View Filing Data

Three months ended March 31,

(Shares in thousands)

Stock options

Convertible senior notes

Document and Entity Information - shares	3 Months Ended
Document and Entity Information - shares	Mar. 31, 2014	Apr. 17, 2014
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	Mar. 31, 2014
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	Q1
Amendment Flag	false
Common Stock
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		98,879,794
Class A Stock
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		2,000,781

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 461,858	$ 535,608
Marketable securities	186,275	158,376
Accounts receivable - trade, net	801,773	787,071
Accounts Receivable from Sanofi	118,003	104,707
Accounts receivable from Bayer HealthCare	127,720	63,189
Inventories	86,545	70,354
Deferred tax assets	36,623	44,677
Prepaid expenses and other current assets	52,252	32,952
Total current assets	1,871,049	1,796,934
Marketable securities	534,689	389,891
Property, plant, and equipment, at cost, net of accumulated depreciation and amortization	600,864	526,983
Deferred tax assets	248,454	231,878
Other assets	5,340	5,327
Total assets	3,260,396	2,951,013
Current liabilities:
Accounts payable and accrued expenses	237,935	250,896
Deferred revenue from Sanofi, current portion	12,980	12,815
Deferred Revenue - other, current portion	53,093	34,185
Facility Lease Obligations, Current	1,060	939
Total current liabilities	305,068	298,835
Deferred revenue from Sanofi	73,694	76,522
Deferred Revenue - other	128,539	107,677
Facility lease obligations	203,380	184,258
Convertible senior notes	326,673	320,315
Other long-term liabilities	11,794	11,330
Total liabilities	1,049,148	998,937
Stockholders' equity:
Preferred Stock	0	0
Additional paid-in capital	2,236,931	2,045,857
Accumulated deficit	(27,249)	(92,692)
Accumulated other comprehensive income (loss)	1,465	(1,188)
Total stockholders' equity	2,211,248	1,952,076
Total liabilities and stockholders' equity	3,260,396	2,951,013
Class A Stock
Stockholders' equity:
Common stock	2	2
Common Stock
Stockholders' equity:
Common stock	$ 99	$ 97

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Mar. 31, 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
Class A Stock
Stockholders' equity:
Common Stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common Stock, shares authorized (in shares)	40,000,000	40,000,000
Common Stock, shares issued (in shares)	2,000,781	2,020,481
Common Stock, shares outstanding (in shares)	2,000,781	2,020,481
Common Stock
Stockholders' equity:
Common Stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common Stock, shares authorized (in shares)	160,000,000	160,000,000
Common Stock, shares issued (in shares)	98,847,729	97,666,814
Common Stock, shares outstanding (in shares)	98,847,729	97,666,814

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Revenues:
Net product sales	$ 362,378	$ 318,740
Sanofi collaboration revenue	130,508	99,273
Bayer HealthCare collaboration revenue	125,312	14,907
Technology licensing and other revenue	7,542	6,744
Total revenues	625,740	439,664
Expenses:
Research and development	287,379	180,299
Selling, general, and administrative	108,850	77,260
Cost of goods sold	27,473	28,021
Cost of collaboration manufacturing	16,099	1,034
Total expenses	439,801	286,614
Income from operations	185,939	153,050
Other income (expense):
Investment income	937	456
Interest expense	(11,613)	(11,675)
Total other income (expense)	(10,676)	(11,219)
Income before income taxes	175,263	141,831
Income tax expense	(109,820)	(42,957)
Net income	$ 65,443	$ 98,874
Net income per share - basic	$ 0.66	$ 1.02
Net income per share - diluted	$ 0.58	$ 0.90
Weighted average shares outstanding - basic	98,709	96,878
Weighted average shares outstanding - diluted	112,151	109,369
Statements of Comprehensive Income
Net income	$ 65,443	$ 98,874
Other comprehensive income (loss):
Unrealized gain (loss) on marketable securities	2,653	(478)
Comprehensive income	$ 68,096	$ 98,396

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Class A Stock	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Balance at Dec. 31, 2012	$ 1,245,385	$ 2	$ 95	$ 1,763,508	$ (517,054)	$ (1,166)
Balance (shares) at Dec. 31, 2012		2,069	95,223
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Common Stock in connection with exercise of stock options	9,804		$ 0	9,804
Issuance of Common Stock in connection with exercise of stock options (shares)			396
Common Stock tendered upon exercise of stock options in connection with employee tax obligations	(3,085)		$ 0	(3,085)
Common Stock tendered upon exercise of stock options in connection with employee tax obligations (in shares)			(17)
Issuance of Common Stock in connection with Company 401(k) Savings Plan contribution	0
Issuance of Common Stock in connection with Company 401(k) Savings Plan contribution (shares)			38
Conversion of Class A Stock to Common Stock (shares)		(11)	11
Stock-based compensation charges	53,555			53,555
Excess tax benefit from stock-based compensation	2,293			2,293
Net income	98,874
Other comprehensive income (loss)	(478)					(478)
Balance at Mar. 31, 2013	1,406,348	$ 2	$ 95	1,826,075	(418,180)	(1,644)
Balance (shares) at Mar. 31, 2013		2,058	95,651
Balance at Dec. 31, 2013	1,952,076	$ 2	$ 97	2,045,857	(92,692)	(1,188)
Balance (shares) at Dec. 31, 2013		2,020	97,667
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Common Stock in connection with exercise of stock options	53,920		$ 2	53,918
Issuance of Common Stock in connection with exercise of stock options (shares)			1,338
Common Stock tendered upon exercise of stock options in connection with employee tax obligations	(63,086)		$ 0	(63,086)
Common Stock tendered upon exercise of stock options in connection with employee tax obligations (in shares)			(198)
Issuance of Common Stock in connection with Company 401(k) Savings Plan contribution	0
Issuance of Common Stock in connection with Company 401(k) Savings Plan contribution (shares)			21
Conversion of Class A Stock to Common Stock (shares)		(20)	20
Stock-based compensation charges	82,982			82,982
Excess tax benefit from stock-based compensation	117,260			117,260
Net income	65,443				65,443
Other comprehensive income (loss)	2,653					2,653
Balance at Mar. 31, 2014	$ 2,211,248	$ 2	$ 99	$ 2,236,931	$ (27,249)	$ 1,465
Balance (shares) at Mar. 31, 2014		2,000	98,848

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Cash flows from operating activities:
Net income	$ 65,443	$ 98,874
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	11,530	9,407
Non-cash compensation expense	81,408	53,030
Non-cash interest expense	5,916	5,781
Other non-cash charges and expenses, net	3,761	7,174
Deferred taxes	(8,522)	39,525
Changes in assets and liabilites
Increase in Sanofi, Bayer HealthCare, and trade accounts receivable	(92,529)	(117,782)
Increase in Inventories	(15,550)	(17,581)
Increase in prepaid expenses and other assets	(20,898)	(17,815)
Increase (decrease) in deferred revenue	37,107	(6,470)
(Decrease) increase in accounts payable, accrued expenses and other liabilities	(14,139)	32,105
Total adjustments	(11,916)	(12,626)
Net cash provided by operating activities	53,527	86,248
Cash flows from investing activities:
Purchases of marketable securities	(253,878)	(181,236)
Sales or maturities of marketable securities	82,469	54,754
Capital expenditures	(64,822)	(21,203)
Net cash used in investing activities	(236,231)	(147,685)
Cash flows from financing activities:
Payments in connection with facility and capital lease obligations	(262)	(649)
Proceeds from issuance of Common Stock	55,042	12,964
Payments in connection with Common Stock tendered for employee tax obligations	(63,086)	(3,085)
Excess tax benefit from stock-based compensation	117,260	2,293
Net cash provided by financing activities	108,954	11,523
Net decrease in cash and cash equivalents	(73,750)	(49,914)
Cash and cash equivalents at beginning of period	535,608	230,276
Cash and cash equivalents at end of period	$ 461,858	$ 180,362

Interim Financial Statements	3 Months Ended
Interim Financial Statements	Mar. 31, 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.

- Definition

The entire disclosure for organization, consolidation and basis of presentation of financial statements disclosure.

+ References

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+ Details

Net Product Sales

3 Months Ended

Mar. 31, 2014

Revenues [Abstract]

Net Product Sales

EYLEA^® net product sales in the United States totaled $359.0 million and $313.9 million for the three months ended March 31, 2014 and 2013, respectively. In addition, ARCALYST^® net product sales totaled $3.4 million and $4.8 million for the three months ended March 31, 2014 and 2013, respectively.

For the three months ended March 31, 2014 and 2013, the Company recorded 79% and 77%, 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 three months ended March 31, 2014.



	Rebates & Chargebacks			Distribution- Related Fees			Other Sales- Related Deductions			Total
Balance as of December 31, 2013	$	4,400		$	19,663		$	538		$	24,601
Provision related to current period sales	6,886			16,858			448			24,192
Credits/payments	(6,664		)	(16,310		)	(454		)	(23,428		)
Balance as of March 31, 2014	$	4,622		$	20,211		$	532		$	25,365

Collaboration Agreements

3 Months Ended

Mar. 31, 2014

Research and Development Arrangement, Contract to Perform for Others [Line Items]

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, the Company's share of losses in connection with Sanofi's commercialization of ZALTRAP^®, and revenue related to non-refundable up-front payments.



	Three months ended March 31,
Sanofi Collaboration Revenue	2014			2013
ZALTRAP:
Regeneron's share of losses in connection with commercialization of ZALTRAP	$	(3,212	)	$	(7,789	)
Reimbursement of Regeneron research and development expenses	1,092			2,089
Other	2,177			1,858
Total ZALTRAP	57			(3,842		)
Antibody:
Reimbursement of Regeneron research and development expenses	126,822			99,623
Other	3,629			3,492
Total Antibody	130,451			103,115
Total Sanofi collaboration revenue	$	130,508		$	99,273

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, in the first quarter of 2014, the Company recognized as additional research and development expense $23.8 million of antibody development expenses that the Company was obligated to reimburse to Sanofi related to alirocumab and sarilumab.

In May 2013, the Company acquired from Sanofi full exclusive rights to antibodies targeting the platelet derived growth factor (PDGF) family of receptors. At the time of acquisition, antibodies to the PDGF receptor were in preclinical development for use in ophthalmology. 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, and is obligated to pay up to $30.0 million in additional potential development milestones as well as royalties on any future sales.

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 March 31,
Bayer HealthCare Collaboration Revenue	2014		2013
EYLEA:
Regeneron's net profit in connection with commercialization of EYLEA outside the United States	$	61,159	$	6,362
Sales milestones	30,000		—
Cost-sharing of Regeneron EYLEA development expenses	20,347		5,888
Other	10,932		2,657
Total EYLEA	122,438		14,907
PDGFR-beta antibody:
Cost-sharing of REGN2176-3 development expenses	513		—
Other	2,361		—
Total PDGFR-beta	2,874		—
Total Bayer HealthCare collaboration revenue	$	125,312	$	14,907

EYLEA

In the first quarter of 2014, the Company earned, and recorded as revenue, two $15.0 million sales milestones from Bayer HealthCare upon total aggregate net sales of EYLEA outside the United States exceeding $500 million and $600 million, respectively, over a twelve-month period. The Company is eligible to receive up to $60.0 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" in the table above. In addition, all future agreed upon global EYLEA development expenses incurred in connection with BRVO will be 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, they 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.

Net Income Per Share

3 Months Ended

Mar. 31, 2014

Earnings Per Share [Abstract]

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 March 31,
	2014		2013
Net income - basic and diluted	$	65,443	$	98,874

(Shares in thousands)
Weighted average shares - basic	98,709		96,878
Effect of dilutive securities:
Stock options	9,879		10,276
Restricted stock	401		325
Warrants	3,162		1,890
Dilutive potential shares	13,442		12,491
Weighted average shares - diluted	112,151		109,369

Net income per share - basic	$	0.66	$	1.02
Net income per share - diluted	$	0.58	$	0.90

Shares which have been excluded from the March 31, 2014 and 2013 diluted per share amounts because their effect would have been antidilutive, include the following:

Marketable Securities

3 Months Ended

Mar. 31, 2014

Investments, Debt and Equity Securities [Abstract]

Marketable Securities

Marketable securities at March 31, 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 March 31, 2014 and December 31, 2013.



	Amortized		Unrealized					Fair
At March 31, 2014	Cost Basis		Gains		Losses			Value
U.S. government and government agency obligations	$	78,196	$	82	$	(13	)	$	78,265
Corporate bonds	579,600		517		(489		)	579,628
Municipal bonds	43,276		138		(13		)	43,401
International government agency obligations	8,214		3		—			8,217
Certificates of deposit	7,914		4		—			7,918
Equity securities	1,166		2,369		—			3,535
Total marketable securities	$	718,366	$	3,113	$	(515	)	$	720,964

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 March 31, 2014 mature at various dates through August 2024. The fair values of debt security investments by contractual maturity as of March 31, 2014 and December 31, 2013 consist of the following:



	March 31, 2014		December 31, 2013
Maturities within one year	$	186,275	$	158,376
Maturities after one year through five years	525,961		383,410
Maturities after five years through ten years	4,042		4,138
Maturities after ten years	1,151		1,177
	$	717,429	$	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 March 31, 2014 and December 31, 2013.



	Less than 12 Months					12 Months or Greater		Total
At March 31, 2014	Fair Value		Unrealized Loss			Fair Value	Unrealized Loss	Fair Value		Unrealized Loss
U.S. government and government agency obligations	$	5,983	$	(13	)	—	—	$	5,983	$	(13	)
Corporate bonds	268,174		(489		)	—	—	268,174		(489		)
Municipal bonds	12,187		(13		)	—	—	12,187		(13		)
	$	286,344	$	(515	)	—	—	$	286,344	$	(515	)

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 the three months ended March 31, 2014 and 2013, total realized gains and losses on sales of marketable securities were not material. Changes in the Company's accumulated other comprehensive income (loss) for the three months ended March 31, 2014 and 2013 related to unrealized gains and losses on available-for-sale marketable securities. For the three months ended March 31, 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

3 Months Ended

Mar. 31, 2014

Fair Value Disclosures [Abstract]

Fair Value Measurements

The Company’s assets that are measured at fair value on a recurring basis, at March 31, 2014 and December 31, 2013, consist of the following:



			Fair Value Measurements at Reporting Date Using
At March 31, 2014	Fair Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)
Available-for-sale marketable securities:
U.S. government and government agency obligations	$	78,265	—		$	78,265
Corporate bonds	579,628		—		579,628
Municipal bonds	43,401		—		43,401
International government agency obligations	8,217		—		8,217
Certificates of deposit	7,918		—		7,918
Equity securities	3,535		$	3,535	—
	$	720,964	$	3,535	$	717,429

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 months ended March 31, 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 months ended March 31, 2014 and 2013. There were no transfers of marketable securities between Levels 1, 2, or 3 classifications during the three months ended March 31, 2014 and 2013.

As of March 31, 2014 and December 31, 2013, the Company had $400.0 million in aggregate principal amount of 1.875% convertible senior notes that will mature on October 1, 2016 unless earlier converted or repurchased. The fair value of the outstanding convertible senior notes was estimated to be $1,437.7 million and $1,327.2 million as of March 31, 2014 and December 31, 2013, respectively, and was determined based on Level 2 inputs, such as market and observable sources.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Inventory

3 Months Ended

Mar. 31, 2014

Inventory Disclosure [Abstract]

Inventory

Inventories

Inventories consist of the following:



	March 31,		December 31,
	2014		2013
Raw materials	$	6,792	$	9,120
Work-in-process	47,858		35,868
Finished goods	13,230		14,352
Deferred costs	18,665		11,014
	$	86,545	$	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 March 31, 2014 and 2013, cost of goods sold included inventory write-downs and reserves totaling $1.1 million and $3.2 million, respectively.

Accounts Payable and Accrued Expenses

3 Months Ended

Mar. 31, 2014

Payables and Accruals [Abstract]

Accounts Payable and Accrued Expenses

Accounts payable and accrued expenses consist of the following:



	March 31,		December 31,
	2014		2013
Accounts payable	$	32,692	$	61,936
Accrued payroll and related costs	41,754		69,429
Accrued clinical trial expense	30,828		23,654
Accrued sales-related charges, deductions, and royalties	94,554		66,855
Other accrued expenses and liabilities	38,107		29,022
	$	237,935	$	250,896

Income Taxes	3 Months Ended
Income Taxes	Mar. 31, 2014
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company is subject to U.S. federal, state, and foreign income taxes. For the three months ended March 31, 2014 and 2013, the Company recorded an income tax provision of $109.8 million and $43.0 million, respectively. The Company's effective tax rate for the three months ended March 31, 2014 and 2013 was 62.7% and 30.3%, respectively. The Company's effective tax rate for the three months ended March 31, 2014 was negatively impacted by (i) expiration at the end of 2013 of the federal tax credit for increased research activities, (ii) losses incurred in foreign jurisdictions with rates lower than the federal statutory rate, and (iii) recently enacted New York State tax legislation. 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 10.4% for the first quarter of 2014. The Company's effective tax rate for the three months ended March 31, 2013 included, as a discrete item, 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 three months ended March 31, 2013 by 12.3%. 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. In addition, the Company's 2009, 2010, and 2011 New York State returns are currently under audit by state tax authorities.

Statement of Cash Flows	3 Months Ended
Statement of Cash Flows	Mar. 31, 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 March 31, 2014 and December 31, 2013 were $17.6 million and $16.1 million, respectively, of accrued capital expenditures. Included in accounts payable and accrued expenses at March 31, 2013 and December 31, 2012 were $10.1 million and $8.6 million, respectively, of accrued capital expenditures. Pursuant to the application of FASB authoritative guidance to the Company's lease of office and laboratory facilities in Tarrytown, New York, the Company recognized a facility lease obligation of $19.4 million during the three months ended March 31, 2014 in connection with capitalizing, on the Company's books, the landlord's costs of constructing new facilities that the Company has leased. The Company did not recognize any such facility lease obligation during the three months ended March 31, 2013.

Legal Matters	3 Months Ended
Legal Matters	Mar. 31, 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.

Subsequent Events	3 Months Ended
Subsequent Events	Mar. 31, 2014
Subsequent Event [Line Items]
Subsequent Events	Subsequent Events In April 2014, the Company received notification that $61.1 million principal amount of the Company's 1.875% convertible senior notes were surrendered for conversion, and settlement is anticipated during the second quarter of 2014. In accordance with the terms of the notes, the Company elected to settle these conversion obligations through a combination of cash, in an amount up to the principal amount of the converted notes, and shares in respect of any excess thereof (based on the average of the volume-weighted-average prices of the Common Stock during the 40 trading-day cash settlement averaging period specified in the indenture governing the notes). In connection with these note conversions, the Company exercised a proportionate amount of its convertible note hedges, for which the Company expects to receive shares of Common Stock equivalent to the number of shares the Company will be required to issue to settle the non-cash portion of the related note conversions. In May 2014, the Company entered into a research collaboration and license agreement with Avalanche Biotechnologies, Inc., a privately held company, to discover, develop, and commercialize novel gene therapy products for the treatment of ophthalmologic diseases. In connection with the agreement, the Company is required to make 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, potential development and regulatory milestones (for products directed to as many as eight therapeutic targets), and royalties on any future sales of such products. The Company has 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 FDA for a product candidate, 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.

Net Product Sales (Policies)	3 Months Ended
Net Product Sales (Policies)	Mar. 31, 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)	3 Months Ended
Legal Matters (Policies)	Mar. 31, 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)

3 Months Ended

Mar. 31, 2014

Revenues [Abstract]

Sales Related Deductions Activity

The following table summarizes the provisions, and credits/payments, for these sales-related deductions during the three months ended March 31, 2014.



	Rebates & Chargebacks			Distribution- Related Fees			Other Sales- Related Deductions			Total
Balance as of December 31, 2013	$	4,400		$	19,663		$	538		$	24,601
Provision related to current period sales	6,886			16,858			448			24,192
Credits/payments	(6,664		)	(16,310		)	(454		)	(23,428		)
Balance as of March 31, 2014	$	4,622		$	20,211		$	532		$	25,365

Collaboration Agreements (Tables)

3 Months Ended

Mar. 31, 2014

Research and Development Arrangement, Contract to Perform for Others [Line Items]

Collaboration revenue with related party



	Three months ended March 31,
Sanofi Collaboration Revenue	2014			2013
ZALTRAP:
Regeneron's share of losses in connection with commercialization of ZALTRAP	$	(3,212	)	$	(7,789	)
Reimbursement of Regeneron research and development expenses	1,092			2,089
Other	2,177			1,858
Total ZALTRAP	57			(3,842		)
Antibody:
Reimbursement of Regeneron research and development expenses	126,822			99,623
Other	3,629			3,492
Total Antibody	130,451			103,115
Total Sanofi collaboration revenue	$	130,508		$	99,273

Collaboration revenue

The collaboration revenue the Company earned from Bayer HealthCare is detailed below:



	Three months ended March 31,
Bayer HealthCare Collaboration Revenue	2014		2013
EYLEA:
Regeneron's net profit in connection with commercialization of EYLEA outside the United States	$	61,159	$	6,362
Sales milestones	30,000		—
Cost-sharing of Regeneron EYLEA development expenses	20,347		5,888
Other	10,932		2,657
Total EYLEA	122,438		14,907
PDGFR-beta antibody:
Cost-sharing of REGN2176-3 development expenses	513		—
Other	2,361		—
Total PDGFR-beta	2,874		—
Total Bayer HealthCare collaboration revenue	$	125,312	$	14,907

Net Income Per Share (Tables)

3 Months Ended

Mar. 31, 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 March 31,
	2014		2013
Net income - basic and diluted	$	65,443	$	98,874

(Shares in thousands)
Weighted average shares - basic	98,709		96,878
Effect of dilutive securities:
Stock options	9,879		10,276
Restricted stock	401		325
Warrants	3,162		1,890
Dilutive potential shares	13,442		12,491
Weighted average shares - diluted	112,151		109,369

Net income per share - basic	$	0.66	$	1.02
Net income per share - diluted	$	0.58	$	0.90

Antidilutive Securities

Shares which have been excluded from the March 31, 2014 and 2013 diluted per share amounts because their effect would have been antidilutive, include the following:

Marketable Securities (Tables)

3 Months Ended

Mar. 31, 2014

Investments, Debt and Equity Securities [Abstract]

Available-for-sale Securities

The following tables summarize the Company's investments in marketable securities at March 31, 2014 and December 31, 2013.



	Amortized		Unrealized					Fair
At March 31, 2014	Cost Basis		Gains		Losses			Value
U.S. government and government agency obligations	$	78,196	$	82	$	(13	)	$	78,265
Corporate bonds	579,600		517		(489		)	579,628
Municipal bonds	43,276		138		(13		)	43,401
International government agency obligations	8,214		3		—			8,217
Certificates of deposit	7,914		4		—			7,918
Equity securities	1,166		2,369		—			3,535
Total marketable securities	$	718,366	$	3,113	$	(515	)	$	720,964

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 March 31, 2014 and December 31, 2013 consist of the following:



	March 31, 2014		December 31, 2013
Maturities within one year	$	186,275	$	158,376
Maturities after one year through five years	525,961		383,410
Maturities after five years through ten years	4,042		4,138
Maturities after ten years	1,151		1,177
	$	717,429	$	547,101

Fair Value and Unrealized Losses of Marketable Securities



	Less than 12 Months					12 Months or Greater		Total
At March 31, 2014	Fair Value		Unrealized Loss			Fair Value	Unrealized Loss	Fair Value		Unrealized Loss
U.S. government and government agency obligations	$	5,983	$	(13	)	—	—	$	5,983	$	(13	)
Corporate bonds	268,174		(489		)	—	—	268,174		(489		)
Municipal bonds	12,187		(13		)	—	—	12,187		(13		)
	$	286,344	$	(515	)	—	—	$	286,344	$	(515	)

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	)

- Definition

Tabular disclosure of available-for-sale securities which includes, but is not limited to, changes in the cost basis and fair value, fair value and gross unrealized gain (loss), fair values by type of security, contractual maturity and classification, amortized cost basis, contracts to acquire securities to be accounted for as available-for-sale, debt maturities, transfers to trading, change in net unrealized holding gain (loss) net of tax, continuous unrealized loss position fair value, aggregate losses qualitative disclosures, other than temporary impairment (OTTI) losses or other disclosures related to available for sale securities.

+ References + Details

Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 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 March 31, 2014 and December 31, 2013, consist of the following:



			Fair Value Measurements at Reporting Date Using
At March 31, 2014	Fair Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)
Available-for-sale marketable securities:
U.S. government and government agency obligations	$	78,265	—		$	78,265
Corporate bonds	579,628		—		579,628
Municipal bonds	43,401		—		43,401
International government agency obligations	8,217		—		8,217
Certificates of deposit	7,918		—		7,918
Equity securities	3,535		$	3,535	—
	$	720,964	$	3,535	$	717,429

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)

3 Months Ended

Mar. 31, 2014

Inventory Disclosure [Abstract]

Schedule of Inventory, Current

Inventories consist of the following:



	March 31,		December 31,
	2014		2013
Raw materials	$	6,792	$	9,120
Work-in-process	47,858		35,868
Finished goods	13,230		14,352
Deferred costs	18,665		11,014
	$	86,545	$	70,354

Accounts Payable and Accrued Expenses (Tables)

3 Months Ended

Mar. 31, 2014

Payables and Accruals [Abstract]

Schedule of Accounts Payable and Accrued Liabilities

Accounts payable and accrued expenses consist of the following:



	March 31,		December 31,
	2014		2013
Accounts payable	$	32,692	$	61,936
Accrued payroll and related costs	41,754		69,429
Accrued clinical trial expense	30,828		23,654
Accrued sales-related charges, deductions, and royalties	94,554		66,855
Other accrued expenses and liabilities	38,107		29,022
	$	237,935	$	250,896

Net Product Sales (Details) - USD ($) $ in Thousands	3 Months Ended
Net Product Sales (Details) - USD ($) $ in Thousands	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Revenue Disclosure [Line Items]
Net product sales	$ 362,378	$ 318,740
Activity of Sales Related Deductions [Roll Forward]
Balance	25,365		$ 24,601
Provision related to current period sales	24,192
Credits/payments	(23,428)
Rebates and Chargebacks
Activity of Sales Related Deductions [Roll Forward]
Balance	4,622		4,400
Provision related to current period sales	6,886
Credits/payments	(6,664)
Distribution Related Fees
Activity of Sales Related Deductions [Roll Forward]
Balance	20,211		19,663
Provision related to current period sales	16,858
Credits/payments	(16,310)
Other Sales Related Deductions
Activity of Sales Related Deductions [Roll Forward]
Balance	532		$ 538
Provision related to current period sales	448
Credits/payments	$ (454)
Customer concentration risk \| Gross Sales Revenue
Risks and Uncertainties [Abstract]
Concentration risk, percentage	79.00%	77.00%
EYLEA
Revenue Disclosure [Line Items]
Net product sales	$ 359,000	$ 313,900
ARCALYST
Revenue Disclosure [Line Items]
Net product sales	$ 3,400	$ 4,800

Collaboration Agreements (Details) $ in Thousands	3 Months Ended
Collaboration Agreements (Details) $ in Thousands	Mar. 31, 2014 USD ($)	Mar. 31, 2013 USD ($)
Collaboration Agreements [Line Items]
Research and Development Expense	$ 287,379	$ 180,299
Number of sales milestone payments the Company received	2
Number of Payments the Company made	2
Revenue from Related Parties	$ 130,508	99,273
Other Collaboration Revenue	125,312	14,907
Deferred Revenue, Additions	25,500
Levels of twelve month sales at which sales milestone payments were received	500,000
Levels of twelve month sales at which sales milestone payments were received - 5th tier	$ 600,000
Period for Achieving Sales Target for Milestone Payment, Rolling Basis	12 months
levels of twelve month sales at which sales milestone payments maybe received - 200 million	$ 200,000
levels of twelve months sales at which sales milestone payments maybe received - 1 billion	1,000,000
Amount of non-refundable payment received for collaboration agreement	25,500
sales achievement - 500 million
Collaboration Agreements [Line Items]
Revenue Recognition, Milestone Method, Revenue Recognized	15,000
sales achievement - 600 million
Collaboration Agreements [Line Items]
Revenue Recognition, Milestone Method, Revenue Recognized	15,000
sales achievement - 1 billion
Collaboration Agreements [Line Items]
Maximum amount of milestone payments that may be received if certain sales are achieved	60,000
sales achievement - 200 million
Collaboration Agreements [Line Items]
Maximum amount of sales milestone payments if total sales achieve specific levels	30,000
ZALTRAP Agreement
Collaboration Agreements [Line Items]
Net profit (loss) from commercialization of products under collaboration agreement	(3,212)	(7,789)
Research and Development Arrangement, Contract to Perform for Others, Compensation Earned	1,092	2,089
Contracts Revenue	2,177	1,858
Revenue from Related Parties	$ 57	(3,842)
Antibody Collaboration
Collaboration Agreements [Line Items]
Percentage of Trial Costs borne by collaborating party	80.00%
Percentage of Trial Costs borne by entity	20.00%
Research and Development Expense	$ 23,800
Other Research and Development Expense	5,000
Research and Development Arrangement, Contract to Perform for Others, Compensation Earned	126,822	99,623
Contracts Revenue	3,629	3,492
Revenue from Related Parties	130,451	103,115
Milestone Payment	30,000
Collaboration Agreement with Bayer HealthCare
Collaboration Agreements [Line Items]
Opt-in payment	20,000
Amount of milestone payment that may be received relating to marketing approval	20,000
Revenue Recognition, Milestone Method, Revenue Recognized	2,500
Future development milestone payments	15,000
Deferred Revenue, Additions	$ 2,500
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
EYLEA
Collaboration Agreements [Line Items]
Net profit (loss) from commercialization of products under collaboration agreement	$ 61,159	6,362
Revenue Recognition, Milestone Method, Revenue Recognized	30,000	0
Research and Development Arrangement, Contract to Perform for Others, Compensation Earned	20,347	5,888
Contracts Revenue	10,932	2,657
Other Collaboration Revenue	122,438	14,907
PDGFR-beta
Collaboration Agreements [Line Items]
Research and Development Arrangement, Contract to Perform for Others, Compensation Earned	513	0
Contracts Revenue	2,361	0
Other Collaboration Revenue	2,874	$ 0
BRVO
Collaboration Agreements [Line Items]
Research and Development Arrangement, Contract to Perform for Others, Compensation Earned	$ 15,700

Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Earnings Per Share [Abstract]
Net income	$ 65,443	$ 98,874
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Weighted average shares outstanding - basic	98,709	96,878
Effect of dilutive securities (in shares):
Stock options	9,879	10,276
Restricted stock	401	325
Warrants	3,162	1,890
Dilutive potential shares	13,442	12,491
Weighted average shares - diluted (in shares)	112,151	109,369
Earnings Per Share, Basic and Diluted [Abstract]
Net income per share - basic	$ 0.66	$ 1.02
Net income per share - diluted (in dollars per share)	$ 0.58	$ 0.90
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average number of shares	3,646	3,868
Convertible senior notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average number of shares	4,761	4,761

Marketable Securities (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Marketable Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost Basis	$ 718,366	$ 548,322
Unrealized Gains	3,113	392
Unrealized (Losses)	(515)	(447)
Total fair value of available-for-sale marketable securities	720,964	548,267
Available-for-sale Securities, Debt Maturities, Fair Value [Abstract]
Maturities within one year	186,275	158,376
Maturities after one year through five years	525,961	383,410
Maturities after five years through ten years	4,042	4,138
Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value	1,151	1,177
Total	717,429	547,101
Continuous Unrealized Loss Position, Fair Value [Abstract]
Fair Value - Less than 12 Months	286,344	239,812
Fair Value - 12 Months or Greater	0	0
Fair Value - Total	286,344	239,812
Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Unrealized Loss - Less than 12 months	(515)	(447)
Unrealized Loss - 12 Months or Greater	0	0
Unrealized Loss - Total	(515)	(447)
U.S. government and government agency obligations
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost Basis	78,196	107,493
Unrealized Gains	82	55
Unrealized (Losses)	(13)	(27)
Total fair value of available-for-sale marketable securities	78,265	107,521
Continuous Unrealized Loss Position, Fair Value [Abstract]
Fair Value - Less than 12 Months	5,983	49,241
Fair Value - Total	5,983	49,241
Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Unrealized Loss - Less than 12 months	(13)	(27)
Unrealized Loss - Total	(13)	(27)
Corporate bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost Basis	579,600	369,321
Unrealized Gains	517	233
Unrealized (Losses)	(489)	(361)
Total fair value of available-for-sale marketable securities	579,628	369,193
Continuous Unrealized Loss Position, Fair Value [Abstract]
Fair Value - Less than 12 Months	268,174	176,140
Fair Value - Total	268,174	176,140
Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Unrealized Loss - Less than 12 months	(489)	(361)
Unrealized Loss - Total	(489)	(361)
Commercial Paper
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost Basis		23,891
Unrealized Gains		53
Unrealized (Losses)		0
Total fair value of available-for-sale marketable securities		23,944
Municipal bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost Basis	43,276	36,935
Unrealized Gains	138	45
Unrealized (Losses)	(13)	(59)
Total fair value of available-for-sale marketable securities	43,401	36,921
Continuous Unrealized Loss Position, Fair Value [Abstract]
Fair Value - Less than 12 Months	12,187	14,431
Fair Value - Total	12,187	14,431
Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Unrealized Loss - Less than 12 months	(13)	(59)
Unrealized Loss - Total	(13)	(59)
International government agency obligations
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost Basis	8,214	2,007
Unrealized Gains	3	1
Unrealized (Losses)	0	0
Total fair value of available-for-sale marketable securities	8,217	2,008
Certificates of Deposit
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost Basis	7,914	7,509
Unrealized Gains	4	5
Unrealized (Losses)	0	0
Total fair value of available-for-sale marketable securities	7,918	7,514
Equity Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost Basis	1,166	1,166
Unrealized Gains	2,369	0
Unrealized (Losses)	0	0
Total fair value of available-for-sale marketable securities	$ 3,535	$ 1,166

Fair Value Measurements (Details) - USD ($)	3 Months Ended
Fair Value Measurements (Details) - USD ($)	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Available-for-sale marketable securities:
Total fair value of available-for-sale marketable securities	$ 720,964,000		$ 548,267,000
Convertible senior notes
Convertible Debt [Abstract]
Total convertible senior notes - par	$ 400,000,000		$ 400,000,000
Interest rate, stated percentage	1.875%		1.875%
Fair value of the outstanding notes	$ 1,437,700,000		$ 1,327,200,000
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
Measured on a recurring basis \| Fair Value
Available-for-sale marketable securities:
U.S. government and government agency obligations	78,265,000		107,521,000
Corporate bonds	579,628,000		369,193,000
Commercial paper			23,944,000
Municipal bonds	43,401,000		36,921,000
International government agency obligations	8,217,000		2,008,000
Certificates of deposit	7,918,000		7,514,000
Equity securities	3,535,000		1,166,000
Total fair value of available-for-sale marketable securities	720,964,000		548,267,000
Measured on a recurring basis \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Available-for-sale marketable securities:
Equity securities	3,535,000		1,166,000
Total fair value of available-for-sale marketable securities	3,535,000		1,166,000
Measured on a recurring basis \| Significant Other Observable Inputs (Level 2)
Available-for-sale marketable securities:
U.S. government and government agency obligations	78,265,000		107,521,000
Corporate bonds	579,628,000		369,193,000
Commercial paper			23,944,000
Municipal bonds	43,401,000		36,921,000
International government agency obligations	8,217,000		2,008,000
Certificates of deposit	7,918,000		7,514,000
Total fair value of available-for-sale marketable securities	$ 717,429,000		$ 547,101,000

Inventory (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Inventory (Details) - USD ($) $ in Thousands	Mar. 31, 2014	Dec. 31, 2013
Inventory Disclosure [Abstract]
Raw materials	$ 6,792	$ 9,120
Work in process	47,858	35,868
Finished goods	13,230	14,352
Deferred costs	18,665	11,014
Total Inventories	86,545	70,354
Inventory write-downs and reserves	$ 1,100	$ 3,200

Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2014	Dec. 31, 2013
Accounts Payable and Accrued Liabilities, Current [Abstract]
Accounts payable	$ 32,692	$ 61,936
Accrued payroll and related costs	41,754	69,429
Accrued clinical trial expense	30,828	23,654
Accrued sales-related deductions and royalties	94,554	66,855
Other accrued expenses and liabilities	38,107	29,022
Accounts payable and accrued expenses	$ 237,935	$ 250,896

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
Income Taxes (Details) - USD ($) $ in Thousands	Mar. 31, 2014	Mar. 31, 2013
Deferred:
Total deferred tax expense (benefit)	$ (8,522)	$ 39,525
Total income tax expense (benefit)	$ 109,820	$ 42,957
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Effective income tax rate	62.70%	30.30%
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent	0.00%
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Percent	10.40%
Operating Loss Carryforwards [Line Items]
Effective Income Tax Rate Reconciliation, Tax Credit, Research, Percent		12.30%

Statement of Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended
Statement of Cash Flows (Details) - USD ($) $ in Millions	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013	Dec. 31, 2012
Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract]
Accrued capital expenditures	$ 17.6	$ 10.1	$ 16.1	$ 8.6
Facility lease obligation recognized during the period	$ 19.4	$ 0.0

Subsequent Events (Details) $ in Millions	1 Months Ended	3 Months Ended
Subsequent Events (Details) $ in Millions	May 31, 2014 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2013
Collaboration Agreement with Avalanche Biotechnologies, inc. [Member]
Subsequent Event [Line Items]
Research and Development Expense	$ 6.0
Research and Development Asset Acquired Other than Through Business Combination, Written-off	$ 2.0
Number of therapeutic targets	8
Payment to acquire preferred share of non-public entity	$ 5.0
Number of therapeutic targets of Avalanche's choice	2
Convertible Debt [Member]
Subsequent Event [Line Items]
Debt Conversion, Converted Instrument, Amount		$ 61.1
Debt Instrument, Interest Rate, Stated Percentage		1.875%	1.875%
Trading Days for cash settlement		40