Albireo Pharma (ALBO) 10-Q 9 Aug 18 2018 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2018	Aug. 01, 2018
Document And Entity Information [Abstract]
Entity Registrant Name	Albireo Pharma, Inc.
Entity Central Index Key	1,322,505
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Type	10-Q
Document Period End Date	Jun. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
Trading Symbol	ALBO
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		11,969,928

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 183,228	$ 53,231
Prepaid expenses and other assets	610	1,054
Other receivables	2,406	726
Total current assets	186,244	55,011
Property and equipment, net	210	178
Goodwill	17,260	17,260
Other noncurrent assets	422	775
Total assets	204,136	73,224
Current liabilities:
Trade payables	3,020	1,350
Accrued expenses	4,353	6,105
Other liabilities	541	474
Total current liabilities	7,914	7,929
Liability related to sale of future royalties	46,736
Long-term liabilities	39	42
Total liabilities	54,689	7,971
Stockholders' Equity:
Common stock, $0.01 par value per share — 30,000,000 authorized at June 30, 2018 and December 31, 2017; 11,957,491 and 8,902,784 issued and outstanding at June 30, 2018 and December 31, 2017, respectively	120	89
Additional paid in capital	211,140	114,522
Accumulated other comprehensive income	4,768	1,001
Accumulated deficit	(66,581)	(50,359)
Total stockholders’ equity	149,447	65,253
Total liabilities and stockholders’ equity	$ 204,136	$ 73,224

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) (Unaudited) - $ / shares	Jun. 30, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	30,000,000	30,000,000
Common stock, shares issued	11,957,491	8,902,784
Common stock, shares outstanding	11,957,491	8,902,784

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Statement [Abstract]
Revenue	$ 730,000	$ 1,000	$ 11,932,000	$ 2,000
Operating expenses:
Research and development	6,411,000	2,962,000	12,562,000	5,774,000
General and administrative	4,238,000	3,713,000	8,366,000	6,925,000
Other operating (income) expense, net	487,000	(65,000)	1,991,000	9,000
Total operating expenses	11,136,000	6,610,000	22,919,000	12,708,000
Operating loss	(10,406,000)	(6,609,000)	(10,987,000)	(12,706,000)
Interest income (expense), net	(1,666,000)	(152,000)	(2,682,000)	(401,000)
Other income (expense), net	(2,531,000)	585,000	(2,553,000)	260,000
Net loss before income taxes	(14,603,000)	(6,176,000)	(16,222,000)	(12,847,000)
Income tax	0	0	0	0
Net loss	$ (14,603,000)	$ (6,176,000)	$ (16,222,000)	$ (12,847,000)
Net loss per share - basic and diluted	$ (1.22)	$ (0.86)	$ (1.42)	$ (1.91)
Weighted average shares outstanding - basic and diluted	11,938,357	7,171,610	11,417,463	6,734,555

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (14,603)	$ (6,176)	$ (16,222)	$ (12,847)
Other comprehensive loss:
Foreign currency translation adjustment	2,573	389	3,767	(90)
Total other comprehensive income (loss)	2,573	389	3,767	(90)
Total comprehensive loss	$ (12,030)	$ (5,787)	$ (12,455)	$ (12,937)

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities:
Net loss	$ (16,222)	$ (12,847)
Adjustments to reconcile net loss to net cash used in operating activities:
Non cash interest expense on liability related to royalty monetization	2,028
Accretion of debt discount and amortization of issuance costs		301
Depreciation and amortization	22	13
Change in fair value of financial instruments		(251)
Stock-based compensation expense	2,244	2,051
Unrealized foreign exchange (gain) loss	6,718
Changes in operating assets and liabilities:
Trade receivables	(754)	27
Prepaid expenses and other current assets	432	94
Other receivables	(1,055)	(292)
Other non current assets	354	(12)
Trade payables	1,867	280
Accrued expenses	(2,223)	(3,864)
Other liabilities and long-term liabilities	70	29
Other non current liabilities		43
Net cash used in operating activities	(6,519)	(14,428)
Cash flows from investing activities:
Purchase of property, plant and equipment	(61)	(146)
Net cash used in investing activities	(61)	(146)
Cash flows from financing activities:
Proceeds from issuance of common stock, net of issuance costs	94,149	48,508
Proceeds from royalty agreement	44,525
Exercise of options	255	62
Payments of principal on borrowings		(1,648)
Net cash provided by financing activities	138,929	46,922
Effect of exchange rate changes on cash and cash equivalents	(2,352)	319
Net increase in cash and cash equivalents	129,997	32,667
Cash and cash equivalents—beginning of period	53,231	29,931
Cash and cash equivalents—end of period	$ 183,228	62,598
Supplemental disclosures of cash flow information:
Cash paid for interest		136
Kreos
Supplemental disclosures of cash flow information:
Shares issued upon cashless exercise of Kreos warrants		$ 617

Summary of Significant Accounti

Summary of Significant Accounting Policies and Basis of Presentation	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies and Basis of Presentation	1. Summary of significant accounting policies and basis of presentation Organization Albireo Pharma, Inc. (Parent), together with its direct and indirect subsidiaries (the Company), is a clinical-stage biopharmaceutical company focused on the development and commercialization of novel bile acid modulators to treat orphan pediatric liver diseases and other liver and gastrointestinal diseases and disorders. The Company’s clinical pipeline includes a Phase 3 product candidate, a Phase 2 product candidate, and elobixibat, which is approved in Japan for the treatment of chronic constipation. We also anticipate commencing a development program with elobixibat in nonalcoholic steatohepatitis or NASH. A4250, the Company’s Phase 3 lead product candidate, is in development initially for the treatment of patients with progressive familial intrahepatic cholestasis (PFIC), a rare, life-threatening genetic disorder affecting young children. Basis of presentation The accompanying unaudited Condensed Consolidated Financial Statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) for interim financial information, and the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements and should be read in conjunction with the audited consolidated financial statements and accompanying notes included in our Annual Report on Form 10-K for the fiscal year ended December 31, 2017. In the opinion of management, all adjustments (including normal recurring accruals) considered necessary for fair presentation have been included in the Condensed Consolidated Financial Statements. The results of operations for the three and six months ended June 30, 2018 are not necessarily indicative of the results that may be expected for the full fiscal year, any other interim period or any future fiscal year. The condensed consolidated financial statements are prepared on a basis consistent with prior periods except for the adoption of the new revenue recognition standard discussed below. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (ASC) and Accounting Standards Update (ASU) of the Financial Accounting Standards Board (FASB). Principles of consolidation The accompanying Condensed Consolidated Financial Statements include the accounts of Parent and its direct or indirect wholly owned subsidiaries, Albireo Limited, Albireo AB, Elobix AB, Albireo, Inc., Albireo Security Corp. and Biodel UK Limited. All intercompany balances and transactions have been eliminated in consolidation. Foreign currency translation Functional and presentation currency Items included in the financial statements of each entity comprising the Company are measured using the currency of the primary economic environment in which the entity operates (the functional currency). The functional currency for Parent, Albireo, Inc. and Albireo Security Corp. is the U.S. Dollar (USD), the functional currency for Albireo Limited, Elobix AB and Biodel UK Limited is the Euro, and the functional currency for Albireo AB is the Swedish Krona (SEK). The Company consolidates its financial statements in USD. Transactions and balances Foreign currency transactions in each entity comprising the Company are remeasured into the functional currency of the entity using the exchange rates prevailing at the respective transaction dates. Foreign exchange gains and losses resulting from the settlement of such transactions and from the translation at period-end exchange rates of monetary assets and liabilities denominated in foreign currencies are recognized within Other (income) expense, net in the Condensed Consolidated Statements of Operations as part of operating expenses. The results and financial position of the Company that have a functional currency different from the USD are translated into the presentation currency as follows: a. assets and liabilities presented are translated at the closing exchange rate as of June 30, 2018 and December 31, 2017; b. income and expenses for each statement of comprehensive income (loss) are translated at the average exchange rate for the applicable period; c. significant transactions use the closing exchange rate on the date of the transaction; and d. all resulting exchange differences arising from such translations are recognized directly in other comprehensive income (loss) and presented as a separate component of equity. Use of estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts of assets, liabilities, revenues and expenses reported in the financial statements and accompanying notes. Management must apply significant judgment in this process. On an ongoing basis, the Company evaluates its estimates and assumptions, including but not limited to accruals, deferred tax assets and royalty monetization liability estimated at fair value. Actual results could materially differ from these estimates. Fair value of financial instruments When measuring the fair value of financial instruments, the Company evaluates valuation techniques such as the market approach, the income approach and the cost approach. A three-level valuation hierarchy, which prioritizes the inputs to valuation techniques that are used to measure fair value, is based upon whether such inputs are observable or unobservable. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect market assumptions made by the reporting entity. The three-level hierarchy for the inputs to valuation techniques is briefly summarized as follows: Level 1—Observable inputs such as quoted prices (unadjusted) for identical Level 2—Observable inputs such as quoted prices for similar Level 3—Unobservable inputs that reflect the reporting entity’s estimate of assumptions that market participants would use in pricing the asset or liability. Research and development expenses Research and development costs are expensed as incurred and include primarily salaries, benefits and other staff-related costs; clinical trial and related clinical manufacturing costs; contract services and other outside costs. The Company’s nonclinical studies and clinical trials are performed by third-party contract research organizations (CROs). Some of these expenses are billed monthly for services performed, while others are billed based upon milestones achieved. For nonclinical studies, the significant factors used in estimating accruals include the percentage of work completed to date and contract milestones achieved. For clinical trial expenses, the significant factors used in estimating accruals include the number of patients enrolled and percentage of work completed to date or contract milestones achieved. The Company’s estimates are highly dependent upon the timeliness and accuracy of the data provided by the respective CROs regarding the status of the contracted activity, with adjustments made when deemed necessary. Revenue recognition In 2012, the Company entered into a license agreement (the Agreement) with EA Pharma Co., Ltd. (EA Pharma, formerly Ajinomoto Pharmaceuticals Co., Ltd.) to develop a select product candidate (elobixibat) for registration and subsequent commercialization in select markets. In conjunction with the Agreement, the Company granted EA Pharma an exclusive license to its intellectual property for development and commercialization activities in the designated field and territories. The Company is entitled to payments resulting from pharmaceutical ingredient or related procurement services if provided as part of a development plan. Revenue related to these payments is recorded on a net basis; in this instance, the Company acts as an agent, as it does not have discretion to change suppliers and does not perform any part of the services or manufacture of the subject pharmaceutical ingredients. The costs associated with these activities are netted against the related revenue in the condensed consolidated statements of operations. In 2012, EA Pharma made an upfront cash payment to the Company of €10.0 million under the Agreement. The parties amended the agreement in April 2016, pursuant to which EA Pharma made an additional cash payment to the Company of $8.0 million. As of June 30, 2018, the Company is eligible to receive an additional regulatory-based milestone payment under the Agreement of €4.3 million ($5.0 million based on the Euro to USD exchange rate as of June 30, 2018) if a specified regulatory event is achieved for elobixibat The Agreement will continue until the last royalty period for any product in the territory, which is defined as the period when there are no remaining patent rights or regulatory exclusivity in place for any products subject to royalties. EA Pharma may terminate the Agreement at will upon 180 days’ prior written notice to the Company. Either party may terminate the Agreement for the other party’s uncured material breach or insolvency and in certain other circumstances agreed to by the parties. The Company assessed this arrangement in accordance with Accounting Standards Codification (ASC) Topic 606, Revenue from Contracts with Customers Under the Agreement, in order to evaluate the appropriate transaction price, the Company determined that the upfront amount constituted the entirety of the consideration to be included in the transaction price as of the outset of the arrangement, which was allocated to the single performance obligation. At the outset of the arrangement, the transaction price included only the €10.0 million upfront consideration received, and was increased to include the $8.0 million received in conjunction with the 2016 amendment. The potential milestone payments were excluded from the transaction price, as all milestone amounts were fully constrained. In April 2013, December 2015, and October 2016, various development milestone events were achieved, and the Company recognized revenue related to these events; because the Company previously satisfied its performance obligation to deliver the license, the Company recorded these milestone payments as received. The Company will reevaluate the transaction price at the end of each reporting period and as other uncertain events are resolved or other changes in circumstances occur, and, if necessary, adjust its estimate of the transaction price. In January 2018, the Japanese Ministry of Health Labour and Welfare (MHLW) approved a new drug application filed by EA Pharma for elobixibat for the treatment of chronic constipation, for which the Company received a milestone payment of $11.2 million. Based on the regulatory approval, the Company determined that the milestone was no longer at risk of significant reversal. As such, because the single performance obligation had previously been satisfied, the Company recognized this amount in full in the first quarter of 2018 and there was no deferred revenue or contract asset as of June 30, 2018. Monetization of Future Royalties In December 2017, the Company executed the RIAA with HCR pursuant to which it sold to HCR the right to receive all royalties from sales in Japan and sales milestones achieved from any covered territory potentially payable to the Company under the Agreement, up to a specified maximum “cap” amount of $78.8 million, based on the funds the Company received from HCR to date. The Company received $44.5 million from HCR, net of certain transaction expenses, under the RIAA and the Company is eligible to receive an additional $15.0 million under the RIAA if a specified sales milestone is achieved for elobixibat in Japan. If the cap amount is reached, the Company will again become eligible to receive royalties from Japanese sales and sales milestones from covered territories for elobixibat from EA Pharma under the Agreement. The Company is obligated to make royalty interest payments to HCR under the RIAA only to the extent it receives future Japanese royalties, sales milestones or other specified payments from EA Pharma . Although the Company sold its rights to receive royalties from the sales of elobixibat in Japan, as a result of its ongoing involvement in the cash flows related to these royalties, the Company will continue to account for these royalties as revenue. The Company recorded the $44.5 million as a liability related to sale of future royalties (royalty obligation) in the balance sheet at June 30, 2018. The royalty obligation will be amortized using the effective interest rate method, based on the Company's best estimate of the time it will take to reach the capped amount. The following table shows the activity within the liability account during the period from the inception of the royalty transaction in December 2017 to June 30, 2018: June 30, 2018 (in thousands) Liability related to sale of future royalties—beginning balance $ — Proceeds from sale of future royalties, net 44,525 Unrealized foreign currency (gain)/loss on remeasurement of the liability 2,440 Foreign currency translation (gain)/loss (2,418 ) Accretion of interest expense on liability related to royalty monetzation 2,919 Liability related to sale of future royalties—ending balance $ 47,466 Less current portion classified within other current liabilities (730 ) Net ending Liability related to sale of future royalties $ 46,736 The Company records estimated royalties to accrued other until the payment is received from EA Pharma at which time the Company then remits payment to HCR. As royalties are remitted to HCR, the balance of the royalty obligation will be effectively repaid over the life of the RIAA. In order to determine the amortization of the royalty obligation, the Company is required to estimate the total amount of future royalty payments to be received and submitted to HCR, as noted above, based on the Company's best estimate of the time it will take to reach the cap amount. The sum of these amounts less the $44.5 million proceeds the Company received will be recorded as interest expense over the life of the royalty obligation. Since inception, the Company's estimate of its total interest expense resulted in a quarterly effective interest rate of approximately 4.15%. The Company periodically assesses the estimated royalty payments to HCR and to the extent such payments are greater or less than its initial estimates or the timing of such payments is materially different than its original estimates, the Company will prospectively adjust the accretion of interest on the royalty obligation. There are a number of factors that could materially affect the amount and the timing of royalty payments, most of which are not within the Company's control. Such factors include, but are not limited to, the rate of elobixibat prescriptions, the number of doses administered, the introduction of competing products, manufacturing or other delays, patent protection, adverse events that result in governmental health authority imposed restrictions on the use of the drug products, significant changes in foreign exchange rates as the royalties remitted to HCR are in U.S. dollars while sales of elobixibat are in Japanese yen, and sales never achieving forecasted numbers, which would result in reduced royalty payments, reduced non-cash royalty revenues and reduced non-cash interest expense over the life of the royalty obligation. Loss contingencies Loss contingencies are recorded as liabilities when it is probable that a liability has occurred and the amount of loss is reasonably estimable. Disclosure is required when there is a reasonable possibility that an ultimate loss will be material. Contingent liabilities are often resolved over long periods of time. Estimating probable losses requires analysis that often depends on judgments about potential actions by third parties, such as regulators. Recently adopted accounting pronouncements Effective January 1, 2018, the Company adopted ASC Topic 606, Revenue from Contracts with Customers modified retrospective transition method. Under this method, results for reporting periods beginning after January 1, 2018 are presented under ASC 606, while prior period amounts are not adjusted and continue to be reported in accordance The Company enters into licensing agreements which are within the scope of ASC 606, under which it may exclusively license rights to research, develop, manufacture and commercialize its product candidates to third parties. The terms of these arrangements may include payment to the Company of one or more of the following: non-refundable, upfront license fees; reimbursement of certain costs; development, regulatory and commercial milestone payments; and royalties on net sales of licensed products. In determining the appropriate amount of revenue to be recognized as the Company fulfills its obligations under each of its agreements, the Company performs the following steps: (i) identification of the promised goods or services in the contract; (ii) determination of whether the promised goods or services are performance obligations, including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations; and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. As part of the accounting for these arrangements, the Company must use significant judgment to determine: (a) the number of performance obligations based on the determination under step (ii) above and (b) the transaction price under step (iii) above. The Company uses judgment to determine whether milestones or other variable consideration, except for royalties, should be included in the transaction price as described further below. The transaction price is allocated to each performance obligation on a relative stand-alone selling price basis, for which the Company recognizes revenue as or when the performance obligations under the contract are satisfied. Amounts received prior to revenue recognition are recorded as deferred revenue. Amounts expected to be recognized as revenue within the 12 months following the balance sheet date are classified as current portion of deferred revenue in the accompanying consolidated balance sheets. Amounts not expected to be recognized as revenue within the 12 months following the balance sheet date are classified as deferred revenue, net of current portion. Exclusive Licenses If the license to the Company’s intellectual property is determined to be distinct from the other promises or performance obligations identified in the arrangement, the Company recognizes revenue from non-refundable, upfront fees allocated to the license when the license is transferred to the customer and the customer is able to use and benefit from the license. In assessing whether a promise or performance obligation is distinct from the other promises, the Company considers factors such as the research, development, manufacturing and commercialization capabilities of the collaboration partner and the availability of the associated expertise in the general marketplace. In addition, the Company considers whether the collaboration partner can benefit from a promise for its intended purpose without the receipt of the remaining promise, whether the value of the promise is dependent on the unsatisfied promise, whether there are other vendors that could provide the remaining promise, and whether it is separately identifiable from the remaining promise. For licenses that are combined with other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. The measure of progress, and thereby periods over which revenue should be recognized, are subject to estimates by management and may change over the course of the research and development and licensing agreement. Such a change could have a material impact on the amount of revenue the Company records in future periods. Milestone Payments At the inception of each arrangement that includes development milestone payments, the Company evaluates whether the milestones are considered probable of being achieved and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the control of the Company or the licensee, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. The Company evaluates factors such as the scientific, clinical, regulatory, commercial, and other risks that must be overcome to achieve the particular milestone in making this assessment. There is considerable judgment involved in determining whether it is probable that a significant revenue reversal would not occur. At the end of each subsequent reporting period, the Company reevaluates the probability of achievement of all milestones subject to constraint and, if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenues and earnings in the period of adjustment. Royalties For arrangements that include sales-based royalties, including milestone payments based on a level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). Impact of Adoption The most significant change relates to the Company’s accounting for contingent milestone payments. Under ASC 605, the Company recognized revenue related to contingent milestone payments as the milestone was achieved, using the milestone method. Under ASC 606, the Company performs an assessment of the probability of milestone achievement at each reporting date, and determines whether the cumulative revenue related to the milestone is at risk of significant reversal. As a result of adopting ASC 606 on January 1, 2018, the Company did not record any cumulative changes in the current period, as the performance obligation related to the Agreement with EA Pharma was fully satisfied in 2012. Additionally, there was no difference in the revenue recognized or costs recorded in the six months ended June 30, 2018 as what would have been recognized or recorded under ASC 605. In September 2016, the FASB issued ASU 2016-15, “ Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (a consensus of the Emerging Issues Task Force) In May 2017, the FASB issued ASU 2017-09, “ Compensation – Stock Compensation (Topic 718), Scope of Modification Accounting,” Accounting pronouncements issued but not yet adopted In February 2016, the FASB issued ASU 2016-02, “ Leases (Topic 842)

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	2. Commitments and contingencies Operating lease commitments As of June 30, 2018, future minimum commitments under facility operating leases were $1,088,000. Rent expense recognized under the Company’s operating leases was $204,000 and $185,000 for the six months ended June 30, 2018 and 2017, respectively. Agreements with CROs As of June 30, 2018, the Company had various agreements with CROs for the conduct of specified research and development activities. Based on the terms of the respective agreements, the Company may be required to make future payments of up to $17.6 million to CROs upon the completion of contracted work. Other Commitments In connection with the spin-off of Albireo Limited from AstraZeneca in 2008 and associated transfer agreements, the Company became party to an assignment agreement between AstraZeneca and a named inventor on a patent related to elobixibat. In connection with this agreement, in April 2018, the Company was required to pay a one-time “launch fee” of $457,000.

Net Loss Per Share

Net Loss Per Share	6 Months Ended
	Jun. 30, 2018
Earnings Per Share [Abstract]
Net Loss Per Share	3. Net loss per share Basic net loss per share, or Basic EPS, is calculated by dividing the net loss by the weighted average number of shares of common stock outstanding. Diluted net loss per share, or Diluted EPS, is calculated by dividing the net loss by the weighted-average number of shares of common stock plus dilutive common stock equivalents outstanding. The following table sets forth the computation of Basic EPS and Diluted EPS (in thousands, except for share and per share data): Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 Basic and Diluted EPS: Numerator Net loss $ (14,603 ) $ (6,176 ) $ (16,222 ) $ (12,847 ) Denominator Weighted average number of shares 11,938,357 7,171,610 11,417,463 6,734,555 Basic and Diluted EPS $ (1.22 ) $ (0.86 ) $ (1.42 ) $ (1.91 ) The following outstanding common stock equivalents were excluded from the computation of Diluted EPS for the three and six months ended June 30, 2018 and 2017 because including them would have been anti-dilutive: For the Three Months Ended June 30, For the Six Months Ended June 30, 2018 2017 2018 2017 Options to purchase common stock 1,393,297 767,662 1,393,297 767,662

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2018
Income Tax Disclosure [Abstract]
Income taxes	4. Income taxes The Company did not record a tax provision or benefit for the three months or six months ended June 30, 2018 or 2017. The Company has continued to maintain a full valuation allowance against its net deferred tax assets. The Company has had an overall net operating loss position since its inception. On December 22, 2017, the SEC staff issued Staff Accounting Bulletin No. 118 (SAB 118), which provides guidance on accounting for the tax effects of the Tax Cuts and Jobs Act (TCJA). SAB 118 provides a measurement period that should not extend beyond one year from the TCJA enactment date for companies to complete the accounting under ASC Topic 740, Income Taxes

Stock-based Compensation

Stock-based Compensation	6 Months Ended
	Jun. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-based Compensation	5. Stock-based Compensation The Company recognized stock-based compensation expense for employees of $1.1 million and $1.4 million for the three months ended June 30, 2018 and 2017, respectively, and $2.2 million and $2.1 million for the six months ended June 30, 2018 and 2017, respectively. A summary of the outstanding stock options as of June 30, 2018 is as follows: Stock Options Outstanding Number of Shares Weighted Average Exercise Price Per Share Weighted Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (in thousands) Outstanding—December 31, 2017 1,035,361 $ 17.78 8.71 $ 11,896 Granted 486,050 $ 31.12 — $ — Expirations/forfeitures (42,491 ) $ 41.93 — $ — Exercises (60,345 ) $ 4.23 — $ — Outstanding—June 30, 2018 1,418,575 $ 21.94 8.47 $ 20,587 Exercisable—June 30, 2018 444,425 $ 15.72 7.03 $ 10,142 Vested or expected to vest at—June 30, 2018 1,399,153 $ 22.23 8.48 $ 19,917 Aggregate intrinsic value represents the difference between the estimated fair value of the underlying common stock and the exercise price of outstanding, in-the-money options. Options to purchase 19,422 shares of common stock are performance based and vest upon the date the Company files a drug approval application for its product candidate A4250 for any orphan indication, if such filing occurs prior to a specified date. This unvested performance-based option is excluded from the vested or expected to vest balance as of June 30, 2018. As of June 30, 2018, the total unrecognized compensation expense related to unvested options was $17.1 million, which the Company expects to recognize over a weighted average vesting period of 2.6 years. In determining the estimated fair value of the stock-based awards, the Company uses the Black-Scholes option pricing model and assumptions discussed below. Each of these inputs is subjective and generally requires significant judgment to determine. The fair value of stock option awards granted during the three and six months ended June 30, 2018 was estimated with the following assumptions: Three Months Ended June 30, 2018 Six Months Ended June 30, 2018 Price per share of common stock $30.68-$32.53 30.68-32.57 Expected term (in years) 5.5-6.0 5.3-6.0 Risk-free interest rate 2.8 2.6-2.8 Expected volatility 84.7-86.9 84.7-86.9 Dividend rate 0% 0%

Financings

Financings	6 Months Ended
	Jun. 30, 2018
Financings Disclosure [Abstract]
Financings	6. Financings At-the-Market Sales In October 2017, the Company entered into an at-the-market offering program Sales Agreement with Cowen and Company, LLC (Cowen) 24.2 million January 2018 Underwritten Public Offering On January 29, 2018, the Company completed an underwritten public offering of 2,265,500 shares of its common stock, at a price to public of $33.00 per share. The Company received net proceeds from this offering of $70.0 million, after deducting underwriting discounts, commission and offering expenses.

Summary of Significant Accoun13

Summary of Significant Accounting Policies and Basis of Presentation (Policies)	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Organization	Organization Albireo Pharma, Inc. (Parent), together with its direct and indirect subsidiaries (the Company), is a clinical-stage biopharmaceutical company focused on the development and commercialization of novel bile acid modulators to treat orphan pediatric liver diseases and other liver and gastrointestinal diseases and disorders. The Company’s clinical pipeline includes a Phase 3 product candidate, a Phase 2 product candidate, and elobixibat, which is approved in Japan for the treatment of chronic constipation. We also anticipate commencing a development program with elobixibat in nonalcoholic steatohepatitis or NASH. A4250, the Company’s Phase 3 lead product candidate, is in development initially for the treatment of patients with progressive familial intrahepatic cholestasis (PFIC), a rare, life-threatening genetic disorder affecting young children.
Basis of Presentation	Basis of presentation The accompanying unaudited Condensed Consolidated Financial Statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) for interim financial information, and the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements and should be read in conjunction with the audited consolidated financial statements and accompanying notes included in our Annual Report on Form 10-K for the fiscal year ended December 31, 2017. In the opinion of management, all adjustments (including normal recurring accruals) considered necessary for fair presentation have been included in the Condensed Consolidated Financial Statements. The results of operations for the three and six months ended June 30, 2018 are not necessarily indicative of the results that may be expected for the full fiscal year, any other interim period or any future fiscal year. The condensed consolidated financial statements are prepared on a basis consistent with prior periods except for the adoption of the new revenue recognition standard discussed below. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (ASC) and Accounting Standards Update (ASU) of the Financial Accounting Standards Board (FASB).
Principles of Consolidation	Principles of consolidation The accompanying Condensed Consolidated Financial Statements include the accounts of Parent and its direct or indirect wholly owned subsidiaries, Albireo Limited, Albireo AB, Elobix AB, Albireo, Inc., Albireo Security Corp. and Biodel UK Limited. All intercompany balances and transactions have been eliminated in consolidation.
Foreign Currency Translation	Foreign currency translation Functional and presentation currency Items included in the financial statements of each entity comprising the Company are measured using the currency of the primary economic environment in which the entity operates (the functional currency). The functional currency for Parent, Albireo, Inc. and Albireo Security Corp. is the U.S. Dollar (USD), the functional currency for Albireo Limited, Elobix AB and Biodel UK Limited is the Euro, and the functional currency for Albireo AB is the Swedish Krona (SEK). The Company consolidates its financial statements in USD. Transactions and balances Foreign currency transactions in each entity comprising the Company are remeasured into the functional currency of the entity using the exchange rates prevailing at the respective transaction dates. Foreign exchange gains and losses resulting from the settlement of such transactions and from the translation at period-end exchange rates of monetary assets and liabilities denominated in foreign currencies are recognized within Other (income) expense, net in the Condensed Consolidated Statements of Operations as part of operating expenses. The results and financial position of the Company that have a functional currency different from the USD are translated into the presentation currency as follows: a. assets and liabilities presented are translated at the closing exchange rate as of June 30, 2018 and December 31, 2017; b. income and expenses for each statement of comprehensive income (loss) are translated at the average exchange rate for the applicable period; c. significant transactions use the closing exchange rate on the date of the transaction; and d. all resulting exchange differences arising from such translations are recognized directly in other comprehensive income (loss) and presented as a separate component of equity.
Use of Estimates	Use of estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts of assets, liabilities, revenues and expenses reported in the financial statements and accompanying notes. Management must apply significant judgment in this process. On an ongoing basis, the Company evaluates its estimates and assumptions, including but not limited to accruals, deferred tax assets and royalty monetization liability estimated at fair value. Actual results could materially differ from these estimates.
Fair Value of Financial Instruments	Fair value of financial instruments When measuring the fair value of financial instruments, the Company evaluates valuation techniques such as the market approach, the income approach and the cost approach. A three-level valuation hierarchy, which prioritizes the inputs to valuation techniques that are used to measure fair value, is based upon whether such inputs are observable or unobservable. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect market assumptions made by the reporting entity. The three-level hierarchy for the inputs to valuation techniques is briefly summarized as follows: Level 1—Observable inputs such as quoted prices (unadjusted) for identical Level 2—Observable inputs such as quoted prices for similar Level 3—Unobservable inputs that reflect the reporting entity’s estimate of assumptions that market participants would use in pricing the asset or liability.
Research and Development Expenses	Research and development expenses Research and development costs are expensed as incurred and include primarily salaries, benefits and other staff-related costs; clinical trial and related clinical manufacturing costs; contract services and other outside costs. The Company’s nonclinical studies and clinical trials are performed by third-party contract research organizations (CROs). Some of these expenses are billed monthly for services performed, while others are billed based upon milestones achieved. For nonclinical studies, the significant factors used in estimating accruals include the percentage of work completed to date and contract milestones achieved. For clinical trial expenses, the significant factors used in estimating accruals include the number of patients enrolled and percentage of work completed to date or contract milestones achieved. The Company’s estimates are highly dependent upon the timeliness and accuracy of the data provided by the respective CROs regarding the status of the contracted activity, with adjustments made when deemed necessary.
Revenue Recognition	Revenue recognition In 2012, the Company entered into a license agreement (the Agreement) with EA Pharma Co., Ltd. (EA Pharma, formerly Ajinomoto Pharmaceuticals Co., Ltd.) to develop a select product candidate (elobixibat) for registration and subsequent commercialization in select markets. In conjunction with the Agreement, the Company granted EA Pharma an exclusive license to its intellectual property for development and commercialization activities in the designated field and territories. The Company is entitled to payments resulting from pharmaceutical ingredient or related procurement services if provided as part of a development plan. Revenue related to these payments is recorded on a net basis; in this instance, the Company acts as an agent, as it does not have discretion to change suppliers and does not perform any part of the services or manufacture of the subject pharmaceutical ingredients. The costs associated with these activities are netted against the related revenue in the condensed consolidated statements of operations. In 2012, EA Pharma made an upfront cash payment to the Company of €10.0 million under the Agreement. The parties amended the agreement in April 2016, pursuant to which EA Pharma made an additional cash payment to the Company of $8.0 million. As of June 30, 2018, the Company is eligible to receive an additional regulatory-based milestone payment under the Agreement of €4.3 million ($5.0 million based on the Euro to USD exchange rate as of June 30, 2018) if a specified regulatory event is achieved for elobixibat The Agreement will continue until the last royalty period for any product in the territory, which is defined as the period when there are no remaining patent rights or regulatory exclusivity in place for any products subject to royalties. EA Pharma may terminate the Agreement at will upon 180 days’ prior written notice to the Company. Either party may terminate the Agreement for the other party’s uncured material breach or insolvency and in certain other circumstances agreed to by the parties. The Company assessed this arrangement in accordance with Accounting Standards Codification (ASC) Topic 606, Revenue from Contracts with Customers Under the Agreement, in order to evaluate the appropriate transaction price, the Company determined that the upfront amount constituted the entirety of the consideration to be included in the transaction price as of the outset of the arrangement, which was allocated to the single performance obligation. At the outset of the arrangement, the transaction price included only the €10.0 million upfront consideration received, and was increased to include the $8.0 million received in conjunction with the 2016 amendment. The potential milestone payments were excluded from the transaction price, as all milestone amounts were fully constrained. In April 2013, December 2015, and October 2016, various development milestone events were achieved, and the Company recognized revenue related to these events; because the Company previously satisfied its performance obligation to deliver the license, the Company recorded these milestone payments as received. The Company will reevaluate the transaction price at the end of each reporting period and as other uncertain events are resolved or other changes in circumstances occur, and, if necessary, adjust its estimate of the transaction price. In January 2018, the Japanese Ministry of Health Labour and Welfare (MHLW) approved a new drug application filed by EA Pharma for elobixibat for the treatment of chronic constipation, for which the Company received a milestone payment of $11.2 million. Based on the regulatory approval, the Company determined that the milestone was no longer at risk of significant reversal. As such, because the single performance obligation had previously been satisfied, the Company recognized this amount in full in the first quarter of 2018 and there was no deferred revenue or contract asset as of June 30, 2018. Monetization of Future Royalties In December 2017, the Company executed the RIAA with HCR pursuant to which it sold to HCR the right to receive all royalties from sales in Japan and sales milestones achieved from any covered territory potentially payable to the Company under the Agreement, up to a specified maximum “cap” amount of $78.8 million, based on the funds the Company received from HCR to date. The Company received $44.5 million from HCR, net of certain transaction expenses, under the RIAA and the Company is eligible to receive an additional $15.0 million under the RIAA if a specified sales milestone is achieved for elobixibat in Japan. If the cap amount is reached, the Company will again become eligible to receive royalties from Japanese sales and sales milestones from covered territories for elobixibat from EA Pharma under the Agreement. The Company is obligated to make royalty interest payments to HCR under the RIAA only to the extent it receives future Japanese royalties, sales milestones or other specified payments from EA Pharma . Although the Company sold its rights to receive royalties from the sales of elobixibat in Japan, as a result of its ongoing involvement in the cash flows related to these royalties, the Company will continue to account for these royalties as revenue. The Company recorded the $44.5 million as a liability related to sale of future royalties (royalty obligation) in the balance sheet at June 30, 2018. The royalty obligation will be amortized using the effective interest rate method, based on the Company's best estimate of the time it will take to reach the capped amount. The following table shows the activity within the liability account during the period from the inception of the royalty transaction in December 2017 to June 30, 2018: June 30, 2018 (in thousands) Liability related to sale of future royalties—beginning balance $ — Proceeds from sale of future royalties, net 44,525 Unrealized foreign currency (gain)/loss on remeasurement of the liability 2,440 Foreign currency translation (gain)/loss (2,418 ) Accretion of interest expense on liability related to royalty monetzation 2,919 Liability related to sale of future royalties—ending balance $ 47,466 Less current portion classified within other current liabilities (730 ) Net ending Liability related to sale of future royalties $ 46,736 The Company records estimated royalties to accrued other until the payment is received from EA Pharma at which time the Company then remits payment to HCR. As royalties are remitted to HCR, the balance of the royalty obligation will be effectively repaid over the life of the RIAA. In order to determine the amortization of the royalty obligation, the Company is required to estimate the total amount of future royalty payments to be received and submitted to HCR, as noted above, based on the Company's best estimate of the time it will take to reach the cap amount. The sum of these amounts less the $44.5 million proceeds the Company received will be recorded as interest expense over the life of the royalty obligation. Since inception, the Company's estimate of its total interest expense resulted in a quarterly effective interest rate of approximately 4.15%. The Company periodically assesses the estimated royalty payments to HCR and to the extent such payments are greater or less than its initial estimates or the timing of such payments is materially different than its original estimates, the Company will prospectively adjust the accretion of interest on the royalty obligation. There are a number of factors that could materially affect the amount and the timing of royalty payments, most of which are not within the Company's control. Such factors include, but are not limited to, the rate of elobixibat prescriptions, the number of doses administered, the introduction of competing products, manufacturing or other delays, patent protection, adverse events that result in governmental health authority imposed restrictions on the use of the drug products, significant changes in foreign exchange rates as the royalties remitted to HCR are in U.S. dollars while sales of elobixibat are in Japanese yen, and sales never achieving forecasted numbers, which would result in reduced royalty payments, reduced non-cash royalty revenues and reduced non-cash interest expense over the life of the royalty obligation.
Loss Contingencies	Loss contingencies Loss contingencies are recorded as liabilities when it is probable that a liability has occurred and the amount of loss is reasonably estimable. Disclosure is required when there is a reasonable possibility that an ultimate loss will be material. Contingent liabilities are often resolved over long periods of time. Estimating probable losses requires analysis that often depends on judgments about potential actions by third parties, such as regulators.
Recently Adopted Accounting Pronouncements	Recently adopted accounting pronouncements Effective January 1, 2018, the Company adopted ASC Topic 606, Revenue from Contracts with Customers modified retrospective transition method. Under this method, results for reporting periods beginning after January 1, 2018 are presented under ASC 606, while prior period amounts are not adjusted and continue to be reported in accordance The Company enters into licensing agreements which are within the scope of ASC 606, under which it may exclusively license rights to research, develop, manufacture and commercialize its product candidates to third parties. The terms of these arrangements may include payment to the Company of one or more of the following: non-refundable, upfront license fees; reimbursement of certain costs; development, regulatory and commercial milestone payments; and royalties on net sales of licensed products. In determining the appropriate amount of revenue to be recognized as the Company fulfills its obligations under each of its agreements, the Company performs the following steps: (i) identification of the promised goods or services in the contract; (ii) determination of whether the promised goods or services are performance obligations, including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations; and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. As part of the accounting for these arrangements, the Company must use significant judgment to determine: (a) the number of performance obligations based on the determination under step (ii) above and (b) the transaction price under step (iii) above. The Company uses judgment to determine whether milestones or other variable consideration, except for royalties, should be included in the transaction price as described further below. The transaction price is allocated to each performance obligation on a relative stand-alone selling price basis, for which the Company recognizes revenue as or when the performance obligations under the contract are satisfied. Amounts received prior to revenue recognition are recorded as deferred revenue. Amounts expected to be recognized as revenue within the 12 months following the balance sheet date are classified as current portion of deferred revenue in the accompanying consolidated balance sheets. Amounts not expected to be recognized as revenue within the 12 months following the balance sheet date are classified as deferred revenue, net of current portion. Exclusive Licenses If the license to the Company’s intellectual property is determined to be distinct from the other promises or performance obligations identified in the arrangement, the Company recognizes revenue from non-refundable, upfront fees allocated to the license when the license is transferred to the customer and the customer is able to use and benefit from the license. In assessing whether a promise or performance obligation is distinct from the other promises, the Company considers factors such as the research, development, manufacturing and commercialization capabilities of the collaboration partner and the availability of the associated expertise in the general marketplace. In addition, the Company considers whether the collaboration partner can benefit from a promise for its intended purpose without the receipt of the remaining promise, whether the value of the promise is dependent on the unsatisfied promise, whether there are other vendors that could provide the remaining promise, and whether it is separately identifiable from the remaining promise. For licenses that are combined with other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. The measure of progress, and thereby periods over which revenue should be recognized, are subject to estimates by management and may change over the course of the research and development and licensing agreement. Such a change could have a material impact on the amount of revenue the Company records in future periods. Milestone Payments At the inception of each arrangement that includes development milestone payments, the Company evaluates whether the milestones are considered probable of being achieved and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the control of the Company or the licensee, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. The Company evaluates factors such as the scientific, clinical, regulatory, commercial, and other risks that must be overcome to achieve the particular milestone in making this assessment. There is considerable judgment involved in determining whether it is probable that a significant revenue reversal would not occur. At the end of each subsequent reporting period, the Company reevaluates the probability of achievement of all milestones subject to constraint and, if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenues and earnings in the period of adjustment. Royalties For arrangements that include sales-based royalties, including milestone payments based on a level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). Impact of Adoption The most significant change relates to the Company’s accounting for contingent milestone payments. Under ASC 605, the Company recognized revenue related to contingent milestone payments as the milestone was achieved, using the milestone method. Under ASC 606, the Company performs an assessment of the probability of milestone achievement at each reporting date, and determines whether the cumulative revenue related to the milestone is at risk of significant reversal. As a result of adopting ASC 606 on January 1, 2018, the Company did not record any cumulative changes in the current period, as the performance obligation related to the Agreement with EA Pharma was fully satisfied in 2012. Additionally, there was no difference in the revenue recognized or costs recorded in the six months ended June 30, 2018 as what would have been recognized or recorded under ASC 605. In September 2016, the FASB issued ASU 2016-15, “ Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (a consensus of the Emerging Issues Task Force) In May 2017, the FASB issued ASU 2017-09, “ Compensation – Stock Compensation (Topic 718), Scope of Modification Accounting,”
Accounting Pronouncements Issued but not Yet Adopted	Accounting pronouncements issued but not yet adopted In February 2016, the FASB issued ASU 2016-02, “ Leases (Topic 842)

Summary of Significant Accoun14

Summary of Significant Accounting Policies and Basis of Presentation (Tables)	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Schedule of Activity within Liability Account from Inception of Royalty Transaction	The following table shows the activity within the liability account during the period from the inception of the royalty transaction in December 2017 to June 30, 2018: June 30, 2018 (in thousands) Liability related to sale of future royalties—beginning balance $ — Proceeds from sale of future royalties, net 44,525 Unrealized foreign currency (gain)/loss on remeasurement of the liability 2,440 Foreign currency translation (gain)/loss (2,418 ) Accretion of interest expense on liability related to royalty monetzation 2,919 Liability related to sale of future royalties—ending balance $ 47,466 Less current portion classified within other current liabilities (730 ) Net ending Liability related to sale of future royalties $ 46,736

Net Income (Loss) Per Share (Ta

Net Income (Loss) Per Share (Tables)	6 Months Ended
	Jun. 30, 2018
Earnings Per Share [Abstract]
Summary of Computation of Basic EPS and Diluted EPS	The following table sets forth the computation of Basic EPS and Diluted EPS (in thousands, except for share and per share data): Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 Basic and Diluted EPS: Numerator Net loss $ (14,603 ) $ (6,176 ) $ (16,222 ) $ (12,847 ) Denominator Weighted average number of shares 11,938,357 7,171,610 11,417,463 6,734,555 Basic and Diluted EPS $ (1.22 ) $ (0.86 ) $ (1.42 ) $ (1.91 )
Summary of Outstanding Shares Excluded from Computation of Diluted EPS	The following outstanding common stock equivalents were excluded from the computation of Diluted EPS for the three and six months ended June 30, 2018 and 2017 because including them would have been anti-dilutive: For the Three Months Ended June 30, For the Six Months Ended June 30, 2018 2017 2018 2017 Options to purchase common stock 1,393,297 767,662 1,393,297 767,662

Stock-based Compensation (Table

Stock-based Compensation (Tables)	6 Months Ended
	Jun. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Outstanding Stock Options	A summary of the outstanding stock options as of June 30, 2018 is as follows: Stock Options Outstanding Number of Shares Weighted Average Exercise Price Per Share Weighted Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (in thousands) Outstanding—December 31, 2017 1,035,361 $ 17.78 8.71 $ 11,896 Granted 486,050 $ 31.12 — $ — Expirations/forfeitures (42,491 ) $ 41.93 — $ — Exercises (60,345 ) $ 4.23 — $ — Outstanding—June 30, 2018 1,418,575 $ 21.94 8.47 $ 20,587 Exercisable—June 30, 2018 444,425 $ 15.72 7.03 $ 10,142 Vested or expected to vest at—June 30, 2018 1,399,153 $ 22.23 8.48 $ 19,917
Summary of Estimated Fair Value of Stock Option Awards	The fair value of stock option awards granted during the three and six months ended June 30, 2018 was estimated with the following assumptions: Three Months Ended June 30, 2018 Six Months Ended June 30, 2018 Price per share of common stock $30.68-$32.53 30.68-32.57 Expected term (in years) 5.5-6.0 5.3-6.0 Risk-free interest rate 2.8 2.6-2.8 Expected volatility 84.7-86.9 84.7-86.9 Dividend rate 0% 0%

Summary of Significant Accoun17

Summary of Significant Accounting Policies and Basis of Presentation - Additional Information (Details) € in Millions	1 Months Ended			3 Months Ended		6 Months Ended			12 Months Ended
	Jan. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Apr. 30, 2016USD ($)	Jun. 30, 2018USD ($)	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)	Jun. 30, 2018EUR (€)	Jun. 30, 2017USD ($)	Dec. 31, 2012EUR (€)	Jun. 30, 2018EUR (€)
Summary Of Significant Accounting Policies [Line Items]
Revenue recognition, upfront cash payment received | €									€ 10
Revenue recognition milestone method additional revenue received after amendment			$ 8,000,000
Revenue recognition, milestone receivable				$ 5,000,000		$ 5,000,000				€ 4.3
Termination of royalty agreement written notice, period						180 days	180 days
Revenue recognition milestone received	$ 11,200,000
Deferred revenue or contract assets						$ 0
Proceeds from royalty agreement						44,525,000
Liability related to sale of future royalties				47,466,000		47,466,000
Operating expenses				11,136,000	$ 6,610,000	22,919,000		$ 12,708,000
Difference in Revenue Recognized or Costs Recorded due to Adoption of New Accounting Standards | ASU 606
Summary Of Significant Accounting Policies [Line Items]
Revenue recognized						0
Operating expenses						0
Royalty Interest Acquisition Agreement
Summary Of Significant Accounting Policies [Line Items]
Revenue recognition, milestone receivable		$ 78,800,000
Upfront consideration received | €							€ 10
Upfront consideration received in conjunction with 2015 amendment						8,000,000
Proceeds from royalty agreement		44,500,000
Liability related to sale of future royalties				$ 44,500,000		$ 44,500,000
Interest expense related to royalty agreement description						The sum of these amounts less the $44.5 million proceeds the Company received will be recorded as interest expense over the life of the royalty obligation. Since inception, the Company's estimate of its total interest expense resulted in a quarterly effective interest rate of approximately 4.15%.	The sum of these amounts less the $44.5 million proceeds the Company received will be recorded as interest expense over the life of the royalty obligation. Since inception, the Company's estimate of its total interest expense resulted in a quarterly effective interest rate of approximately 4.15%.
Quarterly effective interest rate				4.15%		4.15%				4.15%
Royalty Interest Acquisition Agreement | Sales Milestones
Summary Of Significant Accounting Policies [Line Items]
Revenue recognition, milestone receivable		$ 15,000,000

Summary of Significant Accoun18

Summary of Significant Accounting Policies and Basis of Presentation - Schedule of Activity within Liability Account from Inception of Royalty Transaction (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2018USD ($)
Accounting Policies [Abstract]
Proceeds from sale of future royalties, net	$ 44,525
Unrealized foreign currency (gain)/loss on remeasurement of the liability	2,440
Foreign currency translation (gain)/loss	(2,418)
Accretion of interest expense on liability related to royalty monetzation	2,919
Liability related to sale of future royalties—ending balance	47,466
Less current portion classified within other current liabilities	(730)
Net ending Liability related to sale of future royalties	$ 46,736

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($)	1 Months Ended	6 Months Ended
	Apr. 30, 2018	Jun. 30, 2018	Jun. 30, 2017
AstraZeneca
Loss Contingencies [Line Items]
One-time, launch fee payment	$ 457,000
CROs
Loss Contingencies [Line Items]
Agreement on leases future minimum payments upon completion of contracted work		$ 17,600,000
Operating Lease Commitments
Loss Contingencies [Line Items]
Future minimum commitments under facility operating leases		1,088,000
Rent expense		$ 204,000	$ 185,000

Net Loss Per Share - Summary of

Net Loss Per Share - Summary of Computation of Basic EPS and Diluted EPS (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Basic and Diluted EPS:
Net loss	$ (14,603)	$ (6,176)	$ (16,222)	$ (12,847)
Denominator
Weighted average number of shares used for basic and diluted EPS computation	11,938,357	7,171,610	11,417,463	6,734,555
Basic and Diluted EPS	$ (1.22)	$ (0.86)	$ (1.42)	$ (1.91)

Net Loss Per Share - Summary 21

Net Loss Per Share - Summary of Outstanding Shares Excluded from Computation of Diluted EPS (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net loss per share	1,393,297	767,662	1,393,297	767,662

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Income tax provisions or benefits	$ 0	$ 0	$ 0	$ 0

Stock-based Compensation - Addi

Stock-based Compensation - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 1.1	$ 1.4	$ 2.2	$ 2.1
Options, exercisable	444,425		444,425
Total unrecognized compensation expense related to unvested options	$ 17.1		$ 17.1
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average vesting period for unvested options			2 years 7 months 6 days
Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options, exercisable	19,422		19,422
Common Stock | Performance Based Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options, non vested	19,422		19,422

Stock-based Compensation - Summ

Stock-based Compensation - Summary of Outstanding Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Summary of the stock option activity
Number of Shares Outstanding, Beginning Balance	1,035,361
Number of Shares, Granted	486,050
Number of Shares, Expirations/forfeitures	(42,491)
Number of Shares, Exercises	(60,345)
Number of Shares Outstanding, Ending Balance	1,418,575	1,035,361
Number of Shares, Exercisable	444,425
Number of Shares, Vested or expected to vest	1,399,153
Weighted Average Exercise Price Per Share Outstanding, Beginning Balance	$ 17.78
Weighted Average Exercise Price Per Share, Granted	31.12
Weighted Average Exercise Price Per Share, Expirations/forfeitures	41.93
Weighted Average Exercise Price Per Share, Exercises	4.23
Weighted Average Exercise Price Per Share Outstanding, Ending Balance	21.94	$ 17.78
Weighted Average Exercise Price Per Share Exercisable	15.72
Weighted Average Exercise Price Per Share Vested or expected to vest	$ 22.23
Outstanding, Weighted Average Remaining Contractual Term (Years)	8 years 5 months 19 days	8 years 8 months 15 days
Exercisable, Weighted Average Remaining Contractual Term (Years)	7 years 10 days
Vested or expected to vest, Weighted Average Remaining Contractual Term (Years)	8 years 5 months 23 days
Outstanding options, Aggregate Intrinsic Value	$ 11,896
Outstanding options, Aggregate Intrinsic Value	20,587	$ 11,896
Exercisable options, Aggregate Intrinsic Value	10,142
Vested or expected to vest options, Aggregate Intrinsic Value	$ 19,917

Stock-based Compensation - Su25

Stock-based Compensation - Summary of Estimated Fair Value of Stock Option Awards (Details) - Employee Stock Option - $ / shares	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018
Stock Based Compensation [Line Items]
Risk-free interest rate	2.80%
Risk-free interest rate, minimum		2.60%
Risk-free interest rate, maximum		2.80%
Expected volatility, minimum	84.70%	84.70%
Expected volatility, maximum	86.90%	86.90%
Dividend rate	0.00%	0.00%
Minimum
Stock Based Compensation [Line Items]
Price per share of common stock	$ 30.68	$ 30.68
Expected term (in years)	5 years 6 months	5 years 3 months 18 days
Maximum
Stock Based Compensation [Line Items]
Price per share of common stock	$ 32.53	$ 32.57
Expected term (in years)	6 years	6 years

Financings - Additional Informa

Financings - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	Jan. 29, 2018	Feb. 28, 2018	Oct. 31, 2017
January 2018 Underwritten Public Offering [Member]
Financings [Line Items]
Number of shares issued in transaction	2,265,500
Sale of stock, price per share	$ 33
Proceeds from sale of stock	$ 70
Cowen | At-the-market Offering Program
Financings [Line Items]
Aggregate shares of common stock sold		728,862
Proceeds from issuance of common stock, net of offering expenses		$ 24.2
Cowen | At-the-market Offering Program | Maximum
Financings [Line Items]
Common stock to be offered and sold at sole discretion			$ 50