Regeneron Pharmaceuticals (REGN) 10-Q 5 Aug 14 2014 Q2 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	6 Months Ended
	Jun. 30, 2014	Jul. 17, 2014	Jul. 17, 2014
		Common Stock	Class A Stock
Entity Information [Line Items]	'	'	'
Entity Registrant Name	'REGENERON PHARMACEUTICALS INC	'	'
Entity Central Index Key	'0000872589	'	'
Current Fiscal Year End Date	'--12-31	'	'
Entity Filer Category	'Large Accelerated Filer	'	'
Document Type	'10-Q	'	'
Document Period End Date	30-Jun-14	'	'
Document Fiscal Year Focus	'2014	'	'
Document Fiscal Period Focus	'Q2	'	'
Amendment Flag	'false	'	'
Entity Common Stock, Shares Outstanding	'	99,086,588	1,979,055

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	3 Months Ended	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2014	Dec. 31, 2013
Other Collaboration Revenue	$97,295	$222,607	'
Current assets:	'	'	'
Cash and cash equivalents	600,135	600,135	535,608
Marketable securities	216,774	216,774	158,376
Accounts receivable - trade, net	664,075	664,075	787,071
Accounts Receivable from Sanofi	116,865	116,865	104,707
Accounts receivable from Bayer HealthCare	112,984	112,984	63,189
Inventories	109,897	109,897	70,354
Deferred tax assets	37,291	37,291	44,677
Prepaid expenses and other current assets	60,674	60,674	32,952
Total current assets	1,918,695	1,918,695	1,796,934
Marketable securities	550,818	550,818	389,891
Property, plant, and equipment, at cost, net of accumulated depreciation and amortization	707,321	707,321	526,983
Deferred tax assets	270,367	270,367	231,878
Other assets	8,877	8,877	5,327
Total assets	3,456,078	3,456,078	2,951,013
Current liabilities:	'	'	'
Accounts payable and accrued expenses	283,385	283,385	250,896
Deferred revenue from Sanofi, current portion	12,979	12,979	12,815
Deferred revenue - other, current portion	54,154	54,154	34,185
Facility lease obligations, current portion	1,060	1,060	939
Total current liabilities	351,578	351,578	298,835
Deferred revenue from Sanofi	75,862	75,862	76,522
Deferred Revenue - other	128,042	128,042	107,677
Facility lease obligations	234,525	234,525	184,258
Convertible senior notes	282,261	282,261	320,315
Other long-term liabilities	14,968	14,968	11,330
Total liabilities	1,087,236	1,087,236	998,937
Stockholders' equity:	'	'	'
Preferred Stock	0	0	0
Additional paid-in capital	2,342,839	2,342,839	2,045,857
Retained earnings (accumulated deficit)	65,486	65,486	-92,692
Accumulated other comprehensive income (loss)	4,263	4,263	-1,188
Treasury stock	-43,848	-43,848	0
Total stockholders' equity	2,368,842	2,368,842	1,952,076
Total liabilities and stockholders' equity	3,456,078	3,456,078	2,951,013
Class A Stock	'	'	'
Stockholders' equity:	'	'	'
Common stock	2	2	2
Common Stock	'	'	'
Stockholders' equity:	'	'	'
Common stock	100	100	97
Treasury Stock	'	'	'
Stockholders' equity:	'	'	'
Total stockholders' equity	($43,848)	($43,848)	$0

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Jun. 30, 2014	Dec. 31, 2013
Stockholders' equity:	'	'
Preferred stock, par value (in dollars per share)	$0.01	$0.01
Preferred stock, shares authorized (in shares)	30,000,000	30,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Treasury Stock, shares outstanding (in shares)	521,876	0
Class A Stock	'	'
Stockholders' equity:	'	'
Common Stock, par value (in dollars per share)	$0.00	$0.00
Common Stock, shares authorized (in shares)	40,000,000	40,000,000
Common Stock, shares issued (in shares)	1,998,785	2,020,481
Common Stock, shares outstanding (in shares)	1,998,785	2,020,481
Common Stock	'	'
Stockholders' equity:	'	'
Common Stock, par value (in dollars per share)	$0.00	$0.00
Common Stock, shares authorized (in shares)	160,000,000	160,000,000
Common Stock, shares issued (in shares)	99,545,307	97,666,814
Common Stock, shares outstanding (in shares)	99,545,307	97,666,814

CONSOLIDATED_STATEMENTS_OF_OPE

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) (USD $)	3 Months Ended		6 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Revenues:	'	'	'	'
Net product sales	$418,022	$333,893	$780,400	$652,633
Sanofi collaboration revenue	142,595	85,529	273,103	184,802
Bayer HealthCare collaboration revenue	97,295	31,104	222,607	46,011
Technology licensing and other revenue	7,788	7,116	15,330	13,860
Total revenues	665,700	457,642	1,291,440	897,306
Expenses:	'	'	'	'
Research and development	294,501	187,463	581,880	367,762
Selling, general, and administrative	102,414	72,463	211,264	149,723
Cost of goods sold	29,945	27,283	57,418	55,304
Cost of collaboration manufacturing	16,434	12,330	32,533	13,364
Total expenses	443,294	299,539	883,095	586,153
Income from operations	222,406	158,103	408,345	311,153
Other income (expense):	'	'	'	'
Investment income	1,677	954	2,614	1,410
Interest expense	-10,177	-11,365	-21,790	-23,040
Loss on extinguishment of debt	-10,787	0	-10,787	0
Total other income (expense)	-19,287	-10,411	-29,963	-21,630
Income before income taxes	203,119	147,692	378,382	289,523
Income tax expense	-110,384	-60,316	-220,204	-103,273
Net income	92,735	87,376	158,178	186,250
Net income per share - basic	$0.92	$0.89	$1.58	$1.91
Net income per share - diluted	$0.82	$0.79	$1.40	$1.69
Weighted average shares outstanding - basic	100,391	97,700	100,085	97,289
Weighted average shares outstanding - diluted	113,032	111,060	113,121	110,305
Statements of Comprehensive Income	'	'	'	'
Net income	92,735	87,376	158,178	186,250
Other comprehensive income (loss):	'	'	'	'
Unrealized gain (loss) on marketable securities, net of tax	2,798	-1,785	5,451	-2,263
Comprehensive income	$95,533	$85,591	$163,629	$183,987

CONSOLIDATED_STATEMENTS_OF_STO

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $)	Total	Common Stock	Additional Paid-in Capital	Retained Earnings (Accumulated Deficit)	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Class A Stock
In Thousands, except Share data, unless otherwise specified							Common Stock
Balance at Dec. 31, 2012	$1,245,385	$95	$1,763,508	($517,054)	$0	($1,166)	$2
Balance (shares) at Dec. 31, 2012	'	95,223,000	'	'	0	'	2,069,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'
Issuance of Common Stock in connection with exercise of stock options	30,498	2	30,496	'	'	'	'
Issuance of Common Stock in connection with exercise of stock options (shares)	'	1,661,000	'	'	'	'	'
Common Stock tendered upon exercise of stock options in connection with employee tax obligations	-73,137	0	-73,137	'	'	'	'
Common Stock tendered upon exercise of stock options in connection with employee tax obligations (in shares)	'	-290,000	'	'	'	'	'
Issuance of Common Stock in connection with Company 401(k) Savings Plan contribution	0	0	'	'	'	'	'
Issuance of Common Stock in connection with Company 401(k) Savings Plan contribution (in shares)	'	38,000	'	'	'	'	'
Conversion of Class A Stock to Common Stock (in shares)	'	30,000	'	'	'	'	-30,000
Stock-based compensation charges	98,728	'	98,728	'	'	'	'
Excess tax benefit from stock-based compensation	7,876	'	7,876	'	'	'	'
Net income	186,250	'	'	186,250	'	'	'
Other comprehensive income, net of tax	-2,263	'	'	'	'	-2,263	'
Balance at Jun. 30, 2013	1,493,337	97	1,827,471	-330,804	0	-3,429	2
Balance (shares) at Jun. 30, 2013	'	96,662,000	'	'	0	'	2,039,000
Balance at Dec. 31, 2013	1,952,076	97	2,045,857	-92,692	0	-1,188	2
Balance (shares) at Dec. 31, 2013	'	97,667,000	'	'	0	'	2,020,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'
Issuance of Common Stock in connection with exercise of stock options	62,117	2	62,115	'	'	'	'
Issuance of Common Stock in connection with exercise of stock options (shares)	'	1,514,000	'	'	'	'	'
Common Stock tendered upon exercise of stock options in connection with employee tax obligations	-64,990	0	-64,990	'	'	'	'
Common Stock tendered upon exercise of stock options in connection with employee tax obligations (in shares)	'	-205,000	'	'	'	'	'
Issuance of Common Stock in connection with conversion of convertible senior notes	156,368	1	156,367	'	'	'	'
Issuance of Common Stock in connection with conversion of convertible senior notes (in shares)	521,876	522,000	'	'	'	'	'
Issuance of Common Stock in connection with Company 401(k) Savings Plan contribution	0	0	'	'	'	'	'
Issuance of Common Stock in connection with Company 401(k) Savings Plan contribution (in shares)	'	21,000	'	'	'	'	'
Issuance of restricted Common Stock under Long-Term Incentive Plan	0	0	'	'	'	'	'
Issuance of restricted Common Stock under Long-Term Incentive Plan (in shares)	'	5,000	'	'	'	'	'
Conversion of Class A Stock to Common Stock (in shares)	'	21,000	'	'	'	'	-21,000
Stock-based compensation charges	155,137	'	155,137	'	'	'	'
Excess tax benefit from stock-based compensation	244,197	'	244,197	'	'	'	'
Acquisition of Common Stock in connection with exercise of convertible note hedges	0	'	43,848	'	-43,848	'	'
Acquisition of Common Stock in connection with exercise of convertible note hedges (in shares)	-521,876	'	'	'	-522,000	'	'
Reduction of warrants in connection with conversion of senior notes	-143,041	'	-143,041	'	'	'	'
Reduction of equity component of convertible senior notes	-156,651	'	-156,651	'	'	'	'
Net income	158,178	'	'	158,178	'	'	'
Other comprehensive income, net of tax	5,451	'	'	'	'	5,451	'
Balance at Jun. 30, 2014	$2,368,842	$100	$2,342,839	$65,486	($43,848)	$4,263	$2
Balance (shares) at Jun. 30, 2014	'	99,545,000	'	'	-522,000	'	1,999,000

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Cash flows from operating activities:	'	'
Net income	$158,178	$186,250
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Depreciation and amortization	24,546	19,109
Non-cash compensation expense	151,920	97,473
Non-cash interest expense	10,871	11,315
Losses on Extinguishment of Debt	10,787	0
Other non-cash charges and expenses, net	6,598	18,323
Deferred taxes	-32,543	92,522
Changes in assets and liabilites	'	'
Decrease (increase) in Sanofi, Bayer HealthCare, and trade accounts receivable	61,043	-206,149
Increase in Inventories	-37,295	-31,144
(Increase) decrease in prepaid expenses and other assets	-29,446	2,700
Increase (decrease) in deferred revenue	39,838	-11,579
Increase in accounts payable, accrued expenses and other liabilities	16,820	35,592
Total adjustments	223,139	28,162
Net cash provided by operating activities	381,317	214,412
Cash flows from investing activities:	'	'
Purchases of marketable securities	-374,509	-282,643
Sales or maturities of marketable securities	155,850	307,244
Capital expenditures	-135,695	-55,656
Net cash used in investing activities	-354,354	-31,055
Cash flows from financing activities:	'	'
Payments in connection with facility and capital lease obligations	-534	-997
Repayments of convertible senior notes	-61,125	0
Payments in connection with deduction of outstanding warrants	-143,041	0
Proceeds from issuance of Common Stock	63,057	34,300
Payments in connection with Common Stock tendered for employee tax obligations	-64,990	-73,137
Excess tax benefit from stock-based compensation	244,197	7,876
Net cash provided by (used in) financing activities	37,564	-31,958
Net increase in cash and cash equivalents	64,527	151,399
Cash and cash equivalents at beginning of period	535,608	230,276
Cash and cash equivalents at end of period	$600,135	$381,675

Interim_Financial_Statements_N

Interim Financial Statements (Notes)	6 Months Ended
	Jun. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Interim Financial Statements	'
	Interim Financial Statements
	The interim Condensed Consolidated Financial Statements of Regeneron Pharmaceuticals, Inc. ("Regeneron" or the "Company") have been prepared in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all information and disclosures necessary for a presentation of the Company’s financial position, results of operations, and cash flows in conformity with accounting principles generally accepted in the United States of America. In the opinion of management, these financial statements reflect all normal recurring adjustments and accruals necessary for a fair statement of the Company’s financial position, results of operations, and cash flows for such periods. The results of operations for any interim periods are not necessarily indicative of the results for the full year. The December 31, 2013 Condensed Consolidated Balance Sheet data were derived from audited financial statements, but do not include all disclosures required by accounting principles generally accepted in the United States of America. These financial statements should be read in conjunction with the financial statements and notes thereto contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013.
	Certain reclassifications have been made to prior period amounts to conform with the current period’s presentation.

Net_Product_Sales_Notes

Net Product Sales (Notes)	6 Months Ended
	Jun. 30, 2014
Revenues [Abstract]	'
Net Product Sales	'
	Net Product Sales
	EYLEA® net product sales in the United States totaled $414.8 million and $329.8 million for the three months ended June 30, 2014 and 2013, respectively, and $773.8 million and $643.7 million for the six months ended June 30, 2014 and 2013, respectively. In addition, ARCALYST® net product sales totaled $3.2 million and $4.1 million for the three months ended June 30, 2014 and 2013, respectively, and $6.6 million and $8.9 million for the six months ended June 30, 2014 and 2013, respectively.
	The Company recorded 73% and 76% for the three months ended June 30, 2014 and 2013, respectively, and 76% and 77% for the six months ended June 30, 2014 and 2013, respectively, of its total gross product revenue from sales to Besse Medical, a subsidiary of AmerisourceBergen Corporation.
	Revenue from product sales is recorded net of applicable provisions for rebates and chargebacks under governmental programs (including Medicaid), distribution-related fees, prompt pay discounts, and other sales-related deductions. The following table summarizes the provisions, and credits/payments, for these sales-related deductions during the six months ended June 30, 2014.
		Rebates &			Distribution-			Other Sales-			Total
		Chargebacks			Related			Related
					Fees			Deductions
	Balance as of December 31, 2013	$	4,400		$	19,663		$	538		$	24,601
	Provision related to current period sales	14,817			36,206			818			51,841
	Credits/payments	(15,077		)	(35,449		)	(834		)	(51,360		)
	Balance as of June 30, 2014	$	4,140		$	20,420		$	522		$	25,082

Collaboration_Agreements_Notes

Collaboration Agreements (Notes)	6 Months Ended
	Jun. 30, 2014
Collaboration Agreement [Abstract]	'
Collaboration Agreements	'
	Collaboration Agreements
	Sanofi
	The collaboration revenue the Company earned from Sanofi, as detailed below, consisted primarily of reimbursement for research and development expenses that the Company incurred in connection with the companies' antibody collaboration. In addition, Sanofi collaboration revenue for the three months and six months ended June 30, 2013 was reduced by two $10.0 million up-front payments to Sanofi in connection with the Company's acquisition from Sanofi of full exclusive rights to two families of novel antibodies, as described below.
		Three months ended
		June 30,
	Sanofi Collaboration Revenue	2014			2013
	ZALTRAP:
	Regeneron's share of losses in connection with commercialization of ZALTRAP	$	(692	)	$	(8,216	)
	Reimbursement of Regeneron research and development expenses	1,338			1,992
	Other	1,484			2,227
	Total ZALTRAP	2,130			(3,997		)
	Antibody:
	Reimbursement of Regeneron research and development expenses	137,893			105,274
	Regeneron's share of commercialization expenses	(4,295		)	—
	Up-front payments to Sanofi for acquisition of rights related to two antibodies	—			(20,000		)
	Other	6,867			4,252
	Total Antibody	140,465			89,526
	Total Sanofi collaboration revenue	$	142,595		$	85,529
		Six months ended
		June 30,
	Sanofi Collaboration Revenue	2014			2013
	ZALTRAP:
	Regeneron's share of losses in connection with commercialization of ZALTRAP	$	(3,904	)	$	(16,005	)
	Reimbursement of Regeneron research and development expenses	2,430			4,081
	Other	3,661			4,084
	Total ZALTRAP	2,187			(7,840		)
	Antibody:
	Reimbursement of Regeneron research and development expenses	264,715			204,898
	Regeneron's share of commercialization expenses	(4,295		)	—
	Up-front payments to Sanofi for acquisition of rights related to two antibodies	—			(20,000		)
	Other	10,496			7,744
	Total Antibody	270,916			192,642
	Total Sanofi collaboration revenue	$	273,103		$	184,802
	Sanofi commenced sales of ZALTRAP (ziv-aflibercept) Injection for Intravenous Infusion, in combination with 5-fluorouracil, leucovorin, irinotecan ("FOLFIRI"), for patients with metastatic colorectal cancer that is resistant to or has progressed following an oxaliplatin-containing regimen, in the United States in the third quarter of 2012 and in certain European and other countries in the first quarter of 2013. The Company and Sanofi globally collaborate on the development and commercialization of ZALTRAP. Under the terms of the companies' September 2003 collaboration agreement, as amended, Regeneron and Sanofi share co-promotion rights and profits and losses on sales of ZALTRAP outside of Japan. The Company is entitled to a receive a percentage of sales of ZALTRAP in Japan.
	Under the Company's antibody collaboration agreement with Sanofi, agreed upon worldwide development expenses incurred by both companies during the term of the agreement are funded by Sanofi, except that following receipt of the first positive Phase 3 trial results for a co-developed drug candidate, which first occurred in the fourth quarter of 2013, subsequent Phase 3 trial-related costs for that drug candidate ("Shared Phase 3 Trial Costs") are shared 80% by Sanofi and 20% by Regeneron. Consequently, during the three and six months ended June 30, 2014, the Company recognized as additional research and development expense $29.1 million and $52.9 million, respectively, of antibody development expenses that the Company was obligated to reimburse to Sanofi related to alirocumab and sarilumab.
	Effective in the second quarter of 2014, the Company and Sanofi began sharing pre-launch commercialization expenses related to alirocumab in accordance with the companies’ antibody collaboration agreement.
	In May 2013, the Company acquired from Sanofi full exclusive rights to two families of novel antibodies invented at Regeneron and previously included in the Company's antibody collaboration with Sanofi. The Company acquired full rights to antibodies targeting the platelet derived growth factor (PDGF) family of receptors and ligands in ophthalmology and all other indications and to antibodies targeting the angiopoietin-2 (Ang2) receptor and ligand in ophthalmology. With respect to PDGF antibodies, the Company made a $10.0 million up-front payment to Sanofi in the second quarter of 2013. In addition, with respect to Ang2 antibodies in ophthalmology, the Company made a $10.0 million up-front payment to Sanofi in the second quarter of 2013.
	With respect to PDGF antibodies, the Company made two $5.0 million development milestone payments to Sanofi in the first quarter of 2014, which were recorded in the Company's Statements of Operations as research and development expense. The Company is also obligated to pay up to $30.0 million in additional potential development milestones as well as royalties on any future sales of PDGF antibodies.
	Bayer HealthCare LLC
	The Company and Bayer HealthCare globally collaborate on the development and commercialization of EYLEA outside of the United States. Bayer HealthCare commenced sales of EYLEA outside the United States for the treatment of wet AMD in the fourth quarter of 2012 and for the treatment of macular edema secondary to CRVO in the fourth quarter of 2013. In addition, in January 2014, the Company entered into a license and collaboration agreement with Bayer HealthCare governing the joint development and commercialization outside the United States of an antibody product candidate to Platelet Derived Growth Factor Receptor Beta (PDGFR-beta).
	The collaboration revenue the Company earned from Bayer HealthCare is detailed below:
		Three months ended
		June 30,
	Bayer HealthCare Collaboration Revenue	2014			2013
	EYLEA:
	Regeneron's net profit in connection with commercialization of EYLEA outside the United States	$	66,781		$	19,055
	Sales milestones	15,000			—
	Cost-sharing of Regeneron EYLEA development expenses	1,494			3,629
	Other	10,813			8,420
	Total EYLEA	94,088			31,104
	PDGFR-beta antibody:
	Cost-sharing of REGN2176-3 development expenses	626			—
	Other	2,581			—
	Total PDGFR-beta	3,207			—
	Total Bayer HealthCare collaboration revenue	$	97,295		$	31,104
		Six months ended
		June 30,
	Bayer HealthCare Collaboration Revenue	2014			2013
	EYLEA:
	Regeneron's net profit in connection with commercialization of EYLEA outside the United States	$	127,940		$	25,417
	Sales milestones	45,000			—
	Cost-sharing of Regeneron EYLEA development expenses	21,841			9,466
	Other	21,745			11,128
Total EYLEA	216,526			46,011
PDGFR-beta antibody:
Cost-sharing of REGN2176-3 development expenses	1,139			—
Other	4,942			—
Total PDGFR-beta	6,081			—
Total Bayer HealthCare collaboration revenue	$	222,607		$	46,011
EYLEA
In the first and second quarters of 2014, the Company earned, and recorded as revenue, two $15.0 million sales milestones and one $15.0 million sales milestone, respectively, from Bayer HealthCare upon total aggregate net sales of EYLEA outside the United States exceeding $500 million, $600 million, and $700 million, respectively, over a twelve-month period. The Company is eligible to receive up to $45.0 million in additional sales milestone payments if twelve-month sales of EYLEA outside the United States achieve certain specified levels up to $1 billion. In addition, in connection with a November 2013 agreement under which Bayer HealthCare obtained rights to use certain of the Company’s EYLEA clinical data for a regulatory filing, the Company became eligible to receive up to $30.0 million in additional sales milestone payments if twelve-month sales of specific commercial supplies of EYLEA outside the United States achieve certain specified levels up to $200 million.
In January 2014, Bayer HealthCare decided to participate in the global development and commercialization of EYLEA outside the United States for the treatment of macular edema following branch retinal vein occlusion ("BRVO"). In connection with this decision, Bayer HealthCare reimbursed Regeneron $15.7 million for a defined share of the EYLEA global development costs that the Company had incurred prior to February 2014 for the BRVO indication, which was recognized as Bayer HealthCare collaboration revenue in the first quarter of 2014 and is included with "Cost-sharing of Regeneron EYLEA development expenses" for the six months ended June 30, 2014 in the table above. In addition, all future agreed upon global EYLEA development expenses incurred in connection with BRVO are being shared equally, and any future profits or losses on sales of EYLEA outside of the United States for the treatment of macular edema following BRVO will also be shared (for countries other than Japan). The Company is entitled to receive a tiered percentage of EYLEA net sales in Japan.
PDGFR-beta Antibody
In January 2014, the Company also entered into an agreement with Bayer HealthCare governing the joint development and commercialization outside the United States of an antibody product candidate to PDGFR-beta, including in combination with EYLEA, for the treatment of ocular diseases or disorders. REGN2176-3, a combination product candidate comprised of an antibody to PDGFR-beta co-formulated with EYLEA, is being developed under the agreement. Under the agreement, the Company will conduct the initial development of the PDGFR-beta antibody through completion of the first proof-of-concept study, upon which Bayer HealthCare will have a right to opt-in to license and collaborate on further development and commercialization outside the United States.
In connection with the agreement, Bayer HealthCare made a $25.5 million non-refundable upfront payment to the Company in January 2014, and is obligated to pay 25% of global development costs and 50% of development costs exclusively for the territory outside the United States under the initial development plan. In addition, Bayer HealthCare is obligated to reimburse the Company for 50% of development milestone payments to Sanofi related to the Company's acquisition of rights to antibodies targeting the PDGF family of receptors in May 2013, as described above. In that regard, Bayer HealthCare made two $2.5 million development milestone payments to the Company in the first quarter of 2014 (both of which, for the purpose of revenue recognition, were not considered substantive). Further, in connection with the Company’s initial development of the PDGFR-beta antibody through completion of the first proof-of-concept study, the Company is eligible to receive up to $15.0 million in future development milestone payments from Bayer HealthCare, although certain of these development milestone payments could be reduced by half if Bayer HealthCare does not opt-in to the collaboration.
From inception of the agreement until Bayer HealthCare has the right to opt-in to the collaboration, the Company's sole significant deliverable is research and development services provided in accordance with the agreement. Therefore, the $25.5 million upfront payment was allocated to this deliverable, initially recorded as deferred revenue, and will be recognized as revenue over the related performance period. In addition, the two $2.5 million non-substantive development milestone payments from Bayer HealthCare were also initially recorded as deferred revenue and will be recognized over the same performance period as the upfront payment.
If Bayer HealthCare exercises its right to opt-in to the collaboration, it will obtain exclusive commercialization rights to the product outside the United States, continue to pay for 25% of global development costs and 50% of development costs exclusively for the territory outside the United States, pay a $20.0 million opt-in payment to the Company, pay a $20.0 million development milestone to the Company upon receipt of the first marketing approval in the European Union or Japan, share profits and losses from sales outside the United States equally with the Company, and be responsible for the payment of royalties on sales outside the United States to Sanofi.
Within the United States, the Company has exclusive commercialization rights and will retain all of the profits from sales. If Bayer HealthCare does not opt-in to the collaboration, the Company will have exclusive rights to develop and commercialize PDGFR-beta antibodies (except as a combination product with EYLEA) for use outside the United States.
The Company also has the right to opt-out of the collaboration upon completion of the first proof-of-concept study for the PDGFR-beta antibody. If the Company opts-out of the collaboration and Bayer HealthCare exercises its right to opt-in to the collaboration, Bayer HealthCare will obtain exclusive rights to the PDGFR-beta antibody (except as a combination product with EYLEA) outside of the United States, be responsible for all development costs outside of the United States, be responsible for all royalty and milestone payments to a third party, and will retain all of the profits from sales of the PDGFR-beta antibody outside of the United States.
Unless terminated earlier in accordance with its provisions, the agreement will continue to be in effect until such time as neither party or its respective affiliates or sublicensees is developing or commercializing a PDGFR-beta antibody in the specified field outside of the United States and such discontinuation is acknowledged as permanent by both the Company and Bayer HealthCare in writing.
Avalanche Biotechnologies, Inc.
In May 2014, the Company entered into a research collaboration and license agreement with Avalanche Biotechnologies, Inc. to discover, develop, and commercialize novel gene therapy products for the treatment of ophthalmologic diseases. In connection with the agreement, the Company made a $2.0 million upfront payment and a $6.0 million pre-payment of collaboration research costs, and is obligated to pay potential additional research costs, an aggregate amount of up to $80.0 million per product upon meeting certain potential development and regulatory milestones (for products directed to as many as eight therapeutic targets, or up to an aggregate of $640.0 million), and royalties on any future sales of such products. The Company also purchased an aggregate of $5.0 million of Avalanche preferred stock. Under the agreement, the Company will collaborate with Avalanche to conduct research for the discovery of novel gene therapy vectors. Subsequent to the filing of an Investigational New Drug application ("IND") with the U.S. Food and Drug Administration ("FDA") for a product candidate developed under the agreement, Regeneron may exercise its right to obtain exclusive worldwide rights to further research, develop, and commercialize such product candidates directed to the applicable therapeutic target. In addition, Avalanche has the option to share in development costs and profits for products directed toward up to two therapeutic targets of its choice.
In July 2014, Avalanche commenced an initial public offering ("IPO") of its common stock and thereby triggered the Company's obligation under the research collaboration and license agreement to purchase up to $10.0 million of Avalanche common stock in a concurrent private placement. As part of the concurrent private placement, the Company has agreed, subject to customary closing conditions, to purchase from Avalanche at the closing of the IPO 588,235 shares of Avalanche common stock for an aggregate purchase price of $10.0 million. In addition, at the closing of the IPO, Avalanche preferred stock, including the Avalanche preferred stock held by the Company, will automatically convert on a one-for-one basis into Avalanche common stock.

Net_Income_Per_Share_Notes

Net Income Per Share (Notes)	6 Months Ended
	Jun. 30, 2014
Earnings Per Share [Abstract]	'
Net Income Per Share	'
	Net Income Per Share
	The Company’s basic net income per share amounts have been computed by dividing net income by the weighted average number of shares of Common Stock and Class A Stock outstanding. Net income per share is presented on a combined basis, inclusive of Common Stock and Class A Stock outstanding, as each class of stock has equivalent economic rights. Diluted net income per share includes the potential dilutive effect of other securities as if such securities were converted or exercised during the period, when the effect is dilutive. The calculations of basic and diluted net income per share are as follows:
		Three months ended June 30,
		2014			2013
	Net income - basic and diluted	$	92,735		$	87,376
	(Shares in thousands)
	Weighted average shares - basic	100,391			97,700
	Effect of dilutive securities:
	Stock options	9,359			10,291
	Restricted stock	405			424
	Warrants	2,877			2,645
	Dilutive potential shares	12,641			13,360
	Weighted average shares - diluted	113,032			111,060
	Net income per share - basic	$	0.92		$	0.89
	Net income per share - diluted	$	0.82		$	0.79
		Six months ended June 30,
		2014			2013
	Net income - basic and diluted	$	158,178		$	186,250
	(Shares in thousands)
	Weighted average shares - basic	100,085			97,289
	Effect of dilutive securities:
	Stock options	9,615			10,296
	Restricted stock	403			383
	Warrants	3,018			2,337
	Dilutive potential shares	13,036			13,016
	Weighted average shares - diluted	113,121			110,305
	Net income per share - basic	$	1.58		$	1.91
	Net income per share - diluted	$	1.4		$	1.69
	Shares which have been excluded from the June 30, 2014 and 2013 diluted per share amounts because their effect would have been antidilutive include the following:
		Three months ended June 30,
	(Shares in thousands)	2014		2013
	Stock options	3,765		1,247
	Convertible senior notes	4,662		4,761
		Six months ended June 30,
	(Shares in thousands)	2014		2013
	Stock options	3,714		3,599
	Convertible senior notes	4,711		4,761

Marketable_Securities_Notes

Marketable Securities (Notes)	6 Months Ended
	Jun. 30, 2014
Investments, Debt and Equity Securities [Abstract]	'
Marketable Securities	'
	Marketable Securities
	Marketable securities at June 30, 2014 and December 31, 2013 consist of both debt securities issued by investment grade institutions as well as equity securities. The following tables summarize the Company's investments in marketable securities at June 30, 2014 and December 31, 2013.
			Amortized			Unrealized						Fair
	At June 30, 2014		Cost Basis			Gains			Losses			Value
	U.S. government and government agency obligations		$	52,071		$	97		—			$	52,168
	Corporate bonds		647,052			1,108			$	(368	)	647,792
	Municipal bonds		46,336			190			—			46,526
	International government agency obligations		6,211			—			(1		)	6,210
	Certificates of deposit		7,920			2			—			7,922
	Equity securities		1,166			5,808			—			6,974
	Total marketable securities		$	760,756		$	7,205		$	(369	)	$	767,592
	At December 31, 2013
	U.S. government and government agency obligations		$	107,493		$	55		$	(27	)	$	107,521
	Corporate bonds		369,321			233			(361		)	369,193
	Commercial paper		23,891			53			—			23,944
	Municipal bonds		36,935			45			(59		)	36,921
	International government agency obligations		2,007			1			—			2,008
	Certificates of deposit		7,509			5			—			7,514
	Equity securities		1,166			—			—			1,166
	Total marketable securities		$	548,322		$	392		$	(447	)	$	548,267
	The Company classifies its debt securities based on their contractual maturity dates. The debt securities listed at June 30, 2014 mature at various dates through August 2024. The fair values of debt security investments by contractual maturity as of June 30, 2014 and December 31, 2013 consist of the following:
			June 30,			31-Dec-13
			2014
	Maturities within one year		$	216,774		$	158,376
	Maturities after one year through five years		538,647			383,410
	Maturities after five years through ten years		4,043			4,138
	Maturities after ten years		1,154			1,177
			$	760,618		$	547,101
	The following table shows the fair value of the Company’s marketable securities that have unrealized losses and that are deemed to be only temporarily impaired, aggregated by investment category and length of time that the individual securities have been in a continuous unrealized loss position, at June 30, 2014 and December 31, 2013.
		Less than 12 Months						12 Months or Greater					Total
	At June 30, 2014	Fair Value			Unrealized Loss			Fair Value			Unrealized Loss		Fair Value		Unrealized Loss
	Corporate bonds	$	157,970		$	(368	)	—			—		$	157,970	$	(368	)
	International government agency obligations	6,210			(1		)						6,210		(1		)
		$	164,180		$	(369	)	—			—		$	164,180	$	(369	)
	At December 31, 2013
	U.S. government and government agency obligations	$	49,241		$	(27	)	—			—		$	49,241	$	(27	)
	Corporate bonds	176,140			(361		)	—			—		176,140		(361		)
	Municipal bonds	14,431			(59		)	—			—		14,431		(59		)
		$	239,812		$	(447	)	—			—		$	239,812	$	(447	)
	Realized gains and losses are included as a component of investment income. For both the three and six months ended June 30, 2014, total realized gains and losses on sales of marketable securities were not material. For both the three and six months ended June 30, 2013, total realized gains on sales of marketable securities were $0.5 million and there were no realized losses. Changes in the Company's accumulated other comprehensive income (loss) for the three and six months ended June 30, 2014 and 2013 related to unrealized gains and losses on available-for-sale marketable securities. For the three and six months ended June 30, 2014 and 2013, amounts reclassified from accumulated other comprehensive income (loss) into investment income in the Company's Statements of Operations were related to realized gains and losses on sales of marketable securities.

Fair_Value_Measurements_Notes

Fair Value Measurements (Notes)	6 Months Ended
	Jun. 30, 2014
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	Fair Value Measurements
	The Company’s assets that are measured at fair value on a recurring basis, at June 30, 2014 and December 31, 2013, consist of the following:
				Fair Value Measurements at Reporting Date Using
	At June 30, 2014	Fair Value		Quoted Prices in		Significant Other
				Active Markets		Observable Inputs
				for Identical		(Level 2)
				Assets
				(Level 1)
	Available-for-sale marketable securities:
	U.S. government and government agency obligations	$	52,168	—		$	52,168
	Corporate bonds	647,792		—		647,792
	Municipal bonds	46,526		—		46,526
	International government agency obligations	6,210		—		6,210
	Certificates of deposit	7,922		—		7,922
	Equity securities	6,974		$	6,974	—
		$	767,592	$	6,974	$	760,618
	At December 31, 2013
	Available-for-sale marketable securities:
	U.S. government and government agency obligations	$	107,521	—		$	107,521
	Corporate bonds	369,193		—		369,193
	Commercial paper	23,944		—		23,944
	Municipal bonds	36,921		—		36,921
	International government agency obligations	2,008		—		2,008
	Certificates of deposit	7,514		—		7,514
	Equity securities	1,166		$	1,166	—
		$	548,267	$	1,166	$	547,101
	Marketable securities included in Level 2 were valued using a market approach utilizing prices and other relevant information, such as interest rates, yield curves, prepayment speeds, loss severities, credit risks, and default rates, generated by market transactions involving identical or comparable assets. The Company considers market liquidity in determining the fair value for these securities. The Company did not record any charges for other-than-temporary impairment of its Level 2 marketable securities during the three and six months ended June 30, 2014 and 2013.
	There were no purchases, sales, or maturities of Level 3 marketable securities and no unrealized gains or losses related to Level 3 marketable securities for the three and six months ended June 30, 2014 and 2013. There were no transfers of marketable securities between Levels 1, 2, or 3 classifications during the three and six months ended June 30, 2014 and 2013.
	As of June 30, 2014 and December 31, 2013, the Company had $338.9 million and $400.0 million, respectively, in aggregate principal amount of 1.875% convertible senior notes (the "Notes") that will mature on October 1, 2016 unless earlier converted or repurchased. As described in Note 9, a portion of the Notes was surrendered for conversion during the second quarter of 2014. The fair value of the outstanding Notes was estimated to be $1,090.8 million and $1,327.2 million as of June 30, 2014 and December 31, 2013, respectively, and was determined based on Level 2 inputs, such as market and observable sources.

Inventory_Notes

Inventory (Notes)	6 Months Ended
	Jun. 30, 2014
Inventory Disclosure [Abstract]	'
Inventory	'
	Inventories
	Inventories consist of the following:
		June 30,		December 31,
		2014		2013
	Raw materials	$	10,220	$	9,120
	Work-in-process	60,110		35,868
	Finished goods	12,215		14,352
	Deferred costs	27,352		11,014
		$	109,897	$	70,354
	Deferred costs represent the costs of product manufactured and shipped to the Company's collaborators for which recognition of revenue has been deferred. For the three months ended June 30, 2014 and 2013, cost of goods sold included inventory write-downs and reserves totaling $0.8 million and $1.7 million, respectively. For the six months ended June 30, 2014 and 2013, cost of goods sold included inventory write-downs and reserves totaling $1.9 million and $4.9 million, respectively.

Accounts_Payable_and_Accrued_E

Accounts Payable and Accrued Expenses (Notes)	6 Months Ended
	Jun. 30, 2014
Payables and Accruals [Abstract]	'
Accounts Payable and Accrued Expenses	'
	Accounts Payable and Accrued Expenses
	Accounts payable and accrued expenses consist of the following:
		June 30,		December 31,
		2014		2013
	Accounts payable	$	47,231	$	61,936
	Accrued payroll and related costs	51,786		69,429
	Accrued clinical trial expense	35,498		23,654
	Accrued sales-related charges, deductions, and royalties	100,333		66,855
	Other accrued expenses and liabilities	48,537		29,022
		$	283,385	$	250,896

Convertible_Debt_Notes

Convertible Debt (Notes)	6 Months Ended
	Jun. 30, 2014
Debt Disclosure [Abstract]	'
Debt Disclosure [Text Block]	'
	Convertible Debt
	In the second quarter of 2014, $61.1 million principal amount of the Company's $400.0 million aggregate principal amount of Notes were surrendered for conversion. In accordance with the terms of the Notes, the Company elected to settle these conversion obligations through a combination of cash, in an amount equal to the principal amount of the converted Notes, and shares of the Company's Common Stock in respect of any amounts due in excess thereof. Consequently, upon settlement of the Notes during the second quarter of 2014, the Company (i) paid $61.1 million in cash, (ii) issued 521,876 shares of Common Stock, (iii) recognized a $10.8 million loss on the debt extinguishment, and (iv) allocated $156.7 million of the settlement consideration provided to the Note holders to the reacquisition of the equity component of the Notes, and recognized such amount as a reduction of stockholder's equity.
	In connection with the initial offering of the Notes in October 2011, the Company entered into convertible note hedge and warrant transactions with multiple counterparties, which were recorded to additional paid-in capital. As a result of the Note conversions in the second quarter of 2014, the Company exercised a proportionate amount of its convertible note hedges, for which the Company received 521,876 shares of Common Stock, which was equivalent to the number of shares the Company was required to issue to settle the non-cash portion of the related Note conversions. The shares received were recorded as Treasury Stock, at cost, in the Company's Balance Sheet and Statement of Stockholders' Equity.
	Also during the second quarter of 2014, the Company entered into agreements to reduce the number of warrants held by each of the warrant holders in proportion to the amount of Notes converted. Pursuant to the agreements, the Company paid an aggregate amount of $143.0 million to the warrant holders to reduce the maximum number of shares of Common Stock issuable upon exercise of the warrants from 4,760,840 to 4,033,324 (subject to adjustment from time to time as provided in the applicable warrant agreements). The remaining warrants expire, and will be exercisable, at various dates during 2017.

Income_Taxes_Notes

Income Taxes (Notes)	6 Months Ended
	Jun. 30, 2014
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	Income Taxes
	The Company is subject to U.S. federal, state, and foreign income taxes. The Company recorded an income tax provision in its Statement of Operations of $110.4 million and $60.3 million for the three months ended June 30, 2014 and 2013, respectively, and $220.2 million and $103.3 million for the six months ended June 30, 2014 and 2013, respectively. The Company's effective tax rate was 54.3% and 40.8% for the three months ended June 30, 2014 and 2013, respectively, and 58.2% and 35.7% for the six months ended June 30, 2014 and 2013, respectively. The Company's effective tax rate for the three and six months ended June 30, 2014 was negatively impacted by losses incurred in foreign jurisdictions with rates lower than the federal statutory rate and expiration at the end of 2013 of the federal tax credit for increased research activities. In addition, the Company's effective tax rate for the six months ended June 30, 2014 was negatively impacted by New York State tax legislation enacted in the first quarter of 2014. This tax legislation reduced the New York State income tax rate to zero percent for "qualified manufacturers", including Regeneron, effective in 2014; however, it also resulted in the Company reducing its related deferred tax assets as a discrete item in the first quarter of 2014. As a result, this tax legislation caused a net increase in the Company's effective tax rate by 3.9% for the six months ended June 30, 2014.
	The Company's effective tax rate for the six months ended June 30, 2013 included, as a discrete item in the first quarter of 2013, the favorable impact of the enactment of The American Taxpayer Relief Act in January 2013. The American Taxpayer Relief Act included a provision to extend the income tax credit for increased research activities retroactively to the tax year ended December 31, 2012, as well as for 2013. As a result, the Company's 2012 research tax credit reduced its effective tax rate for the six months ended June 30, 2013 by 6.0%.
	The Company also recorded an income tax provision in its Statement of Comprehensive Income of $1.4 million for both the three and six months ended June 30, 2014 in connection with the Company’s unrealized gain on “available-for-sale” marketable securities. For both the three and six months ended June 30, 2013, no such income tax provision or benefit was required in connection with the Company’s unrealized losses on “available-for-sale” marketable securities.
	Tax years subsequent to 2009 remain open to examination by federal tax authorities. The Company's 2011 federal income tax return is currently under audit by the Internal Revenue Service. During the second quarter of 2014, New York State tax authorities finalized their audit of the Company's 2009, 2010, and 2011 business corporation franchise tax returns with no adjustments.

Statement_of_Cash_Flows_Notes

Statement of Cash Flows (Notes)	6 Months Ended
	Jun. 30, 2014
Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract]	'
Statement of Cash Flows	'
	Statement of Cash Flows
	Supplemental disclosure of non-cash investing and financing activities:
	Included in accounts payable and accrued expenses at June 30, 2014 and December 31, 2013 were $35.1 million and $16.1 million, respectively, of accrued capital expenditures. Included in accounts payable and accrued expenses at June 30, 2013 and December 31, 2012 were $8.1 million and $8.6 million, respectively, of accrued capital expenditures.
	Pursuant to the application of authoritative guidance issued by the Financial Accounting Standards Board ("FASB") to the Company's lease of office and laboratory facilities in Tarrytown, New York, the Company recognized a facility lease obligation of $50.6 million and $4.7 million during the six months ended June 30, 2014 and 2013, respectively, in connection with capitalizing, on the Company's books, the landlord's costs of constructing new facilities that the Company has leased.

Legal_Matters_Notes

Legal Matters (Notes)	6 Months Ended
	Jun. 30, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Legal Matters	'
	Legal Matters
	From time to time, the Company is a party to legal proceedings in the course of the Company's business. The Company does not expect any such current legal proceedings to have a material adverse effect on the Company's business or financial condition. Costs associated with the Company's involvement in legal proceedings are expensed as incurred.
	Proceedings Relating to ‘287 Patent and '018 Patent
	The Company is a party to patent infringement litigation involving its European Patent No. 1,360,287 (the "'287 Patent") and its U.S. Patent No. 8,502,018 (the "'018 Patent"), both of which concern genetically altered mice capable of producing chimeric antibodies that are part human and part mouse. Chimeric antibody sequences can be used to produce high-affinity fully human monoclonal antibodies. In these proceedings (the "'287 Patent Infringement Litigation" and "'018 Patent Infringement Litigation," respectively), the Company claims infringement of several claims of the '287 Patent and the '018 Patent (as applicable), and seeks, among other types of relief, an injunction and an account of profits in connection with the defendants' infringing acts, which may include, among other things, the making, use, keeping, sale, or offer for sale of genetically engineered mice (or certain cells from which they are derived) that infringe one or more claims of the '287 Patent and the '018 Patent (as applicable).
	As the '287 Patent Infringement Litigation and '018 Patent Infringement Litigation proceedings are at an early stage, at this time the Company is not able to predict the outcome of, or an estimate of gain, if any, related to, these proceedings.

Recently_Issued_Accounting_Sta

Recently Issued Accounting Standards (Notes)	6 Months Ended
	Jun. 30, 2014
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]	'
Description of New Accounting Pronouncements Not yet Adopted [Text Block]	'
	Recently Issued Accounting Standards
	In May 2014, the FASB issued a new standard related to revenue recognition, Revenue from Contracts with Customers, which will replace existing revenue recognition guidance. The new standard requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. To achieve that core principle, an entity must identify the contract(s) with a customer, identify the performance obligations in the contract, determine the transaction price, allocate the transaction price to the performance obligations in the contract, and recognize revenue when (or as) the entity satisfies the performance obligation. The new standard will be effective for annual and interim reporting periods beginning after December 15, 2016, and early adoption is not permitted. The standard allows for two transition methods - retrospectively to each prior reporting period presented or retrospectively with the cumulative effect of initially applying the standard recognized at the date of initial adoption. The Company has not yet determined its method of transition and is evaluating the impact that this guidance will have on the Company's financial statements.

Subsequent_Events_Notes

Subsequent Events (Notes)	6 Months Ended
	Jun. 30, 2014
Subsequent Events [Abstract]	'
Subsequent Events	'
	Subsequent Events
	In July 2014, in connection with the Company’s antibody collaboration with Sanofi (see Note 3), the Company purchased an FDA priority review voucher from a third party for $67.5 million. The Company and Sanofi will equally share the priority review voucher's purchase price.

Net_Product_Sales_Policies

Net Product Sales (Policies)	6 Months Ended
	Jun. 30, 2014
Revenues [Abstract]	'
Revenue Recognition, Revenue Reductions [Policy Text Block]	'
	Revenue from product sales is recorded net of applicable provisions for rebates and chargebacks under governmental programs (including Medicaid), distribution-related fees, prompt pay discounts, and other sales-related deductions.

Legal_Matters_Policies

Legal Matters (Policies)	6 Months Ended
	Jun. 30, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Legal Costs, Policy [Policy Text Block]	'
	Costs associated with the Company's involvement in legal proceedings are expensed as incurred.

Net_Product_Sales_Tables

Net Product Sales (Tables)	6 Months Ended
	Jun. 30, 2014
Revenues [Abstract]	'
Sales Related Deductions Activity	'
	The following table summarizes the provisions, and credits/payments, for these sales-related deductions during the six months ended June 30, 2014.
		Rebates &			Distribution-			Other Sales-			Total
		Chargebacks			Related			Related
					Fees			Deductions
	Balance as of December 31, 2013	$	4,400		$	19,663		$	538		$	24,601
	Provision related to current period sales	14,817			36,206			818			51,841
	Credits/payments	(15,077		)	(35,449		)	(834		)	(51,360		)
	Balance as of June 30, 2014	$	4,140		$	20,420		$	522		$	25,082

Collaboration_Agreements_Table

Collaboration Agreements (Tables)	6 Months Ended
	Jun. 30, 2014
Collaboration Agreement [Abstract]	'
Collaboration revenue with related party	'
	The collaboration revenue the Company earned from Sanofi, as detailed below, consisted primarily of reimbursement for research and development expenses that the Company incurred in connection with the companies' antibody collaboration. In addition, Sanofi collaboration revenue for the three months and six months ended June 30, 2013 was reduced by two $10.0 million up-front payments to Sanofi in connection with the Company's acquisition from Sanofi of full exclusive rights to two families of novel antibodies, as described below.
		Three months ended
		June 30,
	Sanofi Collaboration Revenue	2014			2013
	ZALTRAP:
	Regeneron's share of losses in connection with commercialization of ZALTRAP	$	(692	)	$	(8,216	)
	Reimbursement of Regeneron research and development expenses	1,338			1,992
	Other	1,484			2,227
	Total ZALTRAP	2,130			(3,997		)
	Antibody:
	Reimbursement of Regeneron research and development expenses	137,893			105,274
	Regeneron's share of commercialization expenses	(4,295		)	—
	Up-front payments to Sanofi for acquisition of rights related to two antibodies	—			(20,000		)
	Other	6,867			4,252
	Total Antibody	140,465			89,526
	Total Sanofi collaboration revenue	$	142,595		$	85,529
		Six months ended
		June 30,
	Sanofi Collaboration Revenue	2014			2013
	ZALTRAP:
	Regeneron's share of losses in connection with commercialization of ZALTRAP	$	(3,904	)	$	(16,005	)
	Reimbursement of Regeneron research and development expenses	2,430			4,081
	Other	3,661			4,084
	Total ZALTRAP	2,187			(7,840		)
	Antibody:
	Reimbursement of Regeneron research and development expenses	264,715			204,898
	Regeneron's share of commercialization expenses	(4,295		)	—
	Up-front payments to Sanofi for acquisition of rights related to two antibodies	—			(20,000		)
	Other	10,496			7,744
	Total Antibody	270,916			192,642
	Total Sanofi collaboration revenue	$	273,103		$	184,802
Collaboration revenue	'
	The collaboration revenue the Company earned from Bayer HealthCare is detailed below:
		Three months ended
		June 30,
	Bayer HealthCare Collaboration Revenue	2014			2013
	EYLEA:
	Regeneron's net profit in connection with commercialization of EYLEA outside the United States	$	66,781		$	19,055
	Sales milestones	15,000			—
	Cost-sharing of Regeneron EYLEA development expenses	1,494			3,629
	Other	10,813			8,420
	Total EYLEA	94,088			31,104
	PDGFR-beta antibody:
	Cost-sharing of REGN2176-3 development expenses	626			—
	Other	2,581			—
	Total PDGFR-beta	3,207			—
	Total Bayer HealthCare collaboration revenue	$	97,295		$	31,104
		Six months ended
		June 30,
	Bayer HealthCare Collaboration Revenue	2014			2013
	EYLEA:
	Regeneron's net profit in connection with commercialization of EYLEA outside the United States	$	127,940		$	25,417
	Sales milestones	45,000			—
	Cost-sharing of Regeneron EYLEA development expenses	21,841			9,466
	Other	21,745			11,128
	Total EYLEA	216,526			46,011
	PDGFR-beta antibody:
	Cost-sharing of REGN2176-3 development expenses	1,139			—
	Other	4,942			—
	Total PDGFR-beta	6,081			—
	Total Bayer HealthCare collaboration revenue	$	222,607		$	46,011

Net_Income_Per_Share_Tables

Net Income Per Share (Tables)	6 Months Ended
	Jun. 30, 2014
Earnings Per Share [Abstract]	'
Basic and Diluted Net Income (Loss) Per Share	'
	The calculations of basic and diluted net income per share are as follows:
		Three months ended June 30,
		2014			2013
	Net income - basic and diluted	$	92,735		$	87,376
	(Shares in thousands)
	Weighted average shares - basic	100,391			97,700
	Effect of dilutive securities:
	Stock options	9,359			10,291
	Restricted stock	405			424
	Warrants	2,877			2,645
	Dilutive potential shares	12,641			13,360
	Weighted average shares - diluted	113,032			111,060
	Net income per share - basic	$	0.92		$	0.89
	Net income per share - diluted	$	0.82		$	0.79
		Six months ended June 30,
		2014			2013
	Net income - basic and diluted	$	158,178		$	186,250
	(Shares in thousands)
	Weighted average shares - basic	100,085			97,289
	Effect of dilutive securities:
	Stock options	9,615			10,296
	Restricted stock	403			383
	Warrants	3,018			2,337
	Dilutive potential shares	13,036			13,016
	Weighted average shares - diluted	113,121			110,305
	Net income per share - basic	$	1.58		$	1.91
	Net income per share - diluted	$	1.4		$	1.69
Antidilutive Securities	'
	Shares which have been excluded from the June 30, 2014 and 2013 diluted per share amounts because their effect would have been antidilutive include the following:
		Three months ended June 30,
	(Shares in thousands)	2014		2013
	Stock options	3,765		1,247
	Convertible senior notes	4,662		4,761
		Six months ended June 30,
	(Shares in thousands)	2014		2013
	Stock options	3,714		3,599
	Convertible senior notes	4,711		4,761

Marketable_Securities_Tables

Marketable Securities (Tables)	6 Months Ended
	Jun. 30, 2014
Investments, Debt and Equity Securities [Abstract]	'
Available-for-sale Securities	'
	The following tables summarize the Company's investments in marketable securities at June 30, 2014 and December 31, 2013.
			Amortized			Unrealized						Fair
	At June 30, 2014		Cost Basis			Gains			Losses			Value
	U.S. government and government agency obligations		$	52,071		$	97		—			$	52,168
	Corporate bonds		647,052			1,108			$	(368	)	647,792
	Municipal bonds		46,336			190			—			46,526
	International government agency obligations		6,211			—			(1		)	6,210
	Certificates of deposit		7,920			2			—			7,922
	Equity securities		1,166			5,808			—			6,974
	Total marketable securities		$	760,756		$	7,205		$	(369	)	$	767,592
	At December 31, 2013
	U.S. government and government agency obligations		$	107,493		$	55		$	(27	)	$	107,521
	Corporate bonds		369,321			233			(361		)	369,193
	Commercial paper		23,891			53			—			23,944
	Municipal bonds		36,935			45			(59		)	36,921
	International government agency obligations		2,007			1			—			2,008
	Certificates of deposit		7,509			5			—			7,514
	Equity securities		1,166			—			—			1,166
	Total marketable securities		$	548,322		$	392		$	(447	)	$	548,267
Marketable Securities, Based on Contractual Maturity Dates	'
	The fair values of debt security investments by contractual maturity as of June 30, 2014 and December 31, 2013 consist of the following:
			June 30,			31-Dec-13
			2014
	Maturities within one year		$	216,774		$	158,376
	Maturities after one year through five years		538,647			383,410
	Maturities after five years through ten years		4,043			4,138
	Maturities after ten years		1,154			1,177
			$	760,618		$	547,101
Fair Value and Unrealized Losses of Marketable Securities	'
	The following table shows the fair value of the Company’s marketable securities that have unrealized losses and that are deemed to be only temporarily impaired, aggregated by investment category and length of time that the individual securities have been in a continuous unrealized loss position, at June 30, 2014 and December 31, 2013.
		Less than 12 Months						12 Months or Greater					Total
	At June 30, 2014	Fair Value			Unrealized Loss			Fair Value			Unrealized Loss		Fair Value		Unrealized Loss
	Corporate bonds	$	157,970		$	(368	)	—			—		$	157,970	$	(368	)
	International government agency obligations	6,210			(1		)						6,210		(1		)
		$	164,180		$	(369	)	—			—		$	164,180	$	(369	)
	At December 31, 2013
	U.S. government and government agency obligations	$	49,241		$	(27	)	—			—		$	49,241	$	(27	)
	Corporate bonds	176,140			(361		)	—			—		176,140		(361		)
	Municipal bonds	14,431			(59		)	—			—		14,431		(59		)
		$	239,812		$	(447	)	—			—		$	239,812	$	(447	)

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2014
Fair Value Disclosures [Abstract]	'
Schedule of assets measured at fair value on a recurring basis	'
	The Company’s assets that are measured at fair value on a recurring basis, at June 30, 2014 and December 31, 2013, consist of the following:
				Fair Value Measurements at Reporting Date Using
	At June 30, 2014	Fair Value		Quoted Prices in		Significant Other
				Active Markets		Observable Inputs
				for Identical		(Level 2)
				Assets
				(Level 1)
	Available-for-sale marketable securities:
	U.S. government and government agency obligations	$	52,168	—		$	52,168
	Corporate bonds	647,792		—		647,792
	Municipal bonds	46,526		—		46,526
	International government agency obligations	6,210		—		6,210
	Certificates of deposit	7,922		—		7,922
	Equity securities	6,974		$	6,974	—
		$	767,592	$	6,974	$	760,618
	At December 31, 2013
	Available-for-sale marketable securities:
	U.S. government and government agency obligations	$	107,521	—		$	107,521
	Corporate bonds	369,193		—		369,193
	Commercial paper	23,944		—		23,944
	Municipal bonds	36,921		—		36,921
	International government agency obligations	2,008		—		2,008
	Certificates of deposit	7,514		—		7,514
	Equity securities	1,166		$	1,166	—
		$	548,267	$	1,166	$	547,101

Inventory_Tables

Inventory (Tables)	6 Months Ended
	Jun. 30, 2014
Inventory Disclosure [Abstract]	'
Schedule of Inventory, Current	'
	Inventories consist of the following:
		June 30,		December 31,
		2014		2013
	Raw materials	$	10,220	$	9,120
	Work-in-process	60,110		35,868
	Finished goods	12,215		14,352
	Deferred costs	27,352		11,014
		$	109,897	$	70,354

Accounts_Payable_and_Accrued_E1

Accounts Payable and Accrued Expenses (Tables)	6 Months Ended
	Jun. 30, 2014
Payables and Accruals [Abstract]	'
Schedule of Accounts Payable and Accrued Liabilities	'
	Accounts payable and accrued expenses consist of the following:
		June 30,		December 31,
		2014		2013
	Accounts payable	$	47,231	$	61,936
	Accrued payroll and related costs	51,786		69,429
	Accrued clinical trial expense	35,498		23,654
	Accrued sales-related charges, deductions, and royalties	100,333		66,855
	Other accrued expenses and liabilities	48,537		29,022
		$	283,385	$	250,896

Net_Product_Sales_Details

Net Product Sales (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Revenue Disclosure [Line Items]	'	'	'	'	'
Net product sales	$418,022	$333,893	$780,400	$652,633	'
Activity of Sales Related Deductions [Roll Forward]	'	'	'	'	'
Balance	25,082	'	25,082	'	24,601
Provision related to current period sales	'	'	51,841	'	'
Credits/payments	'	'	-51,360	'	'
Rebates and Chargebacks	'	'	'	'	'
Activity of Sales Related Deductions [Roll Forward]	'	'	'	'	'
Balance	4,140	'	4,140	'	4,400
Provision related to current period sales	'	'	14,817	'	'
Credits/payments	'	'	-15,077	'	'
Distribution Related Fees	'	'	'	'	'
Activity of Sales Related Deductions [Roll Forward]	'	'	'	'	'
Balance	20,420	'	20,420	'	19,663
Provision related to current period sales	'	'	36,206	'	'
Credits/payments	'	'	-35,449	'	'
Other Sales Related Deductions	'	'	'	'	'
Activity of Sales Related Deductions [Roll Forward]	'	'	'	'	'
Balance	522	'	522	'	538
Provision related to current period sales	'	'	818	'	'
Credits/payments	'	'	-834	'	'
Customer concentration risk | Gross Sales Revenue	'	'	'	'	'
Risks and Uncertainties [Abstract]	'	'	'	'	'
Concentration risk, percentage	73.00%	76.00%	76.00%	77.00%	'
EYLEA	'	'	'	'	'
Revenue Disclosure [Line Items]	'	'	'	'	'
Net product sales	414,800	329,800	773,800	643,700	'
ARCALYST	'	'	'	'	'
Revenue Disclosure [Line Items]	'	'	'	'	'
Net product sales	$3,200	$4,100	$6,600	$8,900	'

Collaboration_Agreements_Sanof

Collaboration Agreements (Sanofi) (Details) (USD $)	3 Months Ended			6 Months Ended
	Jun. 30, 2014	Mar. 31, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
			family		family
Collaboration Agreement [Line Items]	'	'	'	'	'
Research and development	$294,501,000	'	$187,463,000	$581,880,000	$367,762,000
Revenue from Related Parties	142,595,000	'	85,529,000	273,103,000	184,802,000
ZALTRAP Agreement	'	'	'	'	'
Collaboration Agreement [Line Items]	'	'	'	'	'
Net profit (loss) from commercialization of products under collaboration agreement	-692,000	'	-8,216,000	-3,904,000	-16,005,000
Reimbursement of Regeneron research and development expenses	1,338,000	'	1,992,000	2,430,000	4,081,000
Contracts Revenue	1,484,000	'	2,227,000	3,661,000	4,084,000
Revenue from Related Parties	2,130,000	'	-3,997,000	2,187,000	-7,840,000
Ang2	'	'	'	'	'
Collaboration Agreement [Line Items]	'	'	'	'	'
Research and Development in Process	'	'	10,000,000	'	10,000,000
Antibody Collaboration	'	'	'	'	'
Collaboration Agreement [Line Items]	'	'	'	'	'
Net profit (loss) from commercialization of products under collaboration agreement	-4,295,000	'	0	-4,295,000	0
Number of Payments the Company made	'	2	2	'	2
Research and Development in Process	0	'	20,000,000	0	20,000,000
Number of families of novel antibodies	'	'	2	'	2
Percentage of Trial Costs borne by collaborating party	'	'	'	80.00%	'
Percentage of Trial Costs borne by entity	'	'	'	20.00%	'
Research and development	29,100,000	'	'	52,900,000	'
Other Research and Development Expense	'	5,000,000	'	5,000,000	'
Milestone payment	'	'	'	30,000,000	'
Reimbursement of Regeneron research and development expenses	137,893,000	'	105,274,000	264,715,000	204,898,000
Contracts Revenue	6,867,000	'	4,252,000	10,496,000	7,744,000
Revenue from Related Parties	140,465,000	'	89,526,000	270,916,000	192,642,000
PDGF	'	'	'	'	'
Collaboration Agreement [Line Items]	'	'	'	'	'
Research and Development in Process	'	'	$10,000,000	'	$10,000,000

Collaboration_Agreements_Bayer

Collaboration Agreements (Bayer HealthCare LLC) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Collaboration Agreement [Line Items]	'	'	'	'
Deferred Revenue, Additions	'	'	$25,500,000	'
Other Collaboration Revenue	97,295,000	31,104,000	222,607,000	46,011,000
EYLEA	'	'	'	'
Collaboration Agreement [Line Items]	'	'	'	'
Net profit (loss) from commercialization of products under collaboration agreement	66,781,000	19,055,000	127,940,000	25,417,000
Revenue Recognition, Milestone Method, Revenue Recognized	15,000,000	0	45,000,000	0
Reimbursement of Regeneron research and development expenses	1,494,000	3,629,000	21,841,000	9,466,000
Contracts Revenue	10,813,000	8,420,000	21,745,000	11,128,000
Other Collaboration Revenue	94,088,000	31,104,000	216,526,000	46,011,000
PDGFR-beta	'	'	'	'
Collaboration Agreement [Line Items]	'	'	'	'
Reimbursement of Regeneron research and development expenses	626,000	0	1,139,000	0
Deferred Revenue, Additions	2,581,000	0	4,942,000	0
Other Collaboration Revenue	$3,207,000	$0	$6,081,000	$0

Collaboration_Agreements_EYLEA

Collaboration Agreements (EYLEA) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Mar. 31, 2014	Jun. 30, 2014
Collaboration Agreement [Line Items]	'	'	'
Number of sales milestone payments the Company received	1	2	'
Levels of twelve month sales at which sales milestone payments were received - 700 million	$700,000,000	'	'
Period for Achieving Sales Target for Milestone Payment, Rolling Basis	'	'	'12 months
levels of twelve months sales at which sales milestone payments maybe received - 1 billion	'	'	1,000,000,000
levels of twelve month sales at which sales milestone payments maybe received - 200 million	'	'	200,000,000
Deferred Revenue, Additions	'	'	25,500,000
Levels of twelve month sales at which sales milestone payments were received - 500 million	'	500,000,000	'
Levels of twelve month sales at which sales milestone payments were received - 600 million	'	600,000,000	'
sales achievement - $600 million	'	'	'
Collaboration Agreement [Line Items]	'	'	'
Revenue Recognition, Milestone Method, Revenue Recognized	'	15,000,000	'
sales achievement - $500 million	'	'	'
Collaboration Agreement [Line Items]	'	'	'
Revenue Recognition, Milestone Method, Revenue Recognized	'	15,000,000	'
sales achievement - $700 million	'	'	'
Collaboration Agreement [Line Items]	'	'	'
Revenue Recognition, Milestone Method, Revenue Recognized	15,000,000	'	'
sales achievement - $1 billion	'	'	'
Collaboration Agreement [Line Items]	'	'	'
Maximum amount of sales milestone payments if total sales achieve specific levels	'	'	45,000,000
sales achievement - $200 million	'	'	'
Collaboration Agreement [Line Items]	'	'	'
Maximum amount of sales milestone payments if total sales achieve specific levels	'	'	30,000,000
BRVO	'	'	'
Collaboration Agreement [Line Items]	'	'	'
Reimbursement of Regeneron research and development expenses	'	$15,700,000	'

Collaboration_Agreements_PDGFR

Collaboration Agreements (PDGFR-beta Antibody) (Details) (USD $)	3 Months Ended	6 Months Ended
	Mar. 31, 2014	Jun. 30, 2014
Collaboration Agreement [Line Items]	'	'
Amount of non refundable payment received for collaboration agreement	'	$25,500,000
Deferred Revenue, Additions	'	25,500,000
Collaboration Agreement with Bayer HealthCare	'	'
Collaboration Agreement [Line Items]	'	'
Percentage of global development cost to be paid by the collaboration partner under the collaboration	'	25.00%
Percentage of development cost for the territory outside the United States to be paid for under the collaboration	'	50.00%
Percentage of development milestone payments to be reimbursed	'	50.00%
Number of development milestone payments the Company received	2	'
Deferred Revenue, Additions	2,500,000	'
Future development milestone payment	'	15,000,000
Opt in payment	'	20,000,000
Amount of milestone payment that may be received relating to marketing approval	'	$20,000,000

Collaboration_Agreements_Avala

Collaboration Agreements (Avalanche Biotechnologies, Inc.) (Details) (Collaboration Agreement with Avalanche Biotechnologies, inc., USD $)	6 Months Ended		1 Months Ended
In Millions, except Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2014	Jul. 31, 2014
		Per Product	Subsequent Event
Collaboration Agreement [Line Items]	'	'	'
Research and Development Asset Acquired Other than Through Business Combination, Written-off	$2	'	'
Pre-payment of collaboration research costs	6	'	'
Potential future milestone payments	640	80	'
Number of therapeutic targets	8	'	'
Payment to acquire preferred share of non-public entity	5	'	'
Number of therapeutic targets of Avalanche's choice	2	'	'
Payment to acquire common stock from public entity	'	'	$10
Number of shares of Common Stock to be purchased	'	'	588,235

Net_Income_Per_Share_Details

Net Income Per Share (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Earnings Per Share [Abstract]	'	'	'	'
Net income	$92,735	$87,376	$158,178	$186,250
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]	'	'	'	'
Weighted average shares outstanding - basic	100,391	97,700	100,085	97,289
Effect of dilutive securities (in shares):	'	'	'	'
Stock options	9,359	10,291	9,615	10,296
Restricted stock	405	424	403	383
Warrants	2,877	2,645	3,018	2,337
Dilutive potential shares	12,641	13,360	13,036	13,016
Weighted average shares - diluted (in shares)	113,032	111,060	113,121	110,305
Earnings Per Share, Basic and Diluted [Abstract]	'	'	'	'
Net income per share - basic	$0.92	$0.89	$1.58	$1.91
Net income per share - diluted (in dollars per share)	$0.82	$0.79	$1.40	$1.69
Stock options	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Weighted average number of shares	3,765	1,247	3,714	3,599
Convertible senior notes	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Weighted average number of shares	4,662	4,761	4,711	4,761

Marketable_Securities_Details

Marketable Securities (Details) (USD $)	3 Months Ended	6 Months Ended		12 Months Ended
	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'
Available for sale securities, realized gain	$500,000	'	$500,000	'
Available for sale securities, realized loss	0	'	0	'
Amortized Cost Basis	'	760,756,000	'	548,322,000
Unrealized Gains	'	7,205,000	'	392,000
Unrealized (Losses)	'	-369,000	'	-447,000
Total fair value of available-for-sale marketable securities	'	767,592,000	'	548,267,000
Available-for-sale Securities, Debt Maturities, Fair Value [Abstract]	'	'	'	'
Maturities within one year	'	216,774,000	'	158,376,000
Maturities after one year through five years	'	538,647,000	'	383,410,000
Maturities after five years through ten years	'	4,043,000	'	4,138,000
Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value	'	1,154,000	'	1,177,000
Total	'	760,618,000	'	547,101,000
Continuous Unrealized Loss Position, Fair Value [Abstract]	'	'	'	'
Fair Value - Less than 12 Months	'	164,180,000	'	239,812,000
Fair Value - 12 Months or Greater	'	0	'	0
Fair Value - Total	'	164,180,000	'	239,812,000
Continuous Unrealized Loss Position, Aggregate Losses [Abstract]	'	'	'	'
Unrealized Loss - Less than 12 months	'	-369,000	'	-447,000
Unrealized Loss - 12 Months or Greater	'	0	'	0
Unrealized Loss - Total	'	-369,000	'	-447,000
U.S. government and government agency obligations	'	'	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'
Amortized Cost Basis	'	52,071,000	'	107,493,000
Unrealized Gains	'	97,000	'	55,000
Unrealized (Losses)	'	0	'	-27,000
Total fair value of available-for-sale marketable securities	'	52,168,000	'	107,521,000
Continuous Unrealized Loss Position, Fair Value [Abstract]	'	'	'	'
Fair Value - Less than 12 Months	'	'	'	49,241,000
Fair Value - Total	'	'	'	49,241,000
Continuous Unrealized Loss Position, Aggregate Losses [Abstract]	'	'	'	'
Unrealized Loss - Less than 12 months	'	'	'	-27,000
Unrealized Loss - Total	'	'	'	-27,000
Corporate bonds	'	'	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'
Amortized Cost Basis	'	647,052,000	'	369,321,000
Unrealized Gains	'	1,108,000	'	233,000
Unrealized (Losses)	'	-368,000	'	-361,000
Total fair value of available-for-sale marketable securities	'	647,792,000	'	369,193,000
Continuous Unrealized Loss Position, Fair Value [Abstract]	'	'	'	'
Fair Value - Less than 12 Months	'	157,970,000	'	176,140,000
Fair Value - Total	'	157,970,000	'	176,140,000
Continuous Unrealized Loss Position, Aggregate Losses [Abstract]	'	'	'	'
Unrealized Loss - Less than 12 months	'	-368,000	'	-361,000
Unrealized Loss - Total	'	-368,000	'	-361,000
Commercial Paper	'	'	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'
Amortized Cost Basis	'	'	'	23,891,000
Unrealized Gains	'	'	'	53,000
Unrealized (Losses)	'	'	'	0
Total fair value of available-for-sale marketable securities	'	'	'	23,944,000
Municipal bonds	'	'	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'
Amortized Cost Basis	'	46,336,000	'	36,935,000
Unrealized Gains	'	190,000	'	45,000
Unrealized (Losses)	'	0	'	-59,000
Total fair value of available-for-sale marketable securities	'	46,526,000	'	36,921,000
Continuous Unrealized Loss Position, Fair Value [Abstract]	'	'	'	'
Fair Value - Less than 12 Months	'	'	'	14,431,000
Fair Value - Total	'	'	'	14,431,000
Continuous Unrealized Loss Position, Aggregate Losses [Abstract]	'	'	'	'
Unrealized Loss - Less than 12 months	'	'	'	-59,000
Unrealized Loss - Total	'	'	'	-59,000
International government agency obligations	'	'	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'
Amortized Cost Basis	'	6,211,000	'	2,007,000
Unrealized Gains	'	0	'	1,000
Unrealized (Losses)	'	-1,000	'	0
Total fair value of available-for-sale marketable securities	'	6,210,000	'	2,008,000
Continuous Unrealized Loss Position, Fair Value [Abstract]	'	'	'	'
Fair Value - Less than 12 Months	'	6,210,000	'	'
Fair Value - Total	'	6,210,000	'	'
Continuous Unrealized Loss Position, Aggregate Losses [Abstract]	'	'	'	'
Unrealized Loss - Less than 12 months	'	-1,000	'	'
Unrealized Loss - Total	'	-1,000	'	'
Certificates of Deposit	'	'	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'
Amortized Cost Basis	'	7,920,000	'	7,509,000
Unrealized Gains	'	2,000	'	5,000
Unrealized (Losses)	'	0	'	0
Total fair value of available-for-sale marketable securities	'	7,922,000	'	7,514,000
Equity Securities	'	'	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'
Amortized Cost Basis	'	1,166,000	'	1,166,000
Unrealized Gains	'	5,808,000	'	0
Unrealized (Losses)	'	0	'	0
Total fair value of available-for-sale marketable securities	'	$6,974,000	'	$1,166,000

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (USD $)

Jun. 30, 2014

Dec. 31, 2013

Jun. 30, 2014

Dec. 31, 2013

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

Dec. 31, 2013

Jun. 30, 2014

Dec. 31, 2013

Jun. 30, 2014

Dec. 31, 2013

Convertible senior notes

Convertible senior notes

Significant Other Observable Inputs (Level 2)

Significant Other Observable Inputs (Level 2)

Significant Other Observable Inputs (Level 2)

Significant Other Observable Inputs (Level 2)

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 3 [Member]

Measured on a recurring basis

Measured on a recurring basis

Measured on a recurring basis

Measured on a recurring basis

Measured on a recurring basis

Measured on a recurring basis

Fair Value

Fair Value

Quoted Prices in Active Markets for Identical Assets (Level 1)

Quoted Prices in Active Markets for Identical Assets (Level 1)

Significant Other Observable Inputs (Level 2)

Significant Other Observable Inputs (Level 2)

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Other than Temporary Impairment Losses, Investments

'

'

'

'

$0

$0

$0

$0

'

'

'

'

'

'

'

'

'

'

Marketable Securities, Unrealized Gain (Loss)

'

'

'

'

'

'

'

'

0

0

0

0

'

'

'

'

'

'

Debt Instrument, Face Amount

'

400,000,000

338,900,000

400,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Available-for-sale marketable securities:

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

U.S. government and government agency obligations

'

'

'

'

'

'

'

'

'

'

'

'

52,168,000

107,521,000

'

'

52,168,000

107,521,000

Corporate bonds

'

'

'

'

'

'

'

'

'

'

'

'

647,792,000

369,193,000

'

'

647,792,000

369,193,000

Commercial paper

'

'

'

'

'

'

'

'

'

'

'

'

'

23,944,000

'

'

'

23,944,000

Municipal bonds

'

'

'

'

'

'

'

'

'

'

'

'

46,526,000

36,921,000

'

'

46,526,000

36,921,000

International government agency obligations

'

'

'

'

'

'

'

'

'

'

'

'

6,210,000

2,008,000

'

'

6,210,000

2,008,000

Certificates of deposit

'

'

'

'

'

'

'

'

'

'

'

'

7,922,000

7,514,000

'

'

7,922,000

7,514,000

Equity securities

'

'

'

'

'

'

'

'

'

'

'

'

6,974,000

1,166,000

6,974,000

1,166,000

'

'

Total fair value of available-for-sale marketable securities

767,592,000

548,267,000

'

'

'

'

'

'

'

'

'

'

767,592,000

548,267,000

6,974,000

1,166,000

760,618,000

547,101,000

Convertible Debt [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Interest rate, stated percentage

'

'

1.88%

1.88%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Fair value of the outstanding notes

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$1,090,800,000

$1,327,200,000

Inventory_Schedule_of_Inventor

Inventory (Schedule of Inventory) (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Inventory Disclosure [Abstract]	'	'
Raw materials	$10,220	$9,120
Work in process	60,110	35,868
Finished goods	12,215	14,352
Deferred costs	27,352	11,014
Total Inventories	$109,897	$70,354

Inventory_Narrative_Details

Inventory (Narrative) (Details) (USD $)	3 Months Ended		6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Inventory Disclosure [Abstract]	'	'	'	'
Inventory write-downs and reserves	$0.80	$1.70	$1.90	$4.90

Accounts_Payable_and_Accrued_E2

Accounts Payable and Accrued Expenses (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Accounts Payable and Accrued Liabilities, Current [Abstract]	'	'
Accounts payable	$47,231	$61,936
Accrued payroll and related costs	51,786	69,429
Accrued clinical trial expense	35,498	23,654
Accrued sales-related charges, deductions and royalties	100,333	66,855
Other accrued expenses and liabilities	48,537	29,022
Accounts payable and accrued expenses	$283,385	$250,896

Convertible_Debt_Details

Convertible Debt (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Mar. 31, 2014	Dec. 31, 2013
Debt Disclosure [Abstract]	'	'	'	'	'	'
Debt Conversion	'	'	$61,100,000	'	'	'
Debt Instrument, Face Amount	'	'	'	'	'	400,000,000
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'	'	'
Repayments of Convertible Debt	'	'	61,125,000	0	'	'
Issuance of Common Stock in connection with conversion of convertible senior notes (in shares)	'	'	521,876	'	'	'
Gains (Losses) on Extinguishment of Debt	-10,787,000	0	-10,787,000	0	'	'
Stock Issued During Period, Shares, Acquisitions	'	'	521,876	'	'	'
Payments for Repurchase of Warrants	'	'	143,041,000	0	'	'
Maximum number of shares issuable upon exercise of warrants	4,033,324	'	4,033,324	'	4,760,840	'
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt, Subsequent Adjustments	'	'	($156,651,000)	'	'	'

Income_Taxes_Details

Income Taxes (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Components of Income Tax Expense (Benefit), Continuing Operations [Abstract]	'	'	'	'
Total income tax expense (benefit)	$110,384,000	$60,316,000	$220,204,000	$103,273,000
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]	'	'	'	'
Effective income tax rate	54.30%	40.80%	58.20%	35.70%
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent	'	'	0.00%	'
Effective Income Tax Rate Reconciliation, Change in Tax Rates, Percent	'	'	3.90%	'
Operating Loss Carryforwards [Line Items]	'	'	'	'
Effective Income Tax Rate Reconciliation, Tax Credit, Research, Percent	'	'	'	6.00%
Available-for-sale Securities, Income Tax Expense on Change in Unrealized Holding Gain (Loss)	$1,400,000	$0	$1,100,000	$0

Statement_of_Cash_Flows_Detail

Statement of Cash Flows (Details) (USD $)	6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Dec. 31, 2012
Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract]	'	'	'	'
Accrued capital expenditures	$35.10	$8.10	$16.10	$8.60
Facility lease obligation recognized during the period	$50.60	$4.70	'	'

Subsequent_Events_Details

Subsequent Events (Details) (Subsequent Event, USD $)	1 Months Ended
In Millions, unless otherwise specified	Jul. 31, 2014
Subsequent Event	'
Subsequent Event [Line Items]	'
Payments for Purchase of Other Assets	$67.50