 9 months 18 days
Finite-lived intangible assets, gross	$ 10,441	$ 22,690
Less: Accumulated amortization	(5,422)	(5,975)
Finite-lived intangible assets, net	$ 5,019	$ 16,715
Service Agreements
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	6 years 6 months	7 years 6 months
Finite-lived intangible assets, gross	$ 30,000	$ 30,000
Less: Accumulated amortization	(4,527)	(571)
Finite-lived intangible assets, net	$ 25,473	$ 29,429
Acquired developed technology
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	9 years	9 years 10 months 24 days
Finite-lived intangible assets, gross	$ 814,171	$ 806,371
Less: Accumulated amortization	(93,278)	(12,344)
Finite-lived intangible assets, net	$ 720,893	$ 794,027
Internally developed technology
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	2 years 2 months 12 days	2 years 6 months
Finite-lived intangible assets, gross	$ 2,121	$ 1,229
Less: Accumulated amortization	(921)	(336)
Finite-lived intangible assets, net	$ 1,200	$ 893

INTANGIBLE ASSETS AND GOODWIL_3

INTANGIBLE ASSETS AND GOODWILL - Schedule of Future Amortization Expense (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
2021	$ 93,401
2022	93,196
2023	92,876
2024	92,422
2025	91,374
Thereafter	385,054
Finite-lived intangible assets, net	$ 848,323	$ 943,279

INTANGIBLE ASSETS AND GOODWIL_4

INTANGIBLE ASSETS AND GOODWILL - Narrative (Details) - USD ($)	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Nov. 08, 2020	Mar. 03, 2020	Nov. 08, 2019
Finite-Lived Intangible Assets [Line Items]
Amortization of acquired intangibles			$ 93,398,000	$ 16,035,000	$ 2,540,000
Intangible asset impairment charge			209,666,000	0	0
Finite-lived intangible assets, gross			960,133,000	963,690,000
Finite-lived intangible assets, accumulated amortization			111,810,000	20,411,000
Goodwill			1,237,672,000	1,203,197,000	17,279,000
Goodwill, impairment loss			0	$ 0	$ 0
Paradigm & Viomics
Finite-Lived Intangible Assets [Line Items]
Goodwill			$ 30,431,000				$ 29,695,000
Genomic Health Inc
Finite-Lived Intangible Assets [Line Items]
Goodwill						$ 1,189,962,000		$ 1,185,918,000
In-process research and development | Armune Biosciences Agreement
Finite-Lived Intangible Assets [Line Items]
Intangible asset impairment charge	$ 9,700,000
Finite-lived intangible assets, gross	12,200,000	$ 12,200,000
Finite-lived intangible assets, accumulated amortization	$ 2,500,000	2,500,000
In-process research and development | Biocartis Agreement
Finite-Lived Intangible Assets [Line Items]
Intangible asset impairment charge		$ 200,000,000

INTANGIBLE ASSETS AND GOODWIL_5

INTANGIBLE ASSETS AND GOODWILL - Schedule of Changes in Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Carrying amount of goodwill
Beginning of the period	$ 1,203,197	$ 17,279
Acquisition	30,431	1,185,918
Genomic Health acquisition adjustment	4,044
Ending of the period	$ 1,237,672	1,203,197
Sampleminded Inc
Carrying amount of goodwill
Beginning of the period		2,000
Biomatrica, Inc
Carrying amount of goodwill
Beginning of the period		$ 15,300

FAIR VALUE MEASUREMENTS - Sched

FAIR VALUE MEASUREMENTS - Schedule of Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Fair value measurements
Cash and cash equivalents, and restricted cash	$ 1,491,594	$ 177,528
Estimated Fair Value	937,172	175,007
Equity securities	1,521	1,716
Restricted cash
Fair value measurements
Cash and cash equivalents, and restricted cash	306	274
Fair Value, Recurring
Fair value measurements
Equity securities	1,521	1,716
Contingent consideration	(2,477)	(2,879)
Total	1,837,816	321,050
Fair Value, Recurring | Corporate bonds
Fair value measurements
Estimated Fair Value	132,913	4,003
Fair Value, Recurring | U.S. government agency securities
Fair value measurements
Estimated Fair Value	207,171	140,682
Fair Value, Recurring | Asset backed securities
Fair value measurements
Estimated Fair Value	7,094
Fair Value, Recurring | Money Market Funds
Fair value measurements
Cash and cash equivalents, and restricted cash	901,294	146,932
Fair Value, Recurring | U.S. government agency securities
Fair value measurements
Cash and cash equivalents, and restricted cash	589,994	30,322
Fair Value, Recurring | Restricted cash
Fair value measurements
Cash and cash equivalents, and restricted cash	306	274
Level 1 | Fair Value, Recurring
Fair value measurements
Equity securities	1,521	1,716
Contingent consideration	0	0
Total	903,121	148,922
Level 1 | Fair Value, Recurring | Corporate bonds
Fair value measurements
Estimated Fair Value	0	0
Level 1 | Fair Value, Recurring | U.S. government agency securities
Fair value measurements
Estimated Fair Value	0	0
Level 1 | Fair Value, Recurring | Asset backed securities
Fair value measurements
Estimated Fair Value	0
Level 1 | Fair Value, Recurring | Money Market Funds
Fair value measurements
Cash and cash equivalents, and restricted cash	901,294	146,932
Level 1 | Fair Value, Recurring | U.S. government agency securities
Fair value measurements
Cash and cash equivalents, and restricted cash	0	0
Level 1 | Fair Value, Recurring | Restricted cash
Fair value measurements
Cash and cash equivalents, and restricted cash	306	274
Level 2 | Fair Value, Recurring
Fair value measurements
Equity securities	0	0
Contingent consideration	0	0
Total	937,172	175,007
Level 2 | Fair Value, Recurring | Corporate bonds
Fair value measurements
Estimated Fair Value	132,913	4,003
Level 2 | Fair Value, Recurring | U.S. government agency securities
Fair value measurements
Estimated Fair Value	207,171	140,682
Level 2 | Fair Value, Recurring | Asset backed securities
Fair value measurements
Estimated Fair Value	7,094
Level 2 | Fair Value, Recurring | Money Market Funds
Fair value measurements
Cash and cash equivalents, and restricted cash	0	0
Level 2 | Fair Value, Recurring | U.S. government agency securities
Fair value measurements
Cash and cash equivalents, and restricted cash	589,994	30,322
Level 2 | Fair Value, Recurring | Restricted cash
Fair value measurements
Cash and cash equivalents, and restricted cash	0	0
Level 3 | Fair Value, Recurring
Fair value measurements
Equity securities	0	0
Contingent consideration	(2,477)	(2,879)
Total	(2,477)	(2,879)
Level 3 | Fair Value, Recurring | Corporate bonds
Fair value measurements
Estimated Fair Value	0	0
Level 3 | Fair Value, Recurring | U.S. government agency securities
Fair value measurements
Estimated Fair Value	0	0
Level 3 | Fair Value, Recurring | Asset backed securities
Fair value measurements
Estimated Fair Value	0
Level 3 | Fair Value, Recurring | Money Market Funds
Fair value measurements
Cash and cash equivalents, and restricted cash	0	0
Level 3 | Fair Value, Recurring | U.S. government agency securities
Fair value measurements
Cash and cash equivalents, and restricted cash	0	0
Level 3 | Fair Value, Recurring | Restricted cash
Fair value measurements
Cash and cash equivalents, and restricted cash	$ 0	$ 0

FAIR VALUE MEASUREMENTS - Narra

FAIR VALUE MEASUREMENTS - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Jul. 31, 2020	Dec. 31, 2019
Foreign Exchange Forward
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative, notional amount	$ 22.4		$ 17.9
Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment owned, fair value	29.1		11.8
Biomatrica, Inc
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Additional contingent consideration liability	20
Epic Sciences
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment owned, fair value	$ 10.8		10.8
Investment owned (in shares)	18,258,838
Thrive
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment owned, fair value	$ 12.5		1
Investment owned (in shares)	5,025,764
Thrive | Series B Preferred Stock
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment owned (in shares)		4,000,000
Non-marketable equity investment		$ 10
Investment income, net	$ 1.5
Thrive | Series A Preferred Stock
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Non-marketable equity investment			$ 1

FAIR VALUE MEASUREMENTS - Fair

FAIR VALUE MEASUREMENTS - Fair Value of Contingent Consideration (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)
Fair Value Disclosures [Abstract]
Beginning balance	$ (2,879)
Changes in fair value	325
Payments	77
Ending balance	$ (2,477)

FAIR VALUE - Long-Term Debt and

FAIR VALUE - Long-Term Debt and Convertible Notes (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Carrying Value | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Construction loan	$ 23,661	$ 24,866
Fair Value | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Construction loan	23,661	24,866
2028 Convertible notes | Carrying Value | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible notes	806,587	0
2028 Convertible notes | Fair Value | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible notes	1,526,625	0
2027 Convertible notes | Carrying Value | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible notes	514,173	483,909
2027 Convertible notes | Fair Value | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible notes	992,306	843,741
2025 Convertible notes | Carrying Value | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible notes	255,464	319,696
2025 Convertible notes | Fair Value | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible notes	$ 601,744	$ 592,482

ACCRUED LIABILITIES (Details)

ACCRUED LIABILITIES (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Payables and Accruals [Abstract]
Compensation	$ 117,273	$ 95,166
Pfizer Promotion Agreement related costs	46,937	33,230
Professional fees	36,113	29,108
Other	20,735	13,976
Assets under construction	2,118	10,720
Research and trial related expenses	5,911	8,368
Licenses	4,517	2,761
Accrued liabilities	$ 233,604	$ 193,329

LONG-TERM DEBT - Construction L

LONG-TERM DEBT - Construction Loan Agreement (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2017	Nov. 30, 2017
Future principal obligations
2021	$ 1,319,000
2022	22,431,000
Total	$ 23,750,000
Construction Loans
Long-term debt
Face amount		$ 25,600,000
Amortization period	20 years
Initial investment	$ 16,400,000
Interest costs capitalized	700,000
Long-term construction loan, current	23,800,000	$ 25,000,000
Debt issuance costs			$ 200,000
Debt instrument, covenant, liquidity required, minimum	$ 250,000,000
Construction Loans | 1-month LIBOR
Long-term debt
Variable rate	2.25%
Interest-only payment, period	24 months
Construction Loans | City Letter of Credit
Long-term debt
Borrowing capacity				$ 600,000

LONG-TERM DEBT - Tax Increment

LONG-TERM DEBT - Tax Increment Financing Loan Agreements (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)position	Dec. 31, 2019USD ($)
Long-term debt
Time frame when amount will be repaid through property taxes	2 years
Tax Increment Financing Loan Agreements
Long-term debt
Face amount	$ 4.6
Number of jobs required to create and maintain | position	500
Term	5 years
Tax Increment Financing Loan Agreements | Short-term other liabilities
Long-term debt
Proceeds from long term debt	$ 0	$ 2.7

CONVERTIBLE DEBT - Schedule of

CONVERTIBLE DEBT - Schedule of Convertible Note Obligations (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Feb. 29, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Convertible notes, net, current portion	$ (255,464)		$ 0
Net long-term convertible debt	$ 1,320,760		803,605
2028 Convertible notes
Debt Instrument [Line Items]
Interest rate (as a percent)	0.375%	0.375%
Effective interest rate (as a percent)	5.20%
Fair value of liability component at issuance	$ 790,608
Convertible notes payable, gross	1,150,000		0
Less: Debt discount	(328,372)		0
Less: Debt issuance costs	(15,041)		0
Unamortized discount	328,372		0
Debt issuance costs	$ 15,041		0
2027 Convertible notes
Debt Instrument [Line Items]
Interest rate (as a percent)	0.375%
Effective interest rate (as a percent)	6.30%
Fair value of liability component at issuance	$ 472,501
Convertible notes payable, gross	747,500		747,500
Less: Debt discount	(224,517)		(253,340)
Less: Debt issuance costs	(8,810)		(10,251)
Unamortized discount	224,517		253,340
Debt issuance costs	$ 8,810		10,251
2025 Convertible notes
Debt Instrument [Line Items]
Interest rate (as a percent)	1.00%
Effective interest rate (as a percent)	6.00%
Fair value of liability component at issuance	$ 227,103
Convertible notes payable, gross	315,049		415,049
Less: Debt discount	(55,796)		(89,123)
Less: Debt issuance costs	(3,789)		(6,230)
Fair value of liability component of 2025 notes	654,800
Carrying amount of equity component of 2025 notes	267,900
Unamortized discount	55,796		89,123
Debt issuance costs	3,789		6,230
Aggregate Convertible Notes
Debt Instrument [Line Items]
Convertible notes payable, gross	2,212,549		1,162,549
Less: Debt discount	(608,685)		(342,463)
Less: Debt issuance costs	(27,640)		(16,481)
Net convertible debt including current maturities	1,576,224		803,605
Convertible notes, net, current portion	(255,464)		0
Net long-term convertible debt	1,320,760		803,605
Unamortized discount	608,685		342,463
Debt issuance costs	$ 27,640		$ 16,481

CONVERTIBLE DEBT - Issuances an

CONVERTIBLE DEBT - Issuances and Settlements (Details) - USD ($) shares in Millions	1 Months Ended				12 Months Ended
	Feb. 29, 2020	Mar. 31, 2019	Jun. 30, 2018	Jan. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Feb. 01, 2020
Debt Instrument [Line Items]
Net proceeds from issuance					$ 1,125,547,000	$ 729,477,000	$ 896,430,000
Value of stock after conversion of convertible notes						182,477,000
Settlement of convertible notes, net of tax					64,199,000	300,768,000	0
Loss on extinguishment of debt	$ 8,000,000				$ 7,954,000	$ 10,558,000	$ 0
2025 Convertible notes
Debt Instrument [Line Items]
Stock issued in conversion of convertible notes (in shares)		2.2
Value of stock after conversion of convertible notes		$ 182,400,000
Repayments of convertible debt in cash and by issuance of shares		676,500,000
Repayments of debt		493,400,000
Consideration settled on liability component of 2025 notes		375,000,000
Settlement of convertible notes, net of tax		300,800,000
Accrued interest on notes		700,000
Loss on extinguishment of debt		10,600,000
2025 Convertible notes
Debt Instrument [Line Items]
Face amount			$ 218,500,000	$ 690,000,000
Interest rate (as a percent)					1.00%
Net proceeds from issuance			$ 225,300,000	$ 671,100,000
Repayments of convertible debt	150,100,000
Consideration settled on liability component of 2025 notes								$ 85,500,000
Settlement of convertible notes, net of tax	64,200,000
Equity component, tax	300,000
Accrued interest on notes	100,000
Debt instrument, Amount Settled In Extinguishment	100,000,000
2027 Convertible notes
Debt Instrument [Line Items]
Face amount		747,500,000
Interest rate (as a percent)					0.375%
Net proceeds from issuance		729,500,000
2027 Convertible notes | 2025 Convertible notes
Debt Instrument [Line Items]
Repayments of convertible debt		$ 494,100,000
2028 Convertible notes
Debt Instrument [Line Items]
Face amount	$ 1,150,000,000
Interest rate (as a percent)	0.375%				0.375%
Net proceeds from issuance	$ 1,130,000,000

CONVERTIBLE DEBT - Summary of C

CONVERTIBLE DEBT - Summary of Conversion Features (Details) $ / shares in Units, $ in Millions	6 Months Ended	12 Months Ended
	Dec. 31, 2019note	Dec. 31, 2020USD ($)$ / shares
Debt Instrument [Line Items]
Repurchase price, as percentage of principal amount, if company undergoes change of control		100
Number of convertible notes converted during period | note	55
Shares issued, price per share (in usd per share)		$ 132.49
2025 Convertible notes
Debt Instrument [Line Items]
Conversion rate, number of shares to be issued per $1,000 of principal amount		13.26
Conversion price per share of common stock		$ 75.43
If-converted value in excess of principal | $		$ 238.3
2027 Convertible notes
Debt Instrument [Line Items]
Conversion rate, number of shares to be issued per $1,000 of principal amount		8.96
Conversion price per share of common stock		$ 111.66
If-converted value in excess of principal | $		$ 139.4
2028 Convertible notes
Debt Instrument [Line Items]
Conversion rate, number of shares to be issued per $1,000 of principal amount		8.21
Conversion price per share of common stock		$ 121.84
If-converted value in excess of principal | $		$ 100.5

CONVERTIBLE DEBT - Ranking of C

CONVERTIBLE DEBT - Ranking of Convertible Notes (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)
January 2025 Notes
Debt Instrument [Line Items]
Transaction costs allocated to liability component	$ 13,569
Transaction costs allocated to equity component	5,340
Total transaction costs	18,909
June 2025 Notes
Debt Instrument [Line Items]
Transaction costs allocated to liability component	5,052
Transaction costs allocated to equity component	2,311
Total transaction costs	7,363
2027 Convertible notes
Debt Instrument [Line Items]
Transaction costs allocated to liability component	11,395
Transaction costs allocated to equity component	6,632
Total transaction costs	18,027
2028 Convertible notes
Debt Instrument [Line Items]
Transaction costs allocated to liability component	16,811
Transaction costs allocated to equity component	7,642
Total transaction costs	$ 24,453

CONVERTIBLE DEBT - Schedule o_2

CONVERTIBLE DEBT - Schedule of Interest Expense (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Feb. 29, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Debt issuance costs amortization		$ 4,207	$ 2,661	$ 2,273
Debt discount amortization		72,272	39,595	26,291
Loss on settlement of convertible notes	$ 8,000	7,954	10,558	0
Coupon interest expense		9,631	7,325	7,823
Total interest expense on convertible notes		94,064	60,139	36,387
Other interest expense		1,919	1,460	402
Interest Expense		$ 95,983	$ 61,599	$ 36,789
2025 Convertible notes
Debt Instrument [Line Items]
Convertible debt, remaining discount amortization period		4 years 14 days
2027 Convertible notes
Debt Instrument [Line Items]
Convertible debt, remaining discount amortization period		6 years 2 months 15 days
2028 Convertible notes
Debt Instrument [Line Items]
Convertible debt, remaining discount amortization period		7 years 2 months 1 day

LICENSE AND COLLABORATION AGR_2

LICENSE AND COLLABORATION AGREEMENTS - Mayo (Details) $ in Thousands	1 Months Ended		12 Months Ended
	Sep. 30, 2020USD ($)installment	Jan. 31, 2016USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Research and development			$ 554,052	$ 139,694	$ 67,285
Licensing Agreements | Mayo
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License fees payable in five annual installments	$ 6,300
Number of annual installments in which license fees are payable | installment	5
License fee payments	$ 1,300
Time period after the last licensed patent expires that the license agreement will remain in effect			5 years
Licensing Agreements | Mayo | Sales Milestone Range One
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Amount agreed to be paid upon reaching the specified amount of net sales		$ 200
Net sales of a licensed product		5,000
Licensing Agreements | Mayo | Sales Milestone Range Two
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Amount agreed to be paid upon reaching the specified amount of net sales		800
Net sales of a licensed product		20,000
Licensing Agreements | Mayo | Sales Milestone Range Three
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Amount agreed to be paid upon reaching the specified amount of net sales		2,000
Net sales of a licensed product		$ 50,000
Licensing Agreements | Mayo
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Research and development			$ 3,900	$ 4,800	$ 4,500

LICENSE AND COLLABORATION AGR_3

LICENSE AND COLLABORATION AGREEMENTS - Epic Sciences (Details)	12 Months Ended
	Dec. 31, 2020
Licensing Agreements | Epic Sciences
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Term of agreement	10 years

LICENSE AND COLLABORATION AGR_4

LICENSE AND COLLABORATION AGREEMENTS - Biocartis (Details) - Biocartis N.V. - USD ($) $ in Millions	1 Months Ended
	Oct. 31, 2020	Dec. 31, 2020	Dec. 31, 2018	Sep. 30, 2018
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Investment owned (in shares)			270,000
Investment owned, fair value		$ 1.5	$ 4
Licensing Agreements
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
One-time fee for a royalty-free, fully-paid, perpetual and assignable license to patents				$ 3.2
Early contract termination payment	$ 12

PFIZER PROMOTION AGREEMENT (Det

PFIZER PROMOTION AGREEMENT (Details) - Pfizer Inc - Manufactured Product, Other - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Charges for promotion, sales and marketing	$ 85.3	$ 68.9	$ 5.8
Service fee based on incremental gross profits over specified baselines and royalties	$ 51.2	$ 68.5	$ 4.8

STOCKHOLDERS' EQUITY - Narrativ

STOCKHOLDERS' EQUITY - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	Nov. 08, 2019	Oct. 31, 2020	Mar. 31, 2020	Nov. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jul. 01, 2020	Jun. 30, 2020
Subsidiary or Equity Method Investee [Line Items]
Common stock, authorized shares (in shares)						400,000,000	400,000,000	400,000,000		400,000,000	200,000,000
Value of stock after conversion of convertible notes								$ 182,477
Business combination, consideration transferred	$ 2,470,000
Stock issued during period, value, acquisitions							$ 28,847	$ 1,407,080	$ 0
Issuance of common stock to fund business combinations (in shares)			400,000	17,000,000			386,293	17,046,159
Issuance of common stock, issuance costs				$ 400				$ 441
Sale of stock, number of shares issued in transaction (in shares)		8,600,000
Sale of stock, price per share (in usd per share)		$ 101
Sale of stock, consideration received on transaction		$ 861,700
Underwriting discount and other stock issuance costs		$ 7,500
Genomic Health Inc
Subsidiary or Equity Method Investee [Line Items]
Business combination, consideration transferred	2,468,568			2,470,000
Stock issued during period, value, acquisitions	$ 1,389,266			$ 1,410,000
Paradigm & Viomics
Subsidiary or Equity Method Investee [Line Items]
Business combination, consideration transferred			$ 40,400
Stock issued during period, value, acquisitions			$ 32,200
Issuance of common stock to acquire business						$ 28,800
2025 Convertible notes
Subsidiary or Equity Method Investee [Line Items]
Settlement of convertible notes (in shares)					2,200,000
Value of stock after conversion of convertible notes					$ 182,400
Repayments of convertible debt in cash and by issuance of shares					676,500
Repayments of debt					493,400
2027 Convertible notes | 2025 Convertible notes
Subsidiary or Equity Method Investee [Line Items]
Repayments of debt in cash					$ 494,100

STOCKHOLDERS' EQUITY - Schedule

STOCKHOLDERS' EQUITY - Schedule of OCI (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 2,288,061	$ 680,941	$ 520,418
Other comprehensive income (loss) before reclassifications	771	681	(989)
Amounts reclassified from accumulated other comprehensive loss	25	641	317
Net current period change in accumulated other comprehensive income (loss)	796	1,322	(672)
Income tax expense related to items of other comprehensive income	(170)
Ending balance	2,823,489	2,288,061	680,941
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(100)	(1,422)	(750)
Ending balance	526	(100)	(1,422)
Cumulative Translation Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(25)	(25)	(61)
Other comprehensive income (loss) before reclassifications	0	0	36
Amounts reclassified from accumulated other comprehensive loss	25	0	0
Net current period change in accumulated other comprehensive income (loss)	25	0	36
Income tax expense related to items of other comprehensive income	0
Ending balance	0	(25)	(25)
Unrealized Gain (Loss) on Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(75)	(1,397)	(689)
Other comprehensive income (loss) before reclassifications	771	681	(1,025)
Amounts reclassified from accumulated other comprehensive loss	0	641	317
Net current period change in accumulated other comprehensive income (loss)	771	1,322	(708)
Income tax expense related to items of other comprehensive income	(170)
Ending balance	$ 526	$ (75)	$ (1,397)

STOCKHOLDERS' EQUITY - Schedu_2

STOCKHOLDERS' EQUITY - Schedule of amounts reclassified from AOCI (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Changes in Accumulated Other Comprehensive Income (Loss)
General and administrative	$ (481,716)	$ (352,453)	$ (178,016)
Total reclassifications	25	641	317
Reclassification Out Of Accumulated Other Comprehensive Income | Unrealized Gain (Loss) on Securities
Changes in Accumulated Other Comprehensive Income (Loss)
Investment income, net	0	641	317
Reclassification Out Of Accumulated Other Comprehensive Income | Cumulative Translation Adjustment
Changes in Accumulated Other Comprehensive Income (Loss)
General and administrative	$ 25	$ 0	$ 0

STOCK-BASED COMPENSATION - Stoc

STOCK-BASED COMPENSATION - Stock-Based Compensation Plans (Details)	Nov. 02, 2020$ / sharesshares	Apr. 30, 2020$ / sharesshares	Jul. 28, 2016shares	Jul. 24, 2014shares	Dec. 31, 2020USD ($)itemshares	Dec. 31, 2019shares	Dec. 31, 2018shares	Dec. 31, 2020shares
Stock-based compensation
Shares outstanding (in shares)					2,231,059	2,700,293		2,231,059
Shares available for future grant (in shares)					12,657,752			12,657,752
Stock Option And Incentive Plan 2000
Stock-based compensation
Further grants or awards after termination of plan (in shares)					0
Period by which all options to purchase common stock will accelerate upon an acquisition of the company					1 year
Stock Option And Incentive Plan 2000 | Employee And Non Employees Stock Option
Stock-based compensation
Expiration period from the date of grant					10 years
Shares outstanding (in shares)					0			0
Stock Option And Incentive Plan 2000 | Employee And Non Employees Stock Option | Minimum
Stock-based compensation
Vesting period					3 years
Stock Option And Incentive Plan 2000 | Employee And Non Employees Stock Option | Maximum
Stock-based compensation
Vesting period					4 years
Stock Option And Incentive Plan 2000 | Restricted Stock
Stock-based compensation
Shares outstanding (in shares)					0			0
Omnibus Long Term Incentive Plan 2010
Stock-based compensation
Further grants or awards after termination of plan (in shares)					0
Shares available for future grant (in shares)					0			0
Omnibus Long Term Incentive Plan 2010 | Minimum
Stock-based compensation
Vesting period					3 years
Omnibus Long Term Incentive Plan 2010 | Maximum
Stock-based compensation
Vesting period					4 years
Omnibus Long Term Incentive Plan 2010 | Employee And Non Employees Stock Option
Stock-based compensation
Expiration period from the date of grant					10 years
Shares outstanding (in shares)					1,763,865			1,763,865
Omnibus Long Term Incentive Plan 2010 | Restricted Stock
Stock-based compensation
Shares outstanding (in shares)					2,138,282			2,138,282
Omnibus Long Term Incentive Plan 2019
Stock-based compensation
Shares available for future grant (in shares)					11,898,737			11,898,737
Omnibus Long Term Incentive Plan 2019 | Minimum
Stock-based compensation
Vesting period					3 years
Omnibus Long Term Incentive Plan 2019 | Maximum
Stock-based compensation
Vesting period					4 years
Omnibus Long Term Incentive Plan 2019 | Employee And Non Employees Stock Option
Stock-based compensation
Expiration period from the date of grant					10 years
Shares outstanding (in shares)					467,194			467,194
Omnibus Long Term Incentive Plan 2019 | Restricted Stock
Stock-based compensation
Shares outstanding (in shares)					2,388,415			2,388,415
Employee Stock Purchase Plan 2010
Stock-based compensation
Shares available for future grant (in shares)					759,015			759,015
Increase in number of shares reserved for issuance			2,000,000	500,000
Option exercise price, expressed as a percentage of fair market value					85.00%
Maximum value of shares that an employee is permitted to purchase | $					$ 25,000
Number of Shares (in shares)					301,064			2,040,985
Employee Stock Purchase Plan 2010 | Offering Period End Date One
Stock-based compensation
Number of Shares (in shares)		167,921
Weighted average price per share (in dollars per share) | $ / shares		$ 57.95
Employee Stock Purchase Plan 2010 | Offering Period End Date Two
Stock-based compensation
Number of Shares (in shares)	133,143
Weighted average price per share (in dollars per share) | $ / shares	$ 64.35
Employee Stock Purchase Plan 2010 | Minimum
Stock-based compensation
Number of hours per week of customary employment required to participate in the plan | item					20
Number of months of customary employment required to participate in the plan					5 months
Percentage of employee's compensation to be deducted from the employee's pay					1.00%
Employee Stock Purchase Plan 2010 | Maximum
Stock-based compensation
Percentage of employee's compensation to be deducted from the employee's pay					15.00%
Employee Stock Purchase Plan 2010 | Employee Stock
Stock-based compensation
Number of Shares (in shares)					301,064	176,458	346,609
2016 Inducement Award Plan
Stock-based compensation
Further grants or awards after termination of plan (in shares)					0
Expiration period from the date of grant					10 years
Shares available for future grant (in shares)					0			0
2016 Inducement Award Plan | Minimum
Stock-based compensation
Vesting period					3 years
2016 Inducement Award Plan | Maximum
Stock-based compensation
Vesting period					4 years
2016 Inducement Award Plan | Restricted Stock
Stock-based compensation
Shares outstanding (in shares)					60,032			60,032

STOCK-BASED COMPENSATION - St_2

STOCK-BASED COMPENSATION - Stock-Based Compensation Expense (Details) $ in Thousands	Apr. 25, 2018shares	Dec. 31, 2020USD ($)employeesshares	Dec. 31, 2019USD ($)shares	Dec. 31, 2018USD ($)
Stock-based compensation expense
Stock-based compensation expense		$ 152,906	$ 108,483	$ 60,264
Non-cash stock-based compensation expense				3,900
Number of employees impacted by change in operational milestones | employees		36
Employee And Non Employees Stock Option
Stock-based compensation expense
Accelerated vesting (in shares) | shares	69,950
Employee And Non Employees Stock Option | Genomic Health Inc
Stock-based compensation expense
Accelerated vesting (in shares) | shares		83,593	364,281
Restricted Shares and RSUs
Stock-based compensation expense
Accelerated vesting (in shares) | shares	54,350
Restricted Shares and RSUs | Genomic Health Inc
Stock-based compensation expense
Non-cash stock-based compensation expense		$ 9,700	$ 21,600
Accelerated vesting (in shares) | shares		93,770	70,138
Cost of sales
Stock-based compensation expense
Stock-based compensation expense		$ 12,852	$ 5,799	3,531
Research and Development Expense
Stock-based compensation expense
Stock-based compensation expense		19,976	17,196	10,189
General and Administrative Expense
Stock-based compensation expense
Stock-based compensation expense		75,999	64,222	34,181
Selling and Marketing Expense
Stock-based compensation expense
Stock-based compensation expense		$ 44,079	$ 21,266	$ 12,363

STOCK-BASED COMPENSATION - Sche

STOCK-BASED COMPENSATION - Schedule of Fair Value of Options and ESPP (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Employee And Non Employees Stock Option
Valuation assumptions
Risk-free interest rates, minimum	1.26%	2.54%	2.73%
Risk-free interest rates, maximum	1.47%	2.59%	2.79%
Expected term		6 years 3 months 10 days
Expected volatility, minimum (as a percent)	65.67%	64.95%	61.82%
Expected volatility, maximum (as a percent)	65.71%	64.99%	66.17%
Dividend yield	0.00%	0.00%	0.00%
Weighted average fair value per share of options granted during the period (in dollars per share)	$ 58.57	$ 57.11	$ 24.55
Employee Stock
Valuation assumptions
Risk-free interest rates, minimum	0.11%	1.60%	2.10%
Risk-free interest rates, maximum	0.20%	2.40%	2.80%
Expected volatility, minimum (as a percent)	61.59%	43.20%	51.70%
Expected volatility, maximum (as a percent)	89.00%	57.60%	65.40%
Dividend yield	0.00%	0.00%	0.00%
Minimum | Employee And Non Employees Stock Option
Valuation assumptions
Expected term			5 years 5 months 12 days
Minimum | Employee Stock
Valuation assumptions
Expected term	6 months	4 months 24 days	6 months
Maximum | Employee And Non Employees Stock Option
Valuation assumptions
Expected term	6 years 1 month 24 days		6 years 5 months 8 days
Maximum | Employee Stock
Valuation assumptions
Expected term	2 years	2 years	2 years

STOCK-BASED COMPENSATION - St_3

STOCK-BASED COMPENSATION - Stock Option, Restricted Stock, and Performance Shares (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended			126 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020
Stock-based compensation
Unrecognized compensation cost	$ 262,500			$ 262,500
Weighted average period for recognition of unrecognized compensation cost	2 years 7 months 17 days
Proceeds from stock option exercises	$ 27,100	$ 8,800	$ 6,600
Shares
Outstanding at the beginning of the period (in shares)	2,700,293
Granted (in shares)	309,143
Exercised (in shares)	(707,013)
Forfeited (in shares)	(71,364)
Outstanding at the end of the period (in shares)	2,231,059	2,700,293		2,231,059
Vested and expected to vest (in shares)	2,231,059			2,231,059
Exercisable at the end of the period (in shares)	1,399,721			1,399,721
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)	$ 34.01
Granted (in dollars per share)	97.66
Exercised (in dollars per share)	39.07
Forfeited (in dollars per share)	82.76
Outstanding at the end of the period (in dollars per share)	39.67	$ 34.01		$ 39.67
Vested and expected to vest (in dollars per share)	39.67			39.67
Exercisable at the end of the period (in dollars per share)	$ 22.53			$ 22.53
Weighted Average Remaining Contractual Term
Outstanding at the end of the period	6 years	6 years 8 months 12 days
Vested and expected to vest at end of period	6 years
Exercisable at the end of the period	4 years 10 months 24 days
Aggregate Intrinsic Value
Outstanding at the end of the period	$ 207,090			$ 207,090
Vested and expected to vest at the end of the period	207,090			207,090
Exercisable at the end of the period	153,912			$ 153,912
Additional disclosures
Total intrinsic value of options exercised	$ 40,600	$ 52,000	$ 53,000
Weighted Average Grant Date Fair Value
Performance share units, percentage earned, minimum	0.00%
Performance share units, percentage earned, maximum	200.00%
Restricted Shares and RSUs
Restricted Shares and Performance Shares
Outstanding at the beginning of the period (in shares)	3,800,722
Granted (in shares)	2,236,535
Released (in shares)	(1,731,631)
Forfeited (in shares)	(337,412)
Outstanding at the end of the period (in shares)	3,968,214	3,800,722		3,968,214
Weighted Average Grant Date Fair Value
Outstanding at the beginning of the period (in dollars per share)	$ 58.68
Granted (in dollars per share)	92.55	$ 93.20	$ 50.45
Released (in dollars per share)	50.67
Forfeited (in dollars per share)	81.36
Outstanding at the end of the period (in dollars per share)	$ 79.38	$ 58.68		$ 79.38
Fair value of equity instruments other than options	$ 152,400	$ 173,800	$ 63,800
Performance Shares
Restricted Shares and Performance Shares
Outstanding at the beginning of the period (in shares)	583,283
Granted (in shares)	35,232
Released (in shares)	0
Forfeited (in shares)	0
Outstanding at the end of the period (in shares)	618,515	583,283		618,515
Weighted Average Grant Date Fair Value
Outstanding at the beginning of the period (in dollars per share)	$ 93.40
Granted (in dollars per share)	90.17	$ 93.40
Released (in dollars per share)	0
Forfeited (in dollars per share)	0
Outstanding at the end of the period (in dollars per share)	$ 93.22	$ 93.40		$ 93.22
Number of outstanding performance share units (in shares)	158,958			158,958
Fair value of equity instruments other than options	$ 0	$ 183,800	$ 0
Employee Stock Purchase Plan 2010
Stock-based compensation
Stock issued under the Company's stock purchase plan (in shares)	301,064			2,040,985

STOCK-BASED COMPENSATION - Sc_2

STOCK-BASED COMPENSATION - Schedule of Share Issued During Period (Details) - Employee Stock Purchase Plan 2010 - $ / shares	Nov. 02, 2020	Apr. 30, 2020	Dec. 31, 2020	Dec. 31, 2020
Stock-based compensation
Stock issued under the Company's stock purchase plan (in shares)			301,064	2,040,985
Offering Period End Date One
Stock-based compensation
Stock issued under the Company's stock purchase plan (in shares)		167,921
Weighted average price per share (in dollars per share)		$ 57.95
Offering Period End Date Two
Stock-based compensation
Stock issued under the Company's stock purchase plan (in shares)	133,143
Weighted average price per share (in dollars per share)	$ 64.35

STOCK-BASED COMPENSATION - Issu

STOCK-BASED COMPENSATION - Issuance of Stock Under ESPP (Details) - Employee Stock Purchase Plan 2010 - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended			126 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020
Stock-based compensation
Stock issued under the Company's stock purchase plan (in shares)	301,064			2,040,985
Employee Stock
Stock-based compensation
Stock issued under the Company's stock purchase plan (in shares)	301,064	176,458	346,609
Cash received under the 2010 Purchase Plan	$ 18,355	$ 8,396	$ 4,895
Weighted average fair value per share of options granted during the period (in dollars per share)	$ 32.57	$ 29.21	$ 20.47

STOCK-BASED COMPENSATION - Shar

STOCK-BASED COMPENSATION - Shares Reserved for Issuance (Details)	Dec. 31, 2020shares
Shares reserved for issuance
Shares reserved for issuance (in shares)	12,657,752
Employee Stock Purchase Plan 2019
Shares reserved for issuance
Shares reserved for issuance (in shares)	11,898,737
Employee Stock Purchase Plan 2010
Shares reserved for issuance
Shares reserved for issuance (in shares)	759,015

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - Lease Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Finance lease cost
Amortization of right-of-use assets	$ 1,935	$ 27
Interest on lease liabilities	383	2
Operating lease cost	22,551	9,200
Short-term lease cost	356	219
Variable lease cost	2,703	896
Total Lease Cost	$ 27,928	$ 10,344

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES - Supplemental Disclosure of Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 17,531	$ 9,641
Operating cash flows from finance leases	381	1
Finance cash flows from finance leases	1,756	15
Non-cash investing and financing activities:
Right-of-use assets obtained in exchange for new operating lease liabilities	13,261	51,030
Right-of-use assets obtained in exchange for new finance lease liabilities	$ 20,349	$ 237
Weighted-average remaining lease term - operating leases (in years)	8 years 9 months	9 years 9 months 18 days
Weighted-average remaining lease term - finance leases (in years)	3 years 8 months 4 days	1 year 2 months 12 days
Weighted-average discount rate - operating leases	6.80%	6.80%
Weighted-average discount rate - finance leases	5.67%	5.60%
ASU 2016-02
Non-cash investing and financing activities:
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 17,900

COMMITMENTS AND CONTINGENCIES_3

COMMITMENTS AND CONTINGENCIES - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Recognition of ROU assets		$ 125,947	$ 126,444
Recognition of lease liabilities		132,558	126,600
Operating lease liability, current		11,483	7,891
Operating lease liability, noncurrent		121,075	118,665
Finance lease, right-of-use asset		20,600	300
Finance lease obligations		18,745	200
Finance lease liability, current		4,700	32
Finance lease liability, noncurrent		14,000	$ 200
Lease not yet commenced, liability		8,300
Lease not yet commenced, asset		$ 8,200
Operating Leases, Rent Expense	$ 3,600
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]		us-gaap:OtherLiabilitiesNoncurrent	us-gaap:OtherLiabilitiesNoncurrent
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]		us-gaap:OtherAssetsNoncurrent	us-gaap:OtherAssetsNoncurrent
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]		us-gaap:OtherLiabilitiesCurrent	us-gaap:OtherLiabilitiesCurrent

COMMITMENTS AND CONTINGENCIES_4

COMMITMENTS AND CONTINGENCIES - Schedule of Maturities on Operating Lease Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2021	$ 19,881
2022	19,596
2023	21,306
2024	21,257
2025	19,338
Thereafter	79,141
Total minimum lease payments	180,519
Imputed interest	(47,961)
Total	$ 132,558	$ 126,600

COMMITMENTS AND CONTINGENCIES_5

COMMITMENTS AND CONTINGENCIES - Schedule of Maturities on Finance Lease Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Finance Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2021	$ 5,674
2022	5,635
2023	5,525
2024	3,819
2025	53
Thereafter	0
Total minimum lease payments	20,706
Imputed interest	(1,961)
Total	$ 18,745	$ 200

EMPLOYEE BENEFIT PLAN (Details)

EMPLOYEE BENEFIT PLAN (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Retirement Benefits [Abstract]
Matching contribution by employer	100.00%	100.00%	100.00%
Percentage of participant's salary matched by employer	6.00%	6.00%	6.00%
Compensation expense in connection with the 401 (k) Plan	$ 22.8	$ 12.5	$ 7.4

NEW MARKET TAX CREDIT (Details)

NEW MARKET TAX CREDIT (Details) - New Market Tax Credit Program $ in Millions	3 Months Ended
	Dec. 31, 2014USD ($)facility
Disclosures related to New Market Tax Credit
Net proceeds received from financing arrangements | $	$ 2.4
Number of facilities receiving working capital and capital improvements from financing agreements | facility	1

WISCONSIN ECONOMIC DEVELOPMEN_2

WISCONSIN ECONOMIC DEVELOPMENT TAX CREDIT (Details) - Wisconsin Economic Development Tax Credit Agreement $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)position	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Agreements
Refundable tax credits earned	$ 9
Capital investment expenditures over specified period, requirement to earn the refundable tax credits	$ 26.3
Full-time positions that must be created over a specified time period to earn the refundable tax credits | position	758
Period over which the capital investment expenditures must be incurred and the creation of full-time positions must be completed	7 years
Refundable tax credit received	$ 5.9
Refundable tax credit receivable	3.1
Amortization of tax credits	2.2	$ 2.4	$ 2.2
Prepaid expenses and other current assets
Agreements
Refundable tax credit receivable	1.6
Other long-term assets
Agreements
Refundable tax credit receivable	1.5
Short-term other liabilities
Agreements
Refundable tax credit, offsetting liability	$ 0

BUSINESS COMBINATIONS AND ASS_2

BUSINESS COMBINATIONS AND ASSET ACQUISITIONS - Business Combinations Narrative (Details) $ in Thousands	Mar. 03, 2020USD ($)	Nov. 08, 2019USD ($)	Mar. 31, 2020USD ($)	Nov. 30, 2019USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2020USD ($)country	Dec. 31, 2020USD ($)country	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Nov. 08, 2020USD ($)
Acquisition
Business combination, consideration transferred		$ 2,470,000
Consideration transferred, net of cash acquired							$ 6,658	$ 973,861	$ 17,908
Equity interests issued or issuable to previous investors	$ 8,400
Weighted average period for recognition of unrecognized compensation cost							2 years 7 months 17 days
Number of countries in which entity operates | country						90	90
Acquired developed technology
Acquisition
Developed technology useful life (in years)							9 years	9 years 10 months 24 days
Trade name
Acquisition
Developed technology useful life (in years)							14 years 10 months 24 days	15 years 10 months 24 days
Paradigm & Viomics
Acquisition
Business combination, consideration transferred			$ 40,400
Consideration transferred, net of cash acquired			$ 8,200
Issuance of common stock to acquire business						$ 28,800
Amount of shares held for future issuance						3,400	$ 3,400
Equity interests issued or issuable to previous investors, vesting period	4 years
Intangible assets	$ 7,800					$ 7,800	7,800
Paradigm & Viomics | Acquired developed technology
Acquisition
Developed technology useful life (in years)	15 years
Genomic Health Inc
Acquisition
Business combination, consideration transferred		$ 2,468,568		$ 2,470,000
Acquisition related costs							$ 22,500
Share conversion ratio		0.76534
Severance benefits expense					$ 32,100
Genomic Health Inc | Options
Acquisition
Total consideration of stock options and restricted stock awards		$ 34,300
Amount allocated to purchase consideration of stock options and restricted stock awards		2,200
Share based compensation, costs not yet recognized		$ 32,100
Weighted average period for recognition of unrecognized compensation cost		1 year 8 months 8 days
Genomic Health Inc | Restricted Stock
Acquisition
Total consideration of stock options and restricted stock awards		$ 42,300
Amount allocated to purchase consideration of stock options and restricted stock awards		15,600
Share based compensation, costs not yet recognized		$ 26,700
Weighted average period for recognition of unrecognized compensation cost		2 years 1 month 13 days
Genomic Health Inc | Acquired developed technology
Acquisition
Developed technology useful life (in years)		10 years
Intangible assets		$ 800,000								$ 800,000
Genomic Health Inc | Trade name
Acquisition
Developed technology useful life (in years)		16 years
Intangible assets		$ 100,000								100,000
Genomic Health Inc | In-process research and development
Acquisition
Intangible assets		$ 200,000								$ 200,000

BUSINESS COMBINATIONS AND ASS_3

BUSINESS COMBINATIONS AND ASSET ACQUISITIONS - Schedule of Assets Acquired and Liabilities Assumed From Paradigm Diagnostics Acquisition (Details) - USD ($) $ in Thousands	10 Months Ended
	Dec. 31, 2020	Mar. 03, 2020	Dec. 31, 2019	Dec. 31, 2018
Acquisition
Goodwill	$ 1,237,672		$ 1,203,197	$ 17,279
Paradigm & Viomics
Acquisition
Net operating assets	5,373	$ 6,133
Goodwill	30,431	29,695
Intangible assets	7,800	7,800
Net operating liabilities	(3,203)	(3,123)
Net assets acquired	40,401	$ 40,505
Measurement Period Adjustments
Net operating assets	(760)
Goodwill	736
Developed technology	0
Net operating liabilities	(80)
Total purchase price	$ (104)

BUSINESS COMBINATIONS AND ASS_4

BUSINESS COMBINATIONS AND ASSET ACQUISITIONS - Business Combination Transferred for Genomic Health (Details) - USD ($) $ in Thousands	Nov. 08, 2019	Nov. 30, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Acquisition
Stock issued during period, value, acquisitions			$ 28,847	$ 1,407,080	$ 0
Total purchase price	$ 2,470,000
Genomic Health Inc
Acquisition
Cash investment	1,061,489
Stock issued during period, value, acquisitions	1,389,266	$ 1,410,000
Aggregate purchase price	17,813
Total purchase price	$ 2,468,568	$ 2,470,000

BUSINESS COMBINATIONS AND ASS_5

BUSINESS COMBINATIONS AND ASSET ACQUISITIONS - Assumptions on Fair Value of Options Assumed (Details) - Options	12 Months Ended
	Dec. 31, 2019$ / shares
Acquisition
Risk-free interest rates, minimum	0.88%
Risk-free interest rates, maximum	2.90%
Expected volatility, minimum (as a percent)	63.54%
Expected volatility, maximum (as a percent)	69.09%
Dividend yield	0.00%
Minimum
Acquisition
Expected term	3 years 3 months 10 days
Weighted average fair value per share of options granted during the period (in dollars per share)	$ 45.75
Maximum
Acquisition
Expected term	6 years 8 months 23 days
Weighted average fair value per share of options granted during the period (in dollars per share)	$ 57.44

BUSINESS COMBINATIONS AND ASS_6

BUSINESS COMBINATIONS AND ASSET ACQUISITIONS - Business Combinations Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	12 Months Ended
	Nov. 08, 2020	Dec. 31, 2020	Dec. 31, 2019	Nov. 08, 2019	Dec. 31, 2018
Acquisition
Goodwill		$ 1,237,672	$ 1,203,197		$ 17,279
Genomic Health Inc
Acquisition
Cash and cash equivalents	$ 87,627			$ 87,627
Marketable securities	201,519			201,519
Accounts receivable	57,400			57,400
Inventory	3,535			3,535
Prepaid expenses and other current assets	8,360			8,360
Property, plant and equipment	69,783			69,905
Goodwill	1,189,962			1,185,918
Operating lease right-of-use assets	80,790			80,790
Other long-term assets	14,876			14,972
Accounts payable, accrued liabilities and other current liabilities	(88,447)			(88,995)
Deferred tax liability	(209,910)			(205,536)
Operating lease liabilities, current portion	(3,258)			(3,258)
Operating lease liabilities, less current portion	(71,270)			(71,270)
Other long-term liabilities	(2,399)			(2,399)
Total fair value consideration	2,468,568			2,468,568
Measurement Period Adjustments
Property, plant and equipment	(122)
Goodwill	4,044
Other long-term assets	(96)
Accounts payable, accrued liabilities and other current liabilities	548
Deferred tax liability	(4,374)
Total purchase price	0
Genomic Health Inc | Trade name
Acquisition
Intangible assets	100,000			100,000
Genomic Health Inc | Supply Agreement
Acquisition
Intangible assets	30,000			30,000
Genomic Health Inc | Acquired developed technology
Acquisition
Intangible assets	800,000			800,000
Genomic Health Inc | In-process research and development
Acquisition
Intangible assets	$ 200,000			$ 200,000

BUSINESS COMBINATIONS AND ASS_7

BUSINESS COMBINATIONS AND ASSET ACQUISITIONS - Proforma Information (Details) - Genomic Health Inc - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Acquisition
Total revenues	$ 435,960	$ 66,174
Net loss before tax	$ (254,162)	(40,446)
Total revenues		1,266,591	$ 848,573
Net loss before tax		$ (252,203)	$ (302,173)

BUSINESS COMBINATIONS AND ASS_8

BUSINESS COMBINATIONS AND ASSET ACQUISITIONS - Asset Acquisition Narrative (Details) - USD ($) $ in Thousands	Oct. 26, 2020	Dec. 31, 2020
Business Combinations [Abstract]
Cash paid for acquisition of Base Genomics outstanding shares	$ 416,525
Transaction costs	$ 4,600	$ 4,600

BUSINESS COMBINATIONS AND ASS_9

BUSINESS COMBINATIONS AND ASSET ACQUISITIONS - Asset Acquisitions and Liabilities Assumed (Details) - USD ($) $ in Thousands	Oct. 26, 2020	Dec. 31, 2020
Business Combinations [Abstract]
Cash paid for acquisition of Base Genomics outstanding shares	$ 416,525
Transaction costs	4,600	$ 4,600
Total consideration	421,125
Cash	9,704
IPR&D asset	412,568
Other assets and liabilities	(1,147)
Net assets acquired	$ 421,125

SEGMENT INFORMATION (Details)

SEGMENT INFORMATION (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Revenue	$ 466,339	$ 408,363	$ 268,868	$ 347,821	$ 295,575	$ 218,805	$ 199,870	$ 162,043	$ 1,491,391	$ 876,293	$ 454,462
United States
Segment Reporting Information [Line Items]
Revenue									1,413,907	864,849	454,462
Outside of United States
Segment Reporting Information [Line Items]
Revenue									$ 77,484	$ 11,444	$ 0

INCOME TAXES - Income (Loss) Be

INCOME TAXES - Income (Loss) Before Income Taxes, Domestic and Foreign (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Domestic	$ (451,067)	$ (267,832)	$ (175,275)
Foreign	(406,038)	(1,019)	218
Net loss before tax	$ (857,105)	$ (268,851)	$ (175,057)

INCOME TAXES - Additional Infor

INCOME TAXES - Additional Information (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
Income tax benefit (expense)	$ 1,463,000	$ 4,510,000	$ 867,000	$ 1,732,000	$ 184,628,000	$ (683,000)	$ 443,000	$ 470,000	$ 8,572,000	$ 184,858,000	$ (92,000)
Deferred tax asset valuation allowance												$ 157,629,000	$ 120,679,000
Deferred tax liability												19,546,000	20,435,000
Change in valuation allowance									36,900,000	(89,200,000)
Unrecognized tax benefit that would impact effective tax rate												16,600,000	10,300,000	$ 1,900,000
Unrecognized tax benefits	16,629,000			10,276,000	10,276,000			1,926,000	16,629,000	1,926,000	0	16,629,000	10,276,000	1,926,000
Recognized interest or penalties									0	0	0
Accrued interest or penalties												0	0	$ 0
Expense (benefit) for income taxes
Total income tax expense (benefit)	(1,463,000)	$ (4,510,000)	$ (867,000)	(1,732,000)	(184,628,000)	$ 683,000	$ (443,000)	(470,000)	$ (8,572,000)	$ (184,858,000)	$ 92,000
Deferred tax assets:
Operating loss carryforwards												369,642,000	369,695,000
Tax credit carryforwards												64,760,000	51,030,000
Compensation related differences												48,349,000	33,378,000
Lease assets												31,938,000	30,782,000
Other temporary differences												6,136,000	7,049,000
Tax assets before valuation allowance												520,825,000	491,934,000
Less - Valuation allowance												(157,629,000)	(120,679,000)
Total deferred tax assets												363,196,000	371,255,000
Deferred tax liabilities
Convertible notes												(145,925,000)	(83,163,000)
Amortization												(197,847,000)	(270,421,000)
Property, plant and equipment												(4,580,000)	(5,913,000)
Lease liabilities												(30,312,000)	(29,586,000)
Other temporary differences												(4,078,000)	(2,607,000)
Total deferred tax liabilities												(382,742,000)	(391,690,000)
Net deferred tax liabilities												(19,546,000)	$ (20,435,000)
Differences between the effective income tax rate and the statutory tax rate
U.S. Federal statutory rate									21.00%	21.00%	21.00%
State taxes									1.90%	5.80%	3.40%
Federal and state tax rate changes									0.00%	(0.40%)	0.00%
Foreign tax rate differential									(1.00%)	0.60%	0.00%
Acquired IPR&D asset expense									(9.10%)	0.00%	0.00%
Research and development tax credits									1.60%	1.10%	1.90%
Stock-based compensation expense									1.10%	22.10%	9.10%
Non-deductible executive compensation									(0.80%)	(4.10%)	(4.90%)
Transaction costs									(0.10%)	(0.70%)	0.00%
Other adjustments									(1.00%)	(0.60%)	1.10%
Valuation allowance									(12.70%)	24.00%	(31.70%)
Effective tax rate									0.90%	68.80%	(0.10%)
Reconciliation of the amounts of unrecognized tax benefits
Beginning of the period				$ 10,276,000				$ 1,926,000	$ 10,276,000	$ 1,926,000	$ 0
Increase due to current year tax positions									3,600,000	2,142,000	392,000
Increase due to prior year tax positions									2,753,000	6,208,000	1,534,000
Decrease due to prior year tax positions									0	0	0
Settlements									0	0	0
Ending of the period	$ 16,629,000				$ 10,276,000				16,629,000	10,276,000	1,926,000
Genomic Health Inc
Operating Loss Carryforwards [Line Items]
Income tax benefit (expense)									8,600,000	(185,100,000)
Expense (benefit) for income taxes
Total income tax expense (benefit)									(8,600,000)	185,100,000
Federal
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards												1,550,000,000
Expense (benefit) for income taxes
Current expense (benefit):									(3,000)	0	0
Deferred tax expense (benefit):									(6,453,000)	(169,727,000)	0
Federal | Research
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards												54,300,000
State
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards												709,200,000
Expense (benefit) for income taxes
Current expense (benefit):									802,000	314,000	92,000
Deferred tax expense (benefit):									(3,971,000)	(15,397,000)	0
State | Research
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards												34,000,000
Foreign
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards												$ 4,300,000
Expense (benefit) for income taxes
Current expense (benefit):									933,000	(63,000)	0
Deferred tax expense (benefit):									$ 120,000	$ 15,000	$ 0

INCOME TAXES - Deferred Tax Ass

INCOME TAXES - Deferred Tax Asset, Valuation Allowance RollForward (Details) - Deferred tax asset - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning balance	$ (120,679)	$ (209,868)	$ (214,250)
Valuation allowances established	(108,944)	(132,522)	(52,855)
Changes to existing valuation allowances	1,662	1,620	(2,744)
Acquisition and purchase accounting	(5,558)	183,730	(1,739)
Additional paid-in-capital	75,890	36,361	61,720
Ending balance	$ (157,629)	$ (120,679)	$ (209,868)

SUBSEQUENT EVENTS (Details)

SUBSEQUENT EVENTS (Details) $ in Thousands, € in Millions	Feb. 12, 2021USD ($)shares	Feb. 12, 2021EUR (€)shares	Jan. 11, 2021USD ($)shares	Jan. 11, 2021EUR (€)shares	Jan. 05, 2021USD ($)	Jan. 05, 2021EUR (€)	Nov. 08, 2019USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Subsequent Event [Line Items]
Business combination, consideration transferred							$ 2,470,000
Contingent consideration, liability								$ 2,477	$ 2,879
Subsequent Event
Subsequent Event [Line Items]
Stock issued to acquire intangible assets, value			$ 27,300
Subsequent Event | Translational Genomics Research Institute | Licensing Agreements
Subsequent Event [Line Items]
Purchases of intangible assets			$ 25,000
Payment to acquire exclusive license (in shares) | shares			191,336	191,336
Subsequent Event | Ashion Analytics | Licensing Agreements
Subsequent Event [Line Items]
Net sales of a licensed product	$ 500,000
Cash investment	$ 72,000
Equity issued to acquire business (in shares) | shares	125,444	125,444
Subsequent Event | Sales Milestone Range One | Translational Genomics Research Institute | Licensing Agreements
Subsequent Event [Line Items]
Payment contingent upon achievement of milestone | €				€ 10
Net sales of a licensed product			$ 100,000
Subsequent Event | Sales Milestone Range One | Ashion Analytics | Licensing Agreements
Subsequent Event [Line Items]
Payment contingent upon achievement of milestone | €		€ 20
Subsequent Event | Sales Milestone Range Two | Translational Genomics Research Institute | Licensing Agreements
Subsequent Event [Line Items]
Payment contingent upon achievement of milestone | €				€ 35
Net sales of a licensed product			$ 250,000
Subsequent Event | Sales Milestone Range Two | Ashion Analytics | Licensing Agreements
Subsequent Event [Line Items]
Payment contingent upon achievement of milestone | €		€ 30
Thrive | Subsequent Event
Subsequent Event [Line Items]
Business combination, consideration transferred					$ 1,700,000
Business combination, percent of cash consideration transferred					35.00%
Business combination, percent of equity consideration transferred					65.00%
Contingent consideration, liability					$ 450,000
Thrive | Subsequent Event | Sales Milestone Range One | John Hopkins License Agreement | Licensing Agreements
Subsequent Event [Line Items]
Payment contingent upon achievement of milestone | €						€ 10
Net sales of a licensed product					500,000
Thrive | Subsequent Event | Sales Milestone Range Two | John Hopkins License Agreement | Licensing Agreements
Subsequent Event [Line Items]
Payment contingent upon achievement of milestone | €						15
Net sales of a licensed product					1,000,000
Thrive | Subsequent Event | Sales Milestone Range Three | John Hopkins License Agreement | Licensing Agreements
Subsequent Event [Line Items]
Payment contingent upon achievement of milestone | €						€ 20
Net sales of a licensed product					$ 1,500,000

QUARTERLY RESULTS OF OPERATIO_3

QUARTERLY RESULTS OF OPERATIONS (UNAUDITED) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 466,339	$ 408,363	$ 268,868	$ 347,821	$ 295,575	$ 218,805	$ 199,870	$ 162,043	$ 1,491,391	$ 876,293	$ 454,462
Cost of sales (exclusive of amortization of acquired intangible assets)	99,765	95,061	77,892	81,606	70,416	52,335	51,139	42,827	354,324	216,717	116,644
Amortization of acquired intangible assets	20,553	20,555	20,555	20,464	11,981	424	424	425
Gross profit	346,021	292,747	170,421	245,751	213,178	166,046	148,307	118,791
Operating expenses	761,323	496,082	237,430	328,124	309,258	201,772	182,209	186,865
Interest income and interest expense	(22,971)	(21,059)	(20,000)	(25,056)	(10,575)	(4,116)	(5,043)	(15,335)	(89,086)	(35,069)	(15,586)
Income tax benefit (expense)	1,463	4,510	867	1,732	184,628	(683)	443	470	8,572	184,858	(92)
Net loss	$ (436,810)	$ (219,884)	$ (86,142)	$ (105,697)	$ 77,973	$ (40,525)	$ (38,502)	$ (82,939)	$ (848,533)	$ (83,993)	$ (175,149)
Net income (loss) per share, basic (in dollars per share)	$ (2.79)	$ (1.46)	$ (0.58)	$ (0.71)	$ 0.56	$ (0.31)	$ (0.30)	$ (0.66)
Net income (loss) per share, diluted (in dollars per share)	$ (2.79)	$ (1.46)	$ (0.58)	$ (0.71)	$ 0.54	$ (0.31)	$ (0.30)	$ (0.66)
Weighted average number of shares outstanding, basic (in shares)	156,470	150,155	149,727	148,151	139,901	129,567	129,182	126,248
Weighted average number of shares outstanding, diluted (in shares)	156,470	150,155	149,727	148,151	143,200	129,567	129,182	126,248