BUSINESS COMBINATIONS - Genomic Health, Inc (Details) $ / shares in Units, $ in Thousands		1 Months Ended	3 Months Ended	12 Months Ended
	Nov. 08, 2019 USD ($) $ / shares	Nov. 30, 2019 USD ($)	Dec. 31, 2019 USD ($) country	Dec. 31, 2019 USD ($) country	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Acquisition
Number of countries in which entity operates | country			90	90
Total fair value consideration				$ 2,500,000	$ 24,500
Weighted average period for recognition of unrecognized compensation cost				2 years 5 months 4 days
Business Combination, Consideration Transferred for Genomic Health
Stock issued during period, value, acquisitions				$ 1,407,080	0	$ 0
Total purchase price				2,500,000	24,500
Underlying assets acquired and liabilities assumed based upon their estimated fair values at date of acquisition
Goodwill			$ 1,203,197	$ 1,203,197	17,279	$ 1,979
Trade name
Underlying assets acquired and liabilities assumed based upon their estimated fair values at date of acquisition
Estimated useful life				15 years 10 months 24 days
Acquired developed technology
Underlying assets acquired and liabilities assumed based upon their estimated fair values at date of acquisition
Estimated useful life				9 years 10 months 24 days
Genomic Health Inc
Acquisition
Acquisition related costs				$ 22,500
Total fair value consideration	$ 2,469,000	$ 2,500,000
Share conversion ratio	0.76534
Business Combination, Consideration Transferred for Genomic Health
Cash investment	$ 1,062,000
Stock issued during period, value, acquisitions	1,389,000	1,400,000
Aggregate purchase price	18,000
Total purchase price	2,469,000	$ 2,500,000
Disclosure Text Block Supplement [Abstract]
Severance benefits expense			32,100
Underlying assets acquired and liabilities assumed based upon their estimated fair values at date of acquisition
Cash and cash equivalents	87,627
Marketable securities	201,519
Accounts receivable	57,400
Inventory	3,535
Prepaid expenses and other current assets	8,360
Property, plant and equipment	69,905
Goodwill	1,185,918		$ 1,200,000	1,200,000
Operating lease right-of-use assets	80,790
Other long-term assets	14,972
Accounts payable, accrued liabilities and other current liabilities	(88,995)
Deferred tax liability	(205,536)
Operating lease liabilities, current portion	(3,258)
Operating lease liabilities, less current portion	(71,270)
Other long-term liabilities	(2,399)
Total fair value consideration	2,468,568
Pro Forma Information
Total revenues				66,174
Net loss before tax				(40,446)
Total revenues				1,266,591	848,573
Net loss before tax				$ (252,203)	$ (302,173)
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
Disclosure Text Block Supplement [Abstract]
Risk-free interest rates, minimum	0.88%
Risk-free interest rates, maximum	2.90%
Dividend yield	0.00%
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 | Minimum | Options
Disclosure Text Block Supplement [Abstract]
Expected term	3 years 3 months 10 days
Expected volatility	63.54%
Weighted average fair value per share of options assumed (in dollars per share) | $ / shares	$ 45.75
Genomic Health Inc | Maximum | Options
Disclosure Text Block Supplement [Abstract]
Expected term	6 years 8 months 23 days
Expected volatility	69.09%
Weighted average fair value per share of options assumed (in dollars per share) | $ / shares	$ 57.44
Genomic Health Inc | Trade name
Acquisition
Identifiable intangible assets	$ 100,000
Underlying assets acquired and liabilities assumed based upon their estimated fair values at date of acquisition
Identifiable intangible assets	$ 100,000
Estimated useful life	16 years			16 years
Genomic Health Inc | Supply Agreement
Acquisition
Identifiable intangible assets	$ 30,000
Underlying assets acquired and liabilities assumed based upon their estimated fair values at date of acquisition
Identifiable intangible assets	30,000
Genomic Health Inc | Acquired developed technology
Acquisition
Identifiable intangible assets	800,000
Underlying assets acquired and liabilities assumed based upon their estimated fair values at date of acquisition
Identifiable intangible assets	$ 800,000
Estimated useful life	10 years			10 years
Genomic Health Inc | In-process research and development
Acquisition
Identifiable intangible assets	$ 200,000
Underlying assets acquired and liabilities assumed based upon their estimated fair values at date of acquisition
Identifiable intangible assets	$ 200,000