Xenon Pharmaceuticals (XENE) 10-Q 6 Nov 18 2018 Q3 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Nov. 02, 2018
Document And Entity Information [Abstract]
Entity Registrant Name	Xenon Pharmaceuticals Inc.
Document Type	10-Q
Trading Symbol	XENE
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Entity Central Index Key	1,582,313
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Entity Common Stock, Shares Outstanding		25,240,348

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 87,962	$ 20,486
Marketable securities	39,166	23,181
Accounts receivable	180	438
Prepaid expenses and other current assets	2,185	716
Total current assets	129,493	44,821
Prepaid expenses, long term		230
Property, plant and equipment, net	962	1,070
Total assets	130,455	46,121
Current liabilities:
Accounts payable and accrued expenses (note 7)	4,413	3,383
Loan payable, current portion (note 8)		700
Total current liabilities	4,413	4,083
Loan payable, long-term (note 8)	14,886	6,104
Total liabilities	19,299	10,187
Shareholders’ equity:
Preferred shares, without par value; unlimited shares authorized; issued and outstanding: 1,568,000 (December 31, 2017 - nil) (note 9b)	11,932
Common shares, without par value; unlimited shares authorized; issued and outstanding: 25,187,441 (December 31, 2017 - 17,998,420) (note 9)	261,655	173,841
Additional paid-in capital	37,886	36,471
Accumulated deficit	(199,327)	(173,388)
Accumulated other comprehensive loss	(990)	(990)
Shareholders' equity	111,156	35,934
Total liabilities and shareholders’ equity	130,455	46,121
Commitments and contingencies (note 10)

Consolidated Balance Sheets (_2

Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Preferred shares, without par value
Preferred shares, shares authorized	Unlimited	Unlimited
Preferred shares, issued	1,568,000	0
Preferred shares, outstanding	1,568,000	0
Common shares, without par value
Common shares, shares authorized	Unlimited	Unlimited
Common shares, Issued	25,187,441	17,998,420
Common shares, Outstanding	25,187,441	17,998,420

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenue:
Collaboration revenue		$ 264		$ 295
Type of Revenue [Extensible List]	us-gaap:LicenseAndServiceMember	us-gaap:LicenseAndServiceMember	us-gaap:LicenseAndServiceMember	us-gaap:LicenseAndServiceMember
Operating expenses:
Research and development	$ 6,240	$ 7,164	$ 17,228	$ 19,176
General and administrative	1,938	1,744	6,354	5,643
Buy-out of future milestones and royalties (note 10c)	6,000		6,000
Total operating expenses	14,178	8,908	29,582	24,819
Loss from operations	(14,178)	(8,644)	(29,582)	(24,524)
Other income (expense):
Interest income	325	124	558	382
Interest expense	(678)		(1,037)
Foreign exchange gain (loss)	148	778	(276)	1,503
Gain on termination of collaboration agreement (note 9c)			4,398
Net loss and comprehensive loss	(14,383)	(7,742)	(25,939)	(22,639)
Net loss attributable to preferred shareholders	(1,621)		(2,506)
Net loss attributable to common shareholders	$ (12,762)	$ (7,742)	$ (23,433)	$ (22,639)
Net loss per common share (note 5):
Basic	$ (0.63)	$ (0.43)	$ (1.34)	$ (1.26)
Diluted	$ (0.63)	$ (0.43)	$ (1.34)	$ (1.27)
Weighted-average common shares outstanding (note 5):
Basic	20,306,298	17,998,420	17,472,403	17,980,608
Diluted	20,306,298	18,009,979	17,472,403	18,000,066

Consolidated Statement of Share

Consolidated Statement of Shareholders' Equity (Unaudited) - USD ($) $ in Thousands		Total	Convertible Preferred Shares [Member]	Common Shares [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss [Member]	[1]
Balance at Dec. 31, 2016		$ 63,901		$ 173,246	$ 34,326	$ (142,681)	$ (990)
Balance (in Shares) at Dec. 31, 2016				17,930,590
Net loss		(30,704)				(30,704)
Stock-based compensation expense		2,460			2,460
Issued pursuant to exercise of stock options		177		$ 595	(415)	(3)
Issued pursuant to exercise of stock options (in Shares)				67,830
Issuance of warrants		100			100
Balance at Dec. 31, 2017		35,934		$ 173,841	36,471	(173,388)	(990)
Balance (in Shares) at Dec. 31, 2017				17,998,420
Net loss		(25,939)				(25,939)
Issuance of common shares,net of issuance costs (note 9a)		102,842		$ 102,842
Issuance of common shares, net of issuance costs (note 9a) (in shares)				9,540,000
Issued (cancelled) pursuant to exchange agreement (note 9b)			$ 21,825	$ (21,825)
Issued (cancelled) pursuant to exchange agreement (note 9b) (in Shares)			2,868,000	(2,868,000)
Conversion of preferred shares to common shares (note 9b)			$ (9,893)	$ 9,893
Conversion of preferred shares to common shares (note 9b) (in shares)			(1,300,000)	1,300,000
Cancelled pursuant to termination of collaboration agreement (note 9c)		(4,470)		$ (4,470)
Cancelled pursuant to termination of collaboration agreement (note 9c) (in Shares)				(1,000,000)
Stock-based compensation expense		$ 1,989			1,989
Issued pursuant to exercise of stock options (in Shares)	[2]	237,848
Issued pursuant to exercise of stock options and warrants		$ 262		$ 1,374	(1,112)
Issued pursuant to exercise of stock options and warrants (in shares)				217,021
Issuance of warrants		538			538
Balance at Sep. 30, 2018		$ 111,156	$ 11,932	$ 261,655	$ 37,886	$ (199,327)	$ (990)
Balance (in Shares) at Sep. 30, 2018			1,568,000	25,187,441
[1]	Our accumulated other comprehensive loss is entirely related to historical cumulative translation adjustments from the application of U.S. dollar reporting when the functional currency of the Company was the Canadian dollar.
[2]	During the nine months ended September 30, 2018, 41,507 stock options were exercised for the same number of common shares for cash (nine months ended September 30, 2017 – 63,425). In the same period, the Company issued 103,189 common shares (nine months ended September 30, 2017 – 4,405) for the cashless exercise of 196,341 stock options (nine months ended September 30, 2017 – 7,581).

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Operating activities:
Net loss	$ (25,939)	$ (22,639)
Items not involving cash:
Depreciation	445	502
Amortization of discount on term loan	156
Stock-based compensation	2,050	1,643
Unrealized foreign exchange (gain) loss	269	(1,585)
Gain on termination of collaboration agreement (note 9c)	(4,398)
Changes in operating assets and liabilities:
Accounts receivable	255	77
Prepaid expenses, and other current assets	(1,469)	243
Prepaid expenses, long term	230	190
Accounts payable and accrued expenses	919	(319)
Net cash used in operating activities	(27,482)	(21,888)
Investing activities:
Purchases of property, plant and equipment	(337)	(252)
Purchase of marketable securities	(50,130)	(22,281)
Proceeds from marketable securities	34,036	41,024
Net cash provided by (used in) investing activities	(16,431)	18,491
Financing activities:
Proceeds from issuance of refinanced term loan, net of issuance costs (note 8)	8,453
Issuance of common shares, net of issuance costs (note 9a)	102,842
Issuance of common shares pursuant to exercise of stock options	262	177
Net cash provided by financing activities	111,557	177
Effect of exchange rate changes on cash and cash equivalents	(168)	813
Increase (decrease) in cash and cash equivalents	67,476	(2,407)
Cash and cash equivalents, beginning of period	20,486	17,095
Cash and cash equivalents, end of period	87,962	14,688
Supplemental disclosures:
Interest paid	338
Interest received	518	544
Supplemental disclosures of non-cash transactions:
Fair value of stock options and warrants exercised on a cashless basis	1,112	$ 25
Issuance of preferred shares in exchange for common shares (note 9b)	21,825
Conversion of preferred shares to common shares (note 9b)	9,893
Teva Pharmaceuticals International GmbH and Teva Canada Limited [Member]
Supplemental disclosures of non-cash transactions:
Termination of Teva agreement through cancellation of common shares (note 9c)	$ 4,470

Nature of the Business

Nature of the Business	9 Months Ended
	Sep. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature of the business	1. Nature of the business: Xenon Pharmaceuticals Inc. (the “Company”), incorporated in 1996 under the British Columbia Business Corporations Act and continued federally in 2000 under the Canada Business Corporation Act, is a clinical stage biopharmaceutical company focused on developing innovative therapeutics to improve the lives of patients with neurological disorders. Building upon its extensive knowledge of human genetics and diseases caused by mutations in ion channels, known as channelopathies, the Company is advancing a novel product pipeline of neurology therapies to address areas of high unmet medical need, such as epilepsy, migraine and pain. The Company has incurred significant operating losses since inception. As of September 30, 2018, the Company had an accumulated deficit of $199,327 and a $25,939 net loss for the nine months ended September 30, 2018. Management expects to continue to incur significant expenses in excess of revenue and to incur operating losses for the foreseeable future. To date, the Company has financed its operations primarily through funding received from collaboration and license agreements, private placements of common and preferred shares, public offerings of common shares, debt financing, and government funding. Until such time as the Company can generate substantial product revenue, if ever, management expects to finance the Company’s cash needs through a combination of collaboration agreements and equity or debt financings. The continuation of the research and development activities and the future commercialization of its products are dependent on the Company’s ability to successfully raise additional funds when needed. It is not possible to predict either the outcome of future research and development programs or the Company’s ability to continue to fund these programs in the future.

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Basis of presentation	2. Basis of presentation: These consolidated financial statements are presented in U.S. dollars. The Company has one wholly-owned subsidiary as of September 30, 2018, Xenon Pharmaceuticals USA Inc., which was incorporated in Delaware on December 2, 2016. These unaudited interim consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary. All intercompany transactions and balances have been eliminated on consolidation. The accompanying unaudited interim consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles (“U.S. GAAP”) and pursuant to the rules and regulations of the United States Securities and Exchange Commission (“SEC”) for interim financial information. Accordingly, these consolidated financial statements do not include all of the information and footnotes required for complete consolidated financial statements and should be read in conjunction with the audited consolidated financial statements and notes for the year ended December 31, 2017 and included in the Company’s 2017 Annual Report on Form 10-K filed with the SEC and with the securities commissions in British Columbia, Alberta and Ontario on March 7, 2018. These unaudited interim consolidated financial statements reflect all adjustments, consisting of normal recurring adjustments, which, in the opinion of management, are necessary for a fair presentation of results for the interim periods presented. The results of operations for the three and nine month periods ended September 30, 2018 and 2017 are not necessarily indicative of results that can be expected for a full year. These unaudited interim consolidated financial statements follow the same significant accounting policies as those described in the notes to the audited consolidated financial statements of the Company included in the Company’s 2017 Annual Report on Form 10-K for the year ended December 31, 2017, with the exception of the policy described in note 3 below.

Changes in Significant Accounti

Changes in Significant Accounting Policies	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Changes in significant accounting policies	3. Changes in significant accounting policies: The new revenue standard (Accounting Standards Codification “ASC” 606) became effective for the Company on January 1, 2018, and was adopted using the modified retrospective method under which previously presented financial statements are not restated and the cumulative effect of adopting the new revenue standard on contracts in process is recognized by an adjustment to retained earnings at the effective date. The adoption of the new revenue standard did not change the Company’s recognized revenue under its one ongoing significant collaborative research and license agreement with Genentech, a member of the Roche Group, described in note 11b to the audited consolidated financial statements of the Company included in the Company’s 2017 Annual Report on Form 10-K for the year ended December 31, 2017 and no cumulative effect adjustment was required. The new guidance in ASC 606 requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers under a five-step model: (i) identify 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 a performance obligation is satisfied. The Company generates revenue primarily through collaboration agreements. Such agreements may require the Company to deliver various rights and/or services, including intellectual property rights or licenses and research and development services. Under such collaboration agreements, the Company is generally eligible to receive non-refundable upfront payments, funding for research and development services, milestone payments, and royalties. In contracts where the Company has more than one performance obligation to provide its customer with goods or services, each performance obligation is evaluated to determine whether it is distinct based on whether (i) the customer can benefit from the good or service either on its own or together with other resources that are readily available and (ii) the good or service is separately identifiable from other promises in the contract. The consideration under the contract is then allocated between the distinct performance obligations based on their respective relative stand-alone selling prices. The estimated stand-alone selling price of each deliverable reflects the Company’s best estimate of what the selling price would be if the deliverable was regularly sold on a stand-alone basis and is determined by reference to market rates for the good or service when sold to others or by using an adjusted market assessment approach if selling price on a stand-alone basis is not available. The consideration allocated to each distinct performance obligation is recognized as revenue when control is transferred to the customer for the related goods or services. Consideration associated with at-risk substantive performance milestones, including sales-based milestones, is recognized as revenue when it is probable that a significant reversal of the cumulative revenue recognized will not occur. Sales-based royalties received in connection with licenses of intellectual property are subject to a specific exception in the revenue standards, whereby the consideration is not included in the transaction price and recognized in revenue until the customer’s subsequent sales or usages occur.

Future Changes in Accounting Po

Future Changes in Accounting Policies	9 Months Ended
	Sep. 30, 2018
Accounting Changes And Error Corrections [Abstract]
Future changes in accounting policies	4. Future changes in accounting policies: In February 2016, the FASB issued Accounting Standards Update (“ASU”) 2016-02, Leases (Topic 842): Recognition and Measurement of Financial Assets and Financial Liabilities. The update requires the recognition of lease assets and lease liabilities by lessees for those leases classified as operating leases under previous U.S. GAAP. The new guidance retains a distinction between finance leases and operating leases, with cash payments from operating leases classified within operating activities in the statement of cash flows. These amendments will be effective for public entities for fiscal years and interim periods within those years, beginning after December 15, 2018. The Company plans to adopt the standard on January 1, 2019 and can elect to record a cumulative-effect adjustment as of the beginning of the year of adoption or apply a modified retrospective transition approach. The Company has identified one operating lease for its premises which will be subject to the new guidance and will be recognized as an operating lease liability and right-of-use asset upon adoption.

Net Income (Loss) Per Common an

Net Income (Loss) Per Common and Preferred Share	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Net income (loss) per common and preferred share	5. Net income (loss) per common and preferred share: Basic net income (loss) per common share is calculated using the two-class method required for participating securities which includes the convertible preferred shares as a separate class. The preferred shares entitle the holders to participate in dividends and in earnings and losses of the Company on an equivalent basis as common shares. Accordingly, undistributed earnings (losses) are allocated to common shares and participating preferred shares based on the weighted-average shares of each class outstanding during the period. The treasury stock method is used to compute the dilutive effect of the Company’s stock options and warrants. Under this method, the incremental number of common shares used in computing diluted net income (loss) per common share is the difference between the number of common shares assumed issued and purchased using assumed proceeds. The if-converted method is used to compute the dilutive effect of the Company’s convertible preferred shares. Under the if-converted method, dividends on the preferred shares, if applicable, are added back to earnings attributable to common shareholders, and the preferred shares and paid-in kind dividends are assumed to have been converted at the share price applicable at the end of the period. The if-converted method is applied only if the effect is dilutive. For the three and nine month periods ended September 30, 2018, all stock options, warrants and convertible preferred shares were anti-dilutive and were excluded from the diluted weighted average common shares outstanding for the period. For the three and nine months ended September 30, 2017, 2,214,110 and 2,128,751 stock options, respectively, were excluded from the calculation of diluted net loss per common share as their inclusion would be anti-dilutive. No warrants or convertible preferred shares were outstanding during the three and nine months ended September 30, 2017. The following table sets out the computation of basic and diluted net loss per common and preferred share: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Numerator: Common Shares Preferred Shares Common Shares Preferred Shares Common Shares Preferred Shares Common Shares Preferred Shares Allocation of loss attributed to shareholders Basic $ (12,762 ) $ (1,621 ) $ (7,742 ) $ — $ (23,433 ) $ (2,506 ) $ (22,639 ) $ — Adjustment for change in fair value of liability classified stock options — — (20 ) — — — (182 ) — Diluted $ (12,762 ) $ (1,621 ) $ (7,762 ) $ — $ (23,433 ) $ (2,506 ) $ (22,821 ) $ — Denominator: Weighted average number of shares: Basic 20,306,298 2,579,111 17,998,420 — 17,472,403 1,868,815 17,980,608 — Adjustment for dilutive effect of stock options — — 11,559 — — — 19,458 — Diluted 20,306,298 2,579,111 18,009,979 — 17,472,403 1,868,815 18,000,066 — Net loss attributable to shareholders per share - basic $ (0.63 ) $ (0.63 ) $ (0.43 ) $ — $ (1.34 ) $ (1.34 ) $ (1.26 ) $ — Net loss attributable to shareholders per share - diluted $ (0.63 ) $ (0.63 ) $ (0.43 ) $ — $ (1.34 ) $ (1.34 ) $ (1.27 ) $ —

Fair Value of Financial Instrum

Fair Value of Financial Instruments	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair value of financial instruments	6. Fair value of financial instruments: Certain financial instruments and other items are measured at fair value. To determine the fair value, the Company uses the fair value hierarchy for inputs used to measure fair value of financial assets and liabilities. This hierarchy prioritizes the inputs to valuation techniques used to measure fair value into three levels: Level 1 (highest priority), Level 2, and Level 3 (lowest priority). • Level 1 - Unadjusted quoted prices in active markets for identical instruments. • Level 2 - Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly. Level 2 inputs include quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (i.e., interest rates, yield curves, etc.), and inputs that are derived principally from or corroborated by observable market data by correlation or other means (market corroborated inputs). • Level 3 - Inputs are unobservable and reflect the Company’s assumptions as to what market participants would use in pricing the asset or liability. The Company develops these inputs based on the best information available. Assets and liabilities are classified based on the lowest level of input that is significant to the fair value measurements. Changes in the observability of valuation inputs may result in a reclassification of levels for certain securities within the fair value hierarchy. The Company’s Level 1 assets include cash and cash equivalents and marketable securities with quoted prices in active markets. The carrying amount of accounts receivables, accounts payable and accrued expenses approximates fair value due to the nature and short-term of those instruments. The Company’s term loan bears interest at a rate that approximates prevailing market rates for instruments with similar characteristics and, accordingly, the carrying value of the loan approximates fair value.

Accounts Payable and Accrued Ex

Accounts Payable and Accrued Expenses	9 Months Ended
	Sep. 30, 2018
Payables And Accruals [Abstract]
Accounts Payable and Accrued Expenses	7. Accounts payable and accrued expenses: Accounts payable and accrued expenses consisted of the following: September 30, December 31, 2018 2017 Trade payables $ 959 $ 1,253 Employee compensation, benefits, and related accruals 1,180 1,017 Consulting and contracted research 1,797 817 Professional fees 415 252 Other 62 44 Total $ 4,413 $ 3,383

Term Loan

Term Loan	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Term Loan	8. Term loan: In December 2017, the Company entered into a Loan and Security Agreement (the “Loan Agreement”) with Silicon Valley Bank (the “Bank”) under which the Company was funded an initial tranche of $7,000. In June 2018, the Company entered into a First Loan Modification Amendment (the “Modification”) to the Loan Agreement (together, the “Modified Loan Agreement”), p ursuant to which the Bank accelerated the availability of a second tranche of $5,000 which was funded on the date of the Modification. In August 2018, the Company entered into an Amended and Restated Loan and Security Agreement (the “Amended and Restated Loan Agreement”) with the Bank, pursuant to which the Bank agreed to extend a term loan to the Company with a principal amount of $15,500 (the “Term Loan”). The Term Loan was used to repay in full outstanding borrowings of $12,000 under the Modified Loan Agreement and a payment of $485, which represented the current portion of the final payment fee due under the Modified Loan Agreement, as well as for working capital and other general corporate purposes, including the advancement of the Company’s clinical development programs. The Term Loan accrues interest at a floating per annum rate of 0.5% above the prime rate, which is payable monthly commencing in September 2018. The Term Loan is interest-only until March 31, 2020, followed by 30 equal monthly installments of principal plus interest, maturing on September 1, 2022. In addition, the Company is required to pay a final payment fee of 6.5% of the Term Loan on the date on which the term loan is prepaid, paid or becomes due and payable in full. The Company may prepay all, but not less than all, of the Term Loan subject to a prepayment fee of $295, which represents the deferred portion of the final payment fee due under the Modified Loan Agreement, plus 3.0% if prepaid prior to the first anniversary of the effective date of the Amended and Restated Loan Agreement, 2.0% if prepaid on or after the first anniversary, but prior to the second anniversary, or 1.0%, if prepaid on or after the second anniversary but prior to the maturity date. As security for its obligations under the Amended and Restated Loan Agreement, the Company granted the Bank a first priority security interest on substantially all of the Company’s assets except its intellectual property and subject to certain other exceptions. At September 30, 2018, the Company determined the effective interest rate on the Amended and Restated Loan Agreement with the Bank Interest expense was $678 and $1,037 for the three and nine months ended September 30, 2018, respectively. The outstanding loan and unamortized debt discount balances as of September 30, 2018 in accordance with the repayment terms under Amended and Restated Loan Agreement are as follows: September 30, 2018 Term loan $ 15,500 Less: unamortized discount on loan (657 ) Less: current portion — Accrued portion of final payment fee 43 Loan payable, long-term $ 14,886 Scheduled principal payments on outstanding debt, excluding the final payment fee of $1,008, as of September 30, 2018 in accordance with the repayment terms under Amended and Restated Loan Agreement, are as follows: 2018 $ — 2019 — 2020 5,167 2021 6,200 2022 4,133 Total $ 15,500 The Amended and Restated Loan Agreement contains customary representations and warranties, events of default (including an event of default upon the occurrence of a material impairment on the Bank’s security interest over the collateral, and a material adverse change of the Company) and affirmative and negative covenants, including, among others, covenants that limit or restrict the Company’s ability to incur indebtedness, grant liens, merge or consolidate, dispose of assets, make investments, make acquisitions, enter into certain transactions with affiliates, engage in any new line of business, pay dividends or make distributions, or repurchase stock, in each case subject to certain exceptions. Upon the occurrence and during the continuance of an event of default, a default interest rate will apply that is 5.0% above the otherwise applicable interest rate. The Company is in compliance with these covenants at September 30, 2018. In connection with the Modification, the number of common shares exercisable pursuant to the warrant issued to the Bank in December 2017 under the Loan Agreement (the “December 2017 Warrant”) December 2017 Warrant December 2017 Warrant allowed December 2017 Warrant December 2017 Warrant In connection with the Amended and Restated Loan Agreement, the Company issued a new warrant to the Bank to purchase 40,000 of the Company’s common shares at a price per common share of $9.79. The warrant is immediately exercisable, has a 10-year term and contains a cashless exercise provision.

Share Capital

Share Capital	9 Months Ended
	Sep. 30, 2018
Stockholders Equity Note [Abstract]
Share Capital	9. Share capital: (a) Financing: In May 2018, the Company entered into an at-the-market equity offering sales agreement with Stifel Nicolaus & Company, Incorporated (“Stifel”) to sell common shares of the Company having aggregate gross proceeds of up to $30,000, from time to time, through an “at-the-market” equity offering program under which Stifel would act as sales agent. As of September 30, 2018, the Company had sold 3,440,000 common shares under the sales agreement for proceeds of approximately $29,200, net of commissions paid, but excluding estimated transaction expenses. In July 2018, the Company entered into an at-the-market equity offering sales agreement with Jefferies LLC (“Jefferies”) and Stifel, to sell common shares of the Company having aggregate gross proceeds of up to $50,000, from time to time, through an “at-the-market” equity offering program under which Jefferies and Stifel would act as sales agent. As of September 30, 2018, the Company had sold 1,600,000 common shares under the sales agreement for proceeds of approximately $14,820, net of commissions paid, but excluding estimated transaction expenses. In connection with the Company’s entry into the July 2018 sales agreement with Jefferies and Stifel, the May 2018 sales agreement was mutually terminated by the Company and Stifel. In September 2018, the Company entered into an underwriting agreement with Jefferies and Stifel, relating to an underwritten public offering of 4,500,000 common shares sold by the Company at a public offering price of $14.00 per common share. The Company received net proceeds of $59,220, net of underwriting discounts and commissions, but before offering expenses. In connection with the Company’s entry into the September 2018 underwriting agreement with Jefferies and Stifel, the July 2018 sales agreement was mutually terminated by the Company, Jefferies and Stifel. (b) Exchange agreement with certain funds affiliated with BVF Partners L.P. (collectively, “BVF”): In March 2018, the Company and BVF entered into an exchange agreement pursuant to which the Company issued to BVF 2,868,000 Series 1 Preferred Shares in exchange for 2,868,000 common shares which were subsequently cancelled by the Company. The Company filed articles of amendment creating an unlimited number of Series 1 Preferred Shares. The Series 1 Preferred Shares are convertible into common shares on a one-for-one basis subject to the holder, together with its affiliates, beneficially owning no more than 9.99% of the total number of common shares issued and outstanding immediately after giving effect to such conversion (the “Beneficial Ownership Limitation”). The holder may reset the Beneficial Ownership Limitation to a higher or lower number, not to exceed 19.99% of the total number of common shares issued and outstanding immediately after giving effect to such conversion, upon providing written notice to the Company which will be effective 61 days after delivery of such notice. Each Series 1 Preferred Share is also convertible into one common share at any time at the Company’s option without payment of additional consideration, provided that prior to any such conversion, the holder, together with its affiliates, beneficially owns less than 5.00% of the total number of common shares issued and outstanding and such conversion will not result in the holder, together with its affiliates, beneficially holding more than 5.00% of the total number of common shares issued and outstanding immediately after giving effect to such conversion. In the event of a change of control, holders of Series 1 Preferred Shares shall be issued one common share for each outstanding Series 1 Preferred Share held immediately prior to the change of control (without regard to the Beneficial Ownership Limitation), and following such conversion, will be entitled to receive the same kind and amount of securities, cash or property that a holder of common shares is entitled to receive in connection with such change of control. The Series 1 Preferred Shares rank equally to the common shares in the event of liquidation, dissolution or winding up or other distribution of the assets of the Company among its shareholders and the holders of the Series 1 Preferred Shares are entitled to vote together with the common shares on an as-converted basis and as a single class, subject in the case of each holder of the Series 1 Preferred Shares to the Beneficial Ownership Limitation. Any Series 1 Preferred Shares that are ineligible to be converted into common shares due to the Beneficial Ownership Limitation, measured as of a given record date that applies for a shareholder meeting or ability to act by written consent, shall be deemed to be non-voting securities of the Company. Holders of Series 1 Preferred Shares are entitled to receive dividends (without regard to the Beneficial Ownership Limitation) on the same basis as the holders of common shares. The Company may not redeem the Series 1 Preferred Shares. The Company recorded the issuance of Series 1 Preferred Shares and corresponding cancellation of common shares at $7.61 per share, the estimated weighted average cost at which BVF acquired the common shares. The Series 1 Preferred Shares are recorded wholly as equity under ASC 480, with no bifurcation of conversion feature from the host contract, given that the Series 1 Preferred Shares cannot be cash settled and have no redemption features. In September 2018, BVF converted 1,300,000 Series 1 Preferred Shares in exchange for an equal number of common shares of the Company. (c) Termination of collaboration agreement with Teva Pharmaceuticals International GmbH and Teva Canada Limited (together, “Teva”): In March 2018, the Company and Teva, entered into a termination agreement terminating by mutual agreement the collaborative development and license agreement dated December 7, 2012, as amended. In connection with the termination, Teva returned and the Company cancelled 1,000,000 common shares that were owned by Teva. Pursuant to the terms of the termination agreement, Teva also agreed to return, license or assign to the Company certain intellectual property, including certain patent rights and will transfer regulatory filings related to TV-45070 to the Company. The termination agreement requires the Company to pay a low single-digit percentage royalty to Teva based on net sales of approved products, if any, resulting from any continued development and commercialization of TV-45070 by the Company during the period that assigned or licensed patents cover such products. To date, no such sales have occurred. The Company recorded a gain on the termination of the collaboration agreement of $4,398, net of direct costs incurred in connection with the termination and cancellation of 1,000,000 common shares, based on the estimated fair value represented by the market price of the common shares prior to the closing of the transaction. (d) Stock-based compensation: The following table presents stock option activity for the period: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Outstanding, beginning of period 2,831,985 2,276,897 2,339,905 1,910,823 Granted 12,000 1,050 698,450 447,550 Exercised (1) (119,129 ) — (237,848 ) (71,006 ) Forfeited, cancelled or expired (42,593 ) (70,567 ) (118,244 ) (79,987 ) Outstanding, end of period 2,682,263 2,207,380 2,682,263 2,207,380 Exercisable, end of period 1,471,329 1,417,660 1,471,329 1,417,660 (1) The fair value of each stock option granted is estimated using the Black-Scholes option-pricing model with the following weighted-average assumptions: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Average risk-free interest rate 2.81 % 1.99 % 2.79 % 2.41 % Expected volatility 76 % 81 % 75 % 81 % Average expected term (in years) 6.27 6.50 7.39 7.48 Expected dividend yield 0 % 0 % 0 % 0 % Weighted average fair value of stock options $ 8.75 $ 2.01 $ 3.70 $ 6.10

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	10. Co m (a) Priority access agreement with Medpace Inc. (“Medpace”): In August 2015, the Company entered into a priority access agreement with Medpace for the provision of certain clinical development services. Under the terms of the agreement, the Company has committed to using Medpace non-exclusively for clinical development services over the five year term of the agreement. In consideration for priority access to Medpace resources and preferred service rates, the Company has committed to $7,000 of services over the term of the agreement, $3,000 of which was paid in the year ended December 31, 2015. (b) License, manufacture and supply agreement: In March 2017, the Company entered into a license, manufacture and supply agreement with a pharmaceutical contract manufacturing organization for the access and use of certain regulatory documents as well as for the manufacture and supply of clinical and commercial drug product to support the development of XEN007. Under the terms of the agreement, the Company paid an upfront fee of $500 CAD and will be required to pay a low single-digit percentage royalty on net sales of any products developed and commercialized under the agreement. (c) Asset purchase agreement with 1st Order Pharmaceuticals, Inc. (“1st Order”): In April 2017, the Company acquired XEN1101 (previously known as 1OP2198) from 1st Order pursuant to an asset purchase agreement. 1st Order previously acquired 1OP2198 from Valeant Pharmaceuticals Luxembourg S.a.r.l., an indirect subsidiary of Bausch Health Companies Inc. (together with Valeant Pharmaceuticals Ireland Limited, “Bausch Health”) and the Company has assumed certain financial responsibilities under that agreement. Under the terms of the agreement, the Company paid an upfront fee of $350 and milestone payments in 2017 totaling $700, which were expensed as research and development. In September 2018, the Company entered into a milestone and royalty buy-out agreement with Bausch Health under which all potential clinical development, regulatory and sales-based milestones and royalties on commercial sales with respect to XEN1101 that may become owed to Bausch Health under the asset purchase agreement were terminated in exchange for a one-time payment of $6,000 which was expensed in the period. Future potential payments to 1st Order include $500 in clinical development milestones, up to $6,000 in regulatory milestones, and $1,500 in other milestones, which may be payable pre-commercially. There are no royalty obligations to 1 st Order. (d) License agreement In July 2017, the Company entered into a license agreement with a pharmaceutical company for the access and use of certain regulatory documents to support the development of XEN007. Under the terms of the agreement, the Company paid an upfront fee of $1,000, which was expensed as research and development. Future potential payments include $2,000 in clinical development milestones, up to $7,000 in regulatory milestones, plus a low-to-mid single-digit percentage royalty on net sales of any products developed and commercialized under the agreement. (e) Guarantees and indemnifications: The Company has entered into license and research agreements with third parties that include indemnification provisions that are customary in the industry. These indemnification provisions generally require the Company to compensate the other party for certain damages and costs incurred as a result of third party claims or damages arising from these transactions. The maximum amount of potential future indemnification is unlimited; however, the Company currently holds commercial and product liability insurance. This insurance limits the Company’s exposure and may enable it to recover a portion of any future amounts paid. Historically, the Company has not made any indemnification payments under such agreements and the Company believes that the fair value of these indemnification obligations is minimal. Accordingly, the Company has not recognized any liabilities relating to these obligations for any period presented.

Related Parties

Related Parties	9 Months Ended
	Sep. 30, 2018
Related Party Transactions [Abstract]
Related Parties	11. Related parties: (a) Exchange agreement with BVF: In March 2018, the Company and BVF entered into an exchange agreement pursuant to which the Company issued 2,868,000 Series 1 Preferred Shares in exchange for 2,868,000 common shares which were subsequently cancelled by the Company . Prior to the closing of the transactions contemplated in the exchange agreement, BVF held a number of common shares representing approximately 19.9% of the Company’s then outstanding common shares. For additional information regarding the Series 1 Preferred Shares, refer to note 9b. (b) Termination of collaboration agreement with Teva: In March 2018, the Company and Teva, entered into a termination agreement terminating by mutual agreement the collaborative development and license agreement dated December 7, 2012, as amended. In connection with the termination, the Company cancelled 1,000,000 common shares that were owned by Teva. Prior to the share cancellation, Teva owned more than 5% of the Company’s outstanding common shares. For additional information regarding the termination agreement and the share cancellation, refer to note 9c.

Net Income (Loss) Per Common _2

Net Income (Loss) Per Common and Preferred Share (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Computation of Basic and Diluted Net Loss Per Common and Preferred Share	The following table sets out the computation of basic and diluted net loss per common and preferred share: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Numerator: Common Shares Preferred Shares Common Shares Preferred Shares Common Shares Preferred Shares Common Shares Preferred Shares Allocation of loss attributed to shareholders Basic $ (12,762 ) $ (1,621 ) $ (7,742 ) $ — $ (23,433 ) $ (2,506 ) $ (22,639 ) $ — Adjustment for change in fair value of liability classified stock options — — (20 ) — — — (182 ) — Diluted $ (12,762 ) $ (1,621 ) $ (7,762 ) $ — $ (23,433 ) $ (2,506 ) $ (22,821 ) $ — Denominator: Weighted average number of shares: Basic 20,306,298 2,579,111 17,998,420 — 17,472,403 1,868,815 17,980,608 — Adjustment for dilutive effect of stock options — — 11,559 — — — 19,458 — Diluted 20,306,298 2,579,111 18,009,979 — 17,472,403 1,868,815 18,000,066 — Net loss attributable to shareholders per share - basic $ (0.63 ) $ (0.63 ) $ (0.43 ) $ — $ (1.34 ) $ (1.34 ) $ (1.26 ) $ — Net loss attributable to shareholders per share - diluted $ (0.63 ) $ (0.63 ) $ (0.43 ) $ — $ (1.34 ) $ (1.34 ) $ (1.27 ) $ —

Accounts Payable and Accrued _2

Accounts Payable and Accrued Expenses (Tables)	9 Months Ended
	Sep. 30, 2018
Payables And Accruals [Abstract]
Accounts Payable and Accrued Expenses	Accounts payable and accrued expenses consisted of the following: September 30, December 31, 2018 2017 Trade payables $ 959 $ 1,253 Employee compensation, benefits, and related accruals 1,180 1,017 Consulting and contracted research 1,797 817 Professional fees 415 252 Other 62 44 Total $ 4,413 $ 3,383

Term Loan (Tables)

Term Loan (Tables)	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Schedule of Outstanding Loan and Unamortized Debt Discount Balances	The outstanding loan and unamortized debt discount balances as of September 30, 2018 in accordance with the repayment terms under Amended and Restated Loan Agreement are as follows: September 30, 2018 Term loan $ 15,500 Less: unamortized discount on loan (657 ) Less: current portion — Accrued portion of final payment fee 43 Loan payable, long-term $ 14,886
Schedule of Principal Payments on Outstanding Debt	Scheduled principal payments on outstanding debt, excluding the final payment fee of $1,008, as of September 30, 2018 in accordance with the repayment terms under Amended and Restated Loan Agreement, are as follows: 2018 $ — 2019 — 2020 5,167 2021 6,200 2022 4,133 Total $ 15,500

Share Capital (Tables)

Share Capital (Tables)	9 Months Ended
	Sep. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Option Activity	The following table presents stock option activity for the period: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Outstanding, beginning of period 2,831,985 2,276,897 2,339,905 1,910,823 Granted 12,000 1,050 698,450 447,550 Exercised (1) (119,129 ) — (237,848 ) (71,006 ) Forfeited, cancelled or expired (42,593 ) (70,567 ) (118,244 ) (79,987 ) Outstanding, end of period 2,682,263 2,207,380 2,682,263 2,207,380 Exercisable, end of period 1,471,329 1,417,660 1,471,329 1,417,660 During the nine months ended September 30, 2018, 41,507 stock options were exercised for the same number of common shares for cash (nine months ended September 30, 2017 – 63,425). In the same period, the Company issued 103,189 common shares (nine months ended September 30, 2017 – 4,405) for the cashless exercise of 196,341 stock options (nine months ended September 30, 2017 – 7,581).
Fair Value Assumptions for Stock Options	The fair value of each stock option granted is estimated using the Black-Scholes option-pricing model with the following weighted-average assumptions: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Average risk-free interest rate 2.81 % 1.99 % 2.79 % 2.41 % Expected volatility 76 % 81 % 75 % 81 % Average expected term (in years) 6.27 6.50 7.39 7.48 Expected dividend yield 0 % 0 % 0 % 0 % Weighted average fair value of stock options $ 8.75 $ 2.01 $ 3.70 $ 6.10

Nature of the business (Details

Nature of the business (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Accumulated deficit	$ 199,327		$ 199,327		$ 173,388
Net loss	$ 14,383	$ 7,742	$ 25,939	$ 22,639	$ 30,704

Basis of presentation (Details)

Basis of presentation (Details)	9 Months Ended
	Sep. 30, 2018
Xenon Pharmaceuticals USA Inc. [Member]
Basis Of Presentation [Line Items]
Date of incorporation	Dec. 2, 2016

Net Income (Loss) Per Common _3

Net Income (Loss) Per Common and Preferred Share (Details) - shares	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2017
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Warrants outstanding			0
Convertible Preferred Shares [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Shares outstanding			0
Stock Options [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from the calculation of loss per common share	2,214,110	2,128,751

Net Income (Loss) Per Common _4

Net Income (Loss) Per Common and Preferred Share - Computation of Basic and Diluted Net Loss Per Common and Preferred Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Allocation of loss attributed to shareholders
Basic	$ (12,762)	$ (7,742)	$ (23,433)	$ (22,639)
Basic	$ (1,621)		$ (2,506)
Weighted average number of shares:
Basic	20,306,298	17,998,420	17,472,403	17,980,608
Diluted	20,306,298	18,009,979	17,472,403	18,000,066
Net loss attributable to shareholders per share - basic	$ (0.63)	$ (0.43)	$ (1.34)	$ (1.26)
Net loss attributable to shareholders per share - diluted	$ (0.63)	$ (0.43)	$ (1.34)	$ (1.27)
Common Shares [Member]
Allocation of loss attributed to shareholders
Basic	$ (12,762)	$ (7,742)	$ (23,433)	$ (22,639)
Adjustment for change in fair value of liability classified stock options		(20)		(182)
Diluted	$ (12,762)	$ (7,762)	$ (23,433)	$ (22,821)
Weighted average number of shares:
Basic	20,306,298	17,998,420	17,472,403	17,980,608
Adjustment for dilutive effect of stock options		11,559		19,458
Diluted	20,306,298	18,009,979	17,472,403	18,000,066
Net loss attributable to shareholders per share - basic	$ (0.63)	$ (0.43)	$ (1.34)	$ (1.26)
Net loss attributable to shareholders per share - diluted	$ (0.63)	$ (0.43)	$ (1.34)	$ (1.27)
Preferred Shares [Member]
Allocation of loss attributed to shareholders
Basic	$ (1,621)		$ (2,506)
Diluted	$ (1,621)		$ (2,506)
Weighted average number of shares:
Basic	2,579,111		1,868,815
Diluted	2,579,111		1,868,815
Net loss attributable to shareholders per share - basic	$ (0.63)		$ (1.34)
Net loss attributable to shareholders per share - diluted	$ (0.63)		$ (1.34)

Accounts Payable and Accrued _3

Accounts Payable and Accrued Expenses - Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Payables And Accruals [Abstract]
Trade payables	$ 959	$ 1,253
Employee compensation, benefits, and related accruals	1,180	1,017
Consulting and contracted research	1,797	817
Professional fees	415	252
Other	62	44
Total	$ 4,413	$ 3,383

Term Loan (Details)

Term Loan (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended				3 Months Ended	9 Months Ended
	Sep. 30, 2018	Aug. 31, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2017
Debt Instrument [Line Items]
Debt instrument tranche amount funded	$ 15,500				$ 15,500	$ 15,500
Amortization of the debt discount (recovery) expense						156
Interest expense					678	1,037
Increase in warrants issued				36,008
Warrants outstanding to purchase common stock							0
Silicon Valley Bank [Member]
Debt Instrument [Line Items]
Fair value of warrant	$ 247				$ 247	$ 247
Warrants outstanding to purchase common stock	86,419				86,419	86,419
Warrants exercise price per common share	$ 2.43				$ 2.43	$ 2.43
Warrant exercisable term						10 years
Number of shares issued for cashless exercise	72,325
Loan Agreement [Member] | Silicon Valley Bank [Member]
Debt Instrument [Line Items]
Debt instrument, agreement date				2017-12
Loan Agreement [Member] | Silicon Valley Bank [Member] | Modification [Member]
Debt Instrument [Line Items]
Debt instrument, agreement date			2018-06
Loan Agreement [Member] | Silicon Valley Bank [Member] | Initial Tranche [Member]
Debt Instrument [Line Items]
Debt instrument tranche amount funded				$ 7,000
Loan Agreement [Member] | Silicon Valley Bank [Member] | Initial Tranche [Member] | Modification [Member]
Debt Instrument [Line Items]
Debt instrument principal repayment period				30 months
Debt instrument principal repayment period on achievement of certain clinical milestones				24 months
Debt instrument, maturity date				Mar. 31, 2021
Loan Agreement [Member] | Silicon Valley Bank [Member] | Second Tranche [Member] | Modification [Member]
Debt Instrument [Line Items]
Debt instrument tranche amount funded			$ 5,000
Debt instrument, interest only payment end date			Sep. 30, 2018
Debt instrument principal repayment period			24 months
Debt instrument principal repayment period on achievement of certain clinical milestones			18 months
Debt instrument, maturity date			Sep. 30, 2020
Term Loan [Member]
Debt Instrument [Line Items]
Debt instrument tranche amount funded	$ 15,500				$ 15,500	$ 15,500
Aggregate principal amount of debt instrument		$ 15,500
Repayment of outstanding borrowings of loan agreement		12,000
Repayment of final payment fee		$ 485
Interest expense					678	1,037
Final payment fee						1,008
Term Loan [Member] | Silicon Valley Bank [Member]
Debt Instrument [Line Items]
Amortization of the debt discount (recovery) expense					$ (8)	$ 156
Debt instrument, frequency periodic payment, interest						monthly
Term Loan [Member] | Silicon Valley Bank [Member] | Loan Agreement [Member]
Debt Instrument [Line Items]
Debt instrument, interest only payment end date		Mar. 31, 2020
Debt instrument principal repayment period		30 months
Debt instrument, maturity date		Sep. 1, 2022
Debt instrument, payment commencing period		2018-09
Debt instrument, final payment fee percentage		6.50%
Debt instrument prepayment fee		$ 295
Debt instrument default interest payment above normal interest rate		5.00%
Warrants exercise price per common share		$ 9.79
Warrant exercisable term		10 years
Warrants outstanding to purchase common stock		40,000
Term Loan [Member] | Silicon Valley Bank [Member] | Loan Agreement [Member] | Prior to First Anniversary [Member]
Debt Instrument [Line Items]
Debt instrument, prepayment fee payable on outstanding principal, in percentage		3.00%
Term Loan [Member] | Silicon Valley Bank [Member] | Loan Agreement [Member] | After First Anniversary, but Prior to Second Anniversary [Member]
Debt Instrument [Line Items]
Debt instrument, prepayment fee payable on outstanding principal, in percentage		2.00%
Term Loan [Member] | Silicon Valley Bank [Member] | Loan Agreement [Member] | After Second Anniversary [Member]
Debt Instrument [Line Items]
Debt instrument, prepayment fee payable on outstanding principal, in percentage		1.00%
Term Loan [Member] | Silicon Valley Bank [Member] | Loan Agreement [Member] | Prime Rate [Member]
Debt Instrument [Line Items]
Debt instrument, floating interest rate		0.50%
Term Loan [Member] | Silicon Valley Bank [Member] | Initial Tranche [Member]
Debt Instrument [Line Items]
Effective interest rate on initial tranche of debt instrument	9.29%			9.25%	9.29%	9.29%

Term Loan - Schedule of Outstan

Term Loan - Schedule of Outstanding Loan and Unamortized Debt Discount Balances (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Term loan	$ 15,500
Less: current portion		$ (700)
Loan payable, long-term	14,886	$ 6,104
Term Loan [Member]
Debt Instrument [Line Items]
Term loan	15,500
Less: unamortized discount on loan	(657)
Accrued portion of final payment fee	43
Loan payable, long-term	$ 14,886

Term Loan - Schedule of Princip

Term Loan - Schedule of Principal Payments on Outstanding Debt (Details) $ in Thousands	Sep. 30, 2018USD ($)
Debt Disclosure [Abstract]
2,020	$ 5,167
2,021	6,200
2,022	4,133
Total	$ 15,500

Share Capital (Details)

Share Capital (Details) - USD ($) $ / shares in Units, $ in Thousands	Sep. 30, 2018	Sep. 30, 2018	Jul. 31, 2018	May 31, 2018	Mar. 31, 2018	Sep. 30, 2018
Share Capital [Line Items]
Sale proceeds of common shares						$ 102,842
Gain on termination of collaboration agreement					$ 4,398	$ 4,398
Series1 Preferred Shares
Share Capital [Line Items]
Conversion of shares		1,300,000
Common Shares [Member]
Share Capital [Line Items]
Conversion of shares		1,300,000
BVF Partners L.P [Member] | Exchange Agreement [Member]
Share Capital [Line Items]
Estimated weighted average cancellation price per share of common stock					$ 7.61
BVF Partners L.P [Member] | Exchange Agreement [Member] | Series1 Preferred Shares
Share Capital [Line Items]
Shares issued					2,868,000
Preferred shares convertible into common shares					one-for-one
Common shares issued on conversion of preferred stock					1
Maximum beneficial ownership limitation percentage for conversion of common stock issued and outstanding					9.99%
Maximum beneficial ownership limitation upon notice, percentage for conversion of common stock issued and outstanding					19.99%
Maximum beneficial percentage hold for conversion of number Of common stock issued and outstanding					5.00%
Minimum beneficial percentage hold for conversion of number Of common stock issued and outstanding.					5.00%
BVF Partners L.P [Member] | Exchange Agreement [Member] | Common Shares [Member]
Share Capital [Line Items]
Shares issued					2,868,000
Common Shares [Member]
Share Capital [Line Items]
Shares issued						9,540,000
Conversion of shares						1,300,000
Stifel [Member] | At-The-Market Equity Offering [Member]
Share Capital [Line Items]
Sale proceeds of common shares	$ 29,200
Stifel [Member] | At-The-Market Equity Offering [Member] | Maximum [Member]
Share Capital [Line Items]
Sale proceeds of common shares				$ 30,000
Stifel [Member] | At-The-Market Equity Offering [Member] | Common Shares [Member]
Share Capital [Line Items]
Shares issued	3,440,000
Jefferies and Stifel [Member] | At-The-Market Equity Offering Sales Agreement [Member]
Share Capital [Line Items]
Sale proceeds of common shares	$ 14,820
Jefferies and Stifel [Member] | Maximum [Member] | At-The-Market Equity Offering Sales Agreement [Member]
Share Capital [Line Items]
Sale proceeds of common shares			$ 50,000
Jefferies and Stifel [Member] | Common Shares [Member] | At-The-Market Equity Offering Sales Agreement [Member]
Share Capital [Line Items]
Shares issued	1,600,000
Jefferies and Stifel [Member] | Underwritten Public Offering [Member]
Share Capital [Line Items]
Sale proceeds of common shares		$ 59,220
Jefferies and Stifel [Member] | Underwritten Public Offering [Member] | Common Shares [Member]
Share Capital [Line Items]
Shares issued		4,500,000
Shares price	$ 14	$ 14				$ 14
Teva Pharmaceuticals International GmbH and Teva Canada Limited [Member]
Share Capital [Line Items]
Collaborative development and license agreement termination date					Mar. 31, 2018
Teva Canada Limited [Member]
Share Capital [Line Items]
Number of common shares agreed to transfer and assign for cancellation					1,000,000

Share Capital - Stock Option Ac

Share Capital - Stock Option Activity (Details) - shares		3 Months Ended		9 Months Ended		12 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Options Outstanding, Beginning balance		2,831,985	2,276,897	2,339,905	1,910,823	1,910,823
Number of Options, Granted		12,000	1,050	698,450	447,550
Number of Options, Exercised	[1]	(119,129)		(237,848)	(71,006)
Number of Options, Forfeited, cancelled or expired		(42,593)	(70,567)	(118,244)	(79,987)
Number of Options Outstanding, Ending balance		2,682,263	2,207,380	2,682,263	2,207,380	2,339,905
Number of Options Exercisable		1,471,329	1,417,660	1,471,329	1,417,660
[1]	During the nine months ended September 30, 2018, 41,507 stock options were exercised for the same number of common shares for cash (nine months ended September 30, 2017 – 63,425). In the same period, the Company issued 103,189 common shares (nine months ended September 30, 2017 – 4,405) for the cashless exercise of 196,341 stock options (nine months ended September 30, 2017 – 7,581).

Share Capital - Stock Option _2

Share Capital - Stock Option Activity (Parenthetical) (Details) - shares	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Options exercised for Number of Common Shares for cash	41,507	63,425
Common stock issued for cashless exercise	103,189	4,405
Cashless exercise of stock options	196,341	7,581

Share Capital - Fair Value Assu

Share Capital - Fair Value Assumptions for Stock Options (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Fair Value Assumptions For Stock Options [Abstract]
Average risk-free interest rate	2.81%	1.99%	2.79%	2.41%
Expected volatility	76.00%	81.00%	75.00%	81.00%
Average expected term (in years)	6 years 3 months 7 days	6 years 6 months	7 years 4 months 20 days	7 years 5 months 23 days
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Weighted average fair value of stock options granted	$ 8.75	$ 2.01	$ 3.70	$ 6.10

Commitments and Contingencies (

Commitments and Contingencies (Details)	1 Months Ended				9 Months Ended	12 Months Ended
	Sep. 30, 2018USD ($)	Jul. 31, 2017USD ($)	Apr. 30, 2017USD ($)	Mar. 31, 2017CAD ($)	Sep. 30, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2015USD ($)	Aug. 31, 2015USD ($)
Asset Purchase Agreement [Member] | 1st Order Pharmaceuticals, Inc. [Member]
Commitments and Contingencies [Line Items]
Upfront fee paid			$ 350,000
Milestone payments paid						$ 700,000
Royalty obligations	$ 0				$ 0
Asset Purchase Agreement [Member] | 1st Order Pharmaceuticals, Inc. [Member] | Clinical Development Milestones [Member]
Commitments and Contingencies [Line Items]
Future potential payments					500,000
Asset Purchase Agreement [Member] | 1st Order Pharmaceuticals, Inc. [Member] | Regulatory Milestone [Member] | Maximum [Member]
Commitments and Contingencies [Line Items]
Future potential payments					6,000,000
Asset Purchase Agreement [Member] | 1st Order Pharmaceuticals, Inc. [Member] | Other Milestones [Member]
Commitments and Contingencies [Line Items]
Future potential payments					$ 1,500,000
Asset Purchase Agreement [Member] | 1st Order Pharmaceuticals, Inc. and Bausch Health Companies Inc. [Member]
Commitments and Contingencies [Line Items]
Agreement terminated in exchange for a one-time payment	$ 6,000,000
License Agreement [Member]
Commitments and Contingencies [Line Items]
Upfront fee paid		$ 1,000,000
License Agreement [Member] | Clinical Development Milestones [Member]
Commitments and Contingencies [Line Items]
Future potential payments		2,000,000
License Agreement [Member] | Regulatory Milestone [Member] | Maximum [Member]
Commitments and Contingencies [Line Items]
Future potential payments		$ 7,000,000
Medpace Clinical Development Service Agreement [Member]
Commitments and Contingencies [Line Items]
Service agreement, term					5 years
Committed service obligation								$ 7,000,000
Contractual obligation paid							$ 3,000,000
License, Manufacture and Supply Agreement [Member]
Commitments and Contingencies [Line Items]
Upfront fee paid				$ 500

Related Parties (Details)

Related Parties (Details)	1 Months Ended
	Mar. 31, 2018shares
Teva Pharmaceuticals International GmbH and Teva Canada Limited [Member]
Related Party Transaction [Line Items]
Collaborative development and license agreement termination month and year	2018-03
Teva Pharmaceuticals International GmbH and Teva Canada Limited [Member] | Minimum [Member]
Related Party Transaction [Line Items]
Percentage of ownership	5.00%
Teva Canada Limited [Member]
Related Party Transaction [Line Items]
Number of common shares agreed to transfer and assign for cancellation	1,000,000
BVF Partners L.P [Member] | Exchange Agreement [Member]
Related Party Transaction [Line Items]
Percentage of ownership	19.90%
BVF Partners L.P [Member] | Exchange Agreement [Member] | Series1 Preferred Shares
Related Party Transaction [Line Items]
Stock Issued	2,868,000
Common stock received in exchange of preferred shares	2,868,000