Vertex Pharmaceuticals (VRTX) 10-K 15 Feb 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2017	Jan. 31, 2018	Jun. 30, 2017
Document and Entity Information [Abstract]
Entity Registrant Name	VERTEX PHARMACEUTICALS INC / MA
Entity Central Index Key	875,320
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Public Float			$ 31.8
Entity Common Stock, Shares Outstanding		253,891,984
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues:
Product revenues, net	$ 621,228	$ 549,642	$ 513,988	$ 480,622	$ 453,882	$ 409,689	$ 425,651	$ 394,410	$ 2,165,480	$ 1,683,632	$ 1,000,324
Royalty revenues	1,345	2,231	2,861	1,551	3,887	3,835	5,282	3,596	7,988	16,600	23,959
Collaborative revenues	29,061	26,292	27,286	232,545	937	259	675	74	315,184	1,945	8,053
Total revenues	651,634	578,165	544,135	714,718	458,706	413,783	431,608	398,080	2,488,652	1,702,177	1,032,336
Costs and expenses:
Cost of product revenues	83,712	72,186	70,535	46,242	59,646	53,222	44,154	49,789	272,675	206,811	117,151
Royalty expenses	340	688	670	746	836	855	1,098	860	2,444	3,649	7,361
Research and development expenses	306,664	454,947	289,451	273,563	248,452	272,370	271,008	255,860	1,324,625	1,047,690	995,922
Sales, general and administrative expenses	134,794	120,710	127,249	113,326	109,908	106,055	111,652	105,214	496,079	432,829	376,575
Restructuring expenses	387	337	3,523	9,999	224	8	343	687	14,246	1,262	2,206
Intangible asset impairment charge	0	255,340	0	0					255,340	0	0
Total costs and expenses	525,897	904,208	491,428	443,876	419,066	432,510	428,255	412,410	2,365,409	1,692,241	1,499,215
Income (loss) from operations	125,737	(326,043)	52,707	270,842	39,640	(18,727)	3,353	(14,330)	123,243	9,936	(466,879)
Interest expense, net	(12,547)	(13,574)	(14,664)	(16,765)	(20,439)	(20,140)	(20,155)	(20,698)	(57,550)	(81,432)	(84,206)
Other (expense) income, net	(748)	(77,553)	(2,537)	(544)	1,105	(167)	(1,219)	4,411	(81,382)	4,130	(6,715)
Loss before (benefit from) provision for income taxes	112,442	(417,170)	35,506	253,533	20,306	(39,034)	(18,021)	(30,617)	(15,689)	(67,366)	(557,800)
(Benefit from) provision for income taxes	10,257	(125,903)	4,337	3,985	(7,453)	503	18,130	5,485	(107,324)	16,665	30,381
Net income (loss)	102,185	(291,267)	31,169	249,548	27,759	(39,537)	(36,151)	(36,102)	91,635	(84,031)	(588,181)
Loss (income) attributable to noncontrolling interest	(1,501)	188,315	(13,173)	(1,792)	5,186	696	(28,374)	(5,529)	171,849	(28,021)	31,847
Net income (loss) attributable to Vertex	$ 100,684	$ (102,952)	$ 17,996	$ 247,756	$ 32,945	$ (38,841)	$ (64,525)	$ (41,631)	$ 263,484	$ (112,052)	$ (556,334)
Net income (loss):
Basic (usd per share)	$ 0.40	$ (0.41)	$ 0.07	$ 1.01	$ 0.13	$ (0.16)	$ (0.26)	$ (0.17)	$ 1.06	$ (0.46)	$ (2.31)
Diluted (usd per share)	$ 0.39	$ (0.41)	$ 0.07	$ 0.99	$ 0.13	$ (0.16)	$ (0.26)	$ (0.17)	$ 1.04	$ (0.46)	$ (2.31)
Shares used in per share calculations:
Basic (in shares)	251,557	250,268	247,521	246,024	245,454	244,920	244,482	243,831	248,858	244,685	241,312
Diluted (in shares)	256,804	250,268	251,635	248,700	247,757	244,920	244,482	243,831	253,225	244,685	241,312

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 91,635	$ (84,031)	$ (588,181)
Changes in other comprehensive income (loss):
Unrealized holding gains on marketable securities, net of tax of $(2.7) million, $(3.8) million and zero, respectively	6,954	17,395	249
Unrealized (losses) gains on foreign currency forward contracts, net of tax of $3.4 million, $(3.9) million and zero, respectively	(26,530)	7,736	1,767
Foreign currency translation adjustment	(13,169)	(5,782)	(1,109)
Total changes in other comprehensive (loss) income	(32,745)	19,349	907
Comprehensive income (loss)	58,890	(64,682)	(587,274)
Comprehensive loss (income) attributable to noncontrolling interest	171,849	(28,021)	31,847
Comprehensive income (loss) attributable to Vertex	$ 230,739	$ (92,703)	$ (555,427)

Consolidated Statements of Com4

Consolidated Statements of Comprehensive Income (Loss) (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Unrealized holding gains (losses) on marketable securities, tax	$ (2.7)	$ (3.8)	$ 0
Unrealized (losses) gains on foreign currency forward contracts, tax	$ 3.4	$ (3.9)	$ 0

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 1,665,412	$ 1,183,945
Marketable securities, available-for-sale	423,254	250,612
Restricted cash and cash equivalents (VIE)	1,489	47,762
Accounts receivable, net	281,343	200,364
Inventories	111,830	77,604
Prepaid expenses and other current assets	165,635	71,253
Total current assets	2,648,963	1,831,540
Property and equipment, net	789,437	698,362
Intangible assets	29,000	284,340
Goodwill	50,384	50,384
Cost method investments	20,447	20,276
Other assets	7,783	11,885
Total assets	3,546,014	2,896,787
Current liabilities:
Accounts payable	73,994	61,451
Accrued expenses	443,961	315,249
Deferred revenues, current portion	5,169	6,005
Accrued restructuring expense, current portion	2,175	6,047
Capital lease obligations, current portion	22,531	19,426
Customer deposits	232,401	73,416
Credit facility	0	300,000
Other liabilities, current portion	27,029	10,943
Total current liabilities	807,260	792,537
Deferred revenues, excluding current portion	1,726	6,632
Accrued restructuring expense, excluding current portion	0	1,907
Capital lease obligations, excluding current portion	20,496	34,976
Deferred tax liability	6,341	134,063
Construction financing lease obligation, excluding current portion	563,406	486,359
Advance from collaborator, excluding current portion	78,431	73,423
Other liabilities, excluding current portion	26,048	28,699
Total liabilities	1,503,708	1,558,596
Commitments and contingencies
Shareholders’ equity:
Preferred stock, $0.01 par value; 1,000,000 shares authorized; none issued and outstanding at December 31, 2017 and 2016	0	0
Common stock, $0.01 par value; 500,000,000 shares authorized, 253,253,362 and 248,300,517 shares issued and outstanding at December 31, 2017 and 2016, respectively	2,512	2,450
Additional paid-in capital	7,157,362	6,506,795
Accumulated other comprehensive (loss) income	(11,572)	21,173
Accumulated deficit	(5,119,723)	(5,373,836)
Total Vertex shareholders’ equity	2,028,579	1,156,582
Noncontrolling interest	13,727	181,609
Total shareholders’ equity	2,042,306	1,338,191
Total liabilities and shareholders’ equity	$ 3,546,014	$ 2,896,787

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Preferred stock, par value (usd per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (shares)	1,000,000	1,000,000
Preferred stock, shares issued (shares)	0	0
Preferred stock, shares outstanding (shares)	0	0
Common stock, par value (usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized (shares)	500,000,000	500,000,000
Common stock, shares issued (shares)	253,253,362	248,300,517
Common stock, shares outstanding (shares)	253,253,362	248,300,517

Consolidated Statements of Shar

Consolidated Statements of Shareholders' Equity and Noncontrolling Interest - USD ($) shares in Thousands, $ in Thousands	Total	Total Vertex Shareholders' Equity	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Noncontrolling Interest
Balance (shares) at Dec. 31, 2014			241,764
Balance at Dec. 31, 2014	$ 1,096,183	$ 1,075,006	$ 2,385	$ 5,777,154	$ 917	$ (4,705,450)	$ 21,177
Increase (Decrease) in Stockholders' Equity
Other comprehensive income, net of tax	907	907			907
Net loss	(588,181)	(556,334)				(556,334)	(31,847)
Issuance of common stock under benefit plans (shares)			4,543
Issuance of common stock under benefit plans	185,290	185,276	$ 42	185,234			14
Stock-based compensation expense	235,112	235,112		235,112			0
Noncontrolling interest upon consolidation	164,317						164,317
Balance (shares) at Dec. 31, 2015			246,307
Balance at Dec. 31, 2015	1,093,628	939,967	$ 2,427	6,197,500	1,824	(5,261,784)	153,661
Increase (Decrease) in Stockholders' Equity
Other comprehensive income, net of tax	19,349	19,349			19,349
Net loss	(84,031)	(112,052)				(112,052)	28,021
Issuance of common stock under benefit plans (shares)			1,994
Issuance of common stock under benefit plans	68,006	68,006	$ 23	67,983			0
Stock-based compensation expense	241,239	241,312		241,312			(73)
Balance (shares) at Dec. 31, 2016			248,301
Balance at Dec. 31, 2016	1,338,191	1,156,582	$ 2,450	6,506,795	21,173	(5,373,836)	181,609
Increase (Decrease) in Stockholders' Equity
Cumulative effect adjustment for adoption of new accounting guidance	0
Cumulative effect adjustment for adoption of new accounting guidance | Accounting standards update 2016-09, forfeiture rate component				9,371		(9,371)
Other comprehensive income, net of tax	(32,745)	(32,745)			(32,745)
Net loss	91,635	263,484				263,484	(171,849)
Issuance of common stock under benefit plans (shares)			4,952
Issuance of common stock under benefit plans	345,673	345,616	$ 62	345,554			57
Stock-based compensation expense	295,642	295,642		295,642			0
VIE noncontrolling interest upon deconsolidation	3,910						3,910
Balance (shares) at Dec. 31, 2017			253,253
Balance at Dec. 31, 2017	$ 2,042,306	$ 2,028,579	$ 2,512	$ 7,157,362	$ (11,572)	$ (5,119,723)	$ 13,727

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net income (loss)	$ 91,635	$ (84,031)	$ (588,181)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Stock-based compensation expense	290,736	237,705	231,025
Depreciation expense	61,397	61,398	62,343
Write-downs of inventories to net realizable value	15,292	0	0
Deferred income taxes	(120,513)	16,961	3,283
Impairment of property and equipment	1,951	0	2,516
Intangible asset impairment charge	255,340	0	0
Acquired in-process research and development	160,000	0	0
Deconsolidation of VIE	76,644	0	0
Other non-cash items, net	(2,804)	6,140	9,532
Changes in operating assets and liabilities:
Accounts receivable, net	(71,759)	(39,095)	(110,098)
Inventories	(44,984)	(16,450)	(23,146)
Prepaid expenses and other assets	(111,063)	(2,631)	(4,009)
Accounts payable	8,753	(11,745)	(1,709)
Accrued expenses and other liabilities	246,217	88,649	102,746
Accrued restructuring expense	(5,987)	(7,426)	(30,492)
Deferred revenues	(5,913)	(13,372)	(19,242)
Net cash provided by provided by (used in) operating activities	844,942	236,103	(365,432)
Cash flows from investing activities:
Maturities of marketable securities	369,214	757,562	1,067,443
Purchases of marketable securities	(532,581)	(616,625)	(633,041)
Expenditures for property and equipment	(99,421)	(56,563)	(45,302)
Purchase of in-process research and development	(160,000)	0	0
Investment in note receivable	0	(20,000)	(30,000)
Investment in equity securities	0	(13,075)	0
(Decrease) increase in restricted cash and cash equivalents (VIE)	(15,329)	31,148	11,685
Increase (decrease) in restricted cash and cash equivalents and other assets	436	22,022	(21,929)
Payment for acquisition of variable interest entity	0	0	(80,000)
Net cash (used in) provided by investing activities	(437,681)	104,469	268,856
Cash flows from financing activities:
Issuances of common stock under benefit plans	344,840	68,230	185,592
Payments on revolving credit facility	(300,000)	0	0
Advance from collaborator	12,500	75,000	0
Payments on construction financing lease obligation	(541)	(432)	(381)
Proceeds related to construction financing lease obligation	27,182	0	0
Proceeds from capital lease financing	7,484	11,208	23,662
Payments on capital lease obligations	(18,795)	(17,597)	(19,954)
Repayments of advanced funding	(4,266)	0	0
Payments on senior secured term loan	0	(75,000)	0
Proceeds from revolving credit facility	0	74,965	0
Payments of debt issuance costs	0	(3,103)	0
Net cash provided by financing activities	68,404	133,271	188,919
Effect of changes in exchange rates on cash	5,802	(4,666)	(2,834)
Net increase in cash and cash equivalents	481,467	469,177	89,509
Cash and cash equivalents—beginning of period	1,183,945	714,768	625,259
Cash and cash equivalents—end of period	1,665,412	1,183,945	714,768
Supplemental disclosure of cash flow information:
Cash paid for interest	68,696	83,656	85,613
Cash paid for (received from) income taxes	6,414	(2,579)	1,806
Non-cash investing and financing activities:
Capitalization of costs related to construction financing lease obligation	40,855	14,238	0
Issuances of common stock from employee benefit plans receivable	844	68	361
Proceeds from revolving credit facility directly paid to settle all outstanding obligations under the term loan	$ 0	$ 225,000	$ 0

Nature of Business and Accounti

Nature of Business and Accounting Policies	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Nature of Business and Accounting Policies	Nature of Business and Accounting Policies Business Vertex Pharmaceuticals Incorporated (“Vertex” or the “Company”) invests in scientific innovation to create transformative medicines for serious diseases. The Company’s business is focused on developing and commercializing therapies for the treatment of cystic fibrosis (“CF”) and advancing our research and development programs in other indications. The Company’s marketed products are ORKAMBI (lumacaftor in combination with ivacaftor), KALYDECO (ivacaftor) and SYMDEKO (tezacaftor in combination with ivacaftor), which are approved to treat patients with CF who have specific mutations in their cystic fibrosis transmembrane conductance regulator (“CFTR”) gene. As of December 31, 2017 , the Company had cash, cash equivalents and marketable securities of $2.1 billion . The Company expects that cash flows from the sales of its products, together with the Company’s cash, cash equivalents and marketable securities, will be sufficient to fund its operations for at least the next twelve months. Vertex is subject to risks common to companies in its industry including, but not limited to, the dependence on revenues from its CF products, competition, uncertainty about clinical trial outcomes and regulatory approvals, uncertainties relating to pharmaceutical pricing and reimbursement, uncertainty related to international expansion, uncertain protection of proprietary technology, the need to comply with government regulations, share price volatility, dependence on collaborative relationships and potential product liability. Basis of Presentation The consolidated financial statements reflect the operations of (i) the Company, (ii) its wholly-owned subsidiaries and (iii) consolidated variable interest entities (“VIEs”). On September 30, 2017, the Company deconsolidated Parion Sciences, Inc. (“Parion”), a VIE the Company had consolidated since June 4, 2015. The Company's consolidated balance sheet as of December 31, 2017 excludes Parion. All material intercompany balances and transactions have been eliminated. The Company operates in one segment, pharmaceuticals. Please refer to Note T, “Segment Information,” for enterprise-wide disclosures regarding the Company’s revenues, major customers and long-lived assets by geographic area. The Company has reclassified certain amounts in the consolidated balance sheets for the period ended December 31, 2016 between “Accounts receivable, net” and “Prepaid expenses and other current assets” to conform with the current year presentation. Use of Estimates The preparation of consolidated financial statements in accordance with accounting principles generally accepted in the United States of America (“GAAP”) requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the amounts of revenues and expenses during the reported periods. Significant estimates in these consolidated financial statements have been made in connection with the calculation of revenues, inventories, research and development expenses, stock-based compensation expense, the fair value of intangible assets, goodwill, noncontrolling interest, the consolidation and deconsolidation of VIEs, leases, the fair value of cash flow hedges, deferred tax asset valuation allowances and the provision for or benefit from income taxes. The Company bases its estimates on historical experience and various other assumptions, including in certain circumstances future projections, that management believes to be reasonable under the circumstances. Actual results could differ from those estimates. Changes in estimates are reflected in reported results in the period in which they become known. Revenue Recognition Product Revenues, Net The Company sells its products principally to a limited number of specialty pharmacy providers in North America as well as government-owned and supported customers in international markets (collectively, its “Customers”). The Company’s Customers in North America subsequently resell the products to patients and health care providers. The Company recognizes net revenues from product sales upon delivery as long as (i) there is persuasive evidence that an arrangement exists between the Company and the Customer, (ii) collectibility is reasonably assured and (iii) the price is fixed or determinable. In order to conclude that the price is fixed or determinable, the Company must be able to (i) calculate its gross product revenues from sales to Customers and (ii) reasonably estimate its net product revenues upon delivery to its Customer’s locations. The Company calculates gross product revenues based on the price that the Company charges its Customers. The Company estimates its net product revenues by deducting from its gross product revenues (a) trade allowances, such as invoice discounts for prompt payment and Customer fees, (b) estimated government and private payor rebates, chargebacks and discounts, (c) estimated reserves for expected product returns and (d) estimated costs of co-pay assistance programs for patients, as well as other incentives for certain indirect customers. Trade Allowances: The Company generally provides invoice discounts on product sales to its Customers for prompt payment and pays fees for distribution services, such as fees for certain data that Customers provide to the Company. The payment terms for sales to Customers in the United States (“U.S.”) generally include a discount for payment within 30 days. The Company expects that, based on its experience, its Customers will earn these discounts and fees, and deducts the full amount of these discounts and fees from its gross product revenues and accounts receivable at the time such revenues are recognized. Rebates, Chargebacks and Discounts: The Company contracts primarily with government agencies (its “Third-party Payors”) so that products will be eligible for purchase by, or partial or full reimbursement from, such Third-party Payors. The Company estimates the rebates, chargebacks and discounts it will provide to Third-party Payors and deducts these estimated amounts from its gross product revenues at the time the revenues are recognized. For each product, the Company estimates the aggregate rebates, chargebacks and discounts that it will provide to Third-party Payors based upon (i) the Company’s contracts with these Third-party Payors, (ii) the government-mandated discounts applicable to government-funded programs, (iii) information obtained from the Company’s Customers and other third-party data regarding the payor mix for such product and (iv) historical experience. Product Returns: The Company estimates the amount of each product that will be returned and deducts these estimated amounts from its gross revenues at the time the revenues are recognized. The Company’s Customers have the right to return unopened unprescribed packages, subject to contractual limitations. To date, product returns have been minimal and, based on inventory levels held by its Customers and its distribution model, the Company believes that returns of its products will continue to be minimal. Other Incentives: Other incentives that the Company offers include co-pay mitigation rebates provided by the Company to commercially insured patients who have coverage and who reside in states that permit co-pay mitigation programs. The Company’s co-pay mitigation programs are intended to reduce each participating patient’s portion of the financial responsibility for a product’s purchase price to a specified dollar amount. Based upon the terms of the Company’s co-pay mitigation programs, the Company estimates average co-pay mitigation amounts for each of its products in order to establish its accruals for co-pay mitigation rebates and deducts these estimated amounts from its gross product revenues at the later of the date (i) the revenues are recognized or (ii) the incentive is offered. The Company’s co-pay mitigation rebates are subject to expiration. The following table summarizes activity in each of the product revenue allowance and reserve categories for the three years ended December 31, 2017 : Trade Rebates, Product Other Total (in thousands) 2017 Beginning Balance $ 2,568 $ 81,927 $ 3,492 $ 1,214 $ 89,201 Provision related to current period sales 25,892 176,996 4,038 15,595 222,521 Adjustments related to prior period sales (189 ) (8,943 ) (13 ) (493 ) (9,638 ) Credits/payments made (25,507 ) (137,765 ) (4,496 ) (11,633 ) (179,401 ) Ending Balance $ 2,764 $ 112,215 $ 3,021 $ 4,683 $ 122,683 2016 Beginning Balance $ 2,089 $ 44,669 $ 1,228 $ 1,310 $ 49,296 Provision related to current period sales 20,075 134,198 3,047 6,602 163,922 Adjustments related to prior period sales (90 ) 154 (17 ) (151 ) (104 ) Credits/payments made (19,506 ) (97,094 ) (766 ) (6,547 ) (123,913 ) Ending Balance $ 2,568 $ 81,927 $ 3,492 $ 1,214 $ 89,201 2015 Beginning Balance $ 1,463 $ 29,102 $ 4,713 $ 745 $ 36,023 Provision related to current period sales 10,890 65,781 779 3,755 81,205 Adjustments related to prior period sales (214 ) (19,410 ) (993 ) (235 ) (20,852 ) Credits/payments made (10,050 ) (30,804 ) (3,271 ) (2,955 ) (47,080 ) Ending Balance $ 2,089 $ 44,669 $ 1,228 $ 1,310 $ 49,296 The Company makes significant estimates and judgments that materially affect the Company’s recognition of net product revenues. The Company adjusts its estimated rebates, chargebacks and discounts based on new information, including information regarding actual rebates, chargebacks and discounts for its products, as it becomes available. Claims by third-party payors for rebates, chargebacks and discounts frequently are submitted to the Company significantly after the related sales, potentially resulting in adjustments in the period in which the new information becomes known. In 2017, the Company’s adjustments relating to prior period sales were less than 0.5% of total net product revenues and primarily related to U.S. rebates, chargebacks and discounts. In 2016, the Company’s adjustments relating to prior period sales were insignificant. In 2015, the Company’s adjustments relating to prior period sales principally related to the Company’s estimates for INCIVEK following the Company’s withdrawal of INCIVEK from the market in the U.S. in the fourth quarter of 2014. In certain instances, the Company may be unable to reasonably conclude that the price is fixed or determinable at the time of delivery, in which case it defers the recognition of revenues. Once the Company is able to determine that the price is fixed or determinable, it recognizes the net product revenues associated with the units in which revenue recognition was deferred. French Early Access Programs The Company began distributing ORKAMBI through early access programs in France during the fourth quarter of 2015. The Company’s ORKAMBI net product revenues for the three years ended December 31, 2017 do not include any net product revenues from sales of ORKAMBI in France because the price was not fixed or determinable. As of December 31, 2017 , the Company’s consolidated balance sheet includes $232.4 million collected in France related to shipments of ORKAMBI under the early access programs that is classified as “Customer deposits.” The Company expects that the difference between the amounts collected based on the invoiced price and the final price for ORKAMBI in France will be returned to the French government. Because the Company concluded that the price was not fixed or determinable as of December 31, 2017, the amounts classified as “Customer deposits” related to shipments of ORKAMBI under early access programs will be subject to the new guidance applicable to revenue recognition that became effective January 1, 2018. Pursuant to the new guidance, the Company will record a cumulative effect adjustment to the Company’s accumulated deficit in the first quarter of 2018. The amount of the adjustment to accumulated deficit will be determined based upon (i) the status of pricing discussions in France upon adoption and (ii) the Company’s estimate of the amount of consideration the Company expects to retain related to ORKAMBI sales in France that occurred on or prior to December 31, 2017 that will not be subject to a significant reversal in amounts recognized. For ORKAMBI sales in France that occur after December 31, 2017 under the early access programs, the Company will recognize net product revenues based on the Company’s estimate of consideration the Company expects to retain that will not be subject to a significant reversal in amounts recognized. In periods after the first quarter of 2018, if the Company’s estimate regarding the amounts it will receive for ORKAMBI supplied pursuant to these programs changes, the effect of the change in estimate would be reflected in net product revenues in the period in which the change in estimate occurred. Please refer to Recent Accounting Pronouncements included in this Note A “Nature of Business and Accounting Policies” below for more information regarding the new revenue recognition guidance. Royalty Revenues The Company has sold its rights to receive certain royalties on sales of an HIV protease inhibitor (fosamprenavir) and recognizes the revenues related to this sale as royalty revenues. Pursuant to the revenue recognition guidance that was in effect until December 31, 2017, in the circumstance where the Company sold its rights to future royalties under a license agreement and also maintained continuing involvement in the royalty arrangement (but not significant continuing involvement in the generation of the cash flows payable to the purchaser of the future royalty rights), the Company deferred recognition of the proceeds it received for the royalty stream. It recognized these deferred revenues over the life of the license agreement utilizing the units-of-revenue method pursuant to this revenue recognition guidance. In the first quarter of 2018, the Company will record a $6.5 million cumulative effect adjustment to its accumulated deficit equal to the net deferred revenues and costs recorded as of December 31, 2017. This adjustment will be recorded utilizing the modified retrospective approach upon adoption of the new revenue recognition guidance described in Recent Accounting Pronouncements included in this Note A “Nature of Business and Accounting Policies” below that became effective January 1, 2018. The adjustment will be made because there are no material performance obligations remaining related to the royalty arrangement. The Company does not expect to record any royalty revenues in future periods based on sales of the HIV protease inhibitor. Please refer to Note O, “Other Arrangements” for further information related to this transaction. Collaborative Revenues The Company recognizes collaborative revenues generated through collaborative research, development and/or commercialization agreements. The terms of these agreements typically include payment to the Company of one or more of the following: nonrefundable, up-front license fees; development and commercial milestone payments; funding of research and/or development activities; and royalties on net sales of licensed products. Each of these types of payments results in collaborative revenues except for revenues from royalties on net sales of licensed products, which are classified as royalty revenues. For each collaborative research, development and/or commercialization agreement that result in revenues, the Company determines (i) whether multiple deliverables exist, (ii) whether the undelivered elements have value to the customer on a stand-alone basis, (iii) how the deliverables should be separated and (iv) how the consideration should be allocated to the deliverables. For arrangements entered into or materially modified after January 1, 2011, the Company allocates consideration in an arrangement using the relative selling price method based on management’s best estimate of selling price of deliverables if it does not have vendor-specific objective evidence or third-party evidence. As part of the accounting for these agreements, the Company must develop assumptions that require judgment to determine the best estimate of selling price. Key assumptions utilized by the Company to determine the best estimate of selling price may include forecasted revenues, patient enrollment requirements from regulatory authorities, development timelines, reimbursement rates for personnel costs, discount rates, and estimated third-party development costs. The Company evaluates amendments to its existing arrangements to determine whether they have been materially modified. In making its determination that an arrangement has been materially modified, the Company considers whether there have been significant changes to the consideration under the arrangement, the deliverables under the arrangement, the timing of deliverables and the period of the arrangement. If the arrangement is determined to have been materially modified, the Company allocates fixed consideration under the arrangement using its best estimate of selling price to the remaining undelivered elements at the date of material modification. Any consideration remaining after the allocation is recognized as revenue. Up-front License Fees: If the license to the Company’s intellectual property is determined to have stand-alone value from the other deliverables identified in the arrangement, the Company recognizes revenues from nonrefundable, up-front license fees upon delivery. If these licenses do not have stand-alone value, the Company recognizes revenues from nonrefundable, up-front license fees on a straight-line basis over the contracted or estimated period of performance. The Company evaluates the period of performance each reporting period and adjusts the period of performance on a prospective basis if there are changes to be made. Milestone Payments: At the inception of each agreement that includes research and development milestone payments, the Company evaluates whether each milestone is substantive. The Company recognizes revenues related to substantive milestones in full in the period in which the substantive milestone is achieved if payment is reasonably assured. If a milestone is not considered substantive, the Company recognizes the applicable milestone payment over the period of performance. Research and Development Activities: If the Company is entitled to reimbursement from its collaborators for specified research and development expenses, the Company determines whether the research and development funding would result in collaborative revenues or an offset to research and development expenses in accordance with the provisions of gross or net revenue presentation. Concentration of Credit Risk Financial instruments that potentially subject the Company to concentration of credit risk consist principally of money market funds and marketable securities. The Company places these investments with highly rated financial institutions, and, by policy, limits the amounts of credit exposure to any one financial institution. These amounts at times may exceed federally insured limits. The Company also maintains a foreign currency hedging program that includes foreign currency forward contracts with several counterparties. The Company has not experienced any credit losses related to these financial instruments and does not believe it is exposed to any significant credit risk related to these instruments. The Company also is subject to credit risk from its accounts receivable related to its product sales and collaborators. The Company evaluates the creditworthiness of each of its customers and has determined that all of its material customers are creditworthy. To date, the Company has not experienced significant losses with respect to the collection of its accounts receivable. The Company’s receivables from Greece, Italy, Portugal and Spain were not material as of December 31, 2017 . The Company believes that its allowance for doubtful accounts was adequate at December 31, 2017 . Please refer to Note T, “Segment Information,” for further information. Cash and Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less at the date of purchase to be cash equivalents. Marketable Securities The Company’s marketable securities consist of investments in government-sponsored enterprise securities, corporate equity securities, corporate debt securities and commercial paper that are classified as available-for-sale as of December 31, 2017 . The Company classifies marketable securities available to fund current operations as current assets on its consolidated balance sheets. Marketable securities are classified as long-term assets on the consolidated balance sheets if (i) they have been in an unrealized loss position for longer than one year and (ii) the Company has the ability and intent to hold them (a) until the carrying value is recovered and (b) such holding period may be longer than one year. The Company’s marketable securities are stated at fair value with their unrealized gains and losses included as a component of accumulated other comprehensive income (loss), which is a separate component of shareholders’ equity, until such gains and losses are realized. The fair value of these securities is based on quoted prices for identical or similar assets. The Company reviews investments in marketable securities for other-than-temporary impairment whenever the fair value of an investment is less than the amortized cost and evidence indicates that an investment’s carrying amount is not recoverable within a reasonable period of time. To determine whether an impairment is other-than-temporary, the Company considers whether it has an intent to sell, or whether it is more likely than not that the Company will be required to sell, the investment before recovery of the investment’s amortized cost basis. Evidence considered in this assessment includes reasons for the impairment, compliance with the Company’s investment policy, the severity and the duration of the impairment and changes in value subsequent to year-end. If a decline in the fair value is considered other-than-temporary, based on available evidence, the unrealized loss is transferred from other comprehensive income (loss) to the consolidated statements of operations. Realized gains and losses are determined using the specific identification method and are included in other income (expense), net in the consolidated statements of operations. Accounts Receivable The Company deducts trade allowances for prompt payment and fees for distribution services from its accounts receivable based on its experience that the Company’s Customers will earn these discounts and fees. The Company’s estimates for its allowance for doubtful accounts, which have not been significant to date, are determined based on existing contractual payment terms and historical payment patterns. Stock-based Compensation Expense The Company expenses the fair value of employee stock options and other forms of stock-based employee compensation over the associated employee service period on a straight-line basis. Stock-based compensation expense is determined based on the fair value of the award at the grant date and is adjusted each period to reflect actual forfeitures and the outcomes of certain performance conditions. For awards with performance conditions in which the award does not vest unless the performance condition is met, the Company recognizes expense if, and to the extent that, the Company estimates that achievement of the performance condition is probable. If the Company concludes that vesting is probable, it recognizes expense from the date it reaches this conclusion through the estimated vesting date. For awards with performance conditions that accelerate vesting of the award, the Company estimates the likelihood of satisfaction of the performance conditions, which affects the period over which the expense is recognized, and recognizes the expense using the accelerated attribution model. The Company provides to employees who have rendered a certain number of years’ to the Company and meet certain age requirements, partial or full acceleration of vesting of these equity awards, subject to certain conditions including a notification period, upon a termination of employment other than for cause. Less than 5% of the Company’s employees were eligible for partial or full acceleration of any of their equity awards as of December 31, 2017 . The Company recognizes stock-based compensation expense related to these awards over a service period reflecting qualified employees’ eligibility for partial or full acceleration of vesting. Research and Development Expenses The Company expenses as incurred all research and development expenses, including amounts funded by research and development collaborations. The Company capitalizes nonrefundable advance payments made by the Company for research and development activities and expenses the payments as the related goods are delivered or the related services are performed. Research and development expenses are comprised of costs incurred by the Company in performing research and development activities, including salary and benefits; stock-based compensation expense; laboratory supplies and other direct expenses; outsourced services, including clinical trial and pharmaceutical development costs; collaboration and asset acquisition payments; expenses associated with drug supplies that are not being capitalized; and infrastructure costs, including facilities costs and depreciation expense. Advertising Expenses The Company expenses the costs of advertising, including promotional expenses, as incurred. Advertising expenses, recorded in sales, general and administrative expenses, were $35.2 million , $31.4 million and $24.5 million in 2017 , 2016 and 2015 , respectively. Inventories The Company values its inventories at the lower-of-cost or net realizable value. The Company determines the cost of its inventories, which includes amounts related to materials and manufacturing overhead, on a first-in, first-out basis. The Company performs an assessment of the recoverability of capitalized inventory during each reporting period, and writes down any excess and obsolete inventories to their net realizable value in the period in which the impairment is first identified. Shipping and handling costs incurred for inventory purchases are capitalized and recorded upon sale in cost of product revenues in the consolidated statements of operations. Shipping and handling costs incurred for product shipments are recorded as incurred in cost of product revenues in the consolidated statements of operations. The Company capitalizes inventories produced in preparation for initiating sales of a drug candidate when the related drug candidate is considered to have a high likelihood of regulatory approval and the related costs are expected to be recoverable through sales of the inventories. In determining whether or not to capitalize such inventories, the Company evaluates, among other factors, information regarding the drug candidate’s safety and efficacy, the status of regulatory submissions and communications with regulatory authorities and the outlook for commercial sales, including the existence of current or anticipated competitive drugs and the availability of reimbursement. In addition, the Company evaluates risks associated with manufacturing the drug candidate and the remaining shelf-life of the inventories. Property and Equipment Property and equipment are recorded at cost. Depreciation expense is recorded using the straight-line method over the estimated useful life of the related asset, generally seven to ten years for furniture and equipment, three to five years for computers and software, 40 years for buildings and for leasehold improvements, the shorter of the useful life of the improvements or the estimated remaining life of the associated lease. Amortization expense of assets acquired under capital leases is included in depreciation expense. Maintenance and repairs to an asset that do not improve or extend its life are charged to operations. When assets are retired or otherwise disposed of, the assets and related accumulated depreciation are eliminated from the accounts and any resulting gain or loss is reflected in the Company’s consolidated statements of operations. The Company performs an assessment of the fair value of the assets if indicators of impairment are identified during a reporting period and records the assets at the lower of the net book value or the fair value of the assets. The Company capitalizes internal costs incurred to develop software for internal use during the application development stage. The Company expenses costs related to the planning and post-implementation phases of development of software for internal use as these costs are incurred. Maintenance and enhancement costs (including costs in the post-implementation stages) are expensed as incurred, unless such costs relate to substantial upgrades and enhancements to the software resulting in added functionality, in which case the costs are capitalized. Amortization of capitalized internally developed software costs is recorded in depreciation expense over the useful life of the related asset. The Company records certain construction costs incurred by a landlord as an asset and a corresponding financing obligation on the Company’s consolidated balance sheets when the Company is determined to be the owner of a building during construction for accounting purposes. Upon completion of the project, the Company performs a sale-leaseback analysis to determine if the Company can remove the assets and corresponding liability from its consolidated balance sheet. Capital Leases The assets and liabilities associated with capital lease agreements are recorded at the present value of the minimum lease payments at the inception of the lease agreement. The assets are depreciated using the straight-line method over the shorter of the useful life of the related asset or the remaining life of the associated lease. Amortization of assets that the Company leases pursuant to a capital lease is included in depreciation expense. The Company performs an assessment of the fair value of the assets if indicators of impairment are identified during a reporting period and records the assets at the lower of the net book value or the fair value of the assets. Assets recorded under capital leases are recorded within “Property and equipment, net” and liabilities related to those assets are recorded within “Capital lease obligations, current portion” and “Capital lease obligations, excluding current portion” on the Company’s consolidated balance sheets. Income Taxes Deferred tax assets and liabilities are recognized for the expected future tax consequences of temporary differences between the financial statement carrying amounts and the income tax bases of assets and liabilities. A valuation allowance is applied against any net deferred tax asset if, based on the available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. On a periodic basis, the Company reassesses the valuation allowance on its deferred income tax assets weighing positive and negative evidence to assess the recoverability of its deferred tax assets. The Company includes its recent financial performance and its future projections in this periodic assessment. The Company records liabilities related to uncertain tax positions by prescribing a minimum recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. The Company does not believe any such uncertain tax positions currently pending will have a material adverse effect on its consolidated financial statements. Variable Interest Entities The Company reviews each collaboration agreement pursuant to which it licenses assets owned by a collaborator in order to determine whether or not it has a variable interest via the license agreement with the collaborator and if the variable interest is a variable interest in the collaborator as a whole. In assessing whether the Company has a variable interest in the collaborator as a whole, the Company considers and makes judgments regarding the purpose and design of the entity, t

Collaborative Arrangements

Collaborative Arrangements	12 Months Ended
	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaborative Arrangements	Collaborative Arrangements and Acquisitions Cystic Fibrosis Foundation Therapeutics Incorporated The Company has a research, development and commercialization agreement with Cystic Fibrosis Foundation Therapeutics Incorporated (“CFFT”) that was originally entered into in May 2004, and was most recently amended in October 2016 (the “2016 Amendment”). Pursuant to the agreement, as amended, the Company has agreed to pay royalties ranging from low-single digits to mid-single digits on potential sales of certain compounds first synthesized and/or tested between March 1, 2014 and August 31, 2016, including VX-659 and VX-445, and tiered royalties ranging from single digits to sub-teens on any approved drugs first synthesized and/or tested during a research term on or before February 28, 2014, including KALYDECO (ivacaftor), ORKAMBI (lumacaftor in combination with ivacaftor) and SYMDEKO (tezacaftor in combination with ivacaftor). For combination products, such as ORKAMBI, sales will be allocated equally to each of the active pharmaceutical ingredients in the combination product. In each of the fourth quarter of 2015 and the first quarter of 2016, CFFT earned a commercial milestone payment of $13.9 million from the Company upon achievement of certain sales levels of lumacaftor. There were no commercial milestone payments in the year ended December 31, 2017, and there are no additional commercial milestone payments payable by the Company to CFFT pursuant to the agreement. Pursuant to the 2016 Amendment, the CFFT provided the Company an upfront payment of $75.0 million and agreed to provide development funding to the Company of up to $6.0 million annually. The upfront payment plus any future development funding represent a form of financing pursuant to Accounting Standards Codification (“ASC”) 730, Research and Development , and thus the amounts are recorded as a liability on the consolidated balance sheet, primarily reflected in “Advance from collaborator, excluding current portion”. The liability is reduced over the estimated royalty term of the agreement. Reductions in the liability are reflected as an offset to cost of product revenues and as interest expense. The Company began marketing KALYDECO in 2012 and began marketing ORKAMBI in 2015. The Company received approval for SYMDEKO in the United States in February 2018 and has submitted an MAA to the EMA seeking approval for tezacaftor in combination with ivacaftor in the E.U. The Company expects the EMA to complete its review of the MAA in the second half of 2018. The Company has royalty obligations to CFFT for ivacaftor, lumacaftor and tezacaftor until the expiration of patents covering those compounds. The Company has patents in the U.S. and E.U. covering the composition-of-matter of ivacaftor that expire in 2027 and 2025, respectively, subject to potential patent extensions. The Company has patents in the U.S. and E.U. covering the composition-of-matter of lumacaftor that expire in 2030 and 2026, respectively, subject to potential extension. The Company has patents in the U.S. and E.U. covering the composition-of-matter of tezacaftor that expire in 2027 and 2028, respectively, subject to potential extension. CRISPR Therapeutics AG In 2015, the Company entered into a strategic collaboration, option and license agreement (the “CRISPR Agreement”) with CRISPR Therapeutics AG and its affiliates (“CRISPR”) to collaborate on the discovery and development of potential new treatments aimed at the underlying genetic causes of human diseases using CRISPR-Cas9 gene editing technology. The Company has the exclusive right to license up to six CRISPR-Cas9-based targets. In connection with the CRISPR Agreement, the Company made an upfront payment to CRISPR of $75.0 million and a $30.0 million investment in CRISPR pursuant to a convertible loan agreement that converted into preferred stock in January 2016. The Company expensed $75.0 million to research and development, and the $30.0 million investment was recorded at cost on the Company’s consolidated balance sheet. In the second quarter of 2016, the Company made an additional preferred stock investment in CRISPR of approximately $3.1 million . In connection with CRISPR's initial public offering in October 2016, the Company purchased $10.0 million of common shares at the public offering price and the Company’s preferred stock investments in CRISPR converted into common shares. As of December 31, 2017 , the Company recorded the fair value of its investment in CRISPR common shares of $74.8 million in marketable securities and a $31.6 million unrealized gain related to these common shares in accumulated other comprehensive income (loss) on the consolidated balance sheet. In January 2018, the Company purchased an additional $21.5 million of CRISPR’s common shares. The Company funds all of the discovery activities conducted pursuant to the CRISPR Agreement. For targets that the Company elects to license, other than hemoglobinopathy treatments, the Company would lead all development and global commercialization activities. For each target that the Company elects to license, other than hemoglobinopathy targets, CRISPR has the potential to receive up to $420.0 million in development, regulatory and commercial milestones and royalties on net product sales. As part of the collaboration, the Company and CRISPR share equally all development costs and potential worldwide revenues related to potential hemoglobinopathy treatments, including treatments for of beta-thalassemia and sickle cell disease. The Company may terminate the CRISPR Agreement upon 90 days’ notice to CRISPR prior to any product receiving marketing approval or upon 270 days’ notice after a product has received marketing approval. The CRISPR Agreement also may be terminated by either party for a material breach by the other, subject to notice and cure provisions. Unless earlier terminated, the CRISPR Agreement will continue in effect until the expiration of the Company’s payment obligations under the CRISPR Agreement. In the fourth quarter of 2017, the Company entered a co-development and co-commercialization agreement with CRISPR pursuant to the terms of the CRISPR Agreement, under which the Company and CRISPR will co-develop and co-commercialize CTX001 for the treatment of hemoglobinopathy treatments, including treatments for sickle cell disease and beta-thalassemia. Merck KGaA On January 10, 2017, the Company entered into a strategic collaboration and license agreement (the “Merck KGaA Agreement”) with Merck KGaA, Darmstadt, Germany (“Merck KGaA”). Pursuant to the Merck KGaA Agreement, the Company granted Merck KGaA an exclusive worldwide license to research, develop and commercialize four oncology research and development programs. Under the Merck KGaA Agreement, the Company granted Merck KGaA exclusive, worldwide rights to two clinical-stage programs targeting DNA damage repair: its ataxia telangiectasia and Rad3-related protein inhibitor program, including VX-970 and VX-803, and its DNA-dependent protein kinase inhibitor program, including VX-984. In addition, the Company granted Merck KGaA exclusive, worldwide rights to two pre-clinical programs. The Merck KGaA Agreement provided for an upfront payment from Merck KGaA to the Company of $230.0 million . During the first quarter of 2017, the Company received $193.6 million of the upfront payment and the remaining $36.4 million was remitted to the German tax authorities. Pursuant to a tax treaty between the U.S. and Germany, the Company filed a refund application for the tax withholding. The income tax receivable is included in “Prepaid expenses and other current assets” as of December 31, 2017 . In addition to the upfront payment, the Company will receive tiered royalties on potential sales of licensed products, calculated as a percentage of net sales, that range from (i) mid-single digits to mid-twenties for clinical-stage programs and (ii) mid-single digits to high single digits for the pre-clinical research programs. Merck KGaA has assumed full responsibility for development and commercialization costs for all programs. The Company evaluated the deliverables, primarily consisting of a license to the four programs and the obligation to complete certain fully-reimbursable research and development and transition activities as directed by Merck KGaA, pursuant to the Merck KGaA Agreement, under the multiple element arrangement accounting guidance. The Company concluded that the license has stand-alone value from the research and development and transition activities based on the resources and know-how possessed by Merck KGaA, and thus concluded that there are two units of accounting in the arrangement. The Company determined the relative selling price of the units of accounting based on the Company’s best estimate of selling price. The Company utilized key assumptions to determine the best estimate of selling price for the license, which included future potential net sales of licensed products, development timelines, reimbursement rates for personnel costs, discount rates, and estimated third-party development costs. The Company utilized a discounted cash flow model to determine its best estimate of selling price for the license and determined the best estimate of selling price for the research and development and transition activities based on what it would sell the services for separately. Given the significance of the best estimate of selling price for the license as compared to the best estimate of selling price for the research and development and transition services, reasonable changes in the assumptions used in the discounted cash flow model would not have a significant impact on the relative selling price allocation. Based on this analysis, the Company recognized approximately $246.6 million in collaborative revenues related to the $230.0 million upfront payment upon delivery of the license and $16.6 million for research and development and transition activities during the year ended December 31, 2017 . The Company recorded the reimbursement for the research and development and transition activities in its consolidated statements of operations as a collaborative revenue primarily due to the fact that it is the primary obligor in the arrangement. Merck KGaA may terminate the Merck KGaA Agreement or any individual program by providing 90 days’ notice, or, in the case of termination of a program with a product that has received marketing approval, 180 days’ notice. The Merck KGaA Agreement also may be terminated by either party for a material breach by the other party, subject to notice and cure provisions. Unless earlier terminated, the Merck KGaA Agreement will continue in effect until the date on which the royalty term and all payment obligations with respect to all products in all countries have expired. Variable Interest Entities (VIE) The Company has entered into several agreements pursuant to which it has licensed rights to certain drug candidates from third-party collaborators, resulting in the consolidation of the third parties’ financial statements into the Company’s consolidated financial statements as VIEs. In order to account for the fair value of the contingent payments, which consist of milestone, royalty and option payments, related to these collaborations under GAAP, the Company uses present-value models based on assumptions regarding the probability of achieving the relevant milestones, estimates regarding the timing of achieving the milestones, estimates of future product sales and the appropriate discount rates. The Company bases its estimates of the probability of achieving the relevant milestones on industry data for similar assets and its own experience. The discount rates used in the valuation model represent a measure of credit risk and market risk associated with settling the liabilities. Significant judgment is used in determining the appropriateness of these assumptions at each reporting period. Changes in these assumptions could have a material effect on the fair value of the contingent payments. The following collaborations have been reflected in the Company’s financial statements as consolidated VIEs for portions or all of the periods presented: Parion Sciences, Inc. In June 2015, the Company entered into a strategic collaboration and license agreement (the “Parion Agreement”) with Parion Sciences, Inc. (“Parion”) to collaborate with Parion to develop investigational epithelial sodium channel (“ENaC”) inhibitors, including VX-371 (formerly P-1037) and VX-551 (formerly P-1055), for the potential treatment of CF and all other pulmonary diseases. The Company is responsible for all costs, subject to certain exceptions, related to development and commercialization of the compounds. Pursuant to the Parion Agreement, the Company has worldwide development and commercial rights to Parion’s lead investigational ENaC inhibitors, VX-371 and VX-551, for the potential treatment of CF and all other pulmonary diseases and has the option to select additional compounds discovered in Parion’s research program. In 2015, Parion received an $80.0 million up-front payment, and in 2016, Parion earned a milestone payment of $5.0 million based upon the achievement of a specified milestone under the Parion Agreement. Parion has the potential to receive up to an additional (i) $485.0 million in development and regulatory milestone payments for development of ENaC inhibitors in CF, including $360.0 million related to global filing and approval milestones, (ii) $370.0 million in development and regulatory milestones for VX-371 and VX-551 in non-CF pulmonary indications and (iii) $230.0 million in development and regulatory milestones should the Company elect to develop an additional ENaC inhibitor from Parion’s research program. The Company agreed to pay Parion tiered royalties that range from the low double digits to mid-teens as a percentage of potential sales of licensed products. The Company may terminate the Parion Agreement upon 90 days’ notice to Parion prior to any licensed product receiving marketing approval or upon 180 days’ notice after a licensed product has received marketing approval. If the Company experiences a change of control prior to the initiation of the first Phase 3 clinical trial for a licensed product, Parion may terminate the Parion Agreement upon 30 days’ notice, subject to the Company’s right to receive specified royalties on any subsequent commercialization of licensed products. The Parion Agreement also may be terminated by either party for a material breach by the other, subject to notice and cure provisions. Unless earlier terminated, the Parion Agreement will continue in effect until the expiration of the Company’s royalty obligations, which expire on a country-by-country basis on the later of (i) the date the last-to-expire patent covering a licensed product expires or (ii) ten years after the first commercial sale in the country. Following execution of the Parion Agreement, the Company determined that it had a variable interest in Parion via the Parion Agreement, and that the variable interest represented a variable interest in Parion as a whole because the fair value of the ENaC inhibitors represented more than half of the total fair value of Parion’s assets. The Company also concluded that it was the primary beneficiary as it had the power to direct the activities that most significantly affect the economic performance of Parion and that it had the obligation to absorb losses and right to receive benefits that potentially could be significant to Parion. Accordingly, the Company consolidated Parion's financial statements from June 4, 2015 until the Company deconsolidated Parion effective September 30, 2017. Notwithstanding the applicable accounting treatment, the Company's interests in Parion have been and continue to be limited to those accorded to the Company in the Parion Agreement. The effect of consolidating Parion’s financial statements included $255.3 million of intangible assets on the Company’s consolidated balance sheet for Parion’s in-process research and development assets. These in-process research and development assets relate to Parion’s pulmonary ENaC platform, including the intellectual property related to VX-371 and VX-551, that are licensed by Parion to the Company. The Company also recorded the fair value of the net assets attributable to noncontrolling interest of $164.3 million , deferred tax liability of $91.0 million resulting primarily from a basis difference in the intangible assets and certain other net liabilities held by Parion of $10.5 million . The difference between the fair values of the consideration and noncontrolling interest and the fair value of Parion’s net assets was recorded as goodwill. When determining the valuation of goodwill, the fair value of consideration for the license was zero since there was no consideration transferred outside the consolidated financial statements. While there was a transfer of $80.0 million for the upfront payment to Parion, the cash remained within the Company’s consolidated balance sheet since Parion was part of the consolidated entity. The cash received, net of any cash spent by Parion, was recorded as restricted cash and cash equivalents (VIE) within the consolidated balance sheet as it was attributed to the noncontrolling interest holders of Parion. In the second quarter of 2017, Parion signed a license agreement with an affiliate of Shire plc related to the development of a drug candidate for the potential treatment of dry eye disease. The Company evaluated the license agreement entered into by Parion as a reconsideration event to determine whether it should continue to consolidate Parion as a variable interest entity into its consolidated financial statements. The Company determined that there was no substantive change in the design of Parion subsequent to Parion’s agreement with Shire. Additionally, the Company concluded that at the time it was appropriate to continue to consolidate the financial results of Parion. Based on the consolidation of Parion’s financial statements, during the year ended December 31, 2017 , the Company recognized $40.0 million of collaborative revenues and (ii) a tax provision of $14.8 million , both of which were attributable to noncontrolling interest related to payments that Parion received from Shire in the year ended December 31, 2017 . The Company has no interest in Parion’s license agreement with Shire, including the economic benefits and/or obligations derived therefrom. As of September 30, 2017, the Company determined that the fair value of Parion’s pulmonary ENaC platform had declined significantly based on data received in September 2017 from a Phase 2 clinical trial of VX-371 that did not meet its primary efficacy endpoint. The Company recorded an impairment charge of $255.3 million , which represented the entire value of the intangible asset in the third quarter of 2017. After evaluating the results of the clinical trial and based on the decrease in the fair value of Parion’s pulmonary ENaC platform relative to Parion’s other activities, the Company determined that it was no longer the primary beneficiary of Parion as it no longer had the power to direct the significant activities of Parion. Accordingly, the Company deconsolidated Parion as of September 30, 2017. The impairment charge of $255.3 million , the decrease in the fair value of the contingent payments payable by the Company to Parion of $69.6 million and the benefit from income taxes of $126.2 million resulting from these charges were recorded in the third quarter of 2017 and were attributable to noncontrolling interest. The benefit from income taxes consisted of benefits of $97.7 million attributable to the impairment charge and $28.5 million attributable to the decrease in the fair value of contingent payments. The net effect of these charges and impact of the deconsolidation was a loss of $7.1 million recorded in other income (expense), net attributable to Vertex in the consolidated statement of operations for the year ended December 31, 2017 . The loss of $7.1 million was approximately the difference between (i) the aggregate of $85.0 million in upfront and milestone payments that the Company has made to Parion to date pursuant to the Parion Agreement and (ii) losses the Company recorded in 2015, 2016, and the first half of 2017 based on increases in the fair value of contingent payments payable by the Company to Parion. Please refer to Note J, “Intangible Assets and Goodwill,” for further information regarding the impairment of Parion’s pulmonary ENaC platform. In connection with the deconsolidation of Parion, the Company evaluated whether the results of Parion should be presented as discontinued operations for the year ending December 31, 2017. The Company concluded that the deconsolidation of Parion based on data from the Phase 2 clinical trial of VX-371 is not a development that significantly impacts the Company’s overall operations and financial results or plans to treat patients with CF. Research and development expenses incurred related to this program accounted for a minor portion of the Company’s overall annual research and development expenses and the Company remains focused on developing medicines to treat CF. Therefore, the Company has not presented the results related to Parion as discontinued operations in its consolidated statements of operations for the year ending December 31, 2017. BioAxone Biosciences, Inc. In October 2014, the Company entered into a license and collaboration agreement (the “BioAxone Agreement”) with BioAxone Biosciences, Inc. (“BioAxone”), which resulted in the consolidation of BioAxone as a VIE beginning on October 1, 2014. The Company paid BioAxone initial payments of $10.0 million in the fourth quarter of 2014. BioAxone has the potential to receive up to $90.0 million in milestones and fees, including development and regulatory milestone payments and a license continuation fee. The Company recorded an in-process research and development intangible asset of $29.0 million for VX-210 and a corresponding deferred tax liability of $11.3 million attributable to BioAxone. The Company holds an option to purchase BioAxone at a predetermined price. The option expires on the earliest of (a) the day the FDA accepts the Biologics License Application submission for VX-210, (b) the day the Company elects to continue the license instead of exercising the option to purchase BioAxone and (c) March 15, 2018, subject to the Company’s option to extend this date by one year. Aggregate VIE Financial Information An aggregate summary of net loss attributable to noncontrolling interest related to the Company’s VIEs for the three years ended December 31, 2017 was as follows: 2017 2016 2015 (in thousands) Loss attributable to noncontrolling interest before (benefit from) provision for income taxes and changes in fair value of contingent payments $ 223,379 $ 10,086 $ 6,646 (Benefit from) provision for income taxes (114,090 ) 16,743 29,731 Decrease (increase) in fair value of contingent payments 62,560 (54,850 ) (4,530 ) Net loss (income) attributable to noncontrolling interest $ 171,849 $ (28,021 ) $ 31,847 The decrease in the noncontrolling interest holders’ claim to net assets with respect to the fair value of the contingent payments for the year ended December 31, 2017 was primarily due to the decrease in the fair value of Parion’s pulmonary ENaC platform described above. The increase in the fair value of the contingent payments for the year ended December 31, 2016 was primarily due to a separate Phase 2 clinical trial of VX-371 achieving its primary safety endpoint in the second quarter of 2016. The increase in the fair value of the contingent payments for the year ended December 31, 2015 was primarily due to changes in market interest rates and the time value of money. During three years ended December 31, 2017 , the (increases) decreases in the fair value of the contingent payments related to the Company’s VIEs were as follows: 2017 2016 2015 (in thousands) Parion $ 63,460 $ (64,800 ) $ (3,660 ) BioAxone (900 ) 9,950 (870 ) The fair value of the contingent payments related to the Parion Agreement and the BioAxone Agreement as of the dates set forth in the table were as follows: December 31, 2017 December 31, 2016 (in thousands) Parion $ — $ 238,800 BioAxone 18,900 18,000 The following table summarizes items related to the Company’s VIEs included in the Company’s consolidated balance sheets as of the dates set forth in the table. Amounts as of December 31, 2017 related to BioAxone while amounts as of December 31, 2016 related to Parion and BioAxone. December 31, 2017 December 31, 2016 (in thousands) Restricted cash and cash equivalents (VIE) $ 1,489 $ 47,762 Prepaid expenses and other current assets 22 6,812 Intangible assets 29,000 284,340 Other assets 256 399 Accounts payable 1,021 415 Taxes payable 2,171 1,330 Other current liabilities — 2,137 Deferred tax liability, net 4,756 131,446 Other liabilities — 300 Noncontrolling interest 13,727 181,609 The Company has recorded the VIEs’ cash and cash equivalents as “Restricted cash and cash equivalents (VIE)” because (i) the Company does not have any interest in or control over the VIEs’ cash and cash equivalents and (ii) the Company’s agreements with each VIE do not provide for the VIEs’ cash and cash equivalents to be used for the development of the assets that the Company licensed from the applicable VIE. Assets recorded as a result of consolidating the Company’s VIEs’ financial condition into the Company’s balance sheets do not represent additional assets that could be used to satisfy claims against the Company’s general assets. Other Collaborations The Company has entered into various agreements pursuant to which it collaborates with third parties, including inlicensing and outlicensing arrangements. Although the Company does not consider any of these arrangements to be material, the most notable of these arrangements are described below. Moderna Therapeutics, Inc. In July 2016, the Company entered into a strategic collaboration and licensing agreement (the "Moderna Agreement") with Moderna Therapeutics, Inc. ("Moderna"), pursuant to which the parties are seeking to identify and develop messenger Ribonucleic Acid ("mRNA") therapeutics for the treatment of CF. In connection with the Moderna Agreement, in the third quarter of 2016, the Company made an upfront payment to Moderna of $20.0 million and a $20.0 million cost-method investment in Moderna pursuant to a convertible promissory note that converted into preferred stock in August 2016. Moderna has the potential to receive future development and regulatory milestones of up to $275.0 million , including $220.0 million in approval and reimbursement milestones, as well as tiered royalty payments on future sales. Under the terms of the Moderna Agreement, Moderna will lead discovery efforts and the Company will lead all preclinical, development and commercialization activities associated with the advancement of mRNA Therapeutics that result from this collaboration and will fund all expenses related to the collaboration. The Company may terminate the Moderna Agreement by providing advance notice to Moderna, with the required length of notice dependent on whether any product developed under the Moderna Agreement has received marketing approval. The Moderna Agreement also may be terminated by either party for a material breach by the other, subject to notice and cure provisions. Unless earlier terminated, the Moderna Agreement will continue in effect until the expiration of the Company’s payment obligations under the Moderna Agreement. The Company evaluates the carrying value of its $20.0 million cost-method investment in Moderna, which is not a publicly traded company, for impairment on a quarterly basis and has not recorded any adjustments to the carrying value of its investment to date. Janssen Pharmaceuticals, Inc. In 2014, the Company entered into an agreement (the “Janssen Influenza Agreement”) with Janssen Pharmaceuticals, Inc. (“Janssen Inc.”). Pursuant to the agreement, Janssen Inc. has an exclusive worldwide license to develop and commercialize certain drug candidates for the treatment of influenza, including JNJ-63623872 (formerly VX-787). The Company received non-refundable payments of $35.0 million from Janssen Inc. in 2014, which were recorded as collaborative revenues. In the fourth quarter of 2017, the Company recognized $25.0 million in collaborative revenues due to a milestone that was achieved based on the Phase 3 clinical trial Janssen initiated in the fourth quarter of 2017. The Company has the potential to receive additional regulatory and commercial milestone payments as well as royalties on future product sales, if any. Janssen Inc. is responsible for costs related to the development and commercialization of the compounds. The Company recorded reimbursement for development activities conducted by the Company on behalf of Janssen of $2.0 million , $14.7 million and $22.8 million in 2017 , 2016 and 2015 , respectively. The reimbursements are recorded as a reduction to development expense in the Company’s consolidated statements of operations primarily due to the fact that Janssen Inc. directs the activities and selects the suppliers associated with these activities. Janssen Inc. may terminate the Janssen Influenza Agreement, subject to certain exceptions, upon six months’ notice. Asset Acquisition Concert Pharmaceuticals In July 2017, the Company acquired certain CF assets including VX-561 (formerly CTP-656) (the “Concert Assets”) from Concert Pharmaceuticals Inc. (“Concert”) pursuant to an asset purchase agreement that was entered into in March 2017 (the “Concert Agreement”). VX-561 is an investigational CFTR potentiator that has the potential to be used as part of combination regimens of CFTR modulators to treat CF. Pursuant to the Concert Agreement, Vertex paid Concert $160.0 million in cash for the Concert Assets. If VX-561 is approved as part of a combination regimen to treat CF, Concert would receive up to an additional $90.0 million in milestones based on regulatory approval in the U.S. and reimbursement in the UK, Germany or France. The Company determined that substantially all of the fair value of the Concert Agreement was attributable to a single in-process research and development asset, VX-561, which did not constitute a business. The Company concluded that it did not have any alternative future use for the acquired in-process research and development asset. Thus, the Company recorded the $160.0 million upfront payment as a research and development expense in 2017. The total cost of the transaction was $165.1 million including $5.1 million of transaction costs that were recorded as sales, general and administrative expenses. If the Company achieves regulatory approval and reimbursement milestones, the Company will record the value of the milestone as an intangible asset and will begin amortizing the asset in cost of product revenues in the period that the relevant milestone is achieved.

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share Basic net income (loss) per share attributable to Vertex common shareholders is based upon the weighted-average number of common shares outstanding during the period, excluding restricted stock, restricted stock units and performance-based restricted stock units, or PSUs, that have been issued but are not yet vested. Diluted net income (loss) per share attributable to Vertex common shareholders is based upon the weighted-average number of common shares outstanding during the period plus additional weighted-average common equivalent shares outstanding during the period when the effect is dilutive. The following table sets forth the computation of basic and diluted net income (loss) per share for three years ended December 31, 2017 : 2017 2016 2015 (in thousands, except per share amounts) Basic net income (loss) attributable to Vertex per common share calculation: Net income (loss) attributable to Vertex common shareholders $ 263,484 $ (112,052 ) $ (556,334 ) Less: Undistributed earnings allocated to participating securities (293 ) — — Net income (loss) attributable to Vertex common shareholders—basic $ 263,191 $ (112,052 ) $ (556,334 ) Basic weighted-average common shares outstanding 248,858 244,685 241,312 Basic net income (loss) attributable to Vertex per common share $ 1.06 $ (0.46 ) $ (2.31 ) Diluted net income (loss) attributable to Vertex per common share calculation: Net income (loss) attributable to Vertex common shareholders $ 263,484 $ (112,052 ) $ (556,334 ) Less: Undistributed earnings allocated to participating securities (288 ) — — Net income (loss) attributable to Vertex common shareholders—diluted $ 263,196 $ (112,052 ) $ (556,334 ) Weighted-average shares used to compute basic net income (loss) per common share 248,858 244,685 241,312 Effect of potentially dilutive securities: Stock options 2,797 — — Restricted stock and restricted stock units (including PSUs) 1,542 — — Employee stock purchase plan 28 — — Weighted-average shares used to compute diluted net income (loss) per common share 253,225 244,685 241,312 Diluted net income (loss) attributable to Vertex per common share $ 1.04 $ (0.46 ) $ (2.31 ) The Company did not include the securities in the following table in the computation of the net income (loss) per share attributable to Vertex common shareholders calculations because the effect would have been anti-dilutive during each period. 2017 2016 2015 (in thousands) Stock options 3,554 12,642 11,145 Unvested restricted stock and restricted stock units (including PSUs) 411 3,546 3,024

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The fair value of the Company’s financial assets and liabilities reflects the Company’s estimate of amounts that it would have received in connection with the sale of the assets or paid in connection with the transfer of the liabilities in an orderly transaction between market participants at the measurement date. In connection with measuring the fair value of its assets and liabilities, the Company seeks to maximize the use of observable inputs (market data obtained from sources independent from the Company) and to minimize the use of unobservable inputs (the Company’s assumptions about how market participants would price assets and liabilities). The following fair value hierarchy is used to classify assets and liabilities based on the observable inputs and unobservable inputs used in order to value the assets and liabilities: Level 1: Quoted prices in active markets for identical assets or liabilities. An active market for an asset or liability is a market in which transactions for the asset or liability occur with sufficient frequency and volume to provide pricing information on an ongoing basis. Level 2: Observable inputs other than Level 1 inputs. Examples of Level 2 inputs include quoted prices in active markets for similar assets or liabilities and quoted prices for identical assets or liabilities in markets that are not active. Level 3: Unobservable inputs based on the Company’s assessment of the assumptions that market participants would use in pricing the asset or liability. The Company’s investment strategy is focused on capital preservation. The Company invests in instruments that meet the credit quality standards outlined in the Company’s investment policy. This policy also limits the amount of credit exposure to any one issue or type of instrument. As of December 31, 2017 , the Company’s investments were primarily in money market funds, government-sponsored enterprise securities, corporate equity securities, corporate debt securities and commercial paper . Additionally, the Company utilizes foreign currency forward contracts intended to mitigate the effect of changes in foreign exchange rates on its consolidated statement of operations. As of December 31, 2017 , all of the Company’s financial assets and liabilities that were subject to fair value measurements were valued using observable inputs. The Company’s financial assets valued based on Level 1 inputs consisted of money market funds, government-sponsored enterprise securities and corporate equity securities. The Company’s financial assets and liabilities valued based on Level 2 inputs consisted of corporate debt securities and commercial paper, which consisted of investments in highly-rated investment-grade corporations and foreign currency forward contracts with highly reputable and creditworthy counterparties. During 2017 , 2016 and 2015 , the Company did not record an other-than-temporary impairment charge related to its financial assets. The following table sets forth the Company’s financial assets and liabilities (excluding VIE cash and cash equivalents) subject to fair value measurements: Fair Value Measurements as Fair Value Hierarchy Total Level 1 Level 2 Level 3 (in thousands) Financial instruments carried at fair value (asset position): Cash equivalents: Money market funds $ 614,951 $ 614,951 $ — $ — Government-sponsored enterprise securities 12,678 12,678 — — Commercial paper 57,357 — 57,357 — Marketable securities: Corporate equity securities 74,821 74,821 — — Government-sponsored enterprise securities 2,303 2,303 — — Corporate debt securities 265,867 — 265,867 — Commercial paper 80,263 — 80,263 — Prepaid and other current assets: Foreign currency forward contracts 13 — 13 — Total financial assets $ 1,108,253 $ 704,753 $ 403,500 $ — Financial instruments carried at fair value (liability position): Other liabilities, current portion: Foreign currency forward contracts $ (13,642 ) $ — $ (13,642 ) $ — Other liabilities, excluding current portion: Foreign currency forward contracts (866 ) — (866 ) — Total financial liabilities $ (14,508 ) $ — $ (14,508 ) $ — Fair Value Measurements as Fair Value Hierarchy Total Level 1 Level 2 Level 3 (in thousands) Financial instruments carried at fair value (asset position): Cash equivalents: Money market funds $ 280,560 $ 280,560 $ — $ — Marketable securities: Corporate equity securities 64,560 64,560 — — Government-sponsored enterprise securities 15,508 15,508 — — Corporate debt securities 111,140 — 111,140 — Commercial paper 59,404 — 59,404 — Prepaid and other current assets: Foreign currency forward contracts 14,407 — 14,407 — Other assets: Foreign currency forward contracts 1,186 — 1,186 — Total financial assets $ 546,765 $ 360,628 $ 186,137 $ — Financial instruments carried at fair value (liability position): Other liabilities, current portion: Foreign currency forward contracts $ (144 ) $ — $ (144 ) $ — Total financial liabilities $ (144 ) $ — $ (144 ) $ — The Company’s VIE invested in cash equivalents consisting of money market funds of $1.5 million as of December 31, 2017 , which are valued based on Level 1 inputs. These cash equivalents are not included in the table above. The Company’s noncontrolling interest related to the Company’s VIE includes the fair value of the contingent payments, which consist of milestone, royalty and option payments, which are valued based on Level 3 inputs. Please refer to Note B, “ Collaborative Arrangements and Acquisitions, ” for further information.

Marketable Securities

Marketable Securities	12 Months Ended
	Dec. 31, 2017
Cash and Cash Equivalents [Abstract]
Marketable Securities	Marketable Securities A summary of the Company’s cash, cash equivalents and marketable securities is shown below: Amortized Cost Gross Gross Fair Value (in thousands) December 31, 2017 Cash and cash equivalents: Cash and money market funds $ 1,595,377 $ — $ — $ 1,595,377 Government-sponsored enterprise securities 12,679 — (1 ) 12,678 Commercial paper 57,371 — (14 ) 57,357 Total cash and cash equivalents $ 1,665,427 $ — $ (15 ) $ 1,665,412 Marketable securities: Corporate equity securities $ 43,213 $ 31,608 $ — $ 74,821 Government-sponsored enterprise securities 2,304 — (1 ) 2,303 Corporate debt securities (matures within 1 year) 215,639 — (363 ) 215,276 Corporate debt securities (matures after 1 year through 5 years) 50,697 — (106 ) 50,591 Commercial paper (matures within 1 year) 80,372 — (109 ) 80,263 Total marketable securities 392,225 31,608 (579 ) 423,254 Total cash, cash equivalents and marketable securities $ 2,057,652 $ 31,608 $ (594 ) $ 2,088,666 December 31, 2016 Cash and cash equivalents: Cash and money market funds $ 1,183,945 $ — $ — $ 1,183,945 Total cash and cash equivalents $ 1,183,945 $ — $ — $ 1,183,945 Marketable securities: Corporate equity securities $ 43,213 $ 21,347 $ — $ 64,560 Government-sponsored enterprise securities (matures within 1 year) 15,506 2 — 15,508 Corporate debt securities (matures within 1 year) 111,225 — (85 ) 111,140 Commercial paper (matures within 1 year) 59,331 73 — 59,404 Total marketable securities 229,275 21,422 (85 ) 250,612 Total cash, cash equivalents and marketable securities $ 1,413,220 $ 21,422 $ (85 ) $ 1,434,557 The Company has a limited number of marketable securities in insignificant loss positions as of December 31, 2017 , which the Company does not intend to sell and has concluded it will not be required to sell before recovery of the amortized costs for the investments at maturity. There were no charges recorded for other-than-temporary declines in fair value of marketable securities nor gross realized gains or losses recognized in 2017 , 2016 or 2015 .

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) The following table summarizes the changes in accumulated other comprehensive income (loss) by component: Foreign currency translation adjustment Unrealized holding gains (losses) on marketable securities, net of tax Unrealized (losses) gains on foreign currency forward contracts, net of tax Total (in thousands) Balance at December 31, 2014 $ (971 ) $ (123 ) $ 2,011 $ 917 Other comprehensive (loss) income before reclassifications (1,109 ) 249 6,493 5,633 Amounts reclassified from accumulated other comprehensive income (loss) — — (4,726 ) (4,726 ) Net current period other comprehensive (loss) income (1,109 ) 249 1,767 907 Balance at December 31, 2015 $ (2,080 ) $ 126 $ 3,778 $ 1,824 Other comprehensive (loss) income before reclassifications (5,782 ) 17,395 17,383 28,996 Amounts reclassified from accumulated other comprehensive income (loss) — — (9,647 ) (9,647 ) Net current period other comprehensive (loss) income (5,782 ) 17,395 7,736 19,349 Balance at December 31, 2016 $ (7,862 ) $ 17,521 $ 11,514 $ 21,173 Other comprehensive (loss) income before reclassifications (13,169 ) 6,954 (29,175 ) (35,390 ) Amounts reclassified from accumulated other comprehensive income (loss) — — 2,645 2,645 Net current period other comprehensive (loss) income (13,169 ) 6,954 (26,530 ) (32,745 ) Balance at December 31, 2017 $ (21,031 ) $ 24,475 $ (15,016 ) $ (11,572 )

Hedging

Hedging	12 Months Ended
	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Hedging	Hedging The Company maintains a hedging program intended to mitigate the effect of changes in foreign exchange rates for a portion of the Company’s forecasted product revenues denominated in certain foreign currencies. The program includes foreign currency forward contracts that are designated as cash flow hedges under GAAP having contractual durations from one to eighteen months. The Company formally documents the relationship between foreign currency forward contracts (hedging instruments) and forecasted product revenues (hedged items), as well as the Company’s risk management objective and strategy for undertaking various hedging activities, which includes matching all foreign currency forward contracts that are designated as cash flow hedges to forecasted transactions. The Company also formally assesses, both at the hedge’s inception and on an ongoing basis, whether the foreign currency forward contracts are highly effective in offsetting changes in cash flows of hedged items on a prospective and retrospective basis. If the Company determines that a (i) foreign currency forward contract is not highly effective as a cash flow hedge, (ii) foreign currency forward contract has ceased to be a highly effective hedge or (iii) forecasted transaction is no longer probable of occurring, the Company would discontinue hedge accounting treatment prospectively. The Company measures effectiveness based on the change in fair value of the forward contracts and the fair value of the hypothetical foreign currency forward contracts with terms that match the critical terms of the risk being hedged. As of December 31, 2017 , all hedges were determined to be highly effective and the Company had not recorded any ineffectiveness related to the hedging program. The following table summarizes the notional amount of the Company’s outstanding foreign currency forward contracts designated as cash flow hedges: As of As of December 31, 2017 2016 Foreign Currency (in thousands) Euro $ 257,230 $ 164,368 British pound sterling 77,481 65,237 Australian dollar 30,501 23,776 Total foreign currency forward contracts $ 365,212 $ 253,381 The following table summarizes the fair value of the Company’s outstanding foreign currency forward contracts designated as cash flow hedges under GAAP included on the Company’s consolidated balance sheets: As of December 31, 2017 Assets Liabilities Classification Fair Value Classification Fair Value (in thousands) Prepaid and other current assets $ 13 Other liabilities, current portion $ (13,642 ) Other assets — Other liabilities, excluding current portion (866 ) Total assets $ 13 Total liabilities $ (14,508 ) As of December 31, 2016 Assets Liabilities Classification Fair Value Classification Fair Value (in thousands) Prepaid and other current assets $ 14,407 Other liabilities, current portion $ (144 ) Other assets 1,186 Other liabilities, excluding current portion — Total assets $ 15,593 Total liabilities $ (144 ) The following table summarizes the potential effect of offsetting derivatives by type of financial instrument on the Company’s consolidated balance sheets: As of December 31, 2017 Gross Amounts Recognized Gross Amounts Offset Gross Amount Presented Gross Amount Not Offset Legal Offset Foreign currency forward contracts (in thousands) Total assets $ 13 $ — $ 13 $ (13 ) $ — Total liabilities (14,508 ) — (14,508 ) 13 (14,495 ) As of December 31, 2016 Gross Amounts Recognized Gross Amounts Offset Gross Amount Presented Gross Amount Not Offset Legal Offset Foreign currency forward contracts (in thousands) Total assets $ 15,593 $ — $ 15,593 $ (144 ) $ 15,449 Total liabilities (144 ) — (144 ) 144 — In 2016, Company began entering into foreign exchange forward contracts with contractual maturities of less than one month designed to mitigate the effect of changes in foreign exchange rates on monetary assets and liabilities including intercompany balances. The Company recognized a loss of $14.1 million and a gain of $6.9 million , recorded in other income (expense), net, during 2017 and 2016 , respectively, related to foreign exchange contracts, which are not designated as hedging instruments under GAAP. As of December 31, 2017 , the notional amount of foreign exchange contracts where hedge accounting under GAAP is not applied was $122.8 million . The following table summarizes the fair value of the Company’s outstanding foreign currency forward contracts not designated for hedge accounting under GAAP included on the Company’s consolidated balance sheets: As of December 31, 2017 2016 (in thousands) Prepaid expenses and other current assets $ — $ 660 Other liabilities, current portion 684 —

Inventories

Inventories	12 Months Ended
	Dec. 31, 2017
Inventory Disclosure [Abstract]
Inventories	Inventories Inventories consisted of the following: As of December 31, 2017 2016 (in thousands) Raw materials $ 20,924 $ 6,348 Work-in-process 74,237 56,672 Finished goods 16,669 14,584 Total $ 111,830 $ 77,604

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Property and Equipment	Property and Equipment Property and equipment, net consisted of the following: As of December 31, 2017 2016 (in thousands) Buildings $ 634,061 $ 548,232 Furniture and equipment 256,509 236,634 Software 151,890 134,321 Leasehold improvements 117,806 108,702 Computers 61,294 58,271 Total property and equipment, gross 1,221,560 1,086,160 Less: accumulated depreciation (432,123 ) (387,798 ) Total property and equipment, net $ 789,437 $ 698,362 Total property and equipment, gross, as of December 31, 2017 and 2016 , included $100.9 million and $101.3 million , respectively, for property and equipment recorded under capital leases. Accumulated depreciation, as of December 31, 2017 and 2016 , included $43.4 million and $37.9 million , respectively, for property and equipment recorded under capital leases. Total property and equipment, gross, as of December 31, 2017 and 2016 , included $21.1 million and $17.8 million , respectively, for capitalized internally developed software. Accumulated depreciation, as of December 31, 2017 and 2016 , included $13.0 million and $9.2 million , respectively, for capitalized internally developed software. The Company recorded depreciation expense of $61.4 million , $60.8 million and $60.0 million in 2017 , 2016 and 2015 , respectively.

Intangible Assets and Goodwill

Intangible Assets and Goodwill	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets and Goodwill	Intangible Assets and Goodwill Intangible Assets As of December 31, 2017 and December 31, 2016 , in-process research and development intangible assets of $29.0 million and $284.3 million , respectively, were recorded on the Company’s consolidated balance sheet. In 2015, the Company recorded an in-process research development intangible asset of $255.3 million related to Parion’s pulmonary ENaC platform, including the intellectual property related to VX-371 and VX-551, that are licensed by Parion to the Company. In 2014, the Company recorded an in-process research and development intangible asset of $29.0 million related to VX-210 that is licensed by BioAxone to the Company. In connection with its preparation of its financial statements for September 30, 2017, the Company determined that there were indicators that the value of the pulmonary ENaC platform intangible asset had become impaired. The Company determined that the fair value of the intangible asset had decreased significantly based on data received in September 2017 from a Phase 2 clinical trial of VX-371 that did not meet its primary efficacy endpoint. Based on this data, the Company evaluated the fair value of Parion’s pulmonary ENaC platform using the discounted cash flow approach from the perspective of a market participant and determined that the fair value of the intangible asset was zero as of September 30, 2017. The discounted cash flow model pertaining to the impairment of the pulmonary ENaC platform includes (i) assumptions regarding the probability of obtaining marketing approval for the drug candidate, (ii) estimates regarding the timing of and the expected costs to develop and commercialize the drug candidate, (iii) estimates of future cash flows from potential product sales with respect to the drug candidate and (iv) appropriate discount and tax rates. The Company recorded a $255.3 million impairment charge and a benefit from income taxes of $97.7 million in 2017 attributable to noncontrolling interest. Goodwill As of each of December 31, 2017 and December 31, 2016 , goodwill of $50.4 million was recorded on the Company’s consolidated balance sheet.

Additional Balance Sheet Detail

Additional Balance Sheet Detail	12 Months Ended
	Dec. 31, 2017
Payables and Accruals [Abstract]
Additional Balance Sheet Detail	Additional Balance Sheet Detail Prepaid and other current assets consisted of the following: As of December 31, 2017 2016 (in thousands) Prepaid expenses $ 62,475 $ 36,134 Collaborative accounts receivable 28,907 719 Other receivables and assets 74,253 34,400 Total $ 165,635 $ 71,253 Accrued expenses consisted of the following: As of December 31, 2017 2016 (in thousands) Payroll and benefits $ 113,026 $ 86,387 Research, development and commercial contract costs 98,411 62,756 Product revenue allowances 119,919 86,533 Royalty payable 73,044 52,845 Other 39,561 26,728 Total $ 443,961 $ 315,249

Long Term Obligations

Long Term Obligations	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Long Term Obligations	Long Term Obligations Fan Pier Leases In 2011, the Company entered into two lease agreements, pursuant to which the Company leases approximately 1.1 million square feet of office and laboratory space in two buildings (the “Buildings”) at Fan Pier in Boston, Massachusetts (the “Fan Pier Leases”). The Company commenced lease payments in December 2013, and will make lease payments pursuant to the Fan Pier Leases through December 2028. The Company has an option to extend the term of the Fan Pier Leases for an additional 10 years. Because the Company was involved in the construction project, the Company was deemed for accounting purposes to be the owner of the Buildings during the construction period and recorded project construction costs incurred by the landlord. Upon completion of the Buildings, the Company evaluated the Fan Pier Leases and determined that the Fan Pier Leases did not meet the criteria for “sale-leaseback” treatment. Accordingly, the Company began depreciating the asset and incurring interest expense related to the financing obligation in 2013. The Company bifurcates its lease payments pursuant to the Fan Pier Leases into (i) a portion that is allocated to the Buildings and (ii) a portion that is allocated to the land on which the Buildings were constructed. The portion of the lease obligations allocated to the land is treated as an operating lease that commenced in 2011. The Company recorded interest expense of $60.1 million in 2017 and $60.2 million in each of 2016 and 2015 . The Company recorded depreciation expense of $13.3 million in each of 2017 , 2016 and 2015 . In each of 2017 , 2016 and 2015 , the Company recorded rent expense of $6.5 million . Property and equipment, net, included $475.7 million and $489.0 million as of December 31, 2017 and 2016 , respectively, related to construction costs for the Buildings. The carrying value of the construction financing lease obligation related to the Buildings, which excludes interest that will be imputed over the course of the Company’s lease agreement for the Buildings, was $472.1 million and $472.6 million , as of December 31, 2017 and 2016 , respectively. San Diego Lease On December 2, 2015, the Company entered into a lease agreement for 3215 Merryfield Row, San Diego, California with ARE-SD Region No. 23, LLC. Pursuant to this agreement, the Company agreed to lease approximately 170,000 square feet of office and laboratory space in a building under construction in San Diego, California (“San Diego Lease”) for a term of 16 years . The Company expects base rent payments will commence in the second quarter of 2019. Pursuant to the San Diego Lease, during the initial 16 -year term, the Company will pay an average of approximately $10.2 million per year in aggregate rent, exclusive of operating expenses. The Company has the option to extend the lease term for up to two additional five -year terms. Because the Company is involved in the construction project, the Company is deemed for accounting purposes to be the owner of the San Diego building during the construction period and recorded project construction costs incurred by the landlord. The Company bifurcates its lease payments pursuant to the San Diego Lease into (i) a portion that is allocated to the San Diego building and (ii) a portion that is allocated to the land on which the San Diego building was constructed. Although the Company will not begin making lease payments pursuant to the San Diego Lease until the commencement date, the portion of the lease obligation allocated to the land is treated for accounting purposes as an operating lease that commenced in the fourth quarter of 2016. Upon completion of the San Diego building, the Company will evaluate the San Diego Lease and determine if the San Diego Lease meets the criteria for “sale-leaseback” treatment. If the San Diego Lease meets the “sale-leaseback” criteria, the Company will remove the asset and the related liability from its consolidated balance sheet and treat the San Diego Lease as either an operating or a capital lease based on the Company’s assessment of the accounting guidance. The Company expects that upon completion of construction of the San Diego building the San Diego Lease will not meet the “sale-leaseback” criteria. If the San Diego Lease does not meet “sale-leaseback” criteria, the Company will treat the San Diego Lease as a financing obligation and will depreciate the asset over its estimated useful life. Property and equipment, net, included $94.6 million and $15.0 million as of December 31, 2017 and 2016 , respectively, related to construction costs for the San Diego building. The carrying value of the construction financing lease obligation for the San Diego building was $87.4 million and $12.6 million as of December 31, 2017 and 2016 , respectively. Revolving Credit Facility In October 2016, the Company entered into a Credit Agreement (the “Credit Agreement”) with Bank of America, N.A., as administrative agent and the lenders referred to therein. The Credit Agreement provides for a $500.0 million revolving facility, $300.0 million of which was drawn at closing (the “Loans”) and was repaid in February 2017. The Credit Agreement also provides that, subject to satisfaction of certain conditions, the Company may request that the borrowing capacity under the Credit Agreement be increased by an additional $300.0 million . The Credit Agreement matures on October 13, 2021. The proceeds of the borrowing under the Credit Agreement were used primarily to repay the Company's existing indebtedness under the Macquarie Loan. The Loans will bear interest, at the Company's option, at either a base rate or a Eurodollar rate, in each case plus an applicable margin. Under the Credit Agreement, the applicable margins on base rate loans range from 0.75% to 1.50% and the applicable margins on Eurodollar loans range from 1.75% to 2.50% , in each case based on the Company's consolidated leverage ratio (the ratio of the Company's total consolidated debt to the Company's trailing twelve-month EBITDA). The Loans are guaranteed by certain of the Company's domestic subsidiaries and secured by substantially all of the Company's assets and the assets of the Company's domestic subsidiaries (excluding intellectual property, owned and leased real property and certain other excluded property) and by the equity interests of the Company's subsidiaries, subject to certain exceptions. Under the terms of the Credit Agreement, the Company must maintain, subject to certain limited exceptions, a consolidated leverage ratio of 3.00 to 1.00 and consolidated EBITDA of at least $200.0 million , in each case to be measured on a quarterly basis. The Credit Agreement contains customary representations and warranties and usual and customary affirmative and negative covenants. The Credit Agreement also contains customary events of default. In the case of a continuing event of default, the administrative agent would be entitled to exercise various remedies, including the acceleration of amounts due under outstanding loans. Term Loan In 2014, the Company entered into a credit agreement with the lenders party thereto, and Macquarie US Trading LLC (“Macquarie”), as administrative agent. The credit agreement provided for a $300.0 million senior secured term loan (“Macquarie Loan”). On October 13, 2016, the Company terminated and repaid all outstanding obligations under the Macquarie Loan. The Company incurred a charge of $2.2 million in the fourth quarter of 2016 related to a loss on extinguishment attributable to the Macquarie Loan that was recorded as “Interest expense, net” in the Company’s consolidated statements of operations. The Macquarie Loan initially bore interest at a rate of 7.2% per annum, which was reduced to 6.2% per annum based on the FDA’s approval of ORKAMBI and was reduced to a rate of LIBOR plus 5.0% per annum during the third year of the term. The Company incurred $5.3 million in fees paid to Macquarie that were recorded as a discount on the term loan and that were recorded as additional interest expense using the effective interest method over the term of the loan in the Company’s consolidated statements of operations.

Common Stock, Preferred Stock a

Common Stock, Preferred Stock and Equity Plans	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Common Stock, Preferred Stock and Equity Plans	Common Stock, Preferred Stock and Equity Plans The Company is authorized to issue 500,000,000 shares of common stock. Holders of common stock are entitled to one vote per share. Holders of common stock are entitled to receive dividends, if and when declared by the Company’s Board of Directors, and to share ratably in the Company’s assets legally available for distribution to the Company’s shareholders in the event of liquidation. Holders of common stock have no preemptive, subscription, redemption or conversion rights. The holders of common stock do not have cumulative voting rights. The Company is authorized to issue 1,000,000 shares of preferred stock in one or more series and to fix the powers, designations, preferences and relative participating, option or other rights thereof, including dividend rights, conversion rights, voting rights, redemption terms, liquidation preferences and the number of shares constituting any series, without any further vote or action by the Company’s shareholders. As of December 31, 2017 and 2016 , the Company had no shares of preferred stock issued or outstanding. Stock and Option Plans The purpose of each of the Company’s stock and option plans is to attract, retain and motivate its employees, consultants and directors. Awards granted under these plans can be incentive stock options (“ISOs”), nonstatutory stock options (“NSOs”), restricted stock (“RSs”), restricted stock units (“RSUs”) including performance-based RSUs (“PSUs”) or other equity-based awards, as specified in the individual plans. Shares issued under all of the Company’s plans are funded through the issuance of new shares. The following table contains information about the Company’s equity plans: As of December 31, 2017 Title of Plan Group Eligible Type of Award Awards Additional Awards 2013 Stock and Option Plan Employees, Non-employee Directors and Consultants NSO, 10,388,723 11,427,114 2006 Stock and Option Plan Employees, Non-employee Directors and Consultants NSO, 3,102,768 — Total 13,491,491 11,427,114 All options granted under the Company’s 2013 Stock and Option Plan (“2013 Plan”) and 2006 Stock and Option Plan (“2006 Plan”) were granted with an exercise price equal to the fair value of the underlying common stock on the date of grant. As of December 31, 2017 , the stock and option plan under which the Company is authorized to make new equity awards is the Company’s 2013 Plan. Under the 2013 Plan, no stock options can be awarded with an exercise price less than the fair market value on the date of grant. In the three years ended December 31, 2017 , the Company’s shareholders approved increases in the number of shares authorized for issuance pursuant to the 2013 Stock and Option Plan of (i) 6,750,000 shares in 2017, and (ii) 7,800,000 shares in 2015, plus the number of shares that remained available for issuance under the Company’s 2006 Stock and Option Plan, which rolled-over into the 2013 Stock and Option Plan in 2015. During the three years ended December 31, 2017 , grants to current employees and directors primarily had a grant date that was the same as the date the award was approved by the Company’s Board of Directors. During the three years ended December 31, 2017 , for grants to new employees and directors, the date of grant for awards was the employee’s first day of employment or the date the director was elected to the Company’s Board of Directors. All options awarded under the Company’s stock and option plans expire not more than 10 years from the grant date. Stock Options The following table summarizes information related to the outstanding and exercisable options during the year ended December 31, 2017 : Stock Options Weighted-average Weighted-average Aggregate Intrinsic (in thousands) (per share) (in years) (in thousands) Outstanding at December 31, 2016 12,642 $ 81.41 Granted 2,359 $ 108.43 Exercised (4,561 ) $ 70.90 Forfeited (611 ) $ 99.53 Expired (62 ) $ 105.24 Outstanding at December 31, 2017 9,767 $ 91.57 6.95 $ 585,293 Exercisable at December 31, 2017 5,313 $ 80.14 5.75 $ 375,472 The aggregate intrinsic value in the table above represents the total pre-tax amount, net of exercise price, that would have been received by option holders if all option holders had exercised all options with an exercise price lower than the market price on the last business day of 2017 , which was $150.71 based on the average of the high and low price of the Company’s common stock on that date. The total intrinsic value (the amount by which the fair market value exceeded the exercise price) of stock options exercised during 2017 , 2016 and 2015 was $302.8 million , $48.6 million and $252.9 million , respectively. The total cash received by the Company as a result of employee stock option exercises during 2017 , 2016 and 2015 was $323.3 million , $48.5 million and $165.6 million , respectively. The following table summarizes information about stock options outstanding and exercisable at December 31, 2017 : Options Outstanding Options Exercisable Range of Exercise Prices Number Weighted-average Weighted-average Number Weighted-average (in thousands) (in years) (per share) (in thousands) (per share) $18.93–$20.00 128 0.10 $ 18.93 128 $ 18.93 $20.01–$40.00 810 1.88 $ 34.43 810 $ 34.43 $40.01–$60.00 798 4.49 $ 49.15 798 $ 49.15 $60.01–$80.00 746 6.19 $ 75.49 653 $ 75.40 $80.01–$100.00 4,350 8.07 $ 89.31 1,514 $ 89.51 $100.01–$120.00 1,087 7.11 $ 109.34 633 $ 109.24 $120.01–$140.00 1,223 7.63 $ 130.20 734 $ 129.89 $140.01–$160.00 — — $ — — $ — $160.01–$163.74 625 9.54 $ 162.94 43 $ 162.94 Total 9,767 6.95 $ 91.57 5,313 $ 80.14 Restricted Stock and Restricted Stock Units (excluding PSUs) The following table summarizes the restricted stock and restricted stock unit activity of the Company during the year ended December 31, 2017 : Restricted Stock Restricted Stock Units (excluding PSUs) Number of Units Weighted-average Number of Shares Weighted-average (in thousands) (per share) (in thousands) (per share) Unvested at December 31, 2016 2,613 $ 102.54 798 $ 92.62 Granted — $ — 1,719 $ 113.13 Vested (1,206 ) $ 102.99 (278 ) $ 94.72 Cancelled (178 ) $ 102.45 (228 ) $ 97.86 Unvested at December 31, 2017 1,229 $ 102.12 2,011 $ 109.27 The total fair value of restricted stock that vested during 2017 , 2016 and 2015 (measured on the date of vesting) was $157.0 million , $74.1 million and $124.0 million , respectively. The total fair value of restricted stock units that vested during 2017 , 2016 and 2015 (measured on the date of vesting) was $33.2 million , $5.3 million and $8.0 million , respectively. Performance-based RSUs (PSUs) The potential range of shares issuable pursuant to the Company’s PSU awards range from 0% to 200% of the target shares based on financial and non-financial measures. Fifty percent of PSUs that could be earned have a one -year performance period with the amount actually earned dependent upon the Company’s product revenue performance and with vesting of the earned shares in three equal installments over a three -year period. The remaining 50% of PSUs that could be earned have a three -year performance period with the amount actually earned dependent upon the achievement of multiple clinical development milestones and with the earned shares cliff vesting at the end of the three -year performance period. The following table summarizes the PSU activity of the Company during the year ended December 31, 2017 : Performance-Based RSU Number of Units Weighted-average (in thousands) (per share) Unvested at December 31, 2016 (1) 135 $ 91.05 Granted (2) 392 $ 86.71 Vested (15 ) $ 91.05 Cancelled (28 ) $ 86.52 Unvested at December 31, 2017 484 $ 87.59 (1) Represents the Company’s 2016 PSUs based on the target number of shares issuable at the end of each of the financial and non-financial performance periods. (2) Represents (i) the target number of shares issuable for the Company’s 2017 PSUs at the end of each of the financial and non-financial performance periods and (ii) a decrease in shares issuable under 2016 PSUs based on 2016 financial performance. The total fair value of PSUs that vested during 2017 (measured on the date of vesting) was $1.3 million . There were no PSUs that vested during 2016, which was the first year that the Company granted PSUs. Employee Stock Purchase Plan The Company has an employee stock purchase plan (the “ESPP”). The ESPP permits eligible employees to enroll in a twelve -month offering period comprising two six -month purchase periods. Participants may purchase shares of the Company’s common stock, through payroll deductions, at a price equal to 85% of the fair market value of the common stock on the first day of the applicable twelve -month offering period, or the last day of the applicable six -month purchase period, whichever is lower. Purchase dates under the ESPP occur on or about May 14 and November 14 of each year. As of December 31, 2017 , there were 616,256 shares of common stock authorized for issuance pursuant to the ESPP. In 2017 , the following shares were issued to employees under the ESPP: Year Ended December 31, 2017 (in thousands, Number of shares 275 Average price paid per share $ 80.71

Stock-based Compensation Expens

Stock-based Compensation Expense	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-based Compensation Expense	Stock-based Compensation Expense The Company recognizes share-based payments to employees as compensation expense using the fair value method. The fair value of stock options and shares purchased pursuant to the ESPP is calculated using the Black-Scholes option pricing model. The fair value of restricted stock and restricted stock units, including PSUs, is based on the intrinsic value on the date of grant. Stock-based compensation, measured at the grant date based on the fair value of the award, is typically recognized as expense ratably over the requisite service period. The expense recognized over the requisite service period is recorded net of the impact for actual awards that were forfeited prior to vesting in the year ended December 31, 2017 in accordance with new accounting guidance that became effective in 2017. Prior to adoption, the expense recognized included an estimate of awards that would be forfeited prior to vesting for the years ended December 31, 2016 and 2015 . The effect of stock-based compensation expense during the three years ended December 31, 2017 was as follows: 2017 2016 2015 (in thousands) Stock-based compensation expense by line item: Research and development expenses $ 181,900 $ 153,451 $ 152,955 Sales, general and administrative expenses 108,836 84,254 78,070 Total stock-based compensation expense included in costs and expenses $ 290,736 $ 237,705 $ 231,025 The stock-based compensation expense by type of award during the three years ended December 31, 2017 was as follows: 2017 2016 2015 (in thousands) Stock-based compensation expense by type of award: Stock options $ 105,367 $ 114,768 $ 129,276 Restricted stock and restricted stock units (including PSUs) 181,258 118,709 98,811 ESPP share issuances 9,017 7,835 7,025 Less: stock-based compensation expense capitalized to inventories (4,906 ) (3,607 ) (4,087 ) Total stock-based compensation expense included in costs and expenses $ 290,736 $ 237,705 $ 231,025 The Company capitalizes stock-based compensation expense to inventories, all of which is attributable to employees who support the Company’s manufacturing operations for the Company’s products. The following table sets forth the Company’s unrecognized stock-based compensation expense as of December 31, 2017 , by type of award and the weighted-average period over which that expense is expected to be recognized: As of December 31, 2017 Unrecognized Expense Weighted-average Recognition Period (in thousands) (in years) Type of award: Stock options $ 147,402 2.45 Restricted stock and restricted stock units (including PSUs) $ 254,302 2.47 ESPP share issuances $ 4,245 0.59 Stock Options The Company issues stock options with service conditions, which are generally the vesting periods of the awards. The Company uses the Black-Scholes option pricing model to estimate the fair value of stock options at the grant date. The Black-Scholes option pricing model uses the option exercise price as well as estimates and assumptions related to the expected price volatility of the Company’s stock, the rate of return on risk-free investments, the expected period during which the options will be outstanding, and the expected dividend yield for the Company’s stock to estimate the fair value of a stock option on the grant date. The options granted during 2017 , 2016 and 2015 had a weighted-average grant-date fair value per share of $43.27 , $37.93 and $52.16 , respectively. The fair value of each option granted during 2017 , 2016 and 2015 was estimated on the date of grant using the Black-Scholes option pricing model with the following weighted-average assumptions: 2017 2016 2015 Expected stock price volatility 45.31 % 46.77 % 47.29 % Risk-free interest rate 1.94 % 1.32 % 1.61 % Expected term of options (in years) 4.68 4.91 5.28 Expected annual dividends — — — The weighted-average valuation assumptions were determined as follows: • Expected stock price volatility: Expected stock price volatility is calculated using the trailing one month average of daily implied volatilities prior to the grant date. Implied volatility is based on options to purchase the Company’s stock with remaining terms of greater than one year that are regularly traded in the market. • Risk-free interest rate: The Company bases the risk-free interest rate on the interest rate payable on U.S. Treasury securities in effect at the time of grant for a period that is commensurate with the assumed expected option term. • Expected term of options: The expected term of options represents the period of time options are expected to be outstanding. The Company uses historical data to estimate employee exercise and post-vest termination behavior. The Company believes that all groups of employees exhibit similar exercise and post-vest termination behavior and therefore does not stratify employees into multiple groups in determining the expected term of options. • Expected annual dividends: The estimate for annual dividends is $0.00 because the Company has not historically paid, and does not intend for the foreseeable future to pay, a dividend. Restricted Stock, Restricted Stock Units and Performance-based Restricted Stock Units The Company awards restricted stock and restricted stock units with service conditions, which are generally the vesting periods of the awards. Prior to 2017, the Company also awarded, to certain members of senior management, on an annual basis restricted stock and restricted stock units that vest upon the earlier of the satisfaction of (i) a performance condition or (ii) a service condition. In February 2016, the Company began granting PSUs to certain members of senior management. Half of the PSUs contained financial goals as the performance metric and the other half contained non-financial goals. A target number of shares was established for each award, however the actual number of shares that will be issued when an award vests may range from zero to 200% of the target amount depending upon the level of achievement of the applicable performance metric. The financial-based PSUs vest in three equal installments over a three -year period and are expensed ratably over that same period based upon an assessment of the likely level of achievement. The non-financial based PSUs cliff vest at the end of the three -year performance period and are expensed on a straight-line basis over that same period based upon an assessment of the likely level of achievement. In addition, in 2015 and 2014, the Company issued, pursuant to a retention program, restricted stock awards to certain members of senior management that vested on various dates in the fourth quarter of 2017 and in January 2018 upon the satisfaction of both (i) a performance condition and (ii) a service condition. Employee Stock Purchase Plan The weighted-average fair value of each purchase right granted during 2017 , 2016 and 2015 was $35.90 , $26.86 and $37.84 , respectively. The following table reflects the weighted-average assumptions used in the Black-Scholes option pricing model for 2017 , 2016 and 2015 : 2017 2016 2015 Expected stock price volatility 39.09 % 48.22 % 47.20 % Risk-free interest rate 1.24 % 0.56 % 0.40 % Expected term (in years) 0.75 0.75 0.72 Expected annual dividends — — — The expected stock price volatility for ESPP offerings is based on implied volatility. The Company bases the risk-free interest rate on the interest rate payable on U.S. Treasury securities in effect at the time of grant for a period that is commensurate with the assumed expected term. The expected term represents purchases and purchase periods that take place within the offering period. The expected annual dividends estimate is $0.00 because the Company has not historically paid, and does not for the foreseeable future intend to pay, a dividend.

Other Arrangements

Other Arrangements	12 Months Ended
	Dec. 31, 2017
Other Income and Expenses [Abstract]
Other Arrangements	Other Arrangements Sale of HIV Protease Inhibitor Royalty Stream In 2008, the Company sold to a third party its rights to receive royalty payments from GlaxoSmithKline plc, net of royalty amounts to be earned by and due to a third party, for a one-time cash payment of $160.0 million . These royalty payments relate to net sales of HIV protease inhibitors, which had been developed pursuant to a collaboration agreement between the Company and GlaxoSmithKline plc. The Company has been recognizing the payment received over the expected life of the collaboration agreement with GlaxoSmithKline plc based on the units-of-revenue method. As of December 31, 2017 , the Company had $6.9 million in deferred revenues related to the one-time cash payment. In the first quarter of 2018, the Company will record a cumulative effect adjustment to its accumulated deficit equal to the amount the Company deferred as of December 31, 2017 , net of deferred costs, as there are no material performance obligations remaining related to the Company’s sales of HIV protease inhibitors. This adjustment will be pursuant to the new guidance applicable to revenue recognition that became effective January 1, 2018 that is described in Note A, “Nature of Business and Accounting Policies.”

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The components of loss before provision for (benefit from) income taxes during the three years ended December 31, 2017 consisted of the following: 2017 2016 2015 (in thousands) United States $ 330,340 $ (147,860 ) $ (272,326 ) Foreign (346,029 ) 80,494 (285,474 ) Loss before (benefit from) provision for income taxes $ (15,689 ) $ (67,366 ) $ (557,800 ) The components of the provision for (benefit from) income taxes during the three years ended December 31, 2017 consisted of the following: 2017 2016 2015 (in thousands) Current taxes: United States $ 11,559 $ (3,821 ) $ 25,623 Foreign 3,576 1,794 831 State 5,025 1,836 3,629 Total current taxes $ 20,160 $ (191 ) $ 30,083 Deferred taxes: United States $ (113,805 ) $ 18,659 $ 497 Foreign (3,222 ) (3,359 ) (355 ) State (10,457 ) 1,556 156 Total deferred taxes $ (127,484 ) $ 16,856 $ 298 (Benefit from) provision for income taxes $ (107,324 ) $ 16,665 $ 30,381 A reconciliation of the provision for (benefit from) income taxes as computed by applying the U.S. federal statutory rate of 35% to the provision for (benefit from) income taxes during the three years ended December 31, 2017 is as follows: 2017 2016 2015 (in thousands) Loss before (benefit from) provision for income taxes $ (15,689 ) $ (67,366 ) $ (557,800 ) Expected benefit from income taxes (5,491 ) (23,578 ) (195,230 ) State taxes, net of federal benefit 4,742 3,621 3,800 Foreign income tax rate differential 77,801 21,346 47,402 Tax credits (49,088 ) (47,773 ) (55,696 ) Provision for (benefit from) income taxes attributable to valuation allowances (584,917 ) 14,837 226,169 Permanent items 21,825 24,749 5,817 Rate change 575,192 12,836 (1,224 ) Stock compensation (benefit) shortfalls and cancellations (21,453 ) 4,162 951 Tax attribute expiration — 9,947 — Deconsolidation of VIE (126,183 ) — — Other 248 (3,482 ) (1,608 ) (Benefit from) provision for income taxes $ (107,324 ) $ 16,665 $ 30,381 The Company operates in many foreign tax jurisdictions, which impose income taxes at different rates than the U.S. The impact of these rate differences, which is primarily related to the Company’s operations in the U.K., is included in the “ Foreign income tax rate differential ” in the Company’s tax rate reconciliation above, which reconciles the U.S. federal statutory tax rate to the Company’s effective tax rate. In 2017, the effect of “ Permanent items ” was related to equity compensation, Research and Development Credits, Orphan Drug Credits, and foreign amortization. The change in the “ Provision for (benefit from) income taxes attributable to valuation allowances ” on deferred tax assets in the tax rate reconciliation table above is primarily related to the U.S., U.K. and Canada. In 2017 , the valuation allowance decreased by $178.2 million primarily due to the utilization of net operating losses (“NOLs”) in the U.S. and a decrease in the U.S. corporate tax rate from 35% to 21% partially offset by the adoption of ASU 2016-09. In 2016 , the valuation allowance increased by $14.8 million primarily due to an increase in tax credits in the U.S. and an increase in the net operating loss in the U.K., both due to the uncertainty in the Company’s ability to use them in future periods. In 2015 , the valuation allowance increased by $306.4 million primarily related to an increase in net operating losses that were incurred with no corresponding benefit due to the uncertainty in the Company’s ability to use them in future periods. On December 22, 2017, H.R.1., known as the Tax Cuts and Jobs Act, was signed into law. The new law did not have a significant impact on the Company’s consolidated financial statements for the year ended December 31, 2017 because it maintains a valuation allowance on the majority of its net operating losses and other deferred tax assets. However, the reduction of the U.S. federal corporate tax rate from 35% to 21% resulted in increases to the amounts reflected in “ Provision for (benefit from) income taxes attributable to valuation allowances ” and “ Rate change ” in the Company’s tax reconciliation table above for the year ended December 31, 2017 compared to the years ended December 31, 2016 and 2015. The change in the U.S. federal corporate tax rate, which is effective January 1, 2018, is also reflected in the Company’s deferred tax table below. Lastly, the Company has discussed Staff Accounting Bulletin No. 118’s (“SAB 118”) possible impact on the Company’s consolidated financial statements below. Deferred tax assets and liabilities are determined based on the difference between financial statement and tax bases using enacted tax rates in effect for the year in which the differences are expected to reverse. The components of the deferred taxes were as follows: As of December 31, 2017 2016 (in thousands) Deferred tax assets: Net operating loss $ 1,004,404 $ 1,232,399 Tax credit carryforwards 440,429 367,402 Intangible assets 54,091 34,938 Deferred revenues 19,593 31,205 Stock-based compensation 83,196 110,446 Inventories 4,250 4,705 Accrued expenses 17,808 23,078 Construction financing lease obligation 109,354 177,735 Other 1,417 27 Gross deferred tax assets 1,734,542 1,981,935 Valuation allowance (1,552,942 ) (1,731,186 ) Total deferred tax assets 181,600 250,749 Deferred tax liabilities: Property and equipment (101,019 ) (169,089 ) Acquired intangibles (6,341 ) (134,063 ) Deferred revenue (73,357 ) (73,357 ) Unrealized gain (6,401 ) (7,967 ) Net deferred tax liabilities $ (5,518 ) $ (133,727 ) The Company presents its deferred tax assets and deferred tax liabilities gross on its consolidated balance sheets. As of December 31, 2017 , $4.8 million of the deferred tax liabilities were attributable to the Company’s collaboration with BioAxone. As of December 31, 2016 , $131.4 million of the deferred tax liabilities were attributable to the Company’s collaborations with BioAxone and Parion. Please refer to Note B, “ Collaborative Arrangements and Acquisitions, ” and Note J, “Intangible Assets and Goodwill,” for further information regarding the decrease in the deferred tax liability in 2017, which was primarily related to the Company’s collaboration with Parion. For U.S. federal income tax purposes, as of December 31, 2017 , the Company had net operating loss carryforwards of approximately $3.6 billion and tax credits of $312.5 million , which may be used to offset future federal income and tax liability, respectively. For U.S. state income tax purposes, as of December 31, 2017 , the Company had net operating loss carryforwards of approximately $880.7 million and tax credits of $115.7 million , which may be used to offset future state income and tax liability, respectively. These U.S. federal and state net operating loss carryforwards and tax credits expire at various dates through 2037. The Company maintains a valuation allowance on the majority of its net operating losses and other deferred tax assets. Accordingly, the Company has not reported any benefits from income taxes relating to the remaining NOLs and income tax credit carryforwards that will be utilized in future periods in these jurisdictions. On a periodic basis, the Company reassesses the valuation allowance on its deferred income tax assets weighing positive and negative evidence to assess the recoverability of the deferred tax assets. In 2017, the Company reassessed the valuation allowance and considered negative evidence, including its cumulative losses over the three years ended December 31, 2017, and positive evidence, including its income during the year ended December 31, 2017. After assessing both the negative evidence and the positive evidence, the Company concluded that it should continue to maintain the valuation allowance on its net operating losses and the majority of its other deferred tax assets as of December 31, 2017. Based on the Company’s recent financial performance and its future projections, it could record a reversal of all, or a portion of the valuation allowance associated with U.S. deferred tax assets in future periods. However, any such change is subject to actual performance and other considerations that may present positive or negative evidence at the time of the assessment. The Company’s total deferred tax asset balance subject to the valuation allowance was approximately $1.6 billion at December 31, 2017 . Unrecognized tax benefits during the three years ended December 31, 2017 were not material to the Company’s consolidated financial statements. The Company has reviewed the tax positions taken, or to be taken, in its tax returns for all tax years currently open to examination by a taxing authority. The total amount of unrecognized tax benefits, that is the aggregate tax effect of differences between tax return positions and the benefits recognized in the financial statements, as of December 31, 2017 , 2016 and 2015 were $3.8 million , zero and $0.4 million , respectively. The Company recognizes interest and penalties related to income taxes as a component of provision for (benefit from) income taxes. As of December 31, 2017 , no interest and penalties have been accrued. The Company files U.S. federal income tax returns and income tax returns in various state, local and foreign jurisdictions. The Company is no longer subject to any tax assessment from an income tax examination in the U.S. or any other major taxing jurisdiction for years before 2011, except where the Company has net operating losses or tax credit carryforwards that originate before 2011. The Company currently is under examination in Canada for 2011 through 2013, Germany for 2012 through 2015 and Italy for 2015 and 2016. No adjustments have been reported. The Company is not under examination by any other jurisdictions for any tax year. The Company concluded audits with Internal Revenue Service, Delaware, Pennsylvania, Texas and Revenue Quebec during 2016, and Massachusetts and New York during 2015, with no material adjustments. On December 22, 2017, the SEC staff issued SAB 118 to address the application of GAAP in situations when a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of H.R.1. The Company has recognized the provisional tax impacts related to deemed repatriated earnings and the revaluation of deferred tax assets and liabilities and included these amounts in its consolidated financial statements for the year ended December 31, 2017. The Company has an accumulated deficit from its foreign operations and does not have an associated liability from the repatriation tax on accumulated earnings in H.R.1. The ultimate impact may differ from these provisional amounts, possibly materially, due to, among other things, additional analysis, changes in interpretations and assumptions the Company has made, additional regulatory guidance that may be issued, and actions the Company may take as a result of H.R.1. The Company’s accounting treatment is expected to be complete when the 2017 U.S. corporate income tax return is filed in 2018. As of December 31, 2017, foreign earnings, which were not significant, have been retained indefinitely by the Company’s foreign subsidiaries for reinvestment. Upon repatriation of those earnings, in the form of dividends or otherwise, the Company could be subject to withholding taxes payable to the various foreign countries.

Restructuring Expenses

Restructuring Expenses	12 Months Ended
	Dec. 31, 2017
Restructuring and Related Activities [Abstract]
Restructuring Expenses	Restructuring Expenses The Company has adopted several plans to restructure its facilities and operations for which it has incurred restructuring expenses in the three years ended December 31, 2017 . The most significant restructuring event during the three years ended December 31, 2017 commenced in February 2017 upon the Company’s decision to consolidate its research activities into its Boston, Milton Park and San Diego locations. The Company closed its research site in Canada as a result of this decision affecting approximately 70 positions. As of December 31, 2017 , the restructuring liability associated with this restructuring event relates to the lease for the research site in Canada that terminates in October 2018. The Company does not anticipate any significant additional charges related to this restructuring event in the future. The restructuring charge and other activities related to this restructuring event recorded during the year ended December 31, 2017 were as follows: 2017 (in thousands) Liability, beginning of the period $ — Restructuring expense 12,503 Cash payments (8,602 ) Asset impairments and other non-cash items (1,812 ) Liability, end of the period $ 2,089

Employee Benefits

Employee Benefits	12 Months Ended
	Dec. 31, 2017
Retirement Benefits [Abstract]
Employee Benefits	Employee Benefits The Company has a 401(k) retirement plan (the “Vertex 401(k) Plan”) in which substantially all of its permanent U.S. employees are eligible to participate. Participants may contribute up to 60% of their annual compensation to the Vertex 401(k) Plan, subject to statutory limitations. The Company may declare discretionary matching contributions to the Vertex 401(k) Plan. Beginning in mid-2013, the Company began paying matching contributions in the form of cash. For the years ended December 31, 2017 , 2016 and 2015 , the Company contributed approximately $12.3 million , $11.8 million and $12.8 million to the plan, respectively. As of December 31, 2017 , 754,744 shares of common stock remained available for grant under the Vertex 401(k) Plan.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Lease Obligations The Company moved into its corporate headquarters to Boston, Massachusetts in January 2014. In December 2015, the Company entered into a lease agreement for 3215 Merryfield Row, San Diego, California. Please refer to Note L, “Long Term Obligations,” for additional information regarding both of these commitments. As of December 31, 2017 , future minimum commitments under the facility leases with initial terms of more than one year were as follows: Year Fan Pier San Diego Leases Other Total Lease (in thousands) 2018 $ 61,606 $ 2,979 $ 19,866 $ 84,451 2019 72,589 5,324 15,002 92,915 2020 72,589 9,127 13,956 95,672 2021 72,589 9,127 12,163 93,879 2022 72,589 9,127 11,542 93,258 Thereafter 462,442 129,394 57,949 649,785 Total minimum lease payments $ 814,404 $ 165,078 $ 130,478 $ 1,109,960 As of December 31, 2017 , the Company’s total sublease income to be received related to its facility leases was $6.0 million , all of which relates to subleases expiring in 2018. During 2017 , 2016 and 2015 , rental expense was $19.2 million , $19.1 million and $18.1 million , respectively. The majority of the Company’s lease payments related to the Fan Pier Leases are recorded as interest expense because the Company is deemed for accounting purposes to be the owner of the Buildings. Please refer to Note L, “Long Term Obligations,” for further information. The Company has outstanding leases, which are accounted for as capital leases, for equipment and leasehold improvements. The capital leases bear interest at rates ranging from less than 1% to 9% per year. The following table sets forth the Company’s future minimum payments due under capital leases as of December 31, 2017 : Year (in thousands) 2018 $ 24,004 2019 10,252 2020 5,434 2021 3,676 2022 1,706 Thereafter 387 Total payments 45,459 Less: amount representing interest (2,432 ) Present value of payments $ 43,027 In addition, the Company has committed to make potential future milestone and royalty payments pursuant to certain collaboration agreements. Payments generally become due and payable upon the achievement of certain developmental, regulatory and/or commercial milestones. Please refer to Note B, “ Collaborative Arrangements and Acquisitions, ” for further information. Guaranties and Indemnifications As permitted under Massachusetts law, the Company’s Articles of Organization and By-laws provide that the Company will indemnify certain of its officers and directors for certain claims asserted against them in connection with their service as an officer or director. The maximum potential amount of future payments that the Company could be required to make under these indemnification provisions is unlimited. However, the Company has purchased directors’ and officers’ liability insurance policies that could reduce its monetary exposure and enable it to recover a portion of any future amounts paid. No indemnification claims currently are outstanding, and the Company believes the estimated fair value of these indemnification arrangements is minimal. The Company customarily agrees in the ordinary course of its business to indemnification provisions in agreements with clinical trial investigators and sites in its drug development programs, sponsored research agreements with academic and not-for-profit institutions, various comparable agreements involving parties performing services for the Company, and its real estate leases. The Company also customarily agrees to certain indemnification provisions in its drug discovery, development and commercialization collaboration agreements. With respect to the Company’s clinical trials and sponsored research agreements, these indemnification provisions typically apply to any claim asserted against the investigator or the investigator’s institution relating to personal injury or property damage, violations of law or certain breaches of the Company’s contractual obligations arising out of the research or clinical testing of the Company’s compounds or drug candidates. With respect to lease agreements, the indemnification provisions typically apply to claims asserted against the landlord relating to personal injury or property damage caused by the Company, to violations of law by the Company or to certain breaches of the Company’s contractual obligations. The indemnification provisions appearing in the Company’s collaboration agreements are similar to those for the other agreements discussed above, but in addition provide some limited indemnification for its collaborator in the event of third-party claims alleging infringement of intellectual property rights. In each of the cases above, the indemnification obligation generally survives the termination of the agreement for some extended period, although the Company believes the obligation typically has the most relevance during the contract term and for a short period of time thereafter. The maximum potential amount of future payments that the Company could be required to make under these provisions is generally unlimited. The Company has purchased insurance policies covering personal injury, property damage and general liability that reduce its exposure for indemnification and would enable it in many cases to recover all or a portion of any future amounts paid. The Company has never paid any material amounts to defend lawsuits or settle claims related to these indemnification provisions. Accordingly, the Company believes the estimated fair value of these indemnification arrangements is minimal. Other Contingencies The Company has certain contingent liabilities that arise in the ordinary course of its business activities. The Company accrues a reserve for contingent liabilities when it is probable that future expenditures will be made and such expenditures can be reasonably estimated. There were no material contingent liabilities accrued as of December 31, 2017 or 2016 .

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Segment Information	Segment Information Segment reporting is prepared on the same basis that the Company’s chief executive officer, who is the Company’s chief operating decision maker, manages the business, makes operating decisions and assesses performance. The Company operates in one segment, pharmaceuticals. Enterprise-wide disclosures about revenues, significant customers, and property and equipment, net by location are presented below. Revenues by Product Product revenues, net consisted of the following: 2017 2016 2015 (in thousands) ORKAMBI $ 1,320,850 $ 979,590 $ 350,663 KALYDECO 844,630 703,432 631,674 INCIVEK — 610 17,987 Total product revenues, net $ 2,165,480 $ 1,683,632 $ 1,000,324 Revenues by Geographic Location Net product revenues are attributed to countries based on the location of the customer. Collaborative and royalty revenues are attributed to countries based on the location of the Company’s subsidiary associated with the collaborative arrangement related to such revenues. Total revenues from external customers and collaborators by geographic region consisted of the following: 2017 2016 2015 (in thousands) United States $ 1,986,786 $ 1,321,807 $ 763,316 Outside of the United States Europe 420,317 320,456 219,596 Other 81,549 59,914 49,424 Total revenues outside of the United States 501,866 380,370 269,020 Total revenues $ 2,488,652 $ 1,702,177 $ 1,032,336 In 2017 , 2016 and 2015 , revenues attributable to the U.K. were the largest contributor to the Company’s European revenues. Significant Customers Gross revenues and accounts receivable from each of the Company’s customers who individually accounted for 10% or more of total gross revenues and/or 10% or more of total gross accounts receivable consisted of the following: Percent of Total Gross Revenues Percent of Gross Accounts Receivable Year Ended December 31, As of December 31, 2017 2016 2015 2017 2016 Walgreen Co. 17 % 19 % 20 % 20 % 15 % Accredo/Curascript 14 % 15 % 15 % 12 % 10 % CVS/Caremark <10 % 19 % 17 % n/a 17 % Property and Equipment, Net by Location Property and equipment, net by location consisted of the following: As of December 31, 2017 2016 (in thousands) United States $ 753,128 $ 665,552 Outside of the United States United Kingdom 31,279 26,921 Other 5,030 5,889 Total property and equipment, net outside of the United States 36,309 32,810 Total property and equipment, net $ 789,437 $ 698,362

Quarterly Financial Data (unaud

Quarterly Financial Data (unaudited)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data (unaudited)	Quarterly Financial Data (unaudited) The following table sets forth the Company’s quarterly financial data for the two years ended December 31, 2017 . Three Months Ended March 31, June 30, September 30, December 31, (in thousands, except per share amounts) Revenues: Product revenues, net $ 480,622 $ 513,988 $ 549,642 $ 621,228 Royalty revenues 1,551 2,861 2,231 1,345 Collaborative revenues (1) 232,545 27,286 26,292 29,061 Total revenues 714,718 544,135 578,165 651,634 Costs and expenses: Cost of product revenues 46,242 70,535 72,186 83,712 Royalty expenses 746 670 688 340 Research and development expenses (2) 273,563 289,451 454,947 306,664 Sales, general and administrative expenses 113,326 127,249 120,710 134,794 Restructuring expenses 9,999 3,523 337 387 Intangible asset impairment charge (3) — — 255,340 — Total costs and expenses 443,876 491,428 904,208 525,897 Income (loss) from operations 270,842 52,707 (326,043 ) 125,737 Interest expense, net (16,765 ) (14,664 ) (13,574 ) (12,547 ) Other expense, net (3) (544 ) (2,537 ) (77,553 ) (748 ) Income (loss) before provision for (benefit from) income taxes 253,533 35,506 (417,170 ) 112,442 Provision for (benefit from) income taxes (3) 3,985 4,337 (125,903 ) 10,257 Net income (loss) 249,548 31,169 (291,267 ) 102,185 (Income) loss attributable to noncontrolling interest (3) (1,792 ) (13,173 ) 188,315 (1,501 ) Net income (loss) attributable to Vertex $ 247,756 $ 17,996 $ (102,952 ) $ 100,684 Amounts per share attributable to Vertex common shareholders: Net income (loss): Basic $ 1.01 $ 0.07 $ (0.41 ) $ 0.40 Diluted $ 0.99 $ 0.07 $ (0.41 ) $ 0.39 Shares used in per share calculations: Basic 246,024 247,521 250,268 251,557 Diluted 248,700 251,635 250,268 256,804 Three Months Ended March 31, June 30, September 30, December 31, (in thousands, except per share amounts) Revenues: Product revenues, net $ 394,410 $ 425,651 $ 409,689 $ 453,882 Royalty revenues 3,596 5,282 3,835 3,887 Collaborative revenues 74 675 259 937 Total revenues 398,080 431,608 413,783 458,706 Costs and expenses: Cost of product revenues 49,789 44,154 53,222 59,646 Royalty expenses 860 1,098 855 836 Research and development expenses (4) 255,860 271,008 272,370 248,452 Sales, general and administrative expenses 105,214 111,652 106,055 109,908 Restructuring expenses 687 343 8 224 Total costs and expenses 412,410 428,255 432,510 419,066 (Loss) income from operations (14,330 ) 3,353 (18,727 ) 39,640 Interest expense, net (20,698 ) (20,155 ) (20,140 ) (20,439 ) Other income (expense), net 4,411 (1,219 ) (167 ) 1,105 (Loss) income before provision for (benefit from) income taxes (30,617 ) (18,021 ) (39,034 ) 20,306 Provision for (benefit from) income taxes 5,485 18,130 503 (7,453 ) Net (loss) income (36,102 ) (36,151 ) (39,537 ) 27,759 (Income) loss attributable to noncontrolling interest (5,529 ) (28,374 ) 696 5,186 Net (loss) income attributable to Vertex $ (41,631 ) $ (64,525 ) $ (38,841 ) $ 32,945 Amounts per share attributable to Vertex common shareholders: Net (loss) income: Basic $ (0.17 ) $ (0.26 ) $ (0.16 ) $ 0.13 Diluted $ (0.17 ) $ (0.26 ) $ (0.16 ) $ 0.13 Shares used in per share calculations: Basic 243,831 244,482 244,920 245,454 Diluted 243,831 244,482 244,920 247,757 1. In the first quarter of 2017, the Company recognized $230.0 million of collaborative revenues related to an upfront payment from Merck KGaA pursuant to the Company’s collaboration with Merck KGaA. In each of the second and third quarters of 2017, the Company recognized $20.0 million of collaborative revenues related to payments that Parion, which was a variable interest entity during these periods, received from Shire pursuant to a license agreement. In the fourth quarter of 2017, the Company recognized $25.0 million of collaborative revenues related to a milestone achieved pursuant to its license agreement with Janssen Inc. pursuant to which Janssen is developing JNJ-63623872 for the treatment of influenza. See Note B, “ Collaborative Arrangements and Acquisitions, ” for further information. 2. In the third quarter of 2017, the Company incurred research and development expenses of approximately $160.0 million to acquire certain CF assets including VX-561 from Concert. See Note B, “ Collaborative Arrangements and Acquisitions, ” for further information. 3. In the third quarter of 2017, the Company recorded a $255.3 million intangible asset impairment charge related to Parion’s pulmonary ENaC platform indefinite-lived in-process research and development asset, a decrease in the fair value of the contingent payments payable by the Company to Parion of $69.6 million and benefit from income taxes of $126.2 million resulting from these charges. These charges and benefit from income taxes were attributable to noncontrolling interest. See Note B, “ Collaborative Arrangements and Acquisitions, ” and Note J, “Intangible Assets and Goodwill,” for further information. 4. In the second quarter of 2016, the Company incurred research and development expenses of approximately $10.0 million to acquire certain early-stage research assets. In the third quarter of 2016, the Company incurred research and development expenses related to a $20.0 million upfront payment to Moderna Therapeutics, Inc. See Note B, “ Collaborative Arrangements and Acquisitions, ” for further information.

Nature of Business and Accoun30

Nature of Business and Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The consolidated financial statements reflect the operations of (i) the Company, (ii) its wholly-owned subsidiaries and (iii) consolidated variable interest entities (“VIEs”). On September 30, 2017, the Company deconsolidated Parion Sciences, Inc. (“Parion”), a VIE the Company had consolidated since June 4, 2015. The Company's consolidated balance sheet as of December 31, 2017 excludes Parion. All material intercompany balances and transactions have been eliminated. The Company operates in one segment, pharmaceuticals. Please refer to Note T, “Segment Information,” for enterprise-wide disclosures regarding the Company’s revenues, major customers and long-lived assets by geographic area. The Company has reclassified certain amounts in the consolidated balance sheets for the period ended December 31, 2016 between “Accounts receivable, net” and “Prepaid expenses and other current assets” to conform with the current year presentation.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in accordance with accounting principles generally accepted in the United States of America (“GAAP”) requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the amounts of revenues and expenses during the reported periods. Significant estimates in these consolidated financial statements have been made in connection with the calculation of revenues, inventories, research and development expenses, stock-based compensation expense, the fair value of intangible assets, goodwill, noncontrolling interest, the consolidation and deconsolidation of VIEs, leases, the fair value of cash flow hedges, deferred tax asset valuation allowances and the provision for or benefit from income taxes. The Company bases its estimates on historical experience and various other assumptions, including in certain circumstances future projections, that management believes to be reasonable under the circumstances. Actual results could differ from those estimates. Changes in estimates are reflected in reported results in the period in which they become known.
Revenue Recognition	Revenue Recognition Product Revenues, Net The Company sells its products principally to a limited number of specialty pharmacy providers in North America as well as government-owned and supported customers in international markets (collectively, its “Customers”). The Company’s Customers in North America subsequently resell the products to patients and health care providers. The Company recognizes net revenues from product sales upon delivery as long as (i) there is persuasive evidence that an arrangement exists between the Company and the Customer, (ii) collectibility is reasonably assured and (iii) the price is fixed or determinable. In order to conclude that the price is fixed or determinable, the Company must be able to (i) calculate its gross product revenues from sales to Customers and (ii) reasonably estimate its net product revenues upon delivery to its Customer’s locations. The Company calculates gross product revenues based on the price that the Company charges its Customers. The Company estimates its net product revenues by deducting from its gross product revenues (a) trade allowances, such as invoice discounts for prompt payment and Customer fees, (b) estimated government and private payor rebates, chargebacks and discounts, (c) estimated reserves for expected product returns and (d) estimated costs of co-pay assistance programs for patients, as well as other incentives for certain indirect customers. Trade Allowances: The Company generally provides invoice discounts on product sales to its Customers for prompt payment and pays fees for distribution services, such as fees for certain data that Customers provide to the Company. The payment terms for sales to Customers in the United States (“U.S.”) generally include a discount for payment within 30 days. The Company expects that, based on its experience, its Customers will earn these discounts and fees, and deducts the full amount of these discounts and fees from its gross product revenues and accounts receivable at the time such revenues are recognized. Rebates, Chargebacks and Discounts: The Company contracts primarily with government agencies (its “Third-party Payors”) so that products will be eligible for purchase by, or partial or full reimbursement from, such Third-party Payors. The Company estimates the rebates, chargebacks and discounts it will provide to Third-party Payors and deducts these estimated amounts from its gross product revenues at the time the revenues are recognized. For each product, the Company estimates the aggregate rebates, chargebacks and discounts that it will provide to Third-party Payors based upon (i) the Company’s contracts with these Third-party Payors, (ii) the government-mandated discounts applicable to government-funded programs, (iii) information obtained from the Company’s Customers and other third-party data regarding the payor mix for such product and (iv) historical experience. Product Returns: The Company estimates the amount of each product that will be returned and deducts these estimated amounts from its gross revenues at the time the revenues are recognized. The Company’s Customers have the right to return unopened unprescribed packages, subject to contractual limitations. To date, product returns have been minimal and, based on inventory levels held by its Customers and its distribution model, the Company believes that returns of its products will continue to be minimal. Other Incentives: Other incentives that the Company offers include co-pay mitigation rebates provided by the Company to commercially insured patients who have coverage and who reside in states that permit co-pay mitigation programs. The Company’s co-pay mitigation programs are intended to reduce each participating patient’s portion of the financial responsibility for a product’s purchase price to a specified dollar amount. Based upon the terms of the Company’s co-pay mitigation programs, the Company estimates average co-pay mitigation amounts for each of its products in order to establish its accruals for co-pay mitigation rebates and deducts these estimated amounts from its gross product revenues at the later of the date (i) the revenues are recognized or (ii) the incentive is offered. The Company’s co-pay mitigation rebates are subject to expiration. The Company makes significant estimates and judgments that materially affect the Company’s recognition of net product revenues. The Company adjusts its estimated rebates, chargebacks and discounts based on new information, including information regarding actual rebates, chargebacks and discounts for its products, as it becomes available. Claims by third-party payors for rebates, chargebacks and discounts frequently are submitted to the Company significantly after the related sales, potentially resulting in adjustments in the period in which the new information becomes known. In 2017, the Company’s adjustments relating to prior period sales were less than 0.5% of total net product revenues and primarily related to U.S. rebates, chargebacks and discounts. In 2016, the Company’s adjustments relating to prior period sales were insignificant. In 2015, the Company’s adjustments relating to prior period sales principally related to the Company’s estimates for INCIVEK following the Company’s withdrawal of INCIVEK from the market in the U.S. in the fourth quarter of 2014. In certain instances, the Company may be unable to reasonably conclude that the price is fixed or determinable at the time of delivery, in which case it defers the recognition of revenues. Once the Company is able to determine that the price is fixed or determinable, it recognizes the net product revenues associated with the units in which revenue recognition was deferred. French Early Access Programs The Company began distributing ORKAMBI through early access programs in France during the fourth quarter of 2015. The Company’s ORKAMBI net product revenues for the three years ended December 31, 2017 do not include any net product revenues from sales of ORKAMBI in France because the price was not fixed or determinable. As of December 31, 2017 , the Company’s consolidated balance sheet includes $232.4 million collected in France related to shipments of ORKAMBI under the early access programs that is classified as “Customer deposits.” The Company expects that the difference between the amounts collected based on the invoiced price and the final price for ORKAMBI in France will be returned to the French government. Because the Company concluded that the price was not fixed or determinable as of December 31, 2017, the amounts classified as “Customer deposits” related to shipments of ORKAMBI under early access programs will be subject to the new guidance applicable to revenue recognition that became effective January 1, 2018. Pursuant to the new guidance, the Company will record a cumulative effect adjustment to the Company’s accumulated deficit in the first quarter of 2018. The amount of the adjustment to accumulated deficit will be determined based upon (i) the status of pricing discussions in France upon adoption and (ii) the Company’s estimate of the amount of consideration the Company expects to retain related to ORKAMBI sales in France that occurred on or prior to December 31, 2017 that will not be subject to a significant reversal in amounts recognized. For ORKAMBI sales in France that occur after December 31, 2017 under the early access programs, the Company will recognize net product revenues based on the Company’s estimate of consideration the Company expects to retain that will not be subject to a significant reversal in amounts recognized. In periods after the first quarter of 2018, if the Company’s estimate regarding the amounts it will receive for ORKAMBI supplied pursuant to these programs changes, the effect of the change in estimate would be reflected in net product revenues in the period in which the change in estimate occurred. Please refer to Recent Accounting Pronouncements included in this Note A “Nature of Business and Accounting Policies” below for more information regarding the new revenue recognition guidance. Royalty Revenues The Company has sold its rights to receive certain royalties on sales of an HIV protease inhibitor (fosamprenavir) and recognizes the revenues related to this sale as royalty revenues. Pursuant to the revenue recognition guidance that was in effect until December 31, 2017, in the circumstance where the Company sold its rights to future royalties under a license agreement and also maintained continuing involvement in the royalty arrangement (but not significant continuing involvement in the generation of the cash flows payable to the purchaser of the future royalty rights), the Company deferred recognition of the proceeds it received for the royalty stream. It recognized these deferred revenues over the life of the license agreement utilizing the units-of-revenue method pursuant to this revenue recognition guidance. In the first quarter of 2018, the Company will record a $6.5 million cumulative effect adjustment to its accumulated deficit equal to the net deferred revenues and costs recorded as of December 31, 2017. This adjustment will be recorded utilizing the modified retrospective approach upon adoption of the new revenue recognition guidance described in Recent Accounting Pronouncements included in this Note A “Nature of Business and Accounting Policies” below that became effective January 1, 2018. The adjustment will be made because there are no material performance obligations remaining related to the royalty arrangement. The Company does not expect to record any royalty revenues in future periods based on sales of the HIV protease inhibitor. Please refer to Note O, “Other Arrangements” for further information related to this transaction. Collaborative Revenues The Company recognizes collaborative revenues generated through collaborative research, development and/or commercialization agreements. The terms of these agreements typically include payment to the Company of one or more of the following: nonrefundable, up-front license fees; development and commercial milestone payments; funding of research and/or development activities; and royalties on net sales of licensed products. Each of these types of payments results in collaborative revenues except for revenues from royalties on net sales of licensed products, which are classified as royalty revenues. For each collaborative research, development and/or commercialization agreement that result in revenues, the Company determines (i) whether multiple deliverables exist, (ii) whether the undelivered elements have value to the customer on a stand-alone basis, (iii) how the deliverables should be separated and (iv) how the consideration should be allocated to the deliverables. For arrangements entered into or materially modified after January 1, 2011, the Company allocates consideration in an arrangement using the relative selling price method based on management’s best estimate of selling price of deliverables if it does not have vendor-specific objective evidence or third-party evidence. As part of the accounting for these agreements, the Company must develop assumptions that require judgment to determine the best estimate of selling price. Key assumptions utilized by the Company to determine the best estimate of selling price may include forecasted revenues, patient enrollment requirements from regulatory authorities, development timelines, reimbursement rates for personnel costs, discount rates, and estimated third-party development costs. The Company evaluates amendments to its existing arrangements to determine whether they have been materially modified. In making its determination that an arrangement has been materially modified, the Company considers whether there have been significant changes to the consideration under the arrangement, the deliverables under the arrangement, the timing of deliverables and the period of the arrangement. If the arrangement is determined to have been materially modified, the Company allocates fixed consideration under the arrangement using its best estimate of selling price to the remaining undelivered elements at the date of material modification. Any consideration remaining after the allocation is recognized as revenue. Up-front License Fees: If the license to the Company’s intellectual property is determined to have stand-alone value from the other deliverables identified in the arrangement, the Company recognizes revenues from nonrefundable, up-front license fees upon delivery. If these licenses do not have stand-alone value, the Company recognizes revenues from nonrefundable, up-front license fees on a straight-line basis over the contracted or estimated period of performance. The Company evaluates the period of performance each reporting period and adjusts the period of performance on a prospective basis if there are changes to be made. Milestone Payments: At the inception of each agreement that includes research and development milestone payments, the Company evaluates whether each milestone is substantive. The Company recognizes revenues related to substantive milestones in full in the period in which the substantive milestone is achieved if payment is reasonably assured. If a milestone is not considered substantive, the Company recognizes the applicable milestone payment over the period of performance. Research and Development Activities: If the Company is entitled to reimbursement from its collaborators for specified research and development expenses, the Company determines whether the research and development funding would result in collaborative revenues or an offset to research and development expenses in accordance with the provisions of gross or net revenue presentation.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject the Company to concentration of credit risk consist principally of money market funds and marketable securities. The Company places these investments with highly rated financial institutions, and, by policy, limits the amounts of credit exposure to any one financial institution. These amounts at times may exceed federally insured limits. The Company also maintains a foreign currency hedging program that includes foreign currency forward contracts with several counterparties. The Company has not experienced any credit losses related to these financial instruments and does not believe it is exposed to any significant credit risk related to these instruments. The Company also is subject to credit risk from its accounts receivable related to its product sales and collaborators. The Company evaluates the creditworthiness of each of its customers and has determined that all of its material customers are creditworthy.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less at the date of purchase to be cash equivalents.
Marketable Securities	Marketable Securities The Company’s marketable securities consist of investments in government-sponsored enterprise securities, corporate equity securities, corporate debt securities and commercial paper that are classified as available-for-sale as of December 31, 2017 . The Company classifies marketable securities available to fund current operations as current assets on its consolidated balance sheets. Marketable securities are classified as long-term assets on the consolidated balance sheets if (i) they have been in an unrealized loss position for longer than one year and (ii) the Company has the ability and intent to hold them (a) until the carrying value is recovered and (b) such holding period may be longer than one year. The Company’s marketable securities are stated at fair value with their unrealized gains and losses included as a component of accumulated other comprehensive income (loss), which is a separate component of shareholders’ equity, until such gains and losses are realized. The fair value of these securities is based on quoted prices for identical or similar assets. The Company reviews investments in marketable securities for other-than-temporary impairment whenever the fair value of an investment is less than the amortized cost and evidence indicates that an investment’s carrying amount is not recoverable within a reasonable period of time. To determine whether an impairment is other-than-temporary, the Company considers whether it has an intent to sell, or whether it is more likely than not that the Company will be required to sell, the investment before recovery of the investment’s amortized cost basis. Evidence considered in this assessment includes reasons for the impairment, compliance with the Company’s investment policy, the severity and the duration of the impairment and changes in value subsequent to year-end. If a decline in the fair value is considered other-than-temporary, based on available evidence, the unrealized loss is transferred from other comprehensive income (loss) to the consolidated statements of operations. Realized gains and losses are determined using the specific identification method and are included in other income (expense), net in the consolidated statements of operations
Accounts Receivable	Accounts Receivable The Company deducts trade allowances for prompt payment and fees for distribution services from its accounts receivable based on its experience that the Company’s Customers will earn these discounts and fees. The Company’s estimates for its allowance for doubtful accounts, which have not been significant to date, are determined based on existing contractual payment terms and historical payment patterns.
Stock-based Compensation Expense	Stock-based Compensation Expense The Company expenses the fair value of employee stock options and other forms of stock-based employee compensation over the associated employee service period on a straight-line basis. Stock-based compensation expense is determined based on the fair value of the award at the grant date and is adjusted each period to reflect actual forfeitures and the outcomes of certain performance conditions. For awards with performance conditions in which the award does not vest unless the performance condition is met, the Company recognizes expense if, and to the extent that, the Company estimates that achievement of the performance condition is probable. If the Company concludes that vesting is probable, it recognizes expense from the date it reaches this conclusion through the estimated vesting date. For awards with performance conditions that accelerate vesting of the award, the Company estimates the likelihood of satisfaction of the performance conditions, which affects the period over which the expense is recognized, and recognizes the expense using the accelerated attribution model. The Company provides to employees who have rendered a certain number of years’ to the Company and meet certain age requirements, partial or full acceleration of vesting of these equity awards, subject to certain conditions including a notification period, upon a termination of employment other than for cause. Less than 5% of the Company’s employees were eligible for partial or full acceleration of any of their equity awards as of December 31, 2017 . The Company recognizes stock-based compensation expense related to these awards over a service period reflecting qualified employees’ eligibility for partial or full acceleration of vesting
Research and Development Expenses	Research and Development Expenses The Company expenses as incurred all research and development expenses, including amounts funded by research and development collaborations. The Company capitalizes nonrefundable advance payments made by the Company for research and development activities and expenses the payments as the related goods are delivered or the related services are performed. Research and development expenses are comprised of costs incurred by the Company in performing research and development activities, including salary and benefits; stock-based compensation expense; laboratory supplies and other direct expenses; outsourced services, including clinical trial and pharmaceutical development costs; collaboration and asset acquisition payments; expenses associated with drug supplies that are not being capitalized; and infrastructure costs, including facilities costs and depreciation expense
Advertising Expenses	Advertising Expenses The Company expenses the costs of advertising, including promotional expenses, as incurred
Inventories	Inventories The Company values its inventories at the lower-of-cost or net realizable value. The Company determines the cost of its inventories, which includes amounts related to materials and manufacturing overhead, on a first-in, first-out basis. The Company performs an assessment of the recoverability of capitalized inventory during each reporting period, and writes down any excess and obsolete inventories to their net realizable value in the period in which the impairment is first identified. Shipping and handling costs incurred for inventory purchases are capitalized and recorded upon sale in cost of product revenues in the consolidated statements of operations. Shipping and handling costs incurred for product shipments are recorded as incurred in cost of product revenues in the consolidated statements of operations. The Company capitalizes inventories produced in preparation for initiating sales of a drug candidate when the related drug candidate is considered to have a high likelihood of regulatory approval and the related costs are expected to be recoverable through sales of the inventories. In determining whether or not to capitalize such inventories, the Company evaluates, among other factors, information regarding the drug candidate’s safety and efficacy, the status of regulatory submissions and communications with regulatory authorities and the outlook for commercial sales, including the existence of current or anticipated competitive drugs and the availability of reimbursement. In addition, the Company evaluates risks associated with manufacturing the drug candidate and the remaining shelf-life of the inventories
Property and Equipment	Property and Equipment Property and equipment are recorded at cost. Depreciation expense is recorded using the straight-line method over the estimated useful life of the related asset, generally seven to ten years for furniture and equipment, three to five years for computers and software, 40 years for buildings and for leasehold improvements, the shorter of the useful life of the improvements or the estimated remaining life of the associated lease. Amortization expense of assets acquired under capital leases is included in depreciation expense. Maintenance and repairs to an asset that do not improve or extend its life are charged to operations. When assets are retired or otherwise disposed of, the assets and related accumulated depreciation are eliminated from the accounts and any resulting gain or loss is reflected in the Company’s consolidated statements of operations. The Company performs an assessment of the fair value of the assets if indicators of impairment are identified during a reporting period and records the assets at the lower of the net book value or the fair value of the assets. The Company capitalizes internal costs incurred to develop software for internal use during the application development stage. The Company expenses costs related to the planning and post-implementation phases of development of software for internal use as these costs are incurred. Maintenance and enhancement costs (including costs in the post-implementation stages) are expensed as incurred, unless such costs relate to substantial upgrades and enhancements to the software resulting in added functionality, in which case the costs are capitalized. Amortization of capitalized internally developed software costs is recorded in depreciation expense over the useful life of the related asset. The Company records certain construction costs incurred by a landlord as an asset and a corresponding financing obligation on the Company’s consolidated balance sheets when the Company is determined to be the owner of a building during construction for accounting purposes. Upon completion of the project, the Company performs a sale-leaseback analysis to determine if the Company can remove the assets and corresponding liability from its consolidated balance sheet
Capital Leases	Capital Leases The assets and liabilities associated with capital lease agreements are recorded at the present value of the minimum lease payments at the inception of the lease agreement. The assets are depreciated using the straight-line method over the shorter of the useful life of the related asset or the remaining life of the associated lease. Amortization of assets that the Company leases pursuant to a capital lease is included in depreciation expense. The Company performs an assessment of the fair value of the assets if indicators of impairment are identified during a reporting period and records the assets at the lower of the net book value or the fair value of the assets. Assets recorded under capital leases are recorded within “Property and equipment, net” and liabilities related to those assets are recorded within “Capital lease obligations, current portion” and “Capital lease obligations, excluding current portion” on the Company’s consolidated balance sheets.
Income Taxes	Income Taxes Deferred tax assets and liabilities are recognized for the expected future tax consequences of temporary differences between the financial statement carrying amounts and the income tax bases of assets and liabilities. A valuation allowance is applied against any net deferred tax asset if, based on the available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. On a periodic basis, the Company reassesses the valuation allowance on its deferred income tax assets weighing positive and negative evidence to assess the recoverability of its deferred tax assets. The Company includes its recent financial performance and its future projections in this periodic assessment. The Company records liabilities related to uncertain tax positions by prescribing a minimum recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. The Company does not believe any such uncertain tax positions currently pending will have a material adverse effect on its consolidated financial statements
Variable Interest Entities	Variable Interest Entities The Company reviews each collaboration agreement pursuant to which it licenses assets owned by a collaborator in order to determine whether or not it has a variable interest via the license agreement with the collaborator and if the variable interest is a variable interest in the collaborator as a whole. In assessing whether the Company has a variable interest in the collaborator as a whole, the Company considers and makes judgments regarding the purpose and design of the entity, the value of the licensed assets to the collaborator, the value of the collaborator’s total assets and the significant activities of the collaborator. If the Company has a variable interest in the collaborator as a whole, the Company assesses whether or not the Company is the primary beneficiary of that VIE based on a number of factors, including (i) which party has the power to direct the activities that most significantly affect the VIE’s economic performance, (ii) the parties’ contractual rights and responsibilities pursuant to the collaboration agreement and (iii) which party has the obligation to absorb losses of or the right to receive benefits from the VIE that could be significant to the VIE. If the Company determines it is the primary beneficiary of a VIE at the onset of the collaboration agreement, the collaboration is treated as a business combination and the Company consolidates the financial statements of the VIE into the Company’s consolidated financial statements. The Company evaluates whether it continues to be the primary beneficiary of any consolidated VIEs on a quarterly basis. If the Company determines that it is no longer the primary beneficiary of a consolidated VIE, or no longer has a variable interest in the VIE, it deconsolidates the VIE in the period that the determination is made. Assets recorded as a result of consolidating VIEs’ financial results into the Company’s consolidated balance sheet do not represent additional assets that could be used to satisfy claims against the Company’s general assets. With respect to the Company’s VIEs, the VIEs’ assets are not significant, except for the VIEs’ cash and cash equivalents. The Company records the cash and cash equivalents of consolidated VIEs as “Restricted cash and cash equivalents (VIE)” because the Company does not have control over the VIEs’ cash and cash equivalents. The VIEs’ cash and cash equivalents were $1.5 million and $47.8 million as of December 31, 2017 and 2016 , respectively. The Company also has recorded the liabilities of its consolidated VIEs for which creditors do not have recourse to the Company’s general assets outside of the VIE
Fair Value of In-process Research and Development Assets and Contingent Payments	Fair Value of In-process Research and Development Assets and Contingent Payments The present-value models used to estimate the fair values of research and development assets and contingent payments pursuant to collaborations incorporate significant assumptions, including: assumptions regarding the probability of obtaining marketing approval and/or achieving relevant development milestones for a drug candidate; estimates regarding the timing of and the expected costs to develop a drug candidate; estimates of future cash flows from potential product sales and/or the potential to achieve certain commercial milestones with respect to a drug candidate; and the appropriate discount and tax rates.
In-process Research and Development Assets	In-process Research and Development Assets The Company records the fair value of in-process research and development assets as of the transaction date of a business combination. Each of these assets is accounted for as an indefinite-lived intangible asset and is maintained on the Company’s consolidated balance sheet until either the project underlying it is completed or the asset becomes impaired. If the asset becomes impaired or is abandoned, the carrying value of the related intangible asset is written down to its fair value, and an impairment charge is recorded in the period in which the impairment occurs. If a project is completed, the carrying value of the related intangible asset is amortized as a part of cost of product revenues over the remaining estimated life of the asset beginning in the period in which the project is completed. In-process research and development assets are tested for impairment on an annual basis as of October 1, and more frequently if indicators are present or changes in circumstances suggest that impairment may exist. In-process research and development assets that are acquired in a transaction that does not qualify as a business combination under GAAP and that do not have an alternative future use are expensed in the period in which the assets are acquired.
Goodwill	Goodwill The difference between the purchase price and the fair value of assets acquired and liabilities assumed in a business combination is allocated to goodwill. Goodwill is evaluated for impairment on an annual basis as of October 1, and more frequently if indicators are present or changes in circumstances suggest that impairment may exist
Noncontrolling Interest	Noncontrolling Interest The Company records noncontrolling interest, which has historically related to consolidated VIEs, on its consolidated balance sheets. The Company records net loss (income) attributable to noncontrolling interest on its consolidated statements of operations, reflecting the VIEs’ net loss (income) for the reporting period, adjusted for changes in the noncontrolling interest holders’ claim to net assets, including contingent milestone, royalty and option payments, each of which is evaluated each reporting period
Deconsolidation and Discounted Operations	Deconsolidation and Discontinued Operations Upon the occurrence of certain events and on a regular basis, the Company evaluates whether it no longer has a controlling interest in its subsidiaries, including consolidated VIEs. If the Company determines it no longer has a controlling interest, the subsidiary is deconsolidated. The Company records a gain or loss on deconsolidation based on the difference on the deconsolidation date between (i) the aggregate of (a) the fair value of any consideration received, (b) the fair value of any retained noncontrolling investment in the former subsidiary and (c) the carrying amount of any noncontrolling interest in the subsidiary being deconsolidated, less (ii) the carrying amount of the former subsidiary’s assets and liabilities. The Company assesses whether a deconsolidation is required to be presented as discontinued operations in its consolidated financial statements on the deconsolidation date. This assessment is based on whether or not the deconsolidation represents a strategic shift that has or will have a major effect on the Company’s operations or financial results. If the Company determines that a deconsolidation requires presentation as a discontinued operation on the deconsolidation date, or at any point during the one year period following such date, it will present the former subsidiary as a discontinued operation in current and comparative period financial statements
Derivative Instruments, Embedded Derivatives and Hedging Activities	Derivative Instruments, Embedded Derivatives and Hedging Activities The Company has entered into financial transactions involving free-standing derivative instruments and embedded derivatives in the past. Embedded derivatives are required to be bifurcated from the host instruments if the derivatives are not clearly and closely related to the host instruments. The Company determines the fair value of each derivative instrument or embedded derivative that is identified on the date of issuance and at the end of each quarterly period. The estimates of the fair value of the derivatives include significant assumptions regarding the estimates market participants would make in order to evaluate these derivatives. The Company recognizes the fair value of hedging instruments that are designated and qualify as hedging instruments pursuant to GAAP, foreign currency forward contracts, as either assets or liabilities on the consolidated balance sheets. Changes in the fair value of these instruments are recorded each period in “ Accumulated other comprehensive (loss) income ”, which is a separate component of shareholders’ equity, as unrealized gains and losses until the forecasted underlying transaction occurs. Unrealized gains and losses on these foreign currency forward contracts are included in (i) “Prepaid expenses and other current assets,” (ii) “Other assets,” (iii) “Other liabilities, current portion” and (iv) “Other liabilities, excluding current portion,” respectively, on the Company’s consolidated balance sheets. Realized gains and losses for the effective portion of such contracts are recognized in “Product revenues, net” in the consolidated statement of operations when the contract is settled with the counterparty. The Company classifies the cash flows from hedging instruments in the same category as the cash flows from the hedged items. Certain of the Company’s hedging instruments are subject to master netting arrangements to reduce the risk arising from such transactions with its counterparties. The Company presents unrealized gains and losses on its foreign currency forward contracts on a gross basis within its consolidated balance sheets. The Company assesses, both at inception and on an ongoing basis, whether the foreign currency forward contracts used in hedging transactions are highly effective in offsetting the changes in cash flows of the hedged items. The Company also assesses hedge ineffectiveness quarterly and, if determined to be ineffective, records the gain or loss related to the ineffective portion to earnings in “ Other (expense) income, net ” in its consolidated statements of operations. The Company did not record any ineffectiveness related to these hedging transactions in the three years ended December 31, 2017 . The Company also enters into foreign currency forward contracts with contractual maturities of less than one month designed to mitigate the effect of changes in foreign exchange rates on monetary assets and liabilities including intercompany balances. These contracts are not designated as hedging instruments pursuant to GAAP. Realized gains and losses for such contracts are recognized in “ Other (expense) income, net ” in the consolidated statement of operations when the contract is settled with the counterparty.
Restructuring Expenses	Restructuring Expenses The Company records costs and liabilities associated with exit and disposal activities based on estimates of fair value in the period the liabilities are incurred. The Company’s exit and disposal activities have primarily been associated with the Company’s facilities, but also have included the termination of employees in some cases. The Company’s initial estimate of its liabilities for net ongoing costs associated with its facility obligations are recorded at fair value on the cease use date. In estimating the expenses and liabilities related to these facilities, the Company utilizes the probability-weighted discounted cash-flows of the Company’s ongoing lease obligations. In estimating the expense and liability under its lease obligations, the Company estimates (i) the costs to be incurred to satisfy rental and build-out commitments under the lease (including operating costs), (ii) the lead-time necessary to sublease the space, (iii) the projected sublease rental rates and (iv) the anticipated durations of subleases. The Company uses a credit-adjusted risk-free rate to discount the estimated cash flows. In periods subsequent to the initial measurement, the Company measures changes to the liability using the credit-adjusted risk-free discount rate applied in the initial period. The Company evaluates and adjusts these liabilities as appropriate for changes in circumstances on a quarterly basis. Changes to the Company’s estimate of these liabilities are recorded as additional restructuring expenses (credits). In addition, because the Company’s estimate of these liabilities includes the application of a discount rate to reflect the time-value of money, the Company records imputed interest costs related to these liabilities each quarter. These costs are included in “Restructuring expenses” on the Company’s consolidated statements of operations.
Comprehensive Income (Loss)	Comprehensive Income (Loss) Comprehensive income (loss) consists of net income (loss) and other comprehensive income (loss), which includes foreign currency translation adjustments and unrealized gains and losses on foreign currency forward contracts and certain marketable securities. For purposes of comprehensive income (loss) disclosures, the Company records provisions for or benefits from income taxes related to the unrealized gains and losses on foreign currency forward contracts and certain marketable securities. The Company does not record provisions for or benefits from income taxes related to the cumulative translation adjustment, as the Company intends to permanently reinvest undistributed earnings in its foreign subsidiaries
Foreign Currency Translation and Transactions	Foreign Currency Translation and Transactions The Company primarily operates with entities that have the U.S. dollar denominated as their functional currency. Non-U.S. dollar denominated functional currency subsidiaries have assets and liabilities translated into U.S. dollars at rates of exchange in effect at the end of the year. Revenue and expense amounts are translated using the average exchange rates for the period. Net unrealized gains and losses resulting from foreign currency translation are included in “ Accumulated other comprehensive (loss) income ”, which is a separate component of shareholders’ equity
Net Loss Per Share Attributable to Vertex Common Stockholders	Net Loss Per Share Attributable to Vertex Common Shareholders Basic and diluted net loss per share attributable to Vertex common shareholders are presented in conformity with the two-class method required for participating securities. Under the two-class method, earnings are allocated to (i) Vertex common shares, excluding unvested restricted stock, and (ii) participating securities, based on their respective weighted-average shares outstanding for the period. Shares of unvested restricted stock granted under the Company’s Amended and Restated 2006 Stock and Option Plan have the non-forfeitable right to receive dividends on an equal basis with other outstanding common stock. As a result, these unvested shares of restricted stock are considered participating securities under the two-class method. Potentially dilutive shares result from the assumed exercise of outstanding stock options (the proceeds of which are then assumed to have been used to repurchase outstanding stock using the treasury stock method). Basic net loss per share attributable to Vertex common shareholders is based upon the weighted-average number of common shares outstanding during the period, excluding restricted stock that has been issued but is not yet vested. Diluted net loss per share attributable to Vertex common shareholders is based upon the weighted-average number of common shares outstanding during the period plus additional weighted-average common equivalent shares outstanding during the period when the effect is dilutive.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In 2014, the Financial Accounting Standards Board (“FASB”) issued new guidance applicable to revenue recognition that became effective January 1, 2018. The new guidance applies a more principles based approach to recognizing revenue. Under the new guidance, revenue is recognized when a customer obtains control of promised goods or services and is recognized in an amount that reflects the consideration that an entity expects to receive in exchange for those goods or services. In addition, the standard requires disclosure of the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. The new guidance must be adopted using either a modified retrospective approach or a full retrospective approach for all periods presented. Under the modified retrospective method, the cumulative effect of applying the standard would be recognized at the date of initial application within accumulated deficit. Under the full retrospective approach, the standard would be applied to each prior reporting period presented. Upon adoption, the Company will use the modified retrospective method. The Company has evaluated the new guidance and the effect the adoption will have on the consolidated financial statements. The Company’s project team has finalized its review of existing customer contracts and current accounting policies and has concluded that the following will be impacted by applying the requirements of the new standard beginning in the first quarter of 2018: • The Company will be required to estimate the amount of consideration it expects to retain on shipments of ORKAMBI under early access programs in France whereby the associated product has received regulatory approval but the price is not fixed or determinable based on the status of ongoing pricing discussions as of December 31, 2017. Please refer to “Product Revenues, Net” above for further information related to the impact of the new revenue recognition on these sales. • The Company expects to recognize $6.5 million that was received with the sale of its HIV protease inhibitor royalty stream in 2008 net of deferred costs associated with this sale as a cumulative effect adjustment to its accumulated deficit due to the new revenue recognition guidance. Please refer to “Royalty Revenues” above and Note O, “Other Arrangements” for further information related to this transaction. The Company has implemented appropriate changes to its internal controls to support revenue recognition and additional revenue-related disclosures under the new standard. In 2016, the FASB issued amended guidance applicable to share-based compensation to employees that simplifies the accounting for employee share-based payment transactions, including the accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as classification in the statement of cash flows. The amended guidance became effective for the Company January 1, 2017. The amended guidance eliminates the requirement that excess tax benefits be realized as a reduction in current taxes payable before the associated tax benefit can be recognized as an increase in additional paid-in capital. This created approximately $410.8 million of deferred tax asset (“DTA”) relating to federal and state net operating losses (“NOLs”) that are fully reserved by an equal increase in valuation allowance. The Company recorded DTAs of approximately $404.7 million relating to federal NOLs and approximately $6.1 million relating to state NOLs, both of which are offset by a full valuation allowance. Upon adoption, the Company also elected to change its accounting policy to account for forfeitures of options and awards as they occur. The change was applied on a modified retrospective basis with a cumulative effect adjustment to the Company’s accumulated deficit of $9.4 million , which increased the accumulated deficit as of January 1, 2017. This change also resulted in an increase to the DTA of $3.4 million , which is offset by a full valuation allowance. As a result, there was no cumulative effect adjustment to accumulated deficit related to income taxes. The provisions related to the recognition of excess tax benefits in the income statement and classification in the statement of cash flows were adopted prospectively, and as such, the prior periods were not retrospectively adjusted. In 2016, the FASB issued amended guidance related to the recording of financial assets and financial liabilities. Under the amended guidance, equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) are to be measured at fair value with changes in fair value recognized in net income (loss). However, an entity has the option to either measure equity investments without readily determinable fair values either (i) at fair value or (ii) at cost adjusted for changes in observable prices minus impairment. Changes in measurement under either alternative will be recognized in net income (loss). The amended guidance became effective January 1, 2018. The Company held publicly traded equity investments as well as equity investments accounted for under the cost method as of December 31, 2017 . In the first quarter of 2018, the Company will record a cumulative effect adjustment to its accumulated deficit equal to the $25.1 million unrealized gain, net of tax, recorded in accumulated other comprehensive income (loss) as of December 31, 2017 related to its publicly traded equity investments. This adjustment will decrease the Company’s accumulated deficit as of January 1, 2018. Adoption of the amended guidance will have no effect on the Company’s equity investments accounted for under the cost method because there have been no changes in observable prices or impairments identified that would adjust the cost of the investment as of December 31, 2017 compared to the original cost basis of these investments. The implementation of this amended guidance is expected to increase volatility in net income as the volatility currently recorded in other comprehensive income (loss) related to changes in the fair market value of equity investments will be reflected in net income (loss) after adoption. In 2016, the FASB issued amended guidance applicable to leases that will be effective for the year ending December 31, 2019. Early adoption is permitted. This guidance requires entities to recognize assets and liabilities for leases with lease terms of more than 12 months on the balance sheet and requires a modified retrospective adoption approach. The Company is in the process of evaluating this guidance and determining the expected effect on its consolidated financial statements; however, it anticipates that the amended guidance will result in the Company recording additional assets and corresponding liabilities on its consolidated balance sheets. The Company expects the implementation of the new standard will have an impact on its internal controls, systems, and processes. In 2016, the FASB issued amended guidance related to intra-entity transfers other than inventory. This guidance removes the current exception in GAAP prohibiting entities from recognizing current and deferred income tax expenses or benefits related to transfer of assets, other than inventory, within the consolidated entity. The current exception to defer the recognition of any tax impact on the transfer of inventory within the consolidated entity until it is sold to a third party remains unaffected. The amended guidance became effective for the Company on January 1, 2018. In the first quarter of 2018, the Company will record a deferred tax asset and corresponding full valuation allowance upon adoption of this new guidance equal to the unamortized cost of intellectual property transferred to the United Kingdom (“U.K.”) in 2014 multiplied by appropriate statutory rates. As a result, there will be no cumulative effect adjustment to accumulated deficit. In 2017, the FASB issued amended guidance related to business combinations. The amended guidance clarifies the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The new accounting guidance is effective for annual periods beginning after December 15, 2017, including interim periods within those periods. The Company early adopted this new guidance as of January 1, 2017 and has applied this new guidance to acquisitions completed subsequent to adoption. In 2017, the FASB issued amended guidance related to measurements of goodwill. The amended guidance eliminates a step from the goodwill impairment test. Under the amended guidance, an entity should perform its annual or interim goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity would recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. The amended guidance is effective for the year-ending December 31, 2020. Early adoption is permitted. The Company does not expect a significant effect on its consolidated financial statements upon adoption of this new guidance. In 2017, the FASB issued amended guidance related to the scope of stock option modification accounting, to reduce diversity in practice and provide clarity regarding existing guidance. The new accounting guidance became effective January 1, 2018. The Company does not expect the adoption of this guidance to have a material effect on its consolidated financial statements and related disclosures. In 2017, the FASB issued amended guidance applicable to hedge accounting. The new accounting guidance is effective for annual periods beginning after December 15, 2018, including interim periods within those periods. Early adoption is permitted. The amended guidance helps simplify certain aspects of hedge accounting and enables entities to more accurately present their risk management activities in their financial statements. The Company is in the process of evaluating this guidance and determining the expected effect on its consolidated financial statements.

Nature of Business and Accoun31

Nature of Business and Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Schedule of product revenues allowances and reserve categories	The following table summarizes activity in each of the product revenue allowance and reserve categories for the three years ended December 31, 2017 : Trade Rebates, Product Other Total (in thousands) 2017 Beginning Balance $ 2,568 $ 81,927 $ 3,492 $ 1,214 $ 89,201 Provision related to current period sales 25,892 176,996 4,038 15,595 222,521 Adjustments related to prior period sales (189 ) (8,943 ) (13 ) (493 ) (9,638 ) Credits/payments made (25,507 ) (137,765 ) (4,496 ) (11,633 ) (179,401 ) Ending Balance $ 2,764 $ 112,215 $ 3,021 $ 4,683 $ 122,683 2016 Beginning Balance $ 2,089 $ 44,669 $ 1,228 $ 1,310 $ 49,296 Provision related to current period sales 20,075 134,198 3,047 6,602 163,922 Adjustments related to prior period sales (90 ) 154 (17 ) (151 ) (104 ) Credits/payments made (19,506 ) (97,094 ) (766 ) (6,547 ) (123,913 ) Ending Balance $ 2,568 $ 81,927 $ 3,492 $ 1,214 $ 89,201 2015 Beginning Balance $ 1,463 $ 29,102 $ 4,713 $ 745 $ 36,023 Provision related to current period sales 10,890 65,781 779 3,755 81,205 Adjustments related to prior period sales (214 ) (19,410 ) (993 ) (235 ) (20,852 ) Credits/payments made (10,050 ) (30,804 ) (3,271 ) (2,955 ) (47,080 ) Ending Balance $ 2,089 $ 44,669 $ 1,228 $ 1,310 $ 49,296

Collaborative Arrangements (Tab

Collaborative Arrangements (Tables)	12 Months Ended
	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of collaborative arrangement activity net loss attributable to noncontrolling interest	An aggregate summary of net loss attributable to noncontrolling interest related to the Company’s VIEs for the three years ended December 31, 2017 was as follows: 2017 2016 2015 (in thousands) Loss attributable to noncontrolling interest before (benefit from) provision for income taxes and changes in fair value of contingent payments $ 223,379 $ 10,086 $ 6,646 (Benefit from) provision for income taxes (114,090 ) 16,743 29,731 Decrease (increase) in fair value of contingent payments 62,560 (54,850 ) (4,530 ) Net loss (income) attributable to noncontrolling interest $ 171,849 $ (28,021 ) $ 31,847
Schedule of changes in fair value of contingent payments	During three years ended December 31, 2017 , the (increases) decreases in the fair value of the contingent payments related to the Company’s VIEs were as follows: 2017 2016 2015 (in thousands) Parion $ 63,460 $ (64,800 ) $ (3,660 ) BioAxone (900 ) 9,950 (870 )
Scheulde of fair value of consideration payments	The fair value of the contingent payments related to the Parion Agreement and the BioAxone Agreement as of the dates set forth in the table were as follows: December 31, 2017 December 31, 2016 (in thousands) Parion $ — $ 238,800 BioAxone 18,900 18,000
Schedule of collaborative arrangement summary of items related to variable interest entities	Amounts as of December 31, 2017 related to BioAxone while amounts as of December 31, 2016 related to Parion and BioAxone. December 31, 2017 December 31, 2016 (in thousands) Restricted cash and cash equivalents (VIE) $ 1,489 $ 47,762 Prepaid expenses and other current assets 22 6,812 Intangible assets 29,000 284,340 Other assets 256 399 Accounts payable 1,021 415 Taxes payable 2,171 1,330 Other current liabilities — 2,137 Deferred tax liability, net 4,756 131,446 Other liabilities — 300 Noncontrolling interest 13,727 181,609

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Schedule of earning per share, basic and diluted, by common shares	The following table sets forth the computation of basic and diluted net income (loss) per share for three years ended December 31, 2017 : 2017 2016 2015 (in thousands, except per share amounts) Basic net income (loss) attributable to Vertex per common share calculation: Net income (loss) attributable to Vertex common shareholders $ 263,484 $ (112,052 ) $ (556,334 ) Less: Undistributed earnings allocated to participating securities (293 ) — — Net income (loss) attributable to Vertex common shareholders—basic $ 263,191 $ (112,052 ) $ (556,334 ) Basic weighted-average common shares outstanding 248,858 244,685 241,312 Basic net income (loss) attributable to Vertex per common share $ 1.06 $ (0.46 ) $ (2.31 ) Diluted net income (loss) attributable to Vertex per common share calculation: Net income (loss) attributable to Vertex common shareholders $ 263,484 $ (112,052 ) $ (556,334 ) Less: Undistributed earnings allocated to participating securities (288 ) — — Net income (loss) attributable to Vertex common shareholders—diluted $ 263,196 $ (112,052 ) $ (556,334 ) Weighted-average shares used to compute basic net income (loss) per common share 248,858 244,685 241,312 Effect of potentially dilutive securities: Stock options 2,797 — — Restricted stock and restricted stock units (including PSUs) 1,542 — — Employee stock purchase plan 28 — — Weighted-average shares used to compute diluted net income (loss) per common share 253,225 244,685 241,312 Diluted net income (loss) attributable to Vertex per common share $ 1.04 $ (0.46 ) $ (2.31 )
Schedule of antidilutive securities excluded from computation of earnings per share	The Company did not include the securities in the following table in the computation of the net income (loss) per share attributable to Vertex common shareholders calculations because the effect would have been anti-dilutive during each period. 2017 2016 2015 (in thousands) Stock options 3,554 12,642 11,145 Unvested restricted stock and restricted stock units (including PSUs) 411 3,546 3,024

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Financial assets and liabilities subject to fair value measurements (excluding restricted cash and cash equivalents (VIE))	The following table sets forth the Company’s financial assets and liabilities (excluding VIE cash and cash equivalents) subject to fair value measurements: Fair Value Measurements as Fair Value Hierarchy Total Level 1 Level 2 Level 3 (in thousands) Financial instruments carried at fair value (asset position): Cash equivalents: Money market funds $ 614,951 $ 614,951 $ — $ — Government-sponsored enterprise securities 12,678 12,678 — — Commercial paper 57,357 — 57,357 — Marketable securities: Corporate equity securities 74,821 74,821 — — Government-sponsored enterprise securities 2,303 2,303 — — Corporate debt securities 265,867 — 265,867 — Commercial paper 80,263 — 80,263 — Prepaid and other current assets: Foreign currency forward contracts 13 — 13 — Total financial assets $ 1,108,253 $ 704,753 $ 403,500 $ — Financial instruments carried at fair value (liability position): Other liabilities, current portion: Foreign currency forward contracts $ (13,642 ) $ — $ (13,642 ) $ — Other liabilities, excluding current portion: Foreign currency forward contracts (866 ) — (866 ) — Total financial liabilities $ (14,508 ) $ — $ (14,508 ) $ — Fair Value Measurements as Fair Value Hierarchy Total Level 1 Level 2 Level 3 (in thousands) Financial instruments carried at fair value (asset position): Cash equivalents: Money market funds $ 280,560 $ 280,560 $ — $ — Marketable securities: Corporate equity securities 64,560 64,560 — — Government-sponsored enterprise securities 15,508 15,508 — — Corporate debt securities 111,140 — 111,140 — Commercial paper 59,404 — 59,404 — Prepaid and other current assets: Foreign currency forward contracts 14,407 — 14,407 — Other assets: Foreign currency forward contracts 1,186 — 1,186 — Total financial assets $ 546,765 $ 360,628 $ 186,137 $ — Financial instruments carried at fair value (liability position): Other liabilities, current portion: Foreign currency forward contracts $ (144 ) $ — $ (144 ) $ — Total financial liabilities $ (144 ) $ — $ (144 ) $ —

Marketable Securities (Tables)

Marketable Securities (Tables)	12 Months Ended
	Dec. 31, 2017
Cash and Cash Equivalents [Abstract]
Summary of cash, cash equivalents and marketable securities	A summary of the Company’s cash, cash equivalents and marketable securities is shown below: Amortized Cost Gross Gross Fair Value (in thousands) December 31, 2017 Cash and cash equivalents: Cash and money market funds $ 1,595,377 $ — $ — $ 1,595,377 Government-sponsored enterprise securities 12,679 — (1 ) 12,678 Commercial paper 57,371 — (14 ) 57,357 Total cash and cash equivalents $ 1,665,427 $ — $ (15 ) $ 1,665,412 Marketable securities: Corporate equity securities $ 43,213 $ 31,608 $ — $ 74,821 Government-sponsored enterprise securities 2,304 — (1 ) 2,303 Corporate debt securities (matures within 1 year) 215,639 — (363 ) 215,276 Corporate debt securities (matures after 1 year through 5 years) 50,697 — (106 ) 50,591 Commercial paper (matures within 1 year) 80,372 — (109 ) 80,263 Total marketable securities 392,225 31,608 (579 ) 423,254 Total cash, cash equivalents and marketable securities $ 2,057,652 $ 31,608 $ (594 ) $ 2,088,666 December 31, 2016 Cash and cash equivalents: Cash and money market funds $ 1,183,945 $ — $ — $ 1,183,945 Total cash and cash equivalents $ 1,183,945 $ — $ — $ 1,183,945 Marketable securities: Corporate equity securities $ 43,213 $ 21,347 $ — $ 64,560 Government-sponsored enterprise securities (matures within 1 year) 15,506 2 — 15,508 Corporate debt securities (matures within 1 year) 111,225 — (85 ) 111,140 Commercial paper (matures within 1 year) 59,331 73 — 59,404 Total marketable securities 229,275 21,422 (85 ) 250,612 Total cash, cash equivalents and marketable securities $ 1,413,220 $ 21,422 $ (85 ) $ 1,434,557

Accumulated Other Comprehensi36

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Schedule of Reclassifications out of Accumulated Other Comprehensive Income (Loss)	The following table summarizes the changes in accumulated other comprehensive income (loss) by component: Foreign currency translation adjustment Unrealized holding gains (losses) on marketable securities, net of tax Unrealized (losses) gains on foreign currency forward contracts, net of tax Total (in thousands) Balance at December 31, 2014 $ (971 ) $ (123 ) $ 2,011 $ 917 Other comprehensive (loss) income before reclassifications (1,109 ) 249 6,493 5,633 Amounts reclassified from accumulated other comprehensive income (loss) — — (4,726 ) (4,726 ) Net current period other comprehensive (loss) income (1,109 ) 249 1,767 907 Balance at December 31, 2015 $ (2,080 ) $ 126 $ 3,778 $ 1,824 Other comprehensive (loss) income before reclassifications (5,782 ) 17,395 17,383 28,996 Amounts reclassified from accumulated other comprehensive income (loss) — — (9,647 ) (9,647 ) Net current period other comprehensive (loss) income (5,782 ) 17,395 7,736 19,349 Balance at December 31, 2016 $ (7,862 ) $ 17,521 $ 11,514 $ 21,173 Other comprehensive (loss) income before reclassifications (13,169 ) 6,954 (29,175 ) (35,390 ) Amounts reclassified from accumulated other comprehensive income (loss) — — 2,645 2,645 Net current period other comprehensive (loss) income (13,169 ) 6,954 (26,530 ) (32,745 ) Balance at December 31, 2017 $ (21,031 ) $ 24,475 $ (15,016 ) $ (11,572 )

Hedging (Tables)

Hedging (Tables)	12 Months Ended
	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Cash Flow Hedging Instruments	The following table summarizes the notional amount of the Company’s outstanding foreign currency forward contracts designated as cash flow hedges: As of As of December 31, 2017 2016 Foreign Currency (in thousands) Euro $ 257,230 $ 164,368 British pound sterling 77,481 65,237 Australian dollar 30,501 23,776 Total foreign currency forward contracts $ 365,212 $ 253,381
Schedule of Foreign Exchange Contracts	The following table summarizes the fair value of the Company’s outstanding foreign currency forward contracts not designated for hedge accounting under GAAP included on the Company’s consolidated balance sheets: As of December 31, 2017 2016 (in thousands) Prepaid expenses and other current assets $ — $ 660 Other liabilities, current portion 684 — The following table summarizes the fair value of the Company’s outstanding foreign currency forward contracts designated as cash flow hedges under GAAP included on the Company’s consolidated balance sheets: As of December 31, 2017 Assets Liabilities Classification Fair Value Classification Fair Value (in thousands) Prepaid and other current assets $ 13 Other liabilities, current portion $ (13,642 ) Other assets — Other liabilities, excluding current portion (866 ) Total assets $ 13 Total liabilities $ (14,508 ) As of December 31, 2016 Assets Liabilities Classification Fair Value Classification Fair Value (in thousands) Prepaid and other current assets $ 14,407 Other liabilities, current portion $ (144 ) Other assets 1,186 Other liabilities, excluding current portion — Total assets $ 15,593 Total liabilities $ (144 )
Derivatives Offsetting	The following table summarizes the potential effect of offsetting derivatives by type of financial instrument on the Company’s consolidated balance sheets: As of December 31, 2017 Gross Amounts Recognized Gross Amounts Offset Gross Amount Presented Gross Amount Not Offset Legal Offset Foreign currency forward contracts (in thousands) Total assets $ 13 $ — $ 13 $ (13 ) $ — Total liabilities (14,508 ) — (14,508 ) 13 (14,495 ) As of December 31, 2016 Gross Amounts Recognized Gross Amounts Offset Gross Amount Presented Gross Amount Not Offset Legal Offset Foreign currency forward contracts (in thousands) Total assets $ 15,593 $ — $ 15,593 $ (144 ) $ 15,449 Total liabilities (144 ) — (144 ) 144 —

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2017
Inventory Disclosure [Abstract]
Schedule of Inventories by Type	Inventories consisted of the following: As of December 31, 2017 2016 (in thousands) Raw materials $ 20,924 $ 6,348 Work-in-process 74,237 56,672 Finished goods 16,669 14,584 Total $ 111,830 $ 77,604

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Schedule of Property and equipment	Property and equipment, net consisted of the following: As of December 31, 2017 2016 (in thousands) Buildings $ 634,061 $ 548,232 Furniture and equipment 256,509 236,634 Software 151,890 134,321 Leasehold improvements 117,806 108,702 Computers 61,294 58,271 Total property and equipment, gross 1,221,560 1,086,160 Less: accumulated depreciation (432,123 ) (387,798 ) Total property and equipment, net $ 789,437 $ 698,362

Additional Balance Sheet Deta40

Additional Balance Sheet Detail (Tables)	12 Months Ended
	Dec. 31, 2017
Payables and Accruals [Abstract]
Summary of Prepaid and other current assets	Prepaid and other current assets consisted of the following: As of December 31, 2017 2016 (in thousands) Prepaid expenses $ 62,475 $ 36,134 Collaborative accounts receivable 28,907 719 Other receivables and assets 74,253 34,400 Total $ 165,635 $ 71,253
Summary of Accrued expenses and other current liabilities	Accrued expenses consisted of the following: As of December 31, 2017 2016 (in thousands) Payroll and benefits $ 113,026 $ 86,387 Research, development and commercial contract costs 98,411 62,756 Product revenue allowances 119,919 86,533 Royalty payable 73,044 52,845 Other 39,561 26,728 Total $ 443,961 $ 315,249

Common Stock, Preferred Stock41

Common Stock, Preferred Stock and Equity Plans (Tables)	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Schedule of stock and stock equity plans	The following table contains information about the Company’s equity plans: As of December 31, 2017 Title of Plan Group Eligible Type of Award Awards Additional Awards 2013 Stock and Option Plan Employees, Non-employee Directors and Consultants NSO, 10,388,723 11,427,114 2006 Stock and Option Plan Employees, Non-employee Directors and Consultants NSO, 3,102,768 — Total 13,491,491 11,427,114
Outstanding and vested options	The following table summarizes information related to the outstanding and exercisable options during the year ended December 31, 2017 : Stock Options Weighted-average Weighted-average Aggregate Intrinsic (in thousands) (per share) (in years) (in thousands) Outstanding at December 31, 2016 12,642 $ 81.41 Granted 2,359 $ 108.43 Exercised (4,561 ) $ 70.90 Forfeited (611 ) $ 99.53 Expired (62 ) $ 105.24 Outstanding at December 31, 2017 9,767 $ 91.57 6.95 $ 585,293 Exercisable at December 31, 2017 5,313 $ 80.14 5.75 $ 375,472
Stock options outstanding and exercisable	The following table summarizes information about stock options outstanding and exercisable at December 31, 2017 : Options Outstanding Options Exercisable Range of Exercise Prices Number Weighted-average Weighted-average Number Weighted-average (in thousands) (in years) (per share) (in thousands) (per share) $18.93–$20.00 128 0.10 $ 18.93 128 $ 18.93 $20.01–$40.00 810 1.88 $ 34.43 810 $ 34.43 $40.01–$60.00 798 4.49 $ 49.15 798 $ 49.15 $60.01–$80.00 746 6.19 $ 75.49 653 $ 75.40 $80.01–$100.00 4,350 8.07 $ 89.31 1,514 $ 89.51 $100.01–$120.00 1,087 7.11 $ 109.34 633 $ 109.24 $120.01–$140.00 1,223 7.63 $ 130.20 734 $ 129.89 $140.01–$160.00 — — $ — — $ — $160.01–$163.74 625 9.54 $ 162.94 43 $ 162.94 Total 9,767 6.95 $ 91.57 5,313 $ 80.14
Restricted stock and restricted stock units activity	The following table summarizes the restricted stock and restricted stock unit activity of the Company during the year ended December 31, 2017 : Restricted Stock Restricted Stock Units (excluding PSUs) Number of Units Weighted-average Number of Shares Weighted-average (in thousands) (per share) (in thousands) (per share) Unvested at December 31, 2016 2,613 $ 102.54 798 $ 92.62 Granted — $ — 1,719 $ 113.13 Vested (1,206 ) $ 102.99 (278 ) $ 94.72 Cancelled (178 ) $ 102.45 (228 ) $ 97.86 Unvested at December 31, 2017 1,229 $ 102.12 2,011 $ 109.27
PSU activity	The following table summarizes the PSU activity of the Company during the year ended December 31, 2017 : Performance-Based RSU Number of Units Weighted-average (in thousands) (per share) Unvested at December 31, 2016 (1) 135 $ 91.05 Granted (2) 392 $ 86.71 Vested (15 ) $ 91.05 Cancelled (28 ) $ 86.52 Unvested at December 31, 2017 484 $ 87.59 (1) Represents the Company’s 2016 PSUs based on the target number of shares issuable at the end of each of the financial and non-financial performance periods. (2) Represents (i) the target number of shares issuable for the Company’s 2017 PSUs at the end of each of the financial and non-financial performance periods and (ii) a decrease in shares issuable under 2016 PSUs based on 2016 financial performance.
Shares issued under Employee Stock Purchase Plan	In 2017 , the following shares were issued to employees under the ESPP: Year Ended December 31, 2017 (in thousands, Number of shares 275 Average price paid per share $ 80.71

Stock-based Compensation Expe42

Stock-based Compensation Expense (Tables)	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-based compensation expense by line item	The effect of stock-based compensation expense during the three years ended December 31, 2017 was as follows: 2017 2016 2015 (in thousands) Stock-based compensation expense by line item: Research and development expenses $ 181,900 $ 153,451 $ 152,955 Sales, general and administrative expenses 108,836 84,254 78,070 Total stock-based compensation expense included in costs and expenses $ 290,736 $ 237,705 $ 231,025
Stock-based compensation expense by type of award	The stock-based compensation expense by type of award during the three years ended December 31, 2017 was as follows: 2017 2016 2015 (in thousands) Stock-based compensation expense by type of award: Stock options $ 105,367 $ 114,768 $ 129,276 Restricted stock and restricted stock units (including PSUs) 181,258 118,709 98,811 ESPP share issuances 9,017 7,835 7,025 Less: stock-based compensation expense capitalized to inventories (4,906 ) (3,607 ) (4,087 ) Total stock-based compensation expense included in costs and expenses $ 290,736 $ 237,705 $ 231,025
Unrecognized stock-based compensation expense, net of estimated forfeitures	The following table sets forth the Company’s unrecognized stock-based compensation expense as of December 31, 2017 , by type of award and the weighted-average period over which that expense is expected to be recognized: As of December 31, 2017 Unrecognized Expense Weighted-average Recognition Period (in thousands) (in years) Type of award: Stock options $ 147,402 2.45 Restricted stock and restricted stock units (including PSUs) $ 254,302 2.47 ESPP share issuances $ 4,245 0.59
Schedule of assumptions used to estimate the grant date fair value of options	The fair value of each option granted during 2017 , 2016 and 2015 was estimated on the date of grant using the Black-Scholes option pricing model with the following weighted-average assumptions: 2017 2016 2015 Expected stock price volatility 45.31 % 46.77 % 47.29 % Risk-free interest rate 1.94 % 1.32 % 1.61 % Expected term of options (in years) 4.68 4.91 5.28 Expected annual dividends — — —
Schedule of assumptions used to estimate the grant date fair value employee stock purchase plan	The following table reflects the weighted-average assumptions used in the Black-Scholes option pricing model for 2017 , 2016 and 2015 : 2017 2016 2015 Expected stock price volatility 39.09 % 48.22 % 47.20 % Risk-free interest rate 1.24 % 0.56 % 0.40 % Expected term (in years) 0.75 0.75 0.72 Expected annual dividends — — —

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Schedule of components of income (loss) before provision for (benefit from) income taxes	The components of loss before provision for (benefit from) income taxes during the three years ended December 31, 2017 consisted of the following: 2017 2016 2015 (in thousands) United States $ 330,340 $ (147,860 ) $ (272,326 ) Foreign (346,029 ) 80,494 (285,474 ) Loss before (benefit from) provision for income taxes $ (15,689 ) $ (67,366 ) $ (557,800 )
Schedule of components of provision for (benefit from) income taxes	The components of the provision for (benefit from) income taxes during the three years ended December 31, 2017 consisted of the following: 2017 2016 2015 (in thousands) Current taxes: United States $ 11,559 $ (3,821 ) $ 25,623 Foreign 3,576 1,794 831 State 5,025 1,836 3,629 Total current taxes $ 20,160 $ (191 ) $ 30,083 Deferred taxes: United States $ (113,805 ) $ 18,659 $ 497 Foreign (3,222 ) (3,359 ) (355 ) State (10,457 ) 1,556 156 Total deferred taxes $ (127,484 ) $ 16,856 $ 298 (Benefit from) provision for income taxes $ (107,324 ) $ 16,665 $ 30,381
Reconciliation of the provision for (benefit from) income taxes	A reconciliation of the provision for (benefit from) income taxes as computed by applying the U.S. federal statutory rate of 35% to the provision for (benefit from) income taxes during the three years ended December 31, 2017 is as follows: 2017 2016 2015 (in thousands) Loss before (benefit from) provision for income taxes $ (15,689 ) $ (67,366 ) $ (557,800 ) Expected benefit from income taxes (5,491 ) (23,578 ) (195,230 ) State taxes, net of federal benefit 4,742 3,621 3,800 Foreign income tax rate differential 77,801 21,346 47,402 Tax credits (49,088 ) (47,773 ) (55,696 ) Provision for (benefit from) income taxes attributable to valuation allowances (584,917 ) 14,837 226,169 Permanent items 21,825 24,749 5,817 Rate change 575,192 12,836 (1,224 ) Stock compensation (benefit) shortfalls and cancellations (21,453 ) 4,162 951 Tax attribute expiration — 9,947 — Deconsolidation of VIE (126,183 ) — — Other 248 (3,482 ) (1,608 ) (Benefit from) provision for income taxes $ (107,324 ) $ 16,665 $ 30,381
Schedule of deferred tax assets and liabilities	The components of the deferred taxes were as follows: As of December 31, 2017 2016 (in thousands) Deferred tax assets: Net operating loss $ 1,004,404 $ 1,232,399 Tax credit carryforwards 440,429 367,402 Intangible assets 54,091 34,938 Deferred revenues 19,593 31,205 Stock-based compensation 83,196 110,446 Inventories 4,250 4,705 Accrued expenses 17,808 23,078 Construction financing lease obligation 109,354 177,735 Other 1,417 27 Gross deferred tax assets 1,734,542 1,981,935 Valuation allowance (1,552,942 ) (1,731,186 ) Total deferred tax assets 181,600 250,749 Deferred tax liabilities: Property and equipment (101,019 ) (169,089 ) Acquired intangibles (6,341 ) (134,063 ) Deferred revenue (73,357 ) (73,357 ) Unrealized gain (6,401 ) (7,967 ) Net deferred tax liabilities $ (5,518 ) $ (133,727 )

Restructuring Expenses (Tables)

Restructuring Expenses (Tables)	12 Months Ended
	Dec. 31, 2017
Restructuring and Related Activities [Abstract]
Activity related to the restructuring liability	The restructuring charge and other activities related to this restructuring event recorded during the year ended December 31, 2017 were as follows: 2017 (in thousands) Liability, beginning of the period $ — Restructuring expense 12,503 Cash payments (8,602 ) Asset impairments and other non-cash items (1,812 ) Liability, end of the period $ 2,089

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Future minimum commitments under Fan Pier Leases and facility operating leases with terms of more than one year, net of estimated sublease income	As of December 31, 2017 , future minimum commitments under the facility leases with initial terms of more than one year were as follows: Year Fan Pier San Diego Leases Other Total Lease (in thousands) 2018 $ 61,606 $ 2,979 $ 19,866 $ 84,451 2019 72,589 5,324 15,002 92,915 2020 72,589 9,127 13,956 95,672 2021 72,589 9,127 12,163 93,879 2022 72,589 9,127 11,542 93,258 Thereafter 462,442 129,394 57,949 649,785 Total minimum lease payments $ 814,404 $ 165,078 $ 130,478 $ 1,109,960 As of December 31, 2017 , the Company’s total sublease income to be received related to its facility leases was $6.0 million , all of which relates to subleases expiring in 2018.
Schedule of future minimum lease payments for capital leases	The following table sets forth the Company’s future minimum payments due under capital leases as of December 31, 2017 : Year (in thousands) 2018 $ 24,004 2019 10,252 2020 5,434 2021 3,676 2022 1,706 Thereafter 387 Total payments 45,459 Less: amount representing interest (2,432 ) Present value of payments $ 43,027

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Revenues by Product	Product revenues, net consisted of the following: 2017 2016 2015 (in thousands) ORKAMBI $ 1,320,850 $ 979,590 $ 350,663 KALYDECO 844,630 703,432 631,674 INCIVEK — 610 17,987 Total product revenues, net $ 2,165,480 $ 1,683,632 $ 1,000,324
Revenues and Property and Equipment by Location	Property and equipment, net by location consisted of the following: As of December 31, 2017 2016 (in thousands) United States $ 753,128 $ 665,552 Outside of the United States United Kingdom 31,279 26,921 Other 5,030 5,889 Total property and equipment, net outside of the United States 36,309 32,810 Total property and equipment, net $ 789,437 $ 698,362 Total revenues from external customers and collaborators by geographic region consisted of the following: 2017 2016 2015 (in thousands) United States $ 1,986,786 $ 1,321,807 $ 763,316 Outside of the United States Europe 420,317 320,456 219,596 Other 81,549 59,914 49,424 Total revenues outside of the United States 501,866 380,370 269,020 Total revenues $ 2,488,652 $ 1,702,177 $ 1,032,336
Significant Customers	Gross revenues and accounts receivable from each of the Company’s customers who individually accounted for 10% or more of total gross revenues and/or 10% or more of total gross accounts receivable consisted of the following: Percent of Total Gross Revenues Percent of Gross Accounts Receivable Year Ended December 31, As of December 31, 2017 2016 2015 2017 2016 Walgreen Co. 17 % 19 % 20 % 20 % 15 % Accredo/Curascript 14 % 15 % 15 % 12 % 10 % CVS/Caremark <10 % 19 % 17 % n/a 17 %

Quarterly Financial Data (una47

Quarterly Financial Data (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Schedule of quarterly financial data	The following table sets forth the Company’s quarterly financial data for the two years ended December 31, 2017 . Three Months Ended March 31, June 30, September 30, December 31, (in thousands, except per share amounts) Revenues: Product revenues, net $ 480,622 $ 513,988 $ 549,642 $ 621,228 Royalty revenues 1,551 2,861 2,231 1,345 Collaborative revenues (1) 232,545 27,286 26,292 29,061 Total revenues 714,718 544,135 578,165 651,634 Costs and expenses: Cost of product revenues 46,242 70,535 72,186 83,712 Royalty expenses 746 670 688 340 Research and development expenses (2) 273,563 289,451 454,947 306,664 Sales, general and administrative expenses 113,326 127,249 120,710 134,794 Restructuring expenses 9,999 3,523 337 387 Intangible asset impairment charge (3) — — 255,340 — Total costs and expenses 443,876 491,428 904,208 525,897 Income (loss) from operations 270,842 52,707 (326,043 ) 125,737 Interest expense, net (16,765 ) (14,664 ) (13,574 ) (12,547 ) Other expense, net (3) (544 ) (2,537 ) (77,553 ) (748 ) Income (loss) before provision for (benefit from) income taxes 253,533 35,506 (417,170 ) 112,442 Provision for (benefit from) income taxes (3) 3,985 4,337 (125,903 ) 10,257 Net income (loss) 249,548 31,169 (291,267 ) 102,185 (Income) loss attributable to noncontrolling interest (3) (1,792 ) (13,173 ) 188,315 (1,501 ) Net income (loss) attributable to Vertex $ 247,756 $ 17,996 $ (102,952 ) $ 100,684 Amounts per share attributable to Vertex common shareholders: Net income (loss): Basic $ 1.01 $ 0.07 $ (0.41 ) $ 0.40 Diluted $ 0.99 $ 0.07 $ (0.41 ) $ 0.39 Shares used in per share calculations: Basic 246,024 247,521 250,268 251,557 Diluted 248,700 251,635 250,268 256,804 Three Months Ended March 31, June 30, September 30, December 31, (in thousands, except per share amounts) Revenues: Product revenues, net $ 394,410 $ 425,651 $ 409,689 $ 453,882 Royalty revenues 3,596 5,282 3,835 3,887 Collaborative revenues 74 675 259 937 Total revenues 398,080 431,608 413,783 458,706 Costs and expenses: Cost of product revenues 49,789 44,154 53,222 59,646 Royalty expenses 860 1,098 855 836 Research and development expenses (4) 255,860 271,008 272,370 248,452 Sales, general and administrative expenses 105,214 111,652 106,055 109,908 Restructuring expenses 687 343 8 224 Total costs and expenses 412,410 428,255 432,510 419,066 (Loss) income from operations (14,330 ) 3,353 (18,727 ) 39,640 Interest expense, net (20,698 ) (20,155 ) (20,140 ) (20,439 ) Other income (expense), net 4,411 (1,219 ) (167 ) 1,105 (Loss) income before provision for (benefit from) income taxes (30,617 ) (18,021 ) (39,034 ) 20,306 Provision for (benefit from) income taxes 5,485 18,130 503 (7,453 ) Net (loss) income (36,102 ) (36,151 ) (39,537 ) 27,759 (Income) loss attributable to noncontrolling interest (5,529 ) (28,374 ) 696 5,186 Net (loss) income attributable to Vertex $ (41,631 ) $ (64,525 ) $ (38,841 ) $ 32,945 Amounts per share attributable to Vertex common shareholders: Net (loss) income: Basic $ (0.17 ) $ (0.26 ) $ (0.16 ) $ 0.13 Diluted $ (0.17 ) $ (0.26 ) $ (0.16 ) $ 0.13 Shares used in per share calculations: Basic 243,831 244,482 244,920 245,454 Diluted 243,831 244,482 244,920 247,757 1. In the first quarter of 2017, the Company recognized $230.0 million of collaborative revenues related to an upfront payment from Merck KGaA pursuant to the Company’s collaboration with Merck KGaA. In each of the second and third quarters of 2017, the Company recognized $20.0 million of collaborative revenues related to payments that Parion, which was a variable interest entity during these periods, received from Shire pursuant to a license agreement. In the fourth quarter of 2017, the Company recognized $25.0 million of collaborative revenues related to a milestone achieved pursuant to its license agreement with Janssen Inc. pursuant to which Janssen is developing JNJ-63623872 for the treatment of influenza. See Note B, “ Collaborative Arrangements and Acquisitions, ” for further information. 2. In the third quarter of 2017, the Company incurred research and development expenses of approximately $160.0 million to acquire certain CF assets including VX-561 from Concert. See Note B, “ Collaborative Arrangements and Acquisitions, ” for further information. 3. In the third quarter of 2017, the Company recorded a $255.3 million intangible asset impairment charge related to Parion’s pulmonary ENaC platform indefinite-lived in-process research and development asset, a decrease in the fair value of the contingent payments payable by the Company to Parion of $69.6 million and benefit from income taxes of $126.2 million resulting from these charges. These charges and benefit from income taxes were attributable to noncontrolling interest. See Note B, “ Collaborative Arrangements and Acquisitions, ” and Note J, “Intangible Assets and Goodwill,” for further information. 4. In the second quarter of 2016, the Company incurred research and development expenses of approximately $10.0 million to acquire certain early-stage research assets. In the third quarter of 2016, the Company incurred research and development expenses related to a $20.0 million upfront payment to Moderna Therapeutics, Inc. See Note B, “ Collaborative Arrangements and Acquisitions, ” for further information.

Nature of Business and Accoun48

Nature of Business and Accounting Policies - Business Narrative (Details) $ in Billions	12 Months Ended
	Dec. 31, 2017USD ($)segment
Accounting Policies [Abstract]
Cash, cash equivalents and marketable securities | $	$ 2.1
Number of operating segments | segment	1

Nature of Business and Accoun49

Nature of Business and Accounting Policies - Revenue Recognition (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Accounts receivable, discount period	30 days
Activity related to product revenues allowances and reserve categories
Beginning Balance	$ 89,201	$ 49,296	$ 36,023
Provision related to current period sales	222,521	163,922	81,205
Adjustments related to prior period sales	(9,638)	(104)	(20,852)
Credits/payments made	(179,401)	(123,913)	(47,080)
Ending Balance	$ 122,683	89,201	49,296
Prior period adjustment as total percent of net product revenues (less than)	0.50%
Customer deposits	$ 232,401	73,416
New accounting pronouncement or change in accounting principle, cumulative effect of change on equity or net assets	6,500
Trade Allowances
Activity related to product revenues allowances and reserve categories
Beginning Balance	2,568	2,089	1,463
Provision related to current period sales	25,892	20,075	10,890
Adjustments related to prior period sales	(189)	(90)	(214)
Credits/payments made	(25,507)	(19,506)	(10,050)
Ending Balance	2,764	2,568	2,089
Rebates, Chargebacks and Discounts
Activity related to product revenues allowances and reserve categories
Beginning Balance	81,927	44,669	29,102
Provision related to current period sales	176,996	134,198	65,781
Adjustments related to prior period sales	(8,943)	154	(19,410)
Credits/payments made	(137,765)	(97,094)	(30,804)
Ending Balance	112,215	81,927	44,669
Product Returns
Activity related to product revenues allowances and reserve categories
Beginning Balance	3,492	1,228	4,713
Provision related to current period sales	4,038	3,047	779
Adjustments related to prior period sales	(13)	(17)	(993)
Credits/payments made	(4,496)	(766)	(3,271)
Ending Balance	3,021	3,492	1,228
Other Incentives
Activity related to product revenues allowances and reserve categories
Beginning Balance	1,214	1,310	745
Provision related to current period sales	15,595	6,602	3,755
Adjustments related to prior period sales	(493)	(151)	(235)
Credits/payments made	(11,633)	(6,547)	(2,955)
Ending Balance	$ 4,683	$ 1,214	$ 1,310

Nature of Business and Accoun50

Nature of Business and Accounting Policies - Share-Based Compensation (Details)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Percentage of employees eligible for acceleration of equity awards (less than) (percent)	5.00%

Nature of Business and Accoun51

Nature of Business and Accounting Policies - Advertising Expenses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Advertising expense	$ 35.2	$ 31.4	$ 24.5

Nature of Business and Accoun52

Nature of Business and Accounting Policies - Property and Equipment (Details)	12 Months Ended
	Dec. 31, 2017
Furniture and equipment | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment useful life	7 years
Furniture and equipment | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment useful life	10 years
Computers and software | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment useful life	3 years
Computers and software | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment useful life	5 years
Buildings and leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment useful life	40 years

Nature of Business and Accoun53

Nature of Business and Accounting Policies Nature of Business and Accounting Policies - Variable Interest Entities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Restricted cash and cash equivalents (VIE)	$ 1,489	$ 47,762

Nature of Business and Accoun54

Nature of Business and Accounting Policies - Foreign Currency Gain (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Derivative term (less than)	1 month
Foreign Currency Translation
Net unrealized losses related to foreign currency translation	$ (21)	$ (7.9)	$ (2.1)
Net foreign currency transaction gain (loss)	$ 5.5	$ 4	$ (6.8)

Nature of Business and Accoun55

Nature of Business and Accounting Policies - Recent Accounting Pronouncements (Details) - USD ($)	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New accounting pronouncement or change in accounting principle, cumulative effect of change on equity or net assets	$ 6,500,000
Cumulative effect adjustment for adoption of new accounting guidance			$ 0
Accounting standards update 2016-09, excess tax benefit
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating loss carryforwards		$ 410,800,000
Deferred income tax assets, net			3,400,000
Domestic Tax Authority | Accounting standards update 2016-09, excess tax benefit
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating loss carryforwards		404,700,000
State and Local Jurisdiction
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating loss carryforwards	880,700,000
State and Local Jurisdiction | Accounting standards update 2016-09, excess tax benefit
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating loss carryforwards		$ 6,100,000
Accumulated Deficit | Accounting standards update 2016-09, forfeiture rate component
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment for adoption of new accounting guidance			$ (9,371,000)
Accumulated Deficit | Accounting standards update 2016-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment for adoption of new accounting guidance	0
Accumulated Deficit | Accounting standards update 2016-01, financial instruments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment for adoption of new accounting guidance	(25,100,000)
Accumulated Deficit | Accounting standards update 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment for adoption of new accounting guidance	$ 0

Collaborative Arrangements - Cy

Collaborative Arrangements - Cystic Fibrosis Foundation Therapeutics Incorporated (Details) - USD ($)	1 Months Ended	3 Months Ended		12 Months Ended
	Oct. 31, 2016	Mar. 31, 2016	Dec. 31, 2015	Dec. 31, 2017
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Additional milestone payments				$ 0
Cystic Fibrosis Foundation Therapeutics Incorporated
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payments		$ 13,900,000	$ 13,900,000	$ 0
Collaborative funding	$ 75,000,000
Additional collaborative funding	$ 6,000,000

Collaborative Arrangements - CR

Collaborative Arrangements - CRISPR Therapeutics AG (Details)	1 Months Ended		3 Months Ended	12 Months Ended
	Jan. 31, 2018USD ($)	Oct. 31, 2016USD ($)	Jun. 30, 2016USD ($)	Dec. 31, 2015USD ($)target	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Fair Value					$ 2,088,666,000	$ 1,434,557,000
Gross Unrealized Gains					31,608,000	$ 21,422,000
CRISPR Therapeutics
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Right to license, number of targets (up to) | target				6
Collaborative funding				$ 75,000,000
Investment in collaborative partner, pursuant to convertible loan agreement		$ 10,000,000	$ 3,100,000	30,000,000
Collaborative arrangement development and regulatory potential milestone payments maximum				$ 420,000,000
Prior to marketing approval, time period of notice required to terminate (in days)				90 days
Subsequent to marketing approval, time period of notice required to terminate (in days)				270 days
CRISPR Therapeutics | Subsequent Event
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Investment in collaborative partner, pursuant to convertible loan agreement	$ 21,500,000
Common Stock | CRISPR Therapeutics
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Fair Value					74,800,000
Gross Unrealized Gains					$ 31,600,000

Collaborative Arrangements - Me

Collaborative Arrangements - Merck KGaA (Details)

Jan. 10, 2017pre-clinical_stage_programclinical-stage_programdevelopment_program

Dec. 31, 2017USD ($)

Sep. 30, 2017USD ($)

Jun. 30, 2017USD ($)

Mar. 31, 2017USD ($)

Dec. 31, 2016USD ($)

Sep. 30, 2016USD ($)

Jun. 30, 2016USD ($)

Mar. 31, 2016USD ($)

Dec. 31, 2017USD ($)

Dec. 31, 2016USD ($)

Dec. 31, 2015USD ($)

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Collaborative revenues

$ 29,061,000

$ 26,292,000

$ 27,286,000

$ 232,545,000

$ 937,000

$ 259,000

$ 675,000

$ 74,000

$ 315,184,000

$ 1,945,000

$ 8,053,000

Merck KGaA

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Right to license, number of development programs | development_program

4

Right to license, number of clinical stage programs | clinical-stage_program

2

Number of pre-clinical stage programs | pre-clinical_stage_program

2

Up-front payment

230,000,000

230,000,000

Proceeds from collaborators

193,600,000

Collaborative revenues, related to upfront payment upon delivery of license and to research and development transition activities

246,600,000

Collaborative revenues

$ 16,600,000

Time period of notice required to terminate

90 days

Time period of notice required to terminate after product has received marketing approval

180 days

German tax authority | Merck KGaA

Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]

Collaborative revenues, tax withholding

$ 36,400,000

Collaborative Arrangements - Pa

Collaborative Arrangements - Parion Sciences, Inc. (Details) - USD ($)	1 Months Ended	3 Months Ended								12 Months Ended
	Jun. 30, 2015	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative revenues		$ 29,061,000	$ 26,292,000	$ 27,286,000	$ 232,545,000	$ 937,000	$ 259,000	$ 675,000	$ 74,000	$ 315,184,000	$ 1,945,000	$ 8,053,000
(Benefit from) provision for income taxes		10,257,000	(125,903,000)	4,337,000	3,985,000	$ (7,453,000)	$ 503,000	$ 18,130,000	$ 5,485,000	(107,324,000)	16,665,000	30,381,000
Intangible asset impairment charge		$ 0	255,340,000	0	$ 0					255,340,000	0	0
Parion Sciences, Inc
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Up-front payment	$ 80,000,000									85,000,000		80,000,000
Milestone payments											5,000,000
Prior to marketing approval, time period of notice required to terminate (in days)	90 days
Subsequent to marketing approval, time period of notice required to terminate (in days)	180 days
Change of control prior to clinical trial, time period of notice required to terminate (in days)	30 days
Term of agreement following first commercial sale (in years)	10 years
Business combination, consideration VIE	$ 255,300,000
Business combination, acquisition of less than 100 percent, noncontrolling interest, fair value	164,300,000
Business combination, recognized identifiable assets acquired and liabilities assumed, deferred tax liabilities	91,000,000
Other liabilities / assets, net	10,500,000
Collaborative revenues			20,000,000	$ 20,000,000
(Benefit from) provision for income taxes			(126,200,000)
Intangible asset impairment charge			255,300,000
Business combination, contingent consideration arrangements, change in amount of contingent consideration, liability			(69,600,000)
Income tax expense (benefit), attributable to intangible asset impairment			(97,700,000)
Income tax expense (benefit), attributable to decrease in the fair value of contingent consideration liability			$ (28,500,000)
Deconsolidation, gain (loss), amount										(7,100,000)
Parion Sciences, Inc | Enac Inhibitors in Cf
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative arrangement development and regulatory potential milestone payments maximum	485,000,000
Collaborative arrangement regulatory potential milestone payments maximum	360,000,000
Parion Sciences, Inc | Enac Inhibitors in Non Cf
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative arrangement development and regulatory potential milestone payments maximum	370,000,000
Parion Sciences, Inc | Additional Enac Inhibitors
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative arrangement development and regulatory potential milestone payments maximum	$ 230,000,000
Variable Interest Entity, Primary Beneficiary
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
(Benefit from) provision for income taxes										(114,090,000)	16,743,000	29,731,000
Business combination, contingent consideration arrangements, change in amount of contingent consideration, liability										(62,560,000)	54,850,000	4,530,000
Variable Interest Entity, Primary Beneficiary | Parion Sciences, Inc
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative revenues										40,000,000
(Benefit from) provision for income taxes										14,800,000
Business combination, contingent consideration arrangements, change in amount of contingent consideration, liability										$ (63,460,000)	$ 64,800,000	$ 3,660,000

Collaborative Arrangements - Bi

Collaborative Arrangements - BioAxone Biosciences, Inc. (Details) - BioAxone Biosciences, Inc - USD ($)	Mar. 15, 2018	Oct. 31, 2014	Dec. 31, 2014
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Up-front payment			$ 10,000,000
Maximum license fees and milestone payments		$ 90,000,000
Variable interest entity, consolidated, carrying amount, in-process research and development intangible asset		29,000,000
Variable interest entity, consolidated, carrying amount, deferred tax liability		$ 11,300,000
Subsequent Event
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative arrangements, purchase option, term of extension of expiration date	1 year

Collaborative Arrangements - Ag

Collaborative Arrangements - Aggregate VIE Financial Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Variable Interest Entity, Primary Beneficiary, Does Not Hold Majority Voting Interest, Disclosures [Abstract]
(Benefit from) provision for income taxes	$ 10,257	$ (125,903)	$ 4,337	$ 3,985	$ (7,453)	$ 503	$ 18,130	$ 5,485	$ (107,324)	$ 16,665	$ 30,381
Net loss (income) attributable to noncontrolling interest	(1,501)	188,315	$ (13,173)	$ (1,792)	5,186	$ 696	$ (28,374)	$ (5,529)	171,849	(28,021)	31,847
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net:
Restricted cash and cash equivalents (VIE)	1,489				47,762				1,489	47,762
Prepaid expenses and other current assets	165,635				71,253				165,635	71,253
Intangible assets	29,000				284,340				29,000	284,340
Other assets	7,783				11,885				7,783	11,885
Accounts payable	73,994				61,451				73,994	61,451
Other current liabilities	443,961				315,249				443,961	315,249
Deferred tax liability	6,341				134,063				6,341	134,063
Other liabilities	26,048				28,699				26,048	28,699
Noncontrolling interest	13,727				181,609				13,727	181,609
Parion Sciences, Inc
Variable Interest Entity, Primary Beneficiary, Does Not Hold Majority Voting Interest, Disclosures [Abstract]
(Benefit from) provision for income taxes		(126,200)
Decrease (increase) in fair value of contingent payments		$ 69,600
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity, Primary Beneficiary, Does Not Hold Majority Voting Interest, Disclosures [Abstract]
Loss attributable to noncontrolling interest before (benefit from) provision for income taxes and changes in fair value of contingent payments									223,379	10,086	6,646
(Benefit from) provision for income taxes									(114,090)	16,743	29,731
Decrease (increase) in fair value of contingent payments									62,560	(54,850)	(4,530)
Net loss (income) attributable to noncontrolling interest									171,849	(28,021)	31,847
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net:
Restricted cash and cash equivalents (VIE)	1,489				47,762				1,489	47,762
Prepaid expenses and other current assets	22				6,812				22	6,812
Intangible assets	29,000				284,340				29,000	284,340
Other assets	256				399				256	399
Accounts payable	1,021				415				1,021	415
Taxes payable	2,171				1,330				2,171	1,330
Other current liabilities	0				2,137				0	2,137
Deferred tax liability	4,756				131,446				4,756	131,446
Other liabilities	0				300				0	300
Noncontrolling interest	13,727				181,609				13,727	181,609
Variable Interest Entity, Primary Beneficiary | Parion Sciences, Inc
Variable Interest Entity, Primary Beneficiary, Does Not Hold Majority Voting Interest, Disclosures [Abstract]
(Benefit from) provision for income taxes									14,800
Decrease (increase) in fair value of contingent payments									63,460	(64,800)	(3,660)
Contingent consideration liability	0				238,800				0	238,800
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net:
Intangible assets											255,300
Variable Interest Entity, Primary Beneficiary | BioAxone Biosciences, Inc
Variable Interest Entity, Primary Beneficiary, Does Not Hold Majority Voting Interest, Disclosures [Abstract]
Decrease (increase) in fair value of contingent payments									(900)	9,950	$ (870)
Contingent consideration liability	$ 18,900				$ 18,000				$ 18,900	$ 18,000
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net:
Intangible assets												$ 29,000

Collaborative Arrangements - Mo

Collaborative Arrangements - Moderna Therapeutics, Inc. (Details) - Moderna Therapeutics, Inc. - USD ($)	1 Months Ended		3 Months Ended
	Aug. 31, 2016	Jul. 31, 2016	Sep. 30, 2016
Schedule of Collaborative Arrangement Agreements [Line Items]
Collaborative arrangement, up-front payment		$ 20,000,000	$ 20,000,000
Collaborative arrangement, investment in collaborative partner, pursuant to convertible loan agreement	$ 20,000,000
Collaborative arrangement development and regulatory potential milestone payments maximum		275,000,000
Collaborative arrangement approval and reimbursement milestones		$ 220,000,000

Collaborative Arrangements - Ja

Collaborative Arrangements - Janssen Pharmaceuticals, Inc. (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative revenues	$ 29,061	$ 26,292	$ 27,286	$ 232,545	$ 937	$ 259	$ 675	$ 74	$ 315,184	$ 1,945	$ 8,053
Janssen
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative arrangement, up-front payment												$ 35,000
Collaborative revenues	$ 25,000
Reimbursement for research and development activities									$ 2,000	$ 14,700	$ 22,800
Time period of notice required to terminate									6 months

Collaborative Arrangements - Co

Collaborative Arrangements - Concert Pharmaceuticals (Details) - Concert Pharmaceuticals - USD ($) $ in Millions	1 Months Ended		3 Months Ended	12 Months Ended
	Jul. 31, 2017	Jul. 30, 2017	Sep. 30, 2017	Dec. 31, 2017
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative arrangement, development and commercialization rights potential maximum milestone payments		$ 160	$ 160
Collaborative arrangement, additional maximum milestone payments based on regulatory approval		$ 90
Collaborative funding				$ 160
Collaborative arrangement, purchase price	$ 165.1
Collaborative arrangement, transaction costs	$ 5.1

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Basic net income (loss) attributable to Vertex per common share calculation:
Net income (loss) attributable to Vertex common shareholders	$ 100,684	$ (102,952)	$ 17,996	$ 247,756	$ 32,945	$ (38,841)	$ (64,525)	$ (41,631)	$ 263,484	$ (112,052)	$ (556,334)
Less: Undistributed earnings allocated to participating securities									(293)	0	0
Net income (loss) attributable to Vertex common shareholders—basic									$ 263,191	$ (112,052)	$ (556,334)
Basic weighted-average common shares outstanding	251,557	250,268	247,521	246,024	245,454	244,920	244,482	243,831	248,858	244,685	241,312
Basic net income (loss) attributable to Vertex per common share (usd per share)	$ 0.40	$ (0.41)	$ 0.07	$ 1.01	$ 0.13	$ (0.16)	$ (0.26)	$ (0.17)	$ 1.06	$ (0.46)	$ (2.31)
Diluted net income (loss) attributable to Vertex per common share calculation:
Net income (loss) attributable to Vertex common shareholders—diluted									$ 263,196	$ (112,052)	$ (556,334)
Less: Undistributed earnings allocated to participating securities									$ (288)	$ 0	$ 0
Employee stock purchase plan (in shares)									28	0	0
Weighted-average shares used to compute diluted net income (loss) per common share	256,804	250,268	251,635	248,700	247,757	244,920	244,482	243,831	253,225	244,685	241,312
Diluted net income (loss) attributable to Vertex per common share (usd per share)	$ 0.39	$ (0.41)	$ 0.07	$ 0.99	$ 0.13	$ (0.16)	$ (0.26)	$ (0.17)	$ 1.04	$ (0.46)	$ (2.31)
Stock options
Diluted net income (loss) attributable to Vertex per common share calculation:
Share-based payment arrangements (in shares)									2,797	0	0
Antidilutive securities excluded from computation of earnings per share (in shares)									3,554	12,642	11,145
Unvested restricted stock and restricted stock units (including PSUs)
Diluted net income (loss) attributable to Vertex per common share calculation:
Antidilutive securities excluded from computation of earnings per share (in shares)									411	3,546	3,024
Restricted stock and restricted stock units (including PSUs)
Diluted net income (loss) attributable to Vertex per common share calculation:
Share-based payment arrangements (in shares)									1,542	0	0

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Level 1 | Variable Interest Entity, Primary Beneficiary | BioAxone Biosciences, Inc
Financial instruments carried at fair value (asset position):
Cash and cash equivalents	$ 1,500
Recurring basis
Financial instruments carried at fair value (asset position):
Total financial assets	1,108,253	$ 546,765
Total financial liabilities	(14,508)	(144)
Recurring basis | Money market funds
Financial instruments carried at fair value (asset position):
Cash equivalents:	614,951	280,560
Recurring basis | Government-sponsored enterprise securities
Financial instruments carried at fair value (asset position):
Cash equivalents:	12,678
Marketable securities:	2,303	15,508
Recurring basis | Commercial paper
Financial instruments carried at fair value (asset position):
Cash equivalents:	57,357
Marketable securities:	80,263	59,404
Recurring basis | Corporate equity securities
Financial instruments carried at fair value (asset position):
Marketable securities:	74,821	64,560
Recurring basis | Corporate debt securities
Financial instruments carried at fair value (asset position):
Marketable securities:	265,867	111,140
Recurring basis | Prepaid and other current assets | Foreign currency forward contracts
Financial instruments carried at fair value (asset position):
Prepaid and other current assets:	13	14,407
Recurring basis | Other assets | Foreign currency forward contracts
Financial instruments carried at fair value (asset position):
Other assets:		1,186
Recurring basis | Other liabilities, current portion | Foreign currency forward contracts
Financial instruments carried at fair value (asset position):
Other liabilities, current portion:	(13,642)	(144)
Recurring basis | Other liabilities, excluding current portion | Foreign currency forward contracts
Financial instruments carried at fair value (asset position):
Other liabilities, excluding current portion:	(866)
Recurring basis | Level 1
Financial instruments carried at fair value (asset position):
Total financial assets	704,753	360,628
Total financial liabilities	0	0
Recurring basis | Level 1 | Money market funds
Financial instruments carried at fair value (asset position):
Cash equivalents:	614,951	280,560
Recurring basis | Level 1 | Government-sponsored enterprise securities
Financial instruments carried at fair value (asset position):
Cash equivalents:	12,678
Marketable securities:	2,303	15,508
Recurring basis | Level 1 | Commercial paper
Financial instruments carried at fair value (asset position):
Cash equivalents:	0
Marketable securities:	0	0
Recurring basis | Level 1 | Corporate equity securities
Financial instruments carried at fair value (asset position):
Marketable securities:	74,821	64,560
Recurring basis | Level 1 | Corporate debt securities
Financial instruments carried at fair value (asset position):
Marketable securities:	0	0
Recurring basis | Level 1 | Prepaid and other current assets | Foreign currency forward contracts
Financial instruments carried at fair value (asset position):
Prepaid and other current assets:	0	0
Recurring basis | Level 1 | Other assets | Foreign currency forward contracts
Financial instruments carried at fair value (asset position):
Other assets:		0
Recurring basis | Level 1 | Other liabilities, current portion | Foreign currency forward contracts
Financial instruments carried at fair value (asset position):
Other liabilities, current portion:	0	0
Recurring basis | Level 1 | Other liabilities, excluding current portion | Foreign currency forward contracts
Financial instruments carried at fair value (asset position):
Other liabilities, excluding current portion:	0
Recurring basis | Level 2
Financial instruments carried at fair value (asset position):
Total financial assets	403,500	186,137
Total financial liabilities	(14,508)	(144)
Recurring basis | Level 2 | Money market funds
Financial instruments carried at fair value (asset position):
Cash equivalents:	0	0
Recurring basis | Level 2 | Government-sponsored enterprise securities
Financial instruments carried at fair value (asset position):
Cash equivalents:	0
Marketable securities:	0	0
Recurring basis | Level 2 | Commercial paper
Financial instruments carried at fair value (asset position):
Cash equivalents:	57,357
Marketable securities:	80,263	59,404
Recurring basis | Level 2 | Corporate equity securities
Financial instruments carried at fair value (asset position):
Marketable securities:	0	0
Recurring basis | Level 2 | Corporate debt securities
Financial instruments carried at fair value (asset position):
Marketable securities:	265,867	111,140
Recurring basis | Level 2 | Prepaid and other current assets | Foreign currency forward contracts
Financial instruments carried at fair value (asset position):
Prepaid and other current assets:	13	14,407
Recurring basis | Level 2 | Other assets | Foreign currency forward contracts
Financial instruments carried at fair value (asset position):
Other assets:		1,186
Recurring basis | Level 2 | Other liabilities, current portion | Foreign currency forward contracts
Financial instruments carried at fair value (asset position):
Other liabilities, current portion:	(13,642)	(144)
Recurring basis | Level 2 | Other liabilities, excluding current portion | Foreign currency forward contracts
Financial instruments carried at fair value (asset position):
Other liabilities, excluding current portion:	(866)
Recurring basis | Level 3
Financial instruments carried at fair value (asset position):
Total financial assets	0	0
Total financial liabilities	0	0
Recurring basis | Level 3 | Money market funds
Financial instruments carried at fair value (asset position):
Cash equivalents:	0	0
Recurring basis | Level 3 | Government-sponsored enterprise securities
Financial instruments carried at fair value (asset position):
Cash equivalents:	0
Marketable securities:	0	0
Recurring basis | Level 3 | Commercial paper
Financial instruments carried at fair value (asset position):
Cash equivalents:	0
Marketable securities:	0	0
Recurring basis | Level 3 | Corporate equity securities
Financial instruments carried at fair value (asset position):
Marketable securities:	0	0
Recurring basis | Level 3 | Corporate debt securities
Financial instruments carried at fair value (asset position):
Marketable securities:	0	0
Recurring basis | Level 3 | Prepaid and other current assets | Foreign currency forward contracts
Financial instruments carried at fair value (asset position):
Prepaid and other current assets:	0	0
Recurring basis | Level 3 | Other assets | Foreign currency forward contracts
Financial instruments carried at fair value (asset position):
Other assets:		0
Recurring basis | Level 3 | Other liabilities, current portion | Foreign currency forward contracts
Financial instruments carried at fair value (asset position):
Other liabilities, current portion:	0	$ 0
Recurring basis | Level 3 | Other liabilities, excluding current portion | Foreign currency forward contracts
Financial instruments carried at fair value (asset position):
Other liabilities, excluding current portion:	$ 0

Marketable Securities (Details)

Marketable Securities (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Summary of cash, cash equivalents and marketable securities
Amortized Cost	$ 2,057,652,000	$ 1,413,220,000
Gross Unrealized Gains	31,608,000	21,422,000
Gross Unrealized Losses	(594,000)	(85,000)
Fair Value	2,088,666,000	1,434,557,000
Other than temporary impairment losses	0	0	$ 0
Realized gains or losses	0	0	$ 0
Cash and money market funds
Summary of cash, cash equivalents and marketable securities
Amortized Cost	1,595,377,000	1,183,945,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	1,595,377,000	1,183,945,000
Government-sponsored enterprise securities
Summary of cash, cash equivalents and marketable securities
Amortized Cost	12,679,000
Gross Unrealized Gains	0
Gross Unrealized Losses	(1,000)
Fair Value	12,678,000
Commercial paper
Summary of cash, cash equivalents and marketable securities
Amortized Cost	57,371,000
Gross Unrealized Gains	0
Gross Unrealized Losses	(14,000)
Fair Value	57,357,000
Total cash and cash equivalents
Summary of cash, cash equivalents and marketable securities
Amortized Cost	1,665,427,000	1,183,945,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(15,000)	0
Fair Value	1,665,412,000	1,183,945,000
Corporate equity securities
Summary of cash, cash equivalents and marketable securities
Amortized Cost	43,213,000	43,213,000
Gross Unrealized Gains	31,608,000	21,347,000
Gross Unrealized Losses	0	0
Fair Value	74,821,000	64,560,000
Government-sponsored enterprise securities
Summary of cash, cash equivalents and marketable securities
Amortized Cost	2,304,000	15,506,000
Gross Unrealized Gains	0	2,000
Gross Unrealized Losses	(1,000)	0
Fair Value	2,303,000	15,508,000
Corporate debt securities (matures within 1 year)
Summary of cash, cash equivalents and marketable securities
Amortized Cost	215,639,000	111,225,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(363,000)	(85,000)
Fair Value	215,276,000	111,140,000
Corporate debt securities (matures after 1 year through 5 years)
Summary of cash, cash equivalents and marketable securities
Amortized Cost	50,697,000
Gross Unrealized Gains	0
Gross Unrealized Losses	(106,000)
Fair Value	50,591,000
Commercial paper (matures within 1 year)
Summary of cash, cash equivalents and marketable securities
Amortized Cost	80,372,000	59,331,000
Gross Unrealized Gains	0	73,000
Gross Unrealized Losses	(109,000)	0
Fair Value	80,263,000	59,404,000
Total marketable securities
Summary of cash, cash equivalents and marketable securities
Amortized Cost	392,225,000	229,275,000
Gross Unrealized Gains	31,608,000	21,422,000
Gross Unrealized Losses	(579,000)	(85,000)
Fair Value	$ 423,254,000	$ 250,612,000

Accumulated Other Comprehensi68

Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	$ 1,338,191	$ 1,093,628	$ 1,096,183
Other comprehensive (loss) income before reclassifications	(35,390)	28,996	5,633
Amounts reclassified from accumulated other comprehensive income (loss)	2,645	(9,647)	(4,726)
Total changes in other comprehensive (loss) income	(32,745)	19,349	907
Balance	2,042,306	1,338,191	1,093,628
Foreign currency translation adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	(7,862)	(2,080)	(971)
Other comprehensive (loss) income before reclassifications	(13,169)	(5,782)	(1,109)
Amounts reclassified from accumulated other comprehensive income (loss)	0	0	0
Total changes in other comprehensive (loss) income	(13,169)	(5,782)	(1,109)
Balance	(21,031)	(7,862)	(2,080)
Unrealized holding gains (losses) on marketable securities, net of tax
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	17,521	126	(123)
Other comprehensive (loss) income before reclassifications	6,954	17,395	249
Amounts reclassified from accumulated other comprehensive income (loss)	0	0	0
Total changes in other comprehensive (loss) income	6,954	17,395	249
Balance	24,475	17,521	126
Unrealized (losses) gains on foreign currency forward contracts, net of tax
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	11,514	3,778	2,011
Other comprehensive (loss) income before reclassifications	(29,175)	17,383	6,493
Amounts reclassified from accumulated other comprehensive income (loss)	2,645	(9,647)	(4,726)
Total changes in other comprehensive (loss) income	(26,530)	7,736	1,767
Balance	(15,016)	11,514	3,778
AOCI Attributable to Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	21,173	1,824	917
Total changes in other comprehensive (loss) income	(32,745)	19,349	907
Balance	$ (11,572)	$ 21,173	$ 1,824

Hedging - Notional Amount (Deta

Hedging - Notional Amount (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Derivative term	1 month
Designated as Hedging Instrument | Cash Flow Hedging | Foreign currency forward contracts
Derivative [Line Items]
Notional amount of foreign currency forward contract	$ 365,212	$ 253,381
Designated as Hedging Instrument | Cash Flow Hedging | Foreign currency forward contracts | Euro
Derivative [Line Items]
Notional amount of foreign currency forward contract	257,230	164,368
Designated as Hedging Instrument | Cash Flow Hedging | Foreign currency forward contracts | British pound sterling
Derivative [Line Items]
Notional amount of foreign currency forward contract	77,481	65,237
Designated as Hedging Instrument | Cash Flow Hedging | Foreign currency forward contracts | Australian dollar
Derivative [Line Items]
Notional amount of foreign currency forward contract	$ 30,501	$ 23,776
Minimum | Cash Flow Hedging | Foreign currency forward contracts
Derivative [Line Items]
Derivative term	1 month
Maximum | Cash Flow Hedging | Foreign currency forward contracts
Derivative [Line Items]
Derivative term	18 months

Hedging - Derivative Fair Value

Hedging - Derivative Fair Value (Details) - Foreign currency forward contracts - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Foreign Currency Cash Flow Hedge Derivative at Fair Value [Abstract]
Total assets	$ 13	$ 15,593
Total liabilities	(14,508)	(144)
Designated as Hedging Instrument
Foreign Currency Cash Flow Hedge Derivative at Fair Value [Abstract]
Total assets	13	15,593
Total liabilities	(14,508)	(144)
Prepaid and other current assets | Designated as Hedging Instrument
Foreign Currency Cash Flow Hedge Derivative at Fair Value [Abstract]
Fair value - assets	13	14,407
Prepaid and other current assets | Not designated as hedging instrument
Foreign Currency Cash Flow Hedge Derivative at Fair Value [Abstract]
Fair value - assets	0
Total assets		660
Other liabilities, current portion | Designated as Hedging Instrument
Foreign Currency Cash Flow Hedge Derivative at Fair Value [Abstract]
Fair value - liabilities	(13,642)	(144)
Other liabilities, current portion | Not designated as hedging instrument
Foreign Currency Cash Flow Hedge Derivative at Fair Value [Abstract]
Total liabilities	(684)	0
Other assets | Designated as Hedging Instrument
Foreign Currency Cash Flow Hedge Derivative at Fair Value [Abstract]
Fair value - assets	0	1,186
Other liabilities, excluding current portion | Designated as Hedging Instrument
Foreign Currency Cash Flow Hedge Derivative at Fair Value [Abstract]
Fair value - liabilities	$ (866)	$ 0

Hedging - Offsetting Derivative

Hedging - Offsetting Derivatives (Details) - Foreign currency forward contracts - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Offsetting Derivative Assets [Abstract]
Gross Amounts Recognized	$ 13	$ 15,593
Gross Amounts Offset	0	0
Gross Amount Presented	13	15,593
Gross Amount Not Offset	(13)	(144)
Legal Offset	0	15,449
Offsetting Derivative Liabilities [Abstract]
Gross Amounts Recognized	(14,508)	(144)
Gross Amounts Offset	0	0
Gross Amount Presented	(14,508)	(144)
Gross Amount Not Offset	13	144
Legal Offset	$ (14,495)	$ 0

Hedging - Narrative (Details)

Hedging - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative term	1 month
Foreign currency forward contracts | Not designated as hedging instrument
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of foreign currency forward contract	$ 122.8
Derivative term	1 month
Other nonoperating income (expense) | Foreign currency forward contracts | Not designated as hedging instrument
Derivative Instruments and Hedging Activities Disclosures [Line Items]
(Loss) gain recognized on forward contracts not designated as hedges	$ (14.1)	$ 6.9

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Inventory Disclosure [Abstract]
Raw materials	$ 20,924	$ 6,348
Work-in-process	74,237	56,672
Finished goods	16,669	14,584
Total	$ 111,830	$ 77,604

Property and Equipment (Details

Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	$ 1,221,560	$ 1,086,160
Less: accumulated depreciation	(432,123)	(387,798)
Total property and equipment, net	789,437	698,362
Buildings
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	634,061	548,232
Furniture and equipment
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	256,509	236,634
Software
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	151,890	134,321
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	117,806	108,702
Computers
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	$ 61,294	$ 58,271

Property and Equipment - Narrat

Property and Equipment - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Total capital leased assets, gross	$ 100,900	$ 101,300
Capital leases accumulated depreciation	43,400	37,900
Total capitalized internally developed software, gross	789,437	698,362
Capitalized internally developed software accumulated depreciation	432,123	387,798
Depreciation expense	61,400	60,800	$ 60,000
Internal Use Software
Property, Plant and Equipment [Line Items]
Total capitalized internally developed software, gross	21,100	17,800
Capitalized internally developed software accumulated depreciation	$ 13,000	$ 9,200

Intangible Assets and Goodwill

Intangible Assets and Goodwill (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Indefinite-Lived Intangible Assets [Line Items]
Intangible assets	$ 29,000,000				$ 284,340,000				$ 29,000,000	$ 284,340,000
Intangible asset impairment charge	0	$ 255,340,000	$ 0	$ 0					255,340,000	0	$ 0
(Benefit from) provision for income taxes	10,257,000	(125,903,000)	$ 4,337,000	$ 3,985,000	(7,453,000)	$ 503,000	$ 18,130,000	$ 5,485,000	(107,324,000)	16,665,000	30,381,000
Goodwill	50,384,000				50,384,000				50,384,000	50,384,000
Parion Sciences, Inc
Indefinite-Lived Intangible Assets [Line Items]
Intangible asset impairment charge		255,300,000
(Benefit from) provision for income taxes		(126,200,000)
Variable Interest Entity, Primary Beneficiary
Indefinite-Lived Intangible Assets [Line Items]
Intangible assets	$ 29,000,000				$ 284,340,000				29,000,000	284,340,000
(Benefit from) provision for income taxes									(114,090,000)	$ 16,743,000	29,731,000
Variable Interest Entity, Primary Beneficiary | Parion Sciences, Inc
Indefinite-Lived Intangible Assets [Line Items]
Intangible assets											$ 255,300,000
Fair value of intangible asset		0
(Benefit from) provision for income taxes									14,800,000
Variable Interest Entity, Primary Beneficiary | BioAxone Biosciences, Inc
Indefinite-Lived Intangible Assets [Line Items]
Intangible assets												$ 29,000,000
Other Intangible Assets | Variable Interest Entity, Primary Beneficiary | Parion Sciences, Inc
Indefinite-Lived Intangible Assets [Line Items]
Intangible asset impairment charge		$ 255,300,000							255,300,000
(Benefit from) provision for income taxes									$ (97,700,000)

Additional Balance Sheet Deta77

Additional Balance Sheet Detail (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Prepaid and other current assets
Prepaid expenses	$ 62,475	$ 36,134
Collaborative accounts receivable	28,907	719
Other receivables and assets	74,253	34,400
Total	165,635	71,253
Accrued expenses
Payroll and benefits	113,026	86,387
Research, development and commercial contract costs	98,411	62,756
Product revenue allowances	119,919	86,533
Royalty payable	73,044	52,845
Other	39,561	26,728
Total	$ 443,961	$ 315,249

Long Term Obligations - Fan Pie

Long Term Obligations - Fan Pier Leases (Details) $ in Thousands, ft² in Millions	12 Months Ended
	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2011ft²leasebuilding
Lessee, Lease, Description [Line Items]
Depreciation expense	$ 61,400	$ 60,800	$ 60,000
Rental expense	19,200	19,100	18,100
Property and equipment, net	789,437	698,362
Fan Pier Leases
Lessee, Lease, Description [Line Items]
Number of leases | lease				2
Area of real estate property (in square feet) | ft²				1.1
Lease agreements number of buildings | building				2
Optional term of lease agreement (in years)				10 years
Buildings | Fan Pier Leases
Lessee, Lease, Description [Line Items]
Interest expense	60,100	60,200	60,200
Depreciation expense	13,300	13,300	13,300
Rental expense	6,500	6,500	$ 6,500
Construction financing lease obligation, current and noncurrent	472,100	472,600
Construction in Progress | Fan Pier Leases
Lessee, Lease, Description [Line Items]
Property and equipment, net	$ 475,700	$ 489,000

Long Term Obligations - San Die

Long Term Obligations - San Diego Lease (Details) ft² in Thousands, $ in Thousands	Dec. 02, 2015USD ($)ft²term	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Property, Plant and Equipment [Line Items]
Property and equipment, net		$ 789,437	$ 698,362
San Diego Leases
Property, Plant and Equipment [Line Items]
Area of real estate property (in square feet) | ft²	170
Length of lease	16 years
Average yearly aggregate rent	$ 10,200
Amount of optional renewal terms | term	2
Optional renewal term length	5 years
Construction financing lease obligation, current and noncurrent		87,400	12,600
Construction in Progress | San Diego Leases
Property, Plant and Equipment [Line Items]
Property and equipment, net		$ 94,600	$ 15,000

Long Term Obligations - Revolvi

Long Term Obligations - Revolving Credit Facility (Details)	1 Months Ended
	Feb. 28, 2017USD ($)	Oct. 31, 2016USD ($)
Line of Credit Facility [Line Items]
Line of of credit facility, fair value of amount outstanding	$ 300,000,000
Line of credit facility, additional borrowing capacity		$ 300,000,000
Line of Credit
Line of Credit Facility [Line Items]
Line of credit facility, current borrowing capacity		$ 500,000,000
Debt covenant, consolidated leverage ratio		3
Debt covenant, minimum consolidated EBITDA		$ 200,000,000
Line of Credit | Minimum | Base Rate
Line of Credit Facility [Line Items]
Interest rate (percent)		0.75%
Line of Credit | Minimum | Eurodollar
Line of Credit Facility [Line Items]
Interest rate (percent)		1.75%
Line of Credit | Maximum | Base Rate
Line of Credit Facility [Line Items]
Interest rate (percent)		1.50%
Line of Credit | Maximum | Eurodollar
Line of Credit Facility [Line Items]
Interest rate (percent)		2.50%

Long Term Obligations - Term Lo

Long Term Obligations - Term Loan (Details) - Senior Secured Term Loan - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2014	Jul. 31, 2014
Debt Instrument [Line Items]
Face amount of term loan		$ 300,000,000
Gains (losses) on extinguishment of debt	$ (2,200,000)
Interest rate (percent)		6.20%	7.20%
Unamortized discount on term loan		$ 5,300,000
Minimum | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate (percent)		5.00%

Common Stock, Preferred Stock82

Common Stock, Preferred Stock and Equity Plans - Stock and Option Plans (Details)	12 Months Ended
	Dec. 31, 2017voteshares	Dec. 31, 2015shares	Dec. 31, 2016shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares authorized (shares)	500,000,000		500,000,000
Common stock, number of votes per share | vote	1
Preferred stock, shares authorized (shares)	1,000,000		1,000,000
Preferred stock, shares issued (shares)	0		0
Preferred stock, shares outstanding (shares)	0		0
Awards outstanding (shares)	13,491,491
Additional awards authorized for grant (shares)	11,427,114
2013 Stock and Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards outstanding (shares)	10,388,723
Additional awards authorized for grant (shares)	11,427,114
Additional shares authorized (shares)	6,750,000	7,800,000
2006 Stock and Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards outstanding (shares)	3,102,768
Additional awards authorized for grant (shares)	0
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period	10 years

Common Stock, Preferred Stock83

Common Stock, Preferred Stock and Equity Plans - Outstanding and Vested Stock Options (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Stock Options
Stock options outstanding at beginning of period (in shares)	12,642
Stock options granted (in shares)	2,359
Stock options exercised (in shares)	(4,561)
Stock options forfeited (in shares)	(611)
Stock options expired (in shares)	(62)
Stock options outstanding at end of period (in shares)	9,767	12,642
Stock options exercisable at end of period (in shares)	5,313
Weighted-average Exercise Price
Weighted-average exercise price outstanding at beginning of period (usd per share)	$ 81.41
Weighted average exercise price, granted (usd per share)	108.43
Weighted average exercise price, exercised (usd per share)	70.90
Weighted average exercise price, forfeited (usd per share)	99.53
Weighted average exercise price, expired (usd per share)	105.24
Weighted-average exercise price outstanding at end of period (usd per share)	91.57	$ 81.41
Weighted average exercise price exercisable at the end of the period (usd per share)	$ 80.14
Weighted-average Remaining Contractual Life
Weighted-average Remaining Contractual Life, outstanding (in years)	6 years 11 months 12 days
Weighted-average Remaining Contractual Life, exercisable (in years)	5 years 9 months
Aggregate Intrinsic Value
Aggregate intrinsic value, outstanding	$ 585,293
Aggregate intrinsic value, exercisable	375,472
Total intrinsic value of stock options exercised	302,800	$ 48,600	$ 252,900
Total cash received from employees as a result of employee stock option exercises	$ 323,300	$ 48,500	$ 165,600
Weighted Average
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Market share price (usd per share)	$ 150.71

Common Stock, Preferred Stock84

Common Stock, Preferred Stock and Equity Plans - Stock Options Outstanding and Exercisable (Details) shares in Thousands	12 Months Ended
	Dec. 31, 2017$ / sharesshares
Stock options outstanding and exercisable
Options outstanding (in shares) | shares	9,767
Options outstanding, weighted-average remaining contractual life	6 years 11 months 12 days
Options outstanding, weighted-average exercise price (usd per share)	$ 91.57
Options exercisable (in shares) | shares	5,313
Options exercisable, weighted-average exercise price (usd per share)	$ 80.14
$18.93–$20.00
Stock options outstanding and exercisable
Exercise price, low end of range (usd per share)	18.93
Exercise price, high end of range (usd per share)	$ 20
Options outstanding (in shares) | shares	128
Options outstanding, weighted-average remaining contractual life	1 month 6 days
Options outstanding, weighted-average exercise price (usd per share)	$ 18.93
Options exercisable (in shares) | shares	128
Options exercisable, weighted-average exercise price (usd per share)	$ 18.93
$20.01–$40.00
Stock options outstanding and exercisable
Exercise price, low end of range (usd per share)	20.01
Exercise price, high end of range (usd per share)	$ 40
Options outstanding (in shares) | shares	810
Options outstanding, weighted-average remaining contractual life	1 year 10 months 17 days
Options outstanding, weighted-average exercise price (usd per share)	$ 34.43
Options exercisable (in shares) | shares	810
Options exercisable, weighted-average exercise price (usd per share)	$ 34.43
$40.01–$60.00
Stock options outstanding and exercisable
Exercise price, low end of range (usd per share)	40.01
Exercise price, high end of range (usd per share)	$ 60
Options outstanding (in shares) | shares	798
Options outstanding, weighted-average remaining contractual life	4 years 5 months 27 days
Options outstanding, weighted-average exercise price (usd per share)	$ 49.15
Options exercisable (in shares) | shares	798
Options exercisable, weighted-average exercise price (usd per share)	$ 49.15
$60.01–$80.00
Stock options outstanding and exercisable
Exercise price, low end of range (usd per share)	60.01
Exercise price, high end of range (usd per share)	$ 80
Options outstanding (in shares) | shares	746
Options outstanding, weighted-average remaining contractual life	6 years 2 months 9 days
Options outstanding, weighted-average exercise price (usd per share)	$ 75.49
Options exercisable (in shares) | shares	653
Options exercisable, weighted-average exercise price (usd per share)	$ 75.40
$80.01–$100.00
Stock options outstanding and exercisable
Exercise price, low end of range (usd per share)	80.01
Exercise price, high end of range (usd per share)	$ 100
Options outstanding (in shares) | shares	4,350
Options outstanding, weighted-average remaining contractual life	8 years 26 days
Options outstanding, weighted-average exercise price (usd per share)	$ 89.31
Options exercisable (in shares) | shares	1,514
Options exercisable, weighted-average exercise price (usd per share)	$ 89.51
$100.01–$120.00
Stock options outstanding and exercisable
Exercise price, low end of range (usd per share)	100.01
Exercise price, high end of range (usd per share)	$ 120
Options outstanding (in shares) | shares	1,087
Options outstanding, weighted-average remaining contractual life	7 years 1 month 10 days
Options outstanding, weighted-average exercise price (usd per share)	$ 109.34
Options exercisable (in shares) | shares	633
Options exercisable, weighted-average exercise price (usd per share)	$ 109.24
$120.01–$140.00
Stock options outstanding and exercisable
Exercise price, low end of range (usd per share)	120.01
Exercise price, high end of range (usd per share)	$ 140
Options outstanding (in shares) | shares	1,223
Options outstanding, weighted-average remaining contractual life	7 years 7 months 17 days
Options outstanding, weighted-average exercise price (usd per share)	$ 130.20
Options exercisable (in shares) | shares	734
Options exercisable, weighted-average exercise price (usd per share)	$ 129.89
$140.01–$160.00
Stock options outstanding and exercisable
Exercise price, low end of range (usd per share)	140.01
Exercise price, high end of range (usd per share)	$ 160
Options outstanding (in shares) | shares	0
Options outstanding, weighted-average exercise price (usd per share)	$ 0
Options exercisable (in shares) | shares	0
Options exercisable, weighted-average exercise price (usd per share)	$ 0
$160.01–$163.74
Stock options outstanding and exercisable
Exercise price, low end of range (usd per share)	160.01
Exercise price, high end of range (usd per share)	$ 163.74
Options outstanding (in shares) | shares	625
Options outstanding, weighted-average remaining contractual life	9 years 6 months 15 days
Options outstanding, weighted-average exercise price (usd per share)	$ 162.94
Options exercisable (in shares) | shares	43
Options exercisable, weighted-average exercise price (usd per share)	$ 162.94

Common Stock, Preferred Stock85

Common Stock, Preferred Stock and Equity Plans - Restricted Stock and Restricted Stock Units and PSUs (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restricted Stock
Restricted stock and Restricted Stock Units
Beginning of the period (in shares)	2,613
Granted (in shares)	0
Vested (in shares)	(1,206)
Cancelled (in shares)	(178)
End of the period (in shares)	1,229	2,613
Restricted stock and Restricted Stock Units, weighted-average grant-date fair value
Weighted-average grant-date fair value, as of the beginning of the period (usd per share)	$ 102.54
Weighted-average grant-date fair value, granted (usd per share)	0
Weighted-average grant-date fair value, vested (usd per share)	102.99
Weighted-average grant-date fair value, cancelled (usd per share)	102.45
Weighted-average grant-date fair value, as of the end of the period (usd per share)	$ 102.12	$ 102.54
Restricted stock vested in period, total fair value	$ 157	$ 74.1	$ 124
Restricted Stock Units (excluding PSUs)
Restricted stock and Restricted Stock Units
Beginning of the period (in shares)	798
Granted (in shares)	1,719
Vested (in shares)	(278)
Cancelled (in shares)	(228)
End of the period (in shares)	2,011	798
Restricted stock and Restricted Stock Units, weighted-average grant-date fair value
Weighted-average grant-date fair value, as of the beginning of the period (usd per share)	$ 92.62
Weighted-average grant-date fair value, granted (usd per share)	113.13
Weighted-average grant-date fair value, vested (usd per share)	94.72
Weighted-average grant-date fair value, cancelled (usd per share)	97.86
Weighted-average grant-date fair value, as of the end of the period (usd per share)	$ 109.27	$ 92.62
Restricted stock vested in period, total fair value	$ 33.2	$ 5.3	$ 8
Performance-based RSUs
Restricted stock and Restricted Stock Units
Beginning of the period (in shares)	135
Granted (in shares)	392
Vested (in shares)	(15)
Cancelled (in shares)	(28)
End of the period (in shares)	484	135
Restricted stock and Restricted Stock Units, weighted-average grant-date fair value
Weighted-average grant-date fair value, as of the beginning of the period (usd per share)	$ 91.05
Weighted-average grant-date fair value, granted (usd per share)	86.71
Weighted-average grant-date fair value, vested (usd per share)	91.05
Weighted-average grant-date fair value, cancelled (usd per share)	86.52
Weighted-average grant-date fair value, as of the end of the period (usd per share)	$ 87.59	$ 91.05
Restricted stock vested in period, total fair value	$ 1.3
Potential awards, percent of target shares, minimum	0.00%
Potential awards, percent of target shares, maximum	200.00%
Performance-based RSUs | Tranche one
Restricted stock and Restricted Stock Units, weighted-average grant-date fair value
Percent of awards in tranche	50.00%
Performance period	1 year
Vesting period	3 years
Performance-based RSUs | Tranche two
Restricted stock and Restricted Stock Units, weighted-average grant-date fair value
Percent of awards in tranche	50.00%
Performance period	3 years
Vesting period	3 years

Common Stock, Preferred Stock86

Common Stock, Preferred Stock and Equity Plans - Employee Stock Purchase Plan (Details) - ESPP share issuances	12 Months Ended
	Dec. 31, 2017period$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Offering period (in months)	12 months
Number of purchase periods | period	2
Duration of purchase period	6 months
Eligible employee purchase price percentage of fair value	85.00%
Number of shares authorized (shares)	616,256
Number of shares (shares)	275,000
Average price paid per share (usd per share) | $ / shares	$ 80.71

Stock-based Compensation Expe87

Stock-based Compensation Expense (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Stock-based compensation expense:
Stock-based compensation expense	$ 290,736,000	$ 237,705,000	$ 231,025,000
Less: stock-based compensation expense capitalized to inventories	(4,906,000)	(3,607,000)	(4,087,000)
Allocated stock-based compensation expense	290,736,000	$ 237,705,000	$ 231,025,000
Stock Options
Weighted-average assumptions for options and ESPP subscriptions granted
Expected annual dividends	$ 0
Employee stock purchase plan
Weighted-average assumptions for options and ESPP subscriptions granted
Expected stock price volatility (percent)	39.09%	48.22%	47.20%
Risk-free interest rate (percent)	1.24%	0.56%	0.40%
Expected term of options (in years)	9 months	9 months	8 months 20 days
Expected annual dividends	$ 0	$ 0	$ 0
Weighted average fair value (usd per share)	$ 35.90	$ 26.86	$ 37.84
Tranche one
Weighted-average assumptions for options and ESPP subscriptions granted
Vesting rights percentage	33.30%
Tranche two
Weighted-average assumptions for options and ESPP subscriptions granted
Vesting rights percentage	33.30%
Tranche three
Weighted-average assumptions for options and ESPP subscriptions granted
Vesting rights percentage	33.30%
Performance-based RSUs
Weighted-average assumptions for options and ESPP subscriptions granted
Potential awards, percent of target shares, minimum	0.00%
Potential awards, percent of target shares, maximum	200.00%
Weighted average fair value (usd per share)	$ 86.71
Performance-based RSUs | Tranche one
Weighted-average assumptions for options and ESPP subscriptions granted
Vesting period	3 years
Performance-based RSUs | Tranche two
Weighted-average assumptions for options and ESPP subscriptions granted
Vesting period	3 years
Financial performance shares
Weighted-average assumptions for options and ESPP subscriptions granted
Vesting period	3 years
Non-financial performance shares
Weighted-average assumptions for options and ESPP subscriptions granted
Vesting period	3 years
Stock options
Stock-based compensation expense:
Stock-based compensation expense	$ 105,367,000	$ 114,768,000	$ 129,276,000
Type of award:
Unrecognized Expense	$ 147,402,000
Weighted-average Recognition Period	2 years 5 months 12 days
Weighted-average grant-date fair value, granted (usd per share)	$ 43.27	$ 37.93	$ 52.16
Weighted-average assumptions for options and ESPP subscriptions granted
Expected stock price volatility (percent)	45.31%	46.77%	47.29%
Risk-free interest rate (percent)	1.94%	1.32%	1.61%
Expected term of options (in years)	4 years 8 months 5 days	4 years 10 months 28 days	5 years 3 months 11 days
Expected annual dividends	$ 0	$ 0	$ 0
Restricted stock and restricted stock units (including PSUs)
Stock-based compensation expense:
Stock-based compensation expense	181,258,000	118,709,000	98,811,000
Type of award:
Unrecognized Expense	$ 254,302,000
Weighted-average Recognition Period	2 years 5 months 19 days
ESPP share issuances
Stock-based compensation expense:
Stock-based compensation expense	$ 9,017,000	7,835,000	7,025,000
Type of award:
Unrecognized Expense	$ 4,245,000
Weighted-average Recognition Period	7 months 2 days
Research and development expenses
Stock-based compensation expense:
Stock-based compensation expense	$ 181,900,000	153,451,000	152,955,000
Sales, general and administrative expenses
Stock-based compensation expense:
Stock-based compensation expense	$ 108,836,000	$ 84,254,000	$ 78,070,000

Other Arrangements (Details)

Other Arrangements (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2008	Dec. 31, 2017
Sale of HIV Protease Inhibitor Royalty Stream
Gross proceeds from sale of royalty rights receivable from GlaxoSmithKline	$ 160
Royalty purchase agreement deferred revenue		$ 6.9

Income Taxes - Components of In

Income Taxes - Components of Income and Provision for (Benefit from) Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Components of income (loss) before provision for (benefit from) income taxes
United States									$ 330,340	$ (147,860)	$ (272,326)
Foreign									(346,029)	80,494	(285,474)
Loss before (benefit from) provision for income taxes	$ 112,442	$ (417,170)	$ 35,506	$ 253,533	$ 20,306	$ (39,034)	$ (18,021)	$ (30,617)	(15,689)	(67,366)	(557,800)
Current taxes:
United States									11,559	(3,821)	25,623
Foreign									3,576	1,794	831
State									5,025	1,836	3,629
Total current taxes									20,160	(191)	30,083
Deferred taxes:
United States									(113,805)	18,659	497
Foreign									(3,222)	(3,359)	(355)
State									(10,457)	1,556	156
Total deferred taxes									(127,484)	16,856	298
(Benefit from) provision for income taxes	$ 10,257	$ (125,903)	$ 4,337	$ 3,985	$ (7,453)	$ 503	$ 18,130	$ 5,485	$ (107,324)	$ 16,665	$ 30,381

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Tax Carryforwards
Increase (decrease) in valuation allowance	$ (178,200,000)	$ 14,800,000	$ 306,400,000
Deferred tax liabilities recognized in other liabilities, excluding current portion	6,341,000	134,063,000
Valuation allowance	1,552,942,000	1,731,186,000
Unrecognized tax benefits	3,800,000	0	$ 400,000
Income tax penalties and interest accrued	0
Variable Interest Entity, Primary Beneficiary
Tax Carryforwards
Deferred tax liabilities recognized in other liabilities, excluding current portion	4,756,000	$ 131,446,000
Internal Revenue Service (IRS)
Tax Carryforwards
Operating loss carryforwards	3,600,000,000
Tax credit carryforwards	312,500,000
State and Local Jurisdiction
Tax Carryforwards
Operating loss carryforwards	880,700,000
Tax credit carryforwards	$ 115,700,000

Income Taxes - Effective Income

Income Taxes - Effective Income Tax Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of Income Tax Expense:
Loss before (benefit from) provision for income taxes	$ 112,442	$ (417,170)	$ 35,506	$ 253,533	$ 20,306	$ (39,034)	$ (18,021)	$ (30,617)	$ (15,689)	$ (67,366)	$ (557,800)
Expected benefit from income taxes									(5,491)	(23,578)	(195,230)
State taxes, net of federal benefit									4,742	3,621	3,800
Foreign income tax rate differential									77,801	21,346	47,402
Tax credits									(49,088)	(47,773)	(55,696)
Provision for (benefit from) income taxes attributable to valuation allowances									(584,917)	14,837	226,169
Permanent items									21,825	24,749	5,817
Rate change									575,192	12,836	(1,224)
Stock compensation (benefit) shortfalls and cancellations									(21,453)	4,162	951
Tax attribute expiration									0	9,947	0
Deconsolidation of VIE									(126,183)	0	0
Other									248	(3,482)	(1,608)
(Benefit from) provision for income taxes	$ 10,257	$ (125,903)	$ 4,337	$ 3,985	$ (7,453)	$ 503	$ 18,130	$ 5,485	$ (107,324)	$ 16,665	$ 30,381

Income Taxes - Deferred Tax Ass

Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Net operating loss	$ 1,004,404	$ 1,232,399
Tax credit carryforwards	440,429	367,402
Intangible assets	54,091	34,938
Deferred revenues	19,593	31,205
Stock-based compensation	83,196	110,446
Inventories	4,250	4,705
Accrued expenses	17,808	23,078
Construction financing lease obligation	109,354	177,735
Other	1,417	27
Gross deferred tax assets	1,734,542	1,981,935
Valuation allowance	(1,552,942)	(1,731,186)
Total deferred tax assets	181,600	250,749
Deferred tax liabilities:
Property and equipment	(101,019)	(169,089)
Acquired intangibles	(6,341)	(134,063)
Deferred revenue	(73,357)	(73,357)
Unrealized gain	(6,401)	(7,967)
Net deferred tax liabilities	$ (5,518)	$ (133,727)

Restructuring Expenses (Details

Restructuring Expenses (Details) $ in Thousands	1 Months Ended	3 Months Ended								12 Months Ended
	Feb. 28, 2017position	Dec. 31, 2017USD ($)	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Restructuring Reserve [Roll Forward]
Restructuring expense		$ 387	$ 337	$ 3,523	$ 9,999	$ 224	$ 8	$ 343	$ 687	$ 14,246	$ 1,262	$ 2,206
Research and development restructuring
Restructuring Cost and Reserve [Line Items]
Number of positions eliminated | position	70
Restructuring Reserve [Roll Forward]
Liability, beginning of the period					$ 0					0
Restructuring expense										12,503
Cash payments										(8,602)
Asset impairments and other non-cash items										(1,812)
Liability, end of the period		$ 2,089				$ 0				$ 2,089	$ 0

Employee Benefits (Details)

Employee Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Retirement Benefits [Abstract]
Maximum percentage of annual compensation contributed by the participant (percent)	60.00%
Company contribution	$ 12.3	$ 11.8	$ 12.8
Common stock shares remained available for grant (shares)	754,744

Commitments and Contingencies -

Commitments and Contingencies - Lease Commitments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Future minimum commitments under facility leases commitments with terms of more than one year
2,018	$ 84,451
2,019	92,915
2,020	95,672
2,021	93,879
2,022	93,258
Thereafter	649,785
Total minimum lease payments	1,109,960
Sublease income 2018	6,000
Rental expense	19,200	$ 19,100	$ 18,100
Fan Pier Leases
Future minimum commitments under facility leases commitments with terms of more than one year
2,018	61,606
2,019	72,589
2,020	72,589
2,021	72,589
2,022	72,589
Thereafter	462,442
Total minimum lease payments	814,404
San Diego Leases
Future minimum commitments under facility leases commitments with terms of more than one year
2,018	2,979
2,019	5,324
2,020	9,127
2,021	9,127
2,022	9,127
Thereafter	129,394
Total minimum lease payments	165,078
Other Leases
Future minimum commitments under facility leases commitments with terms of more than one year
2,018	19,866
2,019	15,002
2,020	13,956
2,021	12,163
2,022	11,542
Thereafter	57,949
Total minimum lease payments	$ 130,478

Commitments and Contingencies96

Commitments and Contingencies - Capital Lease Financing Obligations (Details) $ in Thousands	Dec. 31, 2017USD ($)
Capital Leases, Future Minimum Payments Due [Abstract]
2,018	$ 24,004
2,019	10,252
2,020	5,434
2,021	3,676
2,022	1,706
Thereafter	387
Total payments	45,459
Less: amount representing interest	(2,432)
Present value of payments	$ 43,027
Minimum
Capital Leased Assets
Effective interest rate (less than for minimum)	1.00%
Maximum
Capital Leased Assets
Effective interest rate (less than for minimum)	9.00%

Commitments and Contingencies97

Commitments and Contingencies - Contingencies (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Indemnification claims	$ 0
Contingent liabilities	$ 0	$ 0

Segment Information - Revenues

Segment Information - Revenues by Product (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017USD ($)	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2017USD ($)segment	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Segment Reporting [Abstract]
Number of operating segments | segment									1
Revenue from External Customer [Line Items]
Total product revenues, net	$ 621,228	$ 549,642	$ 513,988	$ 480,622	$ 453,882	$ 409,689	$ 425,651	$ 394,410	$ 2,165,480	$ 1,683,632	$ 1,000,324
ORKAMBI
Revenue from External Customer [Line Items]
Total product revenues, net									1,320,850	979,590	350,663
KALYDECO
Revenue from External Customer [Line Items]
Total product revenues, net									844,630	703,432	631,674
INCIVEK
Revenue from External Customer [Line Items]
Total product revenues, net									$ 0	$ 610	$ 17,987

Segment Information - Revenue b

Segment Information - Revenue by Geographic Location (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 651,634	$ 578,165	$ 544,135	$ 714,718	$ 458,706	$ 413,783	$ 431,608	$ 398,080	$ 2,488,652	$ 1,702,177	$ 1,032,336
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									1,986,786	1,321,807	763,316
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									420,317	320,456	219,596
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									81,549	59,914	49,424
Total revenues outside of the United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									$ 501,866	$ 380,370	$ 269,020

Segment Information - Significa

Segment Information - Significant Customers (Details) - Credit Concentration Risk	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues, Net | Walgreen Co.
Concentration Risk [Line Items]
Concentration risk percentage (less than for CVS/Caremark 2017 revenue)	17.00%	19.00%	20.00%
Revenues, Net | Accredo/Curascript
Concentration Risk [Line Items]
Concentration risk percentage (less than for CVS/Caremark 2017 revenue)	14.00%	15.00%	15.00%
Revenues, Net | CVS/Caremark
Concentration Risk [Line Items]
Concentration risk percentage (less than for CVS/Caremark 2017 revenue)	10.00%	19.00%	17.00%
Accounts Receivable | Walgreen Co.
Concentration Risk [Line Items]
Concentration risk percentage (less than for CVS/Caremark 2017 revenue)	20.00%	15.00%
Accounts Receivable | Accredo/Curascript
Concentration Risk [Line Items]
Concentration risk percentage (less than for CVS/Caremark 2017 revenue)	12.00%	10.00%
Accounts Receivable | CVS/Caremark
Concentration Risk [Line Items]
Concentration risk percentage (less than for CVS/Caremark 2017 revenue)		17.00%

Segment Information - Property

Segment Information - Property and Equipment, Net by Location (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	$ 789,437	$ 698,362
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	753,128	665,552
United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	31,279	26,921
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	5,030	5,889
Total revenues outside of the United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	$ 36,309	$ 32,810

Quarterly Financial Data (un102

Quarterly Financial Data (unaudited) (Details) - USD ($) $ / shares in Units, shares in Thousands	1 Months Ended			3 Months Ended								12 Months Ended
	Jul. 30, 2017	Jul. 31, 2016	Jun. 30, 2015	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues:
Product revenues, net				$ 621,228,000	$ 549,642,000	$ 513,988,000	$ 480,622,000	$ 453,882,000	$ 409,689,000	$ 425,651,000	$ 394,410,000	$ 2,165,480,000	$ 1,683,632,000	$ 1,000,324,000
Royalty revenues				1,345,000	2,231,000	2,861,000	1,551,000	3,887,000	3,835,000	5,282,000	3,596,000	7,988,000	16,600,000	23,959,000
Collaborative revenues				29,061,000	26,292,000	27,286,000	232,545,000	937,000	259,000	675,000	74,000	315,184,000	1,945,000	8,053,000
Total revenues				651,634,000	578,165,000	544,135,000	714,718,000	458,706,000	413,783,000	431,608,000	398,080,000	2,488,652,000	1,702,177,000	1,032,336,000
Costs and expenses:
Cost of product revenues				83,712,000	72,186,000	70,535,000	46,242,000	59,646,000	53,222,000	44,154,000	49,789,000	272,675,000	206,811,000	117,151,000
Royalty expenses				340,000	688,000	670,000	746,000	836,000	855,000	1,098,000	860,000	2,444,000	3,649,000	7,361,000
Research and development expenses				306,664,000	454,947,000	289,451,000	273,563,000	248,452,000	272,370,000	271,008,000	255,860,000	1,324,625,000	1,047,690,000	995,922,000
Sales, general and administrative expenses				134,794,000	120,710,000	127,249,000	113,326,000	109,908,000	106,055,000	111,652,000	105,214,000	496,079,000	432,829,000	376,575,000
Restructuring expenses				387,000	337,000	3,523,000	9,999,000	224,000	8,000	343,000	687,000	14,246,000	1,262,000	2,206,000
Intangible asset impairment charge				0	255,340,000	0	0					255,340,000	0	0
Total costs and expenses				525,897,000	904,208,000	491,428,000	443,876,000	419,066,000	432,510,000	428,255,000	412,410,000	2,365,409,000	1,692,241,000	1,499,215,000
Income (loss) from operations				125,737,000	(326,043,000)	52,707,000	270,842,000	39,640,000	(18,727,000)	3,353,000	(14,330,000)	123,243,000	9,936,000	(466,879,000)
Interest expense, net				(12,547,000)	(13,574,000)	(14,664,000)	(16,765,000)	(20,439,000)	(20,140,000)	(20,155,000)	(20,698,000)	(57,550,000)	(81,432,000)	(84,206,000)
Other (expense) income, net				(748,000)	(77,553,000)	(2,537,000)	(544,000)	1,105,000	(167,000)	(1,219,000)	4,411,000	(81,382,000)	4,130,000	(6,715,000)
Loss before (benefit from) provision for income taxes				112,442,000	(417,170,000)	35,506,000	253,533,000	20,306,000	(39,034,000)	(18,021,000)	(30,617,000)	(15,689,000)	(67,366,000)	(557,800,000)
Provision for (benefit from) income taxes				10,257,000	(125,903,000)	4,337,000	3,985,000	(7,453,000)	503,000	18,130,000	5,485,000	(107,324,000)	16,665,000	30,381,000
Net income (loss)				102,185,000	(291,267,000)	31,169,000	249,548,000	27,759,000	(39,537,000)	(36,151,000)	(36,102,000)	91,635,000	(84,031,000)	(588,181,000)
Loss (income) attributable to noncontrolling interest				(1,501,000)	188,315,000	(13,173,000)	(1,792,000)	5,186,000	696,000	(28,374,000)	(5,529,000)	171,849,000	(28,021,000)	31,847,000
Net income (loss) attributable to Vertex common shareholders				$ 100,684,000	$ (102,952,000)	$ 17,996,000	$ 247,756,000	$ 32,945,000	$ (38,841,000)	$ (64,525,000)	$ (41,631,000)	$ 263,484,000	$ (112,052,000)	$ (556,334,000)
Net income (loss):
Basic (usd per share)				$ 0.40	$ (0.41)	$ 0.07	$ 1.01	$ 0.13	$ (0.16)	$ (0.26)	$ (0.17)	$ 1.06	$ (0.46)	$ (2.31)
Diluted (usd per share)				$ 0.39	$ (0.41)	$ 0.07	$ 0.99	$ 0.13	$ (0.16)	$ (0.26)	$ (0.17)	$ 1.04	$ (0.46)	$ (2.31)
Shares used in per share calculations:
Basic (in shares)				251,557	250,268	247,521	246,024	245,454	244,920	244,482	243,831	248,858	244,685	241,312
Diluted (in shares)				256,804	250,268	251,635	248,700	247,757	244,920	244,482	243,831	253,225	244,685	241,312
Schedule of Collaborative Arrangement Agreements [Line Items]
Collaborative revenues				$ 29,061,000	$ 26,292,000	$ 27,286,000	$ 232,545,000	$ 937,000	$ 259,000	$ 675,000	$ 74,000	$ 315,184,000	$ 1,945,000	$ 8,053,000
Intangible asset impairment charge				0	255,340,000	0	0					255,340,000	0	0
Provision for (benefit from) income taxes				10,257,000	(125,903,000)	4,337,000	3,985,000	$ (7,453,000)	503,000	18,130,000	$ 5,485,000	(107,324,000)	16,665,000	30,381,000
Research and development, early-stage research assets										$ 10,000,000
Merck KGaA
Revenues:
Collaborative revenues												16,600,000
Schedule of Collaborative Arrangement Agreements [Line Items]
Up-front payment							$ 230,000,000					230,000,000
Collaborative revenues												16,600,000
Parion Sciences, Inc
Revenues:
Collaborative revenues					20,000,000	20,000,000
Costs and expenses:
Intangible asset impairment charge					255,300,000
Provision for (benefit from) income taxes					(126,200,000)
Schedule of Collaborative Arrangement Agreements [Line Items]
Up-front payment			$ 80,000,000									85,000,000		80,000,000
Collaborative revenues					20,000,000	$ 20,000,000
Intangible asset impairment charge					255,300,000
Business combination, contingent consideration arrangements, change in amount of contingent consideration, liability					(69,600,000)
Provision for (benefit from) income taxes					(126,200,000)
Janssen
Revenues:
Collaborative revenues				25,000,000
Schedule of Collaborative Arrangement Agreements [Line Items]
Up-front payment															$ 35,000,000
Collaborative revenues				$ 25,000,000
Concert Pharmaceuticals
Schedule of Collaborative Arrangement Agreements [Line Items]
Collaborative arrangement, development and commercialization rights potential maximum milestone payments	$ 160,000,000				160,000,000
Moderna Therapeutics, Inc.
Schedule of Collaborative Arrangement Agreements [Line Items]
Up-front payment		$ 20,000,000							$ 20,000,000
Variable Interest Entity, Primary Beneficiary
Costs and expenses:
Provision for (benefit from) income taxes												(114,090,000)	16,743,000	29,731,000
Loss (income) attributable to noncontrolling interest												171,849,000	(28,021,000)	31,847,000
Schedule of Collaborative Arrangement Agreements [Line Items]
Business combination, contingent consideration arrangements, change in amount of contingent consideration, liability												(62,560,000)	54,850,000	4,530,000
Provision for (benefit from) income taxes												(114,090,000)	16,743,000	29,731,000
Variable Interest Entity, Primary Beneficiary | Parion Sciences, Inc
Revenues:
Collaborative revenues												40,000,000
Costs and expenses:
Provision for (benefit from) income taxes												14,800,000
Schedule of Collaborative Arrangement Agreements [Line Items]
Collaborative revenues												40,000,000
Business combination, contingent consideration arrangements, change in amount of contingent consideration, liability												(63,460,000)	$ 64,800,000	$ 3,660,000
Provision for (benefit from) income taxes												14,800,000
Other Intangible Assets | Variable Interest Entity, Primary Beneficiary | Parion Sciences, Inc
Costs and expenses:
Intangible asset impairment charge					255,300,000							255,300,000
Provision for (benefit from) income taxes												(97,700,000)
Schedule of Collaborative Arrangement Agreements [Line Items]
Intangible asset impairment charge					$ 255,300,000							255,300,000
Provision for (benefit from) income taxes												$ (97,700,000)