BioMarin Pharmaceutical (BMRN) 10-Q 29 Apr 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	Apr. 15, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Trading Symbol	BMRN
Entity Registrant Name	BIOMARIN PHARMACEUTICAL INC
Entity Central Index Key	0001048477
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		179,071,353

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands		Mar. 31, 2019	Dec. 31, 2018	[1]
Current assets:
Cash and cash equivalents		$ 364,369	$ 493,982
Short-term investments	[2]	530,485	590,326
Accounts receivable, net		393,429	342,633
Inventory		534,696	530,871
Other current assets		93,876	98,403
Total current assets		1,916,855	2,056,215
Noncurrent assets:
Long-term investments	[3]	320,000	235,864
Property, plant and equipment, net		951,890	948,682
Intangible assets, net		485,981	491,808
Goodwill		197,039	197,039
Deferred tax assets		467,333	460,952
Other assets		96,300	36,568
Total assets		4,435,398	4,427,128
Current liabilities:
Accounts payable and accrued liabilities		412,830	437,290
Short-term contingent consideration		88,156	85,951
Total current liabilities		500,986	523,241
Noncurrent liabilities:
Long-term convertible debt, net		834,766	830,417
Long-term contingent consideration		48,461	46,883
Other long-term liabilities		114,558	58,647
Total liabilities		1,498,771	1,459,188
Stockholders’ equity:
Common stock, $0.001 par value: 500,000,000 shares authorized; 179,033,104 and 178,252,954 shares issued and outstanding, respectively.		179	178
Additional paid-in capital		4,682,900	4,669,926
Company common stock held by Nonqualified Deferred Compensation Plan (the NQDC)		(12,912)	(13,301)
Accumulated other comprehensive income		19,794	5,271
Accumulated deficit		(1,753,334)	(1,694,134)
Total stockholders’ equity		2,936,627	2,967,940
Total liabilities and stockholders’ equity		$ 4,435,398	$ 4,427,128
[1]	December 31, 2018 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, 2018, filed with the SEC on February 28, 2019.
[2]	The Company’s short-term marketable securities mature in one year or less.
[3]	The Company’s long-term marketable securities mature between one and five years.

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Mar. 31, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	179,033,104	178,252,954
Common stock, shares outstanding	179,033,104	178,252,954

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
REVENUES:
Total revenues	$ 400,745	$ 373,447
OPERATING EXPENSES:
Cost of sales	89,182	82,333
Research and development	183,591	183,948
Selling, general and administrative	162,158	138,336
Intangible asset amortization and contingent consideration	19,765	13,202
Total operating expenses	454,696	417,819
LOSS FROM OPERATIONS	(53,951)	(44,372)
Equity in the income (loss) of BioMarin/Genzyme LLC	(185)	68
Interest income	6,298	5,234
Interest expense	(6,727)	(11,562)
Other income (expense), net	1,608	(172)
LOSS BEFORE INCOME TAXES	(52,957)	(50,804)
Provision for (benefit from) income taxes	3,516	(6,655)
NET LOSS	$ (56,473)	$ (44,149)
NET LOSS PER SHARE, BASIC	$ (0.32)	$ (0.25)
NET LOSS PER SHARE, DILUTED	$ (0.32)	$ (0.26)
Weighted average common shares outstanding, basic	178,271	175,932
Weighted average common shares outstanding, diluted	178,271	176,150
COMPREHENSIVE LOSS	$ (41,950)	$ (49,147)
Net Product Revenues
REVENUES:
Total revenues	394,483	369,099
Royalty and Other Revenues
REVENUES:
Total revenues	$ 6,262	$ 4,348

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands		Total		Common Stock		Additional Paid-in Capital		Company Stock Held By NQDC	Accumulated Other Comprehensive Income (Loss)		Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2017	[1]			175,844
Issuances under equity incentive plans (in share)				809
Ending balance (in shares) at Mar. 31, 2018				176,653
Beginning Balance at Dec. 31, 2017		$ 2,808,663		$ 176	[1]	$ 4,483,220	[1]	$ (14,224)	$ (22,961)	[1]	$ (1,637,548)	[1]
Common stock:
Issuances under equity incentive plans, net of tax				1		(9,766)
Ending Balance at Mar. 31, 2018		2,807,003		$ 177		4,510,451	[1]	(14,017)	(28,545)		(1,661,063)
Additional paid-in capital:
Stock-based compensation						36,997
Company common stock held by the NQDC:
Common stock held by the NQDC								207
Accumulated other comprehensive income (loss):
Other comprehensive income (loss)									(4,998)
Accumulated Deficit:
Net loss		(44,149)									(44,149)
Impact of changes in accounting principle									(586)		20,634
Beginning balance (in shares) at Dec. 31, 2018	[1]			178,253
Issuances under equity incentive plans (in share)				780
Ending balance (in shares) at Mar. 31, 2019				179,033
Beginning Balance at Dec. 31, 2018		2,967,940	[2]	$ 178	[1]	4,669,926	[1]	(13,301)	5,271	[1]	(1,694,134)	[1]
Common stock:
Issuances under equity incentive plans, net of tax				1		(28,732)
Ending Balance at Mar. 31, 2019		2,936,627		$ 179		4,682,900	[1]	(12,912)	19,794		(1,753,334)
Additional paid-in capital:
Stock-based compensation						$ 41,706
Company common stock held by the NQDC:
Common stock held by the NQDC								$ 389
Accumulated other comprehensive income (loss):
Other comprehensive income (loss)									$ 14,523
Accumulated Deficit:
Net loss		$ (56,473)									(56,473)
Impact of changes in accounting principle											$ (2,727)
[1]	The beginning balances were derived from the audited Consolidated Financial Statements included in Company’s Annual Report on Form 10-K for the year ended December 31, 2018 and 2017, respectively, filed with the SEC on February 28, 2019 and February 26, 2018, respectively
[2]	December 31, 2018 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, 2018, filed with the SEC on February 28, 2019.

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019		Mar. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (56,473)		$ (44,149)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	22,427		23,633
Non-cash interest expense	4,409		8,601
Accretion of discount on investments	(891)		761
Stock-based compensation	42,761		36,608
Deferred income taxes	(704)		(13,988)
Unrealized foreign exchange (gain) loss	(419)		5,616
Non-cash changes in the fair value of contingent consideration	12,260		5,631
Other	(19)		662
Changes in operating assets and liabilities:
Accounts receivable, net	(51,690)		(26,257)
Inventory	1,735		10,843
Other current assets	10,112		2,924
Other assets	2,220		(1,099)
Accounts payable and accrued liabilities	(42,070)		(51,887)
Other long-term liabilities	1,474		(408)
Net cash used in operating activities	(54,868)		(42,509)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property, plant and equipment	(28,756)		(30,164)
Maturities and sales of investments	219,894		104,462
Purchases of available-for-sale securities	(239,843)		(145,933)
Other	(1,774)		(99)
Net cash used in investing activities	(50,479)		(71,734)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from exercises of awards under equity incentive plans	5,798		13,134
Taxes paid related to net share settlement of equity awards	(30,105)		(22,899)
Other	(674)		0
Net cash used in financing activities	(24,981)		(9,765)
Effect of exchange rate changes on cash	715		(40)
NET DECREASE IN CASH AND CASH EQUIVALENTS	(129,613)		(124,048)
Cash and cash equivalents:
Beginning of period	493,982	[1]	598,028
End of period	364,369		473,980
SUPPLEMENTAL CASH FLOW DISCLOSURES:
Cash paid for income taxes	906		11,731
Cash paid for interest	1,483		1,528
SUPPLEMENTAL CASH FLOW DISCLOSURES FOR NON CASH INVESTING AND FINANCING ACTIVITIES:
Decrease in accounts payable and accrued liabilities related to fixed assets	$ (3,502)		$ (11,367)
[1]	December 31, 2018 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, 2018, filed with the SEC on February 28, 2019.

NATURE OF OPERATIONS

NATURE OF OPERATIONS	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
NATURE OF OPERATIONS	(1) NATURE OF OPERATIONS BioMarin Pharmaceutical Inc. (the Company) is a global biotechnology company that develops and commercializes innovative therapies for people with serious and life-threatening rare 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 portfolio consists of several commercial therapies and multiple clinical and pre-clinical product candidates. The Company expects to continue to finance future cash needs that exceed its operating activities primarily through its current cash, cash equivalents and investments and through proceeds from debt or equity offerings, commercial borrowing, or through collaborative agreements with corporate partners. If the Company elects to increase its spending on development programs significantly above current long-term plans or enters into potential licenses and other acquisitions of complementary technologies, products or companies, the Company may need additional capital.

BASIS OF PRESENTATION

BASIS OF PRESENTATION	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
BASIS OF PRESENTATION	(2) BASIS OF PRESENTATION The accompanying Condensed Consolidated Financial Statements have been prepared pursuant to United States (U.S.) generally accepted accounting principles (U.S. GAAP) and 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 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, 2018 included in the Company’s Annual Report on Form 10-K. The results of operations for the three months ended March 31, 2019 are not necessarily indicative of the results that may be expected for the fiscal year ending December 31, 2019 or any other period. On January 1, 2019, the Company adopted Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) Topic 842, Leases Leases As a result of the cumulative impact of adopting ASC Topic 842, the Company recorded lease ROU assets of $55.9 million and lease liabilities of $59.0 million as of January 1, 2019, primarily related to real estate and equipment, based on the present value of future lease payments on the date of adoption. The difference between the ROU assets and lease liabilities was recorded as an adjustment to Accumulated Deficit. Refer to Note 11 for additional disclosures required by ASC Topic 842. On January 1, 2019, the Company adopted Accounting Standards Update No. 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities (ASU 2017-12), using the modified retrospective method U.S. GAAP 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. 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.

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	(3) SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Except as detailed below, there have been no material changes to the Company’s significant accounting policies during the three months ended March 31, 2019, as compared to the significant accounting policies disclosed in Note 3 – Significant Accounting Policies Leases The Company determines if an arrangement is a lease at inception. For leases where the Company is the lessee, ROU assets represent the Company’s right to use the underlying asset for the term of the lease and the lease liabilities represent an obligation to make lease payments arising from the lease. ROU assets and lease liabilities are recognized at the lease commencement date based on the present value of the future lease payments over the lease term. The Company uses its incremental borrowing rate based on the information available at the commencement date of the underlying lease arrangement to determine the present value of lease payments. The ROU asset also includes any prepaid lease payments and any lease incentives received. The lease term to calculate the ROU asset and related lease liability includes options to extend or terminate the lease when it is reasonably certain that the Company will exercise the option. The Company’s lease agreements generally do not contain any material variable lease payments, residual value guarantees or restrictive covenants. Lease expense for operating leases is recognized on a straight-line basis over the lease term as an operating expense while expense for financing leases is recognized as depreciation expense and interest expense using the accelerated interest method of recognition. When an arrangement requires payments for lease and non-lease components, the Company has elected to account for lease and non-lease components separately. Lease expense for leases with a term of twelve months or less is recognized on a straight-line basis. Derivatives and Hedging Activities The Company accounts for its derivative instruments as either assets or liabilities on the balance sheet and measures them at fair value, which is estimated using current exchange rates and interest rates, and takes into consideration the current creditworthiness of the counterparties or the Company, as applicable. For derivatives designated as hedging instruments, the entire change in the fair value of qualifying derivative instruments is recorded in Accumulated Other Comprehensive Income (AOCI) and amounts deferred in AOCI will be reclassified to earnings in the same line item in which the earnings effect of the hedged item is reported. Derivatives not designated as hedging instruments are adjusted to fair value through earnings in Operating Expenses in the Consolidated Statements of Comprehensive Loss.

RECENT ACCOUNTING PRONOUNCEMENT

RECENT ACCOUNTING PRONOUNCEMENTS	3 Months Ended
	Mar. 31, 2019
New Accounting Pronouncements And Changes In Accounting Principles [Abstract]
RECENT ACCOUNTING PRONOUNCEMENTS	(4) RECENT ACCOUNTING PRONOUNCEMENTS Except as described in Note 2 – Basis of Presentation

FINANCIAL INSTRUMENTS

FINANCIAL INSTRUMENTS	3 Months Ended
	Mar. 31, 2019
Investments Debt And Equity Securities [Abstract]
FINANCIAL INSTRUMENTS	(5) FINANCIAL INSTRUMENTS All marketable securities were classified as available-for-sale at March 31, 2019 and December 31, 2018. The following tables show the Company’s cash, cash equivalents and available-for-sale securities by significant investment category as of March 31, 2019 and December 31, 2018, respectively: Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Aggregate Fair Value Cash and Cash Equivalents Short-term Marketable Securities (1) Long-term Marketable Securities (2) Level 1: Cash $ 220,980 $ — $ — $ 220,980 $ 220,980 $ — $ — Level 2: Money market instruments 122,400 — — 122,400 122,400 — — Corporate debt securities 563,691 1,535 (765 ) 564,461 — 309,721 254,740 Commercial paper 84,584 — 84,584 20,989 63,595 — U.S. government agency securities 222,183 430 (369 ) 222,244 — 157,169 65,075 Foreign and other 50 136 (1 ) 185 — — 185 Subtotal 992,908 2,101 (1,135 ) 993,874 143,389 530,485 320,000 Total $ 1,213,888 $ 2,101 $ (1,135 ) $ 1,214,854 $ 364,369 $ 530,485 $ 320,000 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Aggregate Fair Value Cash and Cash Equivalents Short-term Marketable Securities (1) Long-term Marketable Securities (2) Level 1: Cash $ 228,809 $ — $ — $ 228,809 $ 228,809 $ — $ — Level 2: Money market instruments 205,736 — — 205,736 205,736 — — Corporate debt securities 564,852 214 (2,288 ) 562,778 2,000 376,545 184,233 Commercial paper 77,702 — — 77,702 21,964 55,738 — U.S. government agency securities 240,436 144 (697 ) 239,883 31,474 156,967 51,442 Foreign and other 5,126 139 (1 ) 5,264 3999 1,076 189 Subtotal 1,093,852 497 (2,986 ) 1,091,363 265,173 590,326 235,864 Total $ 1,322,661 $ 497 $ (2,986 ) $ 1,320,172 $ 493,982 $ 590,326 $ 235,864 (1) (2) As of March 31, 2019, the Company’s investments in an unrealized loss position were not significant, and since the Company has the ability and intent to hold all investments that have been in a continuous loss position until maturity or recovery, no other-than-temporary impairment was deemed to have occurred.

INTANGIBLE ASSETS

INTANGIBLE ASSETS	3 Months Ended
	Mar. 31, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
INTANGIBLE ASSETS	(6) INTANGIBLE ASSETS Intangible assets consisted of the following: March 31, December 31, 2019 2018 Intangible assets: Finite-lived intangible assets $ 309,702 $ 307,995 Indefinite-lived intangible assets 326,359 326,359 Gross intangible assets: 636,061 634,354 Less: Accumulated amortization (150,080 ) (142,546 ) Net carrying value $ 485,981 $ 491,808

PROPERTY, PLANT AND EQUIPMENT

PROPERTY, PLANT AND EQUIPMENT	3 Months Ended
	Mar. 31, 2019
Property Plant And Equipment [Abstract]
PROPERTY, PLANT AND EQUIPMENT	(7) PROPERTY, PLANT AND EQUIPMENT Property, plant and equipment, net consisted of the following: March 31, December 31, 2019 2018 Building and improvements $ 698,231 $ 694,447 Manufacturing and laboratory equipment 349,967 345,947 Computer hardware and software 161,063 157,787 Leasehold improvements 42,201 41,188 Furniture and equipment 33,667 33,234 Land improvements 7,213 6,551 Land 77,993 77,993 Construction-in-progress 75,405 64,170 1,445,740 1,421,317 Accumulated depreciation (493,850 ) (472,635 ) Total property, plant and equipment, net $ 951,890 $ 948,682 The construction-in-process balance primarily includes costs related to the Company’s significant in-process projects at its facilities in Marin County, California, and in Shanbally, Ireland. Depreciation expense for the three months ended March 31, 2019 was $21.4 million, of which $6.5 million was capitalized into inventory. Depreciation expense for the three months ended March 31, 2018 was $20.0 million, of which $4.0 million was capitalized into inventory.

SUPPLEMENTAL BALANCE SHEET INFO

SUPPLEMENTAL BALANCE SHEET INFORMATION	3 Months Ended
	Mar. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
SUPPLEMENTAL BALANCE SHEET INFORMATION	(8) SUPPLEMENTAL BALANCE SHEET INFORMATION Inventory consisted of the following: March 31, December 31, 2019 2018 Raw materials $ 60,427 $ 74,616 Work-in-process 282,802 231,064 Finished goods 191,467 225,191 Total inventory $ 534,696 $ 530,871 Accounts Payable and Accrued Liabilities consisted of the following: March 31, December 31, 2019 2018 Accounts payable and accrued operating expenses $ 224,385 $ 207,620 Accrued compensation expense 87,260 149,937 Accrued rebates payable 46,109 43,116 Accrued royalties payable 19,223 19,977 Value added taxes payable 11,351 7,785 Forward foreign currency exchange contracts 6,904 4,178 Lease liability 9,210 — Other 8,388 4,677 Total accounts payable and accrued liabilities $ 412,830 $ 437,290

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	(9) FAIR VALUE MEASUREMENTS The Company measures certain financial assets and liabilities at fair value in accordance with its policy in Note 3 – Significant Accounting Policies Fair Value Measurements at March 31, 2019 Quoted Price in Active Markets For Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Assets: Other current assets: NQDC Plan assets $ — $ 537 $ — $ 537 Total other current assets — 537 — 537 Other assets: NQDC Plan assets — 14,707 — 14,707 Restricted investments (1) — 2,406 — 2,406 Strategic investments (2) 1,247 — — 1,247 Total other assets 1,247 17,113 — 18,360 Total assets $ 1,247 $ 17,650 $ — $ 18,897 Liabilities: Current liabilities: NQDC Plan liability $ 639 $ 537 $ — $ 1,176 Contingent consideration — — 88,156 88,156 Total current liabilities 639 537 88,156 89,332 Other long-term liabilities: NQDC Plan liability $ 17,448 $ 14,707 — 32,155 Contingent consideration — — 48,461 48,461 Total other long-term liabilities 17,448 14,707 48,461 80,616 Total liabilities $ 18,087 $ 15,244 $ 136,617 $ 169,948 Fair Value Measurements at December 31, 2018 Quoted Price in Active Markets For Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Assets: Other current assets: NQDC Plan assets $ — $ 370 $ — $ 370 Restricted investments (1) — 9,581 — 9,581 Total other current assets — 9,951 — 9,951 Other assets: NQDC Plan assets — 12,828 — 12,828 Restricted investments (1) — 2,450 — 2,450 Strategic investments (2) 942 — — 942 Total other assets 942 15,278 — 16,220 Total assets $ 942 $ 25,229 $ — $ 26,171 Liabilities: Current liabilities: NQDC Plan liability $ 55 $ 370 $ — $ 425 Contingent consideration — — 85,951 85,951 Total current liabilities 55 370 85,951 86,376 Other long-term liabilities: NQDC Plan liability 17,598 12,828 — 30,426 Contingent consideration — — 46,883 46,883 Total other long-term liabilities 17,598 12,828 46,883 77,309 Total liabilities $ 17,653 $ 13,198 $ 132,834 $ 163,685 (1) The restricted investments at March 31, 2019 and December 31, 2018 secure the Company’s irrevocable standby letters of credit obtained in connection with certain commercial agreements. (2) The Company has investments in marketable equity securities measured using quoted prices in an active market that are considered strategic investments and included in Other Assets on the Company’s Condensed Consolidated Balance Sheets. There were no transfers between levels during the three months ended March 31, 2019. Liabilities measured at fair value on a recurring basis using Level 3 inputs includes contingent consideration. The following table represents a roll-forward of contingent consideration. Contingent consideration at December 31, 2018 $ 132,834 Changes in the fair value of other contingent consideration 12,260 Milestone payment (5,987 ) Foreign exchange remeasurement of Euro denominated contingent consideration (2,490 ) Contingent consideration at March 31, 2019 $ 136,617

DERIVATIVE INSTRUMENTS AND HEDG

DERIVATIVE INSTRUMENTS AND HEDGING STRATEGIES	3 Months Ended
	Mar. 31, 2019
Derivative Instruments And Hedging Activities Disclosure [Abstract]
DERIVATIVE INSTRUMENTS AND HEDGING STRATEGIES	(10) DERIVATIVE INSTRUMENTS AND HEDGING STRATEGIES The Company uses forward foreign currency exchange contracts (forward 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 product revenues and operating expenses being denominated in currencies other than the U.S. Dollar (USD), primarily the Euro. The Company designates certain of these forward contracts as hedging instruments and also uses forward contracts for economic hedging purposes which are not designated as hedging instruments. Whether designated or undesignated, these forward contracts protect against the reduction in value of forecasted foreign currency cash flows resulting from net product revenues, operating expenses and asset or liability positions designated in currencies other than the USD. To receive hedge accounting treatment, derivatives that hedge cash flows must be highly effective at offsetting changes to expected future cash flows on hedged transactions. The Company does not hold or issue derivative instruments for trading or speculative purposes. The following table summarizes the Company’s derivatives designated as hedging instruments outstanding as of March 31, 2019 (notional amounts in millions): Aggregate Notional Number of Amount in Foreign Exchange Contracts Contracts Foreign Currency Maturity Australian Dollars – Sell 6 2.5 Mar. 2019 - Jun. 2019 Brazilian Reais – Sell 10 147.0 May 2019 Canadian Dollars – Sell 6 7.8 Mar. 2019 - Jun. 2019 Colombian Pesos – Sell 12 105,300.0 Mar. 2019 - Mar. 2020 Euros – Purchase 151 186.1 Mar. 2019 - Feb. 2022 Euros – Sell 459 556.7 Mar. 2019 - Feb. 2022 Norwegian Krone – Sell 3 11.6 Mar. 2019 - Jun. 2019 Total 647 The following table summarizes the Company’s derivatives not designated as hedging instruments outstanding as of March 31, 2019 (notional amounts in millions): Aggregate Notional Number of Amount in Foreign Exchange Contracts Contracts Foreign Currency Maturity Brazilian Reais – Purchase 3 15.5 May 2019 Colombian Pesos – Sell 2 77,000.0 Mar. 2019 - May 2019 Euros – Purchase 7 145.8 Mar. 2019 - May 2019 Euros – Sell 1 1.0 Mar. 2019 - Apr. 2019 Great British Pounds – Purchase 1 8.2 May 2019 Rubles – Sell 2 700.0 Mar. 2019 - Apr. 2019 Total 16 The fair value carrying amounts of the Company’s derivatives, as classified within the fair value hierarchy, were as follows: Asset Derivatives Liability Derivatives March 31, 2019 March 31, 2019 Balance Sheet Location Fair Value Balance Sheet Location Fair Value Derivatives designated as hedging instruments: Level 2 (1) Forward foreign currency exchange contracts Other current assets $ 19,931 Accounts payable and accrued liabilities $ 5,177 Forward foreign currency exchange contracts Other assets 16,221 Other long-term liabilities 5,445 Total 36,152 10,622 Derivatives not designated as hedging instruments: Level 2 (1) Forward foreign currency exchange contracts Other current assets 535 Accounts payable and accrued liabilities 1,727 Forward foreign currency exchange contracts Other assets — Other long-term liabilities — Total 535 1,727 Total value of derivative contracts $ 36,687 $ 12,349 Asset Derivatives Liability Derivatives December 31, 2018 December 31, 2018 Balance Sheet Location Fair Value Balance Sheet Location Fair Value Derivatives designated as hedging instruments: Level 2 (1) Forward foreign currency exchange contracts Other current assets $ 12,686 Accounts payable and accrued liabilities $ 4,036 Forward foreign currency exchange contracts Other assets 10,324 Other long-term liabilities 3,653 Total 23,010 7,689 Derivatives not designated as hedging instruments: Level 2 (1) Forward foreign currency exchange contracts Other current assets 168 Accounts payable and accrued liabilities 142 Total 168 142 Total value of derivative contracts $ 23,178 $ 7,831 (1) For additional discussion of fair value measurements, see Note 3 – Summary of Significant Accounting Policies included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018, filed with the SEC on February 28, 2019. The following tables summarize the impact of gains and losses from the Company's derivatives designated as hedging instruments on its Condensed Consolidated Financial Statements for the period presented. Three Months Ended March 31, 2019 Amount of Gain (Loss) Recognized in Other Comprehensive Income $ 12,825 Three Months Ended March 31, 2019 Derivatives Designated as Cash Flow Hedging Instruments Cash Flow Hedging Gains (Losses) Reclassified into Earnings Net product revenues as reported $ 394,483 $ 695 Operating expenses as reported $ 454,696 $ 271 Derivatives Not Designated as Hedging Instruments Gains (Losses) Recognized in Earnings Operating Expenses $ (2,978 ) Over the next twelve months, the Company expects to reclassify unrealized gains of $10.6 million from AOCI t The Company is exposed to counterparty credit risk on all of its derivatives. 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’s exposure to potential defaults. The Company is not required to pledge collateral under these agreements.

LEASES

LEASES	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
LEASES	(11) The following table presents the Company’s right-of-use (ROU) assets and lease liabilities as of March 31, 2019: March 31, Lease Classification Classification 2019 Assets: Operating Other Assets $ 44,226 Financing Other Assets 9,204 Total ROU assets $ 53,430 Liabilities: Current: Operating Accounts payable and accrued liabilities $ 6,347 Financing Accounts payable and accrued liabilities 2,863 Noncurrent: Operating Other long-term liabilities 39,282 Financing Other long-term liabilities 8,669 Total lease liabilities $ 57,161 Maturities of lease liabilities as of March 31, 2019 by fiscal year are as follows: Maturity of Lease Liabilities Operating Financing Total 2019 $ 7,257 $ 2,521 $ 9,778 2020 8,443 3,465 11,908 2021 7,444 2,867 10,311 2022 7,079 2,259 9,338 2023 5,610 1,747 7,357 Thereafter 20,471 — 20,471 Total lease payments 56,304 12,859 69,163 Less: Interest (10,675 ) (1,327 ) (12,002 ) Present value of lease liabilities $ 45,629 $ 11,532 $ 57,161 Three Months Ended Lease Cost Classification March 31, 2019 Operating (1) Operating Expenses $ 3,080 Financing: Amortization Operating Expenses 607 Interest expense Operating Expenses 161 Total lease costs $ 3,848 (1) Includes short-term leases and variable lease costs, both of which were not material . March 31, Other Information 2019 Weighted average remaining lease term (in years): Operating leases 7.8 Financing leases 4.0 Weighted average discount rate: Operating leases 5.2 % Financing leases 5.4 % Additional leases not yet commenced (undiscounted): Operating lease liability to commence approximately mid-2019 $ 12,116 March 31, Supplemental Cash Flow Information 2019 Cash paid for amounts included in the measurement of lease liabilities: Cash used in operating activities: Operating leases $ 1,600 Financing leases $ 161 Cash used in financing activities: Financing leases $ 674 ROU assets obtained in exchange for lease obligations: Operating leases $ 19 Financing leases $ 68 Lease Commitments as of December 31, 2018 Minimum lease payments for future years as of December 31, 2018 were as follows: 2019 $ 12,976 2020 12,549 2021 11,198 2022 10,574 2023 9,993 Thereafter 27,701 Total $ 84,991 Rent expense for the year ended December 31, 2018 was $12.2 million. Deferred rent accruals at December 31, 2018 totaled $2.1 million, of which $0.5 million was current.

DEBT

DEBT	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
DEBT	(12) DEBT Convertible Notes As of March 31, 2019, the Company had outstanding fixed-rate notes with varying maturities for an undiscounted aggregate principal amount of $870.0 million (collectively the Notes). The Notes are senior subordinated convertible obligations, and interest is payable in arrears, quarterly. The following table summarizes information regarding the Company’s convertible debt: March 31, December 31, 2019 2018 1.50% senior subordinated convertible notes due in October 2020 (the 2020 Notes) 374,993 374,993 Unamortized discount (23,031 ) (26,581 ) Unamortized deferred offering costs (2,010 ) (2,334 ) Convertible Notes due in 2020, net 349,952 346,078 0.599% senior subordinated convertible notes due in August 2024 (the 2024 Notes) 495,000 495,000 Unamortized discount (7,593 ) (7,946 ) Unamortized deferred offering costs (2,593 ) (2,715 ) Convertible Notes due in 2024, net 484,814 484,339 Total convertible debt, net $ 834,766 $ 830,417 Fair value of fixed rate convertible debt Convertible Notes due in October 2020 (1) 425,216 419,722 Convertible Notes due in August 2024 (1) 505,751 491,626 Total fair value of fixed rate convertible debt $ 930,967 $ 911,348 (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. For additional discussion of fair value measurements, see Note 3 – Summary of Significant Accounting Policies included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018, filed with the SEC on February 28, 2019. Interest expense on the Company’s convertible debt consisted of the following: Three Months Ended March 31, 2019 2018 Coupon interest expense $ 2,157 $ 2,961 Amortization of debt issuance costs 507 1,004 Accretion of discount on convertible notes 3,902 7,597 Total interest expense on convertible debt $ 6,566 $ 11,562 See Note 12 to the Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018 for additional information related to the Company’s convertible debt. Revolving Credit Facility In October 2018, the Company entered into an unsecured revolving credit facility of up to $200.0 million (the 2018 Credit Facility) and terminated the 2016 Credit Facility. The 2018 Credit Facility includes a letter of credit subfacility and a swingline loan subfacility and is intended to finance ongoing working capital needs and for other general corporate purposes. Borrowings under the 2018 Credit Facility bear interest, at the Company’s option, at a rate equal to either (a) the LIBOR rate (except that if LIBOR is less than zero it shall be deemed to be zero for purposes of the 2018 Credit Facility), or LIBOR successor rate, plus an applicable margin ranging from 1.00% to 1.95% per annum, based upon the Company’s net leverage ratio and EBITDA for each of the two most recently ended four-quarter measurement periods, or (b) the Base Rate, generally the prime lending rate, plus an applicable margin ranging from 0.00% to 0.95%, based upon the Company’s net leverage ratio and EBITDA for each of the two most recently ended four-quarter measurement periods. Commitment fees payable on the undrawn amount range from 0.15% to 0.35% per annum based upon the Company’s net leverage ratio and EBITDA for each of the two most recently ended four-quarter measurement periods. The Company’s obligations under the Credit Facility are guaranteed by its direct subsidiary, California Corporate Center Acquisition LLC, and such obligations may in the future be guaranteed from time to time by certain other material domestic subsidiaries. The 2018 Credit Facility matures on October 19 , $100.0 million aggregate principal amount of the 2020 Notes remain outstanding on August 1, 2020 and certain other conditions have not been met, the Company may be required to repay all amounts borrowed under the 2018 Credit Facility on August 1, 2020.

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	3 Months Ended
	Mar. 31, 2019
Equity [Abstract]
ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	(13) ACCUMULATED OTHER COMPREHENSIVE LOSS The following table summarizes amounts reclassified out of AOCI and their effect on the Company’s Condensed Consolidated Statements of Comprehensive Loss for the three months ended March 31, 2019 and 2018. Three Months Ended March 31, Condensed Consolidated Details about AOCI Components 2019 2018 Statement of Comprehensive Loss Classification Gains (losses) on cash flow hedges: Forward foreign currency exchange contracts $ 695 $ (7,646 ) Net product revenues Forward foreign currency exchange contracts 271 1,861 Operating expenses Total gain (loss) on cash flow hedges $ 966 $ (5,785 ) The following tables summarize changes in the accumulated balances for each component of AOCI, including current period other comprehensive income (loss) and reclassifications out of AOCI for the three months ended March 31, 2019 and 2018. Three Months Ended March 31, 2019 Unrealized Gains (Losses) on Cash Flow Hedges Unrealized Gains (Losses) on Available-for-Sale Debt Securities Other Total AOCI balance at December 31, 2018 $ 7,201 $ (1,917 ) $ (13 ) $ 5,271 Other comprehensive income before reclassifications 12,825 3,455 (1 ) 16,279 Less: net gain (loss) reclassified from AOCI 966 — — 966 Tax effect — (790 ) — (790 ) Net current-period other comprehensive income (loss) 11,859 2,665 (1 ) 14,523 AOCI balance at March 31, 2019 $ 19,060 $ 748 $ (14 ) $ 19,794 Three Months Ended March 31, 2018 Unrealized Gains (Losses) on Cash Flow Hedges Unrealized Gains (Losses) on Available-for-Sale Debt Securities Other Total AOCI balance at December 31, 2017 $ (20,232 ) $ (2,722 ) $ (7 ) $ (22,961 ) Impact of change in accounting principle — (586 ) — $ (586 ) AOCI balance at January 1, 2018 $ (20,232 ) $ (3,308 ) $ (7 ) $ (23,547 ) Other comprehensive income (loss) before reclassifications (9,226 ) (2,021 ) 1 (11,246 ) Less: gain (loss) reclassified from AOCI (5,785 ) — — (5,785 ) Tax effect — 463 — 463 Net current-period other comprehensive income (loss) (3,441 ) (1,558 ) 1 (4,998 ) AOCI balance at March 31, 2018 $ (23,673 ) $ (4,866 ) $ (6 ) $ (28,545 )

REVENUE, CREDIT CONCENTRATIONS

REVENUE, CREDIT CONCENTRATIONS AND GEOGRAPHIC INFORMATION	3 Months Ended
	Mar. 31, 2019
Concentration Risk And Geographic Information [Abstract]
REVENUE, CREDIT CONCENTRATIONS AND GEOGRAPHIC INFORMATION	(14) REVENUE, CREDIT CONCENTRATIONS AND GEOGRAPHIC INFORMATION The Company operates in one business segment, which primarily focuses on the development and commercialization of innovative therapies for people with serious and life-threatening rare diseases and medical conditions. The Company considers there to be revenue concentration risks for regions where Net Product Revenues exceed 10% of consolidated net product revenues. The concentration of the Company’s Net Product Revenues within the regions below may have a material adverse effect on the Company’s revenues and results of operations if sales in the respective regions experience difficulties. The following table disaggregates Total Revenues from external customers and collaborative partners by geographic region. Net product revenues by geographic region are based on patient location for the Company’s commercial products, except for Aldurazyme. Although Genzyme Corporation (Genzyme) sells Aldurazyme worldwide, the revenues earned by the Company are included in the U.S. region, as the transactions are with Genzyme whose headquarters is located in the U.S. Genzyme is the Company’s sole customer for Aldurazyme and is responsible for marketing and selling Aldurazyme to third parties. Three Months Ended March 31, 2019 2018 Total revenues by geographic region: United States $ 190,936 $ 190,571 Europe 124,539 105,650 Latin America 33,839 38,403 Rest of world 51,431 38,823 Total revenues $ 400,745 $ 373,447 The following table disaggregates Net Product Revenues by product. Three Months Ended March 31, 2019 2018 Net product revenues by product: Aldurazyme $ 45,267 $ 66,056 Brineura 12,180 6,917 Firdapse 5,112 4,926 Kuvan 106,924 99,115 Naglazyme 86,927 74,996 Palynziq 12,272 — Vimizim 125,801 117,089 Total net product revenues $ 394,483 $ 369,099 The table below disaggregates total Net Product Revenues based on patient location for products sold directly by the Company, and global sales of Aldurazyme, which is marketed by Genzyme. Genzyme is the Company ’ Three Months Ended March 31, 2019 2018 United States $ 144,285 $ 124,141 Europe 123,085 104,798 Latin America 33,840 27,711 Rest of world 48,006 46,393 Total net product revenues marketed by the Company 349,216 303,043 Aldurazyme net product revenues marketed by Genzyme 45,267 66,056 Total net product revenues $ 394,483 $ 369,099 The following table illustrates the percentage of the Company’s total Net Product Revenues attributed to the Company’s largest customers for the periods presented. Three Months Ended March 31, 2019 2018 Customer A 18 % 17 % Customer B 12 % 18 % Customer C 11 % 12 % Customer D 11 % 8 % Total 52 % 55 % On a consolidated basis, two customers accounted for 30% and 23% of the March 31, 2019 accounts receivable balance, respectively, compared to December 31, 2018, when two customers accounted for 30% and 16% of the accounts receivable balance, respectively. As of March 31, 2019 and December 31, 2018, the accounts receivable balance for Genzyme included $88.9 million and $73.9 million, respectively, of unbilled accounts receivable, which become payable to the Company when the product is sold through by 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 sells its products in countries that face economic volatility and weakness. Although the Company has historically collected receivables from customers in such 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’s products. The Company has not historically experienced a significant level of uncollected receivables and has received continued payments from its more aged accounts in these countries. The Company believes that the allowances for doubtful accounts related to these countries, if any, is adequate based on its analysis of the specific business circumstances and expectations of collection for each of the underlying accounts in these countries.

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION	3 Months Ended
	Mar. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
STOCK-BASED COMPENSATION	(15) STOCK-BASED COMPENSATION 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 March 31, 2019 2018 Cost of sales $ 4,819 $ 3,140 R&D 13,833 13,269 Selling, general and administrative 24,109 20,199 Total stock-based compensation expense $ 42,761 $ 36,608 Stock-based compensation of $3.8 million and $3.5 million was capitalized into inventory for the three months ended March 31, 2019 and 2018, respectively. Capitalized stock-based compensation is recognized as cost of sales when the related product is sold. Equity Awards with Service-Based Vesting Conditions During the three During the three The assumptions used to estimate the per share fair value of stock options granted during the periods presented were as follows: Three Months Ended March 31, 2019 2018 Expected volatility 37.2 – 37.4% 37.8 – 38.3% Dividend yield 0.0% 0.0% Expected life 4.6 – 5.8 years 4.6 – 5.7 years Risk-free interest rate 2.4 – 3.0% 2.3 – 2.7% The Company did not issue any new stock purchase rights under the Employee Stock Purchase Plan during the three months ended March 31, 2019. Restricted Stock Unit Awards with Performance Conditions In March 2019, the Compensation Committee and Board of Directors (Board) approved the grant of 99,010 RSUs (base RSUs) with performance-based vesting conditions and a . This award is contingent upon the achievement of a 2019 revenue target and the awarded RSUs, if any, vest ratably over a three-year service period. The number of shares that may be earned range between of the base RSUs, dependent on the percentage of 2019 “managed revenues” (defined as the Company’s net product revenues, excluding net revenues attributable to Aldurazyme, and determined using fixed foreign currency exchange rates) achieved against the target managed revenues, with a threshold achievement level of RSUs with performance-based vesting conditions with similar performance conditions were granted in 2018, 2017 and 2016. Restricted Stock Unit Awards with Market Conditions In March 2019, the Compensation Committee and Board approved the grant of 99,010 RSUs (base RSU-TSRs) with market-based vesting conditions to certain executives. These RSUs, if any, vest in full following a three-year service period only if certain total shareholder return (TSR) results relative to the Nasdaq Biotechnology Index comparative companies are achieved. The number of shares that may be earned range between of the base RSU-TSRs with a

NET LOSS PER COMMON SHARE

NET LOSS PER COMMON SHARE	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
NET LOSS PER COMMON SHARE	(16) 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 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 March 31, 2019 2018 Numerator: Net loss, basic $ (56,473 ) $ (44,149 ) Less: gain on common stock held by the NQDC — 1,322 Net loss, diluted $ (56,473 ) $ (45,471 ) Denominator: Weighted-average common shares outstanding, basic 178,271 175,932 Effect of dilutive securities: Common shares held by the NQDC — 218 Weighted-average common shares outstanding, diluted 178,271 176,150 Net loss per common share, basic $ (0.32 ) $ (0.25 ) Net loss per common share, diluted $ (0.32 ) $ (0.26 ) The table below presents potential shares of common stock that were excluded from the computation of diluted earnings per common share as they were anti-dilutive using the if-converted or treasury stock method (in thousands of common shares): Three Months Ended March 31, 2019 2018 Options to purchase common stock 7,749 8,473 Common stock issuable under the 2018 Notes — 3,983 Common stock issuable under the 2020 Notes 3,983 3,983 Common stock issuable under the 2024 Notes 3,970 3,970 Unvested restricted stock units 4,164 3,734 Common stock potentially issuable for ESPP purchases 417 425 Common stock held by the NQDC 202 — Total number of potentially issuable shares 20,485 24,568 The potential effect of the capped call transactions with respect to the 2020 Notes was excluded from the diluted net loss per share as of March 31, 2019 and 2018 as the Company’s closing stock prices on March 31, 2019 and 2018, respectively, did not exceed the conversion price of $94.15 per share. The potential effect of the capped call transactions with respect to the Company’s 0.75% senior subordinated convertible notes due in 2018

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	3 Months Ended
	Mar. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	(17) COMMITMENTS AND CONTINGENCIES Contingencies From time to time the Company is involved in legal actions arising in the normal course of its business. 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. Contingent Payments As of March 31, 2019, the Company is subject to contingent payments totaling approximately $473.3 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, $151.4 million relates to the acquisition of certain rights and other assets with respect to Kuvan and Palynziq from a third party and $79.9 million relates to programs that are no longer being developed. As of March 31, 2019, the Company has recorded a total of $136.6 million of contingent consideration liabilities on its Condensed Consolidated Balances Sheet. See Note 9 to these Condensed Consolidated Financial Statements for further information regarding the fair value of the Company’s contingent consideration. Other Commitments In the normal course of business, the Company enters into various firm purchase commitments primarily related to active pharmaceutical ingredients March 31, 2019

BASIS OF PRESENTATION (Policies

BASIS OF PRESENTATION (Policies)	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Basis of Presentation	The accompanying Condensed Consolidated Financial Statements have been prepared pursuant to United States (U.S.) generally accepted accounting principles (U.S. GAAP) and 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 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, 2018 included in the Company’s Annual Report on Form 10-K. The results of operations for the three months ended March 31, 2019 are not necessarily indicative of the results that may be expected for the fiscal year ending December 31, 2019 or any other period. On January 1, 2019, the Company adopted Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) Topic 842, Leases Leases As a result of the cumulative impact of adopting ASC Topic 842, the Company recorded lease ROU assets of $55.9 million and lease liabilities of $59.0 million as of January 1, 2019, primarily related to real estate and equipment, based on the present value of future lease payments on the date of adoption. The difference between the ROU assets and lease liabilities was recorded as an adjustment to Accumulated Deficit. Refer to Note 11 for additional disclosures required by ASC Topic 842. On January 1, 2019, the Company adopted Accounting Standards Update No. 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities (ASU 2017-12), using the modified retrospective method U.S. GAAP 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. 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.
Leases	Leases The Company determines if an arrangement is a lease at inception. For leases where the Company is the lessee, ROU assets represent the Company’s right to use the underlying asset for the term of the lease and the lease liabilities represent an obligation to make lease payments arising from the lease. ROU assets and lease liabilities are recognized at the lease commencement date based on the present value of the future lease payments over the lease term. The Company uses its incremental borrowing rate based on the information available at the commencement date of the underlying lease arrangement to determine the present value of lease payments. The ROU asset also includes any prepaid lease payments and any lease incentives received. The lease term to calculate the ROU asset and related lease liability includes options to extend or terminate the lease when it is reasonably certain that the Company will exercise the option. The Company’s lease agreements generally do not contain any material variable lease payments, residual value guarantees or restrictive covenants. Lease expense for operating leases is recognized on a straight-line basis over the lease term as an operating expense while expense for financing leases is recognized as depreciation expense and interest expense using the accelerated interest method of recognition. When an arrangement requires payments for lease and non-lease components, the Company has elected to account for lease and non-lease components separately. Lease expense for leases with a term of twelve months or less is recognized on a straight-line basis.
Derivatives and Hedging Activities	Derivatives and Hedging Activities The Company accounts for its derivative instruments as either assets or liabilities on the balance sheet and measures them at fair value, which is estimated using current exchange rates and interest rates, and takes into consideration the current creditworthiness of the counterparties or the Company, as applicable. For derivatives designated as hedging instruments, the entire change in the fair value of qualifying derivative instruments is recorded in Accumulated Other Comprehensive Income (AOCI) and amounts deferred in AOCI will be reclassified to earnings in the same line item in which the earnings effect of the hedged item is reported. Derivatives not designated as hedging instruments are adjusted to fair value through earnings in Operating Expenses in the Consolidated Statements of Comprehensive Loss.

FINANCIAL INSTRUMENTS (Tables)

FINANCIAL INSTRUMENTS (Tables)	3 Months Ended
	Mar. 31, 2019
Investments Debt And Equity Securities [Abstract]
Schedule of Cash, Cash Equivalents and Available-for-Sale Securities by Significant Investment Category	The following tables show the Company’s cash, cash equivalents and available-for-sale securities by significant investment category as of March 31, 2019 and December 31, 2018, respectively: Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Aggregate Fair Value Cash and Cash Equivalents Short-term Marketable Securities (1) Long-term Marketable Securities (2) Level 1: Cash $ 220,980 $ — $ — $ 220,980 $ 220,980 $ — $ — Level 2: Money market instruments 122,400 — — 122,400 122,400 — — Corporate debt securities 563,691 1,535 (765 ) 564,461 — 309,721 254,740 Commercial paper 84,584 — 84,584 20,989 63,595 — U.S. government agency securities 222,183 430 (369 ) 222,244 — 157,169 65,075 Foreign and other 50 136 (1 ) 185 — — 185 Subtotal 992,908 2,101 (1,135 ) 993,874 143,389 530,485 320,000 Total $ 1,213,888 $ 2,101 $ (1,135 ) $ 1,214,854 $ 364,369 $ 530,485 $ 320,000 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Aggregate Fair Value Cash and Cash Equivalents Short-term Marketable Securities (1) Long-term Marketable Securities (2) Level 1: Cash $ 228,809 $ — $ — $ 228,809 $ 228,809 $ — $ — Level 2: Money market instruments 205,736 — — 205,736 205,736 — — Corporate debt securities 564,852 214 (2,288 ) 562,778 2,000 376,545 184,233 Commercial paper 77,702 — — 77,702 21,964 55,738 — U.S. government agency securities 240,436 144 (697 ) 239,883 31,474 156,967 51,442 Foreign and other 5,126 139 (1 ) 5,264 3999 1,076 189 Subtotal 1,093,852 497 (2,986 ) 1,091,363 265,173 590,326 235,864 Total $ 1,322,661 $ 497 $ (2,986 ) $ 1,320,172 $ 493,982 $ 590,326 $ 235,864 (1) (2)

INTANGIBLE ASSETS (Tables)

INTANGIBLE ASSETS (Tables)	3 Months Ended
	Mar. 31, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets	Intangible assets consisted of the following: March 31, December 31, 2019 2018 Intangible assets: Finite-lived intangible assets $ 309,702 $ 307,995 Indefinite-lived intangible assets 326,359 326,359 Gross intangible assets: 636,061 634,354 Less: Accumulated amortization (150,080 ) (142,546 ) Net carrying value $ 485,981 $ 491,808

PROPERTY, PLANT AND EQUIPMENT (

PROPERTY, PLANT AND EQUIPMENT (Tables)	3 Months Ended
	Mar. 31, 2019
Property Plant And Equipment [Abstract]
Schedule of Property Plant and Equipment Net	Property, plant and equipment, net consisted of the following: March 31, December 31, 2019 2018 Building and improvements $ 698,231 $ 694,447 Manufacturing and laboratory equipment 349,967 345,947 Computer hardware and software 161,063 157,787 Leasehold improvements 42,201 41,188 Furniture and equipment 33,667 33,234 Land improvements 7,213 6,551 Land 77,993 77,993 Construction-in-progress 75,405 64,170 1,445,740 1,421,317 Accumulated depreciation (493,850 ) (472,635 ) Total property, plant and equipment, net $ 951,890 $ 948,682

SUPPLEMENTAL BALANCE SHEET IN_2

SUPPLEMENTAL BALANCE SHEET INFORMATION (Tables)	3 Months Ended
	Mar. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Schedule of Inventory	Inventory consisted of the following: March 31, December 31, 2019 2018 Raw materials $ 60,427 $ 74,616 Work-in-process 282,802 231,064 Finished goods 191,467 225,191 Total inventory $ 534,696 $ 530,871
Schedule of Accounts Payable and Accrued Liabilities	Accounts Payable and Accrued Liabilities consisted of the following: March 31, December 31, 2019 2018 Accounts payable and accrued operating expenses $ 224,385 $ 207,620 Accrued compensation expense 87,260 149,937 Accrued rebates payable 46,109 43,116 Accrued royalties payable 19,223 19,977 Value added taxes payable 11,351 7,785 Forward foreign currency exchange contracts 6,904 4,178 Lease liability 9,210 — Other 8,388 4,677 Total accounts payable and accrued liabilities $ 412,830 $ 437,290

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value of Financial Assets and Liabilities	The Company measures certain financial assets and liabilities at fair value in accordance with its policy in Note 3 – Significant Accounting Policies Fair Value Measurements at March 31, 2019 Quoted Price in Active Markets For Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Assets: Other current assets: NQDC Plan assets $ — $ 537 $ — $ 537 Total other current assets — 537 — 537 Other assets: NQDC Plan assets — 14,707 — 14,707 Restricted investments (1) — 2,406 — 2,406 Strategic investments (2) 1,247 — — 1,247 Total other assets 1,247 17,113 — 18,360 Total assets $ 1,247 $ 17,650 $ — $ 18,897 Liabilities: Current liabilities: NQDC Plan liability $ 639 $ 537 $ — $ 1,176 Contingent consideration — — 88,156 88,156 Total current liabilities 639 537 88,156 89,332 Other long-term liabilities: NQDC Plan liability $ 17,448 $ 14,707 — 32,155 Contingent consideration — — 48,461 48,461 Total other long-term liabilities 17,448 14,707 48,461 80,616 Total liabilities $ 18,087 $ 15,244 $ 136,617 $ 169,948 Fair Value Measurements at December 31, 2018 Quoted Price in Active Markets For Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Assets: Other current assets: NQDC Plan assets $ — $ 370 $ — $ 370 Restricted investments (1) — 9,581 — 9,581 Total other current assets — 9,951 — 9,951 Other assets: NQDC Plan assets — 12,828 — 12,828 Restricted investments (1) — 2,450 — 2,450 Strategic investments (2) 942 — — 942 Total other assets 942 15,278 — 16,220 Total assets $ 942 $ 25,229 $ — $ 26,171 Liabilities: Current liabilities: NQDC Plan liability $ 55 $ 370 $ — $ 425 Contingent consideration — — 85,951 85,951 Total current liabilities 55 370 85,951 86,376 Other long-term liabilities: NQDC Plan liability 17,598 12,828 — 30,426 Contingent consideration — — 46,883 46,883 Total other long-term liabilities 17,598 12,828 46,883 77,309 Total liabilities $ 17,653 $ 13,198 $ 132,834 $ 163,685 (1) The restricted investments at March 31, 2019 and December 31, 2018 secure the Company’s irrevocable standby letters of credit obtained in connection with certain commercial agreements. (2) The Company has investments in marketable equity securities measured using quoted prices in an active market that are considered strategic investments and included in Other Assets on the Company’s Condensed Consolidated Balance Sheets.
Liabilities Measured at Fair Value on Recurring Basis Using Level 3 Inputs	Liabilities measured at fair value on a recurring basis using Level 3 inputs includes contingent consideration. The following table represents a roll-forward of contingent consideration. Contingent consideration at December 31, 2018 $ 132,834 Changes in the fair value of other contingent consideration 12,260 Milestone payment (5,987 ) Foreign exchange remeasurement of Euro denominated contingent consideration (2,490 ) Contingent consideration at March 31, 2019 $ 136,617

DERIVATIVE INSTRUMENTS AND HE_2

DERIVATIVE INSTRUMENTS AND HEDGING STRATEGIES (Tables)	3 Months Ended
	Mar. 31, 2019
Derivative [Line Items]
Fair Value Carrying Amount of Derivatives	The fair value carrying amounts of the Company’s derivatives, as classified within the fair value hierarchy, were as follows: Asset Derivatives Liability Derivatives March 31, 2019 March 31, 2019 Balance Sheet Location Fair Value Balance Sheet Location Fair Value Derivatives designated as hedging instruments: Level 2 (1) Forward foreign currency exchange contracts Other current assets $ 19,931 Accounts payable and accrued liabilities $ 5,177 Forward foreign currency exchange contracts Other assets 16,221 Other long-term liabilities 5,445 Total 36,152 10,622 Derivatives not designated as hedging instruments: Level 2 (1) Forward foreign currency exchange contracts Other current assets 535 Accounts payable and accrued liabilities 1,727 Forward foreign currency exchange contracts Other assets — Other long-term liabilities — Total 535 1,727 Total value of derivative contracts $ 36,687 $ 12,349 Asset Derivatives Liability Derivatives December 31, 2018 December 31, 2018 Balance Sheet Location Fair Value Balance Sheet Location Fair Value Derivatives designated as hedging instruments: Level 2 (1) Forward foreign currency exchange contracts Other current assets $ 12,686 Accounts payable and accrued liabilities $ 4,036 Forward foreign currency exchange contracts Other assets 10,324 Other long-term liabilities 3,653 Total 23,010 7,689 Derivatives not designated as hedging instruments: Level 2 (1) Forward foreign currency exchange contracts Other current assets 168 Accounts payable and accrued liabilities 142 Total 168 142 Total value of derivative contracts $ 23,178 $ 7,831 (1) For additional discussion of fair value measurements, see Note 3 – Summary of Significant Accounting Policies included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018, filed with the SEC on February 28, 2019.
Summary of Impact of Gains and Losses from Derivatives Designated as Hedging Instruments	The following tables summarize the impact of gains and losses from the Company's derivatives designated as hedging instruments on its Condensed Consolidated Financial Statements for the period presented. Three Months Ended March 31, 2019 Amount of Gain (Loss) Recognized in Other Comprehensive Income $ 12,825 Three Months Ended March 31, 2019 Derivatives Designated as Cash Flow Hedging Instruments Cash Flow Hedging Gains (Losses) Reclassified into Earnings Net product revenues as reported $ 394,483 $ 695 Operating expenses as reported $ 454,696 $ 271 Derivatives Not Designated as Hedging Instruments Gains (Losses) Recognized in Earnings Operating Expenses $ (2,978 )
Derivatives Designated As Hedging Instruments
Derivative [Line Items]
Summary of Derivatives Designated as Hedging Instruments Outstanding	The following table summarizes the Company’s derivatives designated as hedging instruments outstanding as of March 31, 2019 (notional amounts in millions): Aggregate Notional Number of Amount in Foreign Exchange Contracts Contracts Foreign Currency Maturity Australian Dollars – Sell 6 2.5 Mar. 2019 - Jun. 2019 Brazilian Reais – Sell 10 147.0 May 2019 Canadian Dollars – Sell 6 7.8 Mar. 2019 - Jun. 2019 Colombian Pesos – Sell 12 105,300.0 Mar. 2019 - Mar. 2020 Euros – Purchase 151 186.1 Mar. 2019 - Feb. 2022 Euros – Sell 459 556.7 Mar. 2019 - Feb. 2022 Norwegian Krone – Sell 3 11.6 Mar. 2019 - Jun. 2019 Total 647
Not Designated as Hedging Instrument
Derivative [Line Items]
Summary of Derivatives Designated as Hedging Instruments Outstanding	The following table summarizes the Company’s derivatives not designated as hedging instruments outstanding as of March 31, 2019 (notional amounts in millions): Aggregate Notional Number of Amount in Foreign Exchange Contracts Contracts Foreign Currency Maturity Brazilian Reais – Purchase 3 15.5 May 2019 Colombian Pesos – Sell 2 77,000.0 Mar. 2019 - May 2019 Euros – Purchase 7 145.8 Mar. 2019 - May 2019 Euros – Sell 1 1.0 Mar. 2019 - Apr. 2019 Great British Pounds – Purchase 1 8.2 May 2019 Rubles – Sell 2 700.0 Mar. 2019 - Apr. 2019 Total 16

LEASES (Tables)

LEASES (Tables)	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Schedule of ROU Assets and Lease Liabilities	The following table presents the Company’s right-of-use (ROU) assets and lease liabilities as of March 31, 2019: March 31, Lease Classification Classification 2019 Assets: Operating Other Assets $ 44,226 Financing Other Assets 9,204 Total ROU assets $ 53,430 Liabilities: Current: Operating Accounts payable and accrued liabilities $ 6,347 Financing Accounts payable and accrued liabilities 2,863 Noncurrent: Operating Other long-term liabilities 39,282 Financing Other long-term liabilities 8,669 Total lease liabilities $ 57,161
Schedule of Maturities of Lease Liabilities	Maturities of lease liabilities as of March 31, 2019 by fiscal year are as follows: Maturity of Lease Liabilities Operating Financing Total 2019 $ 7,257 $ 2,521 $ 9,778 2020 8,443 3,465 11,908 2021 7,444 2,867 10,311 2022 7,079 2,259 9,338 2023 5,610 1,747 7,357 Thereafter 20,471 — 20,471 Total lease payments 56,304 12,859 69,163 Less: Interest (10,675 ) (1,327 ) (12,002 ) Present value of lease liabilities $ 45,629 $ 11,532 $ 57,161
Schedule of Lease Cost	Three Months Ended Lease Cost Classification March 31, 2019 Operating (1) Operating Expenses $ 3,080 Financing: Amortization Operating Expenses 607 Interest expense Operating Expenses 161 Total lease costs $ 3,848 (1) Includes short-term leases and variable lease costs, both of which were not material .
Schedule of Other Information	March 31, Other Information 2019 Weighted average remaining lease term (in years): Operating leases 7.8 Financing leases 4.0 Weighted average discount rate: Operating leases 5.2 % Financing leases 5.4 % Additional leases not yet commenced (undiscounted): Operating lease liability to commence approximately mid-2019 $ 12,116
Schedule of Supplemental Cash Flow Information	March 31, Supplemental Cash Flow Information 2019 Cash paid for amounts included in the measurement of lease liabilities: Cash used in operating activities: Operating leases $ 1,600 Financing leases $ 161 Cash used in financing activities: Financing leases $ 674 ROU assets obtained in exchange for lease obligations: Operating leases $ 19 Financing leases $ 68
Schedule of Minimum Lease Payments for Future Years	Minimum lease payments for future years as of December 31, 2018 were as follows: 2019 $ 12,976 2020 12,549 2021 11,198 2022 10,574 2023 9,993 Thereafter 27,701 Total $ 84,991

DEBT (Tables)

DEBT (Tables)	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Summary of Convertible Debt	The following table summarizes information regarding the Company’s convertible debt: March 31, December 31, 2019 2018 1.50% senior subordinated convertible notes due in October 2020 (the 2020 Notes) 374,993 374,993 Unamortized discount (23,031 ) (26,581 ) Unamortized deferred offering costs (2,010 ) (2,334 ) Convertible Notes due in 2020, net 349,952 346,078 0.599% senior subordinated convertible notes due in August 2024 (the 2024 Notes) 495,000 495,000 Unamortized discount (7,593 ) (7,946 ) Unamortized deferred offering costs (2,593 ) (2,715 ) Convertible Notes due in 2024, net 484,814 484,339 Total convertible debt, net $ 834,766 $ 830,417 Fair value of fixed rate convertible debt Convertible Notes due in October 2020 (1) 425,216 419,722 Convertible Notes due in August 2024 (1) 505,751 491,626 Total fair value of fixed rate convertible debt $ 930,967 $ 911,348 (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. For additional discussion of fair value measurements, see Note 3 – Summary of Significant Accounting Policies included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018, filed with the SEC on February 28, 2019.
Summary of Interest Expense on Debt	Interest expense on the Company’s convertible debt consisted of the following: Three Months Ended March 31, 2019 2018 Coupon interest expense $ 2,157 $ 2,961 Amortization of debt issuance costs 507 1,004 Accretion of discount on convertible notes 3,902 7,597 Total interest expense on convertible debt $ 6,566 $ 11,562

ACCUMULATED OTHER COMPREHENSI_2

ACCUMULATED OTHER COMPREHENSIVE LOSS (Tables)	3 Months Ended
	Mar. 31, 2019
Equity [Abstract]
Amounts Reclassified out of Accumulated Other Comprehensive Income	The following table summarizes amounts reclassified out of AOCI and their effect on the Company’s Condensed Consolidated Statements of Comprehensive Loss for the three months ended March 31, 2019 and 2018. Three Months Ended March 31, Condensed Consolidated Details about AOCI Components 2019 2018 Statement of Comprehensive Loss Classification Gains (losses) on cash flow hedges: Forward foreign currency exchange contracts $ 695 $ (7,646 ) Net product revenues Forward foreign currency exchange contracts 271 1,861 Operating expenses Total gain (loss) on cash flow hedges $ 966 $ (5,785 )
Summary of Changes in Accumulated Balances of AOCI Including Current Period Other Comprehensive Income (Loss) and Reclassifications Out of AOCI	The following tables summarize changes in the accumulated balances for each component of AOCI, including current period other comprehensive income (loss) and reclassifications out of AOCI for the three months ended March 31, 2019 and 2018. Three Months Ended March 31, 2019 Unrealized Gains (Losses) on Cash Flow Hedges Unrealized Gains (Losses) on Available-for-Sale Debt Securities Other Total AOCI balance at December 31, 2018 $ 7,201 $ (1,917 ) $ (13 ) $ 5,271 Other comprehensive income before reclassifications 12,825 3,455 (1 ) 16,279 Less: net gain (loss) reclassified from AOCI 966 — — 966 Tax effect — (790 ) — (790 ) Net current-period other comprehensive income (loss) 11,859 2,665 (1 ) 14,523 AOCI balance at March 31, 2019 $ 19,060 $ 748 $ (14 ) $ 19,794 Three Months Ended March 31, 2018 Unrealized Gains (Losses) on Cash Flow Hedges Unrealized Gains (Losses) on Available-for-Sale Debt Securities Other Total AOCI balance at December 31, 2017 $ (20,232 ) $ (2,722 ) $ (7 ) $ (22,961 ) Impact of change in accounting principle — (586 ) — $ (586 ) AOCI balance at January 1, 2018 $ (20,232 ) $ (3,308 ) $ (7 ) $ (23,547 ) Other comprehensive income (loss) before reclassifications (9,226 ) (2,021 ) 1 (11,246 ) Less: gain (loss) reclassified from AOCI (5,785 ) — — (5,785 ) Tax effect — 463 — 463 Net current-period other comprehensive income (loss) (3,441 ) (1,558 ) 1 (4,998 ) AOCI balance at March 31, 2018 $ (23,673 ) $ (4,866 ) $ (6 ) $ (28,545 )

REVENUE, CREDIT CONCENTRATION_2

REVENUE, CREDIT CONCENTRATIONS AND GEOGRAPHIC INFORMATION (Tables)	3 Months Ended
	Mar. 31, 2019
Concentration Risk And Geographic Information [Abstract]
Disaggregates of Total Revenues from External Customers and Collaborative Partners by Geographic Region	The following table disaggregates Total Revenues from external customers and collaborative partners by geographic region. Net product revenues by geographic region are based on patient location for the Company’s commercial products, except for Aldurazyme. Although Genzyme Corporation (Genzyme) sells Aldurazyme worldwide, the revenues earned by the Company are included in the U.S. region, as the transactions are with Genzyme whose headquarters is located in the U.S. Genzyme is the Company’s sole customer for Aldurazyme and is responsible for marketing and selling Aldurazyme to third parties. Three Months Ended March 31, 2019 2018 Total revenues by geographic region: United States $ 190,936 $ 190,571 Europe 124,539 105,650 Latin America 33,839 38,403 Rest of world 51,431 38,823 Total revenues $ 400,745 $ 373,447
Disaggregates of Net Product Revenues by Product	The following table disaggregates Net Product Revenues by product. Three Months Ended March 31, 2019 2018 Net product revenues by product: Aldurazyme $ 45,267 $ 66,056 Brineura 12,180 6,917 Firdapse 5,112 4,926 Kuvan 106,924 99,115 Naglazyme 86,927 74,996 Palynziq 12,272 — Vimizim 125,801 117,089 Total net product revenues $ 394,483 $ 369,099
Disaggregates of Total Net Product Revenues Based on Patient Location	The table below disaggregates total Net Product Revenues based on patient location for products sold directly by the Company, and global sales of Aldurazyme, which is marketed by Genzyme. Genzyme is the Company ’ Three Months Ended March 31, 2019 2018 United States $ 144,285 $ 124,141 Europe 123,085 104,798 Latin America 33,840 27,711 Rest of world 48,006 46,393 Total net product revenues marketed by the Company 349,216 303,043 Aldurazyme net product revenues marketed by Genzyme 45,267 66,056 Total net product revenues $ 394,483 $ 369,099
Total Net Product Revenue Concentrations Attributed to Largest Customers	The following table illustrates the percentage of the Company’s total Net Product Revenues attributed to the Company’s largest customers for the periods presented. Three Months Ended March 31, 2019 2018 Customer A 18 % 17 % Customer B 12 % 18 % Customer C 11 % 12 % Customer D 11 % 8 % Total 52 % 55 %

STOCK-BASED COMPENSATION (Table

STOCK-BASED COMPENSATION (Tables)	3 Months Ended
	Mar. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
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 March 31, 2019 2018 Cost of sales $ 4,819 $ 3,140 R&D 13,833 13,269 Selling, general and administrative 24,109 20,199 Total stock-based compensation expense $ 42,761 $ 36,608
Stock Option Valuation Assumptions	The assumptions used to estimate the per share fair value of stock options granted during the periods presented were as follows: Three Months Ended March 31, 2019 2018 Expected volatility 37.2 – 37.4% 37.8 – 38.3% Dividend yield 0.0% 0.0% Expected life 4.6 – 5.8 years 4.6 – 5.7 years Risk-free interest rate 2.4 – 3.0% 2.3 – 2.7%

NET LOSS PER COMMON SHARE (Tabl

NET LOSS PER COMMON SHARE (Tables)	3 Months Ended
	Mar. 31, 2019
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 March 31, 2019 2018 Numerator: Net loss, basic $ (56,473 ) $ (44,149 ) Less: gain on common stock held by the NQDC — 1,322 Net loss, diluted $ (56,473 ) $ (45,471 ) Denominator: Weighted-average common shares outstanding, basic 178,271 175,932 Effect of dilutive securities: Common shares held by the NQDC — 218 Weighted-average common shares outstanding, diluted 178,271 176,150 Net loss per common share, basic $ (0.32 ) $ (0.25 ) Net loss per common share, diluted $ (0.32 ) $ (0.26 )
Schedule Of Anti-Dilutive Common Stock Excluded From Computation of Diluted Net Loss Per Share	The table below presents potential shares of common stock that were excluded from the computation of diluted earnings per common share as they were anti-dilutive using the if-converted or treasury stock method (in thousands of common shares): Three Months Ended March 31, 2019 2018 Options to purchase common stock 7,749 8,473 Common stock issuable under the 2018 Notes — 3,983 Common stock issuable under the 2020 Notes 3,983 3,983 Common stock issuable under the 2024 Notes 3,970 3,970 Unvested restricted stock units 4,164 3,734 Common stock potentially issuable for ESPP purchases 417 425 Common stock held by the NQDC 202 — Total number of potentially issuable shares 20,485 24,568

Basis of Presentation - Additio

Basis of Presentation - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019
Significant Accounting Policies [Line Items]
Lease ROU assets	$ 53,430
Lease liabilities	$ 57,161
ASC Topic 842
Significant Accounting Policies [Line Items]
Lease ROU assets		$ 55,900
Lease liabilities		$ 59,000

Schedule of Cash, Cash Equivale

Schedule of Cash, Cash Equivalents and Available-for-Sale Securities by Significant Investment Category (Detail) - USD ($) $ in Thousands		Mar. 31, 2019	Dec. 31, 2018		Mar. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		$ 1,213,888	$ 1,322,661
Gross Unrealized Gains		2,101	497
Gross Unrealized Losses		(1,135)	(2,986)
Aggregate Fair Value		1,214,854	1,320,172
Cash and Cash Equivalents		364,369	493,982	[1]	$ 473,980	$ 598,028
Short-term Marketable Securities	[2]	530,485	590,326	[1]
Long-term Marketable Securities	[3]	320,000	235,864	[1]
Level 1 | Cash
Schedule of Available-for-sale Securities [Line Items]
Cash		220,980	228,809
Gross Unrealized Gains		0	0
Gross Unrealized Losses		0	0
Aggregate Fair Value			228,809
Cash and Cash Equivalents		220,980	228,809
Short-term Marketable Securities	[2]	0	0
Long-term Marketable Securities	[3]	0	0
Level 2
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		992,908	1,093,852
Gross Unrealized Gains		2,101	497
Gross Unrealized Losses		(1,135)	(2,986)
Aggregate Fair Value		993,874	1,091,363
Cash and Cash Equivalents		143,389	265,173
Short-term Marketable Securities	[2]	530,485	590,326
Long-term Marketable Securities	[3]	320,000	235,864
Level 2 | Money Market Instruments
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		122,400	205,736
Gross Unrealized Gains		0	0
Gross Unrealized Losses		0	0
Aggregate Fair Value		122,400	205,736
Cash and Cash Equivalents		122,400	205,736
Short-term Marketable Securities	[2]	0	0
Long-term Marketable Securities	[3]	0	0
Level 2 | Corporate Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		563,691	564,852
Gross Unrealized Gains		1,535	214
Gross Unrealized Losses		(765)	(2,288)
Aggregate Fair Value		564,461	562,778
Cash and Cash Equivalents		0	2,000
Short-term Marketable Securities	[2]	309,721	376,545
Long-term Marketable Securities	[3]	254,740	184,233
Level 2 | Commercial Paper
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		84,584	77,702
Gross Unrealized Gains		0	0
Gross Unrealized Losses		0	0
Aggregate Fair Value		84,584	77,702
Cash and Cash Equivalents		20,989	21,964
Short-term Marketable Securities	[2]	63,595	55,738
Long-term Marketable Securities	[3]	0	0
Level 2 | U.S. Government Agency Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		222,183	240,436
Gross Unrealized Gains		430	144
Gross Unrealized Losses		(369)	(697)
Aggregate Fair Value		222,244	239,883
Cash and Cash Equivalents		0	31,474
Short-term Marketable Securities	[2]	157,169	156,967
Long-term Marketable Securities	[3]	65,075	51,442
Level 2 | Foreign and Other
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		50	5,126
Gross Unrealized Gains		136	139
Gross Unrealized Losses		(1)	(1)
Aggregate Fair Value		185	5,264
Cash and Cash Equivalents		0	3,999
Short-term Marketable Securities	[2]	0	1,076
Long-term Marketable Securities	[3]	$ 185	$ 189
[1]	December 31, 2018 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, 2018, filed with the SEC on February 28, 2019.
[2]	The Company’s short-term marketable securities mature in one year or less.
[3]	The Company’s long-term marketable securities mature between one and five years.

Schedule of Cash, Cash Equiva_2

Schedule of Cash, Cash Equivalents and Available-for-Sale Securities by Significant Investment Category (Parenthetical) (Detail)	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Minimum
Schedule of Available-for-sale Securities [Line Items]
Long-term marketable securities maturity period	1 year	1 year
Maximum
Schedule of Available-for-sale Securities [Line Items]
Short-term marketable securities maturity period	1 year	1 year
Long-term marketable securities maturity period	5 years	5 years

Financial Instruments - Additio

Financial Instruments - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2019USD ($)
Investments Debt And Equity Securities [Abstract]
Other- than- temporary impairment	$ 0

Intangible Assets (Detail)

Intangible Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Intangible assets:
Finite-lived intangible assets	$ 309,702	$ 307,995
Indefinite-lived intangible assets	326,359	326,359
Gross intangible assets:	636,061	634,354
Less: Accumulated amortization	(150,080)	(142,546)
Net carrying value	$ 485,981	$ 491,808	[1]
[1]	December 31, 2018 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, 2018, filed with the SEC on February 28, 2019.

Schedule of Property Plant and

Schedule of Property Plant and Equipment Net (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 1,445,740	$ 1,421,317
Accumulated depreciation	(493,850)	(472,635)
Total property, plant and equipment, net	951,890	948,682	[1]
Building and Improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	698,231	694,447
Manufacturing and Laboratory Equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	349,967	345,947
Computer Hardware and Software
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	161,063	157,787
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	42,201	41,188
Furniture and Equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	33,667	33,234
Land Improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	7,213	6,551
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	77,993	77,993
Construction-in-Progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 75,405	$ 64,170
[1]	December 31, 2018 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, 2018, filed with the SEC on February 28, 2019.

Property Plant and Equipment -

Property Plant and Equipment - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Property Plant And Equipment [Abstract]
Depreciation expense	$ 21.4	$ 20
Depreciation capitalized into inventory	$ 6.5	$ 4

Schedule of Inventory (Detail)

Schedule of Inventory (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Raw materials	$ 60,427	$ 74,616
Work-in-process	282,802	231,064
Finished goods	191,467	225,191
Total inventory	$ 534,696	$ 530,871	[1]
[1]	December 31, 2018 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, 2018, filed with the SEC on February 28, 2019.

Schedule of Accounts Payable an

Schedule of Accounts Payable and Accrued Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Condensed Financial Information Of Parent Company Only Disclosure [Abstract]
Accounts payable and accrued operating expenses	$ 224,385	$ 207,620
Accrued compensation expense	87,260	149,937
Accrued rebates payable	46,109	43,116
Accrued royalties payable	19,223	19,977
Value added taxes payable	11,351	7,785
Forward foreign currency exchange contracts	6,904	4,178
Lease liability	9,210	0
Other	8,388	4,677
Total accounts payable and accrued liabilities	$ 412,830	$ 437,290	[1]
[1]	December 31, 2018 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, 2018, filed with the SEC on February 28, 2019.

Fair Value of Financial Assets

Fair Value of Financial Assets and Liabilities (Detail) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands		Mar. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current assets		$ 537	$ 9,951
Fair value of other non-current assets		18,360	16,220
Fair value of financial assets, Total		18,897	26,171
Fair value of other current liabilities		89,332	86,376
Fair value of other non-current liabilities		80,616	77,309
Fair value of financial liabilities, Total		169,948	163,685
NQDC Plan Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current liabilities		1,176	425
Fair value of other non-current liabilities		32,155	30,426
Contingent Consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current liabilities		88,156	85,951
Fair value of other non-current liabilities		48,461	46,883
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 other current assets		0	0
Fair value of other non-current assets		1,247	942
Fair value of financial assets, Total		1,247	942
Fair value of other current liabilities		639	55
Fair value of other non-current liabilities		17,448	17,598
Fair value of financial liabilities, Total		18,087	17,653
Quoted Price In Active Markets For Identical Assets (Level 1) | NQDC Plan Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current liabilities		639	55
Fair value of other non-current liabilities		17,448	17,598
Quoted Price In Active Markets For Identical Assets (Level 1) | Contingent Consideration
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
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current assets		537	9,951
Fair value of other non-current assets		17,113	15,278
Fair value of financial assets, Total		17,650	25,229
Fair value of other current liabilities		537	370
Fair value of other non-current liabilities		14,707	12,828
Fair value of financial liabilities, Total		15,244	13,198
Significant Other Observable Inputs (Level 2) | NQDC Plan Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current liabilities		537	370
Fair value of other non-current liabilities		14,707	12,828
Significant Other Observable Inputs (Level 2) | Contingent Consideration
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
Significant Unobservable Inputs (Level 3)
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 of financial assets, Total		0	0
Fair value of other current liabilities		88,156	85,951
Fair value of other non-current liabilities		48,461	46,883
Fair value of financial liabilities, Total		136,617	132,834
Significant Unobservable Inputs (Level 3) | NQDC 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
Significant Unobservable Inputs (Level 3) | Contingent Consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current liabilities		88,156	85,951
Fair value of other non-current liabilities		48,461	46,883
NQDC Plan Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current assets		537	370
Fair value of other non-current assets		14,707	12,828
NQDC Plan Assets | 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 other current assets		0	0
Fair value of other non-current assets		0	0
NQDC Plan Assets | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current assets		537	370
Fair value of other non-current assets		14,707	12,828
NQDC Plan Assets | Significant Unobservable Inputs (Level 3)
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
Restricted Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current assets	[1]		9,581
Fair value of other non-current assets	[1]	2,406	2,450
Restricted Investments | 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 other current assets	[1]		0
Fair value of other non-current assets	[1]	0	0
Restricted Investments | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current assets	[1]		9,581
Fair value of other non-current assets	[1]	2,406	2,450
Restricted Investments | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other current assets	[1]		0
Fair value of other non-current assets	[1]	0	0
Strategic Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other non-current assets	[2]	1,247	942
Strategic Investments | 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 other non-current assets	[2]	1,247	942
Strategic Investments | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other non-current assets	[2]	0	0
Strategic Investments | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of other non-current assets	[2]	$ 0	$ 0
[1]	The restricted investments at March 31, 2019 and December 31, 2018 secure the Company’s irrevocable standby letters of credit obtained in connection with certain commercial agreements.
[2]	The Company has investments in marketable equity securities measured using quoted prices in an active market that are considered strategic investments and included in Other Assets on the Company’s Condensed Consolidated Balance Sheets.

Liabilities Measured at Fair Va

Liabilities Measured at Fair Value on Recurring Basis Using Level 3 Inputs (Detail) - Contingent Payment $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Contingent consideration, Beginning balance	$ 132,834
Changes in the fair value of other contingent consideration	12,260
Milestone payment	(5,987)
Foreign exchange remeasurement of Euro denominated contingent consideration	(2,490)
Contingent consideration, Ending balance	$ 136,617

Summary of Derivatives Designat

Summary of Derivatives Designated as Hedging Instruments Outstanding (Detail) - Derivatives Designated As Hedging Instruments - Foreign exchange contracts	3 Months Ended
	Mar. 31, 2019AUD ($)Derivative	Mar. 31, 2019BRL (R$)Derivative	Mar. 31, 2019CAD ($)Derivative	Mar. 31, 2019COP ($)Derivative	Mar. 31, 2019EUR (€)Derivative	Mar. 31, 2019NOK (kr)Derivative
Derivative [Line Items]
Number of Contracts	647	647	647	647	647	647
Australian Dollars | Sell
Derivative [Line Items]
Number of Contracts	6	6	6	6	6	6
Aggregate Notional Amount in Foreign Currency | $	$ 2,500,000
Australian Dollars | Minimum | Sell
Derivative [Line Items]
Maturity	Mar. 31, 2019
Australian Dollars | Maximum | Sell
Derivative [Line Items]
Maturity	Jun. 30, 2019
Canadian Dollars | Sell
Derivative [Line Items]
Number of Contracts	6	6	6	6	6	6
Aggregate Notional Amount in Foreign Currency | $			$ 7,800,000
Canadian Dollars | Minimum | Sell
Derivative [Line Items]
Maturity	Mar. 31, 2019
Canadian Dollars | Maximum | Sell
Derivative [Line Items]
Maturity	Jun. 30, 2019
Brazilian Reais | Sell
Derivative [Line Items]
Number of Contracts	10	10	10	10	10	10
Aggregate Notional Amount in Foreign Currency | R$		R$ 147000000
Maturity	May 31, 2019
Colombian Pesos | Sell
Derivative [Line Items]
Number of Contracts	12	12	12	12	12	12
Aggregate Notional Amount in Foreign Currency | $				$ 105,300,000,000
Colombian Pesos | Minimum | Sell
Derivative [Line Items]
Maturity	Mar. 31, 2019
Colombian Pesos | Maximum | Sell
Derivative [Line Items]
Maturity	Mar. 31, 2020
Euros | Sell
Derivative [Line Items]
Number of Contracts	459	459	459	459	459	459
Aggregate Notional Amount in Foreign Currency | €					€ 556,700,000
Euros | Purchase
Derivative [Line Items]
Number of Contracts	151	151	151	151	151	151
Aggregate Notional Amount in Foreign Currency | €					€ 186,100,000
Euros | Minimum | Sell
Derivative [Line Items]
Maturity	Mar. 31, 2019
Euros | Minimum | Purchase
Derivative [Line Items]
Maturity	Mar. 31, 2019
Euros | Maximum | Sell
Derivative [Line Items]
Maturity	Feb. 28, 2022
Euros | Maximum | Purchase
Derivative [Line Items]
Maturity	Feb. 28, 2022
Norwegian Krone | Sell
Derivative [Line Items]
Number of Contracts	3	3	3	3	3	3
Aggregate Notional Amount in Foreign Currency | kr						kr 11,600,000
Norwegian Krone | Minimum | Sell
Derivative [Line Items]
Maturity	Mar. 31, 2019
Norwegian Krone | Maximum | Sell
Derivative [Line Items]
Maturity	Jun. 30, 2019

Summary of Derivatives Not Desi

Summary of Derivatives Not Designated as Hedging Instruments Outstanding (Detail) - Not Designated as Hedging Instrument	3 Months Ended
	Mar. 31, 2019BRL (R$)Derivative	Mar. 31, 2019COP ($)Derivative	Mar. 31, 2019EUR (€)Derivative	Mar. 31, 2019GBP (£)Derivative	Mar. 31, 2019RUB (₽)Derivative
Derivative [Line Items]
Number of Contracts	16	16	16	16	16
Brazilian Reais | Foreign exchange contracts | Purchase
Derivative [Line Items]
Number of Contracts	3	3	3	3	3
Aggregate Notional Amount in Foreign Currency | R$	R$ 15500000
Maturity	May 31, 2019
Euros | Foreign exchange contracts | Purchase
Derivative [Line Items]
Number of Contracts	7	7	7	7	7
Aggregate Notional Amount in Foreign Currency | €			€ 145,800,000
Euros | Foreign exchange contracts | Sell
Derivative [Line Items]
Number of Contracts	1	1	1	1	1
Aggregate Notional Amount in Foreign Currency | €			€ 1,000,000
Euros | Minimum | Foreign exchange contracts | Purchase
Derivative [Line Items]
Maturity	Mar. 31, 2019
Euros | Minimum | Foreign exchange contracts | Sell
Derivative [Line Items]
Maturity	Mar. 31, 2019
Euros | Maximum | Foreign exchange contracts | Purchase
Derivative [Line Items]
Maturity	May 31, 2019
Euros | Maximum | Foreign exchange contracts | Sell
Derivative [Line Items]
Maturity	Apr. 30, 2019
Colombian Pesos | Foreign exchange contracts | Sell
Derivative [Line Items]
Number of Contracts	2	2	2	2	2
Aggregate Notional Amount in Foreign Currency | $		$ 77,000,000,000
Colombian Pesos | Minimum | Foreign exchange contracts | Sell
Derivative [Line Items]
Maturity	Mar. 31, 2019
Colombian Pesos | Maximum | Foreign exchange contracts | Sell
Derivative [Line Items]
Maturity	May 31, 2019
Rubles | Foreign exchange contracts | Sell
Derivative [Line Items]
Number of Contracts	2	2	2	2	2
Aggregate Notional Amount in Foreign Currency | ₽					₽ 700,000,000
Rubles | Minimum | Foreign exchange contracts | Sell
Derivative [Line Items]
Maturity	Mar. 31, 2019
Rubles | Maximum | Foreign exchange contracts | Sell
Derivative [Line Items]
Maturity	Apr. 30, 2019
Great British Pounds | Foreign exchange contracts | Purchase
Derivative [Line Items]
Number of Contracts	1	1	1	1	1
Aggregate Notional Amount in Foreign Currency | £				£ 8,200,000
Maturity	May 31, 2019

Fair Value Carrying Amount of D

Fair Value Carrying Amount of Derivatives (Detail) - USD ($) $ in Thousands		Mar. 31, 2019	Dec. 31, 2018
Derivative [Line Items]
Derivative Asset, Fair Value	[1]	$ 36,687	$ 23,178
Derivative Liability, Fair Value	[1]	12,349	7,831
Derivatives Designated As Hedging Instruments
Derivative [Line Items]
Derivative Asset, Fair Value	[1]	36,152	23,010
Derivative Liability, Fair Value	[1]	10,622	7,689
Derivatives Designated As Hedging Instruments | Forward Foreign Currency Exchange Contracts | Other Current Assets
Derivative [Line Items]
Derivative Asset, Fair Value	[1]	19,931	12,686
Derivatives Designated As Hedging Instruments | Forward Foreign Currency Exchange Contracts | Other Assets
Derivative [Line Items]
Derivative Asset, Fair Value	[1]	16,221	10,324
Derivatives Designated As Hedging Instruments | Forward Foreign Currency Exchange Contracts | Accounts Payable and Accrued Liabilities
Derivative [Line Items]
Derivative Liability, Fair Value	[1]	5,177	4,036
Derivatives Designated As Hedging Instruments | Forward Foreign Currency Exchange Contracts | Other Long-Term Liabilities
Derivative [Line Items]
Derivative Liability, Fair Value	[1]	5,445	3,653
Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative Asset, Fair Value	[1]	535	168
Derivative Liability, Fair Value	[1]	1,727	142
Not Designated as Hedging Instrument | Forward Foreign Currency Exchange Contracts | Other Current Assets
Derivative [Line Items]
Derivative Asset, Fair Value	[1]	535	168
Not Designated as Hedging Instrument | Forward Foreign Currency Exchange Contracts | Accounts Payable and Accrued Liabilities
Derivative [Line Items]
Derivative Liability, Fair Value	[1]	1,727	$ 142
Not Designated as Hedging Instrument | Forward Foreign Currency Exchange Contracts | Other Long-Term Liabilities
Derivative [Line Items]
Derivative Liability, Fair Value		$ 0
[1]	For additional discussion of fair value measurements, see Note 3 – Summary of Significant Accounting Policies included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018, filed with the SEC on February 28, 2019.

Summary of Impact of Gains and

Summary of Impact of Gains and Losses from Derivatives Designated as Hedging Instruments (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in Other Comprehensive Income	$ 12,825
Total revenues	400,745	$ 373,447
Operating expenses as reported	454,696	417,819
Not Designated as Hedging Instrument
Derivative Instruments Gain Loss [Line Items]
Gains (Losses) Recognized in Earnings	(2,978)
Operating Expense | Derivatives Designated As Hedging Instruments | Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent
Derivative Instruments Gain Loss [Line Items]
Cash Flow Hedging Gains (Losses) Reclassified into Earnings	271
Net Product Revenues
Derivative Instruments Gain Loss [Line Items]
Total revenues	394,483	$ 369,099
Net Product Revenues | Derivatives Designated As Hedging Instruments | Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent
Derivative Instruments Gain Loss [Line Items]
Cash Flow Hedging Gains (Losses) Reclassified into Earnings	$ 695

Derivative Instruments and He_3

Derivative Instruments and Hedging Strategies - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Maximum length of time as forecasted revenue and operating expense transactions	12 months
Amount reclassified from AOCI to earnings as related to forecasted revenue and operating expense transactions	$ 10.6

Schedule of ROU Assets and Leas

Schedule of ROU Assets and Lease Liabilities (Detail) $ in Thousands	Mar. 31, 2019USD ($)
Assets:
Operating	$ 44,226
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:OtherAssetsNoncurrent
Financing	$ 9,204
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:OtherAssetsNoncurrent
Total ROU assets	$ 53,430
Liabilities:
Operating, Current	$ 6,347
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:AccountsPayableAndAccruedLiabilitiesCurrent
Financing, Current	$ 2,863
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:AccountsPayableAndAccruedLiabilitiesCurrent
Operating and finance lease liabilities current	$ 0
Operating, Noncurrent	$ 39,282
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesNoncurrent
Financing, Noncurrent	$ 8,669
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesNoncurrent
Operating and finance lease liabilities noncurrent	$ 0
Total lease liabilities	$ 57,161

Schedule of Maturities of Lease

Schedule of Maturities of Lease Liabilities (Detail) $ in Thousands	Mar. 31, 2019USD ($)
Operating
2019	$ 7,257
2020	8,443
2021	7,444
2022	7,079
2023	5,610
Thereafter	20,471
Total lease payments	56,304
Less: Interest	(10,675)
Present value of lease liabilities	45,629
Financing
2019	2,521
2020	3,465
2021	2,867
2022	2,259
2023	1,747
Thereafter	0
Total lease payments	12,859
Less: Interest	(1,327)
Present value of lease liabilities	11,532
Total
2019	9,778
2020	11,908
2021	10,311
2022	9,338
2023	7,357
Thereafter	20,471
Total lease payments	69,163
Less: Interest	(12,002)
Present value of lease liabilities	$ 57,161

Schedule of Lease Cost (Detail)

Schedule of Lease Cost (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Financing:
Total lease costs	$ 3,848
Operating Expenses
Lease Cost
Operating	3,080	[1]
Financing:
Amortization	607
Interest expense	$ 161
[1]	Includes short-term leases and variable lease costs, both of which were not material.

Schedule of Other Information (

Schedule of Other Information (Detail) $ in Thousands	Mar. 31, 2019USD ($)
Weighted average remaining lease term (in years):
Operating leases	7 years 9 months 18 days
Financing leases	4 years
Weighted average discount rate:
Operating leases	5.20%
Financing leases	5.40%
Additional leases not yet commenced (undiscounted):
Operating lease liability to commence approximately mid-2019	$ 12,116

Schedule of Supplemental Cash F

Schedule of Supplemental Cash Flow Information (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Cash used in operating activities:
Operating leases	$ 1,600
Financing leases	161
Cash used in financing activities:
Financing leases	674
ROU assets obtained in exchange for lease obligations:
Operating leases	19
Financing leases	$ 68

Schedule of Minimum Lease Payme

Schedule of Minimum Lease Payments for Future Years (Detail) $ in Thousands	Dec. 31, 2018USD ($)
Leases [Abstract]
2019	$ 12,976
2020	12,549
2021	11,198
2022	10,574
2023	9,993
Thereafter	27,701
Total	$ 84,991

Leases - Additional Information

Leases - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)
Leases [Abstract]
Rent expense	$ 12.2
Deferred rent accruals	2.1
Deferred rent accruals, current	$ 0.5

Debt - Additional Information (

Debt - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended
	Oct. 31, 2018	Mar. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Carrying value of equity component		$ 870,000,000
The 2018 Credit Facility
Debt Instrument [Line Items]
Maturity date of convertible debt	Oct. 19, 2021
To repay early, minimum required amount outstanding with certain other conditions have not been met	$ 100,000,000
Maturity date of credit facility, if certain other conditions have not been met	Aug. 1, 2020
Debt issuance costs	$ 1,000,000
Outstanding amount		$ 0	$ 0
The 2018 Credit Facility | LIBOR Rate
Debt Instrument [Line Items]
Interest rate on deemed loan description		the LIBOR rate (except that if LIBOR is less than zero it shall be deemed to be zero for purposes of the 2018 Credit Facility)
The 2018 Credit Facility | Maximum
Debt Instrument [Line Items]
Percentage of commitment fees payable on undrawn amount	0.35%
The 2018 Credit Facility | Maximum | LIBOR Rate
Debt Instrument [Line Items]
Debt instrument interest rate percentage	1.95%
The 2018 Credit Facility | Maximum | Base Rate
Debt Instrument [Line Items]
Debt instrument interest rate percentage	0.95%
The 2018 Credit Facility | Minimum
Debt Instrument [Line Items]
Percentage of commitment fees payable on undrawn amount	0.15%
The 2018 Credit Facility | Minimum | LIBOR Rate
Debt Instrument [Line Items]
Debt instrument interest rate percentage	1.00%
The 2018 Credit Facility | Minimum | Base Rate
Debt Instrument [Line Items]
Debt instrument interest rate percentage	0.00%
The 2016 Credit Facility | Maximum
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 200,000,000

Summary of Convertible Debt (De

Summary of Convertible Debt (Detail) - USD ($) $ in Thousands		Mar. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Convertible Notes		$ 870,000
Convertible Notes, net of unamortized discount and deferred offering costs		834,766	$ 830,417	[1]
Total convertible debt, net		834,766	830,417
Total fair value of fixed rate convertible debt		930,967	911,348
1.50% Senior Subordinated Convertible Notes Due in October 2020
Debt Instrument [Line Items]
Convertible Notes		374,993	374,993
Convertible debt, unamortized discount		(23,031)	(26,581)
Convertible debt, Unamortized deferred offering costs		(2,010)	(2,334)
Convertible Notes, net of unamortized discount and deferred offering costs		349,952	346,078
Total fair value of fixed rate convertible debt	[2]	425,216	419,722
0.599% Senior Subordinated Convertible Notes Due in August 2024
Debt Instrument [Line Items]
Convertible Notes		495,000	495,000
Convertible debt, unamortized discount		(7,593)	(7,946)
Convertible debt, Unamortized deferred offering costs		(2,593)	(2,715)
Convertible Notes, net of unamortized discount and deferred offering costs		484,814	484,339
Total fair value of fixed rate convertible debt	[2]	$ 505,751	$ 491,626
[1]	December 31, 2018 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, 2018, filed with the SEC on February 28, 2019.
[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. For additional discussion of fair value measurements, see Note 3 – Summary of Significant Accounting Policies included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018, filed with the SEC on February 28, 2019.

Summary of Convertible Debt (Pa

Summary of Convertible Debt (Parenthetical) (Detail)	Mar. 31, 2019	Dec. 31, 2018
1.50% Senior Subordinated Convertible Notes Due in October 2020
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	1.50%	1.50%
0.599% Senior Subordinated Convertible Notes Due in August 2024
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	0.599%	0.599%

Summary of Interest Expense on

Summary of Interest Expense on Convertible Debt (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Schedule Of Interest Expenses [Line Items]
Total interest expense on convertible debt	$ 6,727	$ 11,562
Convertible Senior Notes
Schedule Of Interest Expenses [Line Items]
Coupon interest expense	2,157	2,961
Amortization of debt issuance costs	507	1,004
Accretion of discount on convertible notes	3,902	7,597
Total interest expense on convertible debt	$ 6,566	$ 11,562

Amounts Reclassified out of Acc

Amounts Reclassified out of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Net product revenues	$ 400,745	$ 373,447
Total gain (loss) on cash flow hedges	(53,951)	(44,372)
Net Product Revenues
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Net product revenues	394,483	369,099
Amount Reclassified from AOCI (Gain) Loss | Gains (losses) on Cash Flow Hedges
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Total gain (loss) on cash flow hedges	966	(5,785)
Amount Reclassified from AOCI (Gain) Loss | Gains (losses) on Cash Flow Hedges | Forward Foreign Currency Exchange Contracts
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Operating expenses	271	1,861
Amount Reclassified from AOCI (Gain) Loss | Gains (losses) on Cash Flow Hedges | Net Product Revenues | Forward Foreign Currency Exchange Contracts
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Net product revenues	$ 695	$ (7,646)

Summary of Changes in Accumulat

Summary of Changes in Accumulated Balances of AOCI Including Current Period Other Comprehensive Income (Loss) and Reclassifications Out of AOCI (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019		Mar. 31, 2018
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		$ 2,967,940	[1]	$ 2,808,663
Beginning Balance				(23,547)
Other comprehensive income (loss) before reclassifications		16,279		(11,246)
Less: net gain (loss) reclassified from AOCI		966		(5,785)
Tax effect		(790)		463
Net current-period other comprehensive income (loss)		14,523		(4,998)
Ending Balance		2,936,627		2,807,003
ASU 2018-02
Accumulated Other Comprehensive Income Loss [Line Items]
Impact of change in accounting principle				(586)
Unrealized Gains (Losses) on Cash Flow Hedges
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		7,201		(20,232)
Beginning Balance				(20,232)
Other comprehensive income (loss) before reclassifications		12,825		(9,226)
Less: net gain (loss) reclassified from AOCI		966		(5,785)
Tax effect		0		0
Net current-period other comprehensive income (loss)		11,859		(3,441)
Ending Balance		19,060		(23,673)
Unrealized Gains (Losses) on Cash Flow Hedges | ASU 2018-02
Accumulated Other Comprehensive Income Loss [Line Items]
Impact of change in accounting principle				0
Unrealized Gains (Losses) on Available-for-Sale Debt Securities
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		(1,917)		(2,722)
Beginning Balance				(3,308)
Other comprehensive income (loss) before reclassifications		3,455		(2,021)
Less: net gain (loss) reclassified from AOCI		0		0
Tax effect		(790)		463
Net current-period other comprehensive income (loss)		2,665		(1,558)
Ending Balance		748		(4,866)
Unrealized Gains (Losses) on Available-for-Sale Debt Securities | ASU 2018-02
Accumulated Other Comprehensive Income Loss [Line Items]
Impact of change in accounting principle				(586)
Other
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		(13)		(7)
Beginning Balance				(7)
Other comprehensive income (loss) before reclassifications		(1)		1
Less: net gain (loss) reclassified from AOCI		0		0
Tax effect		0		0
Net current-period other comprehensive income (loss)		(1)		1
Ending Balance		(14)		(6)
Other | ASU 2018-02
Accumulated Other Comprehensive Income Loss [Line Items]
Impact of change in accounting principle				0
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	[2]	5,271		(22,961)
Ending Balance		$ 19,794		$ (28,545)
[1]	December 31, 2018 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, 2018, filed with the SEC on February 28, 2019.
[2]	The beginning balances were derived from the audited Consolidated Financial Statements included in Company’s Annual Report on Form 10-K for the year ended December 31, 2018 and 2017, respectively, filed with the SEC on February 28, 2019 and February 26, 2018, respectively

Revenue, Credit Concentration_3

Revenue, Credit Concentrations and Geographic Information - Additional Information (Detail) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019USD ($)SegmentCustomer	Dec. 31, 2018USD ($)Customer
Concentration Risk And Geographic Information [Line Items]
Number of operating business segment | Segment	1
Accounts receivable, net	$ 393,429	$ 342,633	[1]
Customers
Concentration Risk And Geographic Information [Line Items]
Accounts receivable, net	$ 88,900	$ 73,900
Accounts Receivable
Concentration Risk And Geographic Information [Line Items]
Number of customers accounted for balance in accounts receivable | Customer	2	2
Geographic Concentration Risk | Net Product Revenue | Minimum
Concentration Risk And Geographic Information [Line Items]
Concentration risk, percentage	10.00%
Credit Concentration Risk | Accounts Receivable | Customer One
Concentration Risk And Geographic Information [Line Items]
Concentration risk, percentage	30.00%	30.00%
Credit Concentration Risk | Accounts Receivable | Customer Two
Concentration Risk And Geographic Information [Line Items]
Concentration risk, percentage	23.00%	16.00%
[1]	December 31, 2018 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, 2018, filed with the SEC on February 28, 2019.

Disaggregates of Total Revenues

Disaggregates of Total Revenues from External Customers and Collaborative Partners by Geographic Region (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenue from External Customer [Line Items]
Total revenues	$ 400,745	$ 373,447
United States
Revenue from External Customer [Line Items]
Total revenues	190,936	190,571
Europe
Revenue from External Customer [Line Items]
Total revenues	124,539	105,650
Latin America
Revenue from External Customer [Line Items]
Total revenues	33,839	38,403
Rest of World
Revenue from External Customer [Line Items]
Total revenues	$ 51,431	$ 38,823

Disaggregates of Net Product Re

Disaggregates of Net Product Revenues by Product (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenue from External Customer [Line Items]
Net product revenues	$ 400,745	$ 373,447
Aldurazyme
Revenue from External Customer [Line Items]
Net product revenues	45,267	66,056
Brineura
Revenue from External Customer [Line Items]
Net product revenues	12,180	6,917
Firdapse
Revenue from External Customer [Line Items]
Net product revenues	5,112	4,926
Kuvan
Revenue from External Customer [Line Items]
Net product revenues	106,924	99,115
Naglazyme
Revenue from External Customer [Line Items]
Net product revenues	86,927	74,996
Palynziq
Revenue from External Customer [Line Items]
Net product revenues	12,272	0
Vimizim
Revenue from External Customer [Line Items]
Net product revenues	125,801	117,089
Net Product Revenues
Revenue from External Customer [Line Items]
Net product revenues	$ 394,483	$ 369,099

Disaggregates of Total Net Prod

Disaggregates of Total Net Product Revenues Based on Patient Location (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation Of Revenue [Line Items]
Net product revenues	$ 400,745	$ 373,447
United States
Disaggregation Of Revenue [Line Items]
Net product revenues	190,936	190,571
Europe
Disaggregation Of Revenue [Line Items]
Net product revenues	124,539	105,650
Latin America
Disaggregation Of Revenue [Line Items]
Net product revenues	33,839	38,403
Rest of World
Disaggregation Of Revenue [Line Items]
Net product revenues	51,431	38,823
Aldurazyme
Disaggregation Of Revenue [Line Items]
Net product revenues	45,267	66,056
Net Product Revenues
Disaggregation Of Revenue [Line Items]
Net product revenues	394,483	369,099
Marketed by Company | Brineura, Firdapse, Kuvan, Naglazyme, and Vimizim
Disaggregation Of Revenue [Line Items]
Net product revenues	349,216	303,043
Marketed by Company | Brineura, Firdapse, Kuvan, Naglazyme, and Vimizim | United States
Disaggregation Of Revenue [Line Items]
Net product revenues	144,285	124,141
Marketed by Company | Brineura, Firdapse, Kuvan, Naglazyme, and Vimizim | Europe
Disaggregation Of Revenue [Line Items]
Net product revenues	123,085	104,798
Marketed by Company | Brineura, Firdapse, Kuvan, Naglazyme, and Vimizim | Latin America
Disaggregation Of Revenue [Line Items]
Net product revenues	33,840	27,711
Marketed by Company | Brineura, Firdapse, Kuvan, Naglazyme, and Vimizim | Rest of World
Disaggregation Of Revenue [Line Items]
Net product revenues	48,006	46,393
Marketed by Genzyme | Aldurazyme
Disaggregation Of Revenue [Line Items]
Net product revenues	$ 45,267	$ 66,056

Total Net Product Revenue Conce

Total Net Product Revenue Concentrations Attributed to Largest Customers (Detail) - Customer Concentration Risk - Net Product Revenue	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Concentration Risk [Line Items]
Concentration risk, percentage	52.00%	55.00%
Customer A
Concentration Risk [Line Items]
Concentration risk, percentage	18.00%	17.00%
Customer B
Concentration Risk [Line Items]
Concentration risk, percentage	12.00%	18.00%
Customer C
Concentration Risk [Line Items]
Concentration risk, percentage	11.00%	12.00%
Customer D
Concentration Risk [Line Items]
Concentration risk, percentage	11.00%	8.00%

Stock-Based Compensation Expens

Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 42,761	$ 36,608
Cost of Sales
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	4,819	3,140
R&D
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	13,833	13,269
Selling, General and Administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 24,109	$ 20,199

Stock Based Compensation - Addi

Stock Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2019	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense capitalized to inventory		$ 3.8	$ 3.5
Shares, granted		1,578,618
Weighted-average fair value per share granted		$ 94.55
New stock purchase rights issued under Employee Stock Purchase Plan		0
Restricted Stock With Service Based Vesting Conditions
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares, granted		598,950
Weighted-average fair value per RSU granted		$ 36.88
March 2019 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	$ 94.53
Granted restricted stock units	99,010	99,010
Award vesting service period	3 years
Percentage of threshold achievement	75.00%
Percentage of ceiling achievement	125.00%
March 2019 Base Restricted Stock Unit Awards with Performance Conditions | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of, number of shares may earned	0.00%
March 2019 Base Restricted Stock Unit Awards with Performance Conditions | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of, number of shares may earned	200.00%
March 2019 Base Restricted Stock Unit Awards with Market Conditions
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average fair value per RSU granted	$ 143.92
Granted restricted stock units	99,010	99,010
Award vesting service period	3 years
Percentage of ceiling achievement	100.00%
March 2019 Base Restricted Stock Unit Awards with Market Conditions | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of, number of shares may earned	0.00%
Percentage of TSR multiplier on absolute basis	50.00%
March 2019 Base Restricted Stock Unit Awards with Market Conditions | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of, number of shares may earned	200.00%

Stock Option Valuation Assumpti

Stock Option Valuation Assumptions (Detail) - Stock Option	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility, minimum	37.20%	37.80%
Expected volatility, maximum	37.40%	38.30%
Dividend yield	0.00%	0.00%
Risk-free interest rate, minimum	2.40%	2.30%
Risk-free interest rate, maximum	3.00%	2.70%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life	4 years 7 months 6 days	4 years 7 months 6 days
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life	5 years 9 months 18 days	5 years 8 months 12 days

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
	Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share [Abstract]
Net loss, basic	$ (56,473)	$ (44,149)
Less: gain on common stock held by the NQDC	0	1,322
Net loss, diluted	$ (56,473)	$ (45,471)
Weighted-average common shares outstanding, basic	178,271	175,932
Common shares held by the NQDC	0	218
Weighted-average common shares outstanding, diluted	178,271	176,150
Net loss per common share, basic	$ (0.32)	$ (0.25)
Net loss per common share, diluted	$ (0.32)	$ (0.26)

Schedule Of Anti-Dilutive Commo

Schedule Of Anti-Dilutive Common Stock Excluded From Computation of Diluted Net Loss Per Share (Detail) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
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	20,485	24,568
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	7,749	8,473
Common stock issuable under the 2018 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	0	3,983
Common stock issuable under the 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	3,983	3,983
Common stock issuable under the 2024 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	3,970	3,970
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	4,164	3,734
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	417	425
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	202	0

Net Loss Per Common Share - Add

Net Loss Per Common Share - Additional Information (Detail) - $ / shares	Mar. 31, 2019	Mar. 31, 2018
Convertible Notes due 2020
Earnings Per Share [Line Items]
Debt instrument, convertible, conversion price, per share	$ 94.15	$ 94.15
Convertible Notes due 2018
Earnings Per Share [Line Items]
Debt instrument, convertible, conversion price, per share		$ 94.15
Debt instrument, interest rate, stated percentage, per annum		0.75%

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Commitments And Contingencies [Line Items]
Contingent payments upon achievement of certain development and regulatory activities and commercial sales and licensing milestones	$ 473.3
Contingent consideration liabilities	136.6
Clinical and Post Marketing Services
Commitments And Contingencies [Line Items]
Purchase commitments and other minimum contractual obligations	111.5
Third Party
Commitments And Contingencies [Line Items]
Contingent payments upon achievement of certain development and regulatory activities and commercial sales and licensing milestones	151.4
Completed Programs | Third Party
Commitments And Contingencies [Line Items]
Contingent payments upon achievement of certain development and regulatory activities and commercial sales and licensing milestones	$ 79.9