BioMarin Pharmaceutical (BMRN) 10-Q 3 Nov 16 2016 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2016	Oct. 28, 2016
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q3
Trading Symbol	BMRN
Entity Registrant Name	BIOMARIN PHARMACEUTICAL INC
Entity Central Index Key	1,048,477
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		171,987,437

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	[1]
Current assets:
Cash and cash equivalents	$ 707,349	$ 397,040
Short-term investments	327,499	195,579
Accounts receivable, net (allowance for doubtful accounts: $66 and $93, at September 30, 2016 and December 31, 2015, respectively)	215,894	164,959
Inventory	347,420	271,683
Other current assets	68,409	60,378
Total current assets	1,666,571	1,089,639
Noncurrent assets:
Long-term investments	362,956	425,652
Property, plant and equipment, net	729,836	704,207
Intangible assets, net	561,387	683,996
Goodwill	197,039	197,039
Deferred tax assets	288,006	220,191
Other assets	36,443	408,644
Total assets	3,842,238	3,729,368
Current liabilities:
Accounts payable and accrued liabilities	306,129	392,511
Short-term convertible debt, net	22,460	0
Short-term contingent acquisition consideration payable	48,746	52,946
Total current liabilities	377,335	445,457
Noncurrent liabilities:
Long-term convertible debt, net	653,178	662,286
Long-term contingent acquisition consideration payable	122,644	32,663
Deferred tax liabilities	0	143,527
Other long-term liabilities	43,273	44,588
Total liabilities	1,196,430	1,328,521
Stockholders’ equity:
Common stock, $0.001 par value: 250,000,000 shares authorized at September 30, 2016 and December 31, 2015: 171,697,649 and 161,526,044 shares issued and outstanding at September 30, 2016 and December 31, 2015, respectively	173	162
Additional paid-in capital	4,231,514	3,414,837
Company common stock held by Nonqualified Deferred Compensation Plan (the NQDC)	(14,969)	(13,616)
Accumulated other comprehensive income	2,158	21,033
Accumulated deficit	(1,573,068)	(1,021,569)
Total stockholders’ equity	2,645,808	2,400,847
Total liabilities and stockholders’ equity	$ 3,842,238	$ 3,729,368
[1]	December 31, 2015 balances were derived from the audited Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015, filed with the Securities and Exchange Commission (the SEC) on February 29, 2016.

CONDENSED CONSOLIDATED BALANCE3

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	[1]
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts	$ 66	$ 93
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	171,697,649	161,526,044
Common stock, shares outstanding	171,697,649	161,526,044
[1]	December 31, 2015 balances were derived from the audited Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015, filed with the Securities and Exchange Commission (the SEC) on February 29, 2016.

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
REVENUES:
Net product revenues	$ 278,262	$ 207,767	$ 812,195	$ 658,102
Collaborative agreement revenues	1	131	234	849
Royalty, license and other revenues	1,633	1,006	4,334	3,008
Total revenues	279,896	208,904	816,763	661,959
OPERATING EXPENSES:
Cost of sales	50,738	34,904	145,473	103,965
Research and development	160,831	158,713	486,663	458,688
Selling, general and administrative	118,758	94,044	333,635	288,364
Intangible asset amortization and contingent consideration	9,654	3,116	(34,318)	22,963
Impairment of intangible assets	0	0	599,118	0
Total operating expenses	339,981	290,777	1,530,571	873,980
LOSS FROM OPERATIONS	(60,085)	(81,873)	(713,808)	(212,021)
Equity in the loss of BioMarin/Genzyme LLC	(104)	(186)	(374)	(539)
Interest income	1,633	1,344	4,561	3,050
Interest expense	(9,980)	(9,447)	(29,767)	(28,911)
Debt conversion expense	0	0	0	(163)
Other income (expense)	1,723	(281)	504	(9,105)
LOSS BEFORE INCOME TAXES	(66,813)	(90,443)	(738,884)	(247,689)
Provision for (benefit from) income taxes	(24,016)	483	(187,385)	(7,273)
NET LOSS	$ (42,797)	$ (90,926)	$ (551,499)	$ (240,416)
NET LOSS PER SHARE, BASIC	$ (0.26)	$ (0.57)	$ (3.36)	$ (1.51)
NET LOSS PER SHARE, DILUTED	$ (0.26)	$ (0.60)	$ (3.37)	$ (1.51)
Weighted average common shares outstanding, basic	167,714	160,886	163,963	159,647
Weighted average common shares outstanding, diluted	167,714	161,134	164,216	159,647
COMPREHENSIVE LOSS	$ (45,167)	$ (98,203)	$ (570,374)	$ (242,698)

CONDENSED CONSOLIDATED STATEME5

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total		Common Stock	Additional Paid-in Capital	Company Common Stock Held By The NQDC	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning Balance at Dec. 31, 2014						$ 27,466
Net loss	$ (240,416)
Ending Balance at Sep. 30, 2015						25,184
Beginning Balance at Jun. 30, 2015						32,461
Net loss	(90,926)
Ending Balance at Sep. 30, 2015						25,184
Beginning Balance at Dec. 31, 2015	2,400,847	[1]	$ 162	$ 3,414,837	$ (13,616)	21,033	$ (1,021,569)
Beginning Balance (in shares) at Dec. 31, 2015			161,526
Net loss	(551,499)						(551,499)
Other comprehensive loss	(18,875)					(18,875)
Issuance of common stock, net of offering costs	712,938		$ 8	712,930
Issuance of common stock, net of offering costs (in shares)			7,500
Issuance of common stock under the 2006 Employee Stock Purchase Plan (the ESPP)	6,048			6,048
Issuance of common stock under the 2006 Employee Stock Purchase Plan (the ESPP) (in shares)			110
Exercise of common stock options	43,450		$ 1	43,449
Exercise of common stock options (in shares)			1,345
Excess tax benefit from stock option exercises	563			563
Restricted stock units vested during the period, net (in shares)			779
Restricted stock units vested during the period, net	(55,241)		$ 1	(55,242)
Conversion of convertible notes, net (in shares)			438
Conversion of convertible notes, net	8,924		$ 1	8,923
Common stock held by the NQDC	(1,353)				(1,353)
Stock-based compensation	100,006			100,006
Ending Balance at Sep. 30, 2016	2,645,808		$ 173	4,231,514	(14,969)	2,158	(1,573,068)
Ending Balance (in shares) at Sep. 30, 2016			171,698
Beginning Balance at Jun. 30, 2016						4,528
Net loss	(42,797)
Ending Balance at Sep. 30, 2016	$ 2,645,808		$ 173	$ 4,231,514	$ (14,969)	$ 2,158	$ (1,573,068)
Ending Balance (in shares) at Sep. 30, 2016			171,698
[1]	December 31, 2015 balances were derived from the audited Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015, filed with the Securities and Exchange Commission (the SEC) on February 29, 2016.

CONDENSED CONSOLIDATED STATEME6

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016		Sep. 30, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (551,499)		$ (240,416)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	76,805		34,301
Non-cash interest expense	22,276		21,243
Accretion of discount on investments	681		1,616
Stock-based compensation	97,220		80,959
(Gain) loss on sale of equity investment	2,020		(3,022)
Impairment of assets	599,118		12,802
Deferred income taxes	(206,691)		14,629
Excess tax benefit from stock option exercises	(563)		(463)
Unrealized foreign exchange gain on forward contracts	(10,961)		(16,491)
Non-cash changes in the fair value of contingent acquisition consideration payable	(56,954)		15,101
Other	1,044		1,059
Changes in operating assets and liabilities:
Accounts receivable, net	(52,023)		146
Inventory	(59,802)		(47,469)
Other current assets	(1,556)		(27,970)
Other assets	(5,002)		(1,391)
Accounts payable and accrued liabilities	(77,852)		924
Other long-term liabilities	(4,451)		790
Net cash used in operating activities	(228,190)		(153,652)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property, plant and equipment	(96,806)		(123,844)
Funds held in escrow for the purchase of real property	(8,383)		(12,500)
Maturities and sales of investments	302,801		261,786
Purchase of available-for-sale securities	(370,393)		(842,873)
Purchase of promissory note	0		(3,326)
Business acquisitions, net of cash acquired	(1,467)		(538,392)
Other	(150)		0
Net cash used in investing activities	(174,398)		(1,259,149)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from exercises of stock options and the ESPP	49,498		51,515
Taxes paid related to net share settlement of equity awards	(55,241)		(21,968)
Proceeds from public offering of common stock, net	712,938		888,257
Excess tax benefit from stock option exercises	563		463
Other	0		(2,062)
Net cash provided by financing activities	707,758		916,205
Effect of exchange rate changes on cash	5,139		(2,544)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	310,309		(499,140)
Cash and cash equivalents:
Beginning of period	397,040	[1]	875,486
End of period	707,349		376,346
SUPPLEMENTAL CASH FLOW DISCLOSURES:
Cash paid for interest, net of interest capitalized into fixed assets	4,564		4,979
Cash paid for income taxes	95,163		15,377
Stock-based compensation capitalized into inventory	8,960		8,271
Depreciation capitalized into inventory	13,402		11,005
SUPPLEMENTAL CASH FLOW DISCLOSURES FOR NON CASH INVESTING AND FINANCING ACTIVITIES:
Decrease in accounts payable and accrued liabilities related to fixed assets	(13,988)		(11,386)
Conversion of convertible debt	8,924		8,957
Accrual for inventory purchases related to the acquisition of the Merck PKU Business	$ 1,322		$ 0
[1]	December 31, 2015 balances were derived from the audited Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015, filed with the Securities and Exchange Commission (the SEC) on February 29, 2016.

NATURE OF OPERATIONS AND BUSINE

NATURE OF OPERATIONS AND BUSINESS RISKS	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
NATURE OF OPERATIONS AND BUSINESS RISKS	(1) NATURE OF OPERATIONS AND BUSINESS RISKS BioMarin Pharmaceutical Inc. (the Company), a Delaware corporation, develops and commercializes innovative biopharmaceuticals for serious diseases and medical conditions. The Company selects product candidates for diseases and conditions that represent a significant unmet medical need, have well-understood biology and provide an opportunity to be first-to-market or offer a significant benefit over existing products. The Company’s product portfolio consists of five approved products and multiple clinical and investigational product candidates. The Company’s approved products are Vimizim (elosulfase alfa), Naglazyme (galsulfase), Kuvan (sapropterin dihydrochloride), Aldurazyme (laronidase) and Firdapse (amifampridine phosphate). The Company expects to continue to finance future cash needs that exceed its operating activities primarily through its current cash, cash equivalents, short-term and long-term investments and, to the extent appropriate, through proceeds from equity or debt financings, loans and collaborative agreements with corporate partners. Until the Company consistently generates positive cash flows from its operations, the Company expects to raise the capital necessary to fund its current operations and long-term plans. Additional capital may also be necessary if the Company enters into potential licenses and other acquisitions of complementary technologies, products or companies. The Company is subject to a number of risks and uncertainties, including, without limitation: the financial performance of its approved products; the expected need for additional financings; the Company’s ability to successfully commercialize its approved products; the uncertainty of the Company’s research and development (R&D) efforts resulting in future successful commercial products; the Company’s ability to successfully obtain regulatory approval for new products; the Company’s ability to compete effectively; reliance on the proprietary technology of others; dependence on key personnel; uncertain patent protection; dependence on corporate partners and collaborators; and possible restrictions on reimbursement from governmental agencies and healthcare organizations, as well as other changes in the health care industry.

BASIS OF PRESENTATION

BASIS OF PRESENTATION	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
BASIS OF PRESENTATION	(2) BASIS OF PRESENTATION The accompanying Condensed Consolidated Financial Statements have been prepared pursuant to the rules and regulations of the SEC for Quarterly Reports on Form 10-Q and do not include all of the information and note disclosures required by the United States generally accepted accounting principles (U.S. GAAP) for complete financial statements, although the Company believes that the disclosures herein are adequate to ensure that the information presented is not misleading. The Condensed Consolidated Financial Statements should therefore be read in conjunction with the Consolidated Financial Statements and Notes thereto for the fiscal year ended December 31, 2015 included in the Company’s Annual Report on Form 10-K. The accompanying Condensed Consolidated Financial Statements have been prepared in accordance with U.S. GAAP, which requires management to make estimates and assumptions that affect amounts reported in the Condensed Consolidated Financial Statements and accompanying disclosures. Although these estimates are based on management’s best knowledge of current events and actions that the Company may undertake in the future, actual results may be different from those estimates. The Condensed Consolidated Financial Statements reflect all adjustments of a normal, recurring nature that are, in the opinion of management, necessary for a fair presentation of results for these interim periods. The results of operations for the three and nine months ended September 30, 2016 are not necessarily indicative of the results that may be expected for the fiscal year ending December 31, 2016 or any other period. Management performed an evaluation of the Company’s activities through the date of filing of this Quarterly Report on Form 10-Q, and has concluded that there were no subsequent events or transactions that occurred subsequent to the balance sheet date prior to filing this Quarterly Report on Form 10-Q that would require recognition or disclosure in the Condensed Consolidated Financial Statements.

SIGNIFICANT ACCOUNTING POLICIES

SIGNIFICANT ACCOUNTING POLICIES	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
SIGNIFICANT ACCOUNTING POLICIES	(3) SIGNIFICANT ACCOUNTING POLICIES There have been no material changes to the Company’s significant accounting policies during the nine months ended September 30, 2016, as compared to the significant accounting policies disclosed in Note 3 of the Consolidated Financial Statements in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015.

RECENT ACCOUNTING PRONOUNCEMENT

RECENT ACCOUNTING PRONOUNCEMENTS	9 Months Ended
	Sep. 30, 2016
Accounting Changes And Error Corrections [Abstract]
RECENT ACCOUNTING PRONOUNCEMENTS	(4) RECENT ACCOUNTING PRONOUNCEMENTS Except as described below, there have been no new accounting pronouncements or changes to accounting pronouncements during the nine months ended September 30, 2016, as compared to the recent accounting pronouncements described in Note 4 of the Company’s Annual Report on Form 10-K for the year ended December 31, 2015, that are of significance or potential significance to the Company. In March 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2016-09, Improvements to Employee Share-Based Payment Accounting (ASU 2016-09), which is intended to simplify several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. ASU 2016-09 will be effective for the Company’s fiscal year beginning January 1, 2017 unless it elects early adoption. In February 2016, the FASB issued ASU No. 2016-02, Leases (ASU 2016-02). The amended guidance requires balance sheet recognition of lease assets and liabilities by lessees for leases classified as operating leases, with an option to not recognize lease assets and lease liabilities for leases with a term of 12 months or less. The amendments also require new disclosures providing additional qualitative and quantitative information about the amounts recorded in the financial statements. Lessor accounting is largely unchanged. ASU 2016-02 will be effective for the Company’s fiscal year beginning January 1, 2019 unless it elects early adoption. The amendments require a modified retrospective approach with optional practical expedients. In May 2014, the FASB issued ASU No. 2014-09 (ASU 2014-09) regarding Accounting Standards Codification (ASC) Topic 606, Revenue from Contracts with Customers .

ACQUISITIONS

ACQUISITIONS	9 Months Ended
	Sep. 30, 2016
Business Combinations [Abstract]
ACQUISITIONS	(5) ACQUISITIONS The Merck PKU Business On October 1, 2015, the Company entered into a Termination and Transition Agreement with Ares Trading S.A. (Merck Serono), as amended and restated on December 23, 2015 (the A&R Kuvan Agreement), to terminate the Development, License and Commercialization Agreement, dated May 13, 2005, as amended (the License Agreement), between the Company and Merck Serono, including the license to Kuvan the Company had granted to Merck Serono under the License Agreement. Also on October 1, 2015, the Company and Merck Serono entered into a Termination Agreement (the Pegvaliase Agreement) to terminate the license to pegvaliase the Company had granted to Merck Serono under the License Agreement. On January 1, 2016, pursuant to the A&R Kuvan Agreement and the Pegvaliase Agreement, the Company completed the acquisition from Merck Serono and its affiliates of certain rights and other assets with respect to Kuvan and pegvaliase (the Merck PKU Business). As a result, the Company acquired all global rights to Kuvan and pegvaliase from Merck Serono, with the exception of Kuvan in Japan. Previously, the Company had exclusive rights to Kuvan in the United States (U.S.) and Canada and pegvaliase in the U.S. and Japan. In connection with the acquisition of the , the Company recognized transaction costs of $0.6 million, of which $0.3 million was recognized in each of the year ended December 31, 2015 and in the nine month period ended . Pursuant to the A&R Kuvan Agreement, the Company paid Merck Serono $374.5 million € € The Company and Merck Serono have no further rights or obligations under the License Agreement with respect to pegvaliase. The License Agreement will continue in effect, but in no event later than December 31, 2016, in order to complete the transfer of certain assets related to Kuvan, the majority of which occurred in January 2016. Accordingly, as of September 30, 2016, the Company continues to rely on Merck Serono to provide critical transition services for the sales and distribution of Kuvan in approximately eight remaining countries until marketing authorizations can be transferred in such countries. Prior to the consummation of the transactions described above, the Company sold Kuvan to Merck Serono at a price near its manufacturing costs, and Merck Serono resold the product to end users outside the U.S., Canada and Japan. The royalty earned by the Company from Kuvan product sold by Merck Serono was included as a component of Net Product Revenues in the period earned. Kuvan is a commercialized product for the treatment of patients with phenylketonuria (PKU) and/or for primary BH4 deficiency in certain countries. Pegvaliase is currently in pivotal studies as a potential therapeutic option for adult patients with PKU. In March 2016, the Company announced that its pivotal Phase 3 PRISM-2 study of pegvaliase met the primary endpoint of change in blood Phe compared with placebo (p<0.0001); and the Company also announced its plans to submit a marketing application in the U.S. Kuvan has Orphan Drug exclusivity in the European Union (EU) until 2020, and pegvaliase has Orphan Drug designation in the U.S. and the EU. The acquisition date fair value of the contingent acquisition consideration payments, Kuvan global marketing rights, with the exception of Japan, and pegvaliase in-process research and development (IPR&D) acquired was estimated by applying a probability-based income approach utilizing an appropriate discount rate. This estimation was based on significant inputs that are not observable in the market, referred to as level 3 inputs. The range of outcomes and assumptions used to develop these estimates has been updated to estimate the fair value of the contingent acquisition consideration payable at September 30, 2016. The following table presents the preliminary allocation of the purchase consideration for the Merck PKU Business Cash payments $ 374,545 Estimated fair value of contingent acquisition consideration payable 138,974 Total consideration $ 513,519 Kuvan intangible assets $ 172,961 Pegvaliase IPR&D 326,359 Inventory 14,199 Total identifiable assets acquired $ 513,519 The amount allocated to the Kuvan intangible assets is considered to be finite-lived and will be amortized on a straight-line basis over its estimated useful life through 2024. The amount allocated to acquired pegvaliase IPR&D is considered to be indefinite-lived until the completion or abandonment of the associated research and development efforts. During the period the assets are considered indefinite-lived, they will not be amortized but will be tested for impairment on an annual basis and between annual tests if the Company becomes aware of any events occurring or changes in circumstances that would indicate the reduction in the fair value of the IPR&D assets below their respective carrying amounts. When development is complete, which generally occurs if and when regulatory approval to market a product is obtained, the associated assets would be deemed finite-lived and would then be amortized based on their respective estimated useful lives at that point. See Note 8 to these Condensed Consolidated Financial Statements for further discussion of the indefinite-lived intangible assets. Pro Forma Financial Information The following unaudited pro forma financial information presents the combined results of operations of the Company and the Merck PKU Business as if the acquisition occurred on January 1, 2015. This unaudited pro forma financial information is presented for informational purposes only and is not necessarily indicative of the results of future operations that would have been achieved had the acquisitions taken place at the beginning of 2015. Three Months Ended September 30, Nine Months Ended September 30, 2015 2015 Total revenues $ 225,697 $ 713,930 Net loss $ (84,395 ) $ (220,465 ) Net loss per share, basic $ (0.52 ) $ (1.38 ) Net loss per share, diluted $ (0.55 ) $ (1.38 ) Weighted average common shares outstanding, basic 160,886 159,647 Weighted average common shares outstanding, diluted 161,134 159,647

NET LOSS PER COMMON SHARE

NET LOSS PER COMMON SHARE	9 Months Ended
	Sep. 30, 2016
Earnings Per Share [Abstract]
NET LOSS PER COMMON SHARE	(6) NET LOSS PER COMMON SHARE Potentially issuable shares of common stock include shares issuable upon the exercise of outstanding employee stock option awards, common stock issuable under the Company’s ESPP, unvested restricted stock units (RSUs), common stock held by the NQDC and contingent issuances of common stock related to convertible debt. The following table sets forth the computation of basic and diluted earnings per common share (in thousands of common shares): Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 Numerator: Net loss, basic $ (42,797 ) $ (90,926 ) $ (551,499 ) $ (240,416 ) Gain on common stock held by the NQDC — (4,980 ) (1,753 ) — Net loss, diluted $ (42,797 ) $ (95,906 ) $ (553,252 ) $ (240,416 ) Denominator: Weighted-average common shares outstanding, basic 167,714 160,886 163,963 159,647 Effect of dilutive securities: Common shares held by the NQDC — 248 253 — Weighted-average common shares outstanding, diluted 167,714 161,134 164,216 159,647 Net loss per common share, basic $ (0.26 ) $ (0.57 ) $ (3.36 ) $ (1.51 ) Net loss per common share, diluted $ (0.26 ) $ (0.60 ) $ (3.37 ) $ (1.51 ) In addition to the equity instruments included in the table above, the table below presents the shares of common stock that were excluded from the computation as they were anti-dilutive using the treasury stock method (in thousands of shares): Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 Options to purchase common stock 9,610 10,503 9,610 10,503 Common stock issuable under the 2017 Notes 1,105 1,553 1,105 1,553 Common stock issuable under the 2018 and 2020 Notes 7,966 7,966 7,966 7,966 Unvested restricted stock units 2,728 1,757 2,728 1,633 Common stock potentially issuable for ESPP purchases 130 229 114 220 Common stock held by the NQDC 253 — — 248 Total number of potentially issuable shares 21,792 22,008 21,523 22,123 The effect of the Company’s 0.7% senior subordinated convertible notes due in 2018 (the 2018 Notes) and the Company’s 1.50% senior subordinated convertible notes due in 2020 (the 2020 Notes, and together with the 2018 Notes, the Notes) were excluded from the diluted net loss per common share because they were antidilutive. The Company’s closing stock price on September 30, 2016 and 2015 did not exceed the conversion price of $94.15 per share for the Notes.

INVESTMENTS

INVESTMENTS	9 Months Ended
	Sep. 30, 2016
Investments Schedule [Abstract]
INVESTMENTS	(7) INVESTMENTS All investments were classified as available-for-sale at September 30, 2016 and December 31, 2015. The amortized cost, gross unrealized holding gains or losses, and fair value of the Company’s available-for-sale securities by major security type at September 30, 2016 and December 31, 2015 are summarized in the tables below: Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Aggregate Fair Value at September 30, 2016 Certificates of deposit $ 2,800 $ — $ — $ 2,800 Corporate debt securities 420,259 873 (165 ) 420,967 Commercial paper 16,692 — — 16,692 U.S. government agency securities 249,674 190 (2 ) 249,862 Greek government-issued bonds 52 82 — 134 Total $ 689,477 $ 1,145 $ (167 ) $ 690,455 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Aggregate Fair Value at December 31, 2015 Certificates of deposit $ 63,919 $ 1 $ — $ 63,920 Corporate debt securities 358,625 20 (732 ) 357,913 Commercial paper 12,733 — — 12,733 U.S. government agency securities 186,882 — (344 ) 186,538 Greek government-issued bonds 48 79 — 127 Total $ 622,207 $ 100 $ (1,076 ) $ 621,231 As of December 31, 2015, the Company had two investments in marketable equity securities measured using quoted prices in their respective active markets that are collectively considered strategic investments. In the second quarter of 2016, the remaining shares of one strategic investment were sold for a realized loss of $2.0 million. As of September 30, 2016, the fair value of the Company’s marketable equity securities was $7.3 million, which included an unrealized gain of $4.3 million. As of December 31, 2015, the fair value of the Company’s marketable equity securities was $18.1 million, which included an unrealized gain of $12.7 million. The Company’s investments are recorded in Other Assets in the Company’s Condensed Consolidated Balance Sheets. The fair values of available-for-sale securities by contractual maturity were as follows: September 30, December 31, 2016 2015 Maturing in one year or less $ 327,499 $ 195,579 Maturing after one year through five years 362,956 425,652 Total $ 690,455 $ 621,231 Impairment assessments are made at the individual security level each reporting period. When the fair value of an investment is less than its cost at the balance sheet date, a determination is made as to whether the impairment is other-than-temporary and, if it is other-than-temporary, an impairment loss is recognized in earnings equal to the difference between the investment’s amortized cost and fair value at such date. As of September 30, 2016, some of the Company’s investments were in an unrealized loss position. However, the Company has the ability and intent to hold all investments that have been in a continuous loss position until maturity or recovery, thus no other-than-temporary impairment is deemed to have occurred. See Note 13 to these Condensed Consolidated Financial Statements for additional discussion regarding the fair value of the Company’s available-for-sale securities.

INTANGIBLE ASSETS

INTANGIBLE ASSETS	9 Months Ended
	Sep. 30, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
INTANGIBLE ASSETS	(8) INTANGIBLE ASSETS Intangible assets consisted of the following: September 30, December 31, 2016 2015 Intangible assets: Finite-lived intangible assets $ 305,122 $ 129,572 Indefinite-lived intangible assets 332,199 607,548 Gross intangible assets: 637,321 737,120 Less: Accumulated amortization (75,934 ) (53,124 ) Net carrying value $ 561,387 $ 683,996 Indefinite-Lived Intangible Assets Intangible assets related to IPR&D assets are considered to be indefinite-lived until the completion or abandonment of the associated R&D efforts. During the period the assets are considered indefinite-lived, they will not be amortized but will be tested for impairment on an annual basis and between annual tests if the Company becomes aware of any events occurring or changes in circumstances that would indicate a reduction in the fair value of the IPR&D assets below their respective carrying amounts. If and when development is complete, which generally occurs if and when regulatory approval to market a product is obtained, the associated assets would be deemed finite-lived and would then be amortized based on their respective estimated useful lives at that point in time. During the second quarter of 2016, the Company withdrew its Marketing Authorization Application (MAA) for Kyndrisa from the European Medicines Agency (EMA) and announced it would discontinue clinical and regulatory development of Kyndrisa as well as the three other first-generation follow-on products, BMN 044, BMN 045 and BMN 053 (other exons), for the treatment of distinct forms of Duchenne muscular dystrophy. Based on the then current status of the European development efforts, the Company recognized an impairment charge of $574.1 million in the second quarter of 2016 related to the Kyndrisa and other exon See Note 8 to the Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015 for additional information related to the Company’s intangible assets.

PROPERTY, PLANT AND EQUIPMENT

PROPERTY, PLANT AND EQUIPMENT	9 Months Ended
	Sep. 30, 2016
Property Plant And Equipment [Abstract]
PROPERTY, PLANT AND EQUIPMENT	(9) PROPERTY, PLANT AND EQUIPMENT Property, plant and equipment, net consisted of the following: September 30, December 31, 2016 2015 Building and improvements $ 505,894 $ 442,100 Manufacturing and laboratory equipment 229,818 145,313 Computer hardware and software 123,557 113,442 Leasehold improvements 44,802 44,247 Furniture and equipment 26,359 22,817 Land improvements 4,881 4,881 Land 45,727 45,727 Construction-in-progress 76,992 164,283 1,058,030 982,810 Less: Accumulated depreciation (328,194 ) (278,603 ) Total property, plant and equipment, net $ 729,836 $ 704,207 Construction in-process primarily includes costs related to the Company’s significant in-process projects at its facilities in Marin County, California, and its manufacturing facility in Shanbally, Cork, Ireland. Depreciation expense for the three and nine months ended September 30, 2016 was $23.2 million and $56.1 million, respectively, of which $4.4 million and $13.4 million, respectively, was capitalized into inventory. Depreciation expense for the three and nine months ended September 30, 2015 was $12.7 million and $36.4 million, respectively, of which $3.7 million and $11.0 million, respectively, was capitalized into inventory. Capitalized interest related to the Company’s property, plant and equipment purchases for each of the three and nine months ended September 30, 2016 and 2015 was insignificant.

SUPPLEMENTAL BALANCE SHEET INFO

SUPPLEMENTAL BALANCE SHEET INFORMATION	9 Months Ended
	Sep. 30, 2016
Organization Consolidation And Presentation Of Financial Statements [Abstract]
SUPPLEMENTAL BALANCE SHEET INFORMATION	(10) SUPPLEMENTAL BALANCE SHEET INFORMATION Inventory consisted of the following: September 30, December 31, 2016 2015 Raw materials $ 46,951 $ 46,115 Work-in-process 189,596 150,289 Finished goods 110,873 75,279 Total inventory $ 347,420 $ 271,683 In the first quarter of 2016, process qualification production activities commenced in the Company’s Shanbally facility related to Vimizim production. As of September 30, 2016, the value of the qualification campaign was $29.8 million, which was capitalized as inventory because the product is expected to be sold commercially. While the Company believes it is unlikely that the manufacturing process will not be approved for Vimizim production, should that occur, the value of the inventory would be expensed at that time. Inventory as of September 30, 2016, included $31.3 million of pre-launch Brineura (formerly referred to as cerliponase alfa) inventory for production that commenced in the second quarter of 2016. Brineura is an investigational therapy to treat children with CLN2 disease, or late infantile neuronal ceroid lipofuscinosis, a lysosomal storage disorder primarily affecting the brain. The Company must receive marketing approval from the applicable regulators before the Brineura inventory can be sold commercially. Although regulatory approval cannot be assured, the Company expects to receive regulatory approval and realize the costs of the inventory through future sales. The Company believes that all material uncertainties related to the ultimate regulatory approval of Brineura for commercial sale have been significantly reduced based on positive data from Phase I/II clinical trial results and the filings of Biologics License Application (BLA) with the Food and Drug Administration (FDA) and the MAA with the EMA during the second quarter of 2016. In its evaluation, the Company also considered its historical experience with developing and commercially producing similar products for rare genetic disorders. Other Assets consisted of the following: September 30, December 31, 2016 2015 Deposit for business acquisition $ — $ 371,756 Deposits 19,748 8,606 Strategic investments 7,267 18,056 Long-term forward foreign currency exchange contract assets 750 3,533 Other 8,678 6,693 Total other assets $ 36,443 $ 408,644 Included in Deposits is an $8.4 million escrow deposit to purchase land in Shanbally, Ireland. Accounts Payable and Accrued Liabilities consisted of the following: September 30, December 31, 2016 2015 Accounts payable and accrued operating expenses $ 148,773 $ 179,294 Accrued compensation expense 85,219 95,345 Accrued rebates payable 34,184 32,553 Accrued royalties payable 14,183 10,412 Value added taxes payable 7,961 6,377 Accrued income taxes — 59,572 Other 15,809 8,958 Total accounts payable and accrued liabilities $ 306,129 $ 392,511 Accounts payable and accrued operating expenses as of September 30, 2016, included approximately $4.9 million of employee termination benefits accrued as a result of the termination of the Kyndrisa and other exon development programs. This plan was approved and communicated to the impacted employees in the third quarter of 2016. Cash payments to employees will be made through the first quarter of 2017.

CONVERTIBLE DEBT

CONVERTIBLE DEBT	9 Months Ended
	Sep. 30, 2016
Debt Disclosure [Abstract]
CONVERTIBLE DEBT	(11) CONVERTIBLE DEBT The following table summarizes information regarding the Company’s convertible debt: September 30, 2016 December 31, 2015 Convertible Notes due in 2017 $ 22,506 $ 31,430 Unamortized deferred offering costs (46 ) (110 ) Convertible Notes due in 2017, net 22,460 31,320 Convertible Notes due in 2018 374,980 374,980 Unamortized discount (31,219 ) (41,904 ) Unamortized deferred offering costs (3,968 ) (5,415 ) Convertible Notes due in 2018, net 339,793 327,661 Convertible Notes due in 2020 374,993 374,993 Unamortized discount (56,364 ) (65,478 ) Unamortized deferred offering costs (5,244 ) (6,210 ) Convertible Notes due in 2020, net 313,385 303,305 Total convertible debt, net $ 675,638 $ 662,286 Fair value of fixed rate convertible debt Convertible Notes due in 2017 (1) $ 101,789 $ 162,016 Convertible Notes due in 2018 (1) 448,247 482,584 Convertible Notes due in 2020 (1) 469,487 502,701 Total $ 1,019,523 $ 1,147,301 (1) The fair value of the Company’s fixed rate convertible debt is based on open market trades and is classified as Level 1 in the fair value hierarchy. Interest expense on the Company’s convertible debt consisted of the following: Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 Coupon interest $ 2,466 $ 2,283 $ 7,491 $ 7,667 Amortization of issuance costs 826 823 2,476 2,471 Accretion of debt discount 6,688 6,341 19,800 18,773 Total interest expense on convertible debt $ 9,980 $ 9,447 $ 29,767 $ 28,911 During the three and nine months ended September 30, 2016, certain existing holders of the Company’s senior subordinated notes due in 2017 (the 2017 Notes) elected to convert $2.0 million and $8.9 million, respectively, in aggregate principal amount of the 2017 Notes into 97,348 and 438,315 shares of the Company’s common stock, respectively. During the nine months ended September 30, 2015, the Company entered into three separate agreements with certain existing holders of its 2017 Notes pursuant to which such holders converted $8.1 million in aggregate principal amount of the 2017 Notes into 399,469 shares of the Company’s common stock. In addition to issuing the requisite number of shares of the Company’s common stock, the Company also made varying cash payments to the holders totaling $0.2 million in the aggregate, of which $0.2 million was recognized in total as debt conversion expense on the Company’s Condensed Consolidated Statement of Comprehensive Loss for the nine months ended September 30, 2015. See Note 14 to the Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015 for additional information related to the Company’s convertible debt.

DERIVATIVE INSTRUMENTS AND HEDG

DERIVATIVE INSTRUMENTS AND HEDGING STRATEGIES	9 Months Ended
	Sep. 30, 2016
Derivative Instruments And Hedging Activities Disclosure [Abstract]
DERIVATIVE INSTRUMENTS AND HEDGING STRATEGIES	(12) DERIVATIVE INSTRUMENTS AND HEDGING STRATEGIES The Company uses forward foreign currency exchange contracts to hedge certain operational exposures resulting from potential changes in foreign currency exchange rates. Such exposures result from portions of the Company’s forecasted revenues and operating expenses being denominated in currencies other than the U.S. dollar, primarily the Euro. The Company designates certain of these forward foreign currency exchange contracts as hedging instruments and enters into some forward foreign currency exchange contracts that are considered to be economic hedges that are not designated as hedging instruments. Whether designated or undesignated, these forward foreign currency exchange contracts protect against the reduction in value of forecasted foreign currency cash flows resulting from product revenues, royalty revenues, operating expenses and asset or liability positions designated in currencies other than the U.S. dollar. The fair values of forward foreign currency exchange contracts are estimated using current exchange rates and interest rates, and take into consideration the current creditworthiness of the counterparties or the Company, as applicable. Information regarding the specific instruments used by the Company to hedge its exposure to foreign currency exchange rate fluctuations is provided below. See Note 13 to these Condensed Consolidated Financial Statements for additional discussion regarding the fair value of forward foreign currency exchange contracts. The Company enters into forward foreign currency exchange contracts in order to protect against the fluctuations in revenue and operating expenses associated with foreign currency-denominated cash flows. The Company has formally designated these forward foreign currency exchange contracts as cash flow hedges and expects them to be highly effective in offsetting fluctuations in operating expenses denominated in Euros and revenues denominated in currencies other than the U.S. dollar related to changes in foreign currency exchange rates. The following table summarizes the Company’s designated forward foreign currency exchange contracts outstanding as of September 30, 2016 (notional amounts in millions): Aggregate Notional Number of Amount in Foreign Exchange Contracts Contracts Foreign Currency Maturity Euros - Purchase 84 92.5 Oct. 2016 - Sep. 2019 Euros - Sell 280 316.5 Oct. 2016 - Sep. 2019 Canadian Dollars - Sell 6 3.1 Oct. 2016 - Dec. 2016 Colombian Pesos - Sell 3 9,798.0 Oct. 2016 - Dec. 2016 British Pounds - Sell 1 0.6 October 2016 Total 374 The Company also enters into forward foreign currency exchange contracts that are not designated as hedges for accounting purposes. The changes in fair value of these forward foreign currency exchange contracts are included as a part of selling, general and administrative (SG&A) expense in the Company’s Condensed Consolidated Statements of Comprehensive Loss. The following table summarizes the Company’s non-designated forward foreign currency exchange contracts outstanding as of September 30, 2016 (notional amounts in millions): Aggregate Notional Number of Amount in Foreign Exchange Contracts Contracts Foreign Currency Maturity Euros - Purchase 1 99.4 October 2016 British Pounds - Sell 1 6.9 October 2016 Total 2 The maximum length of time over which the Company is hedging its exposure to the reduction in value of forecasted foreign currency revenues through forward foreign currency exchange contracts is through September 2019. Over the next twelve months, the Company expects to reclassify $0.5 million from accumulated other comprehensive income to earnings as the forecasted revenue and operating expense transactions occur. The fair value carrying amounts of the Company’s derivative instruments were as follows: Asset Derivatives Liability Derivatives September 30, 2016 September 30, 2016 Balance Sheet Location Fair Value Balance Sheet Location Fair Value Derivatives designated as hedging instruments: Forward foreign currency exchange contracts Other current assets $ 4,785 Accounts payable and accrued liabilities $ 3,290 Forward foreign currency exchange contracts Other assets 750 Other long- term liabilities 1,979 Total 5,535 5,269 Derivatives not designated as hedging instruments: Forward foreign currency exchange contracts Other current assets 25 Accounts payable and accrued liabilities 65 Forward foreign currency exchange contracts Other assets — Other long- term liabilities — Total 25 65 Total value of derivative contracts $ 5,560 $ 5,334 Asset Derivatives Liability Derivatives December 31, 2015 December 31, 2015 Balance Sheet Location Fair Value Balance Sheet Location Fair Value Derivatives designated as hedging instruments: Forward foreign currency exchange contracts Other current assets $ 10,478 Accounts payable and accrued liabilities $ 1,986 Forward foreign currency exchange contracts Other assets 3,533 Other long- term liabilities 3,057 Total 14,011 5,043 Derivatives not designated as hedging instruments: Forward foreign currency exchange contracts Other current assets — Accounts payable and accrued liabilities 22 Total — 22 Total value of derivative contracts $ 14,011 $ 5,065 The effect of the Company’s derivative instruments on the Condensed Consolidated Financial Statements for the three and nine months ended September 30, 2016 and 2015 was as follows: Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 Derivatives Designated as Hedging Instruments: Net gain (loss) recognized in Other Comprehensive Income (OCI) (1) $ (1,984 ) $ 3,126 $ (5,857 ) $ 14,191 Net gain reclassified from accumulated OCI into earnings (2) 1,486 5,187 4,616 15,084 Net gain (loss) recognized in net loss (3) 9 (264 ) 5,276 (404 ) Derivatives Not Designated as Hedging Instruments: Net gain (loss) recognized in net loss (4) $ 826 $ (514 ) $ (2,446 ) $ 6,052 (1) Net change in the fair value of the effective portion classified as OCI. (2) Effective portion classified as Net Product Revenues and SG&A expense. (3) Ineffective portion and amount excluded from effectiveness testing classified as SG&A expense. (4) Classified as SG&A expense. At September 30, 2016 and December 31, 2015, accumulated other comprehensive income associated with forward foreign currency exchange contracts qualifying for hedge accounting treatment was a gain of $1.2 million and $13.6 million, respectively. The Company is exposed to counterparty credit risk on all of its derivative financial instruments. The Company has established and maintains strict counterparty credit guidelines and enters into hedges only with financial institutions that are investment grade or better to minimize the Company ’

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	(13) FAIR VALUE MEASUREMENTS The Company measures certain financial assets and liabilities at fair value on a recurring basis, including available-for-sale fixed income securities and foreign currency derivatives. The tables below present the fair value of these financial assets and liabilities determined using the following input levels. Fair Value Measurements at September 30, 2016 Quoted Price in Active Markets For Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Assets: Cash and cash equivalents: Overnight deposits $ 246,568 $ — $ — $ 246,568 Money market instruments — 460,781 — 460,781 Total cash and cash equivalents 246,568 460,781 — 707,349 Available-for-sale securities: Short-term: Certificates of deposit — 2,800 — 2,800 Corporate debt securities — 139,073 — 139,073 Commercial paper — 16,692 — 16,692 U.S. government agency securities — 168,934 — 168,934 Long-term: Corporate debt securities — 281,894 — 281,894 U.S. government agency securities — 80,928 — 80,928 Greek government-issued bonds — 134 — 134 Total available-for-sale securities — 690,455 — 690,455 Other current assets: Nonqualified Deferred Compensation Plan assets — 309 — 309 Forward foreign currency exchange contract (1) — 4,810 — 4,810 Restricted investments (2) — 4,052 — 4,052 Total other current assets — 9,171 — 9,171 Other assets: Nonqualified Deferred Compensation Plan assets — 8,562 — 8,562 Forward foreign currency exchange contract (1) — 750 — 750 Strategic investment (3) 7,267 — — 7,267 Total other assets 7,267 9,312 — 16,579 Total assets $ 253,835 $ 1,169,719 $ — $ 1,423,554 Liabilities: Current liabilities: Nonqualified Deferred Compensation Plan liability $ 4,008 $ 309 $ — $ 4,317 Forward foreign currency exchange contract (1) — 3,355 — 3,355 Contingent acquisition consideration payable — — 48,746 48,746 Total current liabilities 4,008 3,664 48,746 56,418 Other long-term liabilities: Nonqualified Deferred Compensation Plan liability $ 19,394 $ 8,562 — 27,956 Forward foreign currency exchange contract (1) — 1,979 — 1,979 Contingent acquisition consideration payable — — 122,644 122,644 Total other long-term liabilities 19,394 10,541 122,644 152,579 Total liabilities $ 23,402 $ 14,205 $ 171,390 $ 208,997 Fair Value Measurements at December 31, 2015 Quoted Price in Active Markets For Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Assets: Cash and cash equivalents: Overnight deposits $ 290,731 $ — $ — $ 290,731 Money market instruments — 106,309 — 106,309 Total cash and cash equivalents 290,731 106,309 — 397,040 Available-for-sale securities: Short-term: Certificates of deposit — 56,951 — 56,951 Corporate debt securities — 42,673 — 42,673 Commercial paper — 12,733 — 12,733 U.S. government agency securities — 83,222 — 83,222 Long-term: Certificates of deposit — 6,969 — 6,969 Corporate debt securities — 315,240 — 315,240 U.S. government agency securities — 103,316 — 103,316 Greek government-issued bonds — 127 — 127 Total available-for-sale securities — 621,231 — 621,231 Other current assets: Nonqualified Deferred Compensation Plan assets — 440 — 440 Forward foreign currency exchange contract (1) — 10,478 — 10,478 Restricted investments (2) — 7,348 — 7,348 Total other current assets — 18,266 — 18,266 Other assets: Nonqualified Deferred Compensation Plan assets — 6,362 — 6,362 Forward foreign currency exchange contract (1) — 3,533 — 3,533 Strategic investment (3) 18,056 — — 18,056 Total other assets 18,056 9,895 — 27,951 Total assets $ 308,787 $ 755,701 $ — $ 1,064,488 Liabilities: Current liabilities: Nonqualified Deferred Compensation Plan liability $ 1,151 $ 440 $ — $ 1,591 Forward foreign currency exchange contract (1) — 2,008 — 2,008 Contingent acquisition consideration payable — — 52,946 52,946 Total current liabilities 1,151 2,448 52,946 56,545 Other long-term liabilities: Nonqualified Deferred Compensation Plan liability 24,341 6,362 — 30,703 Forward foreign currency exchange contract (1) — 3,057 — 3,057 Contingent acquisition consideration payable — — 32,663 32,663 Total other long-term liabilities 24,341 9,419 32,663 66,423 Total liabilities $ 25,492 $ 11,867 $ 85,609 $ 122,968 (1) See Note 12 to these Condensed Consolidated Financial Statements for further information regarding the derivative instruments. (2) The restricted investments at September 30, 2016 and December 31, 2015 secure the Company’s irrevocable standby letter of credit obtained in connection with certain commercial agreements. (3) The Company has investments in marketable equity securities measured using quoted prices in an active market that are considered strategic investments. See Note 7 to these Condensed Consolidated Financial Statements for additional discussion regarding the Company’s strategic investments. There were no transfers between levels during the three and nine months ended September 30, 2016. The Company’s Level 2 securities are valued using third-party pricing sources. The pricing services utilize industry standard valuation models, including both income and market-based approaches, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include reported trades of and broker/dealer quotes on the same or similar securities, issuer credit spreads, benchmark securities, prepayment/default projections based on historical data and other observable inputs. The Company validates the prices provided by its third-party pricing services by understanding the models used, obtaining market values from other pricing sources, analyzing pricing data in certain instances and confirming those securities traded in active markets. See Note 7 to these Condensed Consolidated Financial Statements for further information regarding the Company’s financial instruments. Liabilities measured at fair value using Level 3 inputs consisted of contingent acquisition consideration payable and asset retirement obligations. The Company ’ ’ ’ Contingent acquisition consideration payable at December 31, 2015 $ 85,609 Addition of contingent acquisition consideration payable related to the purchase of the Merck PKU Business 138,974 Changes in the fair value of contingent acquisition consideration payable for continuing development programs 7,032 Reduction of fair value related to termination of Kyndrisa development program (43,652 ) Reduction of fair value related to termination of reveglucosidase alfa development program (20,334 ) Foreign exchange remeasurement of Euro denominated contingent acquisition consideration payable 3,761 Contingent acquisition consideration payable at September 30, 2016 $ 171,390 Under certain of the Company ’ Asset retirement obligations at December 31, 2015 $ 4,704 Accretion expense 79 Reversals (250 ) Asset retirement obligations at September 30, 2016 $ 4,533 The Company acquired intangible assets as a result of various business acquisitions. The estimated fair value of these long-lived assets was measured using Level 3 inputs as of the acquisition date.

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION	9 Months Ended
	Sep. 30, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
STOCK-BASED COMPENSATION	(14) STOCK-BASED COMPENSATION The Company’s stock-based compensation plans include the Amended and Restated 2006 Share Incentive Plan (the Share Incentive Plan) and the ESPP. The Company previously had a 2014 Inducement Plan and a 2012 Inducement Plan, which expired in June 2015 and May 2013, respectively. The Company’s stock-based compensation plans are administered by the Compensation Committee of the Company’s Board of Directors (the Board), which selects persons to receive awards and determines the number of shares subject to each award and the terms, conditions, performance measures and other provisions of the awards. See Note 18 to the Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015 for additional information related to these stock-based compensation plans. Determining the Fair Value of Stock Options and Stock Purchase Rights The fair value of each option award is estimated on the date of grant using the Black-Scholes valuation model and the assumptions noted in the tables below. The expected life of options is based on observed historical exercise patterns. Groups of employees that have similar historical exercise patterns were considered separately for valuation purposes, and as of September 30, 2016 the Company has identified two groups with distinctly different exercise patterns. The two groups identified are executive and non-executive employees. The executive employee group has a history of holding options for longer periods than non-executive employees. The expected volatility of stock options is based upon the weighted average of the historical volatility of the Company s common stock. The risk-free interest rate is based on the implied yield on a U.S. Treasury zero-coupon issue with a remaining term equal to the expected term of the option. The dividend yield reflects that the Company has not paid any cash dividends since inception and does not intend to pay any cash dividends in the foreseeable future Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 Expected volatility 38 – 40% 41 – 44% 36 – 44% 39 – 45% Dividend yield 0.0% 0.0% 0.0% 0.0% Expected life 5.0 – 6.7 years 6.9 – 8.0 years 5.0 – 8.1 years 6.4 – 8.0 years Risk-free interest rate 1.1 – 1.4% 1.9 – 2.2% 1.1 – 2.1% 1.5 – 2.2% During the nine The Company did not issue any new stock purchase rights under the ESPP during the three months ended September 30, 2016. Restricted Stock Unit Awards with Service-Based Vesting Conditions RSUs are generally subject to forfeiture if employment terminates prior to the release of vesting restrictions. The Company expenses the cost of the RSUs, which is determined to be the fair value of the shares of common stock underlying the RSUs at the date of grant, ratably over the period during which the vesting restrictions lapse. During the nine Restricted Stock Unit Awards with Performance and Market-Based Vesting Conditions During 2012 and 2011, p ursuant to the approval of the Board, the Company granted 860,000 RSU awards with performance and market-based vesting conditions (the 2011/2012 Base RSUs) under the Share Incentive Plan and the 2012 Inducement Plan to certain executive officers. The 2011/2012 Base RSUs had a weighted-average grant date fair value of $34.66 and vested on February 29, 2016, based upon the achievement of the Vimizim approval and the 2015 revenue goal. The Company determined the number of Base RSUs that were earned on the vesting date (the Earned RSUs) and to determine the total number of RSUs to be awarded the Earned RSUs were multiplied by the Total Shareholder Return multiplier of 124% resulting in the issuance of 799,800 shares on February 29, 2016. Restricted Stock Unit Awards with Performance Conditions On March 15, 2016, pursuant to Board approval, the Company granted 130,310 RSU awards with performance-vesting conditions (the 2016 Base RSUs) under the Share Incentive Plan to certain executive officers. The vesting of the 2016 Base RSUs under this specific grant is contingent upon the achievement of a 2016 revenue target and a three-year service period. The number of RSUs to be awarded from the 2016 Base RSUs upon achievement of the performance condition shall be calculated by multiplying the 2016 Base RSUs by a revenue multiplier (determined based on the Company’s performance against the revenue target), which could range between 80% and 120%. Stock-based compensation for these awards will be recognized over the service period beginning in the period the Company determines it is probable that the revenue target will be achieved. The cost of the 2016 Base RSUs was determined to be $83.43 per RSU, based on the fair value of the common stock underlying the 2016 Base RSUs on the grant date. The Company evaluated the 2016 revenue target in the context of its current 2016 revenue forecast and related confidence level in the forecast, and determined that attainment of the revenue target was probable for accounting purposes in the first quarter of 2016. As a result, the Company recognized $1.0 million and $2.1 million of compensation expense related to these awards during the three and nine months ended September 30, 2016, respectively. On March 3, 2015, pursuant to Board approval, the Company granted 58,300 RSU awards with performance-vesting conditions (the 2015 Base RSUs) and a three-year service period, under the Share Incentive Plan, to certain executive officers . ’ Compensation expense included in the Company’s Condensed Consolidated Statements of Comprehensive Loss for all stock-based compensation arrangements was as follows: Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 Cost of sales $ 2,092 $ 1,386 $ 5,943 $ 4,484 R&D 14,165 12,578 42,929 34,972 SG&A 16,645 14,794 48,348 41,503 Total stock-based compensation expense $ 32,902 $ 28,758 $ 97,220 $ 80,959 Stock-based compensation expense of $9.0 million and $8.3 million was capitalized into inventory for the nine months ended September 30, 2016 and 2015, respectively. Capitalized stock-based compensation is recognized as Cost of Sales when the related product is sold.

COMPREHENSIVE LOSS

COMPREHENSIVE LOSS	9 Months Ended
	Sep. 30, 2016
Equity [Abstract]
COMPREHENSIVE LOSS	(15) COMPREHENSIVE LOSS The following table summarizes amounts reclassified out of Accumulated Other Comprehensive Income (AOCI) and their effect on the Company’s Condensed Consolidated Statements of Comprehensive Loss for the three and nine months ended September 30, 2016 and 2015. Three Months Ended September 30, Nine Months Ended September 30, Consolidated Statement of Details about AOCI Components 2016 2015 2016 2015 Comprehensive Loss Classification Gains (losses) on cash flow hedges: Forward foreign currency exchange contracts $ 1,436 $ 4,411 $ 4,036 $ 13,660 Net product revenues Forward foreign currency exchange contracts 50 776 4,874 1,424 SG&A Gain (loss) on sale of available-for-sale securities 7 14 (2,020 ) 3,036 Other income (expense) Less: Income tax effect of the above 2 5 (735 ) 1,098 Provision for (Benefit from) income taxes $ 1,491 $ 5,196 $ 7,625 $ 17,022 Net loss The following tables summarize changes in the accumulated balances for each component of AOCI, including current period other comprehensive income and reclassifications out of AOCI for the three and nine months ended September 30, 2016 and 2015. Three Months Ended September 30, 2016 Unrealized Gains (Losses) on Cash Flow Hedges Unrealized Gains (Losses) on Available-for-Sale Securities Foreign Currency Items Total AOCI balance at June 30, 2016 $ 2,305 $ 2,231 $ (8 ) $ 4,528 Other comprehensive income (loss) before reclassifications (1,984 ) 1,738 (1 ) (247 ) Less net gain reclassified from AOCI 1,486 7 — 1,493 Tax effect — (630 ) — (630 ) Net current-period other comprehensive income (loss) (3,470 ) 1,101 (1 ) (2,370 ) AOCI balance at September 30, 2016 $ (1,165 ) $ 3,332 $ (9 ) $ 2,158 Nine Months Ended September 30, 2016 Unrealized Gains (Losses) on Cash Flow Hedges Unrealized Gains (Losses) on Available-for-Sale Securities Foreign Currency Items Total AOCI balance at December 31, 2015 $ 13,602 $ 7,441 $ (10 ) $ 21,033 Other comprehensive income (loss) before reclassifications (5,857 ) (8,477 ) 1 (14,333 ) Less net gain (loss) reclassified from AOCI 8,910 (2,020 ) — 6,890 Tax effect — 2,348 — 2,348 Net current-period other comprehensive income (loss) (14,767 ) (4,109 ) 1 (18,875 ) AOCI balance at September 30, 2016 $ (1,165 ) $ 3,332 $ (9 ) $ 2,158 Three Months Ended September 30, 2015 Unrealized Gains (Losses) on Cash Flow Hedges Unrealized Gains (Losses) on Available-for-Sale Securities Foreign Currency Items Total AOCI balance at June 30, 2015 $ 17,074 $ 15,336 $ 51 $ 32,461 Other comprehensive income (loss) before reclassifications 3,126 (8,159 ) 1 (5,032 ) Less gain reclassified from AOCI 5,187 14 — 5,201 Tax effect — 2,956 — 2,956 Net current-period other comprehensive loss (2,061 ) (5,217 ) 1 (7,277 ) AOCI balance at September 30, 2015 $ 15,013 $ 10,119 $ 52 $ 25,184 Nine Months Ended September 30, 2015 Unrealized Gains (Losses) on Cash Flow Hedges Unrealized Gains (Losses) on Available-for-Sale Securities Foreign Currency Items Total AOCI balance at December 31, 2014 $ 15,906 $ 11,511 $ 49 $ 27,466 Other comprehensive income before reclassifications 14,191 865 3 15,059 Less gain reclassified from AOCI 15,084 3,036 — 18,120 Tax effect — 779 — 779 Net current-period other comprehensive income (loss) (893 ) (1,392 ) 3 (2,282 ) AOCI balance at September 30, 2015 $ 15,013 $ 10,119 $ 52 $ 25,184

REVENUE AND CREDIT CONCENTRATIO

REVENUE AND CREDIT CONCENTRATIONS	9 Months Ended
	Sep. 30, 2016
Risks And Uncertainties [Abstract]
REVENUE AND CREDIT CONCENTRATIONS	(16) REVENUE AND CREDIT CONCENTRATIONS Net Product Revenue— The Company considers there to be revenue concentration risks for regions where net product revenue exceeds 10% of consolidated net product revenue. The concentration of the Company’s net product revenue within the regions below may have a material adverse effect on the Company’s revenue and results of operations if sales in the respective regions experience difficulties. The table below summarizes consolidated net product revenue concentrations based on patient location for Vimizim, Naglazyme, Kuvan and Firdapse which are sold directly by the Company and global sales of Aldurazyme which is marketed by Genzyme Corporation (Genzyme). Genzyme is the Company’s sole customer for Aldurazyme and is responsible for marketing and selling Aldurazyme to third parties. Net product revenues from Genzyme consisted of royalties on worldwide net Aldurazyme sales and incremental product transfer revenues. Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 Net product revenues marketed by the Company United States 38 % 44 % 38 % 38 % Europe 23 % 21 % 23 % 19 % Latin America 14 % 12 % 13 % 19 % Rest of world 16 % 13 % 19 % 15 % Total net product revenue marketed by the Company 91 % 90 % 93 % 91 % Aldurazyme net product revenues marketed by Genzyme 9 % 10 % 7 % 9 % Total net product revenues 100 % 100 % 100 % 100 % The following table illustrates the percentage of the Company’s consolidated net product revenues attributed to the Company’s largest customers for the three and nine months ended September 30, 2016 and 2015. Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 Customer A 19 % 15 % 19 % 14 % Customer B 13 % 9 % 13 % 11 % Customer C 6 % 6 % 6 % 13 % Customer D 10 % 13 % 10 % 5 % Total 48 % 43 % 48 % 43 % On a consolidated basis, the Company’s two largest customers accounted for 22% and 19% of the September 30, 2016 accounts receivable balance, respectively, compared to December 31, 2015, when the two largest customers accounted for 37% and 18% of the accounts receivable balance, respectively. Genzyme is the Company’s sole customer for Aldurazyme and is responsible for marketing and selling Aldurazyme to third-parties. As of September 30, 2016, and December 31, 2015, the accounts receivable balance for Genzyme included $22.6 million and $36.1 million, respectively, of unbilled accounts receivable related to net incremental Aldurazyme product transfers to Genzyme. The Company does not require collateral from its customers, but does perform periodic credit evaluations of its customers’ financial condition and requires immediate payment in certain circumstances. The Company is subject to credit risk from accounts receivable related to product sales. The majority of the Company ’ ’ ’ As of September 30, 2016, the Company’s accounts receivable in certain European countries, specifically Italy, Spain, Portugal, Greece and Russia, totaled approximately $26.4 million, of which $2.6 million were greater than 90 days past due. The Company also sells its products in other countries that face economic crises and local currency devaluation. Although the Company has historically collected receivables from customers in those countries, sustained weakness or further deterioration of the local economies and currencies may cause customers in those countries to be unable to pay for the Company ’

SEGMENT INFORMATION

SEGMENT INFORMATION	9 Months Ended
	Sep. 30, 2016
Segment Reporting [Abstract]
SEGMENT INFORMATION	(17) SEGMENT INFORMATION The Company operates in one business segment, which primarily focuses on the development and commercialization of innovative biopharmaceuticals for serious diseases and medical conditions. All products are included in one segment because the majority of the Company ’ Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 Net product revenues by product: Vimizim $ 80,903 65,106 $ 260,310 $ 169,608 Naglazyme 77,728 54,131 221,575 243,386 Kuvan 90,899 64,219 257,806 174,501 Aldurazyme 23,751 20,509 58,819 58,991 Firdapse 4,981 3,802 13,685 11,616 Total net product revenues $ 278,262 $ 207,767 $ 812,195 $ 658,102 The following table summarizes total revenues from external customers and collaborative partners by geographic region. Net product revenues by geographic region are based on patient location for Vimizim, Naglazyme, Kuvan and Firdapse and Genzyme ’ ’ Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 Total revenues by geographic region: United States $ 130,356 $ 112,254 $ 365,674 310,209 Europe 62,821 42,816 187,328 124,252 Latin America 38,789 25,588 106,803 127,147 Rest of world 47,930 28,246 156,958 100,351 Total revenues $ 279,896 $ 208,904 $ 816,763 $ 661,959

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	9 Months Ended
	Sep. 30, 2016
Commitments And Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	(18) COMMITMENTS AND CONTINGENCIES Contingencies From time to time the Company is involved in legal actions arising in the normal course of its business. The most significant of these actions are described below. The process of resolving matters through litigation or other means is inherently uncertain and it is possible that an unfavorable resolution of these matters could adversely affect the Company, its results of operations, financial condition and cash flows. The Company’s general practice is to expense legal fees as services are rendered in connection with legal matters, and to accrue for liabilities when losses are probable and reasonably estimable. Paragraph IV Notices The Company received a paragraph IV notice letter, dated January 22, 2015, from Par Pharmaceutical, Inc. (Par), notifying it that Par had filed an abbreviated new drug application (ANDA) seeking approval of a proposed generic version of Kuvan (sapropterin dihydrochloride) 100 mg oral tablets prior to the expiration of the Company’s patents listed in the FDA’s Approved Drug Products with Therapeutic Equivalence Evaluations (the Orange Book). Together with Merck & Cie, on March 6, 2015, the Company filed a lawsuit against Par in the U.S. District Court for the District of New Jersey alleging infringement of its patents relating to Kuvan tablets and seeking an injunction to prevent Par from introducing a generic version of Kuvan tablets that would infringe its patents prior to their expiration. The filing of that lawsuit triggered the automatic 30-month stay on the approval of Par’s ANDA in accordance with the Hatch-Waxman Act, which expires in July 2017. In response, Par alleged, inter alia, that the asserted patents are not infringed and/or are invalid. The Company also received a paragraph IV notice letter, dated January 14, 2016, from Par, notifying the Company that Par has filed a separate ANDA seeking approval of a proposed generic version of Kuvan 100 mg oral powder prior to the expiration of the Company’s patents listed in the FDA's Orange Book. On February 22, 2016, the Company filed a lawsuit against Par in the U.S. District Court for the District of New Jersey alleging infringement of its patents relating to Kuvan powder and seeking an injunction to prevent Par from introducing a generic version of Kuvan powder that would infringe its patents prior to their expiration. The filing of that lawsuit triggered the automatic 30-month stay on the approval of Par’s ANDA in accordance with the Hatch-Waxman Act, which expires in July 2018. In response, Par alleged, inter alia The two cases against Par have been consolidated in the District of New Jersey. The court held a claim construction hearing on May 5, 2016 but has not yet issued its ruling. Fact discovery closed in September 2016 and trial is scheduled for June 2017. SEC Subpoena In August 2016, the Company received a subpoena from the staff of the SEC requesting that the Company produce documents in connection with a non-public, fact-finding inquiry related to its former drisapersen program. The letter enclosing the subpoena states that the investigation and the subpoena do not mean that the Company or anyone else has broken the law, or that the SEC has a negative opinion of any person, entity or security. The Company intends to cooperate fully with the SEC in this matter. The Company is not able to predict whether any proceeding may be instituted in connection with the subpoena, or the outcome of any proceeding that may be instituted. Contingent Payments As of September 30, 2016, the Company is subject to contingent payments totaling approximately $754.4 million upon achievement of certain development and regulatory activities and commercial sales and licensing milestones if they occur before certain dates in the future. Of this amount, $207.6 million (or €185 million based on the exchange rate of 1.12 USD per Euro in effect on September 30, 2016) relates to the Merck PKU Business acquisition and $58.2 million relates to programs that are no longer being developed. As of September 30, 2016, the Company has recorded $171.4 million of contingent acquisition consideration payable on its Condensed Consolidated Balances Sheets in Short-term and Long-term Contingent Acquisition Consideration Payable, of which $48.7 million is expected to be paid in the next twelve months. Other Commitments In the normal course of business, the Company enters into various firm purchase commitments primarily related to active pharmaceutical ingredients September 30, 2016

BENEFIT FROM INCOME TAXES

BENEFIT FROM INCOME TAXES	9 Months Ended
	Sep. 30, 2016
Income Tax Disclosure [Abstract]
BENEFIT FROM INCOME TAXES	The Company has historically computed its interim period benefit from income taxes by applying its forecasted effective tax rate to year-to-date earnings. However, due to a significant amount of U.S. permanent differences relative to the amount of U.S. forecasted income used in computing the effective tax rate, the effective tax rate can be highly sensitive to minor fluctuations in U.S forecasted income. As such, the Company has computed the U.S component of the consolidated benefit from income taxes for the three and nine months ended September 30, 2016 using an actual year-to-date tax calculation. Foreign tax expense was computed using a forecasted annual effective tax rate for the three and nine months ended September 30, 2016. The consolidated benefit from income taxes for the three and nine ended September 30, 2015 was computed using a forecasted annual effective tax rate.

ACQUISITIONS (Tables)

ACQUISITIONS (Tables)	9 Months Ended
	Sep. 30, 2016
Business Combinations [Abstract]
Summary of Estimated Fair Values of Assets Acquired and Liabilities Assumed	The following table presents the preliminary allocation of the purchase consideration for the Merck PKU Business Cash payments $ 374,545 Estimated fair value of contingent acquisition consideration payable 138,974 Total consideration $ 513,519 Kuvan intangible assets $ 172,961 Pegvaliase IPR&D 326,359 Inventory 14,199 Total identifiable assets acquired $ 513,519
Summary of Pro Forma Financial Information	The following unaudited pro forma financial information presents the combined results of operations of the Company and the Merck PKU Business as if the acquisition occurred on January 1, 2015. This unaudited pro forma financial information is presented for informational purposes only and is not necessarily indicative of the results of future operations that would have been achieved had the acquisitions taken place at the beginning of 2015. Three Months Ended September 30, Nine Months Ended September 30, 2015 2015 Total revenues $ 225,697 $ 713,930 Net loss $ (84,395 ) $ (220,465 ) Net loss per share, basic $ (0.52 ) $ (1.38 ) Net loss per share, diluted $ (0.55 ) $ (1.38 ) Weighted average common shares outstanding, basic 160,886 159,647 Weighted average common shares outstanding, diluted 161,134 159,647

NET LOSS PER COMMON SHARE (Tabl

NET LOSS PER COMMON SHARE (Tables)	9 Months Ended
	Sep. 30, 2016
Earnings Per Share [Abstract]
Computation of Basic and Diluted Earnings per Common Share	The following table sets forth the computation of basic and diluted earnings per common share (in thousands of common shares): Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 Numerator: Net loss, basic $ (42,797 ) $ (90,926 ) $ (551,499 ) $ (240,416 ) Gain on common stock held by the NQDC — (4,980 ) (1,753 ) — Net loss, diluted $ (42,797 ) $ (95,906 ) $ (553,252 ) $ (240,416 ) Denominator: Weighted-average common shares outstanding, basic 167,714 160,886 163,963 159,647 Effect of dilutive securities: Common shares held by the NQDC — 248 253 — Weighted-average common shares outstanding, diluted 167,714 161,134 164,216 159,647 Net loss per common share, basic $ (0.26 ) $ (0.57 ) $ (3.36 ) $ (1.51 ) Net loss per common share, diluted $ (0.26 ) $ (0.60 ) $ (3.37 ) $ (1.51 )
Schedule Of Anti-Dilutive Common Stock Excluded From Computation of Diluted Net Loss Per Share	In addition to the equity instruments included in the table above, the table below presents the shares of common stock that were excluded from the computation as they were anti-dilutive using the treasury stock method (in thousands of shares): Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 Options to purchase common stock 9,610 10,503 9,610 10,503 Common stock issuable under the 2017 Notes 1,105 1,553 1,105 1,553 Common stock issuable under the 2018 and 2020 Notes 7,966 7,966 7,966 7,966 Unvested restricted stock units 2,728 1,757 2,728 1,633 Common stock potentially issuable for ESPP purchases 130 229 114 220 Common stock held by the NQDC 253 — — 248 Total number of potentially issuable shares 21,792 22,008 21,523 22,123

INVESTMENTS (Tables)

INVESTMENTS (Tables)	9 Months Ended
	Sep. 30, 2016
Investments Schedule [Abstract]
Amortized Cost, Gross Unrealized Holding Gain or Loss, and Fair Value of Available For Sale Security by Major Security type	The amortized cost, gross unrealized holding gains or losses, and fair value of the Company’s available-for-sale securities by major security type at September 30, 2016 and December 31, 2015 are summarized in the tables below: Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Aggregate Fair Value at September 30, 2016 Certificates of deposit $ 2,800 $ — $ — $ 2,800 Corporate debt securities 420,259 873 (165 ) 420,967 Commercial paper 16,692 — — 16,692 U.S. government agency securities 249,674 190 (2 ) 249,862 Greek government-issued bonds 52 82 — 134 Total $ 689,477 $ 1,145 $ (167 ) $ 690,455 Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Aggregate Fair Value at December 31, 2015 Certificates of deposit $ 63,919 $ 1 $ — $ 63,920 Corporate debt securities 358,625 20 (732 ) 357,913 Commercial paper 12,733 — — 12,733 U.S. government agency securities 186,882 — (344 ) 186,538 Greek government-issued bonds 48 79 — 127 Total $ 622,207 $ 100 $ (1,076 ) $ 621,231
Fair Values of Available-For-Sale Securities by Contractual Maturity	The fair values of available-for-sale securities by contractual maturity were as follows: September 30, December 31, 2016 2015 Maturing in one year or less $ 327,499 $ 195,579 Maturing after one year through five years 362,956 425,652 Total $ 690,455 $ 621,231

INTANGIBLE ASSETS (Tables)

INTANGIBLE ASSETS (Tables)	9 Months Ended
	Sep. 30, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets	Intangible assets consisted of the following: September 30, December 31, 2016 2015 Intangible assets: Finite-lived intangible assets $ 305,122 $ 129,572 Indefinite-lived intangible assets 332,199 607,548 Gross intangible assets: 637,321 737,120 Less: Accumulated amortization (75,934 ) (53,124 ) Net carrying value $ 561,387 $ 683,996

PROPERTY, PLANT AND EQUIPMENT (

PROPERTY, PLANT AND EQUIPMENT (Tables)	9 Months Ended
	Sep. 30, 2016
Property Plant And Equipment [Abstract]
Schedule of Property Plant and Equipment Net	Property, plant and equipment, net consisted of the following: September 30, December 31, 2016 2015 Building and improvements $ 505,894 $ 442,100 Manufacturing and laboratory equipment 229,818 145,313 Computer hardware and software 123,557 113,442 Leasehold improvements 44,802 44,247 Furniture and equipment 26,359 22,817 Land improvements 4,881 4,881 Land 45,727 45,727 Construction-in-progress 76,992 164,283 1,058,030 982,810 Less: Accumulated depreciation (328,194 ) (278,603 ) Total property, plant and equipment, net $ 729,836 $ 704,207

SUPPLEMENTAL BALANCE SHEET IN31

SUPPLEMENTAL BALANCE SHEET INFORMATION (Tables)	9 Months Ended
	Sep. 30, 2016
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Schedule Of Inventory	Inventory consisted of the following: September 30, December 31, 2016 2015 Raw materials $ 46,951 $ 46,115 Work-in-process 189,596 150,289 Finished goods 110,873 75,279 Total inventory $ 347,420 $ 271,683
Schedule of Other Assets	Other Assets consisted of the following: September 30, December 31, 2016 2015 Deposit for business acquisition $ — $ 371,756 Deposits 19,748 8,606 Strategic investments 7,267 18,056 Long-term forward foreign currency exchange contract assets 750 3,533 Other 8,678 6,693 Total other assets $ 36,443 $ 408,644
Schedule of Accounts Payable and Accrued Liabilities	Accounts Payable and Accrued Liabilities consisted of the following: September 30, December 31, 2016 2015 Accounts payable and accrued operating expenses $ 148,773 $ 179,294 Accrued compensation expense 85,219 95,345 Accrued rebates payable 34,184 32,553 Accrued royalties payable 14,183 10,412 Value added taxes payable 7,961 6,377 Accrued income taxes — 59,572 Other 15,809 8,958 Total accounts payable and accrued liabilities $ 306,129 $ 392,511

CONVERTIBLE DEBT (Tables)

CONVERTIBLE DEBT (Tables)	9 Months Ended
	Sep. 30, 2016
Debt Disclosure [Abstract]
Summary of Convertible Debt	The following table summarizes information regarding the Company’s convertible debt: September 30, 2016 December 31, 2015 Convertible Notes due in 2017 $ 22,506 $ 31,430 Unamortized deferred offering costs (46 ) (110 ) Convertible Notes due in 2017, net 22,460 31,320 Convertible Notes due in 2018 374,980 374,980 Unamortized discount (31,219 ) (41,904 ) Unamortized deferred offering costs (3,968 ) (5,415 ) Convertible Notes due in 2018, net 339,793 327,661 Convertible Notes due in 2020 374,993 374,993 Unamortized discount (56,364 ) (65,478 ) Unamortized deferred offering costs (5,244 ) (6,210 ) Convertible Notes due in 2020, net 313,385 303,305 Total convertible debt, net $ 675,638 $ 662,286 Fair value of fixed rate convertible debt Convertible Notes due in 2017 (1) $ 101,789 $ 162,016 Convertible Notes due in 2018 (1) 448,247 482,584 Convertible Notes due in 2020 (1) 469,487 502,701 Total $ 1,019,523 $ 1,147,301 (1) The fair value of the Company’s fixed rate convertible debt is based on open market trades and is classified as Level 1 in the fair value hierarchy.
Summary of Convertible Debt Interest Expense	Interest expense on the Company’s convertible debt consisted of the following: Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 Coupon interest $ 2,466 $ 2,283 $ 7,491 $ 7,667 Amortization of issuance costs 826 823 2,476 2,471 Accretion of debt discount 6,688 6,341 19,800 18,773 Total interest expense on convertible debt $ 9,980 $ 9,447 $ 29,767 $ 28,911

DERIVATIVE INSTRUMENTS AND HE33

DERIVATIVE INSTRUMENTS AND HEDGING STRATEGIES (Tables)	9 Months Ended
	Sep. 30, 2016
Derivative [Line Items]
Fair Value Carrying Amount of Derivative Instruments	The fair value carrying amounts of the Company’s derivative instruments were as follows: Asset Derivatives Liability Derivatives September 30, 2016 September 30, 2016 Balance Sheet Location Fair Value Balance Sheet Location Fair Value Derivatives designated as hedging instruments: Forward foreign currency exchange contracts Other current assets $ 4,785 Accounts payable and accrued liabilities $ 3,290 Forward foreign currency exchange contracts Other assets 750 Other long- term liabilities 1,979 Total 5,535 5,269 Derivatives not designated as hedging instruments: Forward foreign currency exchange contracts Other current assets 25 Accounts payable and accrued liabilities 65 Forward foreign currency exchange contracts Other assets — Other long- term liabilities — Total 25 65 Total value of derivative contracts $ 5,560 $ 5,334 Asset Derivatives Liability Derivatives December 31, 2015 December 31, 2015 Balance Sheet Location Fair Value Balance Sheet Location Fair Value Derivatives designated as hedging instruments: Forward foreign currency exchange contracts Other current assets $ 10,478 Accounts payable and accrued liabilities $ 1,986 Forward foreign currency exchange contracts Other assets 3,533 Other long- term liabilities 3,057 Total 14,011 5,043 Derivatives not designated as hedging instruments: Forward foreign currency exchange contracts Other current assets — Accounts payable and accrued liabilities 22 Total — 22 Total value of derivative contracts $ 14,011 $ 5,065
Effect of Derivative Instruments	The effect of the Company’s derivative instruments on the Condensed Consolidated Financial Statements for the three and nine months ended September 30, 2016 and 2015 was as follows: Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 Derivatives Designated as Hedging Instruments: Net gain (loss) recognized in Other Comprehensive Income (OCI) (1) $ (1,984 ) $ 3,126 $ (5,857 ) $ 14,191 Net gain reclassified from accumulated OCI into earnings (2) 1,486 5,187 4,616 15,084 Net gain (loss) recognized in net loss (3) 9 (264 ) 5,276 (404 ) Derivatives Not Designated as Hedging Instruments: Net gain (loss) recognized in net loss (4) $ 826 $ (514 ) $ (2,446 ) $ 6,052 (1) Net change in the fair value of the effective portion classified as OCI. (2) Effective portion classified as Net Product Revenues and SG&A expense. (3) Ineffective portion and amount excluded from effectiveness testing classified as SG&A expense. (4) Classified as SG&A expense.
Derivatives Designated As Hedging Instruments
Derivative [Line Items]
Summary of Designated Forward Foreign Currency Exchange Contracts Outstanding	The following table summarizes the Company’s designated forward foreign currency exchange contracts outstanding as of September 30, 2016 (notional amounts in millions): Aggregate Notional Number of Amount in Foreign Exchange Contracts Contracts Foreign Currency Maturity Euros - Purchase 84 92.5 Oct. 2016 - Sep. 2019 Euros - Sell 280 316.5 Oct. 2016 - Sep. 2019 Canadian Dollars - Sell 6 3.1 Oct. 2016 - Dec. 2016 Colombian Pesos - Sell 3 9,798.0 Oct. 2016 - Dec. 2016 British Pounds - Sell 1 0.6 October 2016 Total 374
Not Designated as Hedging Instrument
Derivative [Line Items]
Summary of Designated Forward Foreign Currency Exchange Contracts Outstanding	The following table summarizes the Company’s non-designated forward foreign currency exchange contracts outstanding as of September 30, 2016 (notional amounts in millions): Aggregate Notional Number of Amount in Foreign Exchange Contracts Contracts Foreign Currency Maturity Euros - Purchase 1 99.4 October 2016 British Pounds - Sell 1 6.9 October 2016 Total 2

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Fair Value of Financial Assets and Liabilities	The tables below present the fair value of these financial assets and liabilities determined using the following input levels. Fair Value Measurements at September 30, 2016 Quoted Price in Active Markets For Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Assets: Cash and cash equivalents: Overnight deposits $ 246,568 $ — $ — $ 246,568 Money market instruments — 460,781 — 460,781 Total cash and cash equivalents 246,568 460,781 — 707,349 Available-for-sale securities: Short-term: Certificates of deposit — 2,800 — 2,800 Corporate debt securities — 139,073 — 139,073 Commercial paper — 16,692 — 16,692 U.S. government agency securities — 168,934 — 168,934 Long-term: Corporate debt securities — 281,894 — 281,894 U.S. government agency securities — 80,928 — 80,928 Greek government-issued bonds — 134 — 134 Total available-for-sale securities — 690,455 — 690,455 Other current assets: Nonqualified Deferred Compensation Plan assets — 309 — 309 Forward foreign currency exchange contract (1) — 4,810 — 4,810 Restricted investments (2) — 4,052 — 4,052 Total other current assets — 9,171 — 9,171 Other assets: Nonqualified Deferred Compensation Plan assets — 8,562 — 8,562 Forward foreign currency exchange contract (1) — 750 — 750 Strategic investment (3) 7,267 — — 7,267 Total other assets 7,267 9,312 — 16,579 Total assets $ 253,835 $ 1,169,719 $ — $ 1,423,554 Liabilities: Current liabilities: Nonqualified Deferred Compensation Plan liability $ 4,008 $ 309 $ — $ 4,317 Forward foreign currency exchange contract (1) — 3,355 — 3,355 Contingent acquisition consideration payable — — 48,746 48,746 Total current liabilities 4,008 3,664 48,746 56,418 Other long-term liabilities: Nonqualified Deferred Compensation Plan liability $ 19,394 $ 8,562 — 27,956 Forward foreign currency exchange contract (1) — 1,979 — 1,979 Contingent acquisition consideration payable — — 122,644 122,644 Total other long-term liabilities 19,394 10,541 122,644 152,579 Total liabilities $ 23,402 $ 14,205 $ 171,390 $ 208,997 Fair Value Measurements at December 31, 2015 Quoted Price in Active Markets For Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Assets: Cash and cash equivalents: Overnight deposits $ 290,731 $ — $ — $ 290,731 Money market instruments — 106,309 — 106,309 Total cash and cash equivalents 290,731 106,309 — 397,040 Available-for-sale securities: Short-term: Certificates of deposit — 56,951 — 56,951 Corporate debt securities — 42,673 — 42,673 Commercial paper — 12,733 — 12,733 U.S. government agency securities — 83,222 — 83,222 Long-term: Certificates of deposit — 6,969 — 6,969 Corporate debt securities — 315,240 — 315,240 U.S. government agency securities — 103,316 — 103,316 Greek government-issued bonds — 127 — 127 Total available-for-sale securities — 621,231 — 621,231 Other current assets: Nonqualified Deferred Compensation Plan assets — 440 — 440 Forward foreign currency exchange contract (1) — 10,478 — 10,478 Restricted investments (2) — 7,348 — 7,348 Total other current assets — 18,266 — 18,266 Other assets: Nonqualified Deferred Compensation Plan assets — 6,362 — 6,362 Forward foreign currency exchange contract (1) — 3,533 — 3,533 Strategic investment (3) 18,056 — — 18,056 Total other assets 18,056 9,895 — 27,951 Total assets $ 308,787 $ 755,701 $ — $ 1,064,488 Liabilities: Current liabilities: Nonqualified Deferred Compensation Plan liability $ 1,151 $ 440 $ — $ 1,591 Forward foreign currency exchange contract (1) — 2,008 — 2,008 Contingent acquisition consideration payable — — 52,946 52,946 Total current liabilities 1,151 2,448 52,946 56,545 Other long-term liabilities: Nonqualified Deferred Compensation Plan liability 24,341 6,362 — 30,703 Forward foreign currency exchange contract (1) — 3,057 — 3,057 Contingent acquisition consideration payable — — 32,663 32,663 Total other long-term liabilities 24,341 9,419 32,663 66,423 Total liabilities $ 25,492 $ 11,867 $ 85,609 $ 122,968 (1) See Note 12 to these Condensed Consolidated Financial Statements for further information regarding the derivative instruments. (2) The restricted investments at September 30, 2016 and December 31, 2015 secure the Company’s irrevocable standby letter of credit obtained in connection with certain commercial agreements. (3) The Company has investments in marketable equity securities measured using quoted prices in an active market that are considered strategic investments. See Note 7 to these Condensed Consolidated Financial Statements for additional discussion regarding the Company’s strategic investments.
Liabilities Measured at Fair Value Using Level 3 Inputs	Contingent acquisition consideration payable at December 31, 2015 $ 85,609 Addition of contingent acquisition consideration payable related to the purchase of the Merck PKU Business 138,974 Changes in the fair value of contingent acquisition consideration payable for continuing development programs 7,032 Reduction of fair value related to termination of Kyndrisa development program (43,652 ) Reduction of fair value related to termination of reveglucosidase alfa development program (20,334 ) Foreign exchange remeasurement of Euro denominated contingent acquisition consideration payable 3,761 Contingent acquisition consideration payable at September 30, 2016 $ 171,390
Asset Retirement Obligation Liability and Corresponding Capital Asset	Asset retirement obligations at December 31, 2015 $ 4,704 Accretion expense 79 Reversals (250 ) Asset retirement obligations at September 30, 2016 $ 4,533

STOCK-BASED COMPENSATION (Table

STOCK-BASED COMPENSATION (Tables)	9 Months Ended
	Sep. 30, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Option Valuation Assumptions	The assumptions used to estimate the per share fair value of stock options granted under the 2012 Inducement Plan, the 2014 Inducement Plan and the Share Incentive Plan were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 Expected volatility 38 – 40% 41 – 44% 36 – 44% 39 – 45% Dividend yield 0.0% 0.0% 0.0% 0.0% Expected life 5.0 – 6.7 years 6.9 – 8.0 years 5.0 – 8.1 years 6.4 – 8.0 years Risk-free interest rate 1.1 – 1.4% 1.9 – 2.2% 1.1 – 2.1% 1.5 – 2.2%
Stock-Based Compensation Expense	Compensation expense included in the Company’s Condensed Consolidated Statements of Comprehensive Loss for all stock-based compensation arrangements was as follows: Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 Cost of sales $ 2,092 $ 1,386 $ 5,943 $ 4,484 R&D 14,165 12,578 42,929 34,972 SG&A 16,645 14,794 48,348 41,503 Total stock-based compensation expense $ 32,902 $ 28,758 $ 97,220 $ 80,959

COMPREHENSIVE LOSS (Tables)

COMPREHENSIVE LOSS (Tables)	9 Months Ended
	Sep. 30, 2016
Equity [Abstract]
Amounts Reclassified out of Accumulated Other Comprehensive Income	The following table summarizes amounts reclassified out of Accumulated Other Comprehensive Income (AOCI) and their effect on the Company’s Condensed Consolidated Statements of Comprehensive Loss for the three and nine months ended September 30, 2016 and 2015. Three Months Ended September 30, Nine Months Ended September 30, Consolidated Statement of Details about AOCI Components 2016 2015 2016 2015 Comprehensive Loss Classification Gains (losses) on cash flow hedges: Forward foreign currency exchange contracts $ 1,436 $ 4,411 $ 4,036 $ 13,660 Net product revenues Forward foreign currency exchange contracts 50 776 4,874 1,424 SG&A Gain (loss) on sale of available-for-sale securities 7 14 (2,020 ) 3,036 Other income (expense) Less: Income tax effect of the above 2 5 (735 ) 1,098 Provision for (Benefit from) income taxes $ 1,491 $ 5,196 $ 7,625 $ 17,022 Net loss
Summary of Changes in Accumulated Balances of AOCI Including Current Period Other Comprehensive Income and Reclassifications	The following tables summarize changes in the accumulated balances for each component of AOCI, including current period other comprehensive income and reclassifications out of AOCI for the three and nine months ended September 30, 2016 and 2015. Three Months Ended September 30, 2016 Unrealized Gains (Losses) on Cash Flow Hedges Unrealized Gains (Losses) on Available-for-Sale Securities Foreign Currency Items Total AOCI balance at June 30, 2016 $ 2,305 $ 2,231 $ (8 ) $ 4,528 Other comprehensive income (loss) before reclassifications (1,984 ) 1,738 (1 ) (247 ) Less net gain reclassified from AOCI 1,486 7 — 1,493 Tax effect — (630 ) — (630 ) Net current-period other comprehensive income (loss) (3,470 ) 1,101 (1 ) (2,370 ) AOCI balance at September 30, 2016 $ (1,165 ) $ 3,332 $ (9 ) $ 2,158 Nine Months Ended September 30, 2016 Unrealized Gains (Losses) on Cash Flow Hedges Unrealized Gains (Losses) on Available-for-Sale Securities Foreign Currency Items Total AOCI balance at December 31, 2015 $ 13,602 $ 7,441 $ (10 ) $ 21,033 Other comprehensive income (loss) before reclassifications (5,857 ) (8,477 ) 1 (14,333 ) Less net gain (loss) reclassified from AOCI 8,910 (2,020 ) — 6,890 Tax effect — 2,348 — 2,348 Net current-period other comprehensive income (loss) (14,767 ) (4,109 ) 1 (18,875 ) AOCI balance at September 30, 2016 $ (1,165 ) $ 3,332 $ (9 ) $ 2,158 Three Months Ended September 30, 2015 Unrealized Gains (Losses) on Cash Flow Hedges Unrealized Gains (Losses) on Available-for-Sale Securities Foreign Currency Items Total AOCI balance at June 30, 2015 $ 17,074 $ 15,336 $ 51 $ 32,461 Other comprehensive income (loss) before reclassifications 3,126 (8,159 ) 1 (5,032 ) Less gain reclassified from AOCI 5,187 14 — 5,201 Tax effect — 2,956 — 2,956 Net current-period other comprehensive loss (2,061 ) (5,217 ) 1 (7,277 ) AOCI balance at September 30, 2015 $ 15,013 $ 10,119 $ 52 $ 25,184 Nine Months Ended September 30, 2015 Unrealized Gains (Losses) on Cash Flow Hedges Unrealized Gains (Losses) on Available-for-Sale Securities Foreign Currency Items Total AOCI balance at December 31, 2014 $ 15,906 $ 11,511 $ 49 $ 27,466 Other comprehensive income before reclassifications 14,191 865 3 15,059 Less gain reclassified from AOCI 15,084 3,036 — 18,120 Tax effect — 779 — 779 Net current-period other comprehensive income (loss) (893 ) (1,392 ) 3 (2,282 ) AOCI balance at September 30, 2015 $ 15,013 $ 10,119 $ 52 $ 25,184

REVENUE AND CREDIT CONCENTRAT37

REVENUE AND CREDIT CONCENTRATIONS (Tables) - Net Product Revenue	9 Months Ended
	Sep. 30, 2016
Geographic Concentration Risk
Concentration Risk [Line Items]
Schedules of Consolidated Net Product Revenue Concentration	The table below summarizes consolidated net product revenue concentrations based on patient location for Vimizim, Naglazyme, Kuvan and Firdapse which are sold directly by the Company and global sales of Aldurazyme which is marketed by Genzyme Corporation (Genzyme). Genzyme is the Company’s sole customer for Aldurazyme and is responsible for marketing and selling Aldurazyme to third parties. Net product revenues from Genzyme consisted of royalties on worldwide net Aldurazyme sales and incremental product transfer revenues. Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 Net product revenues marketed by the Company United States 38 % 44 % 38 % 38 % Europe 23 % 21 % 23 % 19 % Latin America 14 % 12 % 13 % 19 % Rest of world 16 % 13 % 19 % 15 % Total net product revenue marketed by the Company 91 % 90 % 93 % 91 % Aldurazyme net product revenues marketed by Genzyme 9 % 10 % 7 % 9 % Total net product revenues 100 % 100 % 100 % 100 %
Customer Concentration Risk
Concentration Risk [Line Items]
Schedules of Consolidated Net Product Revenue Concentration	The following table illustrates the percentage of the Company’s consolidated net product revenues attributed to the Company’s largest customers for the three and nine months ended September 30, 2016 and 2015. Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 Customer A 19 % 15 % 19 % 14 % Customer B 13 % 9 % 13 % 11 % Customer C 6 % 6 % 6 % 13 % Customer D 10 % 13 % 10 % 5 % Total 48 % 43 % 48 % 43 %

SEGMENT INFORMATION (Tables)

SEGMENT INFORMATION (Tables)	9 Months Ended
	Sep. 30, 2016
Segment Reporting [Abstract]
Segment Information by Product Revenue	The Company operates in one business segment, which primarily focuses on the development and commercialization of innovative biopharmaceuticals for serious diseases and medical conditions. All products are included in one segment because the majority of the Company ’ Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 Net product revenues by product: Vimizim $ 80,903 65,106 $ 260,310 $ 169,608 Naglazyme 77,728 54,131 221,575 243,386 Kuvan 90,899 64,219 257,806 174,501 Aldurazyme 23,751 20,509 58,819 58,991 Firdapse 4,981 3,802 13,685 11,616 Total net product revenues $ 278,262 $ 207,767 $ 812,195 $ 658,102
Summary of Total Revenues from External Customers and Collaborative Partners by Geographic Region	The following table summarizes total revenues from external customers and collaborative partners by geographic region. Net product revenues by geographic region are based on patient location for Vimizim, Naglazyme, Kuvan and Firdapse and Genzyme ’ ’ Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 Total revenues by geographic region: United States $ 130,356 $ 112,254 $ 365,674 310,209 Europe 62,821 42,816 187,328 124,252 Latin America 38,789 25,588 106,803 127,147 Rest of world 47,930 28,246 156,958 100,351 Total revenues $ 279,896 $ 208,904 $ 816,763 $ 661,959

Nature of Operations and Busi39

Nature of Operations and Business Risks - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2016Product
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Number of approved products	5

Acquisitions - Additional Infor

Acquisitions - Additional Information (Detail) $ in Thousands, € in Millions	Jan. 02, 2016USD ($)	Sep. 30, 2016USD ($)Country	Jan. 01, 2016USD ($)	Jan. 01, 2016EUR (€)	Dec. 31, 2015USD ($)
Merck PKU Business
Business Acquisition [Line Items]
Business combination transaction costs		$ 300	$ 600		$ 300
Business acquisition, cash paid	$ 374,545
Transfer of marketing authorizations in remaining countries | Country		8
Estimated useful life		through 2,024
Intangible assets amortization method		straight-line basis
Merck Serono
Business Acquisition [Line Items]
Business acquisition, cash paid		$ 374,500
Merck Serono | A&R Kuvan Agreement
Business Acquisition [Line Items]
Maximum potential additional consideration milestone payments | €				€ 60
Merck Serono | Pegvaliase Agreement
Business Acquisition [Line Items]
Maximum potential additional consideration milestone payments | €				€ 125

Acquisitions - Summary of Estim

Acquisitions - Summary of Estimated Fair Values of Assets Acquired and Liabilities Assumed (Detail) - Merck PKU Business - USD ($) $ in Thousands	Jan. 02, 2016	Jan. 01, 2016
Business Acquisition [Line Items]
Cash payments	$ 374,545
Estimated fair value of contingent acquisition consideration payable		$ 138,974
Total consideration	$ 513,519
Kuvan intangible assets		172,961
Pegvaliase IPR&D		326,359
Inventory		14,199
Total identifiable assets acquired		$ 513,519

Acquisitions - Summary of Pro F

Acquisitions - Summary of Pro Forma Financial Information (Detail) - Merck PKU Business - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2015
Business Acquisition [Line Items]
Total revenues	$ 225,697	$ 713,930
Net loss	$ (84,395)	$ (220,465)
Net loss per share, basic	$ (0.52)	$ (1.38)
Net loss per share, diluted	$ (0.55)	$ (1.38)
Weighted average common shares outstanding, basic	160,886	159,647
Weighted average common shares outstanding, diluted	161,134	159,647

Computation of Basic and Dilute

Computation of Basic and Diluted Earnings per Common Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share [Abstract]
Net loss, basic	$ (42,797)	$ (90,926)	$ (551,499)	$ (240,416)
Gain on common stock held by the NQDC	0	(4,980)	(1,753)	0
Net loss, diluted	$ (42,797)	$ (95,906)	$ (553,252)	$ (240,416)
Weighted-average common shares outstanding, basic	167,714	160,886	163,963	159,647
Common shares held by the NQDC	0	248	253	0
Weighted-average common shares outstanding, diluted	167,714	161,134	164,216	159,647
Net loss per common share, basic	$ (0.26)	$ (0.57)	$ (3.36)	$ (1.51)
Net loss per common share, diluted	$ (0.26)	$ (0.60)	$ (3.37)	$ (1.51)

Anti-Dilutive Common Stock Excl

Anti-Dilutive Common Stock Excluded From Computation of Diluted Net Loss Per Share (Detail) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential shares of common stock excluded from computation of earnings (loss) per share as they are anti-dilutive	21,792	22,008	21,523	22,123
Stock Option
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential shares of common stock excluded from computation of earnings (loss) per share as they are anti-dilutive	9,610	10,503	9,610	10,503
Common stock issuable under the 2017 Notes
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential shares of common stock excluded from computation of earnings (loss) per share as they are anti-dilutive	1,105	1,553	1,105	1,553
Common stock issuable under the 2018 and 2020 Notes
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential shares of common stock excluded from computation of earnings (loss) per share as they are anti-dilutive	7,966	7,966	7,966	7,966
Unvested restricted stock units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential shares of common stock excluded from computation of earnings (loss) per share as they are anti-dilutive	2,728	1,757	2,728	1,633
Common stock potentially issuable for ESPP purchases
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential shares of common stock excluded from computation of earnings (loss) per share as they are anti-dilutive	130	229	114	220
Common stock held by the NQDC
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential shares of common stock excluded from computation of earnings (loss) per share as they are anti-dilutive	253	0	0	248

Net Loss Per Common Share - Add

Net Loss Per Common Share - Additional Information (Detail) - $ / shares	Sep. 30, 2016	Sep. 30, 2015
Convertible Notes due 2018
Earnings Per Share [Line Items]
Debt instrument, interest rate, stated percentage, per annum	0.70%
Convertible Notes due 2020
Earnings Per Share [Line Items]
Debt instrument, interest rate, stated percentage, per annum	1.50%
The Notes
Earnings Per Share [Line Items]
Debt instrument, convertible, conversion price, per share	$ 94.15	$ 94.15

Amortized Cost Gross Unrealized

Amortized Cost Gross Unrealized Holding Gain or Loss and Fair Value of Available for Sale Security by Major Security Type (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 689,477	$ 622,207
Gross Unrealized Holding Gains	1,145	100
Gross Unrealized Holding Losses	(167)	(1,076)
Aggregate Fair Value	690,455	621,231
Certificates of Deposit
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,800	63,919
Gross Unrealized Holding Gains	0	1
Gross Unrealized Holding Losses	0	0
Aggregate Fair Value	2,800	63,920
Corporate Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	420,259	358,625
Gross Unrealized Holding Gains	873	20
Gross Unrealized Holding Losses	(165)	(732)
Aggregate Fair Value	420,967	357,913
Commercial Paper
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	16,692	12,733
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Aggregate Fair Value	16,692	12,733
U.S. Government Agency Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	249,674	186,882
Gross Unrealized Holding Gains	190	0
Gross Unrealized Holding Losses	(2)	(344)
Aggregate Fair Value	249,862	186,538
Greek Government-Issued Bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	52	48
Gross Unrealized Holding Gains	82	79
Gross Unrealized Holding Losses	0	0
Aggregate Fair Value	$ 134	$ 127

Investments - Additional Inform

Investments - Additional Information (Detail)	3 Months Ended	9 Months Ended	12 Months Ended
	Jun. 30, 2016USD ($)	Sep. 30, 2016USD ($)	Dec. 31, 2015USD ($)Investment
Investments Debt And Equity Securities [Abstract]
Number of investments in marketable equity securities | Investment			2
Marketable equity securities, realized loss	$ (2,000,000)
Fair value of marketable equity securities		$ 7,300,000	$ 18,100,000
Marketable equity securities, unrealized gain (loss)		4,300,000	$ 12,700,000
Other- than- temporary impairment		$ 0

Fair Values of Available-For-Sa

Fair Values of Available-For-Sale Securities by Contractual Maturity (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Investments Debt And Equity Securities [Abstract]
Maturing in one year or less	$ 327,499	$ 195,579
Maturing after one year through five years	362,956	425,652
Total	$ 690,455	$ 621,231

Intangible Assets (Detail)

Intangible Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Intangible assets:
Finite-lived intangible assets	$ 305,122	$ 129,572
Indefinite-lived intangible assets	332,199	607,548
Gross intangible assets:	637,321	737,120
Less: Accumulated amortization	(75,934)	(53,124)
Net carrying value	$ 561,387	$ 683,996	[1]
[1]	December 31, 2015 balances were derived from the audited Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015, filed with the Securities and Exchange Commission (the SEC) on February 29, 2016.

Intangible Assets - Additional

Intangible Assets - Additional Information (Detail) - USD ($)	3 Months Ended			9 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Goodwill And Intangible Assets [Line Items]
Impairment charge	$ 0		$ 0	$ 599,118,000	$ 0
Indefinite-lived intangible assets	$ 332,199,000			$ 332,199,000		$ 607,548,000
IPR&D of Kyndrisa and Other Exon
Goodwill And Intangible Assets [Line Items]
Impairment charge		$ 574,100,000
Indefinite-lived intangible assets		0
IPR&D of Reveglucosidase Alfa
Goodwill And Intangible Assets [Line Items]
Impairment charge		$ 25,000,000

Property Plant and Equipment (D

Property Plant and Equipment (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 1,058,030	$ 982,810
Less: Accumulated depreciation	(328,194)	(278,603)
Total property, plant and equipment, net	729,836	704,207	[1]
Building and Improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	505,894	442,100
Manufacturing and Laboratory Equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	229,818	145,313
Computer Hardware and Software
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	123,557	113,442
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	44,802	44,247
Furniture and Equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	26,359	22,817
Land Improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	4,881	4,881
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	45,727	45,727
Construction-in-Progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 76,992	$ 164,283
[1]	December 31, 2015 balances were derived from the audited Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015, filed with the Securities and Exchange Commission (the SEC) on February 29, 2016.

Property Plant and Equipment -

Property Plant and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Property Plant And Equipment [Abstract]
Depreciation expense	$ 23,200	$ 12,700	$ 56,100	$ 36,400
Depreciation capitalized into inventory	$ 4,400	$ 3,700	$ 13,402	$ 11,005

Schedule of Inventory (Detail)

Schedule of Inventory (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Inventory Disclosure [Abstract]
Raw materials	$ 46,951	$ 46,115
Work-in-process	189,596	150,289
Finished goods	110,873	75,279
Total inventory	$ 347,420	$ 271,683	[1]
[1]	December 31, 2015 balances were derived from the audited Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015, filed with the Securities and Exchange Commission (the SEC) on February 29, 2016.

Supplemental Balance Sheet In54

Supplemental Balance Sheet Information - Additional Information (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	[1]
Inventory [Line Items]
Inventory	$ 347,420	$ 271,683
Accounts Payable and Accrued Liabilities | Kyndrisa and Other Exon
Inventory [Line Items]
Accrued employee termination benefits	4,900
Shanbally, Ireland
Inventory [Line Items]
Escrow deposit to purchase land	8,400
Vimizim PreQual Inventory
Inventory [Line Items]
Inventory	29,800
Brineura Inventory
Inventory [Line Items]
Inventory	$ 31,300
[1]	December 31, 2015 balances were derived from the audited Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015, filed with the Securities and Exchange Commission (the SEC) on February 29, 2016.

Schedule of Other Assets (Detai

Schedule of Other Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Condensed Financial Information Of Parent Company Only Disclosure [Abstract]
Deposit for business acquisition	$ 0	$ 371,756
Deposits	19,748	8,606
Strategic investments	7,267	18,056
Long-term forward foreign currency exchange contract assets	750	3,533
Other	8,678	6,693
Total other assets	$ 36,443	$ 408,644	[1]
[1]	December 31, 2015 balances were derived from the audited Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015, filed with the Securities and Exchange Commission (the SEC) on February 29, 2016.

Schedule of Accounts Payable an

Schedule of Accounts Payable and Accrued Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Condensed Financial Information Of Parent Company Only Disclosure [Abstract]
Accounts payable and accrued operating expenses	$ 148,773	$ 179,294
Accrued compensation expense	85,219	95,345
Accrued rebates payable	34,184	32,553
Accrued royalties payable	14,183	10,412
Value added taxes payable	7,961	6,377
Accrued income taxes	0	59,572
Other	15,809	8,958
Total accounts payable and accrued liabilities	$ 306,129	$ 392,511	[1]
[1]	December 31, 2015 balances were derived from the audited Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015, filed with the Securities and Exchange Commission (the SEC) on February 29, 2016.

Summary of Convertible Debt (De

Summary of Convertible Debt (Detail) - USD ($) $ in Thousands		Sep. 30, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Convertible Notes, net of unamortized deferred offering costs		$ 22,460	$ 0	[1]
Convertible Notes, net of unamortized discount and deferred offering costs		653,178	662,286	[1]
Total convertible debt, net		675,638	662,286
Convertible Notes, fair value		1,019,523	1,147,301
Convertible Notes due 2017
Debt Instrument [Line Items]
Convertible Notes		22,506	31,430
Convertible debt, Unamortized deferred offering costs		(46)	(110)
Convertible Notes, net of unamortized deferred offering costs		22,460	31,320
Convertible Notes, fair value	[2]	101,789	162,016
Convertible Notes due 2018
Debt Instrument [Line Items]
Convertible Notes		374,980	374,980
Convertible debt, unamortized discount		(31,219)	(41,904)
Convertible debt, Unamortized deferred offering costs		(3,968)	(5,415)
Convertible Notes, net of unamortized discount and deferred offering costs		339,793	327,661
Convertible Notes, fair value	[2]	448,247	482,584
Convertible Notes due 2020
Debt Instrument [Line Items]
Convertible Notes		374,993	374,993
Convertible debt, unamortized discount		(56,364)	(65,478)
Convertible debt, Unamortized deferred offering costs		(5,244)	(6,210)
Convertible Notes, net of unamortized discount and deferred offering costs		313,385	303,305
Convertible Notes, fair value	[2]	$ 469,487	$ 502,701
[1]	December 31, 2015 balances were derived from the audited Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015, filed with the Securities and Exchange Commission (the SEC) on February 29, 2016.
[2]	The fair value of the Company’s fixed rate convertible debt is based on open market trades and is classified as Level 1 in the fair value hierarchy.

Summary of Interest Expense on

Summary of Interest Expense on Convertible Debt (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Schedule Of Interest Expenses [Line Items]
Total interest expense on convertible debt	$ 9,980	$ 9,447	$ 29,767	$ 28,911
Convertible Senior Notes
Schedule Of Interest Expenses [Line Items]
Coupon interest	2,466	2,283	7,491	7,667
Amortization of issuance costs	826	823	2,476	2,471
Accretion of debt discount	6,688	6,341	19,800	18,773
Total interest expense on convertible debt	$ 9,980	$ 9,447	$ 29,767	$ 28,911

Convertible Debt - Additional I

Convertible Debt - Additional Information (Detail) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016USD ($)shares	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)shares	Sep. 30, 2015USD ($)Agreementshares
Debt Conversion [Line Items]
Convertible cash premium paid to holder for agreeing to convert	$ 0	$ 0	$ 0	$ 163
Convertible Notes due 2017
Debt Conversion [Line Items]
Number of agreements | Agreement				3
Convertible Notes due 2017 | 2015 Induced Conversion
Debt Conversion [Line Items]
Convertible notes aggregate principal	$ 2,000		$ 8,900	$ 8,100
Notes converted, number of shares | shares	97,348		438,315	399,469
Convertible cash premium paid to holder for agreeing to convert				$ 200
Convertible Notes due 2017 | Convertible Senior Notes | 2015 Induced Conversion
Debt Conversion [Line Items]
Convertible cash premium paid to holder for agreeing to convert				$ 200

Summary of Designated Forward F

Summary of Designated Forward Foreign Currency Exchange Contracts Outstanding (Detail) - Foreign exchange contracts	9 Months Ended
	Sep. 30, 2016EUR (€)Derivative	Sep. 30, 2016CADDerivative	Sep. 30, 2016COPDerivative	Sep. 30, 2016GBP (£)Derivative
Maximum
Derivative [Line Items]
Maturity	Sep. 30, 2019
Derivatives Designated As Hedging Instruments
Derivative [Line Items]
Number of Contracts	374	374	374	374
Derivatives Designated As Hedging Instruments | Euros | Purchase
Derivative [Line Items]
Number of Contracts	84	84	84	84
Aggregate Notional Amount in Foreign Currency | €	€ 92,500,000
Derivatives Designated As Hedging Instruments | Euros | Sell
Derivative [Line Items]
Number of Contracts	280	280	280	280
Aggregate Notional Amount in Foreign Currency | €	€ 316,500,000
Derivatives Designated As Hedging Instruments | Euros | Minimum | Purchase
Derivative [Line Items]
Maturity	Oct. 31, 2016
Derivatives Designated As Hedging Instruments | Euros | Minimum | Sell
Derivative [Line Items]
Maturity	Oct. 31, 2016
Derivatives Designated As Hedging Instruments | Euros | Maximum | Purchase
Derivative [Line Items]
Maturity	Sep. 30, 2019
Derivatives Designated As Hedging Instruments | Euros | Maximum | Sell
Derivative [Line Items]
Maturity	Sep. 30, 2019
Derivatives Designated As Hedging Instruments | Canadian Dollars | Sell
Derivative [Line Items]
Number of Contracts	6	6	6	6
Aggregate Notional Amount in Foreign Currency | CAD		CAD 3,100,000
Derivatives Designated As Hedging Instruments | Canadian Dollars | Minimum | Sell
Derivative [Line Items]
Maturity	Oct. 31, 2016
Derivatives Designated As Hedging Instruments | Canadian Dollars | Maximum | Sell
Derivative [Line Items]
Maturity	Dec. 31, 2016
Derivatives Designated As Hedging Instruments | Colombian Pesos | Sell
Derivative [Line Items]
Number of Contracts	3	3	3	3
Aggregate Notional Amount in Foreign Currency | COP			COP 9,798,000,000
Derivatives Designated As Hedging Instruments | Colombian Pesos | Minimum | Sell
Derivative [Line Items]
Maturity	Oct. 31, 2016
Derivatives Designated As Hedging Instruments | Colombian Pesos | Maximum | Sell
Derivative [Line Items]
Maturity	Dec. 31, 2016
Derivatives Designated As Hedging Instruments | British Pounds | Sell
Derivative [Line Items]
Number of Contracts	1	1	1	1
Aggregate Notional Amount in Foreign Currency | £				£ 600,000
Maturity	Oct. 31, 2016

Summary of Non-Designated Forwa

Summary of Non-Designated Forward Foreign Currency Exchange Contracts Outstanding (Detail) - Foreign exchange contracts	9 Months Ended
	Sep. 30, 2016EUR (€)Derivative	Sep. 30, 2016GBP (£)Derivative
Maximum
Derivative [Line Items]
Maturity	Sep. 30, 2019
Not Designated as Hedging Instrument
Derivative [Line Items]
Number of Contracts	2	2
Not Designated as Hedging Instrument | Euros | Purchase
Derivative [Line Items]
Number of Contracts	1	1
Aggregate Notional Amount in Foreign Currency | €	€ 99,400,000
Maturity	Oct. 31, 2016
Not Designated as Hedging Instrument | British Pounds | Sell
Derivative [Line Items]
Number of Contracts	1	1
Aggregate Notional Amount in Foreign Currency | £		£ 6,900,000
Maturity	Oct. 31, 2016

Derivative Instruments and He62

Derivative Instruments and Hedging Strategies - Additional Information (Detail) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Derivative [Line Items]
Gain (Loss) from foreign currency exchange contracts in accumulated other comprehensive income	$ 1.2	$ 13.6
Foreign Currency Derivatives
Derivative [Line Items]
Amount reclassified from accumulated other comprehensive income to earnings as related to forecasted revenue and operating expense transactions	$ 0.5
Maximum length of time over which hedging its exposure to the reduction in value of forecasted foreign currency cash flows through foreign currency forward contracts	12 months
Foreign Currency Derivatives | Maximum
Derivative [Line Items]
Maturity period of foreign currency derivatives	Sep. 30, 2019

Derivative Instruments and He63

Derivative Instruments and Hedging Strategies (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Derivative [Line Items]
Derivative Asset, Fair Value	$ 5,560	$ 14,011
Derivative Liability, Fair Value	5,334	5,065
Derivatives Designated As Hedging Instruments
Derivative [Line Items]
Derivative Asset, Fair Value	5,535	14,011
Derivative Liability, Fair Value	5,269	5,043
Derivatives Designated As Hedging Instruments | Forward Foreign Currency Exchange Contracts | Other Current Assets
Derivative [Line Items]
Derivative Asset, Fair Value	4,785	10,478
Derivatives Designated As Hedging Instruments | Forward Foreign Currency Exchange Contracts | Other Assets
Derivative [Line Items]
Derivative Asset, Fair Value	750	3,533
Derivatives Designated As Hedging Instruments | Forward Foreign Currency Exchange Contracts | Accounts Payable and Accrued Liabilities
Derivative [Line Items]
Derivative Liability, Fair Value	3,290	1,986
Derivatives Designated As Hedging Instruments | Forward Foreign Currency Exchange Contracts | Other Long-Term Liabilities
Derivative [Line Items]
Derivative Liability, Fair Value	1,979	3,057
Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative Asset, Fair Value	25	0
Derivative Liability, Fair Value	65	22
Not Designated as Hedging Instrument | Forward Foreign Currency Exchange Contracts | Other Current Assets
Derivative [Line Items]
Derivative Asset, Fair Value	25	0
Not Designated as Hedging Instrument | Forward Foreign Currency Exchange Contracts | Other Assets
Derivative [Line Items]
Derivative Asset, Fair Value	0
Not Designated as Hedging Instrument | Forward Foreign Currency Exchange Contracts | Accounts Payable and Accrued Liabilities
Derivative [Line Items]
Derivative Liability, Fair Value	65	$ 22
Not Designated as Hedging Instrument | Forward Foreign Currency Exchange Contracts | Other Long-Term Liabilities
Derivative [Line Items]
Derivative Liability, Fair Value	$ 0

Effect of Derivative Instrument

Effect of Derivative Instruments (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended		12 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Net gain (loss) recognized in Other Comprehensive Income (OCI)				$ 1,200		$ 13,600
Forward Foreign Currency Exchange Contracts | Derivatives Designated As Hedging Instruments
Derivative Instruments, Gain (Loss) [Line Items]
Net gain (loss) recognized in Other Comprehensive Income (OCI)	[1]	$ (1,984)	$ 3,126	(5,857)	$ 14,191
Net gain reclassified from accumulated OCI into earnings	[2]	1,486	5,187	4,616	15,084
Net gain (loss) recognized in net loss	[3]	9	(264)	5,276	(404)
Forward Foreign Currency Exchange Contracts | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Net gain (loss) recognized in net loss	[4]	$ 826	$ (514)	$ (2,446)	$ 6,052
[1]	Net change in the fair value of the effective portion classified as OCI.
[2]	Effective portion classified as Net Product Revenues and SG&A expense.
[3]	Ineffective portion and amount excluded from effectiveness testing classified as SG&A expense.
[4]	Classified as SG&A expense.

Fair Value of Financial Assets

Fair Value of Financial Assets and Liabilities (Detail) - USD ($) $ in Thousands		Sep. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Available-for-sale securities		$ 690,455	$ 621,231
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Cash and cash equivalents		707,349	397,040
Fair value of Available-for-sale securities		690,455	621,231
Fair value of other current assets		9,171	18,266
Fair value of other non-current assets		16,579	27,951
Fair value of financial assets, Total		1,423,554	1,064,488
Fair value of other current liabilities		56,418	56,545
Fair value of other non-current liabilities		152,579	66,423
Fair value of financial liabilities, Total		208,997	122,968
Fair Value, Measurements, Recurring | Overnight Deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Cash and cash equivalents		246,568	290,731
Fair Value, Measurements, Recurring | Money Market Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Cash and cash equivalents		460,781	106,309
Fair Value, Measurements, Recurring | Nonqualified Deferred Compensation Plan Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current liabilities		4,317	1,591
Fair value of other non-current liabilities		27,956	30,703
Fair Value, Measurements, Recurring | Forward Foreign Currency Exchange Contract, Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current liabilities	[1]	3,355	2,008
Fair value of other non-current liabilities	[1]	1,979	3,057
Fair Value, Measurements, Recurring | Contingent Acquisition Consideration Payable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current liabilities		48,746	52,946
Fair value of other non-current liabilities		122,644	32,663
Fair Value, Measurements, Recurring | Certificates of Deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Available-for-sale securities, current		2,800	56,951
Fair value of Available-for-sale securities, non-current			6,969
Fair Value, Measurements, Recurring | Corporate Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Available-for-sale securities, current		139,073	42,673
Fair value of Available-for-sale securities, non-current		281,894	315,240
Fair Value, Measurements, Recurring | Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Available-for-sale securities, current		16,692	12,733
Fair Value, Measurements, Recurring | U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Available-for-sale securities, current		168,934	83,222
Fair value of Available-for-sale securities, non-current		80,928	103,316
Fair Value, Measurements, Recurring | Greek Government-Issued Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Available-for-sale securities, non-current		134	127
Fair Value, Measurements, Recurring | Nonqualified Deferred Compensation Plan Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current assets		309	440
Fair value of other non-current assets		8,562	6,362
Fair Value, Measurements, Recurring | Forward Foreign Current Exchange Contract Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current assets	[1]	4,810	10,478
Fair value of other non-current assets	[1]	750	3,533
Fair Value, Measurements, Recurring | Restrictive Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current assets	[2]	4,052	7,348
Fair Value, Measurements, Recurring | Strategic Investment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other non-current assets	[3]	7,267	18,056
Fair Value, Measurements, Recurring | Quoted Price In Active Markets For Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Cash and cash equivalents		246,568	290,731
Fair value of Available-for-sale securities		0	0
Fair value of other current assets		0	0
Fair value of other non-current assets		7,267	18,056
Fair value of financial assets, Total		253,835	308,787
Fair value of other current liabilities		4,008	1,151
Fair value of other non-current liabilities		19,394	24,341
Fair value of financial liabilities, Total		23,402	25,492
Fair Value, Measurements, Recurring | Quoted Price In Active Markets For Identical Assets (Level 1) | Overnight Deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Cash and cash equivalents		246,568	290,731
Fair Value, Measurements, Recurring | Quoted Price In Active Markets For Identical Assets (Level 1) | Money Market Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Cash and cash equivalents		0	0
Fair Value, Measurements, Recurring | Quoted Price In Active Markets For Identical Assets (Level 1) | Nonqualified Deferred Compensation Plan Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current liabilities		4,008	1,151
Fair value of other non-current liabilities		19,394	24,341
Fair Value, Measurements, Recurring | Quoted Price In Active Markets For Identical Assets (Level 1) | Forward Foreign Currency Exchange Contract, Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current liabilities	[1]	0	0
Fair value of other non-current liabilities	[1]	0	0
Fair Value, Measurements, Recurring | Quoted Price In Active Markets For Identical Assets (Level 1) | Contingent Acquisition Consideration Payable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current liabilities		0	0
Fair value of other non-current liabilities		0	0
Fair Value, Measurements, Recurring | Quoted Price In Active Markets For Identical Assets (Level 1) | Certificates of Deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Available-for-sale securities, current		0	0
Fair value of Available-for-sale securities, non-current			0
Fair Value, Measurements, Recurring | Quoted Price In Active Markets For Identical Assets (Level 1) | Corporate Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Available-for-sale securities, current		0	0
Fair value of Available-for-sale securities, non-current		0	0
Fair Value, Measurements, Recurring | Quoted Price In Active Markets For Identical Assets (Level 1) | Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Available-for-sale securities, current		0	0
Fair Value, Measurements, Recurring | Quoted Price In Active Markets For Identical Assets (Level 1) | U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Available-for-sale securities, current		0	0
Fair value of Available-for-sale securities, non-current		0	0
Fair Value, Measurements, Recurring | Quoted Price In Active Markets For Identical Assets (Level 1) | Greek Government-Issued Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Available-for-sale securities, non-current		0	0
Fair Value, Measurements, Recurring | Quoted Price In Active Markets For Identical Assets (Level 1) | Nonqualified Deferred Compensation Plan Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current assets		0	0
Fair value of other non-current assets		0	0
Fair Value, Measurements, Recurring | Quoted Price In Active Markets For Identical Assets (Level 1) | Forward Foreign Current Exchange Contract Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current assets	[1]	0	0
Fair value of other non-current assets	[1]	0	0
Fair Value, Measurements, Recurring | Quoted Price In Active Markets For Identical Assets (Level 1) | Restrictive Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current assets	[2]	0	0
Fair Value, Measurements, Recurring | Quoted Price In Active Markets For Identical Assets (Level 1) | Strategic Investment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other non-current assets	[3]	7,267	18,056
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Cash and cash equivalents		460,781	106,309
Fair value of Available-for-sale securities		690,455	621,231
Fair value of other current assets		9,171	18,266
Fair value of other non-current assets		9,312	9,895
Fair value of financial assets, Total		1,169,719	755,701
Fair value of other current liabilities		3,664	2,448
Fair value of other non-current liabilities		10,541	9,419
Fair value of financial liabilities, Total		14,205	11,867
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Overnight Deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Cash and cash equivalents		0	0
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Money Market Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Cash and cash equivalents		460,781	106,309
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Nonqualified Deferred Compensation Plan Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current liabilities		309	440
Fair value of other non-current liabilities		8,562	6,362
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Forward Foreign Currency Exchange Contract, Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current liabilities	[1]	3,355	2,008
Fair value of other non-current liabilities	[1]	1,979	3,057
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Contingent Acquisition Consideration Payable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current liabilities		0	0
Fair value of other non-current liabilities		0	0
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Certificates of Deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Available-for-sale securities, current		2,800	56,951
Fair value of Available-for-sale securities, non-current			6,969
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Corporate Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Available-for-sale securities, current		139,073	42,673
Fair value of Available-for-sale securities, non-current		281,894	315,240
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Available-for-sale securities, current		16,692	12,733
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Available-for-sale securities, current		168,934	83,222
Fair value of Available-for-sale securities, non-current		80,928	103,316
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Greek Government-Issued Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Available-for-sale securities, non-current		134	127
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Nonqualified Deferred Compensation Plan Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current assets		309	440
Fair value of other non-current assets		8,562	6,362
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Forward Foreign Current Exchange Contract Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current assets	[1]	4,810	10,478
Fair value of other non-current assets	[1]	750	3,533
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Restrictive Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current assets	[2]	4,052	7,348
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Strategic Investment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other non-current assets	[3]	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Cash and cash equivalents		0	0
Fair value of Available-for-sale securities		0	0
Fair value of other current assets		0	0
Fair value of other non-current assets		0	0
Fair value of financial assets, Total		0	0
Fair value of other current liabilities		48,746	52,946
Fair value of other non-current liabilities		122,644	32,663
Fair value of financial liabilities, Total		171,390	85,609
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Overnight Deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Cash and cash equivalents		0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Money Market Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Cash and cash equivalents		0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Nonqualified Deferred Compensation Plan Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current liabilities		0	0
Fair value of other non-current liabilities		0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Forward Foreign Currency Exchange Contract, Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current liabilities	[1]	0	0
Fair value of other non-current liabilities	[1]	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Contingent Acquisition Consideration Payable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current liabilities		48,746	52,946
Fair value of other non-current liabilities		122,644	32,663
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Certificates of Deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Available-for-sale securities, current		0	0
Fair value of Available-for-sale securities, non-current			0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Corporate Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Available-for-sale securities, current		0	0
Fair value of Available-for-sale securities, non-current		0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Available-for-sale securities, current		0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Available-for-sale securities, current		0	0
Fair value of Available-for-sale securities, non-current		0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Greek Government-Issued Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Available-for-sale securities, non-current		0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Nonqualified Deferred Compensation Plan Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current assets		0	0
Fair value of other non-current assets		0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Forward Foreign Current Exchange Contract Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current assets	[1]	0	0
Fair value of other non-current assets	[1]	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Restrictive Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current assets	[2]	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Strategic Investment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other non-current assets	[3]	$ 0	$ 0
[1]	See Note 12 to these Condensed Consolidated Financial Statements for further information regarding the derivative instruments.
[2]	The restricted investments at September 30, 2016 and December 31, 2015 secure the Company’s irrevocable standby letter of credit obtained in connection with certain commercial agreements.
[3]	The Company has investments in marketable equity securities measured using quoted prices in an active market that are considered strategic investments. See Note 7 to these Condensed Consolidated Financial Statements for additional discussion regarding the Company’s strategic investments.

Liabilities Measured at Fair Va

Liabilities Measured at Fair Value Using Level 3 Inputs (Detail) - Contingent Payment $ in Thousands	9 Months Ended
	Sep. 30, 2016USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Contingent acquisition consideration payable, Beginning balance	$ 85,609
Addition of contingent acquisition consideration payable related to the purchase of the Merck PKU Business	138,974
Changes in the fair value of contingent acquisition consideration payable for continuing development programs	7,032
Foreign exchange remeasurement of Euro denominated contingent acquisition consideration payable	3,761
Contingent acquisition consideration payable, Ending balance	171,390
Kyndrisa
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Reduction of fair value related to termination of development program	(43,652)
Reveglucosidase Alfa
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Reduction of fair value related to termination of development program	$ (20,334)

Asset Retirement Obligation Lia

Asset Retirement Obligation Liability and Corresponding Capital Asset (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2016USD ($)
Asset Retirement Obligation Disclosure [Abstract]
Asset retirement obligation, Beginning balance	$ 4,704
Accretion expense	79
Reversals	(250)
Asset retirement obligations, Ending balance	$ 4,533

Assumptions Used to Estimate Pe

Assumptions Used to Estimate Per Share Fair Value of Stock Options Granted (Detail) - Stock Option	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility, minimum	38.00%	41.00%	36.00%	39.00%
Expected volatility, maximum	40.00%	44.00%	44.00%	45.00%
Dividend yield	0.00%	0.00%	0.00%	0.00%
Risk-free interest rate, minimum	1.10%	1.90%	1.10%	1.50%
Risk-free interest rate, maximum	1.40%	2.20%	2.10%	2.20%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life	5 years	6 years 10 months 24 days	5 years	6 years 4 months 24 days
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life	6 years 8 months 12 days	8 years	8 years 1 month 6 days	8 years

Stock Based Compensation - Addi

Stock Based Compensation - Additional Information (Detail) $ / shares in Units, $ in Thousands	Mar. 15, 2016shares	Mar. 03, 2015shares	Sep. 30, 2016USD ($)shares	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)$ / sharesshares	Sep. 30, 2015USD ($)$ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares, granted					783,580
Weighted-average fair value per share granted | $ / shares					$ 41.15
Recognized compensation costs | $			$ 32,902	$ 28,758	$ 97,220	$ 80,959
Stock-based compensation expense capitalized to inventory | $					$ 9,000	$ 8,300
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares, granted					1,223,654
Weighted-average fair value per RSU granted | $ / shares					$ 83.81
Restricted Stock With Performance and Market Based Vesting Conditions
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average fair value per RSU granted | $ / shares					$ 34.66
Granted restricted stock units			860,000		860,000
Total shareholder return, percentage of multiplier range					124.00%
Restricted stock units, earned			799,800		799,800
2016 Base Restricted Stock Unit Awards with Performance Conditions
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average fair value per RSU granted | $ / shares					$ 83.43
Granted restricted stock units	130,310
Award vesting service period	3 years
Recognized compensation costs | $			$ 1,000		$ 2,100
2016 Base Restricted Stock Unit Awards with Performance Conditions | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Revenue multiplier	0.80
2016 Base Restricted Stock Unit Awards with Performance Conditions | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Revenue multiplier	1.20
2015 Base Restricted Stock Unit Awards with Performance Conditions
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average fair value per RSU granted | $ / shares						$ 108.36
Granted restricted stock units		58,300
Revenue multiplier		1.11
Award vesting service period		3 years
Recognized compensation costs | $			$ 600	$ 500	$ 1,800	$ 1,300
Number of units that could vest if performance condition is achieved and a revenue multiplier is applied		64,713

Compensation Expense (Detail)

Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 32,902	$ 28,758	$ 97,220	$ 80,959
Cost of Sales
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	2,092	1,386	5,943	4,484
Research and Development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	14,165	12,578	42,929	34,972
Selling, General and Administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 16,645	$ 14,794	$ 48,348	$ 41,503

Amounts Reclassified out of Acc

Amounts Reclassified out of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Net product revenues	$ 278,262	$ 207,767	$ 812,195	$ 658,102
SG&A	118,758	94,044	333,635	288,364
Other income (expense)	1,723	(281)	504	(9,105)
Provision for (benefit from) income taxes	(24,016)	483	(187,385)	(7,273)
NET LOSS	(42,797)	(90,926)	(551,499)	(240,416)
Reclassified out of Accumulated Other Comprehensive Income
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Provision for (benefit from) income taxes	2	5	(735)	1,098
NET LOSS	1,491	5,196	7,625	17,022
Reclassified out of Accumulated Other Comprehensive Income | Gains (losses) on Cash Flow Hedges | Forward Foreign Currency Exchange Contracts
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Net product revenues	1,436	4,411	4,036	13,660
SG&A	50	776	4,874	1,424
Reclassified out of Accumulated Other Comprehensive Income | Gain (loss) on Sale of Available-For-Sale Securities
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Other income (expense)	$ 7	$ 14	$ (2,020)	$ 3,036

Summary of Changes in Accumulat

Summary of Changes in Accumulated Balances of AOCI Including Current Period Other Comprehensive Income and Reclassifications (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	[1]			$ 2,400,847
Other comprehensive income (loss) before reclassifications		$ (247)	$ (5,032)	(14,333)	$ 15,059
Less net gain (loss) reclassified from AOCI		1,493	5,201	6,890	18,120
Tax effect		(630)	2,956	2,348	779
Net current-period other comprehensive income (loss)		(2,370)	(7,277)	(18,875)	(2,282)
Ending Balance		2,645,808		2,645,808
Unrealized Gains (Losses) on Cash Flow Hedges
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		2,305	17,074	13,602	15,906
Other comprehensive income (loss) before reclassifications		(1,984)	3,126	(5,857)	14,191
Less net gain (loss) reclassified from AOCI		1,486	5,187	8,910	15,084
Tax effect		0	0	0	0
Net current-period other comprehensive income (loss)		(3,470)	(2,061)	(14,767)	(893)
Ending Balance		(1,165)	15,013	(1,165)	15,013
Unrealized Gains (Losses) on Available-for-Sale Securities
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		2,231	15,336	7,441	11,511
Other comprehensive income (loss) before reclassifications		1,738	(8,159)	(8,477)	865
Less net gain (loss) reclassified from AOCI		7	14	(2,020)	3,036
Tax effect		(630)	2,956	2,348	779
Net current-period other comprehensive income (loss)		1,101	(5,217)	(4,109)	(1,392)
Ending Balance		3,332	10,119	3,332	10,119
Foreign Currency Items
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		(8)	51	(10)	49
Other comprehensive income (loss) before reclassifications		(1)	1	1	3
Less net gain (loss) reclassified from AOCI		0	0	0	0
Tax effect		0	0	0	0
Net current-period other comprehensive income (loss)		(1)	1	1	3
Ending Balance		(9)	52	(9)	52
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		4,528	32,461	21,033	27,466
Ending Balance		$ 2,158	$ 25,184	$ 2,158	$ 25,184
[1]	December 31, 2015 balances were derived from the audited Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015, filed with the Securities and Exchange Commission (the SEC) on February 29, 2016.

Consolidated Net Product Revenu

Consolidated Net Product Revenue Concentrations Based on Patient Location (Detail) - Net Product Revenue	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Geographic Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	91.00%	90.00%	93.00%	91.00%
Geographic Concentration Risk | United States
Concentration Risk [Line Items]
Concentration risk, percentage	38.00%	44.00%	38.00%	38.00%
Geographic Concentration Risk | Europe
Concentration Risk [Line Items]
Concentration risk, percentage	23.00%	21.00%	23.00%	19.00%
Geographic Concentration Risk | Latin America
Concentration Risk [Line Items]
Concentration risk, percentage	14.00%	12.00%	13.00%	19.00%
Geographic Concentration Risk | Rest of World
Concentration Risk [Line Items]
Concentration risk, percentage	16.00%	13.00%	19.00%	15.00%
Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	48.00%	43.00%	48.00%	43.00%
Customer Concentration Risk | Genzyme | Product Four
Concentration Risk [Line Items]
Concentration risk, percentage	9.00%	10.00%	7.00%	9.00%
Credit Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	100.00%	100.00%	100.00%	100.00%

Consolidated Net Product Reve74

Consolidated Net Product Revenue Concentrations Attributed to Largest Customers (Detail) - Customer Concentration Risk - Net Product Revenue	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Concentration Risk [Line Items]
Concentration risk, percentage	48.00%	43.00%	48.00%	43.00%
Customer A
Concentration Risk [Line Items]
Concentration risk, percentage	19.00%	15.00%	19.00%	14.00%
Customer B
Concentration Risk [Line Items]
Concentration risk, percentage	13.00%	9.00%	13.00%	11.00%
Customer C
Concentration Risk [Line Items]
Concentration risk, percentage	6.00%	6.00%	6.00%	13.00%
Customer D
Concentration Risk [Line Items]
Concentration risk, percentage	10.00%	13.00%	10.00%	5.00%

Revenue and Credit Concentrat75

Revenue and Credit Concentrations - Additional Information (Detail) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016USD ($)	Sep. 30, 2015	Sep. 30, 2016USD ($)Customer	Sep. 30, 2015	Dec. 31, 2015USD ($)Customer
Concentration Risk [Line Items]
Accounts receivable, net	$ 215,894		$ 215,894		$ 164,959	[1]
Southern European Countries
Concentration Risk [Line Items]
Total amount past due	26,400		26,400
Southern European Countries | Greater than 90 days
Concentration Risk [Line Items]
Total amount past due	2,600		$ 2,600
Largest Customers
Concentration Risk [Line Items]
Number of customers accounted for largest balance in accounts receivable | Customer			2		2
Accounts receivable, net	$ 22,600		$ 22,600		$ 36,100
Credit Concentration Risk | Accounts Receivable | Larger Customer One
Concentration Risk [Line Items]
Concentration risk, percentage			22.00%		37.00%
Credit Concentration Risk | Accounts Receivable | Larger Customer Two
Concentration Risk [Line Items]
Concentration risk, percentage			19.00%		18.00%
Credit Concentration Risk | Net Product Revenue
Concentration Risk [Line Items]
Concentration risk, percentage	100.00%	100.00%	100.00%	100.00%
Geographic Concentration Risk | Accounts Receivable | Southern European Countries
Concentration Risk [Line Items]
Concentration risk, percentage	12.00%		12.00%
Geographic Concentration Risk | Net Product Revenue
Concentration Risk [Line Items]
Concentration risk, percentage	91.00%	90.00%	93.00%	91.00%
Geographic Concentration Risk | Net Product Revenue | Southern European Countries
Concentration Risk [Line Items]
Concentration risk, percentage	8.00%		7.00%
[1]	December 31, 2015 balances were derived from the audited Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015, filed with the Securities and Exchange Commission (the SEC) on February 29, 2016.

Segment Information - Additiona

Segment Information - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2016Segment
Segment Reporting [Abstract]
Number of operating business segment	1

Segment Information by Product

Segment Information by Product Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Revenue from External Customer [Line Items]
Net product revenues	$ 278,262	$ 207,767	$ 812,195	$ 658,102
Vimizim
Revenue from External Customer [Line Items]
Net product revenues	80,903	65,106	260,310	169,608
Naglazyme
Revenue from External Customer [Line Items]
Net product revenues	77,728	54,131	221,575	243,386
Kuvan
Revenue from External Customer [Line Items]
Net product revenues	90,899	64,219	257,806	174,501
Aldurazyme
Revenue from External Customer [Line Items]
Net product revenues	23,751	20,509	58,819	58,991
Firdapse
Revenue from External Customer [Line Items]
Net product revenues	$ 4,981	$ 3,802	$ 13,685	$ 11,616

Summary of Total Revenues from

Summary of Total Revenues from External Customers and Collaborative Partners by Geographic Region (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Revenue from External Customer [Line Items]
Total revenues	$ 279,896	$ 208,904	$ 816,763	$ 661,959
United States
Revenue from External Customer [Line Items]
Total revenues	130,356	112,254	365,674	310,209
Europe
Revenue from External Customer [Line Items]
Total revenues	62,821	42,816	187,328	124,252
Latin America
Revenue from External Customer [Line Items]
Total revenues	38,789	25,588	106,803	127,147
Rest of World
Revenue from External Customer [Line Items]
Total revenues	$ 47,930	$ 28,246	$ 156,958	$ 100,351

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Thousands, € in Millions	9 Months Ended
	Sep. 30, 2016USD ($)$ / €	Sep. 30, 2016EUR (€)	Dec. 31, 2015USD ($)	[1]
Commitments and Contingencies [Line Items]
Contingent payments upon achievement of certain development and regulatory activities and commercial sales and licensing milestones	$ 754,400
Contingent consideration payable	171,400
Short-term contingent acquisition consideration payable	48,746		$ 52,946
Purchase commitment for the next five years	50,900
Merck PKU Business
Commitments and Contingencies [Line Items]
Contingent payments upon achievement of certain development and regulatory activities and commercial sales and licensing milestones	$ 207,600	€ 185
Currency exchange translation rate | $ / €	1.12
Completed Programs
Commitments and Contingencies [Line Items]
Contingent payments upon achievement of certain development and regulatory activities and commercial sales and licensing milestones	$ 58,200
[1]	December 31, 2015 balances were derived from the audited Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015, filed with the Securities and Exchange Commission (the SEC) on February 29, 2016.