Summit Therapeutics (SMMT) 20-F 29 Mar 19 2019 FY Annual report (foreign) Financial data

Document and Entity Information

Document and Entity Information Document	12 Months Ended
	Jan. 31, 2019shares
Document And Entity Information [Abstract]
Document type	20-F
Document period end date	Jan. 31, 2019
Amendment flag	false
Registrant name	Summit Therapeutics plc
Central index key	0001599298
Current reporting status	Yes
Current fiscal year end date	--01-31
Filer category	Accelerated Filer
Entity well known seasoned issuer	No
Document fiscal year focus	2019
Document fiscal period focus	FY
Entity common stock shares outstanding	160,389,881

Consolidated Statement of Finan

Consolidated Statement of Financial Position - GBP (£) £ in Thousands	Jan. 31, 2019	Jan. 31, 2018	[1]
Non-current assets
Goodwill	£ 1,814	£ 2,478
Intangible assets	10,604	14,785
Property, plant and equipment	616	809
Non-current assets	13,034	18,072
Current assets
Trade and other receivables	13,547	11,134
Current tax receivable	6,328	4,654
Cash and cash equivalents	26,858	20,102
Current assets	46,733	35,890
Total assets	59,767	53,962
Non-current liabilities
Deferred revenue	(831)	(27,270)
Financial liabilities on funding arrangements	0	(3,090)
Provisions for other liabilities and charges	(1,851)	(1,641)
Deferred tax liability	(1,675)	(2,379)
Non-current liabilities	(4,357)	(34,380)
Current liabilities
Trade and other payables	(8,865)	(8,932)
Deferred revenue and income	(3,374)	(13,834)
Contingent consideration	(629)	0
Current liabilities	(12,868)	(22,766)
Total liabilities	(17,225)	(57,146)
Net assets / (liabilities)	42,542	(3,184)
EQUITY
Share capital	1,604	736
Share premium account	92,806	60,237
Share-based payment reserve	1,148	6,743
Merger reserve	3,027	3,027
Special reserve	19,993	19,993
Currency translation reserve	56	37
Accumulated losses reserve	(76,092)	(93,957)
Total equity / (deficit)	£ 42,542	£ (3,184)
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Consolidated Statement of Compr

Consolidated Statement of Comprehensive Income - GBP (£) £ in Thousands	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	[1]	Jan. 31, 2017
Statement of comprehensive income [abstract]
Revenue	£ 43,012	£ 12,360		£ 2,304
Other operating income	15,156	2,725		72
Operating expenses
Research and development	(39,174)	(28,970)		(18,952)
General and administration	(12,342)	(11,999)		(8,277)
Impairment of goodwill and intangible assets	(3,985)	0		0
Total operating expenses	(55,501)	(40,969)		(27,229)
Operating profit / (loss)	2,667	(25,884)		(24,853)
Finance income	2,788	3,096		8
Finance costs	(424)	(1,164)		(862)
Profit / (loss) before income tax	5,031	(23,952)		(25,707)
Income tax	2,496	3,762		4,336
Profit / (loss) for the year	7,527	(20,190)		(21,371)
Exchange differences on translating foreign operations	19	(13)		29
Other comprehensive income / (loss)
Total comprehensive profit / (loss)	£ 7,546	£ (20,203)		£ (21,342)
Basic and diluted earnings / (loss) per ordinary share from operations (in pounds per share)	£ 0.09	£ (0.31)		£ (0.35)
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Consolidated Statement of Cash

Consolidated Statement of Cash Flows - GBP (£) £ in Thousands	12 Months Ended
	Jan. 31, 2019		Jan. 31, 2018		Jan. 31, 2017
Cash flows from operating activities
Profit / (loss) before income tax	£ 5,031		£ (23,952)	[1]	£ (25,707)
Adjusted for:
Gain on remeasurement or derecognition of financial liabilities on funding arrangements	(539)		(908)	[1]	0
Loss on recognition of contingent consideration payable	754		0	[1]	0
Finance income	(2,788)		(3,096)	[1]	(8)
Finance costs	424		1,164	[1]	862
Unrealized foreign exchange (gain) / loss	(408)		1,960	[1]	711
Depreciation	309		140	[1]	48
Amortization of intangible fixed assets	829		106	[1]	10
Loss on disposal of assets	43		40	[1]	0
Increase / (decrease) in provisions	19		(60)	[1]	12
Research and development expenditure credit	(333)		(23)	[1]	(3)
Impairment of goodwill and intangible assets	3,985		0	[1]	0
Share-based payment	4,743		1,607	[1]	1,379
Adjusted profit / (loss) from operations before changes in working capital	12,069		(23,022)	[1]	(22,696)
(Increase) / decrease in trade and other receivables	(2,218)		(8,993)	[1]	492
(Decrease) / increase in deferred revenue	(36,898)		10,577	[1]	30,527
Increase in trade and other payables	93		3,375	[1]	813
Cash (used by) / generated from operations	(26,954)		(18,063)	[1]	9,136
Taxation received	159		3,374	[1]	3,005
Net cash (used by) / generated from operating activities	(26,795)		(14,689)	[1]	12,141
Investing activities
Acquisition of subsidiaries net of cash acquired	0		(4,775)	[1]	0
Contingent consideration paid	(192)		0		0
Purchase of property, plant and equipment	(119)		(360)	[1]	(81)
Purchase of intangible assets	(6)		(119)	[1]	(7)
Interest received	4		12	[1]	8
Net cash used in investing activities	(313)		(5,242)	[1]	(80)
Financing activities
Proceeds from issue of share capital	34,648		14,931	[1]	0
Transaction costs on share capital issued	(1,313)		(1,428)	[1]	0
Proceeds from exercise of warrants	0		10	[1]	107
Proceeds from exercise of share options	102		392	[1]	283
Cash received from funding arrangements accounted for as financial liabilities	0		0	[1]	23
Net cash generated from financing activities	33,437		13,905	[1]	413
Increase / (Decrease) in cash and cash equivalents	6,329		(6,026)	[1]	12,474
Effect of exchange rates on cash and cash equivalents	427		(1,934)	[1]	(716)
Cash and cash equivalents at beginning of the year	20,102	[1]	28,062	[1]	16,304
Cash and cash equivalents at end of the year	£ 26,858		£ 20,102	[1]	£ 28,062	[1]
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Consolidates Statement Of Chang

Consolidates Statement Of Change In Equity Statement - GBP (£) £ in Thousands		Total	Share capital	Share premium account	Share- based payment reserve	Merger reserve	Special reserve	Currency translation reserve	Accumulated losses reserve
Beginning balance at Jan. 31, 2016		£ 16,080	£ 613	£ 46,035	£ 3,757	£ (1,943)	£ 19,993	£ 21	£ (52,396)
Profit for the year		(21,371)							(21,371)
Currency translation adjustment		29						29
Total comprehensive profit for the year		(21,342)	0	0	0	0	0	29	(21,371)
New share capital issued from exercise of warrants		107	2	105
Share options exercised		283	3	280
Share-based payment		1,379			1,379
Ending balance at Jan. 31, 2017		(3,493)	618	46,420	5,136	(1,943)	19,993	50	(73,767)
Profit for the year	[1]	(20,190)							(20,190)
Currency translation adjustment		(13)						(13)
Total comprehensive profit for the year	[1]	(20,203)						(13)	(20,190)
New share capital issued		14,931	84	14,847
Transaction costs on share capital issued		(1,428)		(1,428)
Issue of ordinary shares as consideration for a business combination		5,000	30			4,970
New share capital issued from exercise of warrants		10	1	9
Share options exercised		392	3	389
Share-based payment		1,607			1,607
Ending balance (Previously reported) at Jan. 31, 2018		9,875	736	60,237	6,743	3,027	19,993	37	(80,898)
Ending balance at Jan. 31, 2018	[1]	(3,184)	736	60,237	6,743	3,027	19,993	37	(93,957)
Profit for the year		7,527							7,527
Currency translation adjustment		19						19	0
Total comprehensive profit for the year		7,546						19	7,527
New share capital issued		34,648	864	33,784
Transaction costs on share capital issued		(1,313)	0	(1,313)
Share options exercised		102	4	98
Share-based payment		4,743			4,743
Transfer					(10,338)				10,338
Ending balance at Jan. 31, 2019		£ 42,542	£ 1,604	£ 92,806	£ 1,148	£ 3,027	£ 19,993	£ 56	£ (76,092)
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Basis of accounting

Basis of accounting	12 Months Ended
	Jan. 31, 2019
Basis Of Presentation [Abstract]
Basis of accounting	Basis of accounting The principal accounting policies adopted by Summit Therapeutics plc and its subsidiaries in the preparation of these financial statements are set out below. These policies have been consistently applied to all the years presented, unless otherwise stated. Basis of preparation The Consolidated Financial Statements have been prepared in accordance with International Financial Reporting Standards and IFRS Interpretations Committee interpretations ('IFRS') as issued by the IASB. The Consolidated Financial Statements have been prepared on a going concern basis and under the historical cost convention modified by revaluation of financial assets and financial liabilities held at fair value through profit and loss. These Consolidated Financial Statements were authorized by the Board of Directors on March 27, 2019. Going concern The financial information in these financial statements has been prepared assuming the Group will continue on a going concern basis. Based on management's forecasts, the Group's existing cash and cash equivalents, anticipated payments from BARDA under its contract for the development of ridinilazole, anticipated payments from CARB-X under its contract for the development of its gonorrhea antibiotic candidate, and anticipated payments from the cost-sharing arrangement under its license and collaboration agreement with Sarepta are expected to be sufficient to enable the Group to fund its operating expenses and capital expenditure requirements through January 31, 2020. The Group will need to raise additional funding in order to support, beyond this date, its planned research and development efforts, potential commercialization related activities, if any of its product candidates receive marketing approval, as well as to support activities associated with operating as a public company in the United States and the United Kingdom. Should the Group be unable to raise additional funding, management has the ability to take mitigating action to fund its operating expenses and capital expenditure requirements in relation to its clinical development activities for only a short period beyond 12 months from the date of issuance of these financial statements. These circumstances represent a material uncertainty which may cast and raise significant doubt on the Group’s ability to continue as a going concern. These financial statements do not contain any adjustments that might result if the Group was unable to continue as a going concern. The Group is evaluating various options to finance its cash needs through a combination of some, or all, of the following: equity offerings, collaborations, strategic alliances, grants and clinical trial support from government entities, philanthropic, non-government and not-for-profit organizations and patient advocacy groups, debt financings, and marketing, distribution or licensing arrangements. Whilst the Group believes that funds would be available in this manner before the end of January 2020, there can be no assurance that the Group will be able to generate funds, on terms acceptable to the Group, on a timely basis or at all, which would impact the Group’s ability to continue as a going concern. The failure of the Group to obtain sufficient funds on acceptable terms when needed could have a material adverse effect on the Group’s business, results of operations and financial condition. Use of estimates The preparation of the financial statements, in conformity with IFRS, requires the use of estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Although these estimates are based on management’s best knowledge of the amount, event or actions, actual results may ultimately differ from those estimates. The areas involving higher degree of judgment or complexity, or areas where assumptions and estimates are significant to the Consolidated Financial Statements are disclosed in Note 2 ‘ Critical accounting judgments and key sources of estimation uncertainty .’ Basis of consolidation The Consolidated Financial Statements incorporate the financial statements of the Group and entities controlled by the Group made up to the reporting date. Control is achieved where the Company has the power to govern the financial and operating policies of an investee entity so as to obtain benefits from its activities. The results of subsidiary undertakings acquired or disposed of in the year are included in the Consolidated Statement of Comprehensive Income from the effective date of acquisition or up to the effective date of disposal, as appropriate. Where necessary, adjustments are made to the financial statements of subsidiaries to bring the accounting policies used into line with those used by the Group. All intra-group transactions, balances, income and expenses are eliminated on consolidation. 1 . Basis of accounting (continued) Revenue recognition Revenue is accounted for in line with principles of IFRS 15 Revenue from contracts with customers . Licensing agreements may consist of multiple elements and provide for varying consideration terms, such as upfront, development, regulatory and sales milestones, sales-based royalties and similar payments. Such arrangements are determined to be within the scope of IFRS 15 and are assessed under the five-step model of the standard to determine revenue recognition. The distinct performance obligations within the contract and the arrangement transaction price are identified. The fair value of the arrangement transaction price is allocated to the different performance obligations based on the relative stand-alone selling price of those services provided and the performance obligation activities to which the terms of the payments specifically relate to. The allocated transaction price is recognized over the respective performance period of each performance obligation. Amounts received in advance of the revenue recognition criteria being met are initially reported as deferred revenue on the Consolidated Statement of Financial Position and are recognized as revenue over the development period. Development and regulatory approval milestone payments are included within the allocated transaction price only when it becomes highly probable that a significant reversal in the amount of cumulative revenue recognized will not occur. Revenues attributable to the development cost share element of a licensing agreement are also recognized over the performance period. Sales-based royalty income and related milestone payments are recognized in the period when the related sales occur or when the relevant milestone is achieved, as the license granted is the predominant element of the performance obligation and the payments are inherently received once the development period is completed and the license granted is useable. See Note 3 ‘ Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers ’ for details of the impact of the initial adoption of IFRS 15. Business Combinations The cost of an acquisition is measured as the fair value of the assets exchanged, equity instruments issued and liabilities incurred or assumed at the date of exchange. Identifiable assets acquired together with liabilities and contingent liabilities assumed in a business combination are measured initially at their fair values at the acquisition date. The excess of the cost of acquisition over the fair value of the identifiable net assets is recorded as goodwill. Goodwill is not amortized but is reviewed for impairment at least annually and more frequently whenever there is an indication of impairment. Intangible Assets In-process research and development that is separately acquired as part of a company acquisition or in-licensing agreement is capitalized even if they have not yet demonstrated technical feasibility, which is usually signified by regulatory approval. Amortization will commence when either products underpinned by the intellectual property rights or the rights themselves become available for use . Intangible assets not subject to amortization are tested for impairment at least annually or whenever there is an indicator of impairment. The intangible asset relating to the acquired Discuva Platform capitalized as part of the acquisition of Discuva Limited in December 2017 is available for use. As such, it is subject to amortization over the period of the relevant associated patents. Other intangible assets are amortized in equal installments over their useful estimated lives as follows: All patents (once filed) Over the period of the relevant patents (assumed to be 20 years) Software licenses 3-5 years Option over non-financial assets Over the period of the relevant agreement 1 . Basis of accounting (continued) Impairment of assets At each year end date, the Group reviews the carrying amounts of its tangible and intangible assets to determine whether there is any indication that those assets have suffered an impairment loss. For the purposes of assessing impairment, assets are grouped at the lowest levels for which there are separately identifiable cash flows (cash-generating units). An impairment loss is recognized for the amount by which the asset’s or cash-generating unit’s carrying amount exceeds its recoverable amount. The recoverable amount is the higher of fair value, reflecting market conditions less costs to sell, and value in use based on an internal discounted cash flow evaluation, where appropriate. Impairment losses recognized for cash-generating units are charged pro rata to the other assets in the cash generating unit. All tangible and intangible assets are subsequently reassessed for indications that an impairment loss previously recognized may no longer exist. See Note 15 ‘ Intangible assets ’ for details. Property, plant and equipment Property, plant and equipment are stated at cost less depreciation. Cost comprises the purchase price plus any incidental costs of acquisition and commissioning. Depreciation is calculated to write-off the cost, less residual value, in equal annual installments over their estimated useful lives as follows: Leasehold improvements Over the period of the remaining lease Laboratory equipment 2-10 years Office and IT equipment 3-5 years The residual value, if not insignificant, is reassessed annually. Financial liabilities on funding arrangements When entering into funding agreements with charitable and not for profit organizations, management is required to assess whether, based on the terms of the agreement, they can avoid a transfer of cash by settling using a non-financial obligation. Under IFRS, when such arrangements also give the counterparties rights over unexploited intellectual property, all or part of the funding agreement should be accounted for as a financial liability recognized in the Statement of Financial Position rather than as a charitable grant. Financial liabilities are initially recognized at fair value using a discounted cash flow model with the difference between the fair value of the liability and the cash received considered to represent a charitable grant. The financial liabilities are subsequently measured at amortized cost using discounted cash flow models which calculate the risk adjusted net present values of estimated potential future cash flows for the relevant project. The financial liabilities are remeasured when there is a specific significant event that provides evidence of a significant change in the probability of successful development such as the completion of a phase of research or public reporting of significant interim data and changes in use or market for a product. The model is updated for changes in the clinical probability of success and other associated assumptions with the discount factor remaining unchanged within the model. Provisions Provisions are recognized when the Group has a present obligation (legal or constructive) as a result of a past event, where it is probable that an outflow of resources will be required to settle the obligation, and where a reliable estimate can be made of the amount of the obligation. If the effect of the time value of money is material, the expected future cash flows will be discounted using a pre-tax risk-free discount rate. Other operating income Other operating income includes income received and recognized from government agencies, philanthropic, non-government, not for profit organizations and patient advocacy groups which are accounted for in accordance with IAS 20, ‘Accounting for Government Grants and Disclosure of Government Assistance.’ Monies received through these means are held as deferred income in the Consolidated Statement of Financial Position and are released to the Consolidated Statement of Comprehensive Income as the underlying expenditure is incurred and to the extent the conditions of the grant are met. 1 . Basis of accounting (continued) Foreign currencies Transactions in foreign currencies are recorded at the rate ruling at the date of the transaction. Monetary assets and liabilities denominated in foreign currencies are translated at the rate of exchange ruling at the year end date. All differences are taken to the Consolidated Statement of Comprehensive Income. Assets and liabilities of subsidiaries that have a functional currency different from the presentation currency (Pound Sterling) are translated at the closing rate at the date of each statement of financial position presented. Income and expenses are translated at average exchange rates. Any resulting differences are recognized in other comprehensive income/(loss) in the Consolidated Statement of Comprehensive Income. Employee benefits All employee benefit costs, notably holiday pay, bonuses and contributions to Group or personal defined contribution pension schemes are charged to the Consolidated Statement of Comprehensive Income on an accruals basis. Operating leases Costs in respect of operating leases are charged to the Consolidated Statement of Comprehensive Income on a straight line basis over the lease term. Assets relating to lease incentives and dilapidation provisions are depreciated over the life of the lease and are included in property, plant and equipment as leasehold improvements. Research and development All ongoing research expenditure is currently expensed in the period in which it is incurred. Due to the regulatory environment inherent in the development of the Group’s products, the criteria for development costs to be recognized as an asset, as set out in IAS 38 ‘ Intangible Assets, ’ are not met until a product has received regulatory approval, and it is probable that future economic benefit will flow to the Group. The Group currently has no qualifying expenditure. Cash and cash equivalents Cash and cash equivalents include cash in hand and deposits held on call with the bank. Share-based payments In accordance with IFRS 2 ‘ Share-based Payment, ’ share options and restricted stock units are measured at fair value at their grant date. The fair value for the majority of the options is calculated using the Black-Scholes formula and charged to the Consolidated Statement of Comprehensive Income on a straight-line basis over the expected vesting period. For those options issued with vesting conditions other than remaining in employment (for example, those conditional upon the Group achieving certain predetermined financial criteria) a simulation model has been used. At each year end date, the Group revises its estimate of the number of options that are expected to become exercisable. This estimate is not revised according to estimates of changes in market based conditions. Current taxation Income tax is recognized or provided at amounts expected to be recovered or paid using the tax rates and tax laws that have been enacted or substantively enacted at the year end date. Current tax includes research and development tax credits which are calculated in accordance with the U.K. research and development tax credit regime applicable to small and medium sized companies. Research and development expenditure which is not eligible for reimbursement under the small and medium sized companies regime, such as expenditure incurred on projects for which we receive income, may be reimbursed under the U.K. Research and Development Expenditure Credit (‘RDEC’) scheme. Receipts under the RDEC scheme are presented within other operating income as they are similar in nature to grant income. 1 . Basis of accounting (continued) Deferred taxation Deferred tax assets and liabilities are recognized where the carrying amount of an asset or liability in the Consolidated Statement of Financial Position differs from its tax base, except for differences arising on: • the initial recognition of goodwill; • the initial recognition of an asset or liability in a transaction which is not a business combination and at the time of the transaction affects neither accounting or taxable profit; and • investments in subsidiaries and jointly controlled entities where the Group is able to control the timing of the reversal of the difference, and it is probable that the difference will not reverse in the foreseeable future. Recognition of deferred tax assets is restricted to those instances where it is probable that taxable profit will be available against which the difference can be utilized. The amount of the asset or liability is determined using tax rates that have been enacted or substantively enacted by the reporting date and are expected to apply when the deferred tax liabilities/(assets) are settled/(recovered). Financial instruments The Group recognizes financial assets and liabilities in the respective categories ‘Financial assets at amortized cost’ and ‘Financial liabilities measured at amortized cost.’ Financial assets at amortized cost are non-derivative financial assets which are held to collect the contractual cash flows on specified dates. They arise when the Group provides money, goods or services directly to the debtor with no intention of trading the receivable. They are included in current assets, except for maturities greater than 12 months after the year end date, which are classified as non-current assets. Other liabilities consist of trade and other payables, being balances arising in the course of normal business with suppliers, contractors and other service providers, and borrowings, being loans and hire purchase funds advanced for the refit of leasehold premises and the purchase of laboratory equipment, fixtures and fittings. Financial assets at amortized cost, and other liabilities are initially recorded at fair value, and thereafter at amortized cost, if the timing difference is deemed to impact the fair value of the asset or liability. The Group assesses at each year end date the expected credit losses of a financial asset or a group of financial assets with consideration given to the risk of default occurring. Expected credit losses are the difference between the contractual cash flows due to the Group and the cash flows the Group expects to receive. The Group does not hold or trade in derivative financial instruments. Warrants Warrants issued by the Group are recognized and classified as equity when upon exercise, the Company would issue a fixed amount of its own equity instruments (ordinary shares) in exchange for a fixed amount of cash or another financial asset. Consideration received, net of incremental costs directly attributable to the issue of such new warrants, is shown in equity. Such warrants are not remeasured at fair value in subsequent reporting periods.

Critical accounting judgements

Critical accounting judgements and key sources of estimation uncertainty	12 Months Ended
	Jan. 31, 2019
Disclosure of changes in accounting estimates [abstract]
Critical accounting judgements and key sources of estimation uncertainty	Critical accounting judgments and key sources of estimation uncertainty The preparation of the Consolidated Financial Statements requires the Group to make judgments, estimates and assumptions that affect the application of accounting policies and the reported amounts of assets and liabilities, income and expense. Actual results may differ from those estimates. Critical Judgments in Applying the Group’s Accounting Policies The following are the critical judgments, apart from those involving estimations, that the Directors have made in the process of applying the Group’s accounting policies and that have the most significant effect on the amounts recognized in the Consolidated Financial Statements. Financial liabilities on funding arrangements Financial liabilities on funding arrangements are remeasured and the Group is required to apply judgment, when there is a specific significant event that provides evidence of a significant change in the probability of successful development such as the completion of a phase of research or changes in use or market for a product. All remaining financial liabilities have been remeasured to £nil during the financial year, see Note 21 ‘ Financial liabilities on funding arrangements ’ for further details. Revenue Recognition The Group recognizes revenue from licensing fees, collaboration fees, development, regulatory and approval milestone fees, sales milestones and sales-based royalties. Agreements generally include a non-refundable upfront fee, milestone payments, the receipt of which is dependent upon the achievement of certain clinical, regulatory or commercial milestones, as well as royalties on product sales of licensed products, if and when such product sales occur. For these agreements, the Group is required to apply judgment as follows: the identification of the number of performance obligations within a contract, the allocation of the transaction price to those performance obligations and the timing of when milestone payments are included in the transaction price. In relation to the license and collaboration agreement with Sarepta and the license and commercialization agreement with Eurofarma, the Group has assessed that the license to commercialize the Group’s intellectual property is not distinct in the context of the contract and that there is a transformational relationship between the license and the research and development activities delivered as they are highly interrelated elements of the contract. The Group has therefore determined that there is one single performance obligation under IFRS 15 in relation to the license granted and research and development activities which is the transfer of a license for which the associated research and development activities are completed over time. In the case of the Sarepta agreement, management assessed that there were a number of further performance obligations being the research and clinical development activities relating to the future generation small molecule utrophin modulators, the license granted to commercialize in Latin America at the option of Sarepta, and the wind-down activities of terminated clinical trials. These performance obligations are separate and distinct from the transfer of a license for which the associated research and development activities are completed over time. The allocation of the transaction price is based on the relative stand-alone selling price of those services provided and the performance obligation activities to which the terms of the payments specifically relate. Milestone payments and other variable consideration are only included in the transaction price allocated to a performance obligation when it becomes highly probable that a significant reversal in the amount of cumulative revenue recognized will not occur. The allocated transaction price is recognized over the respective performance period of each performance obligation. As a result, the upfront payments, development milestones and development cost share income allocated to the license granted and research and development activities, which is the transfer of a license for which the associated research and development activities are completed over time, are initially reported as deferred revenue in the Consolidated Statement of Financial Position and are recognized as revenue over the development period. See Note 3 ‘ Changes to accounting policies -Adoption of IFRS 15 Revenue from contracts with customers ’ for details of the impact of the initial adoption of IFRS 15 and Note 5 ' Revenue ' for details of our contracts with customers. Indications of asset impairment The Group is required to exercise judgment as to whether there is any indication that its tangible and intangible assets have suffered an impairment loss when reviewing the carrying value of those assets. See Note 15 ' Intangible assets ' for details of the impairment reviews performed by the Group relating to this financial year. 2 . Critical accounting judgments and key sources of estimation uncertainty (continued) Key sources of estimation uncertainty The key assumptions concerning the future, and other key sources of estimation uncertainty at the year end date that may have a risk of causing a material adjustment to the carrying amounts of assets and liabilities within the next financial year, are noted below. Recognition of research and development expenditure and associated funding income The Group recognizes expenditure incurred in carrying out its research and development activities and the associated funding income in line with management’s best estimation of the work completed on each separately contracted study or activity. This includes the calculation of research and development accruals and prepayments at each period to account for expenditure that has been incurred and the associated funding income. This requires estimations of the expected costs to complete each study or activity and the estimation of the current stage of completion. In all cases, the full cost of each study or activity is expensed by the time the final report or where applicable, product, has been received. See Notes 17 ' Trade and other receivables ' and 18 ' Trade and other payables ' for further details of these estimates. Assumed contingent liability The Group's assumed contingent liability is recognized in the Consolidated Financial Statements at fair value as required by IFRS 3 Business Combinations . In determining the fair value of this liability, a number of assumptions need to be made by management which include significant estimates. See Note 23 ‘ Provisions for other liabilities and charges and contingent liabilities .’

Changes to accounting policies

Changes to accounting policies	12 Months Ended
	Jan. 31, 2019
Disclosure of expected impact of initial application of new standards or interpretations [abstract]
Changes to accounting policies	Changes to accounting policies Adoption of IFRS 15 Revenue from contracts with customers IFRS 15 establishes comprehensive guidelines for determining when to recognize revenue and how much revenue to recognize. The Group adopted this new standard effective February 1, 2018, as required, using the full retrospective transition method in accordance with IAS 8 Accounting Policies, Changes in Accounting Estimates and Errors . The core principle in that framework is that a company should recognize revenue to depict the transfer of control of promised goods or services to the customer in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. To determine revenue recognition for arrangements that a company determines are within the scope of IFRS 15, a company 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 company satisfies a performance obligation. The Group assessed the effect of adoption of this standard as it relates to the license and collaboration agreement with Sarepta (the 'Sarepta Agreement') and the license and commercialization agreement with Eurofarma (the 'Eurofarma Agreement'). The Sarepta Agreement and the Eurofarma Agreement grant the rights in specific territories to commercialize products in the Group’s utrophin modulator pipeline and ridinilazole, respectively, as well as the provision of the associated research and development activities. Such activities result in a service that is the output of the Group’s ordinary activities. The Group assessed that the revenues from these agreements are in the scope of IFRS 15. 3 . Changes to accounting policies (continued) For both of these agreements, the Group assessed that the license to commercialize the Group’s intellectual property is not distinct in the context of the contract and that there is a transformational relationship between the license and the research and development activities delivered as they are highly interrelated elements of the contract. The Group therefore determined that there is one single performance obligation under IFRS 15 in relation to the license granted and the research and development activities, which is the transfer of a license for which the associated research and development activities are completed over time. The transaction price of these agreements includes upfront payments, development and regulatory milestone payments, development cost share income, sales milestones and sales-based royalties. Milestone payments are included in the transaction price only when it becomes highly probable that a significant reversal in the amount of cumulative revenue recognized will not occur . The relevant transaction price elements are allocated to the performance obligation identified being the transfer of a license for which the associated research and development activities are completed over time. The revenues are recognized over the development period using an output method based on time elapsed, reflecting both the increase in value of the license and the progression of the research and development activities over the development period towards potential commercialization of the product . Sales milestones and sales-based royalties are not included in the Group’s revenues when the associated clinical program is still in development. The predominant element of the performance obligation that the sales milestones and sales-based royalties relate to is the license granted and hence the revenues are recognized when the related sales occur. The Sarepta Agreement also has a number of further performance obligations, including research and clinical development activities relating to the future generation small molecule utrophin modulators and the license granted to commercialize in Latin America, which is at the option of Sarepta. The development, regulatory and sales milestone payments allocated to the future generation candidate activities and Latin America license granted are contingent on future activities, and, as a result, would only be included in the transaction price and accounted for as revenue when it would be highly probable that a significant reversal in the amount of cumulative revenue recognized would not occur. The relevant sales-based royalties would be recognized when the related sales occur, as the license granted is the predominant element of the performance obligation. The development cost share income allocated to clinical trial wind-down activities, which is also a separate performance obligation within the Sarepta Agreement, are recognized using an input method based on costs incurred. Due to the adoption of IFRS 15, the $22.0 million ( £17.2 million ) development milestone payment the Group received in May 2017 as part of the Sarepta Agreement, which had previously been recognized in full under IAS 18 during the Group's fiscal year ended January 31, 2018, was recognized as revenue over the development period. Similarly, development cost share income from Sarepta which commenced from January 1, 2018, under the agreement was recognized as revenue over the development period. As a result of this change, £13.1 million of income related to the Sarepta Agreement previously recognized as revenue during the year ended January 31, 2018, was classified as deferred revenue in the opening Statement of Financial Position as at February 1, 2018. The adjustment consisted of (i) £12.4 million related to the development milestone payment; and (ii) £0.7 million related to development cost share income related to Sarepta’s share of research and development costs incurred in January 2018 (the first month that the cost share component of the agreement was in effect). In June 2018, the Group announced the discontinuation of the development of ezutromid after its Phase 2 clinical trial, PhaseOut DMD, did not meet its primary or secondary endpoints. As a result, the Group updated the development period over which the Sarepta revenues allocated to the license and the research and development activities performance obligation were recognized, with the development period deemed to have concluded in June 2018 in line with when development of ezutromid was discontinued. This resulted in all revenues relating to the Sarepta Agreement that were previously deferred in the Statement of Financial Position being released in full during the year ended January 31, 2018. The Group continues to receive cost share income from Sarepta, at 45% of eligible costs, including for wind-down activities for the ezutromid clinical trial. This cost share income is recognized as revenue when such costs are incurred. The Group does not expect to receive any further milestone payments from Sarepta. The Group’s assessment resulted in there being no difference in the accounting treatment of the Eurofarma Agreement under IAS 18 and IFRS 15. Revenues recognized relating to the agreement during the year ended January 31, 2018, under IAS 18 related only to the upfront payment, which was initially reported as deferred revenue in the Statement of Financial Position and is being recognized as revenue over the development period. This is consistent with the accounting treatment under IFRS 15. This change in accounting policy has been reflected retrospectively in the comparative Statement of Financial Position, the comparative Statement of Comprehensive Income, the comparative Statement of Cash Flows and the comparative Statement of Changes in Equity for the year ended January 31, 2018 . The opening Statement of Financial Position as at February 1, 2017, is in line with comparative amounts disclosed in the financial statements for the year ended January 31, 2017, as there was no impact of this change in accounting policy on the Statement of Financial Position as at January 31, 2017. 3 . Changes to accounting policies (continued) The impact of this change in accounting policy on the comparatives to these financial statements was an increase in non-current and current deferred revenue, an increase in accumulated losses reserve, a reduction in revenue historically recognized, and a presentational change to the Statement of Cash Flows. The increase in non-current and current deferred revenue for the year ended January 31, 2018, and reduction in revenue recognized during the year ended January 31, 2018 , relate to the difference between the accounting treatment of the Sarepta development milestone payment and development cost share income under IAS 18 and IFRS 15, as described above, which is recognized as revenue over the remainder of the determined development period. Original Year ended January 31, 2018 Adjusted Year ended January 31, 2018 Impact Impact on Consolidated Statement of Financial Position £000s £000s £000s Non-current liabilities Deferred revenue (18,033 ) (27,270 ) (9,237 ) Current liabilities Deferred revenue (10,012 ) (13,834 ) (3,822 ) Equity Accumulated losses reserve (80,898 ) (93,957 ) (13,059 ) Original Year ended January 31, 2018 Adjusted Year ended January 31, 2018 Impact Impact on Consolidated Statement of Comprehensive Income £000s £000s £000s Revenue 25,419 12,360 (13,059 ) Loss for the year (7,131 ) (20,190 ) (13,059 ) Original Adjusted Impact Impact on Consolidated Statement of Cash Flows £000s £000s £000s Loss before income tax (10,893 ) (23,952 ) (13,059 ) Adjusted for: (Decrease) / increase in deferred revenue (2,482 ) 10,577 13,059 Impact on net cash used by operating activities (13,375 ) (13,375 ) — The Group will continue to monitor interpretations released by the IFRS Interpretations Committee and amendments to IFRS 15 and, as appropriate, will adopt these from the effective dates. For details of revenue recognition during the year ended January 31, 2019 , see Note 5 ' Revenue .' Adoption of IFRS 9 Financial Instruments The Group adopted IFRS 9 Financial Instruments effective February 1, 2018. There has been no impact on the Group’s net results or net assets for the year ended January 31, 2019 , and 2018 as a result of adoption. Impact assessment of IFRS 16 Leases IFRS 16 specifies how to recognize, measure, present and disclose leases. The standard provides a single lessee accounting model, requiring lessees to recognize assets and liabilities for all leases unless the lease term is 12 months or less or the underlying asset has a low value. The standard is effective for reporting periods beginning on or after January 1, 2019, and replaces the accounting standard IAS 17 Leases . Two adoption methods are permitted for transition: retrospectively to all prior reporting periods presented in accordance with IAS 8 Accounting Policies, Changes in Accounting Estimates and Errors , with certain practical expedients permitted; or retrospectively with the cumulative effect of initially applying the standard recognized at the date of initial application. 3 . Changes to accounting policies (continued) At inception of a contract, a company assesses whether a contract is, or contains, a lease based on whether the contract conveys the right to control the use of an identified asset for a period of time in exchange for consideration. A right-of-use asset and a lease liability are recognized at the lease commencement date. The right-of-use asset is initially measured based on the initial amount of the lease liability adjusted for any lease payments made at or before the commencement date, plus any initial direct costs incurred and an estimate of costs to dismantle and remove the underlying asset or to restore the underlying asset or the site on which it is located, less any lease incentives received. The assets are depreciated to the earlier of the end of the useful life of the right-of-use asset or the lease term using the straight-line method. The lease term includes periods covered by an option to extend if it is reasonably certain to exercise that option and period covered by an option to terminate if it is reasonably certain not to exercise that option. The lease liability is initially measured at the present value of the lease payments that are not paid at the commencement date, discounted using the interest rate implicit in the lease or, if that rate cannot be readily determined, the applicable incremental borrowing rate. The lease liability is subsequently measured at amortized cost using the effective interest method and is remeasured when there is a change in future lease payments or if the assessment of whether a company will exercise a purchase, extension or termination option. The Group has elected to adopt this new standard effective February 1, 2019, as required, using the full retrospective transition method in accordance with IAS 8 Accounting Policies, Changes in Accounting Estimates and Errors . Under this method, the Group will adjust its results for the years ended January 31, 2018, and 2019, and applicable interim periods, as if IFRS 16 had been effective for those periods. To date, the Group has assessed the effect of adoption of this standard as it relates to its leased properties in Oxford and Cambridge, U.K., and has concluded that any other contracts are not within the scope of IFRS 16 or are of low value, for which the Group has elected not to apply the requirement of IFRS 16. Currently, the Group anticipates the effects of adoption of IFRS 16 to be as described below. Estimated impacts from the adoption could differ upon the final adoption and implementation of the standard. The adoption of IFRS 16 is not expected to have a significant impact on the Group’s net results or net assets. The Group expects the accounting for the right-of-use asset and lease liability to be the most significant change in accounting for leases. The Group will no longer recognize a lease incentive accrual and will be required to reclassify some costs from research and development expenses and general and administration expenses to finance costs, being the interest expense on lease liabilities. In addition, some amounts previously presented as cash flows from operating activities in the Group's Consolidated Statement of Cash Flows will be presented as cash flows from financing activities. The Group has performed an evaluation of the expected effect of adoption on the accounting for the U.K. leased properties. The Group currently estimates the effect to the financial statements for the year ended January 31, 2019, after the adoption of IFRS 16 will be an increase in both gross assets and liabilities of £0.9 million . The quantitative amount provided above is an estimate of the expected effects of the Group’s adoption of IFRS 16. This amount represents management’s best estimates of the effects of adopting IFRS 16 at the time of the preparation of these financial statements. The actual quantitative effects of the adoption of IFRS 16 are subject to change from these estimates and such change may be significant, pending the completion of the Group’s assessment in the first quarter to April 30, 2019. The Directors do not expect that the adoption of the remaining standards and interpretations in future periods will have a material impact on the financial statements of the Group. During the year ended January 31, 2019 , the following additional new standards, amendments to standards or interpretations became effective for the first time. The adoption of these interpretations, standards or amendment to standards were either not relevant for the Group or have not led to any significant impact on the Group’s financial statements. International Accounting Standards (IAS/IFRS) Effective Date IFRS 9 Financial Instruments (as revised in 2014) January 1, 2018 Amendment to IFRS 2 Share Based Payments, Classification and Measurement of Share-based Payment Transactions January 1, 2018 Amendments resulting from Annual Improvements 2014–2016 Cycle January 1, 2018 IFRIC 22 Foreign Currency Transactions and Advance Consideration January 1, 2018 3 . Changes to accounting policies (continued) At the date of signing these Consolidated Financial Statements, the following standards, amendments and interpretations, which have not been applied in these financial statements, were in issue but not yet effective: International Accounting Standards (IAS/IFRS) Effective Date IFRS 16 Leases January 1, 2019 Amendments to IFRS 9 Financial Instruments, Prepayment Features with Negative Compensation January 1, 2019 Amendments to IAS 19 Employee Benefits, Plan amendments, curtailments or settlements January 1, 2019 Amendments resulting from Annual Improvements 2015–2017 Cycle January 1, 2019 IFRIC 23 Uncertainty over Income Tax Treatments January 1, 2019 Amendments to References to the Conceptual Framework in IFRS Standards January 1, 2020 Amendments to IFRS 3 Business Combinations, Definition of a Business January 1, 2020

Segmental reporting

Segmental reporting	12 Months Ended
	Jan. 31, 2019
Disclosure of operating segments [abstract]
Segmental reporting	Segmental reporting The Summit Group comprises eleven legal entities, of which four are trading. These included the ten subsidiary companies and the Group holding company, Summit Therapeutics plc. The Group operates in one reportable segment: Drug Development. The chief operating decision-maker has been identified as the Executive Management Team consisting of the Chief Executive Officer, the Chief Financial Officer (prior to his departure in December 2018), the Chief Operating Officer and the Chief Commercial Officer. The Executive Management Team reviews the consolidated operating results regularly to make decisions about the financial and organizational resources and to assess overall performance. The Drug Development segment covers Summit’s research and development activities carried out by the Group, primarily comprising the CDI program, antibiotic pipeline research activities and the DMD program. The corporate and other activities of Summit Therapeutics plc, Summit (Oxford) Limited, Summit Therapeutics Inc and Discuva Limited, which comprise the costs incurred in providing the facilities, finance, human resource and information technology services, are incurred by the main segment of the Group. Substantially all of the Group’s assets are held in the United Kingdom.

Revenue

Revenue	12 Months Ended
	Jan. 31, 2019
Revenue [abstract]
Revenue	Revenue Year ended January 31, 2019 Year ended January 31, 2018 Year ended January 31, 2017 (Adjusted*) £000 £000 £000 Analysis of revenue by category: Licensing agreements 42,766 12,050 2,304 Research collaboration agreement 246 310 — 43,012 12,360 2,304 Revenue recognized in the year consists of amounts received from the license and collaboration agreement with Sarepta Therapeutics, Inc., the license and commercialization agreement with Eurofarma Laboratórios S.A., and amounts received from a research collaboration agreement with F. Hoffmann-La Roche Ltd, which ended in February 2018. See Note 19 ‘ Deferred revenue and income ’ for details of amounts deferred in the Consolidated Statement of Financial Position. Year ended January 31, 2019 Year ended January 31, 2018 Year ended January 31, 2017 (Adjusted*) £000 £000 £000 Analysis of revenue by geography: United States 42,267 12,008 2,304 Latin America 499 42 — Europe 246 310 — 43,012 12,360 2,304 The analysis of revenue by geography has been identified on the basis of the customer’s geographical location. * See Note 3 - ‘ Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers. ’ 5 . Revenue (continued) Sarepta Therapeutics, Inc. On October 4, 2016, Summit announced its entry into an exclusive license and collaboration agreement with Sarepta Therapeutics, Inc. (‘Sarepta’), pursuant to which Summit granted Sarepta the exclusive right to commercialize products in the Group’s utrophin modulator pipeline in the European Union, Switzerland, Norway, Iceland, Turkey and the Commonwealth of Independent States (the 'Sarepta Agreement'). Such products included the Group’s former lead product candidate, ezutromid, and its pipeline of second generation and future generation small molecule utrophin modulators for the treatment of Duchenne muscular dystrophy. The Group also granted Sarepta an option to expand the licensed territory to include specified countries in Central and South America. The Group would retain commercialization rights in the rest of the world. Under the Sarepta Agreement, the Group received from Sarepta an upfront payment of $40.0 million ( £32.8 million ), in October 2016, and a development milestone payment of $22.0 million ( £17.2 million ), in May 2017, which was payable after the first dosing of the last patient in PhaseOut DMD, its Phase 2 clinical trial of ezutromid. The terms of the contract were assessed under IFRS 15 Revenue from contracts with customers , and the upfront payment, first development milestone payment and relevant development cost share income are included in the transaction price which was reported as deferred revenue in the Consolidated Statement of Financial Position and recognized as revenue over the development period. In June 2018, the Group announced the discontinuation of the development of ezutromid after PhaseOut DMD did not meet its primary or secondary endpoints. As a result, the Group has updated the development period over which the revenues are recognized, as described in Note 3 ' Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers .' The development period was deemed to have concluded in June 2018 in line with when development of ezutromid was discontinued. This resulted in all revenues relating to the Sarepta Agreement that were previously deferred in the Statement of Financial Position being released in full to the Statement of Comprehensive Income. As part of the Sarepta Agreement, the Group agreed to collaborate with Sarepta on the research and development of the licensed products pursuant to a joint development plan through a joint steering committee comprised of an equal number of representatives from each party. The Group had been solely responsible for all research and development costs for the licensed products until December 31, 2017. From January 1, 2018, the Group was responsible for 55% of the budgeted research and development costs related to the licensed products in the licensed territory, and Sarepta was responsible for 45% of such costs. Any costs in excess of 110% of the budgeted amount are borne by the party that incurred such costs. This development cost share income is recognized as part of licensing agreements revenue as the Group is acting as a principal in the scope of the research and development activities of the agreement. The Group continues to receive cost share income for both wind-down activities in relation to the ezutromid clinical trial and next and future generation utrophin modulation development activities. Such income is recognized as revenue using an input method based on costs incurred over the duration of the contract. Eurofarma Laboratórios S.A. On December 21, 2017, Summit announced it had entered into an exclusive license and commercialization agreement with Eurofarma Laboratórios S.A. ('Eurofarma'), pursuant to which the Group granted Eurofarma the exclusive right to commercialize ridinilazole in specified countries in South America, Central America and the Caribbean (the 'Eurofarma Agreement'). The Group has retained commercialization rights in the rest of the world. Under the terms of the Eurofarma Agreement, the Group received an upfront payment of $2.5 million ( £1.9 million ) from Eurofarma. The terms of the contract have been assessed, and the Group believes the development services to be indistinguishable from the license and as a result the upfront payment was initially reported as deferred revenue in the Consolidated Statement of Financial Position and is being recognized as revenue over the development period. Accordingly, £0.5 million of revenue will be released during each subsequent financial year until all amounts have been realized in the Consolidated Statement of Comprehensive Income. In addition, the Group will be entitled to receive an additional $3.75 million in development milestones upon the achievement of staged patient enrollment targets in the licensed territory in one of the Group's two planned Phase 3 clinical trials of ridinilazole. The Group is eligible to receive up to $21.4 million in development, commercial and sales milestones when cumulative net sales equal or exceed $100.0 million in the Eurofarma licensed territory. Each subsequent achievement of an additional $100.0 million in cumulative net sales will result in the Group receiving additional milestone payments, which, when combined with anticipated product supply transfer payments from Eurofarma paid to the Group in connection with a commercial supply agreement to be entered into between the two parties, will provide payments estimated to range from a mid- to high-teens percentage of cumulative net sales in the Eurofarma licensed territory. The Group estimates such product supply transfer payments from Eurofarma will range from a high single-digit to low double-digit percentage of cumulative net sales in the licensed territory.

Other operating income (Notes)

Other operating income (Notes)	12 Months Ended
	Jan. 31, 2019
Analysis of income and expense [abstract]
Other operating income	Other operating income Year ended January 31, 2019 Year ended January 31, 2018 Year ended January 31, 2017 £000 £000 £000 Analysis of other operating income by category: Income recognized in respect of BARDA 13,091 1,772 — Grant income 1,187 13 56 Income on remeasurement or derecognition of financial liabilities on funding arrangements (Note 21) 539 908 — Income recognized in respect of the Wellcome Trust — — 13 Research and development credit 333 23 3 Other income 6 9 — 15,156 2,725 72 BARDA In September 2017, the Group was awarded a funding contract worth up to $62 million by the Biomedical Advanced Research and Development Authority ('BARDA'), an agency of the U.S. government's Department of Health and Human Services' Office of the Assistant Secretary for Preparedness and Response. The BARDA contract provides for a cost-sharing arrangement under which BARDA funds a specified portion of estimated costs for specified activities related to the continued clinical and regulatory development of ridinilazole for the treatment of CDI. Under the terms of the contract, the Group was initially eligible to receive $32 million from BARDA to fund, in part, obtaining regulatory approval for and commencing enrollment and dosing into the Group's two Phase 3 clinical trials of ridinilazole. In August 2018, the Group was awarded an additional $12 million upon exercise by BARDA of the first option work segment under the contract, which brought the total committed BARDA funding to $44 million . In addition, the Group is eligible for additional funding under the contract pursuant to two further independent option work segments, which may be exercised by BARDA in its sole discretion upon the achievement of certain development and other milestones for ridinilazole. If BARDA exercises its remaining option work segments in full, the total funding under the contract would increase up to $62 million . Grant income includes income from funding arrangements with CARB-X and Innovate UK grants for the Group's antibiotic pipeline research and development activities. CARB-X In July 2018, the Group was granted a sub-award of up to $4.5 million from the Trustees of Boston University under the Combating Antibiotic Resistant Bacteria Biopharmaceutical Accelerator program, or CARB-X. Under the CARB-X award, the Group received an initial $2.0 million in funding from CARB-X in July 2018 that, in part, helped fund the selection of a preclinical candidate from the Group's lead gonorrhea series of clinical candidates. The remaining $2.5 million is split into two option segments, which may be exercised by CARB-X upon the achievement of certain development milestones. If exercised in full, this funding could support the development of the selected gonorrhea candidate through the end of a Phase 1 clinical trial. Innovate UK In January 2017, the Group's wholly owned subsidiary, Discuva Limited, was awarded a grant by Innovate UK worth up to £1.1 million . The grant helped to fund a specified portion of eligible costs incurred between January 2017 and December 2018 for activities related to the exploitation of transporters to develop novel antibiotics against Gram-negative bacteria. Loss before income tax Year ended January 31, 2019 Year ended January 31, 2018 Year ended January 31, 2017 £000 £000 £000 Research and development Employee benefit expense 6,264 5,616 4,218 Share-based payment expense 1,091 327 374 Program related costs 29,868 21,810 13,605 Amortization of intangible assets 829 105 10 Other research and development costs 1,122 1,112 745 39,174 28,970 18,952 General and administration Employee benefit expense 3,238 2,870 2,480 Share-based payment expense 3,652 1,280 1,005 Foreign exchange (gain) / loss (491 ) 1,986 533 Depreciation of property, plant and equipment 309 141 48 Loss on disposal of assets 43 40 — Other general and administration costs 4,818 5,613 4,211 Loss on contingent consideration 754 — — Royalty expense 19 69 — 12,342 11,999 8,277

Directors and employees

Directors and employees	12 Months Ended
	Jan. 31, 2019
Disclosure Directors And Employees [Abstract]
Directors and employees	Directors and employees The average monthly number of employees of the Group, including Executive Directors, during the year was: Year ended January 31, 2019 Year ended January 31, 2018 Year ended January 31, 2017 Technical, research and development 45 34 23 Corporate and administration 29 26 21 74 60 44 The average number of employees reflects an increase in the Group's workforce during the second half of the year ended January 31, 2018 , and the first half of the year ended January 31, 2019 , to support Phase 3 preparatory activities for ridinilazole and the clinical and regulatory development of ezutromid. The number of employees as at January 31, 2019 , was 61 ( January 31, 2018 : 76 ). This decrease reflects the implementation of cost-cutting measures following the decision to discontinue ezutromid development in June 2018. Their aggregate remuneration comprised: Year ended January 31, 2019 Year ended January 31, 2018 Year ended January 31, 2017 £000 £000 £000 Wages and salaries 8,268 7,493 5,932 Social security costs 844 643 434 Other pension costs 390 350 332 Share-based payment 4,743 1,607 1,379 14,245 10,093 8,077 Included within wages and salaries are termination benefits of £0.2 million (2018: £ nil ). Key management of the Group are members of the Executive Management Team. Excluding the Chief Commercial Officer, who joined the Executive Management Team in February 2019, the aggregate amounts of key management compensation are set out below: Year ended January 31, 2019 Year ended January 31, 2018 Year ended January 31, 2017 £000 £000 £000 Short-term employee benefits Wages and salaries 1,406 1,520 1,252 Social security costs 168 162 98 1,574 1,682 1,350 Post-employment benefits Amounts paid in lieu of employer pension contributions 43 32 17 Other pension costs 11 14 11 54 46 28 Share-based payment 3,177 705 327 Total remuneration 4,805 2,433 1,705

Loss before income tax

Loss before income tax	12 Months Ended
	Jan. 31, 2019
Analysis of income and expense [abstract]
Loss before income tax	Other operating income Year ended January 31, 2019 Year ended January 31, 2018 Year ended January 31, 2017 £000 £000 £000 Analysis of other operating income by category: Income recognized in respect of BARDA 13,091 1,772 — Grant income 1,187 13 56 Income on remeasurement or derecognition of financial liabilities on funding arrangements (Note 21) 539 908 — Income recognized in respect of the Wellcome Trust — — 13 Research and development credit 333 23 3 Other income 6 9 — 15,156 2,725 72 BARDA In September 2017, the Group was awarded a funding contract worth up to $62 million by the Biomedical Advanced Research and Development Authority ('BARDA'), an agency of the U.S. government's Department of Health and Human Services' Office of the Assistant Secretary for Preparedness and Response. The BARDA contract provides for a cost-sharing arrangement under which BARDA funds a specified portion of estimated costs for specified activities related to the continued clinical and regulatory development of ridinilazole for the treatment of CDI. Under the terms of the contract, the Group was initially eligible to receive $32 million from BARDA to fund, in part, obtaining regulatory approval for and commencing enrollment and dosing into the Group's two Phase 3 clinical trials of ridinilazole. In August 2018, the Group was awarded an additional $12 million upon exercise by BARDA of the first option work segment under the contract, which brought the total committed BARDA funding to $44 million . In addition, the Group is eligible for additional funding under the contract pursuant to two further independent option work segments, which may be exercised by BARDA in its sole discretion upon the achievement of certain development and other milestones for ridinilazole. If BARDA exercises its remaining option work segments in full, the total funding under the contract would increase up to $62 million . Grant income includes income from funding arrangements with CARB-X and Innovate UK grants for the Group's antibiotic pipeline research and development activities. CARB-X In July 2018, the Group was granted a sub-award of up to $4.5 million from the Trustees of Boston University under the Combating Antibiotic Resistant Bacteria Biopharmaceutical Accelerator program, or CARB-X. Under the CARB-X award, the Group received an initial $2.0 million in funding from CARB-X in July 2018 that, in part, helped fund the selection of a preclinical candidate from the Group's lead gonorrhea series of clinical candidates. The remaining $2.5 million is split into two option segments, which may be exercised by CARB-X upon the achievement of certain development milestones. If exercised in full, this funding could support the development of the selected gonorrhea candidate through the end of a Phase 1 clinical trial. Innovate UK In January 2017, the Group's wholly owned subsidiary, Discuva Limited, was awarded a grant by Innovate UK worth up to £1.1 million . The grant helped to fund a specified portion of eligible costs incurred between January 2017 and December 2018 for activities related to the exploitation of transporters to develop novel antibiotics against Gram-negative bacteria. Loss before income tax Year ended January 31, 2019 Year ended January 31, 2018 Year ended January 31, 2017 £000 £000 £000 Research and development Employee benefit expense 6,264 5,616 4,218 Share-based payment expense 1,091 327 374 Program related costs 29,868 21,810 13,605 Amortization of intangible assets 829 105 10 Other research and development costs 1,122 1,112 745 39,174 28,970 18,952 General and administration Employee benefit expense 3,238 2,870 2,480 Share-based payment expense 3,652 1,280 1,005 Foreign exchange (gain) / loss (491 ) 1,986 533 Depreciation of property, plant and equipment 309 141 48 Loss on disposal of assets 43 40 — Other general and administration costs 4,818 5,613 4,211 Loss on contingent consideration 754 — — Royalty expense 19 69 — 12,342 11,999 8,277

Impairment of goodwill and inta

Impairment of goodwill and intangible assets	12 Months Ended
	Jan. 31, 2019
Disclosure of detailed information about intangible assets [abstract]
Impairment of goodwill and intangible assets	Impairment of goodwill and intangible assets As a result of the Group's decision in June 2018 to discontinue development of ezutromid, management concluded that this was an indication of impairment and hence reviewed the intangible asset and goodwill associated with the acquisition of MuOx Limited which related to the utrophin program acquired. Based on this review, an impairment charge of £4.0 million was recognized, representing the full aggregate carrying value of the intangible asset of £3.3 million and goodwill of £0.7 million . See Note 15 ' Intangible assets ' for details of the valuation model and assumptions used as part of the review.

Auditors_ remuneration

Auditors’ remuneration	12 Months Ended
	Jan. 31, 2019
Analysis of income and expense [abstract]
Auditors’ remuneration	Auditors’ remuneration Services provided by the Group’s auditors During the year, the Group obtained the following services from the Group’s auditors at the cost detailed below: Year ended January 31, 2019 Year ended January 31, 2018 Year ended January 31, 2017 £000 £000 £000 Fees payable to the auditors and its associates for the audit of the Company and Consolidated Financial Statements 160 132 110 Fees payable to the auditors and its associates for other services: - Audit of the Company’s subsidiaries (1) 119 209 120 - Audit-related assurance services — — 3 - Other assurance services (2) 115 118 163 - Tax compliance and advisory services 25 23 62 Total fees payable 419 482 458 (1) For the year ended January 31, 2018, fees payable for the Consolidated Financial Statements and fees payable for the Company's subsidiaries include audit services relating to the initial audit and business combination accounting for Discuva Limited. These were non-recurring fees. (2) For the year ended January 31, 2019, other assurance services includes reporting in connection with the Company’s registration statement on Form F-3 that was filed with the SEC on May 15, 2018. For the year ended January 31, 2018, other assurance services includes reporting in connection with the Company's underwritten public offering completed on September 18, 2017. These amounts were recognized directly in share premium. For the year ended January 31, 2017, other assurance services includes reporting in connection with the Company’s registration statement on Form F-3 that was originally filed with the SEC on May 12, 2016.

Finance income and costs

Finance income and costs	12 Months Ended
	Jan. 31, 2019
Disclosure of finance income and costs [Abstract]
Finance income and costs	Finance income and costs Note Year ended January 31, 2019 Year ended January 31, 2018 Year ended January 31, 2017 £000 £000 £000 Finance income Remeasurement or derecognition of financial liabilities on funding arrangements 21 2,784 3,085 — Interest income on deposits 4 11 8 Finance income 2,788 3,096 8 Finance costs Unwinding of discount factor 21 (424 ) (754 ) (862 ) Remeasurement of financial liabilities on funding arrangements 21 — (410 ) — Finance costs (424 ) (1,164 ) (862 )

Income tax

Income tax	12 Months Ended
	Jan. 31, 2019
Disclosure Of Income Tax [Abstract]
Income tax	Income tax Year ended January 31, 2019 Year ended January 31, 2018 Year ended January 31, 2017 £000 £000 £000 Analysis of credit in the period Current tax : Current tax income 1,286 3,767 4,245 Adjustments in respect of prior years 506 (5 ) (9 ) Total current tax 1,792 3,762 4,236 Total deferred tax 704 — 100 Total tax 2,496 3,762 4,336 The difference between the total tax shown above and the amount calculated by applying the standard rate of U.K. corporation tax to the loss before tax is as follows: Year ended January 31, 2019 Year ended January 31, 2018 Year ended January 31, 2017 (Adjusted*) £000 £000 £000 Profit / (loss) before tax 5,031 (23,952 ) (25,707 ) Profit / (loss) multiplied by the standard rate of corporation tax in the United Kingdom (Current tax) 19% (2018: 19.17%) 956 (4,592 ) (5,141 ) Adjustment for IFRS 15 restatement (2,481 ) 2,504 — Change in unrecognized tax losses 820 751 2,169 Non-deductible expenses 1,797 402 331 Tax relief for qualifying research and development expenditure (2,656 ) (3,043 ) (1,699 ) Prior year adjustments (506 ) 5 9 Share options exercised (15 ) (40 ) (84 ) Overseas profits taxed at different rates 292 251 179 Change in rate of deferred tax (703 ) — (100 ) Total tax (2,496 ) (3,762 ) (4,336 ) * See Note 3 - ‘ Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers. ’ There are no current tax liabilities as at January 31, 2019 ( 2018 : nil; 2017 : nil). Tax relief for qualifying research and development expenditure relates to U.K. research and development tax credits claimed through the small or medium-sized enterprise scheme ('SME') under the Finance Act 2015. 12 . Income tax (continued) The Finance (No 2) Act 2015, which provides for reductions in the main rate of corporation tax from 20% to 19% effective from April 1, 2017, and to 18% effective from April 1, 2020, was substantively enacted on October 26, 2015. Subsequently, the Finance Act 2016, which provides for a further reduction in the main rate of corporation tax to 17% effective from April 1, 2020, was substantively enacted on September 6, 2016. These rate reductions have been reflected in the calculation of deferred tax at the year end date. The closing deferred tax liability at January 31, 2019 , has been calculated at 17% reflecting the tax rate at which the deferred tax liability is expected to be reversed in future periods. Unrecognized deferred tax has been calculated at 17% reflecting the latest enacted rate. In respect of unrecognized deferred tax on losses, the new loss restriction rules effective from April 1, 2017, limit the amount of brought forward losses available to use against future taxable profits on a year by year basis to the extent that taxable profits exceed £5.0 million in each year. However, the losses will not lapse and therefore the full amount will be relieved over time provided there are sufficient profits against which the losses can be utilized. Please see Note 24 ‘ Deferred tax liability ’ for information on the unrecognized tax losses carried forward.

Earnings _ (loss) per share

Earnings / (loss) per share	12 Months Ended
	Jan. 31, 2019
Earnings per share [abstract]
Earnings / (loss) per share	Earnings / (loss) per share The calculation of earnings / (loss) per share is based on the following data: Year ended January 31, 2019 Year ended January 31, 2018 Year ended January 31, 2017 (Adjusted*) 000s 000s 000s Profit / (loss) for the year £ 7,527 £ (20,190 ) £ (21,371 ) Weighted average number of ordinary shares for basic earnings / (loss) earnings per share 85,702 65,434 61,549 Effect of dilutive potential ordinary shares (share options and warrants) 442 — — Weighted average number of ordinary shares for diluted earnings per share 86,144 65,434 61,549 Basic earnings / (loss) per ordinary share from operations £ 0.09 (0.31 ) (0.35 ) Diluted earnings / (loss) per ordinary share from operations £ 0.09 (0.31 ) (0.35 ) * See Note 3 - ‘ Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers. ’ Basic earnings / (loss) per ordinary share has been calculated by dividing the profit / (loss) for the year ended January 31, 2019 , by the weighted average number of shares in issue during the year ended January 31, 2019 . Diluted earnings per ordinary share has been calculated by adjusting the weighted average number of ordinary shares outstanding to assume conversion of all potentially dilutive ordinary shares. Potentially dilutive ordinary shares are the number of shares that could have been acquired at fair value based on the monetary value of the subscription rights attached to share options in-the-money compared with the number of shares that would have been issued assuming the exercise of share options in-the-money. At January 31, 2019 , total outstanding share options were 9,168,396 and total outstanding restricted stock units (‘RSUs’) were 814,256 . Of these equity instruments, 8,094,227 were not included in the calculation of potentially dilutive ordinary shares for the year ended January 31, 2019 , as they are not dilutive. IAS 33 ‘ Earnings per Share ’ requires the presentation of diluted earnings per share where a company could be called upon to issue shares that would decrease net profit or loss per share. As the Group reported net losses for the year ended January 31, 2018 , the weighted average number of ordinary shares outstanding used to calculate the diluted earnings / (loss) per ordinary share is the same as that used to calculate the basic earnings / (loss) per ordinary share, as the exercise of share options would have the effect of reducing loss per ordinary share which is not dilutive.

Goodwill

Goodwill	12 Months Ended
	Jan. 31, 2019
Disclosure of detailed information about intangible assets [abstract]
Goodwill	Goodwill Discuva Limited £000 MuOx Limited £000 Total £000 Cost At February 1, 2018 1,814 664 2,478 At January 31, 2019 1,814 664 2,478 Accumulated impairment At February 1, 2018 — — — Impairment — (664 ) (664 ) At January 31, 2019 — (664 ) (664 ) Net book amount At February 1, 2018 1,814 664 2,478 At January 31, 2019 1,814 — 1,814 Discuva Limited £000 MuOx Limited £000 Total £000 Cost At February 1, 2017 — 664 664 Additions 1,814 — 1,814 At January 31, 2018 1,814 664 2,478 Accumulated impairment At February 1, 2017 — — — At January 31, 2018 — — — Net book amount At February 1, 2017 — 664 664 At January 31, 2018 1,814 664 2,478 Goodwill represents the difference between the fair value of the identifiable assets acquired and liabilities assumed and the amount paid in consideration . In accordance with IAS 36 ‘ Impairment of Assets ’, the remaining goodwill has been reviewed for impairment and no further provision is considered necessary. The impairment reviews of goodwill undertaken during the financial year and at the year end are included as part of the intangible assets impairment review in Note 15 ‘ Intangible assets .’ Goodwill relating to MuOx Limited formed part of the same cash-generating unit as the utrophin program acquired. Goodwill relating to Discuva Limited forms part of the same cash-generating unit as the Discuva Platform acquired. On December 23, 2017, the Group acquired 100% of the share capital of Discuva Limited a privately held U.K.-based company, resulting in the recognition of £1.8 million of goodwill. Goodwill recognized in respect of Discuva Limited is attributable to the synergies expected with the Group's ongoing business as a result of the acquisition and the existing Discuva Limited workforce (which cannot be separately valued under IFRS accounting standards).

Intangible assets

Intangible assets	12 Months Ended
	Jan. 31, 2019
Disclosure of detailed information about intangible assets [abstract]
Intangible assets	Intangible assets Utrophin Discuva Platform acquired Option over non-financial assets Other Total Cost At February 1, 2018 3,321 10,670 668 265 14,924 Additions — — — 6 6 Disposals — — — (49 ) (49 ) At January 31, 2019 3,321 10,670 668 222 14,881 Accumulated amortization At February 1, 2018 — (79 ) (4 ) (56 ) (139 ) Charge for the year — (739 ) (45 ) (45 ) (829 ) Impairment (3,321 ) — — — (3,321 ) Disposals — — — 12 12 At January 31, 2019 (3,321 ) (818 ) (49 ) (89 ) (4,277 ) Net book amount At February 1, 2018 3,321 10,591 664 209 14,785 At January 31, 2019 — 9,852 619 133 10,604 Iminosugar Utrophin Discuva Platform acquired Option over non-financial assets Other Total Cost At February 1, 2017 1,380 3,321 — — 204 4,905 Acquisition of subsidiary — — 10,670 668 — 11,338 Additions — — — — 119 119 Disposals (1,380 ) — — — (58 ) (1,438 ) At January 31, 2018 — 3,321 10,670 668 265 14,924 Accumulated amortization At February 1, 2017 (1,380 ) — — — (55 ) (1,435 ) Charge for the year — — (79 ) (4 ) (23 ) (106 ) Disposals 1,380 — — — 22 1,402 At January 31, 2018 — — (79 ) (4 ) (56 ) (139 ) Net book amount At February 1, 2017 — 3,321 — — 149 3,470 At January 31, 2018 — 3,321 10,591 664 209 14,785 Amortization of intangible assets is included in the line ‘Research and development’ shown on the face of the Consolidated Statement of Comprehensive Income. In accordance with IAS 36, intangible assets not subject to amortization and the associated goodwill are reviewed for impairment annually or whenever there is an indication that the intangible asset may be impaired. The recoverable amount of an asset or a cash-generating unit is defined as the higher of its fair value and its value in use. MuOx Limited goodwill and utrophin program acquired cash-generating unit As discussed in Note 9 ' Impairment of goodwill and intangible assets ', as a result of the Group's decision in June 2018 to discontinue development of ezutromid, an impairment charge of £4.0 million was recognized, representing the full aggregate carrying value of the intangible asset of £3.3 million and goodwill of £0.7 million . 15 . Intangible assets (continued) Discuva Limited goodwill and Discuva Platform acquired cash-generating unit The Discuva Platform acquired as part of the acquisition of Discuva Limited and the associated goodwill have been reviewed for impairment using a milestone analysis approach, since reliable estimated future cash flows cannot yet be formed to determine the value in use. The milestone analysis approach assesses whether the fair value of these assets, determined upon acquisition of Discuva Limited in December 2017, still remain appropriate. Based on this assessment, the Directors believe that the carrying value of the intangible asset and associated goodwill are supported by the underlying asset. The key milestone events that were considered as part of the impairment assessment are as follows: • research and development milestones achieved; and • external transactions achieved. The key sensitivity is our ability to meet ongoing milestone events, if these milestone events are not achieved as expected then the related intangible asset would likely be fully impaired.

Property, plant and equipment

Property, plant and equipment	12 Months Ended
	Jan. 31, 2019
Disclosure of detailed information about property, plant and equipment [abstract]
Property, plant and equipment	over their estimated useful lives as follows: Property, plant and equipment Cost Leasehold improvements £000 Laboratory equipment £000 Office and IT equipment £000 Total £000 At February 1, 2018 340 299 486 1,125 Additions — 62 57 119 Disposals — (22 ) (52 ) (74 ) Revaluation — — 5 5 At January 31, 2019 340 339 496 1,175 Accumulated depreciation At February 1, 2018 (31 ) (36 ) (249 ) (316 ) Charge for the year (34 ) (156 ) (119 ) (309 ) Disposals — 21 47 68 Revaluation — — (2 ) (2 ) At January 31, 2019 (65 ) (171 ) (323 ) (559 ) Net book value At February 1, 2018 309 263 237 809 At January 31, 2019 275 168 173 616 Cost Leasehold improvements £000 Laboratory equipment £000 Office and IT equipment £000 Total £000 At February 1, 2017 9 19 284 312 Acquisition of subsidiary — 280 49 329 Additions 340 — 173 513 Disposals (9 ) — (14 ) (23 ) At January 31, 2018 340 299 486 1,125 Accumulated depreciation At February 1, 2017 (9 ) (17 ) (170 ) (196 ) Charge for the year (31 ) (19 ) (90 ) (140 ) Disposals 9 — 10 19 At January 31, 2018 (31 ) (36 ) (249 ) (316 ) Net book value At February 1, 2017 — 2 114 116 At January 31, 2018 309 263 237 809

Trade and other receivables

Trade and other receivables	12 Months Ended
	Jan. 31, 2019
Trade and other receivables [abstract]
Trade and other receivables	Trade and other receivables January 31, 2019 January 31, 2018 £000 £000 Trade receivables 1,656 — Other receivables 3,847 3,600 Prepayments 7,433 6,498 Accrued income 611 1,036 13,547 11,134 Trade receivables consist of amounts outstanding from Sarepta at January 31, 2019 . Included within prepayments is £6.8 million of prepayments relating to research and development expenditure. These amounts are determined based on the estimated costs to complete each study or activity, the estimation of the current stage of completion and the invoices received. The key sensitivity is the estimated current stage of completion of each study or activity. If the estimated stage of completion increased by 5% then the aggregate increase in accruals and decrease in prepayments would result in an overall increase in total research and development expenses of £1.0 million . If the estimated stage of completion decreased by 5% then the aggregate decrease in accruals and increase in prepayments would result in an overall decrease in total research and development expenses of £1.2 million .

Trade and other payables

Trade and other payables	12 Months Ended
	Jan. 31, 2019
Trade and other payables [abstract]
Trade and other payables	Trade and other payables January 31, 2019 January 31, 2018 £000 £000 Trade payables 4,422 4,414 Other taxes and social security 190 164 Accruals 4,095 4,078 Other creditors 158 276 8,865 8,932 Included within accruals is £1.9 million of accruals relating to research and development expenditure. These amounts are determined based on the estimated costs to complete each study or activity, the estimation of the current stage of completion and the invoices received. See Note 17 ' Trade and other receivables ' for information regarding the sensitivity of this estimate.

Deferred revenue and income

Deferred revenue and income	12 Months Ended
	Jan. 31, 2019
Accruals and deferred income [abstract]
Deferred revenue and income	Deferred revenue and income January 31, 2019 January 31, 2018 (Adjusted*) £000 £000 Due within one year Deferred revenue 499 11,478 Deferred other operating income 2,875 2,356 3,374 13,834 Due more than one year Deferred revenue 831 27,270 831 27,270 Total deferred revenue 1,330 38,748 Total deferred other operating income 2,875 2,356 * See Note 3 - ‘ Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers. ’ 19 . Deferred revenue and income (continued) The Group adopted IFRS 15 effective February 1, 2018, as required. For details on the performance obligations identified and judgments exercised by management in the application of IFRS 15 see Note 3 ‘ Changes to accounting policies -Adoption of IFRS 15 Revenue from contracts with customers.' Revenues of £37.4 million included in deferred revenue as at January 31, 2018 (adjusted), were recognized during the year ended January 31, 2019 . All revenues recognized during the year ended January 31, 2018 , were included in deferred revenue as at January 31, 2017 . See Note 5 ' Revenue ' for details on the Group's revenue agreements and revenue recognition.

Contingent consideration

Contingent consideration	12 Months Ended
	Jan. 31, 2019
Disclosure of contingent liabilities [abstract]
Contingent consideration	Contingent consideration During the financial year, the Group reassessed the contingent consideration in line with the anticipated settlement of consideration liabilities relating to the acquisition of Discuva Limited ('Discuva') in December 2017. The Group estimated the total expected additional cash outflows to be £0.8 million , w hich is based on the terms of the share purchase agreement. The additional expected payment is primarily due to research and development tax credits received and receivable by Discuva in respect of financial years prior to the Group's acquisition, of which the sellers are due a specified portion of these amounts. During the year ended January 31, 2019 , a payment of £0.2 million was made for the research and development tax credits received, leaving an estimated contingent consideration liability of £0.6 million . The table below describes the value of the assumed contingent liabilities as at January 31, 2019 , of £1.7 million compared to what the total value would be following the presented variations to the underlying assumptions in the model: January 31, 2019 £000s Estimated assumed contingent liabilities 1,658 1% lower discount rate 1,770 1% higher discount rate 1,560 10% lower probability of success 1,366 10% higher probability of success 1,927

Financial liabilities on fundin

Financial liabilities on funding arrangements	12 Months Ended
	Jan. 31, 2019
Financial Liabilities At Amortised Cost [Abstract]
Financial liabilities on funding arrangements	Financial liabilities on funding arrangements The Group entered into charitable funding arrangements with the Wellcome Trust and the U.S. not for profit organizations, the Muscular Dystrophy Association (‘MDA’) and Duchenne Partners Fund (‘DPF’). In exchange for the funding provided, these arrangements required the Group to pay royalties on potential future revenues generated from the CDI and DMD programs respectively or transfer the rights over unexploited intellectual property. Discount factors used in the financial liability models were calculated using appropriate measures and rates which could have been obtained in the period that the funding agreements were entered into and are in the range of 16% to 18% for the financial liabilities of funding arrangements previously recognized. Because of the Group's decision in June 2018 to discontinue the development of ezutromid, the financial liabilities attributable to the charitable funding arrangements with MDA and DPF were remeasured during the year ended January 31, 2019 , as future royalties on revenues generated from the DMD program are no longer anticipated. This remeasurement resulted in a credit to the Statement of Comprehensive Income. The portion of the credit presented as other operating income during the year ended January 31, 2019 , represents the component of the funding received from MDA and DPF not previously credited to the Statement of Comprehensive Income upon initial recognition of the financial liability. The portion of the credit presented as finance income during the year ended January 31, 2019 , relates to previous remeasurements and discounting associated with the financial liability which were previously recognized as finance costs. In October 2017, the Group and the Wellcome Trust entered into an equity and revenue sharing agreement under which the Wellcome Trust agreed to terminate all of its rights pertaining to the exploitation of intellectual property related to the CDI program meaning the arrangement no longer met the definition of a financial liability under IFRS and the financial liability was derecognized. 21 . Financial liabilities on funding arrangements (continued) The value of the estimated financial liabilities for funding arrangements as of January 31, 2019 , amounted to £ nil ( January 31, 2018 : £3.1 million ). January 31, 2019 January 31, 2018 £000 £000 At February 1 3,090 5,919 Unwinding of discount factor 233 754 Derecognition of financial liabilities – finance income — (3,085 ) Remeasurement of financial liabilities on funding arrangements - (2,784 ) 410 Net finance income on funding arrangements accounting for as financial liabilities (2,551 ) (1,921 ) Remeasurement or derecognition of financial liabilities – other operating income (539 ) (908 ) At January 31 — 3,090 As the Group is discontinuing the development of ezutromid, there are no sensitivities disclosed in relation to the charitable funding arrangements with MDA and DPF, since there are no reasonably possible changes in assumptions that would result in a different value of the liability as at January 31, 2019 .

Financial instruments

Financial instruments	12 Months Ended
	Jan. 31, 2019
Financial Instruments [Abstract]
Financial instruments	Financial instruments January 31, 2019 January 31, 2018 Note £000 £000 Financial assets at amortized cost Trade and other receivables (1) 17 5,503 3,600 Cash and cash equivalents 26,858 20,102 32,361 23,702 Financial liabilities measured at amortized cost Trade and other payables 18 8,865 8,932 Financial liabilities on funding arrangements 21 — 3,090 8,865 12,022 Financial liabilities measured at fair value through profit and loss Contingent consideration 20 629 — (1) Prepayments and accrued income have been excluded as they are not considered to be a financial instrument. The Group’s activities expose it to a variety of financial risks: foreign currency risk; interest rate risk; credit risk; and liquidity risk. The Group’s principal financial instrument comprises cash and cash equivalents, and this is used to finance the Group’s operations. Other financial instruments include trade and other receivables and trade and other payables that arise directly from its operations. The category of other receivables all mature within one year . The Group has compared fair value to book value for each class of financial asset and liability and no differences were identified. The Group has a policy, which has been consistently followed, of not trading in financial instruments. 22 . Financial instruments (continued) Foreign currency risk Foreign currency risk refers to the risk that the value of a financial commitment or recognized asset or liability will fluctuate due to changes in foreign currency rates. The Group’s net income and financial position, as expressed in Pounds Sterling, are exposed to movements in foreign exchange rates against the U.S. Dollar and the Euro. The main trading currencies of the Group are Pounds Sterling, the U.S. Dollar, and the Euro. The Group is exposed to foreign currency risk as a result of trading transactions, including the receipt of potential payments related to the Group’s agreements with Sarepta, Eurofarma, BARDA and CARB-X, capital raises in the U.S. and the translation of foreign bank accounts. The exposure to foreign exchange is monitored by the Group’s finance function. Exposures are generally managed through natural hedging via the currency denomination of cash balances and any realized impact currently is not material to the Group. January 31, 2019 January 31, 2018 £000 £000 Cash at bank and in hand Pounds Sterling 3,363 5,535 U.S. Dollar 23,495 14,567 26,858 20,102 Interest rate risk One of the risks arising from the Group’s financial instruments is interest rate risk. The Group holds no derivative instruments to manage interest rate risk; instead the Group placed deposits surplus to short-term working capital requirements with a variety of reputable U.K.-based and U.S.-based banks and building societies. There were no amounts on short term deposits at the year end. These balances are placed at fixed rates of deposit with maturities between one month and three months. The Group’s cash and short-term deposits were as follows: January 31, 2019 January 31, 2018 £000 £000 On current account 26,858 20,102 26,858 20,102 The interest rates for dated deposits were dependent on the rates offered by the Group’s borrowers. The interest rate for short-term deposits is variable dependent on the rates offered by the Group’s banks. During the year to January 31, 2019 , the banking facilities returned an average rate after fees of 0.02% ( 2018 : 0.02% ). The Group’s exposure to interest rate risk is illustrated with regard to the opening and closing cash balances and the difference that an increase or decrease of 1% in interest rates would have made based on the average cash balance of £ 23.5 million ( 2018 : £ 24.1 million ) in the year: Year ended January 31, 2019 (1)% Actual 1% Interest rate — 0.02 1.02 Interest received (£000) — 4 239 Year ended January 31, 2018 (1)% Actual 1% Interest rate — 0.02 1.02 Interest received (£000) — 5 246 Credit risk The credit risk with respect to customers is limited as the Group has only a small number of customers, being Sarepta and Eurofarma. The Group had £1.7 million trade receivables outstanding at January 31, 2019 , from Sarepta. Financial instruments that potentially expose the Group to concentrations of credit risk consist primarily of short-term cash deposits and trade accounts receivable. Cash is held at a variety of financial institutions with strong credit ratings; these cash deposits typically bore minimal credit risk in the year. Cash balances maintained during the year have been principally held with reputable U.K.-based and U.S.-based banks and building societies. The Group does not believe that this constituted a major credit risk. As of January 31, 2019 , and January 31, 2018 , the majority of cash and cash equivalents were placed with HSBC Bank plc. 22 . Financial instruments (continued) Liquidity risk Prudent liquidity risk management implies maintaining sufficient cash and the availability of funding through an adequate amount of committed credit facilities. The Group ordinarily finances its activities through cash generated from operating activities, and private and public offerings of equity securities. The Group's operating cash flows together with available cash and cash equivalents are expected to be sufficient to enable the Group to fund its anticipated needs through January 31, 2020. See Note 1 ‘Going concern’. All of the financial liability categories at each balance sheet date, excluding the financial liabilities on funding arrangements, have maturity dates of less than 12 months from the year end date. Provisions are amounts contingent upon events taking place and the recognition of deferred taxation is dependent upon future profits arising. Capital management The primary aim of the Group’s capital management, defined as its share capital and share premium, is to safeguard the Group’s ability to continue as a going concern, to support its programs and maximize shareholder value. The Group monitors its capital structure and makes adjustments, as and when it is deemed necessary and appropriate to do so, using such methods as the issuing of new ordinary shares. The capital structure of the Group has come entirely from equity issues.

Provisions for other liabilitie

Provisions for other liabilities and charges and contingent liabilities	12 Months Ended
	Jan. 31, 2019
Disclosure of contingent liabilities [abstract]
Provisions for other liabilities and charges and contingent liabilities	Provisions for other liabilities and charges and contingent liabilities Assumed contingent liabilities £000s Dilapidations £000s Royalties £000s Total At February 1, 2018 1,466 150 25 1,641 Additions — — 19 19 Unwinding of the discount factor 191 — — 191 At January 31, 2019 1,657 150 44 1,851 Assumed contingent liabilities £000s Dilapidations £000s Royalties £000s Total At February 1, 2017 — 85 — 85 Additions 1,466 150 25 1,641 Used during the year — (85 ) — (85 ) At January 31, 2018 1,466 150 25 1,641 Assumed contingent liability As part of the acquisition of Discuva Limited ('Discuva') in December 2017, the Group assumed certain contingent liabilities as certain employees, former employees and former directors of Discuva are eligible for payments from Discuva based on specified development and clinical milestones related to proprietary product candidates developed under the Discuva Platform. The timing of these potential payments is uncertain. On the date of acquisition, the fair value of the assumed contingent liability was estimated using the expected value of the payments. The assumed contingent liabilities are subsequently measured at amortized cost using discounted cash flow models which calculate the risk adjusted net present values of estimated potential future cash flows of the payments. The assumed contingent liabilities are remeasured when there is a specific significant event that provides evidence of a significant change in the probability of successful development and clinical milestones being achieved. The models will be updated for changes in the probability of successful development and clinical milestones being achieved and other associated assumptions with the discount factor to remain unchanged within the model. A discount factor of 13% has been used to discount the contingent liabilities back to net present value. This discount factor has been calculated using appropriate measures and rates which could have been obtained in the period that the contingent liabilities were assumed. 23 . Provisions for other liabilities and charges and contingent liabilities (continued) The estimated fair value of the assumed contingent liability as at January 31, 2019 , is £1.7 million ( January 31, 2018 : £1.5 million ). The contingent liability has not been remeasured during the period. The table below describes the value of the assumed contingent liabilities as at January 31, 2019 , of £1.7 million compared to what the total value would be following the presented variations to the underlying assumptions in the model: January 31, 2019 £000s Estimated assumed contingent liabilities 1,658 1% lower discount rate 1,770 1% higher discount rate 1,560 10% lower probability of success 1,366 10% higher probability of success 1,927 Dilapidations Management has made a provision in respect of the dilapidation costs associated with the reinstatement obligations on their current lease based on best estimates. It is management’s intention to utilize the provision at the end of the lease term. Royalties The provision in respect of royalties relates to the amounts due to the Wellcome Trust under the terms of the funding arrangement as described below. The provision has been discounted to take account of the effect of the time value of money, applying a discount rate of 0.8% . Further information on the contingent liabilities included in the Wellcome Trust arrangement are detailed below. In addition to those items provided for above, the Group also has the following contingent liabilities: The School of Pharmacy, University of London The Group has agreed to pay The School of Pharmacy, University of London, a low single-digit share of all revenue, pre and post commercialization, received by the Group in respect of ridinilazole up to a maximum of £ 1.0 million in consideration of their role in the development of the initial compound series from which ridinilazole was later identified. Following the license and commercialization agreement entered into with Eurofarma, an initial payment was made to The School of Pharmacy of £0.04 million . Wellcome Trust Under the terms of the funding arrangement entered into in October 2017, the Wellcome Trust is entitled to a share of the cumulative net revenue that the Group or its affiliates receive from exploiting the exploitation IP or award products. If Summit undertakes the commercialization of ridinilazole, the Wellcome Trust would be eligible to receive a low-single digit percentage share of net revenues. If a third party undertakes the commercialization of ridinilazole, the Wellcome Trust would be eligible to receive a mid-single digit percentage share of net revenues received by Summit from sales by the third party and a milestone payment of a low-single digit percentage of any cumulative pre-commercial payments received by Summit from third-party licensees. In both instances outlined above, the Group would also be obligated to pay the Wellcome Trust a milestone of a specified amount if cumulative net revenue exceeds a specified amount. Following the license and commercialization agreement entered into with Eurofarma, an initial payment became due to the Wellcome Trust upon commercialization of ridinilazole. The payment has been provided for by the Group as at the year end date and has been discounted back to net present value relative to the expected timing of commercialization of ridinilazole.

Deferred tax liability

Deferred tax liability	12 Months Ended
	Jan. 31, 2019
Deferred tax assets and liabilities [abstract]
Deferred tax liability	Deferred tax liability The Group's deferred tax liability includes amounts recognized upon acquisition of Discuva Limited, which took place in the year ended January 31, 2018. During the year ended January 31, 2019, amounts recognized upon acquisition of MuOx Limited of £0.6 million were released to the Statement of Comprehensive Income when the related intangible asset was impaired in full, see Note 9 ' Impairment of goodwill and intangible assets ' for further details. Year ended January 31, 2019 Year ended January 31, 2018 £000 £000 Amounts falling due after more than one year At February 1 2,379 565 Release of temporary difference relating to the intangible asset (704 ) — Acquisition of subsidiary — 1,814 At January 31 1,675 2,379 There is an unrecognized deferred tax asset in relation to the trading losses carried forward of £ 12,400,000 ( 2018 : £ 11,944,000 ), £ 26,000 in relation to provisions ( 2018 : £ 26,000 ) and £ 32,000 ( 2018 : £ 588,000 ) in relation to future exercisable shares. There is a deferred tax liability of £ 43,000 ( 2018 : £ 71,000 ) in respect of accelerated capital allowances, which has been offset against the deferred tax asset in relation to trading losses carried forward. The unrecognized deferred tax asset would be recovered against future company taxable profits. In the opinion of the Directors, there is insufficient evidence that the asset will be recovered, and as such the deferred tax asset has not been recognized in the financial statements.

Share capital

Share capital	12 Months Ended
	Jan. 31, 2019
Disclosure Of Share Capital, Reserves And Other Equity Interest [Abstract]
Share capital	Share capital January 31, 2019 January 31, 2018 £000 £000 Allotted, called up and fully paid 160,389,881 (2018: 73,563,624) Ordinary Shares of 1p each 1,604 736 Changes to the number of ordinary shares in issue have been as follows: Number of shares Total nominal value £000 Total share premium £000 Total consideration £000 At February 1, 2017 61,841,566 618 46,420 47,038 New share capital issued (net of transaction costs) 8,389,250 84 13,419 13,503 Issue of ordinary shares as consideration for a business combination (1) 2,934,272 30 — 30 New share capital issued from exercise of warrants 50,000 1 9 10 Share options exercised 348,536 3 389 392 At January 31, 2018 73,563,624 736 60,237 60,973 At February 1, 2018 73,563,624 736 60,237 60,973 New share capital issued (net of transaction costs) 86,458,333 864 32,471 33,335 Share options exercised 367,924 4 98 102 At January 31, 2019 160,389,881 1,604 92,806 94,410 (1) The difference between the nominal value of the share capital acquired in Discuva Limited and fair value of shares issued in the business combination using the acquisition method of accounting was recognized as part of the Group's merger reserve arising as a result of certain requirements in the United Kingdom. 25 . Share capital (continued) On March 29, 2018, the c ompany completed an equity placing on the AIM market of the London Stock Exchange, issuing 8,333,333 new ordinary shares at a price of 180 pence per share. Total gross proceeds of £15.0 million were raised and directly attributable transaction costs o f £0.9 million were incurred and accounted for as a deduction from equity. On January 9, 2019, the c ompany completed a private placement of 15,625,000 American Depository Shares ('ADS') at a price of $ 1.60 per ADS. Each ADS represents five ordinary shares of one penny nominal value each in the capital of the c ompany, meaning 78,125,000 new ordinary shares were issued. Total gross proceeds of $25.0 million ( £19.6 million ) were raised and directly attributable transaction costs of £0.4 million were incurred. During the year to January 31, 2019 , the following exercises of share options and restricted stock units took place: Date Number of options exercised March 16, 2018 4,216 April 18, 2018 38,850 April 23, 2018 48,981 July 18, 2018 136,991 October 24, 2018 138,886 367,924 The total net proceeds from exercised share options during the year was £ 0.1 million . All new ordinary shares rank pari passu with existing ordinary shares. Following the equity placings and the exercise of the above share options, the number of ordinary shares in issue was 160,389,881 . Dividends No dividends were paid or declared in the year ended January 31, 2019 (year ended January 31, 2018 : £ nil ).

Share option scheme and restric

Share option scheme and restricted stock units	12 Months Ended
	Jan. 31, 2019
Disclosure Of Share-Based Payment Arrangements [Abstract]
Share option scheme and restricted stock units	Share option scheme and restricted stock units At January 31, 2019 , the outstanding share options, which include the share options granted to Directors, are shown below: Date of grant Exercise price (£) Number of shares Date from which exercisable Expiry date Approved EMI scheme April 7, 2011 0.65 5,873 April 8, 2014 April 7, 2021 May 10, 2012 0.60 150,046 May 10, 2014 May 10, 2022 December 24, 2012 0.85 21,500 December 24, 2015 December 24, 2022 January 31, 2013 0.20 72,973 July 31, 2013 January 31, 2023 July 15, 2014 1.26 100,000 July 15, 2016 July 15, 2024 June 23, 2016 1.05 58,564 June 23, 2017 June 23, 2026 408,956 Unapproved scheme December 18, 2013 0.20 76,364 June 18, 2014 December 18, 2023 July 15, 2014 1.26 175,000 July 15, 2016 July 15, 2024 July 15, 2014 0.80 100,000 May 30, 2015 May 30, 2023 January 21, 2015 1.23 75,000 January 21, 2017 January 21, 2025 June 23, 2016 0.01 110,576 July 21, 2016 June 23, 2026 June 23, 2016 1.05 43,740 June 23, 2017 June 23, 2026 June 27, 2017 1.80 5,989 June 27, 2017 June 27, 2027 July 18, 2017 1.83 11,825 June 18, 2018 June 18, 2027 October 24, 2017 1.80 12,264 October 24, 2018 October 24, 2027 April 20, 2018 2.05 9,514 April 23, 2019 April 23, 2028 October 19, 2018 0.30 4,324,198 October 19, 2019 October 19, 2028 October 19, 2018 0.30 3,814,970 October 19, 2021 October 19, 2028 8,759,440 9,168,396 The Group has no legal or constructive obligation to repurchase or settle the options in cash. The movement in the number of share options is set out below: Weighted average exercise price £ Year ended January 31, 2019 Weighted average exercise price £ Year ended January 31, 2018 Outstanding at February 1, 1.43 8,577,236 1.17 7,383,401 Granted during the year 0.76 13,081,048 1.83 2,972,903 Lapsed / surrendered during the year 1.52 (12,397,841 ) 0.99 (1,430,532 ) Exercised during the year 1.08 (92,047 ) 1.13 (348,536 ) Number of options outstanding at January 31, 0.35 9,168,396 1.43 8,577,236 During the year ended January 31, 2019 , the executive director, key management and employees voluntarily surrendered options to subscribe for a total of 7,172,054 ordinary shares. The share-based payment expense for the year ended January 31, 2019 , was £4.7 million ( 2018 : £1.6 million ). This increase is primarily due to the surrender of share options, resulting in an accelerated share-based payment expense of the remaining fair value of those awards. As at January 31, 2019 , 1,029,228 share options were capable of being exercised with a weighted average exercise price per option of 82 pence ( 2018 : 2,042,546 with a weighted average exercise price per option of 100 pence). The options outstanding at January 31, 2019 , had a weighted average exercise price per option of 35 pence ( 2018 : 143 pence), and a weighted average remaining contractual life of 9.2 years ( 2018 : 7.9 years). 26 . Share option scheme and restricted stock units (continued) The fair value per share option award granted and the assumptions used in the calculations are as follows: Date of grant Type of award Number of shares Exercise price (£) Share price at grant date (£) Fair value per option (£) Award life (years) Risk free rate April 07, 2011 EMI 5,873 0.65 0.65 0.47 5.00 2.70 % May 10, 2012 EMI 150,046 0.60 0.52 0.24 5.00 1.00 % December 24, 2012 EMI 21,500 0.85 0.85 0.59 5.00 0.90 % January 31, 2013 EMI 72,973 0.20 0.94 0.74 5.00 1.00 % December 18, 2013 Unapproved 76,364 0.20 1.85 1.65 5.00 1.00 % July 15, 2014 EMI 100,000 1.26 1.26 0.65 3.00 1.30 % July 15, 2014 Unapproved 175,000 1.26 1.26 0.65 3.00 1.30 % July 15, 2014 Unapproved 100,000 0.80 0.81 0.65 1.90 0.50 % January 21, 2015 Unapproved 75,000 1.23 1.22 0.64 3.00 0.60 % June 23, 2016 EMI 58,564 1.05 1.05 0.25 3.00 0.30 % June 23, 2016 Unapproved 110,576 0.01 1.05 1.04 0.50 0.30 % June 23, 2016 Unapproved 43,740 1.05 1.05 0.25 3.00 0.30 % June 27, 2017 Unapproved 5,989 1.80 1.78 0.64 3.00 0.23 % July 18, 2017 Unapproved 11,825 1.83 1.83 0.66 3.00 0.26 % October 24, 2017 Unapproved 12,264 1.80 1.70 0.57 3.00 0.46 % April 20, 2018 Unapproved 9,514 2.05 2.05 0.69 3.00 0.79 % October 19, 2018 Unapproved 4,324,198 0.30 0.30 0.09 3.00 0.81 % October 19, 2018 Unapproved 3,814,970 0.30 0.30 0.12 3.00 0.90 % 9,168,396 The key assumptions used in calculating the share-based payments are as follows: a. Black-Scholes valuation methodology was used for all share options issued since 2016. These options do not have market-based performance related conditions. b. The majority of share option awards made before 2016 had market-based performance related conditions and have been modeled using the Monte-Carlo methodology. The options granted on January 31, 2013, and December 18, 2013, do not have market-based performance related conditions. c. Figures in the range of 39% - 134% have been used for expected volatility. This has been derived from historic share price performance, weighted to exclude periods of unusually high volatility. d. Expected dividend yield is nil, consistent with the Directors’ view that the Group’s business model is to generate value through capital growth rather than the payment of dividends. e. The risk-free rate is equal to the prevailing U.K. Gilts rate at grant date that most closely matches the expected term of the grant. f. Share options are assumed to be exercised immediately on vesting. g. The fair value of share options awarded where there are different vesting installments is the average of the fair values calculated per installment. 26 . Share option scheme and restricted stock units (continued) At January 31, 2019 , the outstanding restricted stock units (‘RSUs’) in the form of nominal-cost options, which have been granted to non-executive directors, are shown below: Date of grant Exercise price (£) Number of shares Date from which exercisable Expiry date April 20, 2018 0.01 121,950 April 20, 2019 December 31, 2019 January 11, 2019 0.01 692,306 January 11, 2020 December 31, 2020 814,256 The movement in the number of RSUs is set out below: Weighted Year ended January 31, 2019 Weighted Year ended January 31, 2018 Outstanding at February 1, 0.01 275,877 — — Granted during the year 0.01 814,256 0.01 275,877 Exercised during the year 0.01 (275,877 ) — — Number of RSUs outstanding at January 31, 0.01 814,256 0.01 275,877 As at January 31, 2019 , nil RSUs were capable of being exercised ( 2018 : nil ). The RSUs outstanding at January 31, 2019 , had a weighted average exercise price per RSU of 1 penny ( 2018 : 1 penny), and a weighted average remaining contractual life of 1.8 years (2018: 0.9 years). The fair value per RSU award granted and the assumptions used in the calculations are as follows: Date of grant Number of shares Exercise price (£) Share price at grant date (£) Fair value per option (£) Award life (years) Risk free rate April 20, 2018 121,950 0.01 2.05 2.04 1.00 0.70 % January 11, 2019 692,306 0.01 0.26 0.25 1.00 0.79 % 814,256 The key assumptions used in calculating the share-based payments are as follows: a. Black-Scholes valuation methodology was used for all RSUs. b. Figures in the range of 50% - 57% have been used for expected volatility. This has been derived from historic share price performance, weighted to exclude periods of unusually high volatility. c. Expected dividend yield is nil, consistent with the Directors’ view that the Group’s business model is to generate value through capital growth rather than the payment of dividends. d. The risk-free rate is equal to the prevailing U.K. Gilts rate at grant date that most closely matches the expected term of the grant. e. RSUs are assumed to be exercised immediately on vesting.

Fixed assets purchase commitmen

Fixed assets purchase commitments	12 Months Ended
	Jan. 31, 2019
Fixed Assets Purchase Commitments [Abstract]
Fixed assets purchase commitments	Fixed assets purchase commitments At January 31, 2019 , the Group had no capital commitments ( January 31, 2018 : nil ).

Leasing and other commitments

Leasing and other commitments	12 Months Ended
	Jan. 31, 2019
Disclosure of recognised finance lease as assets by lessee [abstract]
Leasing and other commitments	Leasing and other commitments The Group’s total commitments under non-cancelable operating leases are as follows: Land & Buildings January 31, 2019 January 31, 2018 £000 £000 Leases which expire Not later than one year 357 337 Later than one year and not later than five years 723 1,143 1,080 1,480 In addition to land and buildings, the Group enters into contracts in the normal course of business with contract research organizations to assist in the performance of research and development activities and other services and products for operating purposes. These contracts generally provide for termination on notice, and therefore are cancelable contracts and not reflected in the table above.

Related party transactions

Related party transactions	12 Months Ended
	Jan. 31, 2019
Disclosure of transactions between related parties [abstract]
Related party transactions	Related party transactions Professor Stephen Davies, a non-executive director who resigned in September 2018, is a member of the board of directors of Oxford University Innovation Limited. During the year, £ nil ( 2018 : £24,000 ) was charged by Oxford University Innovation Limited in connection with payments due in respect of the strategic alliance between the Group and Oxford University that was entered into in November 2013. Of this amount, £ nil was outstanding at the year end ( 2018 : £12,000 ). See Note 7 ‘ Directors and employees ’ for details of key management emoluments.

Basis of accounting (Policies)

Basis of accounting (Policies)	12 Months Ended
	Jan. 31, 2019
Basis Of Presentation [Abstract]
Basis of preparation	Basis of preparation The Consolidated Financial Statements have been prepared in accordance with International Financial Reporting Standards and IFRS Interpretations Committee interpretations ('IFRS') as issued by the IASB. The Consolidated Financial Statements have been prepared on a going concern basis and under the historical cost convention modified by revaluation of financial assets and financial liabilities held at fair value through profit and loss. These Consolidated Financial Statements were authorized by the Board of Directors on March 27, 2019.
Going concern	Going concern The financial information in these financial statements has been prepared assuming the Group will continue on a going concern basis. Based on management's forecasts, the Group's existing cash and cash equivalents, anticipated payments from BARDA under its contract for the development of ridinilazole, anticipated payments from CARB-X under its contract for the development of its gonorrhea antibiotic candidate, and anticipated payments from the cost-sharing arrangement under its license and collaboration agreement with Sarepta are expected to be sufficient to enable the Group to fund its operating expenses and capital expenditure requirements through January 31, 2020. The Group will need to raise additional funding in order to support, beyond this date, its planned research and development efforts, potential commercialization related activities, if any of its product candidates receive marketing approval, as well as to support activities associated with operating as a public company in the United States and the United Kingdom. Should the Group be unable to raise additional funding, management has the ability to take mitigating action to fund its operating expenses and capital expenditure requirements in relation to its clinical development activities for only a short period beyond 12 months from the date of issuance of these financial statements. These circumstances represent a material uncertainty which may cast and raise significant doubt on the Group’s ability to continue as a going concern. These financial statements do not contain any adjustments that might result if the Group was unable to continue as a going concern. The Group is evaluating various options to finance its cash needs through a combination of some, or all, of the following: equity offerings, collaborations, strategic alliances, grants and clinical trial support from government entities, philanthropic, non-government and not-for-profit organizations and patient advocacy groups, debt financings, and marketing, distribution or licensing arrangements. Whilst the Group believes that funds would be available in this manner before the end of January 2020, there can be no assurance that the Group will be able to generate funds, on terms acceptable to the Group, on a timely basis or at all, which would impact the Group’s ability to continue as a going concern. The failure of the Group to obtain sufficient funds on acceptable terms when needed could have a material adverse effect on the Group’s business, results of operations and financial condition.
Use of estimates	Use of estimates The preparation of the financial statements, in conformity with IFRS, requires the use of estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Although these estimates are based on management’s best knowledge of the amount, event or actions, actual results may ultimately differ from those estimates. The areas involving higher degree of judgment or complexity, or areas where assumptions and estimates are significant to the Consolidated Financial Statements are disclosed in Note 2 ‘ Critical accounting judgments and key sources of estimation uncertainty .’
Basis of consolidation	Basis of consolidation The Consolidated Financial Statements incorporate the financial statements of the Group and entities controlled by the Group made up to the reporting date. Control is achieved where the Company has the power to govern the financial and operating policies of an investee entity so as to obtain benefits from its activities. The results of subsidiary undertakings acquired or disposed of in the year are included in the Consolidated Statement of Comprehensive Income from the effective date of acquisition or up to the effective date of disposal, as appropriate. Where necessary, adjustments are made to the financial statements of subsidiaries to bring the accounting policies used into line with those used by the Group. All intra-group transactions, balances, income and expenses are eliminated on consolidation.
Revenue recognition	Revenue recognition Revenue is accounted for in line with principles of IFRS 15 Revenue from contracts with customers . Licensing agreements may consist of multiple elements and provide for varying consideration terms, such as upfront, development, regulatory and sales milestones, sales-based royalties and similar payments. Such arrangements are determined to be within the scope of IFRS 15 and are assessed under the five-step model of the standard to determine revenue recognition. The distinct performance obligations within the contract and the arrangement transaction price are identified. The fair value of the arrangement transaction price is allocated to the different performance obligations based on the relative stand-alone selling price of those services provided and the performance obligation activities to which the terms of the payments specifically relate to. The allocated transaction price is recognized over the respective performance period of each performance obligation. Amounts received in advance of the revenue recognition criteria being met are initially reported as deferred revenue on the Consolidated Statement of Financial Position and are recognized as revenue over the development period. Development and regulatory approval milestone payments are included within the allocated transaction price only when it becomes highly probable that a significant reversal in the amount of cumulative revenue recognized will not occur. Revenues attributable to the development cost share element of a licensing agreement are also recognized over the performance period. Sales-based royalty income and related milestone payments are recognized in the period when the related sales occur or when the relevant milestone is achieved, as the license granted is the predominant element of the performance obligation and the payments are inherently received once the development period is completed and the license granted is useable. See Note 3 ‘ Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers ’ for details of the impact of the initial adoption of IFRS 15.
Business Combinations	Business Combinations The cost of an acquisition is measured as the fair value of the assets exchanged, equity instruments issued and liabilities incurred or assumed at the date of exchange. Identifiable assets acquired together with liabilities and contingent liabilities assumed in a business combination are measured initially at their fair values at the acquisition date. The excess of the cost of acquisition over the fair value of the identifiable net assets is recorded as goodwill. Goodwill is not amortized but is reviewed for impairment at least annually and more frequently whenever there is an indication of impairment.
Intangible Assets	Intangible Assets In-process research and development that is separately acquired as part of a company acquisition or in-licensing agreement is capitalized even if they have not yet demonstrated technical feasibility, which is usually signified by regulatory approval. Amortization will commence when either products underpinned by the intellectual property rights or the rights themselves become available for use . Intangible assets not subject to amortization are tested for impairment at least annually or whenever there is an indicator of impairment. The intangible asset relating to the acquired Discuva Platform capitalized as part of the acquisition of Discuva Limited in December 2017 is available for use. As such, it is subject to amortization over the period of the relevant associated patents. Other intangible assets are amortized in equal installments over their useful estimated lives as follows: All patents (once filed) Over the period of the relevant patents (assumed to be 20 years) Software licenses 3-5 years Option over non-financial assets Over the period of the relevant agreement
Impairment of assets	Impairment of assets At each year end date, the Group reviews the carrying amounts of its tangible and intangible assets to determine whether there is any indication that those assets have suffered an impairment loss. For the purposes of assessing impairment, assets are grouped at the lowest levels for which there are separately identifiable cash flows (cash-generating units). An impairment loss is recognized for the amount by which the asset’s or cash-generating unit’s carrying amount exceeds its recoverable amount. The recoverable amount is the higher of fair value, reflecting market conditions less costs to sell, and value in use based on an internal discounted cash flow evaluation, where appropriate. Impairment losses recognized for cash-generating units are charged pro rata to the other assets in the cash generating unit. All tangible and intangible assets are subsequently reassessed for indications that an impairment loss previously recognized may no longer exist. See Note 15 ‘ Intangible assets ’ for details.
Property, plant and equipment	Property, plant and equipment are stated at cost less depreciation. Cost comprises the purchase price plus any incidental costs of acquisition and commissioning. Depreciation is calculated to write-off the cost, less residual value, in equal annual installments over their estimated useful lives as follows: Leasehold improvements Over the period of the remaining lease Laboratory equipment 2-10 years Office and IT equipment 3-5 years The residual value, if not insignificant, is reassessed annually.
Financial liabilities on funding arrangements	When entering into funding agreements with charitable and not for profit organizations, management is required to assess whether, based on the terms of the agreement, they can avoid a transfer of cash by settling using a non-financial obligation. Under IFRS, when such arrangements also give the counterparties rights over unexploited intellectual property, all or part of the funding agreement should be accounted for as a financial liability recognized in the Statement of Financial Position rather than as a charitable grant. Financial liabilities are initially recognized at fair value using a discounted cash flow model with the difference between the fair value of the liability and the cash received considered to represent a charitable grant. The financial liabilities are subsequently measured at amortized cost using discounted cash flow models which calculate the risk adjusted net present values of estimated potential future cash flows for the relevant project. The financial liabilities are remeasured when there is a specific significant event that provides evidence of a significant change in the probability of successful development such as the completion of a phase of research or public reporting of significant interim data and changes in use or market for a product. The model is updated for changes in the clinical probability of success and other associated assumptions with the discount factor remaining unchanged within the model.
Provisions	Provisions Provisions are recognized when the Group has a present obligation (legal or constructive) as a result of a past event, where it is probable that an outflow of resources will be required to settle the obligation, and where a reliable estimate can be made of the amount of the obligation. If the effect of the time value of money is material, the expected future cash flows will be discounted using a pre-tax risk-free discount rate.
Other operating income	Other operating income Other operating income includes income received and recognized from government agencies, philanthropic, non-government, not for profit organizations and patient advocacy groups which are accounted for in accordance with IAS 20, ‘Accounting for Government Grants and Disclosure of Government Assistance.’ Monies received through these means are held as deferred income in the Consolidated Statement of Financial Position and are released to the Consolidated Statement of Comprehensive Income as the underlying expenditure is incurred and to the extent the conditions of the grant are met.
Foreign currencies	Foreign currencies Transactions in foreign currencies are recorded at the rate ruling at the date of the transaction. Monetary assets and liabilities denominated in foreign currencies are translated at the rate of exchange ruling at the year end date. All differences are taken to the Consolidated Statement of Comprehensive Income. Assets and liabilities of subsidiaries that have a functional currency different from the presentation currency (Pound Sterling) are translated at the closing rate at the date of each statement of financial position presented. Income and expenses are translated at average exchange rates. Any resulting differences are recognized in other comprehensive income/(loss) in the Consolidated Statement of Comprehensive Income.
Employee benefits	Employee benefits All employee benefit costs, notably holiday pay, bonuses and contributions to Group or personal defined contribution pension schemes are charged to the Consolidated Statement of Comprehensive Income on an accruals basis.
Operating leases	Operating leases Costs in respect of operating leases are charged to the Consolidated Statement of Comprehensive Income on a straight line basis over the lease term. Assets relating to lease incentives and dilapidation provisions are depreciated over the life of the lease and are included in property, plant and equipment as leasehold improvements.
Research and development	Research and development All ongoing research expenditure is currently expensed in the period in which it is incurred. Due to the regulatory environment inherent in the development of the Group’s products, the criteria for development costs to be recognized as an asset, as set out in IAS 38 ‘ Intangible Assets, ’ are not met until a product has received regulatory approval, and it is probable that future economic benefit will flow to the Group. The Group currently has no qualifying expenditure.
Cash and cash equivalents	Cash and cash equivalents Cash and cash equivalents include cash in hand and deposits held on call with the bank.
Share-based payments	Share-based payments In accordance with IFRS 2 ‘ Share-based Payment, ’ share options and restricted stock units are measured at fair value at their grant date. The fair value for the majority of the options is calculated using the Black-Scholes formula and charged to the Consolidated Statement of Comprehensive Income on a straight-line basis over the expected vesting period. For those options issued with vesting conditions other than remaining in employment (for example, those conditional upon the Group achieving certain predetermined financial criteria) a simulation model has been used. At each year end date, the Group revises its estimate of the number of options that are expected to become exercisable. This estimate is not revised according to estimates of changes in market based conditions.
Current taxation	Current taxation Income tax is recognized or provided at amounts expected to be recovered or paid using the tax rates and tax laws that have been enacted or substantively enacted at the year end date. Current tax includes research and development tax credits which are calculated in accordance with the U.K. research and development tax credit regime applicable to small and medium sized companies. Research and development expenditure which is not eligible for reimbursement under the small and medium sized companies regime, such as expenditure incurred on projects for which we receive income, may be reimbursed under the U.K. Research and Development Expenditure Credit (‘RDEC’) scheme. Receipts under the RDEC scheme are presented within other operating income as they are similar in nature to grant income.
Deferred taxation	Deferred taxation Deferred tax assets and liabilities are recognized where the carrying amount of an asset or liability in the Consolidated Statement of Financial Position differs from its tax base, except for differences arising on: • the initial recognition of goodwill; • the initial recognition of an asset or liability in a transaction which is not a business combination and at the time of the transaction affects neither accounting or taxable profit; and • investments in subsidiaries and jointly controlled entities where the Group is able to control the timing of the reversal of the difference, and it is probable that the difference will not reverse in the foreseeable future. Recognition of deferred tax assets is restricted to those instances where it is probable that taxable profit will be available against which the difference can be utilized. The amount of the asset or liability is determined using tax rates that have been enacted or substantively enacted by the reporting date and are expected to apply when the deferred tax liabilities/(assets) are settled/(recovered).
Financial instruments	Financial instruments The Group recognizes financial assets and liabilities in the respective categories ‘Financial assets at amortized cost’ and ‘Financial liabilities measured at amortized cost.’ Financial assets at amortized cost are non-derivative financial assets which are held to collect the contractual cash flows on specified dates. They arise when the Group provides money, goods or services directly to the debtor with no intention of trading the receivable. They are included in current assets, except for maturities greater than 12 months after the year end date, which are classified as non-current assets. Other liabilities consist of trade and other payables, being balances arising in the course of normal business with suppliers, contractors and other service providers, and borrowings, being loans and hire purchase funds advanced for the refit of leasehold premises and the purchase of laboratory equipment, fixtures and fittings. Financial assets at amortized cost, and other liabilities are initially recorded at fair value, and thereafter at amortized cost, if the timing difference is deemed to impact the fair value of the asset or liability. The Group assesses at each year end date the expected credit losses of a financial asset or a group of financial assets with consideration given to the risk of default occurring. Expected credit losses are the difference between the contractual cash flows due to the Group and the cash flows the Group expects to receive. The Group does not hold or trade in derivative financial instruments.
Warrants	Warrants Warrants issued by the Group are recognized and classified as equity when upon exercise, the Company would issue a fixed amount of its own equity instruments (ordinary shares) in exchange for a fixed amount of cash or another financial asset. Consideration received, net of incremental costs directly attributable to the issue of such new warrants, is shown in equity. Such warrants are not remeasured at fair value in subsequent reporting periods.

Basis of accounting (Tables)

Basis of accounting (Tables)	12 Months Ended
	Jan. 31, 2019
Basis Of Presentation [Abstract]
Schedule of other intangible assets, useful life	At each year end date, the Group reviews the carrying amounts of its tangible and intangible assets to determine whether there is any indication that those assets have suffered an impairment loss. For the purposes of assessing impairment, assets are grouped at the lowest levels for which there are separately identifiable cash flows (cash-generating units).
Schedule of property, plant and equipment, useful life	over their estimated useful lives as follows: Property, plant and equipment Cost Leasehold improvements £000 Laboratory equipment £000 Office and IT equipment £000 Total £000 At February 1, 2018 340 299 486 1,125 Additions — 62 57 119 Disposals — (22 ) (52 ) (74 ) Revaluation — — 5 5 At January 31, 2019 340 339 496 1,175 Accumulated depreciation At February 1, 2018 (31 ) (36 ) (249 ) (316 ) Charge for the year (34 ) (156 ) (119 ) (309 ) Disposals — 21 47 68 Revaluation — — (2 ) (2 ) At January 31, 2019 (65 ) (171 ) (323 ) (559 ) Net book value At February 1, 2018 309 263 237 809 At January 31, 2019 275 168 173 616 Cost Leasehold improvements £000 Laboratory equipment £000 Office and IT equipment £000 Total £000 At February 1, 2017 9 19 284 312 Acquisition of subsidiary — 280 49 329 Additions 340 — 173 513 Disposals (9 ) — (14 ) (23 ) At January 31, 2018 340 299 486 1,125 Accumulated depreciation At February 1, 2017 (9 ) (17 ) (170 ) (196 ) Charge for the year (31 ) (19 ) (90 ) (140 ) Disposals 9 — 10 19 At January 31, 2018 (31 ) (36 ) (249 ) (316 ) Net book value At February 1, 2017 — 2 114 116 At January 31, 2018 309 263 237 809

Changes to accounting policies

Changes to accounting policies (Tables)	12 Months Ended
	Jan. 31, 2019
Disclosure of expected impact of initial application of new standards or interpretations [abstract]
Disclosure of expected impact of initial application of new standards or interpretations	International Accounting Standards (IAS/IFRS) Effective Date IFRS 9 Financial Instruments (as revised in 2014) January 1, 2018 Amendment to IFRS 2 Share Based Payments, Classification and Measurement of Share-based Payment Transactions January 1, 2018 Amendments resulting from Annual Improvements 2014–2016 Cycle January 1, 2018 IFRIC 22 Foreign Currency Transactions and Advance Consideration January 1, 2018 3 . Changes to accounting policies (continued) At the date of signing these Consolidated Financial Statements, the following standards, amendments and interpretations, which have not been applied in these financial statements, were in issue but not yet effective: International Accounting Standards (IAS/IFRS) Effective Date IFRS 16 Leases January 1, 2019 Amendments to IFRS 9 Financial Instruments, Prepayment Features with Negative Compensation January 1, 2019 Amendments to IAS 19 Employee Benefits, Plan amendments, curtailments or settlements January 1, 2019 Amendments resulting from Annual Improvements 2015–2017 Cycle January 1, 2019 IFRIC 23 Uncertainty over Income Tax Treatments January 1, 2019 Amendments to References to the Conceptual Framework in IFRS Standards January 1, 2020 Amendments to IFRS 3 Business Combinations, Definition of a Business January 1, 2020 The increase in non-current and current deferred revenue for the year ended January 31, 2018, and reduction in revenue recognized during the year ended January 31, 2018 , relate to the difference between the accounting treatment of the Sarepta development milestone payment and development cost share income under IAS 18 and IFRS 15, as described above, which is recognized as revenue over the remainder of the determined development period. Original Year ended January 31, 2018 Adjusted Year ended January 31, 2018 Impact Impact on Consolidated Statement of Financial Position £000s £000s £000s Non-current liabilities Deferred revenue (18,033 ) (27,270 ) (9,237 ) Current liabilities Deferred revenue (10,012 ) (13,834 ) (3,822 ) Equity Accumulated losses reserve (80,898 ) (93,957 ) (13,059 ) Original Year ended January 31, 2018 Adjusted Year ended January 31, 2018 Impact Impact on Consolidated Statement of Comprehensive Income £000s £000s £000s Revenue 25,419 12,360 (13,059 ) Loss for the year (7,131 ) (20,190 ) (13,059 ) Original Adjusted Impact Impact on Consolidated Statement of Cash Flows £000s £000s £000s Loss before income tax (10,893 ) (23,952 ) (13,059 ) Adjusted for: (Decrease) / increase in deferred revenue (2,482 ) 10,577 13,059 Impact on net cash used by operating activities (13,375 ) (13,375 ) —

Revenue (Tables)

Revenue (Tables)	12 Months Ended
	Jan. 31, 2019
Revenue [abstract]
Disclosure of detailed information about revenue	Year ended January 31, 2019 Year ended January 31, 2018 Year ended January 31, 2017 (Adjusted*) £000 £000 £000 Analysis of revenue by category: Licensing agreements 42,766 12,050 2,304 Research collaboration agreement 246 310 — 43,012 12,360 2,304
Disclosure of revenue from contracts with customers	Year ended January 31, 2019 Year ended January 31, 2018 Year ended January 31, 2017 (Adjusted*) £000 £000 £000 Analysis of revenue by geography: United States 42,267 12,008 2,304 Latin America 499 42 — Europe 246 310 — 43,012 12,360 2,304

Other operating income (Tables)

Other operating income (Tables)	12 Months Ended
	Jan. 31, 2019
Analysis of income and expense [abstract]
Disclosure of other operating income	Year ended January 31, 2019 Year ended January 31, 2018 Year ended January 31, 2017 £000 £000 £000 Analysis of other operating income by category: Income recognized in respect of BARDA 13,091 1,772 — Grant income 1,187 13 56 Income on remeasurement or derecognition of financial liabilities on funding arrangements (Note 21) 539 908 — Income recognized in respect of the Wellcome Trust — — 13 Research and development credit 333 23 3 Other income 6 9 — 15,156 2,725 72

Directors and employees (Tables

Directors and employees (Tables)	12 Months Ended
	Jan. 31, 2019
Disclosure Directors And Employees [Abstract]
Detailed disclosure about average number of employees	The average monthly number of employees of the Group, including Executive Directors, during the year was: Year ended January 31, 2019 Year ended January 31, 2018 Year ended January 31, 2017 Technical, research and development 45 34 23 Corporate and administration 29 26 21 74 60 44
Detailed disclosure about employee expense	Their aggregate remuneration comprised: Year ended January 31, 2019 Year ended January 31, 2018 Year ended January 31, 2017 £000 £000 £000 Wages and salaries 8,268 7,493 5,932 Social security costs 844 643 434 Other pension costs 390 350 332 Share-based payment 4,743 1,607 1,379 14,245 10,093 8,077 Included within wages and salaries are termination benefits of £0.2 million (2018: £ nil ). Key management of the Group are members of the Executive Management Team. Excluding the Chief Commercial Officer, who joined the Executive Management Team in February 2019, the aggregate amounts of key management compensation are set out below: Year ended January 31, 2019 Year ended January 31, 2018 Year ended January 31, 2017 £000 £000 £000 Short-term employee benefits Wages and salaries 1,406 1,520 1,252 Social security costs 168 162 98 1,574 1,682 1,350 Post-employment benefits Amounts paid in lieu of employer pension contributions 43 32 17 Other pension costs 11 14 11 54 46 28 Share-based payment 3,177 705 327 Total remuneration 4,805 2,433 1,705

Loss before income tax (Tables)

Loss before income tax (Tables)	12 Months Ended
	Jan. 31, 2019
Analysis of income and expense [abstract]
Loss before income tax	Year ended January 31, 2019 Year ended January 31, 2018 Year ended January 31, 2017 £000 £000 £000 Research and development Employee benefit expense 6,264 5,616 4,218 Share-based payment expense 1,091 327 374 Program related costs 29,868 21,810 13,605 Amortization of intangible assets 829 105 10 Other research and development costs 1,122 1,112 745 39,174 28,970 18,952 General and administration Employee benefit expense 3,238 2,870 2,480 Share-based payment expense 3,652 1,280 1,005 Foreign exchange (gain) / loss (491 ) 1,986 533 Depreciation of property, plant and equipment 309 141 48 Loss on disposal of assets 43 40 — Other general and administration costs 4,818 5,613 4,211 Loss on contingent consideration 754 — — Royalty expense 19 69 — 12,342 11,999 8,277

Auditors_ remuneration (Tables)

Auditors’ remuneration (Tables)	12 Months Ended
	Jan. 31, 2019
Analysis of income and expense [abstract]
Detailed disclosure about auditors' remuneration	During the year, the Group obtained the following services from the Group’s auditors at the cost detailed below: Year ended January 31, 2019 Year ended January 31, 2018 Year ended January 31, 2017 £000 £000 £000 Fees payable to the auditors and its associates for the audit of the Company and Consolidated Financial Statements 160 132 110 Fees payable to the auditors and its associates for other services: - Audit of the Company’s subsidiaries (1) 119 209 120 - Audit-related assurance services — — 3 - Other assurance services (2) 115 118 163 - Tax compliance and advisory services 25 23 62 Total fees payable 419 482 458 (1) For the year ended January 31, 2018, fees payable for the Consolidated Financial Statements and fees payable for the Company's subsidiaries include audit services relating to the initial audit and business combination accounting for Discuva Limited. These were non-recurring fees. (2) For the year ended January 31, 2019, other assurance services includes reporting in connection with the Company’s registration statement on Form F-3 that was filed with the SEC on May 15, 2018. For the year ended January 31, 2018, other assurance services includes reporting in connection with the Company's underwritten public offering completed on September 18, 2017. These amounts were recognized directly in share premium. For the year ended January 31, 2017, other assurance services includes reporting in connection with the Company’s registration statement on Form F-3 that was originally filed with the SEC on May 12, 2016.

Finance income and costs (Table

Finance income and costs (Tables)	12 Months Ended
	Jan. 31, 2019
Disclosure of finance income and costs [Abstract]
Schedule of finance income (costs)	Note Year ended January 31, 2019 Year ended January 31, 2018 Year ended January 31, 2017 £000 £000 £000 Finance income Remeasurement or derecognition of financial liabilities on funding arrangements 21 2,784 3,085 — Interest income on deposits 4 11 8 Finance income 2,788 3,096 8 Finance costs Unwinding of discount factor 21 (424 ) (754 ) (862 ) Remeasurement of financial liabilities on funding arrangements 21 — (410 ) — Finance costs (424 ) (1,164 ) (862 )

Income tax (Tables)

Income tax (Tables)	12 Months Ended
	Jan. 31, 2019
Disclosure Of Income Tax [Abstract]
Reconciliation of income tax charge	Year ended January 31, 2019 Year ended January 31, 2018 Year ended January 31, 2017 £000 £000 £000 Analysis of credit in the period Current tax : Current tax income 1,286 3,767 4,245 Adjustments in respect of prior years 506 (5 ) (9 ) Total current tax 1,792 3,762 4,236 Total deferred tax 704 — 100 Total tax 2,496 3,762 4,336
Analysis of income tax charge	The difference between the total tax shown above and the amount calculated by applying the standard rate of U.K. corporation tax to the loss before tax is as follows: Year ended January 31, 2019 Year ended January 31, 2018 Year ended January 31, 2017 (Adjusted*) £000 £000 £000 Profit / (loss) before tax 5,031 (23,952 ) (25,707 ) Profit / (loss) multiplied by the standard rate of corporation tax in the United Kingdom (Current tax) 19% (2018: 19.17%) 956 (4,592 ) (5,141 ) Adjustment for IFRS 15 restatement (2,481 ) 2,504 — Change in unrecognized tax losses 820 751 2,169 Non-deductible expenses 1,797 402 331 Tax relief for qualifying research and development expenditure (2,656 ) (3,043 ) (1,699 ) Prior year adjustments (506 ) 5 9 Share options exercised (15 ) (40 ) (84 ) Overseas profits taxed at different rates 292 251 179 Change in rate of deferred tax (703 ) — (100 ) Total tax (2,496 ) (3,762 ) (4,336 ) * See Note 3 - ‘ Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers. ’

Earnings _ (loss) per share (Ta

Earnings / (loss) per share (Tables)	12 Months Ended
	Jan. 31, 2019
Earnings per share [abstract]
Earnings / (loss) per share calculation	The calculation of earnings / (loss) per share is based on the following data: Year ended January 31, 2019 Year ended January 31, 2018 Year ended January 31, 2017 (Adjusted*) 000s 000s 000s Profit / (loss) for the year £ 7,527 £ (20,190 ) £ (21,371 ) Weighted average number of ordinary shares for basic earnings / (loss) earnings per share 85,702 65,434 61,549 Effect of dilutive potential ordinary shares (share options and warrants) 442 — — Weighted average number of ordinary shares for diluted earnings per share 86,144 65,434 61,549 Basic earnings / (loss) per ordinary share from operations £ 0.09 (0.31 ) (0.35 ) Diluted earnings / (loss) per ordinary share from operations £ 0.09 (0.31 ) (0.35 ) * See Note 3 - ‘ Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers. ’

Goodwill (Tables)

Goodwill (Tables)	12 Months Ended
	Jan. 31, 2019
Disclosure of detailed information about intangible assets [abstract]
Disclosure of reconciliation of changes in goodwill	Discuva Limited £000 MuOx Limited £000 Total £000 Cost At February 1, 2018 1,814 664 2,478 At January 31, 2019 1,814 664 2,478 Accumulated impairment At February 1, 2018 — — — Impairment — (664 ) (664 ) At January 31, 2019 — (664 ) (664 ) Net book amount At February 1, 2018 1,814 664 2,478 At January 31, 2019 1,814 — 1,814 Discuva Limited £000 MuOx Limited £000 Total £000 Cost At February 1, 2017 — 664 664 Additions 1,814 — 1,814 At January 31, 2018 1,814 664 2,478 Accumulated impairment At February 1, 2017 — — — At January 31, 2018 — — — Net book amount At February 1, 2017 — 664 664 At January 31, 2018 1,814 664 2,478

Intangible assets (Tables)

Intangible assets (Tables)	12 Months Ended
	Jan. 31, 2019
Disclosure of detailed information about intangible assets [abstract]
Disclosure of reconciliation of changes in intangible assets	Utrophin Discuva Platform acquired Option over non-financial assets Other Total Cost At February 1, 2018 3,321 10,670 668 265 14,924 Additions — — — 6 6 Disposals — — — (49 ) (49 ) At January 31, 2019 3,321 10,670 668 222 14,881 Accumulated amortization At February 1, 2018 — (79 ) (4 ) (56 ) (139 ) Charge for the year — (739 ) (45 ) (45 ) (829 ) Impairment (3,321 ) — — — (3,321 ) Disposals — — — 12 12 At January 31, 2019 (3,321 ) (818 ) (49 ) (89 ) (4,277 ) Net book amount At February 1, 2018 3,321 10,591 664 209 14,785 At January 31, 2019 — 9,852 619 133 10,604 Iminosugar Utrophin Discuva Platform acquired Option over non-financial assets Other Total Cost At February 1, 2017 1,380 3,321 — — 204 4,905 Acquisition of subsidiary — — 10,670 668 — 11,338 Additions — — — — 119 119 Disposals (1,380 ) — — — (58 ) (1,438 ) At January 31, 2018 — 3,321 10,670 668 265 14,924 Accumulated amortization At February 1, 2017 (1,380 ) — — — (55 ) (1,435 ) Charge for the year — — (79 ) (4 ) (23 ) (106 ) Disposals 1,380 — — — 22 1,402 At January 31, 2018 — — (79 ) (4 ) (56 ) (139 ) Net book amount At February 1, 2017 — 3,321 — — 149 3,470 At January 31, 2018 — 3,321 10,591 664 209 14,785

Property, plant and equipment (

Property, plant and equipment (Tables)	12 Months Ended
	Jan. 31, 2019
Disclosure of detailed information about property, plant and equipment [abstract]
Disclosure of detailed information about property, plant and equipment	Property, plant and equipment Cost Leasehold improvements £000 Laboratory equipment £000 Office and IT equipment £000 Total £000 At February 1, 2018 340 299 486 1,125 Additions — 62 57 119 Disposals — (22 ) (52 ) (74 ) Revaluation — — 5 5 At January 31, 2019 340 339 496 1,175 Accumulated depreciation At February 1, 2018 (31 ) (36 ) (249 ) (316 ) Charge for the year (34 ) (156 ) (119 ) (309 ) Disposals — 21 47 68 Revaluation — — (2 ) (2 ) At January 31, 2019 (65 ) (171 ) (323 ) (559 ) Net book value At February 1, 2018 309 263 237 809 At January 31, 2019 275 168 173 616 Cost Leasehold improvements £000 Laboratory equipment £000 Office and IT equipment £000 Total £000 At February 1, 2017 9 19 284 312 Acquisition of subsidiary — 280 49 329 Additions 340 — 173 513 Disposals (9 ) — (14 ) (23 ) At January 31, 2018 340 299 486 1,125 Accumulated depreciation At February 1, 2017 (9 ) (17 ) (170 ) (196 ) Charge for the year (31 ) (19 ) (90 ) (140 ) Disposals 9 — 10 19 At January 31, 2018 (31 ) (36 ) (249 ) (316 ) Net book value At February 1, 2017 — 2 114 116 At January 31, 2018 309 263 237 809

Trade and other receivables (Ta

Trade and other receivables (Tables)	12 Months Ended
	Jan. 31, 2019
Trade and other receivables [abstract]
Prepayments and other receivables	January 31, 2019 January 31, 2018 £000 £000 Trade receivables 1,656 — Other receivables 3,847 3,600 Prepayments 7,433 6,498 Accrued income 611 1,036 13,547 11,134

Trade and other payables (Table

Trade and other payables (Tables)	12 Months Ended
	Jan. 31, 2019
Trade and other payables [abstract]
Components of trade and other payables	January 31, 2019 January 31, 2018 £000 £000 Trade payables 4,422 4,414 Other taxes and social security 190 164 Accruals 4,095 4,078 Other creditors 158 276 8,865 8,932

Deferred revenue and income (Ta

Deferred revenue and income (Tables)	12 Months Ended
	Jan. 31, 2019
Accruals and deferred income [abstract]
Detailed disclosure about deferred income	January 31, 2019 January 31, 2018 (Adjusted*) £000 £000 Due within one year Deferred revenue 499 11,478 Deferred other operating income 2,875 2,356 3,374 13,834 Due more than one year Deferred revenue 831 27,270 831 27,270 Total deferred revenue 1,330 38,748 Total deferred other operating income 2,875 2,356 * See Note 3 - ‘ Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers. ’

Financial liabilities on fund_2

Financial liabilities on funding arrangements (Tables)	12 Months Ended
	Jan. 31, 2019
Financial Liabilities At Amortised Cost [Abstract]
Reconciliation of financial liabilities on funding arrangements	January 31, 2019 January 31, 2018 £000 £000 At February 1 3,090 5,919 Unwinding of discount factor 233 754 Derecognition of financial liabilities – finance income — (3,085 ) Remeasurement of financial liabilities on funding arrangements - (2,784 ) 410 Net finance income on funding arrangements accounting for as financial liabilities (2,551 ) (1,921 ) Remeasurement or derecognition of financial liabilities – other operating income (539 ) (908 ) At January 31 — 3,090

Financial instruments (Tables)

Financial instruments (Tables)	12 Months Ended
	Jan. 31, 2019
Financial Instruments [Abstract]
Disclosure of detailed information about financial instruments	January 31, 2019 January 31, 2018 Note £000 £000 Financial assets at amortized cost Trade and other receivables (1) 17 5,503 3,600 Cash and cash equivalents 26,858 20,102 32,361 23,702 Financial liabilities measured at amortized cost Trade and other payables 18 8,865 8,932 Financial liabilities on funding arrangements 21 — 3,090 8,865 12,022 Financial liabilities measured at fair value through profit and loss Contingent consideration 20 629 — (1) Prepayments and accrued income have been excluded as they are not considered to be a financial instrument.
Disclosure of cash deposits	January 31, 2019 January 31, 2018 £000 £000 Cash at bank and in hand Pounds Sterling 3,363 5,535 U.S. Dollar 23,495 14,567 26,858 20,102 The Group’s cash and short-term deposits were as follows: January 31, 2019 January 31, 2018 £000 £000 On current account 26,858 20,102 26,858 20,102
Sensitivity analysis for types of market risk	The Group’s exposure to interest rate risk is illustrated with regard to the opening and closing cash balances and the difference that an increase or decrease of 1% in interest rates would have made based on the average cash balance of £ 23.5 million ( 2018 : £ 24.1 million ) in the year: Year ended January 31, 2019 (1)% Actual 1% Interest rate — 0.02 1.02 Interest received (£000) — 4 239 Year ended January 31, 2018 (1)% Actual 1% Interest rate — 0.02 1.02 Interest received (£000) — 5 246

Provisions for other liabilit_2

Provisions for other liabilities and charges and contingent liabilities (Tables)	12 Months Ended
	Jan. 31, 2019
Disclosure of contingent liabilities [abstract]
Provisions for other liabilities and charges and contingent liabilities	Assumed contingent liabilities £000s Dilapidations £000s Royalties £000s Total At February 1, 2018 1,466 150 25 1,641 Additions — — 19 19 Unwinding of the discount factor 191 — — 191 At January 31, 2019 1,657 150 44 1,851 Assumed contingent liabilities £000s Dilapidations £000s Royalties £000s Total At February 1, 2017 — 85 — 85 Additions 1,466 150 25 1,641 Used during the year — (85 ) — (85 ) At January 31, 2018 1,466 150 25 1,641
Disclosure of contingent liabilities in business combination	Contingent consideration During the financial year, the Group reassessed the contingent consideration in line with the anticipated settlement of consideration liabilities relating to the acquisition of Discuva Limited ('Discuva') in December 2017. The Group estimated the total expected additional cash outflows to be £0.8 million , w hich is based on the terms of the share purchase agreement. The additional expected payment is primarily due to research and development tax credits received and receivable by Discuva in respect of financial years prior to the Group's acquisition, of which the sellers are due a specified portion of these amounts. During the year ended January 31, 2019 , a payment of £0.2 million was made for the research and development tax credits received, leaving an estimated contingent consideration liability of £0.6 million . The table below describes the value of the assumed contingent liabilities as at January 31, 2019 , of £1.7 million compared to what the total value would be following the presented variations to the underlying assumptions in the model: January 31, 2019 £000s Estimated assumed contingent liabilities 1,658 1% lower discount rate 1,770 1% higher discount rate 1,560 10% lower probability of success 1,366 10% higher probability of success 1,927

Deferred tax liability (Tables)

Deferred tax liability (Tables)	12 Months Ended
	Jan. 31, 2019
Deferred tax assets and liabilities [abstract]
Detailed disclosure about deferred tax liability	Year ended January 31, 2019 Year ended January 31, 2018 £000 £000 Amounts falling due after more than one year At February 1 2,379 565 Release of temporary difference relating to the intangible asset (704 ) — Acquisition of subsidiary — 1,814 At January 31 1,675 2,379

Share capital (Tables)

Share capital (Tables)	12 Months Ended
	Jan. 31, 2019
Disclosure Of Share Capital, Reserves And Other Equity Interest [Abstract]
Disclosure of share capital	January 31, 2019 January 31, 2018 £000 £000 Allotted, called up and fully paid 160,389,881 (2018: 73,563,624) Ordinary Shares of 1p each 1,604 736
Reconciliation of share capital and share premiums	Changes to the number of ordinary shares in issue have been as follows: Number of shares Total nominal value £000 Total share premium £000 Total consideration £000 At February 1, 2017 61,841,566 618 46,420 47,038 New share capital issued (net of transaction costs) 8,389,250 84 13,419 13,503 Issue of ordinary shares as consideration for a business combination (1) 2,934,272 30 — 30 New share capital issued from exercise of warrants 50,000 1 9 10 Share options exercised 348,536 3 389 392 At January 31, 2018 73,563,624 736 60,237 60,973 At February 1, 2018 73,563,624 736 60,237 60,973 New share capital issued (net of transaction costs) 86,458,333 864 32,471 33,335 Share options exercised 367,924 4 98 102 At January 31, 2019 160,389,881 1,604 92,806 94,410 (1) The difference between the nominal value of the share capital acquired in Discuva Limited and fair value of shares issued in the business combination using the acquisition method of accounting was recognized as part of the Group's merger reserve arising as a result of certain requirements in the United Kingdom.
Detailed disclosure about share capital, options exercised	During the year to January 31, 2019 , the following exercises of share options and restricted stock units took place: Date Number of options exercised March 16, 2018 4,216 April 18, 2018 38,850 April 23, 2018 48,981 July 18, 2018 136,991 October 24, 2018 138,886 367,924

Share option scheme and restr_2

Share option scheme and restricted stock units (Tables)	12 Months Ended
	Jan. 31, 2019
Disclosure Of Share-Based Payment Arrangements [Abstract]
Disclosure of number and weighted average remaining contractual life of outstanding share options	At January 31, 2019 , the outstanding share options, which include the share options granted to Directors, are shown below: Date of grant Exercise price (£) Number of shares Date from which exercisable Expiry date Approved EMI scheme April 7, 2011 0.65 5,873 April 8, 2014 April 7, 2021 May 10, 2012 0.60 150,046 May 10, 2014 May 10, 2022 December 24, 2012 0.85 21,500 December 24, 2015 December 24, 2022 January 31, 2013 0.20 72,973 July 31, 2013 January 31, 2023 July 15, 2014 1.26 100,000 July 15, 2016 July 15, 2024 June 23, 2016 1.05 58,564 June 23, 2017 June 23, 2026 408,956 Unapproved scheme December 18, 2013 0.20 76,364 June 18, 2014 December 18, 2023 July 15, 2014 1.26 175,000 July 15, 2016 July 15, 2024 July 15, 2014 0.80 100,000 May 30, 2015 May 30, 2023 January 21, 2015 1.23 75,000 January 21, 2017 January 21, 2025 June 23, 2016 0.01 110,576 July 21, 2016 June 23, 2026 June 23, 2016 1.05 43,740 June 23, 2017 June 23, 2026 June 27, 2017 1.80 5,989 June 27, 2017 June 27, 2027 July 18, 2017 1.83 11,825 June 18, 2018 June 18, 2027 October 24, 2017 1.80 12,264 October 24, 2018 October 24, 2027 April 20, 2018 2.05 9,514 April 23, 2019 April 23, 2028 October 19, 2018 0.30 4,324,198 October 19, 2019 October 19, 2028 October 19, 2018 0.30 3,814,970 October 19, 2021 October 19, 2028 8,759,440 9,168,396 At January 31, 2019 , the outstanding restricted stock units (‘RSUs’) in the form of nominal-cost options, which have been granted to non-executive directors, are shown below: Date of grant Exercise price (£) Number of shares Date from which exercisable Expiry date April 20, 2018 0.01 121,950 April 20, 2019 December 31, 2019 January 11, 2019 0.01 692,306 January 11, 2020 December 31, 2020 814,256
Additional information about share-based payment arrangements	The movement in the number of RSUs is set out below: Weighted Year ended January 31, 2019 Weighted Year ended January 31, 2018 Outstanding at February 1, 0.01 275,877 — — Granted during the year 0.01 814,256 0.01 275,877 Exercised during the year 0.01 (275,877 ) — — Number of RSUs outstanding at January 31, 0.01 814,256 0.01 275,877 The movement in the number of share options is set out below: Weighted average exercise price £ Year ended January 31, 2019 Weighted average exercise price £ Year ended January 31, 2018 Outstanding at February 1, 1.43 8,577,236 1.17 7,383,401 Granted during the year 0.76 13,081,048 1.83 2,972,903 Lapsed / surrendered during the year 1.52 (12,397,841 ) 0.99 (1,430,532 ) Exercised during the year 1.08 (92,047 ) 1.13 (348,536 ) Number of options outstanding at January 31, 0.35 9,168,396 1.43 8,577,236
Disclosure of number and weighted average exercise prices of share options	The fair value per share option award granted and the assumptions used in the calculations are as follows: Date of grant Type of award Number of shares Exercise price (£) Share price at grant date (£) Fair value per option (£) Award life (years) Risk free rate April 07, 2011 EMI 5,873 0.65 0.65 0.47 5.00 2.70 % May 10, 2012 EMI 150,046 0.60 0.52 0.24 5.00 1.00 % December 24, 2012 EMI 21,500 0.85 0.85 0.59 5.00 0.90 % January 31, 2013 EMI 72,973 0.20 0.94 0.74 5.00 1.00 % December 18, 2013 Unapproved 76,364 0.20 1.85 1.65 5.00 1.00 % July 15, 2014 EMI 100,000 1.26 1.26 0.65 3.00 1.30 % July 15, 2014 Unapproved 175,000 1.26 1.26 0.65 3.00 1.30 % July 15, 2014 Unapproved 100,000 0.80 0.81 0.65 1.90 0.50 % January 21, 2015 Unapproved 75,000 1.23 1.22 0.64 3.00 0.60 % June 23, 2016 EMI 58,564 1.05 1.05 0.25 3.00 0.30 % June 23, 2016 Unapproved 110,576 0.01 1.05 1.04 0.50 0.30 % June 23, 2016 Unapproved 43,740 1.05 1.05 0.25 3.00 0.30 % June 27, 2017 Unapproved 5,989 1.80 1.78 0.64 3.00 0.23 % July 18, 2017 Unapproved 11,825 1.83 1.83 0.66 3.00 0.26 % October 24, 2017 Unapproved 12,264 1.80 1.70 0.57 3.00 0.46 % April 20, 2018 Unapproved 9,514 2.05 2.05 0.69 3.00 0.79 % October 19, 2018 Unapproved 4,324,198 0.30 0.30 0.09 3.00 0.81 % October 19, 2018 Unapproved 3,814,970 0.30 0.30 0.12 3.00 0.90 % 9,168,396 The fair value per RSU award granted and the assumptions used in the calculations are as follows: Date of grant Number of shares Exercise price (£) Share price at grant date (£) Fair value per option (£) Award life (years) Risk free rate April 20, 2018 121,950 0.01 2.05 2.04 1.00 0.70 % January 11, 2019 692,306 0.01 0.26 0.25 1.00 0.79 % 814,256

Leasing and other commitments (

Leasing and other commitments (Tables)	12 Months Ended
	Jan. 31, 2019
Disclosure of recognised finance lease as assets by lessee [abstract]
Commitments under non-cancelable operating leases	The Group’s total commitments under non-cancelable operating leases are as follows: Land & Buildings January 31, 2019 January 31, 2018 £000 £000 Leases which expire Not later than one year 357 337 Later than one year and not later than five years 723 1,143 1,080 1,480

Basis of accounting - Narrative

Basis of accounting - Narrative (Details)	12 Months Ended
	Jan. 31, 2019year
Patent
Disclosure of detailed information about property, plant and equipment [line items]
Intangible asset, useful life	20
Bottom of range | Laboratory equipment
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment useful life	2
Bottom of range | Office equipment
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment useful life	3
Bottom of range | Software licenses
Disclosure of detailed information about property, plant and equipment [line items]
Intangible asset, useful life	3
Top of range | Laboratory equipment
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment useful life	10
Top of range | Office equipment
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment useful life	5
Top of range | Software licenses
Disclosure of detailed information about property, plant and equipment [line items]
Intangible asset, useful life	5

Changes to accounting policie_2

Changes to accounting policies - Narrative (Details) £ in Thousands, $ in Millions	Jan. 01, 2018	Jan. 31, 2019GBP (£)	Jan. 31, 2018GBP (£)	May 31, 2017USD ($)	May 31, 2017GBP (£)	Oct. 04, 2016USD ($)	Oct. 04, 2016GBP (£)
Disclosure of initial application of standards or interpretations [line items]
Deferred revenue		£ 1,330	£ 38,748
Increase Decrease Due To Application of IFRS16
Disclosure of initial application of standards or interpretations [line items]
Right-of-use assets		900
Lease liabilities		£ 900
Sarepta Revenue Agreement
Disclosure of initial application of standards or interpretations [line items]
Specified milestone payments				$ 22	£ 17,200	$ 22	£ 17,200
Deferred revenue						$ 40	£ 32,800
Research and development costs percentage, third party responsibility	45.00%	45.00%
Sarepta Revenue Agreement | Adjusted
Disclosure of initial application of standards or interpretations [line items]
Deferred revenue			13,100
Sarepta Revenue Agreement | Cost Share Income | Adjusted
Disclosure of initial application of standards or interpretations [line items]
Deferred revenue			700
Sarepta Revenue Agreement | Specified Development Milestones | Adjusted
Disclosure of initial application of standards or interpretations [line items]
Deferred revenue			£ 12,400

Changes to accounting policie_3

Changes to accounting policies - Disclosure of changes in accounting policy (Details) - GBP (£) £ in Thousands	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018		Jan. 31, 2017
Non-current liabilities
Deferred revenue	£ (831)	£ (27,270)	[1]
Current liabilities
Deferred revenue and income	(3,374)	(13,834)	[1]
EQUITY
Accumulated losses reserve	(76,092)	(93,957)	[1]
Statement of comprehensive income [abstract]
Revenue	43,012	12,360	[1]	£ 2,304
Profit / (loss) for the year	7,527	(20,190)	[1]	(21,371)
Statement of cash flows [abstract]
Profit / (loss) before income tax	£ 5,031	(23,952)	[1]	£ (25,707)
Adjusted for:
(Decrease) / increase in deferred revenue		10,577
Impact on net cash used by operating activities		(13,375)
Previously reported
Non-current liabilities
Deferred revenue		(18,033)
Current liabilities
Deferred revenue and income		(10,012)
EQUITY
Accumulated losses reserve		(80,898)
Statement of comprehensive income [abstract]
Revenue		25,419
Profit / (loss) for the year		(7,131)
Statement of cash flows [abstract]
Profit / (loss) before income tax		(10,893)
Adjusted for:
(Decrease) / increase in deferred revenue		(2,482)
Impact on net cash used by operating activities		(13,375)
Adjusted
Non-current liabilities
Deferred revenue		(9,237)
Current liabilities
Deferred revenue and income		(3,822)
EQUITY
Accumulated losses reserve		(13,059)
Statement of comprehensive income [abstract]
Revenue		(13,059)
Profit / (loss) for the year		(13,059)
Statement of cash flows [abstract]
Profit / (loss) before income tax		(13,059)
Adjusted for:
(Decrease) / increase in deferred revenue		13,059
Impact on net cash used by operating activities		£ 0
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Segmental reporting - Narrative

Segmental reporting - Narrative (Details)	Jan. 31, 2019entiysubsidiarysegment
Disclosure of operating segments [abstract]
Number of legal entities	11
Number of trading entities	4
Number of subsidiaries | subsidiary	10
Number of reportable segments | segment	1

Revenue - Analysis of revenue b

Revenue - Analysis of revenue by category (Details) - GBP (£) £ in Thousands	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018		Jan. 31, 2017
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	£ 43,012	£ 12,360	[1]	£ 2,304
Licensing agreements
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	42,766	12,050		2,304
Research collaboration agreement
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	£ 246	£ 310		£ 0
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Revenue - Analysis of revenue_2

Revenue - Analysis of revenue by geography (Details) - GBP (£) £ in Thousands	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018		Jan. 31, 2017
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	£ 43,012	£ 12,360	[1]	£ 2,304
United States
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	42,267	12,008		2,304
Latin America
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	499	42		0
Europe
Disclosure of disaggregation of revenue from contracts with customers [line items]
Revenue	£ 246	£ 310		£ 0
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Revenue - Narrative (Details)

Revenue - Narrative (Details) £ in Thousands, $ in Millions	Jan. 01, 2018	Jan. 31, 2019GBP (£)	Jan. 31, 2018GBP (£)	Dec. 21, 2017USD ($)	Dec. 21, 2017GBP (£)	May 31, 2017USD ($)	May 31, 2017GBP (£)	Oct. 04, 2016USD ($)	Oct. 04, 2016GBP (£)
Disclosure of disaggregation of revenue from contracts with customers [line items]
Deferred revenue		£ 1,330	£ 38,748
Sarepta Revenue Agreement
Disclosure of disaggregation of revenue from contracts with customers [line items]
Deferred revenue								$ 40	£ 32,800
Specified milestone payments						$ 22	£ 17,200	$ 22	£ 17,200
Research and development costs percentage, entity responsibility	55.00%
Research and development costs percentage, third party responsibility	45.00%	45.00%
Research and development costs, minimum percentage of budgeted amount	110.00%
Eurofarma Revenue Agreement
Disclosure of disaggregation of revenue from contracts with customers [line items]
Deferred revenue				$ 2.5	£ 1,900
Annual future expected deferred revenue recognition		£ 500
Eurofarma Revenue Agreement | Specified Development Milestones
Disclosure of disaggregation of revenue from contracts with customers [line items]
Specified milestone payments					3,750
Eurofarma Revenue Agreement | Other Milestones
Disclosure of disaggregation of revenue from contracts with customers [line items]
Specified milestone payments					21,400
Specified milestone payments, maximum cumulative net sales benchmark					£ 100,000

Other operating income (Details

Other operating income (Details) - GBP (£) £ in Thousands	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018		Jan. 31, 2017
Disclosure of operating segments [line items]
Income on remeasurement or derecognition of financial liabilities on funding arrangements	£ 539	£ 908		£ 0
Research and development credit	333	23		3
Other income	6	9		0
Other operating income	15,156	2,725	[1]	72
BARDA
Disclosure of operating segments [line items]
Grant income	13,091	1,772		0
Wellcome Trust
Disclosure of operating segments [line items]
Income recognized	0	0		13
CARB-X and Innovate
Disclosure of operating segments [line items]
Grant income	£ 1,187	£ 13		£ 56
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Other operating income - Textua

Other operating income - Textual (Details) £ in Millions, $ in Millions	1 Months Ended
	Jul. 31, 2018USD ($)	Aug. 31, 2018USD ($)	Sep. 30, 2017USD ($)	Jan. 31, 2017GBP (£)
BARDA
Disclosure of operating segments [line items]
Cost sharing arrangement, initial portion			$ 32
Cost sharing arrangement, additional portion		$ 12
Cost sharing arrangement, contractual amount, total committed amount		$ 44
CARB-X
Disclosure of operating segments [line items]
Cost sharing arrangement, contractual amount	$ 4.5
Cost sharing arrangement, contractual amount, total committed amount	2.5
Grant income, received	$ 2
Top of range | BARDA
Disclosure of operating segments [line items]
Cost sharing arrangement, contractual amount			$ 62
Top of range | Innovate UK
Disclosure of operating segments [line items]
Cost sharing arrangement, contractual amount | £				£ 1.1

Directors and employees - Numbe

Directors and employees - Number of employees (Details) - employee	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017
Disclosure of operating segments [line items]
Number of employees	74	60	44
Cost-cutting measures
Disclosure of operating segments [line items]
Number of employees	61	76
Technical, research and development
Disclosure of operating segments [line items]
Number of employees	45	34	23
Corporate and administration
Disclosure of operating segments [line items]
Number of employees	29	26	21

Directors and employees - Emplo

Directors and employees - Employee compensation (Details) - GBP (£)	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017
Disclosure Directors And Employees [Abstract]
Wages and salaries	£ 8,268,000	£ 7,493,000	£ 5,932,000
Social security costs	844,000	643,000	434,000
Other pension costs	390,000	350,000	332,000
Share-based payment	4,743,000	1,607,000	1,379,000
Employee benefits expense	14,245,000	10,093,000	£ 8,077,000
Termination benefits expense	£ 200,000	£ 0

Directors and employees - Manag

Directors and employees - Management compensation (Details) - GBP (£) £ in Thousands	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017
Short-term employee benefits
Wages and salaries	£ 1,406	£ 1,520	£ 1,252
Social security costs	168	162	98
Short-term employee benefits expense	1,574	1,682	1,350
Post-employment benefits
Amounts paid in lieu of employer pension contributions	43	32	17
Other pension costs	11	14	11
Key management personnel compensation, other long-term employee benefits	54	46	28
Share-based payment	3,177	705	327
Total remuneration	£ 4,805	£ 2,433	£ 1,705

Loss before income tax - Loss b

Loss before income tax - Loss before income tax (Details) - GBP (£) £ in Thousands	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018		Jan. 31, 2017
Research and development
Employee benefit expense	£ 14,245	£ 10,093		£ 8,077
Share-based payment expense	4,743	1,607		1,379
Amortization of intangible assets	829	106	[1]	10
Research and development expense	39,174	28,970	[1]	18,952
General and administration
Other operating income (expense)	12,342	11,999	[1]	8,277
Research and development
Research and development
Employee benefit expense	6,264	5,616		4,218
Share-based payment expense	1,091	327		374
Program related costs	29,868	21,810		13,605
Amortization of intangible assets	829	105		10
Other research and development costs	1,122	1,112		745
Research and development expense	39,174	28,970		18,952
General and administration
Research and development
Employee benefit expense	3,238	2,870		2,480
Share-based payment expense	3,652	1,280		1,005
General and administration
Foreign exchange (gain) / loss	(491)	1,986		533
Depreciation of property, plant and equipment	309	141		48
Loss on disposal of assets	43	40		0
Other general and administration costs	4,818	5,613		4,211
Loss on contingent consideration	754	0		0
Royalty expense	19	69		0
Other operating income (expense)	£ 12,342	£ 11,999		£ 8,277
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Impairment of goodwill and in_2

Impairment of goodwill and intangible assets (Details) - GBP (£) £ in Thousands	1 Months Ended	12 Months Ended
	Jun. 30, 2018	Jan. 31, 2019	Jan. 31, 2018	[1]	Jan. 31, 2017	Jul. 31, 2018
Disclosure of impairment loss and reversal of impairment loss [line items]
Impairment of goodwill and intangible assets		£ 3,985	£ 0		£ 0
Intangible assets		10,604	14,785		£ 3,470
Goodwill		£ 1,814	£ 2,478
MuOx Limited
Disclosure of impairment loss and reversal of impairment loss [line items]
Impairment of goodwill and intangible assets	£ 4,000
Intangible assets						£ 3,300
Goodwill						£ 700
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Auditors_ remuneration (Details

Auditors’ remuneration (Details) - GBP (£) £ in Thousands	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017
Auditor Renumeration [Line Items]
Auditor's remuneration for audit services	£ 160	£ 132	£ 110
Audit-related assurance services	0	0	3
Other assurance services	115	118	163
Tax compliance and advisory services	25	23	62
Total fees payable	419	482	458
Subsidiaries
Auditor Renumeration [Line Items]
Auditor's remuneration for audit services	£ 119	£ 209	£ 120

Finance income and costs (Detai

Finance income and costs (Details) - GBP (£) £ in Thousands	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018		Jan. 31, 2017
Finance income
Remeasurement or derecognition of financial liabilities on funding arrangements	£ 2,784	£ 3,085		£ 0
Interest income on deposits	4	11		8
Finance income	2,788	3,096	[1]	8
Finance costs
Unwinding of discount factor	(424)	(754)		(862)
Remeasurement of financial liabilities on funding arrangements	0	(410)		0
Finance costs	£ (424)	£ (1,164)	[1]	£ (862)
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Income tax - Tax (Details)

Income tax - Tax (Details) - GBP (£) £ in Thousands	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018		Jan. 31, 2017
Disclosure Of Income Tax [Abstract]
Current tax income	£ 1,286	£ 3,767		£ 4,245
Adjustments in respect of prior years	506	(5)		(9)
Total current tax	1,792	3,762		4,236
Total deferred tax	704	0		100
Total tax	£ 2,496	£ 3,762	[1]	£ 4,336
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Income tax - Tax reconciliation

Income tax - Tax reconciliation (Details) - GBP (£) £ in Thousands	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018		Jan. 31, 2017
Disclosure Of Income Tax [Abstract]
Profit / (loss) before tax	£ 5,031	£ (23,952)	[1]	£ (25,707)
Profit / (loss) multiplied by the standard rate of corporation tax in the United Kingdom (Current tax) 19% (2018: 19.17%)	956	(4,592)		(5,141)
Adjustment for IFRS 15 restatement	(2,481)	2,504		0
Change in unrecognized tax losses	820	751		2,169
Non-deductible expenses	1,797	402		331
Tax relief for qualifying research and development expenditure	(2,656)	(3,043)		(1,699)
Prior year adjustments	(506)	5		9
Share options exercised	(15)	(40)		(84)
Overseas profits taxed at different rates	292	251		179
Change in rate of deferred tax	(703)	0		(100)
Total tax	£ (2,496)	£ (3,762)	[1]	£ (4,336)
Standard rate of corporation tax	19.00%	19.17%
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Income tax - Narrative (Details

Income tax - Narrative (Details) - GBP (£)	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017
Disclosure of income tax [Line Items]
Current tax liabilities	£ 0	£ 0	£ 0
Operating loss carryforward, maximum annual limit	£ 5,000,000
Finance (No 2) Act 2015
Disclosure of income tax [Line Items]
Corporate income tax rate	20.00%
Finance (No 2) Act 2015 | April 1, 2017
Disclosure of income tax [Line Items]
Corporate income tax rate	19.00%
Finance (No 2) Act 2015 | April 1, 2020
Disclosure of income tax [Line Items]
Corporate income tax rate	18.00%
Finance Act 2016 | April 1, 2020
Disclosure of income tax [Line Items]
Corporate income tax rate	17.00%

Earnings _ (loss) per share (De

Earnings / (loss) per share (Details) - GBP (£) £ / shares in Units, £ in Thousands, shares in Thousands	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018		Jan. 31, 2017
Earnings per share [abstract]
Profit / (loss) for the year	£ 7,527	£ (20,190)	[1]	£ (21,371)
Weighted average number of ordinary shares for basic earnings / (loss) earnings per share (in shares)	85,702	65,434		61,549
Effect of dilutive potential ordinary shares (share options and warrants) (in shares)	442	0		0
Weighted average number of ordinary shares for diluted earnings per share (in shares)	86,144	65,434		61,549
Basic earnings / (loss) per ordinary share from operations (in pounds per share)	£ 0.09	£ (0.31)		£ (0.35)
Diluted earnings / (loss) per ordinary share from operations (in pounds per share)	£ 0.09	£ (0.31)		£ (0.35)
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Earnings _ (loss) per share - T

Earnings / (loss) per share - Textual (Details)	12 Months Ended
	Jan. 31, 2019shares	Jan. 31, 2018shares	Jan. 31, 2017shares
Disclosure of analysis of other comprehensive income by item [line items]
Number of share options outstanding in share-based payment arrangement	9,168,396	8,577,236	7,383,401
Number of other equity instruments outstanding in share-based payment arrangement	814,256	275,877	0
Weighted average number of shares outstanding	85,702,000	65,434,000	61,549,000
Shares excluded from computation of earnings per share	8,094,227
Restricted Stock Units (RSUs)
Disclosure of analysis of other comprehensive income by item [line items]
Number of other equity instruments outstanding in share-based payment arrangement	814,256

Goodwill (Details)

Goodwill (Details) - GBP (£) £ in Thousands		Dec. 23, 2017	Jan. 31, 2019	Jan. 31, 2018
Disclosure of reconciliation of changes in goodwill [line items]
Goodwill, beginning	[1]		£ 2,478
Goodwill, ending			1,814	£ 2,478	[1]
Goodwill
Disclosure of reconciliation of changes in goodwill [line items]
Goodwill, beginning			2,478	664
Goodwill, ending			1,814	2,478
Cost | Goodwill
Disclosure of reconciliation of changes in goodwill [line items]
Goodwill, beginning			2,478	664
Additions				1,814
Goodwill, ending			2,478	2,478
Accumulated impairment | Goodwill
Disclosure of reconciliation of changes in goodwill [line items]
Goodwill, beginning			0	0
Impairment			(664)
Goodwill, ending			(664)	0
Discuva Limited
Disclosure of reconciliation of changes in goodwill [line items]
Percentage of voting equity interests acquired		100.00%
Discuva Limited | Goodwill
Disclosure of reconciliation of changes in goodwill [line items]
Goodwill, beginning			1,814	0
Goodwill, ending			1,814	1,814
Discuva Limited | Cost | Goodwill
Disclosure of reconciliation of changes in goodwill [line items]
Goodwill, beginning			1,814	0
Additions		£ 1,800		1,814
Goodwill, ending			1,814	1,814
Discuva Limited | Accumulated impairment | Goodwill
Disclosure of reconciliation of changes in goodwill [line items]
Goodwill, beginning			0	0
Impairment			0
Goodwill, ending			0	0
MuOx Limited | Goodwill
Disclosure of reconciliation of changes in goodwill [line items]
Goodwill, beginning			664	664
Goodwill, ending			0	664
MuOx Limited | Cost | Goodwill
Disclosure of reconciliation of changes in goodwill [line items]
Goodwill, beginning			664	664
Additions				0
Goodwill, ending			664	664
MuOx Limited | Accumulated impairment | Goodwill
Disclosure of reconciliation of changes in goodwill [line items]
Goodwill, beginning			0	0
Impairment			(664)
Goodwill, ending			£ (664)	£ 0
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Intangible assets - Disclosure

Intangible assets - Disclosure of reconciliation of changes in intangible assets (Details) - GBP (£) £ in Thousands	12 Months Ended
	Jan. 31, 2019		Jan. 31, 2018		Jan. 31, 2017
Reconciliation of changes in intangible assets other than goodwill [abstract]
Intangible assets, beginning balance	£ 14,785	[1]	£ 3,470
Accumulated amortization	(829)		(106)	[1]	£ (10)
Intangible assets, ending balance	10,604		14,785	[1]	3,470
Cost
Reconciliation of changes in intangible assets other than goodwill [abstract]
Intangible assets, beginning balance	14,924		4,905
Acquisition of subsidiary			11,338
Additions	6		119
Disposals	(49)		(1,438)
Intangible assets, ending balance	14,881		14,924		4,905
Accumulated depreciation
Reconciliation of changes in intangible assets other than goodwill [abstract]
Intangible assets, beginning balance	(139)		(1,435)
Accumulated amortization	(829)		(106)
Impairment	(3,321)
Disposals	12		1,402
Intangible assets, ending balance	(4,277)		(139)		(1,435)
Option over non-financial assets
Reconciliation of changes in intangible assets other than goodwill [abstract]
Intangible assets, beginning balance	664		0
Intangible assets, ending balance	619		664		0
Option over non-financial assets | Cost
Reconciliation of changes in intangible assets other than goodwill [abstract]
Intangible assets, beginning balance	668		0
Acquisition of subsidiary			668
Additions	0		0
Disposals	0		0
Intangible assets, ending balance	668		668		0
Option over non-financial assets | Accumulated depreciation
Reconciliation of changes in intangible assets other than goodwill [abstract]
Intangible assets, beginning balance	(4)		0
Accumulated amortization	(45)		(4)
Impairment	0
Disposals	0		0
Intangible assets, ending balance	(49)		(4)		0
Other patents and licenses
Reconciliation of changes in intangible assets other than goodwill [abstract]
Intangible assets, beginning balance	209		149
Intangible assets, ending balance	133		209		149
Other patents and licenses | Cost
Reconciliation of changes in intangible assets other than goodwill [abstract]
Intangible assets, beginning balance	265		204
Acquisition of subsidiary			0
Additions	6		119
Disposals	(49)		(58)
Intangible assets, ending balance	222		265		204
Other patents and licenses | Accumulated depreciation
Reconciliation of changes in intangible assets other than goodwill [abstract]
Intangible assets, beginning balance	(56)		(55)
Accumulated amortization	(45)		(23)
Impairment	0
Disposals	12		22
Intangible assets, ending balance	(89)		(56)		(55)
Iminosugar
Reconciliation of changes in intangible assets other than goodwill [abstract]
Intangible assets, beginning balance	0		0
Intangible assets, ending balance			0		0
Iminosugar | Cost
Reconciliation of changes in intangible assets other than goodwill [abstract]
Intangible assets, beginning balance	0		1,380
Acquisition of subsidiary			0
Additions			0
Disposals			(1,380)
Intangible assets, ending balance			0		1,380
Iminosugar | Accumulated depreciation
Reconciliation of changes in intangible assets other than goodwill [abstract]
Intangible assets, beginning balance	0		(1,380)
Accumulated amortization			0
Disposals			1,380
Intangible assets, ending balance			0		(1,380)
Utrophin
Reconciliation of changes in intangible assets other than goodwill [abstract]
Intangible assets, beginning balance	3,321		3,321
Intangible assets, ending balance	0		3,321		3,321
Utrophin | Cost
Reconciliation of changes in intangible assets other than goodwill [abstract]
Intangible assets, beginning balance	3,321		3,321
Acquisition of subsidiary			0
Additions	0		0
Disposals	0		0
Intangible assets, ending balance	3,321		3,321		3,321
Utrophin | Accumulated depreciation
Reconciliation of changes in intangible assets other than goodwill [abstract]
Intangible assets, beginning balance	0		0
Accumulated amortization	0		0
Impairment	(3,321)
Disposals	0		0
Intangible assets, ending balance	(3,321)		0		0
Discuva Limited
Reconciliation of changes in intangible assets other than goodwill [abstract]
Intangible assets, beginning balance	10,591		0
Intangible assets, ending balance	9,852		10,591		0
Discuva Limited | Cost
Reconciliation of changes in intangible assets other than goodwill [abstract]
Intangible assets, beginning balance	10,670		0
Acquisition of subsidiary			10,670
Additions	0		0
Disposals	0		0
Intangible assets, ending balance	10,670		10,670		0
Discuva Limited | Accumulated depreciation
Reconciliation of changes in intangible assets other than goodwill [abstract]
Intangible assets, beginning balance	(79)		0
Accumulated amortization	(739)		(79)
Impairment	0
Disposals	0		0
Intangible assets, ending balance	£ (818)		£ (79)		£ 0
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Intangible assets - Narrative (

Intangible assets - Narrative (Details) - GBP (£) £ in Thousands	1 Months Ended	12 Months Ended
	Jun. 30, 2018	Jan. 31, 2019	Jan. 31, 2018	[1]	Jan. 31, 2017
Disclosure of detailed information about intangible assets [line items]
Impairment of goodwill and intangible assets		£ 3,985	£ 0		£ 0
MuOx Limited
Disclosure of detailed information about intangible assets [line items]
Impairment of goodwill and intangible assets	£ 4,000
Intangible asset | MuOx Limited
Disclosure of detailed information about intangible assets [line items]
Impairment of goodwill and intangible assets	3,300
Goodwill | MuOx Limited
Disclosure of detailed information about intangible assets [line items]
Impairment of goodwill and intangible assets	£ 700
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Property, plant and equipment_2

Property, plant and equipment (Details) - GBP (£) £ in Thousands	12 Months Ended
	Jan. 31, 2019		Jan. 31, 2018
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	£ 809	[1]	£ 116
Property, plant and equipment	616		809	[1]
Cost
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	1,125		312
Acquisition of subsidiary			329
Additions	119		513
Disposals	(74)		(23)
Revaluation	(5)
Property, plant and equipment	1,175		1,125
Accumulated depreciation
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	(316)		(196)
Charge for the year	(309)		(140)
Disposals	68		19
Revaluation	(2)
Property, plant and equipment	(559)		(316)
Leasehold improvements
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	309		0
Property, plant and equipment	275		309
Leasehold improvements | Cost
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	340		9
Acquisition of subsidiary			0
Additions	0		340
Disposals	0		(9)
Revaluation	0
Property, plant and equipment	340		340
Leasehold improvements | Accumulated depreciation
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	(31)		(9)
Charge for the year	(34)		(31)
Disposals	0		9
Revaluation	0
Property, plant and equipment	(65)		(31)
Laboratory equipment
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	263		2
Property, plant and equipment	168		263
Laboratory equipment | Cost
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	299		19
Acquisition of subsidiary			280
Additions	62		0
Disposals	(22)		0
Revaluation	0
Property, plant and equipment	339		299
Laboratory equipment | Accumulated depreciation
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	(36)		(17)
Charge for the year	(156)		(19)
Disposals	21		0
Revaluation	0
Property, plant and equipment	(171)		(36)
Office and IT equipment
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	237		114
Property, plant and equipment	173		237
Office and IT equipment | Cost
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	486		284
Acquisition of subsidiary			49
Additions	57		173
Disposals	(52)		(14)
Revaluation	(5)
Property, plant and equipment	496		486
Office and IT equipment | Accumulated depreciation
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment	(249)		(170)
Charge for the year	(119)		(90)
Disposals	47		10
Revaluation	(2)
Property, plant and equipment	£ (323)		£ (249)
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Trade and other receivables (De

Trade and other receivables (Details) - GBP (£) £ in Thousands	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018
Trade and other receivables [abstract]
Trade receivables	£ 1,656	£ 0
Other receivables	3,847	3,600
Prepayments	7,433	6,498
Accrued income	611	1,036
Trade and other receivables	13,547	£ 11,134
Prepayments relating to research and development expenditure	£ 6,800
Research and development, stage of completion, percentage increase	5.00%
Research and development, stage of completion, increase, expense	£ 1,000
Research and development, stage of completion, percentage decrease	5.00%
Research and development, stage of completion, decrease, expense	£ 1,200

Trade and other payables (Detai

Trade and other payables (Details) - GBP (£) £ in Thousands	Jan. 31, 2019	Jan. 31, 2018
Trade and other payables [abstract]
Trade payables	£ 4,422	£ 4,414
Other taxes and social security	190	164
Accruals	4,095	4,078
Other creditors	158	276
Trade and other current payables	8,865	£ 8,932	[1]
Accruals and deferred income classified as current, research and development expenditure	£ (1,900)
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Deferred revenue and income - D

Deferred revenue and income - Detailed disclosure about deferred income (Details) - GBP (£) £ in Thousands	Jan. 31, 2019	Jan. 31, 2018
Accruals and deferred income [abstract]
Deferred revenue	£ 499	£ 11,478
Deferred other operating income	2,875	2,356
Deferred revenue and income	3,374	13,834	[1]
Deferred revenue	831	27,270
Deferred revenue	831	27,270	[1]
Total deferred revenue	1,330	38,748
Total deferred other operating income	£ 2,875	£ 2,356
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Deferred revenue and income - N

Deferred revenue and income - Narrative (Details) £ in Millions	12 Months Ended
	Jan. 31, 2019GBP (£)
Accruals and deferred income [abstract]
Deferred revenue, recognized	£ (37.4)

Contingent consideration (Detai

Contingent consideration (Details) - GBP (£) £ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2017	Jan. 31, 2019	Jan. 31, 2018		Jan. 31, 2017
Disclosure of detailed information about business combination [line items]
Loss on recognition of contingent consideration payable		£ 754	£ 0	[1]	£ 0
Contingent consideration		(629)	0	[1]
Contingent consideration paid		192	£ 0		£ 0
Discuva Limited
Disclosure of detailed information about business combination [line items]
Loss on recognition of contingent consideration payable	£ 800
Contingent consideration		(600)
Contingent consideration paid		£ (200)
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Financial liabilities on fund_3

Financial liabilities on funding arrangements - Narrative (Details) - GBP (£) £ in Thousands	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017
Disclosure of financial liabilities [line items]
Estimated financial liabilities on funding arrangements	£ 0	£ 3,090	£ 5,919
Bottom of range
Disclosure of financial liabilities [line items]
Discount factors	16.00%
Top of range
Disclosure of financial liabilities [line items]
Discount factors	18.00%

Financial liabilities on fund_4

Financial liabilities on funding arrangements - Reconciliation of financial liabilities on funding arrangements (Details) - GBP (£) £ in Thousands	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018
Financial Liabilities At Amortised Cost [Abstract]
At February 1	£ 3,090	£ 5,919
Unwinding of discount factor	233	754
Derecognition of financial liabilities – finance income	0	(3,085)
Remeasurement of financial liabilities on funding arrangements - (finance income) / finance cost	(2,784)	410
Net finance income on funding arrangements accounting for as financial liabilities	(2,551)	(1,921)
Remeasurement or derecognition of financial liabilities – other operating income	(539)	(908)
At January 31	£ 0	£ 3,090

Financial instruments - Disclos

Financial instruments - Disclosure of detailed information about financial instruments (Details) - GBP (£) £ in Thousands	Jan. 31, 2019	Jan. 31, 2018
Disclosure of financial liabilities [line items]
Contingent consideration	£ 629	£ 0	[1]
Financial liabilities measured at amortized cost
Disclosure of financial liabilities [line items]
Financial liabilities	8,865	12,022
Financial assets at amortized cost
Disclosure of financial assets [line items]
Financial assets	32,361	23,702
Trade and other payables | Financial liabilities measured at amortized cost
Disclosure of financial liabilities [line items]
Financial liabilities	8,865	8,932
Financial liabilities on funding arrangements | Financial liabilities measured at amortized cost
Disclosure of financial liabilities [line items]
Financial liabilities	0	3,090
Trade and other receivables | Financial assets at amortized cost
Disclosure of financial assets [line items]
Financial assets	5,503	3,600
Cash and cash equivalents | Financial assets at amortized cost
Disclosure of financial assets [line items]
Financial assets	£ 26,858	£ 20,102
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Financial instruments - Foreign

Financial instruments - Foreign currency and interest rate risk (Details) - GBP (£) £ in Thousands	Jan. 31, 2019	Jan. 31, 2018
Foreign currency risk
Disclosure of nature and extent of risks arising from financial instruments [line items]
Risk exposure	£ 26,858	£ 20,102
Interest rate risk
Disclosure of nature and extent of risks arising from financial instruments [line items]
Risk exposure	26,858	20,102
Pounds Sterling | Foreign currency risk
Disclosure of nature and extent of risks arising from financial instruments [line items]
Risk exposure	3,363	5,535
US Dollar | Foreign currency risk
Disclosure of nature and extent of risks arising from financial instruments [line items]
Risk exposure	£ 23,495	£ 14,567

Financial instruments - Narrati

Financial instruments - Narrative (Details) - GBP (£) £ in Thousands	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018
Financial Instruments [Abstract]
Interest rate fee percentage	0.02%	0.02%
Average cash balance	£ 23,500	£ 24,100
Trade receivables	£ 1,656	£ 0

Financial instruments - Interes

Financial instruments - Interest rate sensitivity analysis (Details) - GBP (£) £ in Thousands	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017
Disclosure of nature and extent of risks arising from financial instruments [line items]
Interest received, Actual	£ 4	£ 11	£ 8
Interest rate risk
Disclosure of nature and extent of risks arising from financial instruments [line items]
Interest rate, Actual	2.00%	2.00%
Interest received, Actual	£ 4	£ 5
Interest rate, 1% increase	102.00%	102.00%
Interest received, 1% increase	£ 239	£ 246

Provisions for other liabilit_3

Provisions for other liabilities and charges and contingent liabilities - Disclosure of contingent liabilities (Details) - GBP (£) £ in Thousands	12 Months Ended
	Jan. 31, 2019		Jan. 31, 2018
Disclosure of other provisions [line items]
Beginning balance	£ 1,641	[1]	£ 85
Additions	19		1,641
Unwinding of the discount factor	191
Used during the year			(85)
Ending balance	1,851		1,641	[1]
Assumed contingent liabilities
Disclosure of other provisions [line items]
Beginning balance	1,466		0
Additions	0		1,466
Unwinding of the discount factor	191
Used during the year			0
Ending balance	1,657		1,466
Dilapidations
Disclosure of other provisions [line items]
Beginning balance	150		85
Additions	0		150
Unwinding of the discount factor	0
Used during the year			(85)
Ending balance	150		150
Royalties
Disclosure of other provisions [line items]
Beginning balance	25		0
Additions	19		25
Unwinding of the discount factor	0
Used during the year			0
Ending balance	£ 44		£ 25
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Provisions for other liabilit_4

Provisions for other liabilities and charges and contingent liabilities - Narrative (Details) - GBP (£) £ in Thousands	Jan. 31, 2019	Jan. 31, 2018	Dec. 31, 2017
The School Of Pharmacy, University Of London
Disclosure of other provisions [line items]
Financial liabilities	£ 1,000
Financial liabilities, initial payment	40
Discuva Limited
Disclosure of other provisions [line items]
Discount rate applied to cash flow projections			13.00%
Contingent liabilities recognised as of acquisition date	£ 1,658	£ 1,500
Wellcome Trust
Disclosure of other provisions [line items]
Discount rate applied to cash flow projections	0.80%

Provisions for other liabilit_5

Provisions for other liabilities and charges and contingent liabilities - Disclosure of contingent liabilities in business combination (Details) - Discuva Limited - GBP (£) £ in Thousands	Jan. 31, 2019	Jan. 31, 2018
Disclosure of contingent liabilities [line items]
Estimated assumed contingent liabilities	£ 1,658	£ 1,500
1% lower discount rate	1,770
1% higher discount rate	1,560
10% lower probability of success	1,366
10% higher probability of success	£ 1,927

Deferred tax liability - Narrat

Deferred tax liability - Narrative (Details) - GBP (£) £ in Thousands	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018
Disclosure of income tax [Line Items]
Deferred tax liability, release relating to intangible asset impairment	£ 704	£ 0
Unrecognized deferred tax asset in relation to trading losses carried forward	12,400	11,944
Unrecognized deferred tax asset in relation to provisions	26	26
Unrecognized deferred tax asset in respect of accelerated capital allowances	32	588
Deferred tax liability in respect of accelerated capital allowances	43	£ 71
MuOx Limited
Disclosure of income tax [Line Items]
Deferred tax liability, release relating to intangible asset impairment	£ (600)

Deferred tax liability - Detail

Deferred tax liability - Detailed disclosure about deferred tax liability (Details) - GBP (£) £ in Thousands	12 Months Ended
	Jan. 31, 2019		Jan. 31, 2018
Deferred tax assets and liabilities [abstract]
At February 1	£ 2,379	[1]	£ 565
Release of temporary difference relating to the intangible asset	(704)		0
Acquisition of subsidiary	0		1,814
At January 31	£ 1,675		£ 2,379	[1]
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Share capital - Disclosure of s

Share capital - Disclosure of share capital (Details) - GBP (£) £ / shares in Units, £ in Thousands	Jan. 31, 2019	Jan. 09, 2019	Mar. 29, 2018	Jan. 31, 2018		Jan. 31, 2017
Disclosure of classes of share capital [line items]
Alloted, called up and fully paid	£ 1,604			£ 736	[1]
Ordinary shares
Disclosure of classes of share capital [line items]
Alloted, called up and fully paid	£ 1,604		£ 15,000	£ 736
Number of shares issued and fully paid (in shares)	160,389,881	78,125,000	8,333,333	73,563,624		61,841,566
Par value per share (in pounds per share)	£ 0.01		£ 1.80	£ 0.01
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Share capital - Change in ordin

Share capital - Change in ordinary Shares (Details) - GBP (£) £ in Thousands		12 Months Ended
		Jan. 31, 2019	Jan. 31, 2018		Jan. 31, 2017
Number of shares
Share options exercised (in shares)		92,047	348,536
Disclosure of classes of share capital [abstract]
Share capital, beginning balance	[1]	£ 736
New share capital issued (net of transaction costs)		34,648	£ 14,931
Issue of Ordinary Shares as consideration for a business combination			5,000
New share capital issued from exercise of warrants			10		£ 107
Share options exercised		102	392		£ 283
Share capital, ending balance		£ 1,604	£ 736	[1]
Ordinary shares
Number of shares
Number of shares issued and fully paid, beginning balance (in shares)		73,563,624	61,841,566
New share capital issued (net of transaction costs) (in shares)		86,458,333	8,389,250
Issue of Ordinary Shares as consideration for a business combination (in shares)			2,934,272
New share capital issued from exercise of warrants (in shares)			50,000
Share options exercised (in shares)		367,924	348,536
Number of shares issued and fully paid, ending balance (in shares)		160,389,881	73,563,624		61,841,566
Disclosure of classes of share capital [abstract]
Share capital, beginning balance		£ 736
Share capital, ending balance		1,604	£ 736
Share capital
Disclosure of classes of share capital [abstract]
New share capital issued (net of transaction costs)		864	84
Issue of Ordinary Shares as consideration for a business combination			30
New share capital issued from exercise of warrants			1		£ 2
Share options exercised		4	3		3
Share capital | Ordinary shares
Disclosure of classes of share capital [abstract]
Share capital, beginning balance		736	618
New share capital issued (net of transaction costs)		864	84
Issue of Ordinary Shares as consideration for a business combination			30
New share capital issued from exercise of warrants			1
Share options exercised		4	3
Share capital, ending balance		1,604	736		618
Share premium
Disclosure of classes of share capital [abstract]
New share capital issued (net of transaction costs)		33,784	14,847
New share capital issued from exercise of warrants			9		105
Share options exercised		98	389		280
Share premium | Ordinary shares
Disclosure of classes of share capital [abstract]
Share capital, beginning balance		60,237	46,420
New share capital issued (net of transaction costs)		32,471	13,419
Issue of Ordinary Shares as consideration for a business combination			0
New share capital issued from exercise of warrants			9
Share options exercised		98	389
Share capital, ending balance		92,806	60,237		46,420
Total consideration | Ordinary shares
Disclosure of classes of share capital [abstract]
Share capital, beginning balance		60,973	47,038
New share capital issued (net of transaction costs)		33,335	13,503
Issue of Ordinary Shares as consideration for a business combination			30
New share capital issued from exercise of warrants			10
Share options exercised		102	392
Share capital, ending balance		£ 94,410	£ 60,973		£ 47,038
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Share capital - Narrative (Deta

Share capital - Narrative (Details) £ / shares in Units, $ / shares in Units, $ in Millions	Jan. 09, 2019GBP (£)	Mar. 29, 2018GBP (£)£ / sharesshares	Jan. 31, 2019GBP (£)£ / sharesshares	Jan. 31, 2018GBP (£)£ / sharesshares		Jan. 31, 2017GBP (£)shares	Jan. 09, 2019USD ($)$ / sharesshares	Jan. 09, 2019GBP (£)shares
Disclosure of classes of share capital [line items]
Share capital			£ 1,604,000	£ 736,000	[1]
Proceeds from exercise of share options			102,000	392,000	[1]	£ 283,000
Dividends declared			0	0
Dividends paid			£ 0	£ 0
Ordinary shares
Disclosure of classes of share capital [line items]
Number of shares issued and fully paid (in shares) | shares		8,333,333	160,389,881	73,563,624		61,841,566	78,125,000	78,125,000
Par value per share (in pounds per share) | £ / shares		£ 1.80	£ 0.01	£ 0.01
Share capital		£ 15,000,000	£ 1,604,000	£ 736,000
Share issue related cost		£ 900,000
American Depository Shares
Disclosure of classes of share capital [line items]
Number of shares issued and fully paid (in shares) | shares							15,625,000	15,625,000
Par value per share (in pounds per share) | $ / shares							$ 1.60
Share capital							$ 25	£ 19,600,000
Share issue related cost	£ 400,000
Number of ordinary shares | shares							5	5
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Share capital - Number of optio

Share capital - Number of options exercised (Details) - shares	Oct. 24, 2018	Jul. 18, 2018	Apr. 23, 2018	Apr. 18, 2018	Mar. 16, 2018	Jan. 31, 2019	Jan. 31, 2018
Disclosure of classes of share capital [line items]
Share options exercised (in shares)						92,047	348,536
Share Options and Restricted Stock Units (RSUs)
Disclosure of classes of share capital [line items]
Share options exercised (in shares)	138,886	136,991	48,981	38,850	4,216	367,924

Share option scheme and restr_3

Share option scheme and restricted stock units - Outstanding share options (Details)	Jan. 31, 2019GBP (£)shares	Jan. 31, 2018GBP (£)shares	Jan. 31, 2017GBP (£)shares
Share Options
Number of shares (in shares)	9,168,396	8,577,236	7,383,401
RSU's
Exercise price (in Pounds per share) | £	£ 0.01	£ 0.01	£ 0
Number of shares (in shares)	814,256	275,877	0
Approved EMI scheme
Share Options
Number of shares (in shares)	408,956
Unapproved scheme
Share Options
Number of shares (in shares)	8,759,440
April 7, 2011 | Approved EMI scheme
Share Options
Exercise price of outstanding share options (in Pounds per share) | £	£ 0.65
Number of shares (in shares)	5,873
May 10, 2012 | Approved EMI scheme
Share Options
Exercise price of outstanding share options (in Pounds per share) | £	£ 0.60
Number of shares (in shares)	150,046
December 24, 2012 | Approved EMI scheme
Share Options
Exercise price of outstanding share options (in Pounds per share) | £	£ 0.85
Number of shares (in shares)	21,500
December 18, 2013 | Unapproved scheme
Share Options
Exercise price of outstanding share options (in Pounds per share) | £	£ 0.20
Number of shares (in shares)	76,364
January 31, 2013 | Approved EMI scheme
Share Options
Exercise price of outstanding share options (in Pounds per share) | £	£ 0.20
Number of shares (in shares)	72,973
July 15, 2014 | Approved EMI scheme
Share Options
Exercise price of outstanding share options (in Pounds per share) | £	£ 1.26
Number of shares (in shares)	100,000
January 21, 2015 | Unapproved scheme
Share Options
Exercise price of outstanding share options (in Pounds per share) | £	£ 1.23
Number of shares (in shares)	75,000
June 23, 2016 | Approved EMI scheme
Share Options
Exercise price of outstanding share options (in Pounds per share) | £	£ 1.05
Number of shares (in shares)	58,564
June 27, 2017 | Unapproved scheme
Share Options
Exercise price of outstanding share options (in Pounds per share) | £	£ 1.80
Number of shares (in shares)	5,989
July 18, 2017 | Unapproved scheme
RSU's
Exercise price (in Pounds per share) | £	£ 0.01
Number of shares (in shares)	121,950
October 24, 2017 | Unapproved scheme
RSU's
Exercise price (in Pounds per share) | £	£ 0.01
Number of shares (in shares)	692,306
April 20, 2018 | Unapproved scheme
Share Options
Exercise price of outstanding share options (in Pounds per share) | £	£ 2.05
Number of shares (in shares)	9,514
Tranche one | July 15, 2014 | Unapproved scheme
Share Options
Exercise price of outstanding share options (in Pounds per share) | £	£ 1.26
Number of shares (in shares)	175,000
Tranche one | June 23, 2016 | Unapproved scheme
Share Options
Exercise price of outstanding share options (in Pounds per share) | £	£ 0.01
Number of shares (in shares)	110,576
Tranche one | July 18, 2017 | Unapproved scheme
Share Options
Exercise price of outstanding share options (in Pounds per share) | £	£ 1.83
Number of shares (in shares)	11,825
Tranche one | October 24, 2017 | Unapproved scheme
Share Options
Exercise price of outstanding share options (in Pounds per share) | £	£ 1.80
Number of shares (in shares)	12,264
Tranche one | April 20, 2018 | Unapproved scheme
Share Options
Exercise price of outstanding share options (in Pounds per share) | £	£ 2.05
Number of shares (in shares)	9,514
Tranche one | October 19, 2018 | Unapproved scheme
Share Options
Exercise price of outstanding share options (in Pounds per share) | £	£ 0.30
Number of shares (in shares)	4,324,198
Tranche two | July 15, 2014 | Unapproved scheme
Share Options
Exercise price of outstanding share options (in Pounds per share) | £	£ 0.80
Number of shares (in shares)	100,000
Tranche two | October 19, 2018 | Unapproved scheme
Share Options
Exercise price of outstanding share options (in Pounds per share) | £	£ 0.30
Number of shares (in shares)	3,814,970
Tranche three | June 23, 2016 | Unapproved scheme
Share Options
Exercise price of outstanding share options (in Pounds per share) | £	£ 1.05
Number of shares (in shares)	43,740

Share option scheme and restr_4

Share option scheme and restricted stock units - Movement in options (Details)	12 Months Ended
	Jan. 31, 2019GBP (£)shares	Jan. 31, 2018GBP (£)shares
Share Options
Outstanding at February 1, (in Pounds per share) | £	£ 1.43	£ 1.17
Granted during the year (in Pounds per share) | £	0.76	1.83
Lapsed / surrendered during the year (in Pounds per share) | £	1.52	0.99
Exercised during the year (in Pounds per share) | £	1.08	1.13
Outstanding at January 31, (in Pounds per share) | £	£ 0.35	£ 1.43
Outstanding at February 1, (in shares) | shares	8,577,236	7,383,401
Granted during the year (in shares) | shares	13,081,048	2,972,903
Lapsed / surrendered during the year (in shares) | shares	(12,397,841)	(1,430,532)
Exercised during the year (in shares) | shares	(92,047)	(348,536)
Outstanding at January 31, (in shares) | shares	9,168,396	8,577,236
RSU's
Outstanding at February 1, (in Pounds per share) | £	£ 0.01	£ 0
Granted during the year (in Pounds per share) | £	0.01	0.01
Exercised during the year (in Pounds per share) | £	0.01	0
Outstanding at January 31, (in Pounds per share) | £	£ 0.01	£ 0.01
Outstanding at February 1, (in shares) | shares	275,877	0
Granted during the year (in shares) | shares	814,256	275,877
Exercised during the year (in shares) | shares	(275,877)	0
Outstanding at January 31, (in shares) | shares	814,256	275,877

Share option scheme and restr_5

Share option scheme and restricted stock units - Narrative (Details)	12 Months Ended
	Jan. 31, 2019GBP (£)yearshares	Jan. 31, 2018GBP (£)yearshares	Jan. 31, 2017GBP (£)
Disclosure of terms and conditions of share-based payment arrangement [line items]
Share options voluntarily surrendered | shares	12,397,841	1,430,532
Share-based payment | £	£ 4,743,000	£ 1,607,000	£ 1,379,000
Number of share options exercisable in share-based payment arrangement (in shares) | shares	1,029,228	2,042,546
Weighted average exercise price of share options exercisable in share-based payment arrangement (in pounds per share) | £	£ 0.82	£ 1
Number of outstanding options (in Pounds per share) | £	£ 0.35	£ 1.43	£ 1.17
Share options, remaining contractual life | year	9.2	7.9
Number of RSUs exercisable in share-based payment arrangement (in shares) | shares	0	0
Weighted average exercise price of RSUs exercisable in share-based payment arrangement (in Pounds per share) | £	£ 0.01	£ 0.01
RSUs, remaining contractual life | year	1.8	0.9
Bottom of range
Disclosure of terms and conditions of share-based payment arrangement [line items]
Expected volatility, share options granted	39.00%
Expected volatility, RSUs granted	50.00%
Top of range
Disclosure of terms and conditions of share-based payment arrangement [line items]
Expected volatility, share options granted	134.00%
Expected volatility, RSUs granted	57.00%
Share Options, Voluntarily Surrendered
Disclosure of terms and conditions of share-based payment arrangement [line items]
Share options voluntarily surrendered | shares	7,172,054

Share option scheme and restr_6

Share option scheme and restricted stock units - Fair value per award granted (Details)	12 Months Ended
	Jan. 31, 2019GBP (£)yearshares	Jan. 31, 2018GBP (£)shares	Jan. 31, 2017GBP (£)shares
Share Options
Number of shares (in shares) | shares	9,168,396	8,577,236	7,383,401
RSU's
Number of shares (in shares) | shares	814,256	275,877	0
Exercise price (in Pounds per share)	£ 0.01	£ 0.01	£ 0
Share price at grant date (in Pounds per share)	£ 0.01	£ 0.01
Approved EMI scheme
Share Options
Number of shares (in shares) | shares	408,956
Unapproved scheme
Share Options
Number of shares (in shares) | shares	8,759,440
April 7, 2011 | Approved EMI scheme
Share Options
Number of shares (in shares) | shares	5,873
Exercise price of outstanding share options (in Pounds per share)	£ 0.65
Share price at grant date	0.65
Fair value per option (in Pounds per share)	£ 0.47
Award life (years) | year	5
Risk free rate	2.70%
May 10, 2012 | Approved EMI scheme
Share Options
Number of shares (in shares) | shares	150,046
Exercise price of outstanding share options (in Pounds per share)	£ 0.60
Share price at grant date	0.52
Fair value per option (in Pounds per share)	£ 0.24
Award life (years) | year	5
Risk free rate	1.00%
December 24, 2012 | Approved EMI scheme
Share Options
Number of shares (in shares) | shares	21,500
Exercise price of outstanding share options (in Pounds per share)	£ 0.85
Share price at grant date	0.85
Fair value per option (in Pounds per share)	£ 0.59
Award life (years) | year	5
Risk free rate	0.90%
January 31, 2013 | Approved EMI scheme
Share Options
Number of shares (in shares) | shares	72,973
Exercise price of outstanding share options (in Pounds per share)	£ 0.20
Share price at grant date	0.94
Fair value per option (in Pounds per share)	£ 0.74
Award life (years) | year	5
Risk free rate	1.00%
December 18, 2013 | Unapproved scheme
Share Options
Number of shares (in shares) | shares	76,364
Exercise price of outstanding share options (in Pounds per share)	£ 0.20
Share price at grant date	1.85
Fair value per option (in Pounds per share)	£ 1.65
Award life (years) | year	5
Risk free rate	1.00%
July 15, 2014 | Approved EMI scheme
Share Options
Number of shares (in shares) | shares	100,000
Exercise price of outstanding share options (in Pounds per share)	£ 1.26
Share price at grant date	1.26
Fair value per option (in Pounds per share)	£ 0.65
Award life (years) | year	3
Risk free rate	1.30%
January 21, 2015 | Unapproved scheme
Share Options
Number of shares (in shares) | shares	75,000
Exercise price of outstanding share options (in Pounds per share)	£ 1.23
Share price at grant date	1.22
Fair value per option (in Pounds per share)	£ 0.64
Award life (years) | year	3
Risk free rate	0.60%
June 23, 2016 | Approved EMI scheme
Share Options
Number of shares (in shares) | shares	58,564
Exercise price of outstanding share options (in Pounds per share)	£ 1.05
Share price at grant date	1.05
Fair value per option (in Pounds per share)	£ 0.25
Award life (years) | year	3
Risk free rate	0.30%
June 27, 2017 | Unapproved scheme
Share Options
Number of shares (in shares) | shares	5,989
Exercise price of outstanding share options (in Pounds per share)	£ 1.80
Share price at grant date	1.78
Fair value per option (in Pounds per share)	£ 0.64
Award life (years) | year	3
Risk free rate	0.23%
July 18, 2017 | Unapproved scheme
RSU's
Number of shares (in shares) | shares	121,950
Exercise price (in Pounds per share)	£ 0.01
Share price at grant date (in Pounds per share)	2.05
Fair value per option (in Pounds per share)	£ 2.04
Award life (years) | year	1
Risk free rate	0.70%
October 24, 2017 | Unapproved scheme
RSU's
Number of shares (in shares) | shares	692,306
Exercise price (in Pounds per share)	£ 0.01
Share price at grant date (in Pounds per share)	0.26
Fair value per option (in Pounds per share)	£ 0.25
Award life (years) | year	1
Risk free rate	0.79%
April 20, 2018 | Unapproved scheme
Share Options
Number of shares (in shares) | shares	9,514
Exercise price of outstanding share options (in Pounds per share)	£ 2.05
Tranche one | July 15, 2014 | Unapproved scheme
Share Options
Number of shares (in shares) | shares	175,000
Exercise price of outstanding share options (in Pounds per share)	£ 1.26
Share price at grant date	1.26
Fair value per option (in Pounds per share)	£ 0.65
Award life (years) | year	3
Risk free rate	1.30%
Tranche one | June 23, 2016 | Unapproved scheme
Share Options
Number of shares (in shares) | shares	110,576
Exercise price of outstanding share options (in Pounds per share)	£ 0.01
Share price at grant date	1.05
Fair value per option (in Pounds per share)	£ 1.04
Award life (years) | year	0.50
Risk free rate	0.30%
Tranche one | July 18, 2017 | Unapproved scheme
Share Options
Number of shares (in shares) | shares	11,825
Exercise price of outstanding share options (in Pounds per share)	£ 1.83
Share price at grant date	1.83
Fair value per option (in Pounds per share)	£ 0.66
Award life (years) | year	3
Risk free rate	0.26%
Tranche one | October 24, 2017 | Unapproved scheme
Share Options
Number of shares (in shares) | shares	12,264
Exercise price of outstanding share options (in Pounds per share)	£ 1.80
Share price at grant date	1.70
Fair value per option (in Pounds per share)	£ 0.57
Award life (years) | year	3
Risk free rate	0.46%
Tranche one | April 20, 2018 | Unapproved scheme
Share Options
Number of shares (in shares) | shares	9,514
Exercise price of outstanding share options (in Pounds per share)	£ 2.05
Share price at grant date	2.05
Fair value per option (in Pounds per share)	£ 0.69
Award life (years) | year	3
Risk free rate	0.79%
Tranche one | October 19, 2018 | Unapproved scheme
Share Options
Number of shares (in shares) | shares	4,324,198
Exercise price of outstanding share options (in Pounds per share)	£ 0.30
Share price at grant date	0.30
Fair value per option (in Pounds per share)	£ 0.09
Award life (years) | year	3
Risk free rate	0.81%
Tranche two | July 15, 2014 | Unapproved scheme
Share Options
Number of shares (in shares) | shares	100,000
Exercise price of outstanding share options (in Pounds per share)	£ 0.80
Share price at grant date	0.81
Fair value per option (in Pounds per share)	£ 0.65
Award life (years) | year	1.90
Risk free rate	0.50%
Tranche two | October 19, 2018 | Unapproved scheme
Share Options
Number of shares (in shares) | shares	3,814,970
Exercise price of outstanding share options (in Pounds per share)	£ 0.30
Share price at grant date	0.30
Fair value per option (in Pounds per share)	£ 0.12
Award life (years) | year	3
Risk free rate	0.90%
Tranche three | June 23, 2016 | Unapproved scheme
Share Options
Number of shares (in shares) | shares	43,740
Exercise price of outstanding share options (in Pounds per share)	£ 1.05
Share price at grant date	1.05
Fair value per option (in Pounds per share)	£ 0.25
Award life (years) | year	3
Risk free rate	0.30%

Fixed assets purchase commitm_2

Fixed assets purchase commitments (Details) - GBP (£)	Jan. 31, 2019	Jan. 31, 2018
Fixed Assets Purchase Commitments [Abstract]
Contractual capital commitments	£ 0	£ 0

Leasing and other commitments_2

Leasing and other commitments (Details) - GBP (£) £ in Thousands	Jan. 31, 2019	Jan. 31, 2018
Disclosure of finance lease and operating lease by lessee [line items]
Minimum lease payments payable under non-cancellable operating lease	£ 1,080	£ 1,480
Not later than one year
Disclosure of finance lease and operating lease by lessee [line items]
Minimum lease payments payable under non-cancellable operating lease	357	337
Later than one year and not later than five years
Disclosure of finance lease and operating lease by lessee [line items]
Minimum lease payments payable under non-cancellable operating lease	£ 723	£ 1,143

Related party transactions (Det

Related party transactions (Details) - Oxford University Innovation Limited - GBP (£)	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018
Disclosure of transactions between related parties [line items]
Fees paid to related party	£ 0	£ 24,000
Amounts payable to related party	£ 0	£ 12,000

Business combinations - Narrati

Business combinations - Narrative (Details) - GBP (£) £ in Thousands	Jan. 31, 2019	Jan. 31, 2018		Dec. 23, 2017
Disclosure of transactions recognised separately from acquisition of assets and assumption of liabilities in business combination [line items]
Goodwill	£ 1,814	£ 2,478	[1]
Discuva Limited
Disclosure of transactions recognised separately from acquisition of assets and assumption of liabilities in business combination [line items]
Percentage of voting equity interests acquired				100.00%
Contingent liabilities recognised as of acquisition date	£ 1,658	£ 1,500
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Business combinations - Schedul

Business combinations - Schedule of Assets Acquired and Liabilities Assumed (Details) - GBP (£) £ in Thousands	Jan. 31, 2019	Jan. 31, 2018
Recognized amounts of identifiable assets acquired and liabilities assumed
Goodwill	£ 1,814	£ 2,478	[1]
Discuva Limited
Recognized amounts of identifiable assets acquired and liabilities assumed
Assumed contingent liabilities	£ (1,658)	£ (1,500)
[1]	See Note 3 - ‘Changes to accounting policies - Adoption of IFRS 15 Revenue from contracts with customers.’

Uncategorized Items - smmt-2019

Label	Element	Value
IFRS 15 [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption1	smmt_CumulativeEffectofNewAccountingPrincipleinPeriodofAdoption1	£ (13,059,000)
Accumulated other comprehensive income [member] | IFRS 15 [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption1	smmt_CumulativeEffectofNewAccountingPrincipleinPeriodofAdoption1	£ (13,059,000)