GW Pharmaceuticals (GWPRF) 10-K 28 Nov 18 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Sep. 30, 2018	Nov. 12, 2018	Mar. 31, 2018
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Trading Symbol	GWPH
Entity Registrant Name	GW PHARMACEUTICALS PLC
Entity Central Index Key	1,351,288
Current Fiscal Year End Date	--09-30
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		366,515,500
Entity Public Float			$ 3,083,000,000

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Assets
Cash and cash equivalents	$ 354,913	$ 322,154
Accounts receivable, net	2,122	1,367
Inventory	19,061	5,669
Prepaid expenses and other current assets	14,615	35,392
Total current assets	390,711	364,582
Property, plant, and equipment, net	82,381	63,175
Goodwill	6,959	6,959
Deferred tax assets	7,334	6,805
Other assets	3,150	1,401
Total assets	490,535	442,922
Liabilities and stockholders’ equity
Accounts payable	9,741	7,757
Accrued liabilities	46,739	33,656
Current tax liabilities	1,385	1,119
Other current liabilities	804	2,377
Total current liabilities	58,669	44,909
Long-term liabilities:
Capital lease obligations	1,535	1,741
Build-to-suit financing obligation	4,378	4,611
Other liabilities	10,794	10,838
Total long-term liabilities	16,707	17,190
Total liabilities	75,376	62,099
Commitments and contingencies (Note 10)
Stockholders’ equity:
Ordinary shares par value £0.001; 340,246,840 and 304,439,740 shares issued as of September 30, 2018 and 2017, respectively	530	482
Additional paid-in capital	1,246,857	916,726
Accumulated deficit	(757,034)	(461,867)
Accumulated other comprehensive loss	(75,194)	(74,518)
Total stockholders’ equity	415,159	380,823
Total liabilities and stockholders’ equity	$ 490,535	$ 442,922

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - £ / shares	Sep. 30, 2018	Sep. 30, 2017
Statement Of Financial Position [Abstract]
Ordinary shares, par value	£ 0.001	£ 0.001
Ordinary shares, issued	340,246,840	304,439,740

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Revenues
Total revenues	$ 12,737	$ 8,629	$ 12,730
Total revenues	12,737	8,629	12,730
Operating expenses
Cost of product sales	5,986	4,521	3,820
Research and development	153,736	112,249	104,375
Selling, general and administrative	141,818	58,020	33,188
Total operating expenses	301,540	174,790	141,383
Loss from operations	(288,803)	(166,161)	(128,653)
Interest income	3,645	2,063	611
Interest expense	(1,249)	(951)	(244)
Foreign exchange (loss) gain	(4,963)	(6,442)	35,897
Loss before income taxes	(291,370)	(171,491)	(92,389)
Income tax expense (benefit)	3,797	(1,032)	(693)
Net loss	$ (295,167)	$ (170,459)	$ (91,696)
Net loss per common share, basic and diluted	$ (0.88)	$ (0.56)	$ (0.34)
Weighted average common shares outstanding, basic and diluted	333,936	305,826	272,165
Product Net Sales
Revenues
Total revenues	$ 10,469	$ 7,957	$ 7,317
Other Revenue
Revenues
Total revenues	$ 2,268	$ 672	$ 5,413

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (295,167)	$ (170,459)	$ (91,696)
Other comprehensive (loss) gain:
Foreign currency translation adjustments	(676)	10,008	(56,955)
Comprehensive loss	$ (295,843)	$ (160,451)	$ (148,651)

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities
Net loss	$ (295,167)	$ (170,459)	$ (91,696)
Adjustments to reconcile net loss to net cash used in operating activities:
Foreign exchange loss (gain)	4,917	9,280	(35,750)
Stock-based compensation	31,627	15,479	12,661
Depreciation and amortization	9,290	7,054	5,152
Deferred income taxes	(317)	(3,770)	(2,343)
Other	241	1,554	1
Changes in operating assets and liabilities:
Accounts receivable, net	(804)	(277)	(735)
Inventory	(13,646)	5	656
Prepaid expenses and other current assets	14,489	(12,471)	(11,415)
Other assets	(564)
Accounts payable	2,238	3,171	(403)
Current tax liabilities	54	57	432
Accrued liabilities	16,507	1,253	3,397
Other current liabilities	(1,546)	(11)	(80)
Long-term liabilities	813	161	195
Net cash used in operating activities	(231,868)	(148,974)	(119,928)
Cash flows from investing activities
Additions to property, plant and equipment	(31,362)	(19,285)	(12,192)
Additions to capitalized software	(2,042)	(812)	(719)
Proceeds from disposal of property, plant and equipment	517
Net cash used in investing activities	(32,887)	(20,097)	(12,911)
Cash flows from financing activities
Proceeds from issuance of ordinary shares, net of issuance costs	297,931		273,804
Proceeds from exercise of stock options	621	122	972
Payments on build-to-suit financing obligation	(113)	(105)	(21)
Payments on capital leases	(163)	(156)	(157)
Payments on landlord financing obligation	(522)	(1,074)	(337)
Net cash provided by (used in) financing activities	297,754	(1,213)	274,261
Effect of exchange rate changes on cash	(240)	8,993	(13,268)
Net increase (decrease) in cash and cash equivalents	32,759	(161,291)	128,154
Cash and cash equivalents at beginning of period	322,154	483,445	355,291
Cash and cash equivalents at end of period	354,913	322,154	483,445
Supplemental disclosure of cash flow information:
Income taxes paid	3,726	2,928	1,241
Interest paid	1,249	1,232	97
Supplemental disclosure of noncash information:
Property and equipment purchases in accounts payable and accrued liabilities	$ 322	$ 1,793	$ 3,407

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Loss
Beginning balance at Sep. 30, 2015	$ 386,887	$ 424	$ 613,746	$ (199,712)	$ (27,571)
Beginning balance, Shares at Sep. 30, 2015		261,180,000
Issuance of common stock in public offering, net of issuance costs	273,804	$ 52	273,752
Issuance of common stock in public offering, net of issuance costs, Shares		38,640,000
Issuance of common stock from exercise of stock options	972	$ 3	969
Issuance of common stock from exercise of stock Options, Shares		2,273,000
Net loss	(91,696)			(91,696)
Stock-based compensation	12,661		12,661
Other comprehensive loss	(56,955)				(56,955)
Ending balance at Sep. 30, 2016	525,673	$ 479	901,128	(291,408)	(84,526)
Ending balance, Shares at Sep. 30, 2016		302,093,000
Issuance of common stock from exercise of stock options	122	$ 3	119
Issuance of common stock from exercise of stock Options, Shares		2,347,000
Net loss	(170,459)			(170,459)
Stock-based compensation	15,479		15,479
Other comprehensive loss	10,008				10,008
Ending balance at Sep. 30, 2017	380,823	$ 482	916,726	(461,867)	(74,518)
Ending balance, Shares at Sep. 30, 2017		304,440,000
Issuance of common stock in public offering, net of issuance costs	297,932	$ 44	297,888
Issuance of common stock in public offering, net of issuance costs, Shares		33,120,000
Issuance of common stock from exercise of stock options	620	$ 4	616
Issuance of common stock from exercise of stock Options, Shares		2,687,000
Net loss	(295,167)			(295,167)
Stock-based compensation	31,627		31,627
Other comprehensive loss	(676)				(676)
Ending balance at Sep. 30, 2018	$ 415,159	$ 530	$ 1,246,857	$ (757,034)	$ (75,194)
Ending balance, Shares at Sep. 30, 2018		340,247,000

Business Overview

Business Overview	12 Months Ended
	Sep. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Business Overview	Note 1: Business Overview GW Pharmaceuticals plc (the “Company”) is primarily involved in the development of cannabinoid prescription medicines using botanical extracts derived from the Cannabis plant. The Company is developing a portfolio of cannabinoid medicines, of which the lead product is Epidiolex® The Company is a public limited company, which has had American Depository Shares (“ADSs”) registered with the U.S. Securities and Exchange Commission (“SEC”) and has been listed on Nasdaq since May 1, 2013. Until December 5, 2016, the Company was also listed on the Alternative Investment Market (“AIM”), which is a submarket of the London Stock Exchange. The Company is incorporated and domiciled in the United Kingdom. The address of the Company’s registered office and principal place of business is Sovereign House, Vision Park, Histon, Cambridgeshire.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Note 2: Summary of Significant Accounting Policies Basis of Presentation The accompanying consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States (“U.S. GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from these estimates. Foreign Currency Translation The financial position and results of operations of the Company’s non-U.S. subsidiaries are generally determined using local currency as the functional currency. Assets and liabilities of these subsidiaries are translated at the exchange rate in effect at each year end. Income statement accounts are translated at the average rate of exchange prevailing during the year. Adjustments arising from the use of differing exchange rates from period to period are included in accumulated other comprehensive loss in stockholders’ equity. Foreign currency transaction gains and losses are included in “foreign exchange (loss) gain” in the Company’s statements of operations. Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity date of three months or less to be cash equivalents. Fair Value of Financial Instruments The carrying values of the Company’s financial instruments, consisting of cash and cash equivalents, trade receivables, interest and other receivables, and accounts payable and accrued liabilities, approximate fair value due to the relative short-term nature of these instruments. Accounts Receivable Accounts receivable are recorded net of customer allowances for prompt payment discounts, chargebacks, and doubtful accounts. Allowances for prompt payment discounts and chargebacks are based on contractual terms. The Company estimates the allowance for doubtful accounts based on existing contractual payment terms, actual payment patterns of its customers and individual customer circumstances. At September 30, 2018 and 2017, respectively, the Company determined that an allowance for doubtful accounts was not required. No accounts were written off during the periods presented. The Company generally does not allow returns from sales to distributors for reasons not covered under its standard warranty provisions. Inventory Inventory is stated at the lower of cost or estimated net realizable value. The Company uses a combination of standard and actual costing methodologies to determine the cost basis for its inventories which approximates actual cost. Inventory is valued on a first-in, first-out basis. The Company reduces its inventory to net realizable value for potentially excess, dated or obsolete inventory based on an analysis of forecasted demand compared to quantities on hand, as well as product shelf life. The Company capitalizes inventory costs associated with its products upon regulatory approval when, based on management’s judgment, future commercialization is considered probable and the future economic benefit is expected to be realized; otherwise, such costs are expensed. Prior to FDA approval of Epidiolex, all costs related to the manufacturing of Epidiolex were charged to research and development expense in the period incurred. Property, Plant, and Equipment Property and equipment are recorded at cost and depreciated over their estimated useful lives using the straight-line method. Leasehold improvements are amortized over the shorter of their estimated useful lives or the term of the lease by use of the straight-line method. The estimated useful lives for buildings and building improvements range from 4 to 20 years. The estimated useful lives of machinery and equipment range from 3 to 20 years. Construction-in-process reflects amounts incurred for property, equipment or improvements that have not been placed in service. Maintenance and repair costs are expensed as incurred. When assets are retired or sold, the assets and accumulated depreciation are removed from the respective accounts and any gain or loss is recognized. Impairment of Long-Lived Assets The Company reviews its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability is measured by a comparison of the carrying amount of an asset to estimated future operating cash flows expected to be generated by the asset. If the carrying amount of an asset exceeds its estimated future cash flows, an impairment charge is recognized by the amount by which the carrying amount of the asset exceeds the fair value of the asset. Goodwill Goodwill represents the excess of purchase price over fair value of net assets acquired in a business combination and is not amortized. Goodwill is subject to impairment testing at least annually or when a triggering event occurs that could indicate a potential impairment. Revenue Recognition The Company has adopted ASU 2014-09, Revenue from Contracts with Customers (“Topic 606”), Product Net Sales The Company’s product net sales consist of sales of Sativex, which is currently being commercialized for spasticity due to multiple sclerosis (“MS”) outside the United States. The Company has entered into license agreements for the commercialization of Sativex with Almirall S.A. (“Almirall”), in Europe (excluding the United Kingdom) and Mexico; Bayer HealthCare AG (“Bayer”) in the United Kingdom and Canada; Ipsen Biopharm Ltd (“Ipsen”), in Latin America (excluding Mexico and the Islands of the Caribbean); and Neopharm Group (“Neopharm”) in Israel. Under these license agreements, the Company sells fully labeled Sativex vials to its commercial partners for a contractually agreed price, which is generally based on percentages of the commercial partners’ in-market net selling price charged to end customers. Product net sales revenue related to Sativex shipments to commercial license partners is recognized when shipped. The Company commercializes Sativex in Australia and New Zealand through a consignment relationship with a local distributor. Product net sales revenue related to Sativex sales in Australia and New Zealand are recognized when the product is sold through to the end customer. Revenue for the Company’s product sales has not been adjusted for the effects of a financing component as the Company expects, at contract inception, that the period between when the Company’s transfers control of the product and when the Company receives payment will be one year or less. Product shipping and handling costs are included in cost of product sales. Other Revenue The Company’s other revenue primarily consists of research and development fee revenue for research and development services provided under a collaboration agreement with Otsuka Pharmaceutical Co. Ltd (“Otsuka”) The research and development fee revenue is recognized at the time the underlying services are performed. The Sativex license agreements contain provisions for the Company to earn variable consideration in the form of regulatory milestone payments, sales-based milestone payments, and royalty payments. The Company has no further performance obligations related to the regulatory milestone payments and these amounts are recognized in accordance with Topic 606 when receipt of these payments becomes probable and there is no significant risk of revenue reversal. Revenue related to the sales-based milestone payments and product royalty payments are subject to the sales-based royalty exception under Topic 606 and will be recognized when the underlying sales are made. Research and Development Expenses Research and development expenses are charged to operations as incurred. Research and development expenses include, among other things, internal and external costs associated with preclinical development, pre-commercialization manufacturing expenses, and clinical trials. The Company accrues for costs incurred as the services are being provided by monitoring the status of the trial or services provided and the invoices received from its external service providers. In the case of clinical trials, a portion of the estimated cost normally relates to the projected cost to treat a patient in the trials, and this cost is recognized based on the number of patients enrolled in the trial. As actual costs become known, the Company adjusts its accruals accordingly. Research and development expense is presented net of reimbursements from reimbursable tax and expenditure credits from the U.K. government. Prior to September 30, 2017, the Company benefited from the U.K. Small and Medium-sized Enterprise R&D Tax Credit scheme, under which companies are able to obtain a refundable credit of up to 33.4% of eligible research and development expenses incurred by U.K. domiciled entities. Due to the increase in the size of the Company’s employee workforce in the U.K. and annual net revenues, beginning October 1, 2017 the Company is subject to the U.K. R&D Expenditure Credit scheme, available to larger companies, which has a significantly lower credit than the SME scheme. The majority of the Company’s pipeline research, clinical trials management and the Epidiolex and Sativex chemistry and manufacturing controls development activities, which are generally carried out by a subsidiary in the U.K., are eligible for inclusion under the U.K tax and expenditure rebate schemes. For the years ended September 30, 2018, 2017 and 2016, the Company recorded $4.3 million, $26.0 million and $30.5 million, respectively of U.K. tax and expenditure rebates as a component of R&D expense. Concentration Risk Financial instruments, which potentially subject the Company to concentrations of credit risk, principally consist of cash, cash equivalents, investment securities, and accounts receivable. The Company’s cash and equivalents balances are primarily in depository accounts at major financial institutions in accordance with the Company’s investment policy. The Company’s investment policy defines allowable investments and establishes guidelines relating to credit quality, diversification, and maturities of its investments to preserve principal and maintain liquidity. Further, the Company specifies credit quality standards for its customers that are designed to limit the Company’s credit exposure to any single party. The Company’s sales of Sativex outside of the United States are to a limited number of licensed commercial partners. For the year ended September 30, 2018, the Company’s largest customers represented approximately 66% of the Company’s product revenue and 61% of the Company’s accounts receivable balance at September 30, 2018. For the year ended September 30, 2017, the Company’s largest customers represented approximately 68% of the Company’s product revenue and 53% of the Company’s accounts receivable balance at September 30, 2017. Share-based Compensation The Company recognizes share-based compensation expense for grants of stock option and restricted stock awards under the Company's Long-Term Incentive Plans to employees and non-employee members of the Company's board of directors based on the grant-date fair value of those awards. The grant-date fair value of an award is generally recognized as compensation expense over the award's requisite service period. Expense related to awards with graded vesting is generally recognized over the vesting period using the accelerated attribution method. The Company uses the Black-Scholes model to compute the estimated fair value of stock option awards. Using this model, fair value is calculated based on assumptions with respect to (i) expected volatility of the Company's ADS price, (ii) the periods of time over which employees and members of the board of directors are expected to hold their options prior to exercise (expected lives), (iii) expected dividend yield on the ordinary shares, and (iv) risk-free interest rates. Share-based compensation expense also includes an estimate, which is made at the time of grant, of the number of awards that are expected to be forfeited. This estimate is revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. Income Taxes The Company recognizes deferred tax assets and liabilities for temporary differences between the financial reporting basis and the tax basis of the Company's assets and liabilities along with net operating loss and tax credit carryovers. The Company records a valuation allowance against its deferred tax assets to reduce the net carrying value to an amount that it believes is more likely than not to be realized. When the Company establishes or reduces the valuation allowance against its deferred tax assets, its provision for income taxes will increase or decrease, respectively, in the period such determination is made. Valuation allowances against the Company’s deferred tax assets were $97.5 million and $46.1 million at September 30, 2018 and 2017, respectively. Changes in the valuation allowances are generally recognized in the provision for income taxes as a component of the estimated annual effective tax rate. Uncertain tax positions, for which management's assessment is that there is more than a 50% probability of sustaining the position upon challenge by a taxing authority based upon its technical merits, are subjected to certain recognition and measurement criteria. The Company re-evaluates uncertain tax positions and considers various factors, including, but not limited to, changes in tax law, the measurement of tax positions taken or expected to be taken in tax returns, and changes in facts or circumstances related to a tax position. The Company adjusts the level of the liability to reflect any subsequent changes in the relevant facts and circumstances surrounding the uncertain positions. The Company recognizes interest and penalties related to income tax matters in income tax expense. Net Loss Per Share Basic net loss per share is calculated by dividing the net loss by the weighted average number of common shares outstanding for the period, without consideration for common stock equivalents. Diluted net loss per share is computed by dividing the net loss by the weighted average number of common shares and common stock equivalents outstanding for the period determined using the treasury stock method. For purposes of this calculation, market-priced stock options are considered to be common stock equivalents but are not included in the calculations of diluted net loss per share for the periods presented as their effect would be antidilutive. Nominal strike-price options are considered common stock equivalents and are included in the calculation of basic weighted average shares outstanding once they have become vested. The Company incurred net losses for all periods presented and there were no reconciling items for potentially dilutive securities. More specifically, at September 30, 2018, 2017 and 2016, options totaling approximately 13.0 million ordinary shares, 9.9 million ordinary shares and 7.6 million ordinary shares, respectively, were excluded from the calculation of diluted net loss per share as their effect would have been anti-dilutive. Segment and Geographic Reporting Management has determined that the Company operates in one business segment which is the discovery, development and commercialization of novel therapeutics from its proprietary cannabinoid product platform in a broad range of disease areas. Revenues recorded in the years ended September 30, 2018, 2017 and 2016 were generated in the following geographical areas: Years Ended September 30, 2018 2017 2016 (in thousands) Europe $ 6,882 $ 5,447 $ 5,021 United Kingdom 1,761 1,758 1,363 United States 1,560 121 4,917 Canada 1,031 743 955 Asia / Other 1,503 560 474 Total revenues $ 12,737 $ 8,629 $ 12,730 Long-lived assets which include property, plant, and equipment were located as follows: As of September 30, 2018 2017 (in thousands) United Kingdom $ 81,405 $ 62,344 United States 976 831 Total long-lived assets $ 82,381 $ 63,175 Recently Issued Accounting Standards In March 2016, the FASB issued ASU 2016-09, Compensation-Stock Compensation: Improvements to Employee Share-Based Payment Accounting In February 2016, the FASB issued ASU 2016-02, Leases Commitments and Contingencies In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606) Under Topic 606, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of Topic 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. Topic 606 also impacts certain other areas, such as the accounting for costs to obtain or fulfill a contract. The standard also requires disclosure of the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. The Company has adopted this standard using the full-retrospective approach. Revenue for all periods presented in this report is accounted for in accordance with Topic 606. The Company utilized certain practical expedients prescribed by Topic 606 in the adoption of this new accounting standard, including using historical experience to calculate transaction price for the Company’s revenue contracts.

Sativex License Agreements

Sativex License Agreements	12 Months Ended
	Sep. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Sativex License Agreements	Note 3: Sativex License Agreements The Company has entered into six separate license agreements for Sativex the respective partner with exclusive rights in a defined geographic territory to commercialize Sativex in all indications, while the Company retains the exclusive right to manufacture and supply Sativex to license partners on commercial supply terms for the duration of the commercial life of the product. In November 2016, the Company entered into a mutual termination agreement with Novartis Pharma AG (“Novartis”), pursuant to which rights in Sativex in Australia and New Zealand, Asia (excluding Japan, China and Hong Kong), the Middle East (excluding Israel) and Africa will be returned to the Company over an agreed transition period. In December 2017, the Company entered into a mutual termination agreement with Otsuka to return the rights to develop and commercialize Sativex in the United States to the Company. As part of the termination agreement, the Company agreed to pay Otsuka a contingent future milestone payment of $10 million if Sativex achieves FDA approval in the U.S. and a total of $30 million of potential sales-based milestones if U.S. sales of Sativex reach certain thresholds. As of September 30, 2018, no amounts have been accrued related to the contingent payments because it is not probable that the milestones will be achieved. Sativex in the United States In 2007, the Company entered into an exclusive license agreement with Otsuka for the development and commercialization of Sativex in the United States. Under the terms of the agreement, Otsuka was responsible for substantially all development costs and the commercialization of Sativex in the United States. GW was responsible to perform certain Otsuka-funded development activities and supply Sativex to Otsuka. The financial terms of this agreement included an $18.0 million up-front license payment and potential future contingent development, regulatory and commercial milestone payments. GW earned a $4.0 million regulatory milestone payment related to the commencement of the first Phase 3 clinical trial for cancer pain in 2010, but ultimately did not earn any additional milestone payments before the agreement was terminated in December 2017. Sativex in the United Kingdom and Canada In 2003, the Company entered into an exclusive agreement with Bayer to commercialize Sativex in the United Kingdom. This agreement was amended later in 2003 to include Canada. Under the terms of the agreement, GW is the marketing authorization holder for Sativex in the United Kingdom and Canada and is responsible for supplying commercial product to Bayer. The financial terms of the agreement included an upfront fee of $8.2 million, a per-unit supply price, and potential contingent development, regulatory, and sales-based milestone payments. In total, the Company has received $24.2 million in milestone payments from Bayer with the potential to receive a further $11.7 million in future contingent regulatory milestone payments. The Company’s revenue from the supply of Sativex to Bayer equates to a percentage in the mid-thirties to forty percent of Bayer’s in-market net sales price. Sativex in Europe In 2005, the Company entered into an exclusive agreement with Almirall, an international pharmaceutical company with headquarters in Spain, to commercialize Sativex in the European Union (excluding the United Kingdom) and E.U. accession countries, as well as Switzerland, Norway and Turkey. In 2012, this agreement was amended to add Mexico as a licensed territory. In countries where Almirall has no direct presence at the time of product launch, the Company and Almirall will jointly agree on the appointment of distribution partners. In such countries, the Company may elect to distribute the product itself. Under the terms of this agreement, the Company is the marketing authorization holder for Sativex in all countries in the territory, except where local regulations require a locally registered entity to assume this responsibility. The Company is responsible for supplying commercial product to Almirall. The financial terms of the agreement include an up-front license fee of $21.5 million, a per-unit supply price, and $54.6 million in potential contingent regulatory and commercial milestone payments. To date, the Company has received $32.5 million in milestone payments from Almirall with the potential to receive an additional $5.2 million in regulatory and clinical milestones and $16.9 million in sales-based milestones. The Company receives revenue from the supply of Sativex to Almirall, currently equating to a percentage in the low to mid-twenties of Almirall’s in-market net sales price. This percentage will increase to the mid-thirties of net sales price beginning on January 1, 2021. Sativex in Latin America, Asia, the Middle East and Africa In 2011, GW entered into an exclusive agreement with Novartis to commercialize Sativex in Australia and New Zealand, Asia (excluding Japan, China and Hong Kong), the Middle East (excluding Israel) and Africa. Under the terms of the agreement, Novartis held exclusive commercialization rights to Sativex in the licensed territories and acted as the marketing authorization holder for Sativex. GW was responsible for supplying commercial product to Novartis. The financial terms of the agreement included an up-front license fee of $5.0 million from Novartis and potential future milestone payments. In November 2016, the Company entered into a mutual termination agreement with Novartis, pursuant to which rights to Sativex in these territories will return to GW over a transition period. In 2017, GW entered into an agreement with a distributor in Australia and New Zealand for the sale of Sativex In 2014, the Company entered into an exclusive agreement with Ipsen. Under the terms of this agreement, Ipsen will promote and distribute Sativex in Latin America (excluding Mexico and the Islands of the Caribbean). In 2010, the Company entered into an exclusive agreement with Neopharm, an Israeli pharmaceutical company, to commercialize Sativex in Israel. Under the terms of this agreement, Neopharm acts as market authorization holder in the territory and GW is responsible for supplying commercial product to Neopharm. Revenue from the supply of products to Neopharm is expected to equate to forty to fifty percent of Neopharm’s in-market net sales revenue.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	Note 4: Fair Value Measurements At September 30, 2018, the Company’s cash equivalents consisted of money market funds, which are classified as Level 1 within the fair value hierarchy defined by authoritative guidance. At September 30, 2017, the Company’s cash and cash equivalents consisted of short-term cash deposits. Investment securities classified as Level 1 are valued using quoted market prices.

Composition of Certain Balance

Composition of Certain Balance Sheet Captions	12 Months Ended
	Sep. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Composition of Certain Balance Sheet Captions	Note 5: Composition of Certain Balance Sheet Captions: Inventory consisted of the following: September 30, 2018 2017 (in thousands) Raw materials $ 506 $ 267 Work in process 17,529 4,513 Finished goods 1,026 889 $ 19,061 $ 5,669 Property, plant and equipment, net, consisted of the following: September 30, 2018 2017 (in thousands) Build-to-suit property 4,694 4,812 Machinery and equipment 33,303 28,431 Leasehold improvements 36,091 36,063 Office and IT equipment 2,109 2,108 Construction-in-process 34,165 12,319 110,362 83,733 Accumulated depreciation (27,981 ) (20,558 ) $ 82,381 $ 63,175 As a result of the application of build-to-suit lease guidance, the Company has determined that it is the accounting owner of its primary production facility. It is included in the Company’s property, plant and equipment as build-to-suit property. The capitalized amount of the build-to-suit property is equal to the construction costs of the landlord for the shell building. See Note 10—Commitments and Contingencies for additional information. Depreciation of property and equipment was $8.5 million, $7.0 million, and $5.1 million for the years ended September 30, 2018, 2017, and 2016, respectively. During 2018, 2017 and 2016, the Company retired $0.5 million, $1.8 million, and $1.4 million, respectively, of fully depreciated property, plant and equipment. Accrued liabilities consisted of the following: September 30, 2018 2017 (in thousands) Accrued compensation and benefits $ 15,578 6,749 Accrued vendor fees 12,773 8,983 Clinical trial accruals 8,487 6,687 Accrued growing fees 2,890 2,274 Other 7,011 8,963 $ 46,739 $ 33,656 Other liabilities consisted of the following: September 30, 2018 2017 (in thousands) Landlord financing obligation $ 10,368 $ 10,629 Other 426 209 $ 10,794 $ 10,838

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Stockholders' Equity	Note 6: Stockholders’ Equity In December 2017, the Company completed a public offering of 2,760,000 American Depositary Shares (“ADSs”) listed on the Nasdaq Global market, representing 33,120,000 ordinary shares of the Company, at a price of $115.00 per ADS. The net proceeds from this transaction after underwriting discounts and commissions were approximately $297.9 million. In July 2016, the Company completed a public offering of 3,220,000 ADSs listed on the Nasdaq Global market, representing 38,640,000 ordinary shares of the Company at a price of $90.00 per ADS. The net proceeds from this transaction after underwriting discounts and commissions were approximately $273.8 million.

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Sep. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-Based Compensation	Note 7: Share-Based Compensation Stock Plans In March 2008, the Company adopted the GW Pharmaceuticals plc Long-Term Incentive Plan (“the 2008 LTIP Plan”). Share based awards granted by the Company from March 2008 to March 2017 were granted under the 2008 LTIP Plan. On March 14, 2017, the Company adopted the GW Pharmaceuticals plc 2017 Long-Term Incentive Plan (“the 2017 LTIP Plan”). The 2017 LTIP plan authorizes the Company to issue up to an aggregate of 15,000,000 ordinary shares, or 1,250,000 ADSs, related to share-based awards to employees, non-employee directors and consultants. No grants under the 2017 LTIP Plan may be made after March 13, 2022. As of September 30, 2018, 6,583,833 ordinary shares have been or may be issued pursuant to share-based awards that have been granted under the 2017 LTIP Plan. The Company issues new ordinary shares and the commensurate number of ADS when share-based awards are exercised. Provisions of Share-Based Awards The Company issues nominal strike price stock options, which have an exercise price equal to the £0.001 par value per ordinary share of the Company’s ordinary shares, to executive officers, employees and consultants. The Company also issues market-priced options to executive officers and non-employee directors. Nominal strike priced options granted to U.S. residents prior to April 2017 contain short-term expiration provisions so the awards are compliant with provisions of IRS Code 409(a). Nominal strike price options granted to U.S. residents beginning in April 2017 are awarded in the form of RSU-style options that automatically exercise on the vesting date. Substantially all of the share-based awards issued by the Company have service-based vesting conditions. Many awards also have non-market-based performance conditions, which must be achieved within the service-based vesting period for the awards to vest. These performance conditions are generally linked to operational, regulatory or strategic milestones and are designed to incentivize individual employees and advance the Company’s progress towards its strategic objectives. Share-based awards that do not automatically exercise at vest date expire ten years from the date of grant. Share-Based Award Activity The following tables summarize the Company’s stock option activity. The number of options, the weighted average grant date fair value per stock option, and the weighted average exercise price are all on a per ordinary shares basis. The Company’s ADSs that are listed on the Nasdaq Global Market each represent twelve ordinary shares. The following table summarizes the Company’s nominal strike price stock option activity: 2018 2017 2016 Nominal Strike Price Options Weighted Average Grant Date Fair Value Nominal Strike Price Options Weighted Average Grant Date Fair Value Nominal Strike Price Options Weighted Average Grant Date Fair Value (in thousands, except weighted average grant date fair value) Outstanding, beginning of year 9,752 $ 7.90 9,182 $ 5.16 7,334 $ 6.61 Granted 4,247 9.34 3,097 9.66 3,750 4.38 Exercised (2,617 ) 7.21 (2,239 ) 3.21 (1,610 ) 2.05 Cancelled (142 ) 9.37 (288 ) 6.69 (292 ) 4.07 Outstanding, end of year 11,240 $ 8.41 9,752 $ 7.90 9,182 $ 5.16 Exercisable, end of year 1,136 $ 6.11 1,986 $ 4.52 3,058 $ 2.60 The following table summarizes the Company’s market-priced stock option activity: 2018 2017 2016 Market Strike Price Options Weighted Average Exercise Price Market Strike Price Options Weighted Average Exercise Price Market Strike Price Options Weighted Average Exercise Price (in thousands, except weighted average grant date fair value) Outstanding, beginning of year 2,174 $ 8.28 1,452 $ 5.80 1,098 $ 7.89 Granted 785 9.65 830 9.62 1,017 4.09 Exercised (70 ) 9.03 (108 ) 1.15 (663 ) 1.50 Outstanding, end of year 2,889 $ 8.49 2,174 $ 8.28 1,452 $ 5.80 Exercisable, end of year 257 $ 8.74 — — 107 $ 1.17 The weighted average per share fair value of market priced options granted during the years ended September 30, 2018, 2017, and 2016 was $ 5. The aggregate intrinsic value of stock options exercised in 2018, 2017 and 2016 was $ 30.7 22.9 13.1 5.5 5.0 172.74 176.5 16.9 Valuation and Expense Recognition of Share-Based Awards The fair value of stock option awards that do not contain a market condition is estimated using the Black-Scholes option-pricing model. The estimated fair value of each stock option is then expensed over the requisite service period, which is generally the vesting period. The determination of fair value using the Black-Scholes model is affected by the Company’s ADS price as well as assumptions regarding a number of complex and subjective variables, including expected ADS price volatility, risk-free interest rate, expected dividends and projected employee stock option exercise behaviors. Stock options granted during 2018, 2017 and 2016 were valued using the Black-Scholes option-pricing model with the following weighted-average assumptions: Years Ended September 30, 2018 2017 2016 Expected volatility 63 % 69 % 58 % Risk-free interest rate 2.30 % 1.93 % 1.30 % Expected dividend yield 0 % 0 % 0 % Expected life of options in years 6.50 6.50 5.85 The Company estimates its stock price volatility based using a combination of historical stock price volatility and the average implied volatility of options traded in the open market. The risk-free interest rate assumption is based on observed interest rates for the appropriate term of the Company’s stock options. The Company has never declared or paid dividends and has no plans to do so in the foreseeable future. The expected option life assumption is estimated using the simplified method prescribed by ASC 718 and is based on the mid-point between vest date and expiration date since the Company does not have sufficient exercise history to estimate expected option life of historical grants. Compensation expense for share-based awards based on a service condition is recognized only for those awards that are ultimately expected to vest. An estimated forfeiture rate has been applied to unvested awards for the purpose of calculating compensation cost. Forfeitures were estimated based on historical experience. These estimates are revised, if necessary, in future periods if actual forfeitures differ from the estimates. Changes in forfeiture estimates impact compensation cost in the period in which the change in estimate occurs. Compensation expense for share-based awards with graded, service-based vesting conditions is recognized over the requisite service period using the accelerated attribution method. The table below summarizes the total share-based compensation expense included in the Company’s statements of operations for the periods presented (in thousands): Years Ended September 30, 2018 2017 2016 Research and development $ 9,385 $ 5,239 $ 6,586 Sales, general and administrative 22,242 10,240 6,075 $ 31,627 $ 15,479 $ 12,661 As of September 30, 2018, total compensation cost related to non-vested stock options and restricted stock not yet recognized was approximately $49.1 million, which is expected to be recognized over the next 42 months (14 months on a weighted-average basis).

Retirement Plans

Retirement Plans	12 Months Ended
	Sep. 30, 2018
Compensation And Retirement Disclosure [Abstract]
Retirement Plans	Note 8: Retirement Plans The Company operates defined contribution retirement plans in the U.S. and U.K. for the benefit of all qualifying employees. The Company makes discretionary contributions to these plans and contributed $3.3 million, $2.5 million, and $1.9 million in the years ended September 30, 2018, 2017, and 2016, respectively.

Income Taxes

Income Taxes	12 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Note 9: Income Taxes Income (loss) before income taxes is as follows (in thousands): Years Ended September 30, 2018 2017 2016 United States $ 12,041 $ 3,725 $ 2,030 United Kingdom (303,411 ) (175,216 ) (94,419 ) $ (291,370 ) $ (171,491 ) $ (92,389 ) The components of income tax expense (benefit) are as follows (in thousands): Years Ended September 30, 2018 2017 2016 (in thousands) Current U.S. federal $ 3,885 $ 2,676 $ 1,534 U.S. state and local 229 62 116 United Kingdom — — — Total Current $ 4,114 $ 2,738 $ 1,650 Deferred U.S. federal $ (263 ) $ (3,685 ) $ (2,178 ) U.S. state and local (54 ) (85 ) (165 ) United Kingdom — — — Total Deferred $ (317 ) $ (3,770 ) $ (2,343 ) Total income tax expense (benefit) $ 3,797 $ (1,032 ) $ (693 ) As of September 30, 2018, and 2017, respectively, the tax effects of temporary differences and carryforwards that give rise to deferred tax assets and liabilities were as follows: 2018 2017 (in thousands) Deferred tax assets: Net operating losses $ 94,570 $ 46,379 Research and development credits 180 506 Share-based compensation 8,745 7,496 Accrued expenses 2,320 1,787 Other 291 199 Total gross deferred tax assets, net of valuation allowance 106,106 56,367 Valuation allowance (97,462 ) (46,126 ) 8,644 10,241 Deferred tax liabilities: Depreciation $ (1,310 ) $ (2,220 ) Deferred revenue — (1,216 ) Total gross deferred tax liabilities (1,310 ) (3,436 ) Net of deferred tax assets and liabilities $ 7,334 $ 6,805 A valuation allowance of $97.5 million and $46.1 million at September 30, 2018 and 2017, respectively, has been recognized to offset net deferred tax assets where realization of such assets is uncertain. The valuation allowances are primarily related to deferred tax assets for operating loss carryforwards and temporary differences related to share-based compensation expense of the Company’s U.K. operations. On December 22, 2017, the President of the United States signed into law the 2017 Tax Act which, among a broad range of tax reform measures, reduced the U.S. corporate tax rate from 35.0% to 21.0% effective January 1, 2018. The reduction in the U.S. corporate tax rate required the Company’s U.S. subsidiary to remeasure the federal portion of deferred tax assets and liabilities at December 31, 2017 to the enacted tax rate expected to apply when the temporary differences are to be realized. SEC Staff Accounting Bulletin No. 118, “Income Tax Accounting Implications of the Tax Cuts and Jobs Act” (“SAB 118”), allows provisional amounts to be recorded for the tax effects of the 2017 Tax Act when the necessary information is not available, prepared, or analyzed in reasonable detail to finalize its accounting for the changes in the tax law during a measurement period not to extend beyond one year of the enactment date. The Company has provisionally recorded $2.9 million of expense related to the remeasurement of deferred tax assets and liabilities of our U.S. subsidiary. Certain aspects of the Act are still being analyzed which could potentially affect the measurement of these balances or potentially give rise to new deferred tax amounts. The Company expects to finalize its analysis within the measurement period in accordance with SAB 118 after completing reviews of additional guidance issued by the Internal Revenue Service. The following table reconciles the Company’s effective tax rate to the United Kingdom statutory rate: 2018 2017 2016 Tax, computed at the UK statutory rate 19.0 % 19.5 % 20.0 % U.S. research tax credits, net 0.9 % 1.6 % 3.4 % U.K. research tax credits, net (0.1 %) (5.7 %) (12.7 %) Share-based compensation 0.9 % 2.1 % 2.8 % Changes in valuation allowances (20.5 %) (16.2 %) (10.5 %) Overseas profits taxed at different rates (0.3 %) 0.0 % (0.7 %) Remeasurement of deferred taxes from 2017 Tax Act (1.0 %) 0.0 % 0.0 % Other (0.2 %) (0.7 %) (1.6 %) Effective income tax rate (1.3 %) 0.6 % 0.7 % The Company is headquartered in the United Kingdom and has subsidiaries in the United Kingdom and the United States. The Company incurs tax losses in the United Kingdom. The weighted-average U.K. corporate tax rate for the years ended September 30, 2018, 2017, and 2016 was 19.0%, 19.5%, 20.0%, respectively. The United Kingdom’s 2016 Finance Bill, which was enacted on September 15, 2016, contained reductions in corporation tax to 19% from April 1, 2017 and 17% from April 1, 2020. The Company used a 17% tax rate as of September 30, 2018 in respect of the measurement of deferred taxes arising in the United Kingdom, which reflects the currently enacted tax rate based upon the anticipated timing of the unwinding of the deferred tax balances. As of September 30, 2018, the Company had U.K. net operating loss carryforwards of approximately $556.3 million. Unsurrendered U.K. tax losses and tax credit carryforwards can be carried forward indefinitely to be offset against future taxable profits, however this is restricted to an annual £5 million allowance in each standalone company or group and above this allowance, there will be a 50% restriction in the profits that can be covered by losses brought forward. The Company’s subsidiary in the United States has generated taxable profits due to a service agreement between the Company’s subsidiaries in the United States and the United Kingdom. The U.S. federal corporate tax rate for the years ended September 30, 2018, 2017, and 2016 was 24.5%, 35%, and 35%, respectively. The U.S. federal statutory tax rate has decreased due to U.S. Tax Reform which was enacted in December 2017. Unrecognized tax benefits arise when the estimated benefit recorded in the financial statements differs from the amounts taken or expected to be taken in a tax return because of the uncertainties described above. The Company’s total amount of unrecognized tax benefits was $1.8 million, $1.1 million, and $0.9 million at September 30, 2018, 2017, and 2016, respectively. The Company’s policy is to recognize interest and penalties related to uncertain tax positions as a component of income tax expense and unrecognized tax benefits. The amounts accrued for interest and penalty charges as of September 30, 2018, 2017, and 2016 were not significant. If recognized, $1.4 million would affect the effective tax rate. The Company does not anticipate that the amount of unrecognized tax benefits as of September 30, 2018 will significantly change within the next twelve months. The reconciliation of the beginning and ending amount of unrecognized tax benefits was as follows: 2018 2017 2016 (in thousands) Balance at October 1, $ 1,134 $ 884 $ 182 Additions for tax positions related to current year 771 453 702 Additions for tax positions related to prior years 46 18 — Reduction for tax positions related to prior years (125 ) (221 ) — Balance at September 30, $ 1,826 $ 1,134 $ 884

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Sep. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 10: Commitments and Contingencies Leases The Company leases facilities and certain equipment under noncancelable leases that expire at various dates through September 2029. Leases are classified as capital leases when the terms of the lease transfer substantially all of the risk and rewards of ownership to the lease. Other leases are classified as operating leases. In 2018, the Company entered into a master lease agreement giving the Company the ability to lease vehicles under operating leases with initial terms of 50 months from the date of delivery. In connection with this lease agreement, the Company has established a letter of credit for $0.3 million. Property and equipment under capital leases are initially recorded at the lower of asset fair value or the present value of the minimum lease payments on the consolidated balance sheet. The corresponding liability to the lessor is included in the balance sheet as a capital lease obligation. Lease payments under capital leases are treated as debt-service payments and recognized as a reduction of the capital lease obligation and an increase in interest expense. Rent expense for operating leases is recorded on a straight-line basis over the life of the lease term. If an operating lease contains fixed and determinable escalation clauses or rent-free periods, the difference between the rent expense and the rent paid is recorded as deferred rent. Rent expense under the Company’s operating leases was $5.7 million, $4.6 million, and $3.3 million, for the years ended September 30, 2018, 2017, and 2016, respectively. Build-to-Suit Financing Obligation In 2013, the Company entered into an agreement with its landlord for the construction of a new production facility. Under the terms of the agreement, the landlord was responsible for the construction of the cold shell of the building and GW was responsible for the fit out of all internal building systems and improvements. Landlord Financing In conjunction with the build-to-suit property described above, the Company’s landlord provided $13.1 million of funding to the Company for the internal fit out of the production facility. The repayment of this landlord financing takes the form of quarterly rent payments over a 15-year period that commenced in May 2016. The landlord financing liability is accounted for at amortized cost using the effective interest method at a rate of 7.0%. As of September 30, 2018, and 2017, the total landlord financing liability balance was $10.4 million and $11.1 million respectively and included in “other current liabilities” and “other liabilities” in the Company’s consolidated balance sheets. Future lease commitments The aggregate future minimum rent payments under leases in effect as of September 30, 2018, are as follows ( in thousands Lease agreements accounted for as: Capital Leases Operating Leases Build-to-Suit Financing Obligation Landlord Financing Total 2019 $ 229 $ 4,667 $ 495 $ 1,257 $ 6,648 2020 225 4,017 495 1,257 5,994 2021 225 3,381 495 1,257 5,358 2022 225 2,130 495 1,257 4,107 2023 225 808 495 1,257 2,785 Thereafter 900 1,747 6,151 9,334 18,132 Minimum lease commitments $ 2,029 $ 16,750 $ 8,626 $ 15,619 $ 43,024 The Company also enters into short-term agreements with various vendors and suppliers of goods and services in the normal course of operations through purchase orders or other documentation, or that are undocumented except for an invoice. Such short-term agreements are generally outstanding for periods less than a year and are settled by cash payments upon delivery of goods and services. The nature of the work being conducted under these agreements is such that, in most cases, the services may be stopped on short notice. In such event, the Company would not be liable for the full amount of the agreement and are therefore not reflected in the above table. Legal Proceedings As of September 30, 2018, we were not a party to any material legal proceedings.

Financial Statements and Supple

Financial Statements and Supplementary Data (Unaudited)	12 Months Ended
	Sep. 30, 2018
Quarterly Financial Data [Abstract]
Financial Statements and Supplementary Data (Unaudited)	Note 11: Financial Statements and Supplementary Data (Unaudited) The following interim financial information reflects all normal recurring adjustments necessary to fairly present the Company’s quarterly financial results. The summarized quarterly data for the years ended September 30, 2018 and 2017 are as follows: December 31, 2017 March 31, 2018 June 30, 2018 September 30, 2018 Revenue $ 3,992 $ 3,041 $ 3,284 $ 2,420 Operating loss (58,548 ) (68,242 ) (81,406 ) (80,607 ) Net loss attributable to ordinary shareholders (61,816 ) (69,461 ) (84,011 ) (79,879 ) Net loss per ordinary share, basic and diluted (0.20 ) (0.20 ) (0.25 ) (0.23 ) Weighted average shares outstanding, basic and diluted 313,730 340,252 340,457 341,302 December 31, 2016 March 31, 2017 June 30, 2017 September 30, 2017 Revenue $ 2,034 $ 1,381 $ 2,764 $ 2,450 Operating loss (35,801 ) (38,923 ) (43,023 ) (48,414 ) Net loss attributable to ordinary shareholders (20,692 ) (43,266 ) (52,648 ) (53,853 ) Net loss per ordinary share, basic and diluted (0.07 ) (0.14 ) (0.17 ) (0.18 ) Weighted average shares outstanding, basic and diluted 305,216 305,818 306,011 306,263

Subsequent Events

Subsequent Events	12 Months Ended
	Sep. 30, 2018
Subsequent Events [Abstract]
Subsequent Events	Note 12: Subsequent Events In October 2018, the Company completed a public offering of 2,185,000 ADSs listed on the Nasdaq Global market, representing 26,220,000 ordinary shares of the Company at a price of $158.00 per ADS. The net proceeds from this transaction after underwriting discounts and commissions were approximately $324.2 million.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States (“U.S. GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from these estimates.
Foreign Currency Translation	Foreign Currency Translation The financial position and results of operations of the Company’s non-U.S. subsidiaries are generally determined using local currency as the functional currency. Assets and liabilities of these subsidiaries are translated at the exchange rate in effect at each year end. Income statement accounts are translated at the average rate of exchange prevailing during the year. Adjustments arising from the use of differing exchange rates from period to period are included in accumulated other comprehensive loss in stockholders’ equity. Foreign currency transaction gains and losses are included in “foreign exchange (loss) gain” in the Company’s statements of operations.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity date of three months or less to be cash equivalents.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The carrying values of the Company’s financial instruments, consisting of cash and cash equivalents, trade receivables, interest and other receivables, and accounts payable and accrued liabilities, approximate fair value due to the relative short-term nature of these instruments.
Accounts Receivable	Accounts Receivable Accounts receivable are recorded net of customer allowances for prompt payment discounts, chargebacks, and doubtful accounts. Allowances for prompt payment discounts and chargebacks are based on contractual terms. The Company estimates the allowance for doubtful accounts based on existing contractual payment terms, actual payment patterns of its customers and individual customer circumstances. At September 30, 2018 and 2017, respectively, the Company determined that an allowance for doubtful accounts was not required. No accounts were written off during the periods presented. The Company generally does not allow returns from sales to distributors for reasons not covered under its standard warranty provisions.
Inventory	Inventory Inventory is stated at the lower of cost or estimated net realizable value. The Company uses a combination of standard and actual costing methodologies to determine the cost basis for its inventories which approximates actual cost. Inventory is valued on a first-in, first-out basis. The Company reduces its inventory to net realizable value for potentially excess, dated or obsolete inventory based on an analysis of forecasted demand compared to quantities on hand, as well as product shelf life. The Company capitalizes inventory costs associated with its products upon regulatory approval when, based on management’s judgment, future commercialization is considered probable and the future economic benefit is expected to be realized; otherwise, such costs are expensed. Prior to FDA approval of Epidiolex, all costs related to the manufacturing of Epidiolex were charged to research and development expense in the period incurred.
Property, Plant, and Equipment	Property, Plant, and Equipment Property and equipment are recorded at cost and depreciated over their estimated useful lives using the straight-line method. Leasehold improvements are amortized over the shorter of their estimated useful lives or the term of the lease by use of the straight-line method. The estimated useful lives for buildings and building improvements range from 4 to 20 years. The estimated useful lives of machinery and equipment range from 3 to 20 years. Construction-in-process reflects amounts incurred for property, equipment or improvements that have not been placed in service. Maintenance and repair costs are expensed as incurred. When assets are retired or sold, the assets and accumulated depreciation are removed from the respective accounts and any gain or loss is recognized.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company reviews its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability is measured by a comparison of the carrying amount of an asset to estimated future operating cash flows expected to be generated by the asset. If the carrying amount of an asset exceeds its estimated future cash flows, an impairment charge is recognized by the amount by which the carrying amount of the asset exceeds the fair value of the asset.
Goodwill	Goodwill Goodwill represents the excess of purchase price over fair value of net assets acquired in a business combination and is not amortized. Goodwill is subject to impairment testing at least annually or when a triggering event occurs that could indicate a potential impairment.
Revenue Recognition	Revenue Recognition The Company has adopted ASU 2014-09, Revenue from Contracts with Customers (“Topic 606”),
Product Net Sales	Product Net Sales The Company’s product net sales consist of sales of Sativex, which is currently being commercialized for spasticity due to multiple sclerosis (“MS”) outside the United States. The Company has entered into license agreements for the commercialization of Sativex with Almirall S.A. (“Almirall”), in Europe (excluding the United Kingdom) and Mexico; Bayer HealthCare AG (“Bayer”) in the United Kingdom and Canada; Ipsen Biopharm Ltd (“Ipsen”), in Latin America (excluding Mexico and the Islands of the Caribbean); and Neopharm Group (“Neopharm”) in Israel. Under these license agreements, the Company sells fully labeled Sativex vials to its commercial partners for a contractually agreed price, which is generally based on percentages of the commercial partners’ in-market net selling price charged to end customers. Product net sales revenue related to Sativex shipments to commercial license partners is recognized when shipped. The Company commercializes Sativex in Australia and New Zealand through a consignment relationship with a local distributor. Product net sales revenue related to Sativex sales in Australia and New Zealand are recognized when the product is sold through to the end customer. Revenue for the Company’s product sales has not been adjusted for the effects of a financing component as the Company expects, at contract inception, that the period between when the Company’s transfers control of the product and when the Company receives payment will be one year or less. Product shipping and handling costs are included in cost of product sales.
Other Revenue	Other Revenue The Company’s other revenue primarily consists of research and development fee revenue for research and development services provided under a collaboration agreement with Otsuka Pharmaceutical Co. Ltd (“Otsuka”) The research and development fee revenue is recognized at the time the underlying services are performed. The Sativex license agreements contain provisions for the Company to earn variable consideration in the form of regulatory milestone payments, sales-based milestone payments, and royalty payments. The Company has no further performance obligations related to the regulatory milestone payments and these amounts are recognized in accordance with Topic 606 when receipt of these payments becomes probable and there is no significant risk of revenue reversal. Revenue related to the sales-based milestone payments and product royalty payments are subject to the sales-based royalty exception under Topic 606 and will be recognized when the underlying sales are made.
Research and Development Expenses	Research and Development Expenses Research and development expenses are charged to operations as incurred. Research and development expenses include, among other things, internal and external costs associated with preclinical development, pre-commercialization manufacturing expenses, and clinical trials. The Company accrues for costs incurred as the services are being provided by monitoring the status of the trial or services provided and the invoices received from its external service providers. In the case of clinical trials, a portion of the estimated cost normally relates to the projected cost to treat a patient in the trials, and this cost is recognized based on the number of patients enrolled in the trial. As actual costs become known, the Company adjusts its accruals accordingly. Research and development expense is presented net of reimbursements from reimbursable tax and expenditure credits from the U.K. government. Prior to September 30, 2017, the Company benefited from the U.K. Small and Medium-sized Enterprise R&D Tax Credit scheme, under which companies are able to obtain a refundable credit of up to 33.4% of eligible research and development expenses incurred by U.K. domiciled entities. Due to the increase in the size of the Company’s employee workforce in the U.K. and annual net revenues, beginning October 1, 2017 the Company is subject to the U.K. R&D Expenditure Credit scheme, available to larger companies, which has a significantly lower credit than the SME scheme. The majority of the Company’s pipeline research, clinical trials management and the Epidiolex and Sativex chemistry and manufacturing controls development activities, which are generally carried out by a subsidiary in the U.K., are eligible for inclusion under the U.K tax and expenditure rebate schemes. For the years ended September 30, 2018, 2017 and 2016, the Company recorded $4.3 million, $26.0 million and $30.5 million, respectively of U.K. tax and expenditure rebates as a component of R&D expense.
Concentration Risk	Concentration Risk Financial instruments, which potentially subject the Company to concentrations of credit risk, principally consist of cash, cash equivalents, investment securities, and accounts receivable. The Company’s cash and equivalents balances are primarily in depository accounts at major financial institutions in accordance with the Company’s investment policy. The Company’s investment policy defines allowable investments and establishes guidelines relating to credit quality, diversification, and maturities of its investments to preserve principal and maintain liquidity. Further, the Company specifies credit quality standards for its customers that are designed to limit the Company’s credit exposure to any single party. The Company’s sales of Sativex outside of the United States are to a limited number of licensed commercial partners. For the year ended September 30, 2018, the Company’s largest customers represented approximately 66% of the Company’s product revenue and 61% of the Company’s accounts receivable balance at September 30, 2018. For the year ended September 30, 2017, the Company’s largest customers represented approximately 68% of the Company’s product revenue and 53% of the Company’s accounts receivable balance at September 30, 2017.
Stock-based Compensation	Share-based Compensation The Company recognizes share-based compensation expense for grants of stock option and restricted stock awards under the Company's Long-Term Incentive Plans to employees and non-employee members of the Company's board of directors based on the grant-date fair value of those awards. The grant-date fair value of an award is generally recognized as compensation expense over the award's requisite service period. Expense related to awards with graded vesting is generally recognized over the vesting period using the accelerated attribution method. The Company uses the Black-Scholes model to compute the estimated fair value of stock option awards. Using this model, fair value is calculated based on assumptions with respect to (i) expected volatility of the Company's ADS price, (ii) the periods of time over which employees and members of the board of directors are expected to hold their options prior to exercise (expected lives), (iii) expected dividend yield on the ordinary shares, and (iv) risk-free interest rates. Share-based compensation expense also includes an estimate, which is made at the time of grant, of the number of awards that are expected to be forfeited. This estimate is revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates.
Income Taxes	Income Taxes The Company recognizes deferred tax assets and liabilities for temporary differences between the financial reporting basis and the tax basis of the Company's assets and liabilities along with net operating loss and tax credit carryovers. The Company records a valuation allowance against its deferred tax assets to reduce the net carrying value to an amount that it believes is more likely than not to be realized. When the Company establishes or reduces the valuation allowance against its deferred tax assets, its provision for income taxes will increase or decrease, respectively, in the period such determination is made. Valuation allowances against the Company’s deferred tax assets were $97.5 million and $46.1 million at September 30, 2018 and 2017, respectively. Changes in the valuation allowances are generally recognized in the provision for income taxes as a component of the estimated annual effective tax rate. Uncertain tax positions, for which management's assessment is that there is more than a 50% probability of sustaining the position upon challenge by a taxing authority based upon its technical merits, are subjected to certain recognition and measurement criteria. The Company re-evaluates uncertain tax positions and considers various factors, including, but not limited to, changes in tax law, the measurement of tax positions taken or expected to be taken in tax returns, and changes in facts or circumstances related to a tax position. The Company adjusts the level of the liability to reflect any subsequent changes in the relevant facts and circumstances surrounding the uncertain positions. The Company recognizes interest and penalties related to income tax matters in income tax expense.
Net Loss Per Share	Net Loss Per Share Basic net loss per share is calculated by dividing the net loss by the weighted average number of common shares outstanding for the period, without consideration for common stock equivalents. Diluted net loss per share is computed by dividing the net loss by the weighted average number of common shares and common stock equivalents outstanding for the period determined using the treasury stock method. For purposes of this calculation, market-priced stock options are considered to be common stock equivalents but are not included in the calculations of diluted net loss per share for the periods presented as their effect would be antidilutive. Nominal strike-price options are considered common stock equivalents and are included in the calculation of basic weighted average shares outstanding once they have become vested. The Company incurred net losses for all periods presented and there were no reconciling items for potentially dilutive securities. More specifically, at September 30, 2018, 2017 and 2016, options totaling approximately 13.0 million ordinary shares, 9.9 million ordinary shares and 7.6 million ordinary shares, respectively, were excluded from the calculation of diluted net loss per share as their effect would have been anti-dilutive.
Segment and Geographic Reporting	Segment and Geographic Reporting Management has determined that the Company operates in one business segment which is the discovery, development and commercialization of novel therapeutics from its proprietary cannabinoid product platform in a broad range of disease areas. Revenues recorded in the years ended September 30, 2018, 2017 and 2016 were generated in the following geographical areas: Years Ended September 30, 2018 2017 2016 (in thousands) Europe $ 6,882 $ 5,447 $ 5,021 United Kingdom 1,761 1,758 1,363 United States 1,560 121 4,917 Canada 1,031 743 955 Asia / Other 1,503 560 474 Total revenues $ 12,737 $ 8,629 $ 12,730 Long-lived assets which include property, plant, and equipment were located as follows: As of September 30, 2018 2017 (in thousands) United Kingdom $ 81,405 $ 62,344 United States 976 831 Total long-lived assets $ 82,381 $ 63,175
Recently Issued Accounting Standards	Recently Issued Accounting Standards In March 2016, the FASB issued ASU 2016-09, Compensation-Stock Compensation: Improvements to Employee Share-Based Payment Accounting In February 2016, the FASB issued ASU 2016-02, Leases Commitments and Contingencies In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606) Under Topic 606, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of Topic 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. Topic 606 also impacts certain other areas, such as the accounting for costs to obtain or fulfill a contract. The standard also requires disclosure of the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. The Company has adopted this standard using the full-retrospective approach. Revenue for all periods presented in this report is accounted for in accordance with Topic 606. The Company utilized certain practical expedients prescribed by Topic 606 in the adoption of this new accounting standard, including using historical experience to calculate transaction price for the Company’s revenue contracts.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Revenues by Geographic Areas	Revenues recorded in the years ended September 30, 2018, 2017 and 2016 were generated in the following geographical areas: Years Ended September 30, 2018 2017 2016 (in thousands) Europe $ 6,882 $ 5,447 $ 5,021 United Kingdom 1,761 1,758 1,363 United States 1,560 121 4,917 Canada 1,031 743 955 Asia / Other 1,503 560 474 Total revenues $ 12,737 $ 8,629 $ 12,730
Long-lived Assets Includes Property Plant and Equipment	Long-lived assets which include property, plant, and equipment were located as follows: As of September 30, 2018 2017 (in thousands) United Kingdom $ 81,405 $ 62,344 United States 976 831 Total long-lived assets $ 82,381 $ 63,175

Composition of Certain Balanc_2

Composition of Certain Balance Sheet Captions (Tables)	12 Months Ended
	Sep. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Schedule of Inventory	Inventory consisted of the following: September 30, 2018 2017 (in thousands) Raw materials $ 506 $ 267 Work in process 17,529 4,513 Finished goods 1,026 889 $ 19,061 $ 5,669
Schedule of Property, Plant and Equipment, Net	Property, plant and equipment, net, consisted of the following: September 30, 2018 2017 (in thousands) Build-to-suit property 4,694 4,812 Machinery and equipment 33,303 28,431 Leasehold improvements 36,091 36,063 Office and IT equipment 2,109 2,108 Construction-in-process 34,165 12,319 110,362 83,733 Accumulated depreciation (27,981 ) (20,558 ) $ 82,381 $ 63,175
Schedule of Accrued Liabilities	Accrued liabilities consisted of the following: September 30, 2018 2017 (in thousands) Accrued compensation and benefits $ 15,578 6,749 Accrued vendor fees 12,773 8,983 Clinical trial accruals 8,487 6,687 Accrued growing fees 2,890 2,274 Other 7,011 8,963 $ 46,739 $ 33,656
Schedule of Other Liabilities	Other liabilities consisted of the following: September 30, 2018 2017 (in thousands) Landlord financing obligation $ 10,368 $ 10,629 Other 426 209 $ 10,794 $ 10,838

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Sep. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Nominal Strike Price Stock Option Activity	The following table summarizes the Company’s nominal strike price stock option activity: 2018 2017 2016 Nominal Strike Price Options Weighted Average Grant Date Fair Value Nominal Strike Price Options Weighted Average Grant Date Fair Value Nominal Strike Price Options Weighted Average Grant Date Fair Value (in thousands, except weighted average grant date fair value) Outstanding, beginning of year 9,752 $ 7.90 9,182 $ 5.16 7,334 $ 6.61 Granted 4,247 9.34 3,097 9.66 3,750 4.38 Exercised (2,617 ) 7.21 (2,239 ) 3.21 (1,610 ) 2.05 Cancelled (142 ) 9.37 (288 ) 6.69 (292 ) 4.07 Outstanding, end of year 11,240 $ 8.41 9,752 $ 7.90 9,182 $ 5.16 Exercisable, end of year 1,136 $ 6.11 1,986 $ 4.52 3,058 $ 2.60
Summary of Market Priced Stock Option Activity	The following table summarizes the Company’s market-priced stock option activity: 2018 2017 2016 Market Strike Price Options Weighted Average Exercise Price Market Strike Price Options Weighted Average Exercise Price Market Strike Price Options Weighted Average Exercise Price (in thousands, except weighted average grant date fair value) Outstanding, beginning of year 2,174 $ 8.28 1,452 $ 5.80 1,098 $ 7.89 Granted 785 9.65 830 9.62 1,017 4.09 Exercised (70 ) 9.03 (108 ) 1.15 (663 ) 1.50 Outstanding, end of year 2,889 $ 8.49 2,174 $ 8.28 1,452 $ 5.80 Exercisable, end of year 257 $ 8.74 — — 107 $ 1.17
Summary of Stock Options Granted Valued with Weighted-Average Assumptions	Stock options granted during 2018, 2017 and 2016 were valued using the Black-Scholes option-pricing model with the following weighted-average assumptions: Years Ended September 30, 2018 2017 2016 Expected volatility 63 % 69 % 58 % Risk-free interest rate 2.30 % 1.93 % 1.30 % Expected dividend yield 0 % 0 % 0 % Expected life of options in years 6.50 6.50 5.85
Summary of Share-based Compensation Expense Included in Statements of Operations	The table below summarizes the total share-based compensation expense included in the Company’s statements of operations for the periods presented (in thousands): Years Ended September 30, 2018 2017 2016 Research and development $ 9,385 $ 5,239 $ 6,586 Sales, general and administrative 22,242 10,240 6,075 $ 31,627 $ 15,479 $ 12,661

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Summary of Income (Loss) Before Income Taxes	Income (loss) before income taxes is as follows (in thousands): Years Ended September 30, 2018 2017 2016 United States $ 12,041 $ 3,725 $ 2,030 United Kingdom (303,411 ) (175,216 ) (94,419 ) $ (291,370 ) $ (171,491 ) $ (92,389 )
Components of Income Tax Expense (Benefit)	The components of income tax expense (benefit) are as follows (in thousands): Years Ended September 30, 2018 2017 2016 (in thousands) Current U.S. federal $ 3,885 $ 2,676 $ 1,534 U.S. state and local 229 62 116 United Kingdom — — — Total Current $ 4,114 $ 2,738 $ 1,650 Deferred U.S. federal $ (263 ) $ (3,685 ) $ (2,178 ) U.S. state and local (54 ) (85 ) (165 ) United Kingdom — — — Total Deferred $ (317 ) $ (3,770 ) $ (2,343 ) Total income tax expense (benefit) $ 3,797 $ (1,032 ) $ (693 )
Significant Components of Deferred Tax Assets and Liabilities	As of September 30, 2018, and 2017, respectively, the tax effects of temporary differences and carryforwards that give rise to deferred tax assets and liabilities were as follows: 2018 2017 (in thousands) Deferred tax assets: Net operating losses $ 94,570 $ 46,379 Research and development credits 180 506 Share-based compensation 8,745 7,496 Accrued expenses 2,320 1,787 Other 291 199 Total gross deferred tax assets, net of valuation allowance 106,106 56,367 Valuation allowance (97,462 ) (46,126 ) 8,644 10,241 Deferred tax liabilities: Depreciation $ (1,310 ) $ (2,220 ) Deferred revenue — (1,216 ) Total gross deferred tax liabilities (1,310 ) (3,436 ) Net of deferred tax assets and liabilities $ 7,334 $ 6,805
Reconciliation of Effective Tax Rate	The following table reconciles the Company’s effective tax rate to the United Kingdom statutory rate: 2018 2017 2016 Tax, computed at the UK statutory rate 19.0 % 19.5 % 20.0 % U.S. research tax credits, net 0.9 % 1.6 % 3.4 % U.K. research tax credits, net (0.1 %) (5.7 %) (12.7 %) Share-based compensation 0.9 % 2.1 % 2.8 % Changes in valuation allowances (20.5 %) (16.2 %) (10.5 %) Overseas profits taxed at different rates (0.3 %) 0.0 % (0.7 %) Remeasurement of deferred taxes from 2017 Tax Act (1.0 %) 0.0 % 0.0 % Other (0.2 %) (0.7 %) (1.6 %) Effective income tax rate (1.3 %) 0.6 % 0.7 %
Reconciliation of Unrecognized Tax Benefits	The reconciliation of the beginning and ending amount of unrecognized tax benefits was as follows: 2018 2017 2016 (in thousands) Balance at October 1, $ 1,134 $ 884 $ 182 Additions for tax positions related to current year 771 453 702 Additions for tax positions related to prior years 46 18 — Reduction for tax positions related to prior years (125 ) (221 ) — Balance at September 30, $ 1,826 $ 1,134 $ 884

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Sep. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Summary of Aggregate Future Minimum Rent Payments under Leases	The aggregate future minimum rent payments under leases in effect as of September 30, 2018, are as follows ( in thousands Lease agreements accounted for as: Capital Leases Operating Leases Build-to-Suit Financing Obligation Landlord Financing Total 2019 $ 229 $ 4,667 $ 495 $ 1,257 $ 6,648 2020 225 4,017 495 1,257 5,994 2021 225 3,381 495 1,257 5,358 2022 225 2,130 495 1,257 4,107 2023 225 808 495 1,257 2,785 Thereafter 900 1,747 6,151 9,334 18,132 Minimum lease commitments $ 2,029 $ 16,750 $ 8,626 $ 15,619 $ 43,024

Financial Statements and Supp_2

Financial Statements and Supplementary Data (Unaudited) (Tables)	12 Months Ended
	Sep. 30, 2018
Quarterly Financial Data [Abstract]
Summary of Quarterly Data	The summarized quarterly data for the years ended September 30, 2018 and 2017 are as follows: December 31, 2017 March 31, 2018 June 30, 2018 September 30, 2018 Revenue $ 3,992 $ 3,041 $ 3,284 $ 2,420 Operating loss (58,548 ) (68,242 ) (81,406 ) (80,607 ) Net loss attributable to ordinary shareholders (61,816 ) (69,461 ) (84,011 ) (79,879 ) Net loss per ordinary share, basic and diluted (0.20 ) (0.20 ) (0.25 ) (0.23 ) Weighted average shares outstanding, basic and diluted 313,730 340,252 340,457 341,302 December 31, 2016 March 31, 2017 June 30, 2017 September 30, 2017 Revenue $ 2,034 $ 1,381 $ 2,764 $ 2,450 Operating loss (35,801 ) (38,923 ) (43,023 ) (48,414 ) Net loss attributable to ordinary shareholders (20,692 ) (43,266 ) (52,648 ) (53,853 ) Net loss per ordinary share, basic and diluted (0.07 ) (0.14 ) (0.17 ) (0.18 ) Weighted average shares outstanding, basic and diluted 305,216 305,818 306,011 306,263

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details) shares in Millions	12 Months Ended
	Sep. 30, 2018USD ($)Segmentshares	Sep. 30, 2017USD ($)shares	Sep. 30, 2016USD ($)shares
Summary Of Significant Accounting Policies [Line Items]
Accounts receivable written off	$ 0	$ 0
Income tax expenditure rebates of R&D expense	4,300,000	26,000,000	$ 30,500,000
Deferred tax assets, valuation allowance	$ 97,462,000	$ 46,126,000
Number of business segment | Segment	1
Common Stock
Summary Of Significant Accounting Policies [Line Items]
Antidilutive securities excluded from calculation of dulited net loss per share | shares	13	9.9	7.6
Customer Concentration Risk | Product Revenue
Summary Of Significant Accounting Policies [Line Items]
Concentration risk, percentage	66.00%	68.00%
Customer Concentration Risk | Accounts Receivable
Summary Of Significant Accounting Policies [Line Items]
Concentration risk, percentage	61.00%	53.00%
Topic 606
Summary Of Significant Accounting Policies [Line Items]
Performance obligations related to regulatory milestone payments	$ 0
Maximum
Summary Of Significant Accounting Policies [Line Items]
Percentage of research and development refundable credit	33.40%
Buildings and Building Improvements | Minimum
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	4 years
Buildings and Building Improvements | Maximum
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	20 years
Machinery and Equipment | Minimum
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	3 years
Machinery and Equipment | Maximum
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	20 years

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Revenues by Geographical Areas (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Segment Reporting Information [Line Items]
Total revenues	$ 12,737	$ 8,629	$ 12,730
Europe
Segment Reporting Information [Line Items]
Total revenues	6,882	5,447	5,021
United Kingdom
Segment Reporting Information [Line Items]
Total revenues	1,761	1,758	1,363
United States
Segment Reporting Information [Line Items]
Total revenues	1,560	121	4,917
Canada
Segment Reporting Information [Line Items]
Total revenues	1,031	743	955
Asia / Other
Segment Reporting Information [Line Items]
Total revenues	$ 1,503	$ 560	$ 474

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Long-lived Assets Includes Property Plant and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Total long-lived assets	$ 82,381	$ 63,175
United Kingdom
Segment Reporting Information [Line Items]
Total long-lived assets	81,405	62,344
United States
Segment Reporting Information [Line Items]
Total long-lived assets	$ 976	$ 831

Sativex License Agreements - Ad

Sativex License Agreements - Additional Information (Details) - Sativex License Agreements	Jan. 01, 2021	Sep. 30, 2018USD ($)LicenseAgreement	Sep. 30, 2017USD ($)	Sep. 30, 2010	Sep. 30, 2005USD ($)	Sep. 30, 2003USD ($)	Dec. 31, 2017USD ($)	Sep. 30, 2011USD ($)	Sep. 30, 2007USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of license agreements | LicenseAgreement		6
Contingent future milestone payment		$ 10,000,000
Potential sale based milestone		30,000,000
Accrued milestones contingent payments		$ 0
Otsuka Pharmaceutical Co. Ltd | United States
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Up-front payment received									$ 18,000,000
Milestone payment received			$ 4,000,000
Potential additional regulatory and clinical milestones payment receivable							$ 0
Bayer Healthcare AG | United Kingdom and Canada
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Up-front payment received						$ 8,200,000
Milestone payment received						24,200,000
Potential future contingent regulatory milestone payments receivable						$ 11,700,000
Bayer Healthcare AG | United Kingdom and Canada | Revenue from Contract with Customer | Revenue from License Rights Concentration Risk | Minimum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue percentage in-market						15.00%
Bayer Healthcare AG | United Kingdom and Canada | Revenue from Contract with Customer | Revenue from License Rights Concentration Risk | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue percentage in-market						40.00%
Almirall S.A. | Europe
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Up-front payment received					$ 21,500,000
Milestone payment received					32,500,000
Potential additional regulatory and clinical milestones payment receivable					5,200,000
Potential contingent regulatory and commercial milestone payments					54,600,000
Potential additional sales-based milestones payment receivable					$ 16,900,000
Almirall S.A. | Europe | Revenue from Contract with Customer | Revenue from License Rights Concentration Risk | Scenario Forecast
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue percentage in-market	15.00%
Almirall S.A. | Europe | Revenue from Contract with Customer | Revenue from License Rights Concentration Risk | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue percentage in-market					10.00%
Novartis Pharma AG | Latin America, Asia, the Middle East and Africa
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Up-front payment received								$ 5,000,000
Neopharm Group | Latin America, Asia, the Middle East and Africa | Revenue from Contract with Customer | Revenue from License Rights Concentration Risk | Minimum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue percentage in-market				40.00%
Neopharm Group | Latin America, Asia, the Middle East and Africa | Revenue from Contract with Customer | Revenue from License Rights Concentration Risk | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue percentage in-market				50.00%

Composition of Certain Balanc_3

Composition of Certain Balance Sheet Captions - Schedule of Inventory (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Inventory Disclosure [Abstract]
Raw materials	$ 506	$ 267
Work in process	17,529	4,513
Finished goods	1,026	889
Inventory	$ 19,061	$ 5,669

Composition of Certain Balanc_4

Composition of Certain Balance Sheet Captions - Schedule of Property, Plant and Equipment, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 110,362	$ 83,733
Accumulated depreciation	(27,981)	(20,558)
Property, plant and equipment, net	82,381	63,175
Build-to-Suit Property
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	4,694	4,812
Machinery and Equipment
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	33,303	28,431
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	36,091	36,063
Office and IT Equipment
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	2,109	2,108
Construction-in-Process
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 34,165	$ 12,319

Composition of Certain Balanc_5

Composition of Certain Balance Sheet Captions - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Depreciation of property and equipment	$ 8.5	$ 7	$ 5.1
Retired fully depreciated property, plant and equipment	$ 0.5	$ 1.8	$ 1.4

Composition of Certain Balanc_6

Composition of Certain Balance Sheet Captions - Schedule of Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Payables And Accruals [Abstract]
Accrued compensation and benefits	$ 15,578	$ 6,749
Accrued vendor fees	12,773	8,983
Clinical trial accruals	8,487	6,687
Accrued growing fees	2,890	2,274
Other	7,011	8,963
Accrued liabilities	$ 46,739	$ 33,656

Composition of Certain Balanc_7

Composition of Certain Balance Sheet Captions - Schedule of Other Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Other Liabilities Disclosure [Abstract]
Landlord financing obligation	$ 10,368	$ 10,629
Other	426	209
Other liabilities	$ 10,794	$ 10,838

Stockholder's Equity - Addition

Stockholder's Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended		12 Months Ended
	Dec. 31, 2017	Jul. 31, 2016	Sep. 30, 2018	Sep. 30, 2016
Class Of Stock [Line Items]
ADS price per share	$ 115	$ 90
Proceeds from issuance of shares	$ 297.9	$ 273.8
American Depositary Shares ("ADSs")
Class Of Stock [Line Items]
Shares issued	2,760,000	3,220,000
Common Stock
Class Of Stock [Line Items]
Shares issued	33,120,000	38,640,000	33,120,000	38,640,000

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2018USD ($)$ / sharesshares	Sep. 30, 2017USD ($)shares	Sep. 30, 2016USD ($)$ / sharesshares	Sep. 30, 2018£ / shares	Sep. 30, 2017£ / shares	Sep. 30, 2017$ / shares	Mar. 14, 2017shares	Sep. 30, 2015$ / shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares issued | shares	785,000	830,000	1,017,000
Exercise price | £ / shares				£ 0.001	£ 0.001
Weighted average per share fair value of market priced options granted | $ / shares	$ 8.41		$ 5.16			$ 7.90		$ 6.61
Aggregate intrinsic value stock option exercised | $	$ 30.7	$ 22.9	$ 13.1
Weighted average remaining contractual life of option outstanding	5 years 6 months
Weighted average remaining contractual life of option exercisable	5 years
Share price | $ / shares	$ 14.40
Aggregate intrinsic value of options outstanding | $	$ 176.5
Aggregate intrinsic value of options exercisable | $	$ 16.9
American Depositary Shares ("ADSs")
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share price | $ / shares	$ 172.74
2017 LTIP Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Grant expiration date	Mar. 13, 2022
Number of shares issued | shares	6,583,833
2017 LTIP Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized for issuance | shares							15,000,000
2017 LTIP Plan | American Depositary Shares ("ADSs")
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized for issuance | shares							1,250,000
Market Priced Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average per share fair value of market priced options granted | $ / shares	$ 5.98		$ 2.13			$ 6
Non-Vested Stock Options and Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total compensation cost not yet recognized | $	$ 49.1
Total compensation cost expected period of recognition	42 months
Total compensation cost weighted-average basis period	14 months

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Nominal Strike Price Stock Option Activity (Details) - $ / shares shares in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Nominal Strike Price Options, Outstanding, beginning of year	9,752	9,182	7,334
Nominal Strike Price Options, Granted	4,247	3,097	3,750
Nominal Strike Price Options, Exercised	(2,617)	(2,239)	(1,610)
Nominal Strike Price Options, Cancelled	(142)	(288)	(292)
Nominal Strike Price Options, Outstanding, end of year	11,240	9,752	9,182
Nominal Strike Price Options, Exercisable, end of year	1,136	1,986	3,058
Weighted Average Grant Date Fair Value, Outstanding, beginning of year	$ 7.90	$ 5.16	$ 6.61
Weighted Average Grant Date Fair Value, Granted	9.34	9.66	4.38
Weighted Average Grant Date Fair Value, Exercised	7.21	3.21	2.05
Weighted Average Grant Date Fair Value, Cancelled	9.37	6.69	4.07
Weighted Average Grant Date Fair Value, Outstanding, end of year	8.41	7.90	5.16
Weighted Average Grant Date Fair Value, Exercisable, end of year	$ 6.11	$ 4.52	$ 2.60

Share-Based Compensation - Su_2

Share-Based Compensation - Summary of Market Priced Stock Option Activity (Details) - $ / shares shares in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Market Strike Price Options, Outstanding, beginning of year	2,174	1,452	1,098
Market Strike Price Options, Granted	785	830	1,017
Market Strike Price Options, Exercised	(70)	(108)	(663)
Market Strike Price Options, Outstanding, end of year	2,889	2,174	1,452
Market Strike Price Options, Exercisable, end of year	257		107
Weighted Average Exercise Price, Outstanding, beginning of year	$ 8.28	$ 5.80	$ 7.89
Weighted Average Exercise Price, Granted	9.65	9.62	4.09
Weighted Average Exercise Price, Exercised	9.03	1.15	1.50
Weighted Average Exercise Price, Outstanding, end of year	8.49	$ 8.28	5.80
Weighted Average Exercise Price, Exercisable, end of year	$ 8.74		$ 1.17

Share-Based Compensation - Su_3

Share-Based Compensation - Summary of Stock Options Granted Valued with Weighted-Average Assumptions (Details)	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Expected volatility	63.00%	69.00%	58.00%
Risk-free interest rate	2.30%	1.93%	1.30%
Expected dividend yield	0.00%	0.00%	0.00%
Expected life of options in years	6 years 6 months	6 years 6 months	5 years 10 months 6 days

Share-Based Compensation - Su_4

Share-Based Compensation - Summary of Share-based Compensation Expense Included in Statements of Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 31,627	$ 15,479	$ 12,661
Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	9,385	5,239	6,586
Sales, General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 22,242	$ 10,240	$ 6,075

Retirement Plans - Additional I

Retirement Plans - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Defined Contribution Retirement Plan
Defined Contribution Plan Disclosure [Line Items]
Employer discretionary contribution amount to retirement plans	$ 3.3	$ 2.5	$ 1.9

Income Taxes - Summary of Incom

Income Taxes - Summary of Income (Loss) Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Income Tax Disclosure [Abstract]
United States	$ 12,041	$ 3,725	$ 2,030
United Kingdom	(303,411)	(175,216)	(94,419)
Income (loss) before income taxes	$ (291,370)	$ (171,491)	$ (92,389)

Income Taxes - Components of In

Income Taxes - Components of Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Current
U.S. federal	$ 3,885	$ 2,676	$ 1,534
U.S. state and local	229	62	116
Total Current	4,114	2,738	1,650
Deferred
U.S. federal	(263)	(3,685)	(2,178)
U.S. state and local	(54)	(85)	(165)
Total Deferred	(317)	(3,770)	(2,343)
Total income tax expense (benefit)	$ 3,797	$ (1,032)	$ (693)

Income Taxes - Schedule of Defe

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Deferred tax assets:
Net operating losses	$ 94,570	$ 46,379
Research and development credits	180	506
Share-based compensation	8,745	7,496
Accrued expenses	2,320	1,787
Other	291	199
Total gross deferred tax assets, net of valuation allowance	106,106	56,367
Valuation allowance	(97,462)	(46,126)
Total deferred tax assets, net of valuation allowance	8,644	10,241
Deferred tax liabilities:
Depreciation	(1,310)	(2,220)
Deferred revenue		(1,216)
Total gross deferred tax liabilities	(1,310)	(3,436)
Net of deferred tax assets and liabilities	$ 7,334	$ 6,805

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) $ in Thousands, £ in Millions	Apr. 01, 2020	Dec. 22, 2017	Apr. 01, 2017	Sep. 30, 2018USD ($)	Sep. 30, 2018USD ($)	Dec. 31, 2017	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2018GBP (£)	Sep. 30, 2015USD ($)
Income Taxes [Line Items]
Deferred tax assets, valuation allowance				$ 97,462	$ 97,462		$ 46,126
Reduction in corporation tax rate				21.00%		35.00%
Tax cuts and jobs act, incomplete accounting, expense related to remeasurement of deferred tax assets and liabilities					$ 2,900
Weighted-average corporate tax rate					(1.30%)		0.60%	0.70%
Unrecognized Tax Benefits				$ 1,826	$ 1,826		$ 1,134	$ 884		$ 182
Unrecognized tax benefits would impact effective tax rate, if recognized				1,400	$ 1,400
United Kingdom
Income Taxes [Line Items]
Tax, computed at the UK statutory rate					19.00%		19.50%	20.00%
Tax rate used for measurement of deferred tax assets					17.00%
Net operating loss carryforwards				$ 556,300	$ 556,300
Unsurrendered tax losses and tax credit carryforwards to be offset, restricted valuation | £									£ 5
Percentage of restriction in profits covered by losses above restricted valuation amount				50.00%	50.00%				50.00%
United Kingdom | Scenario, Plan
Income Taxes [Line Items]
Tax, computed at the UK statutory rate	17.00%		19.00%
United States
Income Taxes [Line Items]
Weighted-average corporate tax rate					24.50%		35.00%	35.00%
United States | Tax Year 2017 [Member]
Income Taxes [Line Items]
Tax year under examination					2,017
United States | Tax Year 2016 [Member]
Income Taxes [Line Items]
Tax year under examination					2,016
United States | Tax Year 2015 [Member]
Income Taxes [Line Items]
Tax year under examination					2,015
United States | Tax Year 2014 [Member]
Income Taxes [Line Items]
Tax year under examination					2,014
Maximum
Income Taxes [Line Items]
Tax Cuts And Jobs Act 2017 Measurement Period From Enactment Date		1 year

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Effective Tax Rate (Details)	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Investments Owned Federal Income Tax Note [Line Items]
Share-based compensation	0.90%	2.10%	2.80%
Changes in valuation allowances	(20.50%)	(16.20%)	(10.50%)
Overseas profits taxed at different rates	(0.30%)	0.00%	(0.70%)
Remeasurement of deferred taxes from 2017 Tax Act	(1.00%)	0.00%	0.00%
Other	(0.20%)	(0.70%)	(1.60%)
Effective income tax rate	(1.30%)	0.60%	0.70%
United States
Investments Owned Federal Income Tax Note [Line Items]
Research tax credits, net	0.90%	1.60%	3.40%
Effective income tax rate	24.50%	35.00%	35.00%
United Kingdom
Investments Owned Federal Income Tax Note [Line Items]
Tax, computed at the UK statutory rate	19.00%	19.50%	20.00%
Research tax credits, net	(0.10%)	(5.70%)	(12.70%)

Income Taxes - Reconciliation_2

Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Balance at October 1,	$ 1,134	$ 884	$ 182
Additions for tax positions related to current year	771	453	702
Additions for tax positions related to prior years	46	18
Reduction for tax positions related to prior years	(125)	(221)
Balance at September 30,	$ 1,826	$ 1,134	$ 884

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($)	1 Months Ended	12 Months Ended
	May 31, 2016	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2013
Commitments And Contingencies [Line Items]
Lease expiry period		2029-09
Operating leases initial terms		50 months
Rent expense under operating leases		$ 5,700,000	$ 4,600,000	$ 3,300,000
Build-to-suit financing obligation		4,378,000	4,611,000		$ 13,100,000
Build to suit financing obligation rent payments period	15 years
Build to suit financing obligation effective interest rate	7.00%
Build to suit financing, landlord financing obligation		10,400,000	$ 11,100,000
Letter of Credit
Commitments And Contingencies [Line Items]
Maximum borrowing capacity		$ 300,000

Commitments and Contingencies_2

Commitments and Contingencies - Summary of Aggregate Future Minimum Rent Payments under Leases (Details) $ in Thousands	Sep. 30, 2018USD ($)
Capital Leases
2,019	$ 229
2,020	225
2,021	225
2,022	225
2,023	225
Thereafter	900
Minimum lease commitments	2,029
Operating Leases
2,019	4,667
2,020	4,017
2,021	3,381
2,022	2,130
2,023	808
Thereafter	1,747
Minimum lease commitments	16,750
Build-to-Suit Financing Obligation
2,019	495
2,020	495
2,021	495
2,022	495
2,023	495
Thereafter	6,151
Minimum lease commitments	8,626
Landlord Financing
2,019	1,257
2,020	1,257
2,021	1,257
2,022	1,257
2,023	1,257
Thereafter	9,334
Minimum lease commitments	15,619
Total
2,019	6,648
2,020	5,994
2,021	5,358
2,022	4,107
2,023	2,785
Thereafter	18,132
Minimum lease commitments	$ 43,024

Financial Statements and Supp_3

Financial Statements and Supplementary Data (Unaudited) - Summary of Quarterly Data (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Quarterly Financial Data [Abstract]
Total revenues	$ 2,420	$ 3,284	$ 3,041	$ 3,992	$ 2,450	$ 2,764	$ 1,381	$ 2,034	$ 12,737	$ 8,629	$ 12,730
Operating loss	(80,607)	(81,406)	(68,242)	(58,548)	(48,414)	(43,023)	(38,923)	(35,801)	(288,803)	(166,161)	(128,653)
Net loss	$ (79,879)	$ (84,011)	$ (69,461)	$ (61,816)	$ (53,853)	$ (52,648)	$ (43,266)	$ (20,692)	$ (295,167)	$ (170,459)	$ (91,696)
Net loss per common share, basic and diluted	$ (0.23)	$ (0.25)	$ (0.20)	$ (0.20)	$ (0.18)	$ (0.17)	$ (0.14)	$ (0.07)	$ (0.88)	$ (0.56)	$ (0.34)
Weighted average common shares outstanding, basic and diluted	341,302	340,457	340,252	313,730	306,263	306,011	305,818	305,216	333,936	305,826	272,165

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended			12 Months Ended
	Oct. 31, 2018	Dec. 31, 2017	Jul. 31, 2016	Sep. 30, 2018	Sep. 30, 2016
Class Of Stock [Line Items]
ADS price per share		$ 115	$ 90
Proceeds from issuance of shares		$ 297.9	$ 273.8
American Depositary Shares ("ADSs")
Class Of Stock [Line Items]
Issuance of common stock in public offering, net of issuance costs, Shares		2,760,000	3,220,000
Subsequent Event
Class Of Stock [Line Items]
ADS price per share	$ 158
Proceeds from issuance of shares	$ 324.2
Subsequent Event | American Depositary Shares ("ADSs")
Class Of Stock [Line Items]
Issuance of common stock in public offering, net of issuance costs, Shares	2,185,000
Common Stock
Class Of Stock [Line Items]
Issuance of common stock in public offering, net of issuance costs, Shares		33,120,000	38,640,000	33,120,000	38,640,000
Common Stock | Subsequent Event
Class Of Stock [Line Items]
Issuance of common stock in public offering, net of issuance costs, Shares	26,220,000