Albireo Pharma (ALBO) 10-K 6 Mar 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Mar. 01, 2019	Jun. 30, 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-K
Document Period End Date	Dec. 31, 2018
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Trading Symbol	albo
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 421.1
Entity Common Stock, Shares Outstanding		12,026,025

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 163,885	$ 53,231
Prepaid expenses and other assets	850	1,054
Other receivables	2,915	726
Total current assets	167,650	55,011
Property and equipment, net	187	178
Goodwill	17,260	17,260
Other noncurrent assets	369	775
Total assets	185,466	73,224
Current liabilities:
Trade payables	4,352	1,350
Accrued expenses	8,165	6,105
Other liabilities	308	474
Total current liabilities	12,825	7,929
Liability related to sale of future royalties	49,969
Long-term liabilities	35	42
Total liabilities	62,829	7,971
Stockholders' Equity:
Common stock, $0.01 par value per share - 30,000,000 authorized at December 31, 2018 and December 31, 2017; 11,969,928, and 8,902,784 issued and outstanding at December 31, 2018, and December 31, 2017	120	89
Additional paid in capital	214,694	114,522
Accumulated other comprehensive income	4,293	1,001
Accumulated deficit	(96,470)	(50,359)
Total stockholders' equity	122,637	65,253
Total liabilities and stockholders' equity	$ 185,466	$ 73,224

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 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	11,969,928	8,902,784
Common stock, shares outstanding	11,969,928	8,902,784

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Revenue	$ 12,740	$ 1
Operating expenses:
Research and development	31,732	12,991
General and administrative	18,061	15,246
Other operating (income) expense, net	837	(3,659)
Total operating expenses	50,630	24,578
Operating loss	(37,890)	(24,577)
Interest income (expense), net	(4,838)	40
Other non-operating income (expense), net	(3,363)	335
Net loss before income taxes	(46,091)	(24,202)
Income tax	20	212
Net loss	$ (46,111)	$ (24,414)
Net loss per share attributable to holders of common stock:
Net loss per share - basic and diluted	$ (3.94)	$ (3.12)
Weighted average shares outstanding - basic and diluted	11,702,785	7,819,302

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (46,111)	$ (24,414)
Other comprehensive loss:
Foreign currency translation adjustment	3,292	(495)
Other comprehensive income (loss)	3,292	(495)
Total comprehensive loss	$ (42,819)	$ (24,909)

Consolidated Statements of Shar

Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income	Accumulated Deficit	Total
Balance at beginning of period at Dec. 31, 2016	$ 63	$ 61,338	$ 1,496	$ (25,945)	$ 36,952
Balance (in shares) at Dec. 31, 2016	6,292,644
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share based compensation expense		3,700			3,700
Exercise of options	$ 1	384			385
Exercise of options, shares	50,309
Exercise of warrants		617			617
Exercise of warrants, shares	29,831
Issuance of shares	$ 25	48,483			48,508
Issuance of shares (in shares)	2,530,000
Other comprehensive income (loss)			(495)		(495)
Net loss				(24,414)	(24,414)
Balance at end of period at Dec. 31, 2017	$ 89	114,522	1,001	(50,359)	65,253
Balance (in shares) at Dec. 31, 2017	8,902,784
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share based compensation expense		5,546			5,546
Exercise of options	$ 1	506			$ 507
Exercise of options, shares	72,782				72,782
Issuance of shares	$ 30	94,120			$ 94,150
Issuance of shares (in shares)	2,994,362
Other comprehensive income (loss)			3,292		3,292
Net loss				(46,111)	(46,111)
Balance at end of period at Dec. 31, 2018	$ 120	$ 214,694	$ 4,293	$ (96,470)	$ 122,637
Balance (in shares) at Dec. 31, 2018	11,969,928

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net loss	$ (46,111)	$ (24,414)
Adjustments to reconcile net loss to net cash used in operating activities:
Non cash interest expense on liability related to royalty monetization	6,975
Accretion of debt discount and amortization of issuance costs		163
Depreciation and amortization	45	35
Gain from the sale of IPR&D		(3,500)
Change in fair value of financial instruments		(251)
Gain on sale of property, plant and equipment	(14)
Stock-based compensation expense	5,546	3,700
Unrealized foreign exchange (gain) loss	4,631	(1,107)
Changes in operating assets and liabilities:
Trade receivables	(597)	28
Prepaid expenses and other current assets	196	(467)
Other receivables	(1,703)	(339)
Other non current assets	403	(245)
Trade payables	3,171	263
Accrued expenses	854	(1,705)
Other liabilities and long-term liabilities	(198)	273
Net cash used in operating activities	(26,802)	(27,566)
Cash flows from investing activities:
Purchase of property, plant and equipment	(61)	(190)
Proceeds from sale of property, plant and equipment	14	4,500
Net cash used in investing activities	(47)	4,310
Cash flows from financing activities:
Proceeds from issuance of common stock, net of issuance costs	94,150	48,508
Proceeds from royalty agreement	44,525
Exercise of options	507	385
Payments of principal on borrowings		(3,055)
Net cash provided by financing activities	139,182	45,838
Effect of exchange rate changes on cash and cash equivalents	(1,679)	718
Net increase in cash and cash equivalents	110,654	23,300
Cash and cash equivalents - beginning of period	53,231	29,931
Cash and cash equivalents - end of period	$ 163,885	53,231
Supplemental disclosures of cash flow information:
Cash paid for interest		178
Kreos Warrants
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	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies and Basis of Presentation	1. Summary of significant accounting policies and basis of presentation Organization and Share Exchange 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, a Phase 2 product candidate, and elobixibat, which is approved in Japan for the treatment of chronic constipation. A4250, the Company’s Phase 3 lead product, 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 These Consolidated Financial Statements have been prepared in conformity with generally accepted accounting principles in the United States (U.S. GAAP). Any reference in these notes to applicable guidance is meant to refer to the authoritative U.S. GAAP as found in the Accounting Standards Codification (ASC) and Accounting Standards Update (ASU) of the Financial Accounting Standards Board (FASB). Any reference in these Consolidated Financial Statements to common stock or options or warrants to purchase shares of common stock of the Company means the common stock or options or warrants to purchase shares of common stock of Parent. Principles of consolidation The accompanying Consolidated Financial Statements include the accounts of Parent and its direct or indirect wholly owned subsidiaries. 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). 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 remeasurement at year-end exchange rates of monetary assets and liabilities denominated in foreign currencies are recognized within Other operating (income) expense, net except for changes related to the liability related to the sale of future royalties which are recorded in Other non-operating (income) expense, net in the Consolidated Statements of Operations. The results and financial position of the Company that have a functional currency different from the USD are translated as follows: a. assets and liabilities presented are translated at the closing exchange rate as of December 31, 2018 and 2017; b. income and expenses for the statements of operations and comprehensive loss are translated at average exchange rates that are relevant for the respective periods for which the income and expenses occurred; and c. significant transactions use the exchange rate on the date of the transaction; 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 U.S. 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 the accretion of interest on the monetization liability. Actual results could materially differ from these estimates. Segment information The Company’s entire business is managed by a single management team, which reports to the chief executive officer. The chief executive officer is the chief operating decision maker. The Company has determined it has one operating segment as its chief operating decision maker allocates resources and assesses the performance of the business at this level. Accordingly, the Company has one reporting segment, which is the research and development of novel treatments for liver and gastrointestinal diseases and disorders. Cash and cash equivalents The Company considers all short-term highly liquid investments with an original maturity at the date of purchase of three months or less to be cash equivalents. Concentration of risk Credit risk Financial instruments that potentially subject the Company to significant concentration of credit risk consist primarily of cash and cash equivalents. For banks and financial institutions, only independent financial institutions with a high credit rating are utilized. The Company’s current license agreement is with an established and reputable pharmaceutical company and, historically, the Company has not had any material collection risk related to its accounts receivable. Concentration of revenue and accounts receivable The Company generally does not require collateral or other security in support of accounts receivable. Allowances are provided for individual accounts receivable when the Company becomes aware of a customer’s inability to meet its financial obligations, such as in the case of bankruptcy, deterioration in the customer’s operating results or change in financial position. If circumstances related to a customer change, estimates of the recoverability of receivables would be further adjusted. The Company also considers broad factors in evaluating the sufficiency of its allowances for doubtful accounts, including the length of time receivables are past due, significant one-time events, creditworthiness of customers and historical experience. There is no allowance for doubtful accounts as of December 31, 2018 or 2017. Equipment, net Equipment is stated at historical cost less depreciation and consists of computers, furniture and fixtures, and other equipment. Depreciation is computed using a straight-line method over the estimated useful lives. Computers and other equipment purchased for less than $2,000 or the equivalent thereof are expensed immediately. Gains and losses on disposals of equipment are determined by comparing the proceeds with the carrying amount and are recognized within Other operating (income) expense, net in the Consolidated Statements of Operations. Impairment of long-lived assets Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. In such instances, the recoverability of assets to be held and used is measured first by a comparison of the carrying amount of an asset group to future undiscounted net cash flows expected to be generated by the assets. If such assets are considered to be impaired, an impairment loss would be recognized if the carrying amount of the asset exceeds the fair value of the asset. There were no impairments recorded for the years ended December 31, 2018 and 2017. 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 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). 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 December 31, 2018, the Company is eligible to receive an additional regulatory-based milestone payment under the Agreement of €4.3 million ($4.9 million based on the Euro to USD exchange rate as of December 31, 2018) if a specified regulatory event is achieved for elobixibat. The cash payments and any other payments for milestones and royalties from EA Pharma are non-refundable, non-creditable and not subject to set-off. 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 (ASC 606), and concluded that the contract counterparty, EA Pharma, is a customer. The Company identified the following material promises under the arrangement: (1) a sub-licensable and exclusive license to use the Company’s intellectual property and collaboration compounds to conduct development and commercialization activities in the designated fields and territories and (2) the technology transfer of the Albireo intellectual property and compound. Participation on the joint development committee (“JDC”) and joint commercialization committee (“JCC”) was determined to be quantitatively and qualitatively immaterial and therefore is excluded from the performance obligations. The license was determined to not be distinct from the technology transfer; as such, the Company determined that these promises should be combined into a single performance obligation. 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 either fully constrained or related to future sales-based royalties. 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 December 31, 2018. The Company recognizes the royalty revenue based on the estimated qualifying sales by EA Pharma each period. 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 retain 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). 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 for the year ending December 31, 2018: December 31, 2018 (in thousands) Liability related to sale of future royalties—beginning balance $ — Proceeds from sale of future royalties, net Unrealized foreign currency (gain)/loss on remeasurement of the liability Foreign currency translation (gain)/loss in other comprehensive income/(loss) (3,271) Accretion of interest expense on liability related to royalty monetization Repayment of the liability (924) Liability related to sale of future royalties—ending balance $ 50,546 Less current portion classified within other current liabilities (577) Net ending liability related to sale of future royalties $ 49,969 The Company records estimated royalties due for the current period in 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 and when milestones will be received. 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 4.27%. 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 and reduced non-cash interest expense over the life of the royalty obligation . To the extent future royalties result in an amount less than the liability, the Company is not obligated to fund any such shortfall. Stock-based compensation The Company accounts for stock-based compensation awards in accordance with FASB ASC Topic 718, Compensation—Stock Compensation (ASC 718). ASC 718 requires all stock-based payments, including grants of stock options, to be recognized in the consolidated statements of operations based on their respective fair values. The fair value of the Company’s stock options has been determined using the Black-Scholes option pricing model, which requires the input of subjective assumptions, including (i) the expected stock price volatility, (ii) the expected term of the award, (iii) the risk-free interest rate and (iv) expected dividends. For the years ended December 31, 2018 and December 31, 2017, due to the lack of historical and implied volatility data of the Company’s common stock and equivalents, the expected volatility has been estimated based on the historical volatilities of peer companies in the Company’s industry that are publicly traded. The Company selected companies that it considers to have comparable characteristics to the Company, including enterprise value, risk profiles and position within the industry and with historical share price information sufficient to meet the expected term of the stock options. The historical volatility data has been computed using the daily closing prices for the selected companies. Due to the lack of sufficient historical data, the Company used the “simplified” method, whereby the expected term equals the arithmetic average of the vesting term and the original contractual term of the award, to determine the expected term of stock options. The Company records compensation expense for service-based awards over the vesting period of the award on a straight-line basis. For awards with service and performance based conditions, compensation related to the performance-based vesting conditions is recognized when achievement of the performance condition is considered probable and the compensation expense related to the service condition is recorded using the accelerated method. Modifications to stock-based awards are treated as an exchange of the original award for a new award with total compensation equal to the grant-date fair value of the original award plus any incremental value of the modification. The incremental value is based on the excess of the fair value of the modified award over the fair value of the original award immediately before the modification. The Company has early adopted ASC 2018-07 “ Improvement to Nonemployee Share-based Payment Accounting” standard as of July 1, 2018, which allows the Company to continue to recognize the expense of stock options to former employees as current employees, provided that the non-employee is required to continue to provide services to the employer. Once these services are not substantive, the Company will account for the transaction as a severance arrangement with no future service requirement; therefore, any related compensation cost would be recognized immediately. Employee benefits Pension obligations The Company has defined contribution plans for its Sweden-based employees whereby the Company pays contributions to employee benefit or insurance plans on a mandatory, contractual or voluntary basis. The Company has no legal or constructive obligations to pay further contributions if the fund does not hold sufficient assets to pay all employees the benefits relating to employee service in the current and prior periods. The Company has no further payment obligations once the contributions have been paid. The contributions are recognized as employee benefit expense when they are due. Prepaid contributions are recognized as an asset to the extent that a cash refund or a reduction in the future payments is available. The Company paid $352,000 and $317,000 to the plans for the years ended December 31, 2018 and 2017, respectively. 401(k) The Company has a 401(k) retirement plan in which all U.S.-based employees are eligible to participate. The Company contributed $164,600 and $70,200 to the plan for the years ended December 31, 2018 and 2017, respectively. The Company matches employee contributions to the plan, on a per employee basis, up to 4% of each employee’s wages for the years ended December 31, 2018 and 2017. 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. Income taxes The Company accounts for income taxes in accordance with ASC 740, Income Taxes (ASC 740). Deferred income taxes are recorded for the expected tax consequences of temporary differences between the tax basis of assets and liabilities for financial reporting purposes and amounts recognized for income tax purposes. The Company records a valuation allowance to reduce its deferred tax assets to the amount of future tax benefit that is more likely than not to be realized. Income tax expense consists of taxes currently payable and changes in deferred tax assets and liabilities calculated according to local tax rules. Deferred tax assets and liabilities are based on temporary differences that arise between carrying values used for financial reporting purposes and amounts used for taxation purposes of assets and liabilities and the future tax benefits of tax loss carry forwards. A deferred tax asset is recognized only to the extent that it is more likely than not that future taxable profits will be available against which the asset can be utilized. Significant judgment is required in determining any valuation allowance recorded against deferred tax assets. In assessing the need for a valuation allowance, the Company considers all available evidence for each jurisdiction including past operating results, estimates of future taxable income and the feasibility of ongoing tax planning strategies. In the event that the Company changes its determination as to the amount of deferred tax assets that can be realized, the Company will adjust its valuation allowance with a corresponding impact to income tax expense in the period in which such determination is made. The amount of deferred tax provided is calculated using tax rates in effect at the balance sheet date. The impact of tax law changes is recognized in periods when the change is enacted. A two-step approach is applied pursuant to ASC 740 in the recognition and measurement of uncertain tax positions taken or expected to be taken in a tax return. The first step is to determine if the weight of available evidence indicates that it is more likely than not that the tax position will be sustained in an audit, including resolution of any related appeals or litigation processes. The second step is to measure the tax benefit as the largest amount that is more than 50% likely to be realized upon ultimate settlement. The Company’s policy is to recognize interest and penalty expenses associated with uncertain tax positions as a component of income tax expense in the Consolidated Statements of Operations. As of the years ended December 31, 2018 and 2017, the Company had no accrued interest or penalties related to uncertain tax positions and no amounts have been recognized in the Consolidated Statements of Operations. Net loss per share Basic net loss per share is calculated by dividing the net loss attributable to holders of common stock by the weighted average number of shares of common stock outstanding. Diluted net loss per share is calculated by dividing the net loss attributable to holders of common stock by the weighted-average number of shares of common stock outstanding. If the Company were in a net income position, diluted net income per share would be calculated by dividing the net income attributable to holders of common stock by the weighted-average number of shares of common stock plus dilutive common stock equivalents outstanding, including any dilutive effect from such shares. Goodwill and long-lived assets Goodwill is the excess of the purchase price in a business combination over the fair value of identifiable net assets acquired. Goodwill and certain other intangible assets having indefinite lives are not amortized to earnings, but instead are subject to periodic testing for impairment. Goodwill and indefinite-lived intangible assets are assessed at least annually, but also whenever events or changes in circumstances indicate the carrying values may not b

Fair Value Measurement

Fair Value Measurement	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value of Financial instruments	2. Fair value of financial instruments In measuring fair value, 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 instruments in active markets; Level 2—Observable inputs such as quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, or model-derived valuations whose significant inputs are observable for substantially the full term of the assets or liabilities; and Level 3—Unobservable inputs that reflect the reporting entity’s estimate of assumptions that market participants would use in pricing the asset or liability.

Equipment, Net

Equipment, Net	12 Months Ended
	Dec. 31, 2018
Property Plant And Equipment [Abstract]
Equipment, Net	3. Equipment, net Equipment, net consisted of the following (in thousands): December 31, December 31, 2018 2017 Cost: Equipment cost as of January 1, $ 334 $ 143 Additions 58 190 Exchange differences (2) 1 Equipment cost as of period end 390 334 Less: Accumulated depreciation as of January 1 (156) (122) Depreciation for the period (45) (35) Exchange differences (2) 1 Accumulated depreciation as of period end (203) (156) Total equipment, net $ 187 $ 178 Depreciation expense for the years ended December 31, 2018 and 2017 was $47,000 and $34,000, respectively.

Accrued Expenses

Accrued Expenses	12 Months Ended
	Dec. 31, 2018
Payables And Accruals [Abstract]
Accrued Expenses	4. Accrued expenses Accrued expenses consisted of the following (in thousands): December 31, December 31, 2018 2017 Accrued bonuses $ 2,295 $ 1,717 Accrued vacation pay 435 464 Accrued social security pay 214 217 Accrued professional fees 131 470 Accrued development costs 3,257 1,747 Accrued severance 356 152 Accrued other 1,477 1,338 Total accrued expenses $ 8,165 $ 6,105

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	5. Commitments and contingencies Operating lease commitments Parent is a party to an Office Lease Agreement with SHIGO 10 PO Owner LLC for approximately 5,116 rentable square feet in the building located at 10 Post Office Square, Boston, Massachusetts, which serves as Parent’s corporate headquarters. The initial term of the lease is 62 months beginning on March 1, 2017. Parent has the option to extend the lease one time for an additional 5-year period. Following an initial two-month rent abatement period, Parent is obligated to make monthly rent payments in an amount that began at $20,997 and escalates by approximately 2% annually for the term of the lease. In addition, Parent is responsible under the lease for specified costs and charges, including certain operating expense, utilities, taxes and insurance. Albireo AB is a party to a 36‑month building lease for approximately 5,100 square feet of office space in Gothenburg, Sweden. The lease does not have stated escalating rent clauses, except for changes in the Swedish Consumer Price Index (CPI). The current quarterly payment under the lease is SEK 329,358 ($36,780 based on the SEK to USD exchange rate as of December 31, 2018). The current term of the lease expires in February 2022, but renews automatically thereafter for consecutive three-year terms unless notice of nonrenewal is given by either party at least nine months prior to the end of the current term and subject to Albireo AB’s right to terminate the lease at any time upon six months’ notice. Subsequent to year end, the lease was renewed for an additional three year period (through November 2022), with quarterly payments of SEK 329,358 ($36,780 based on the SEK to USD exchange rate as of December 31, 2018). As of December 31, 2018, future minimum commitments under facility operating leases were $961,000. Year ended December 31, (in thousands) 2019 $ 333 2020 266 2021 271 2022 91 Total Minimum Commitments $ 961 Rent expense recognized under the Company’s operating leases was $403,000 and $394,000 for the years ended December 31, 2018 and 2017, respectively. Agreements with CROs As of December 31, 2018, the Company had various agreements with CROs for the conduct of specified research and development activities and, based on the terms of the respective agreements, may be required to make future payments of up to $24.3 million upon the completion of contracted work. Legal Contingency On February 19, 2019, we filed a complaint for breach of contract and breach of implied covenant of good faith and fair dealing against Ferring International Center S.A. (the “Respondent”) in the United States District Court for the Southern District of New York. In the complaint, we are seeking, among other things, compensatory damages of at least € 37 million. We have retained outside counsel under a contingency fee arrangement, and as a result, we will not incur attorneys’ fees for litigating the matter, but counsel will receive a contingent fee of 33 1/3% of the net recovery (after deduction of expenses) in the event a recovery is received. Due to their nature, it is difficult to predict the outcome, or the costs involved in any litigation. Furthermore, the Respondent may have significant resources and interest to litigate and therefore, although we have a contingency fee arrangement, this litigation could be protracted and may ultimately involve significant legal expenses. 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” payment of $457,000.

Goodwill

Goodwill	12 Months Ended
	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill Disclosure [Text Block]	6. Goodwill The following table summarizes the Company’s goodwill activity: (in thousands) Goodwill at December 31, 2016 $ 18,110 Purchasing accounting adjustment (850) Goodwill at December 31, 2017 $ 17,260 Purchasing accounting adjustment — Goodwill at December 31, 2018 $ 17,260

Net Loss Per Share

Net Loss Per Share	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Net Loss Per Share	7. Net loss per share Basic net loss per share, or Basic EPS, is calculated by dividing the net loss attributable to holders of common stock 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 attributable to holders of common stock by the weighted-average number of common stock outstanding. If the Company were in a net income position, Diluted EPS would be calculated by dividing the net income attributable to holders of common stock by the weighted-average number 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): December 31, 2018 2017 Basic and Diluted EPS: Numerator Net loss $ (46,111) $ (24,414) Denominator Weighted average number of shares outstanding 11,702,785 7,819,302 Basic and Diluted EPS $ (3.94) $ (3.12) The following weighted-average outstanding common stock equivalents were excluded from the computation of Diluted EPS for the periods presented because including them would have been anti-dilutive: Year Ended 2018 2017 Options to purchase common stock and RSUs 696,710 889,934

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income taxes	8. Income taxes Effects of the Tax Cuts and Job Act On December 22, 2017, The Tax Cuts and Job Act (the Tax Act) was signed into U.S. law. The Tax Act significantly changes the Internal Revenue Code of 1986, as amended (the Code). Changes under the new tax law include a reduction in the federal corporate tax rate from 34% to 21%, limitations or eliminations to certain tax deductions, and usage of tax benefits in the future. In December 2017, the SEC staff issued SAB 118 to address the application of GAAP in situations when a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of H.R.1. The Company recognized the provisional tax impacts related to deemed repatriated earnings and the revaluation of deferred tax assets and liabilities and included these amounts in its consolidated financial statements for the year ended December 31, 2017. The Company did not record any adjustments in the year ended December 31, 2018 to these provisional amounts that were material to its financial statements. As of December 31, 2018, the Company’s accounting treatment is complete. The Company has had an overall net operating loss position since its inception. For the years ended December 31, 2018 and 2017, the components of loss before income taxes were as follows (in thousands): Year Ended December 31, 2018 2017 U.S. $ (13,951) $ (2,031) Foreign (32,140) (22,171) Total $ (46,091) $ (24,202) The components of income tax (benefit) for the years ended December 31, 2018 and 2017 were as follows (in thousands): Year Ended December 31, 2018 2017 Current tax expense: Federal $ — $ (1) State 21 (12) Foreign (1) 225 Total $ 20 $ 212 Deferred tax benefit: Federal $ — $ — State — — Foreign — — Total $ — $ — Total provision for income taxes $ 20 $ 212 A reconciliation of the U.S. statutory income tax rate to the consolidated effective income tax rate was as follows: Year ended December 31, 2018 2017 U.S. statutory income tax rate 21 % 34 % Non-deductible interest expense — — Stock compensation (2) (2) U.S. taxation of foreign earnings (10) — State taxes, net of federal tax effect 2 — Change in valuation allowance (13) 125 Write off of disallowed recognized built in loss — (143) Change in U.S. tax rate — (4) Foreign tax rate differences 1 (11) Other items 1 1 Effective income tax rate 0.0 % 0.0 % Deferred taxes are recognized for temporary differences between the bases of assets and liabilities for financial statement and income tax purposes. The tax effect of temporary differences that give rise to significant portions of the deferred tax assets are as follows (in thousands): Year Ended December 31, 2018 2017 Deferred tax assets: Tax loss carryforwards $ 26,280 $ 21,653 Capitalized expenses — Research and development credits 200 127 Accrued expenses 520 295 Stock compensation 1,400 825 Interest carryforwards 100 — Other 50 35 Total gross deferred tax assets 28,550 22,935 Valuation allowance (28,520) (22,910) Total deferred tax assets $ 30 $ 25 Deferred tax liabilities: Intangible assets $ (30) $ 25 Temporary difference on financial instruments — Total deferred tax liabilities (30) 25 Net deferred tax assets $ — $ — A valuation allowance is recorded against deferred tax assets if it is more likely than not that some or all of the deferred tax assets will not be realized. Due to the uncertainty surrounding the realization of the favorable tax attributes in future returns, the Company has reserved against its deferred tax assets at December 31, 2018 and 2017. The Company had approximately $28.5 million and $22.9 million in valuation allowances recorded against its deferred tax assets as of December 31, 2018 and 2017, respectively. The Company recorded an expense of $5.6 million for the change in valuation allowance for the year ended December 31, 2018 and a benefit of $30.2 million for the change in valuation allowance for the year ended December 31, 2017 . As of December 31, 2018, deferred tax assets related to net operating loss (NOL) carryforwards were $26.3 million, which may be used subject to certain limitations to offset future taxable income, if any. The NOL includes approximately $1.4 million for U.S. federal tax purposes and $153.9 million for U.S. state tax purposes. Losses carryforwards generated prior to December 31, 2017 expire between 2025 and 2037. As part of the changes from the Tax Cuts and Jobs Act, Federal net operating losses generated for tax years beginning after December 31, 2017 no longer have an expiration period and can be used indefinitely. Additional NOL of approximately $75.9 million were generated in various non-U.S. jurisdictions and will not expire. A valuation allowance has been established on the NOL carryforwards as it is uncertain as to whether future taxable income will be generated to utilize such NOLs. As of December 31, 2018, the Company has federal research and development credit carryforwards of $73,000, which expire commencing in fiscal year 2028. The Company also has state research and development credit carryforwards of approximately $160,000, which expire commencing in fiscal 2022. A valuation allowance has been established on the research and development credits as it is uncertain as to whether future taxable income will be generated. Utilization of the NOL and credit carryforwards may be subject to a substantial annual limitation due to ownership change limitations that have occurred previously or that could occur in the future as provided by Section 382 of the Code and similar state and foreign provisions. These ownership changes may limit the amount of NOL and credit carryforwards that can be utilized annually to offset future taxable income and tax, respectively. In general, an ownership change, as defined by Code Section 382, results from transactions increasing the ownership of certain shareholders or public groups in the stock of a corporation by more than 50 percentage points over a three‑year period. During 2016, the Company completed an analysis to assess and concluded that an ownership change within the meaning of Code Section 382 occurred. The analysis has not yet been updated beyond 2016. As a result of the Tax Act, the Company has included certain foreign income related to its monetization of future royalties as taxable income in the United States. This income was offset by US net operating loss carryforwards. The Company’s policy is for any earnings of non-U.S. subsidiaries to be indefinitely invested outside the United States on the basis of estimates that future domestic cash generation will be sufficient to meet future domestic cash needs and the Company’s specific plans for reinvestment of those subsidiary earnings, if any. Uncertain tax positions The Company accounts for uncertain tax positions under the recognition and measurement criteria of ASC 740‑10. For those tax positions for which it is more likely than not that a tax benefit will be sustained, the Company records the largest amount of tax benefit with a greater than 50% likelihood of being realized upon settlement with a taxing authority that has full knowledge of all relevant information. If the Company does not believe that it is not more likely than not that a tax benefit will be sustained, no tax benefit is recognized. As of December 31, 2018 and 2017, no uncertain tax positions have been recorded. Interest and penalties related to the settlement of uncertain tax positions, if any, will be reflected in income tax expense. The Company did not recognize any interest or penalties associated with unrecognized tax benefits in the accompanying consolidated financial statements. The Company does not expect any material changes to the unrecognized benefits within 12 months of the reporting date. Due to existence of the valuation allowance, future changes in the Company’s unrecognized tax benefits will not impact its effective tax rate. The Company files U.S. federal and state tax returns and has determined that its major tax jurisdictions are the United States and Massachusetts, as well as the United Kingdom and Sweden. The Company’s tax returns may be examined for certain tax jurisdictions back to December 31, 2015.

Shareholders' Equity

Shareholders' Equity	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Shareholders' Equity	9. Stockholders’ equity Preferred Stock As of December 31, 2018, the Company has 50,000,000 shares of preferred stock authorized. There are no shares of preferred stock issued or outstanding. Financing 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) relating to the sale of shares of the Company’s common stock having an aggregate offering price of up to $50.0 million from time to time through Cowen, acting as its agent. In February 2018, the Company sold an aggregate of 728,862 shares of common stock pursuant to the Sales Agreement and received proceeds, net of offering expenses, of approximately $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 the public of $33.00 per share. The Company received net proceeds from this offering of $69.9 million, after deducting underwriting discounts, commission and offering expenses. May 2017 Underwritten Public Offering On May 30, 2017, the Company completed an underwritten public offering of 2,530,000 shares of its common stock, at a price to the public of $20.50 per share. The Company received net proceeds from this offering of $48.5 million, after deducting underwriting discounts, commissions and offering expenses.

Stock-based Compensation

Stock-based Compensation	12 Months Ended
	Dec. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-based Compensation	10. Stock-based Compensation On November 3, 2016, the Albireo Pharma, Inc. 2016 Equity Incentive Plan (the 2016 Equity Plan) was approved by the Company’s stockholders. The 2016 Equity Plan replaced Biodel’s 2010 Stock Incentive Plan, as amended (the 2010 Plan), in connection with completion of the Biodel Transaction. The 2016 Equity Plan authorized the issuance of up to 635,000 shares, plus up to 249,059 shares issued if awards outstanding under the 2010 Plan were cancelled, forfeited or expired on or after the Biodel Transaction. All stock options outstanding under the 2010 Plan remain in full force and effect pursuant to their terms and the terms of the 2010 Plan. On September 13, 2017, the Parent’s Board of Directors adopted the Albireo Pharma, Inc. 2017 Inducement Equity Incentive Plan (the 2017 Inducement Plan) without stockholder approval pursuant to Rule 5635(c)(4) of the Nasdaq Listing Rules. Pursuant to the 2017 Inducement Plan, Parent may grant stock options, stock awards and other stock-based awards for up to a total of 150,000 shares of common stock to new employees of the Company. On June 8, 2018, the Albireo Pharma, Inc. 2018 Equity Incentive Plan (the 2018 Equity Plan) was approved by the Company’s stockholders. The 2018 Equity Plan replaced the 2016 Equity Plan. The 2018 Equity Plan authorized the issuance of up to 1,200,000 shares, plus up to 1,078,870 shares issued if awards outstanding under the 2010 Plan, the 2016 Equity Plan, or 2017 Inducement Plan were cancelled, forfeited or expired. All stock options outstanding under the 2010 Plan, 2016 Equity Plan, or 2017 Inducement Plan remain in full force and effect pursuant to their terms and the terms of their respective plan. The Company recognized stock-based compensation expense in the accompanying Consolidated Statements of Operations as follows (in thousands): Year Ended December 31, 2018 2017 General and administrative $ 3,735 $ 3,406 Research and development 1,811 294 Total stock-based compensation $ 5,546 $ 3,700 A summary of the outstanding stock options as of December 31, 2018 is as follows: Stock Options Outstanding Weighted- Weighted- Average Average Remaining Aggregate Exercise Contractual Intrinsic Number of Price Per Term Value (in Shares Share (Years) thousands) Outstanding—December 31, 2017 1,035,361 $ 17.78 8.71 $ 11,896 Granted 608,750 $ 30.92 Expirations/forfeitures (201,825) $ 28.53 Exercises (72,782) $ 6.96 Outstanding—December 31, 2018 1,369,504 $ 22.34 8.06 $ 8,421 Exercisable—December 31, 2018 545,151 $ 15.54 6.71 $ 6,596 Vested or expected to vest at—December 31, 2018 1,350,082 $ 22.65 8.07 $ 7,964 Aggregate intrinsic value represents the difference between the 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 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 December 31, 2018. As of December 31, 2018, the total unrecognized compensation expense related to unvested options was $14.1 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 share option awards was estimated with the following assumptions: As of December 31, As of December 31, 2018 2017 Price per share of common stock $ 26.27 - 33.61 $ 17.05 - 26.12 Expected term (in years) 5.5 - 6.0 5.2 - 6.9 Risk-free interest rate 2.6 - 3.1 % 1.9 - 2.3 % Expected volatility 84.4 - 89.9 % 69.5 - 78.4 % Dividend rate 0 % 0 % The Company recorded additional stock-based compensation expense of $788,000 in general and administrative expenses in its consolidated statement of operations for the year ended December 31, 2017. The additional expense was attributable to the correction of an understatement of expense recorded for the year ended December 31, 2016 due to the use of incorrect service periods for stock options. Restricted Stock Units The Company grants restricted stock units (“RSUs”) to executive officers and employees from time to time. There is no direct cost to the recipients of RSUs, except for any applicable taxes. Each RSU award represents one share of common stock and each award vests 25% on the first anniversary and in equal quarterly installments thereafter. The costs of the awards, determined as the fair market value of the shares on the grant date, are expensed on a straight lined basis over the length of the award. A summary of outstanding RSU as of December 31, 2018 is as follows: Shares Weighted Non-vested and outstanding balance at December 31, 2017 — $ — Changes during the period: RSUs granted Non-vested and outstanding RSU balance at December 31, 2018 $ Employee Stock Purchase Plan In June of 2018, the Company’s Board of Directors adopted the 2018 Employee Stock Purchase Plan (the Plan) that allows eligible employees to purchase shares of its common stock at a discount through payroll deductions. The Plan was subsequently approved by shareholders, with 300,000 shares being available to be issued under the Plan. The Plan terms state implementation will be by a series of six-month offering periods, with a new offering period commencing on June 1 and December 1 of each year or the first business day thereafter. The initial Offering Period under the Plan began on December 1, 2018 and will close on May 31, 2019. The Plan is intended to qualify under the Internal Revenue Code of 1986, Section 423.

Long-term Debt

Long-term Debt	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Long-term Debt	11. Long-term debt Loan Facility The Company (in particular, Albireo Limited) executed a loan agreement (Loan Facility) with Kreos Capital IV (UK) Limited (Kreos UK) in December 2014. The Company paid $178,000 in interest on the Loan Facility for the year ended December 31, 2017. The debt was paid in full during 2017 and therefore there was no remaining debt discount as of December 31, 2017. Interest expense included $161,000 of discount accretion for the years ended December 31, 2017 respectively. In May 2017, Kreos Capital exercised the Replacement Kreos Warrants in full on a “cashless” basis. The number of shares of the Company’s common stock issued in the cashless exercise, 29,831 shares, was determined by a formula specified in the warrant document.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies and Basis of Presentation (Policies) 10K	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of presentation These Consolidated Financial Statements have been prepared in conformity with generally accepted accounting principles in the United States (U.S. GAAP). Any reference in these notes to applicable guidance is meant to refer to the authoritative U.S. GAAP as found in the Accounting Standards Codification (ASC) and Accounting Standards Update (ASU) of the Financial Accounting Standards Board (FASB). Any reference in these Consolidated Financial Statements to common stock or options or warrants to purchase shares of common stock of the Company means the common stock or options or warrants to purchase shares of common stock of Parent.
Principles of Consolidation	Principles of consolidation The accompanying Consolidated Financial Statements include the accounts of Parent and its direct or indirect wholly owned subsidiaries. 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). 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 remeasurement at year-end exchange rates of monetary assets and liabilities denominated in foreign currencies are recognized within Other operating (income) expense, net except for changes related to the liability related to the sale of future royalties which are recorded in Other non-operating (income) expense, net in the Consolidated Statements of Operations. The results and financial position of the Company that have a functional currency different from the USD are translated as follows: a. assets and liabilities presented are translated at the closing exchange rate as of December 31, 2018 and 2017; b. income and expenses for the statements of operations and comprehensive loss are translated at average exchange rates that are relevant for the respective periods for which the income and expenses occurred; and c. significant transactions use the exchange rate on the date of the transaction; 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 U.S. 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 the accretion of interest on the monetization liability. Actual results could materially differ from these estimates.
Segment Information	Segment information The Company’s entire business is managed by a single management team, which reports to the chief executive officer. The chief executive officer is the chief operating decision maker. The Company has determined it has one operating segment as its chief operating decision maker allocates resources and assesses the performance of the business at this level. Accordingly, the Company has one reporting segment, which is the research and development of novel treatments for liver and gastrointestinal diseases and disorders.
Cash and Cash Equivalents	Cash and cash equivalents The Company considers all short-term highly liquid investments with an original maturity at the date of purchase of three months or less to be cash equivalents.
Concentration of Risk	Concentration of risk Credit risk Financial instruments that potentially subject the Company to significant concentration of credit risk consist primarily of cash and cash equivalents. For banks and financial institutions, only independent financial institutions with a high credit rating are utilized. The Company’s current license agreement is with an established and reputable pharmaceutical company and, historically, the Company has not had any material collection risk related to its accounts receivable. Concentration of revenue and accounts receivable The Company generally does not require collateral or other security in support of accounts receivable. Allowances are provided for individual accounts receivable when the Company becomes aware of a customer’s inability to meet its financial obligations, such as in the case of bankruptcy, deterioration in the customer’s operating results or change in financial position. If circumstances related to a customer change, estimates of the recoverability of receivables would be further adjusted. The Company also considers broad factors in evaluating the sufficiency of its allowances for doubtful accounts, including the length of time receivables are past due, significant one-time events, creditworthiness of customers and historical experience. There is no allowance for doubtful accounts as of December 31, 2018 or 2017.
Equipment, Net	Equipment, net Equipment is stated at historical cost less depreciation and consists of computers, furniture and fixtures, and other equipment. Depreciation is computed using a straight-line method over the estimated useful lives. Computers and other equipment purchased for less than $2,000 or the equivalent thereof are expensed immediately. Gains and losses on disposals of equipment are determined by comparing the proceeds with the carrying amount and are recognized within Other operating (income) expense, net in the Consolidated Statements of Operations.
Impairment of long-lived Assets	Impairment of long-lived assets Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. In such instances, the recoverability of assets to be held and used is measured first by a comparison of the carrying amount of an asset group to future undiscounted net cash flows expected to be generated by the assets. If such assets are considered to be impaired, an impairment loss would be recognized if the carrying amount of the asset exceeds the fair value of the asset. There were no impairments recorded for the years ended December 31, 2018 and 2017.
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 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). 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 December 31, 2018, the Company is eligible to receive an additional regulatory-based milestone payment under the Agreement of €4.3 million ($4.9 million based on the Euro to USD exchange rate as of December 31, 2018) if a specified regulatory event is achieved for elobixibat. The cash payments and any other payments for milestones and royalties from EA Pharma are non-refundable, non-creditable and not subject to set-off. 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 (ASC 606), and concluded that the contract counterparty, EA Pharma, is a customer. The Company identified the following material promises under the arrangement: (1) a sub-licensable and exclusive license to use the Company’s intellectual property and collaboration compounds to conduct development and commercialization activities in the designated fields and territories and (2) the technology transfer of the Albireo intellectual property and compound. Participation on the joint development committee (“JDC”) and joint commercialization committee (“JCC”) was determined to be quantitatively and qualitatively immaterial and therefore is excluded from the performance obligations. The license was determined to not be distinct from the technology transfer; as such, the Company determined that these promises should be combined into a single performance obligation. 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 either fully constrained or related to future sales-based royalties. 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 December 31, 2018. The Company recognizes the royalty revenue based on the estimated qualifying sales by EA Pharma each period.
Monetization of Future Royalties	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 retain 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). 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 for the year ending December 31, 2018: December 31, 2018 (in thousands) Liability related to sale of future royalties—beginning balance $ — Proceeds from sale of future royalties, net Unrealized foreign currency (gain)/loss on remeasurement of the liability Foreign currency translation (gain)/loss in other comprehensive income/(loss) (3,271) Accretion of interest expense on liability related to royalty monetization Repayment of the liability (924) Liability related to sale of future royalties—ending balance $ 50,546 Less current portion classified within other current liabilities (577) Net ending liability related to sale of future royalties $ 49,969 The Company records estimated royalties due for the current period in 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 and when milestones will be received. 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 4.27%. 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 and reduced non-cash interest expense over the life of the royalty obligation . To the extent future royalties result in an amount less than the liability, the Company is not obligated to fund any such shortfall.
Stock-based Compensation	Stock-based compensation The Company accounts for stock-based compensation awards in accordance with FASB ASC Topic 718, Compensation—Stock Compensation (ASC 718). ASC 718 requires all stock-based payments, including grants of stock options, to be recognized in the consolidated statements of operations based on their respective fair values. The fair value of the Company’s stock options has been determined using the Black-Scholes option pricing model, which requires the input of subjective assumptions, including (i) the expected stock price volatility, (ii) the expected term of the award, (iii) the risk-free interest rate and (iv) expected dividends. For the years ended December 31, 2018 and December 31, 2017, due to the lack of historical and implied volatility data of the Company’s common stock and equivalents, the expected volatility has been estimated based on the historical volatilities of peer companies in the Company’s industry that are publicly traded. The Company selected companies that it considers to have comparable characteristics to the Company, including enterprise value, risk profiles and position within the industry and with historical share price information sufficient to meet the expected term of the stock options. The historical volatility data has been computed using the daily closing prices for the selected companies. Due to the lack of sufficient historical data, the Company used the “simplified” method, whereby the expected term equals the arithmetic average of the vesting term and the original contractual term of the award, to determine the expected term of stock options. The Company records compensation expense for service-based awards over the vesting period of the award on a straight-line basis. For awards with service and performance based conditions, compensation related to the performance-based vesting conditions is recognized when achievement of the performance condition is considered probable and the compensation expense related to the service condition is recorded using the accelerated method. Modifications to stock-based awards are treated as an exchange of the original award for a new award with total compensation equal to the grant-date fair value of the original award plus any incremental value of the modification. The incremental value is based on the excess of the fair value of the modified award over the fair value of the original award immediately before the modification. The Company has early adopted ASC 2018-07 “ Improvement to Nonemployee Share-based Payment Accounting” standard as of July 1, 2018, which allows the Company to continue to recognize the expense of stock options to former employees as current employees, provided that the non-employee is required to continue to provide services to the employer. Once these services are not substantive, the Company will account for the transaction as a severance arrangement with no future service requirement; therefore, any related compensation cost would be recognized immediately.
Employee Benefits	Employee benefits Pension obligations The Company has defined contribution plans for its Sweden-based employees whereby the Company pays contributions to employee benefit or insurance plans on a mandatory, contractual or voluntary basis. The Company has no legal or constructive obligations to pay further contributions if the fund does not hold sufficient assets to pay all employees the benefits relating to employee service in the current and prior periods. The Company has no further payment obligations once the contributions have been paid. The contributions are recognized as employee benefit expense when they are due. Prepaid contributions are recognized as an asset to the extent that a cash refund or a reduction in the future payments is available. The Company paid $352,000 and $317,000 to the plans for the years ended December 31, 2018 and 2017, respectively. 401(k) The Company has a 401(k) retirement plan in which all U.S.-based employees are eligible to participate. The Company contributed $164,600 and $70,200 to the plan for the years ended December 31, 2018 and 2017, respectively. The Company matches employee contributions to the plan, on a per employee basis, up to 4% of each employee’s wages for the years ended December 31, 2018 and 2017.
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.
Income Taxes	Income taxes The Company accounts for income taxes in accordance with ASC 740, Income Taxes (ASC 740). Deferred income taxes are recorded for the expected tax consequences of temporary differences between the tax basis of assets and liabilities for financial reporting purposes and amounts recognized for income tax purposes. The Company records a valuation allowance to reduce its deferred tax assets to the amount of future tax benefit that is more likely than not to be realized. Income tax expense consists of taxes currently payable and changes in deferred tax assets and liabilities calculated according to local tax rules. Deferred tax assets and liabilities are based on temporary differences that arise between carrying values used for financial reporting purposes and amounts used for taxation purposes of assets and liabilities and the future tax benefits of tax loss carry forwards. A deferred tax asset is recognized only to the extent that it is more likely than not that future taxable profits will be available against which the asset can be utilized. Significant judgment is required in determining any valuation allowance recorded against deferred tax assets. In assessing the need for a valuation allowance, the Company considers all available evidence for each jurisdiction including past operating results, estimates of future taxable income and the feasibility of ongoing tax planning strategies. In the event that the Company changes its determination as to the amount of deferred tax assets that can be realized, the Company will adjust its valuation allowance with a corresponding impact to income tax expense in the period in which such determination is made. The amount of deferred tax provided is calculated using tax rates in effect at the balance sheet date. The impact of tax law changes is recognized in periods when the change is enacted. A two-step approach is applied pursuant to ASC 740 in the recognition and measurement of uncertain tax positions taken or expected to be taken in a tax return. The first step is to determine if the weight of available evidence indicates that it is more likely than not that the tax position will be sustained in an audit, including resolution of any related appeals or litigation processes. The second step is to measure the tax benefit as the largest amount that is more than 50% likely to be realized upon ultimate settlement. The Company’s policy is to recognize interest and penalty expenses associated with uncertain tax positions as a component of income tax expense in the Consolidated Statements of Operations. As of the years ended December 31, 2018 and 2017, the Company had no accrued interest or penalties related to uncertain tax positions and no amounts have been recognized in the Consolidated Statements of Operations.
Net loss per share	Net loss per share Basic net loss per share is calculated by dividing the net loss attributable to holders of common stock by the weighted average number of shares of common stock outstanding. Diluted net loss per share is calculated by dividing the net loss attributable to holders of common stock by the weighted-average number of shares of common stock outstanding. If the Company were in a net income position, diluted net income per share would be calculated by dividing the net income attributable to holders of common stock by the weighted-average number of shares of common stock plus dilutive common stock equivalents outstanding, including any dilutive effect from such shares.
Goodwill and Long-Lived Assets	Goodwill and long-lived assets Goodwill is the excess of the purchase price in a business combination over the fair value of identifiable net assets acquired. Goodwill and certain other intangible assets having indefinite lives are not amortized to earnings, but instead are subject to periodic testing for impairment. Goodwill and indefinite-lived intangible assets are assessed at least annually, but also whenever events or changes in circumstances indicate the carrying values may not be recoverable. Factors that could trigger an impairment review, include: (a) significant underperformance relative to historical or projected future operating results; (b) significant changes in the manner of or use of the acquired assets or the strategy for the Company’s overall business; (c) significant negative industry or economic trends; (d) significant decline in the Company’s stock price for a sustained period; and (e) a decline in the Company’s market capitalization below net book value. The Company conducts an impairment assessment on October 1 each year taking a qualitative evaluation approach to determine if there are any adverse market factors or changes in circumstances indicating that the carrying value of goodwill may not be recoverable. If it is more likely than not that an impairment exists, the Company performs a quantitative test which compares the fair value to the net carrying value, and records an impairment of goodwill to the extent that the net carrying value exceeds the fair value. Assessment for possible impairment of long-lived assets is based on the Company’s ability to recover the carrying value of the long-lived asset from the expected future pre-tax cash flows. The expected future pre-tax cash flows are estimated based on historical experience, knowledge and market data. Estimates of future cash flows require the Company to make assumptions and to apply judgment, including forecasting future sales and expenses and estimating the useful lives of assets. If the expected future cash flows related to a long-lived asset are less than the asset’s carrying value, an impairment charge is recognized for the difference between the estimated fair value and the carrying value.
Gain on Sale of IPR&D	Gain on Sale of IPR&D In October 2017, the Company entered into an asset purchase agreement pursuant to which it sold IPR&D for $4.5 million, which resulted in a gain recorded in other operating income.
Recently adopted accounting pronouncements	Recently adopted accounting pronouncements In June 2018, the FASB issued, ASC 2018-07 “ Improvement to Nonemployee Share-based Payment Accounting”. Under the new standard, companies are no longer required to value non-employee awards differently from employee awards. This standard is effective for fiscal years beginning after December 15, 2018, including interim periods within that fiscal year. The Company has early adopted this standard as of July 1, 2018 and determined there was no impact on the date of adoption to the Company’s condensed consolidated financial statements. Effective January 1, 2018, the Company adopted ASC Topic 606, Revenue from Contracts with Customers , using the 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 with ASC 605. This standard applies to all contracts with customers, except for contracts that are within the scope of other standards, such as leases, insurance, collaboration arrangements and financial instruments. Under ASC 606, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of ASC 606, the entity performs the following five step analysis (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The Company only applies the five-step analysis to contracts when it is probable that the entity will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within each contract, determines those that are performance obligations, and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. 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. 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),” which changes how certain cash receipts and cash payments are presented and classified in the statement of cash flows. The new standard is effective for fiscal years beginning after December 15, 2017 and for interim periods therein. The Company has adopted this standard as of January 1, 2018 and determined there is no impact of this standard on the Company’s consolidated financial statements as of the date of the adoption. In May 2017, the FASB issued ASU 2017‑09, “ Compensation – Stock Compensation (Topic 718), Scope of Modification Accounting,” (ASC 718), which amends the scope of modification accounting for share-based payment arrangements and provides guidance on the types of changes to the terms or conditions of share-based payment awards to which an entity would be required to apply modification accounting under ASC 718. The new standard is effective for fiscal years beginning after December 15, 2017 and for interim periods therein. The Company has adopted this standard as of January 1, 2018 and determined there is minimal impact on the Company’s consolidated financial statements
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) .” The new standard establishes a right-of-use (ROU) model that requires a lessee to record a ROU asset and a lease liability on the balance sheet for all leases with terms longer than 12 months. Leases will be classified as either finance or operating, with classification affecting the pattern of expense recognition in the income statement. The new standard is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. A modified retrospective transition approach is required for lessees for capital and operating leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. In August, another method of adoption was issued which provides an alternative to the modified retrospective transition method and allows companies to forgo the retrospective reporting requirements by recognizing a cumulative effect adjustment to the opening balance of retained earnings upon adoption in 2019. The Company will adopt the standard using the additional transition method introduced by ASU 2018-11. The Company completed its scoping assessment and determined that there are a limited number of leases that will be impacted by the new standard. While the Company is still in the process of determining the effect that the new standard will have on its consolidated financial statements and related disclosures based on our existing operating lease portfolio, the Company will be recognizing additional assets and corresponding liabilities on its consolidated balance sheet.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies and Basis of Presentation (Tables)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Schedule of Activity within Liability Account from Inception of Royalty Transaction	December 31, 2018 (in thousands) Liability related to sale of future royalties—beginning balance $ — Proceeds from sale of future royalties, net Unrealized foreign currency (gain)/loss on remeasurement of the liability Foreign currency translation (gain)/loss in other comprehensive income/(loss) (3,271) Accretion of interest expense on liability related to royalty monetization Repayment of the liability (924) Liability related to sale of future royalties—ending balance $ 50,546 Less current portion classified within other current liabilities (577) Net ending liability related to sale of future royalties $ 49,969

Equipment, Net (Tables)

Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2018
Property Plant And Equipment [Abstract]
Summary of Equipment, Net	December 31, December 31, 2018 2017 Cost: Equipment cost as of January 1, $ 334 $ 143 Additions 58 190 Exchange differences (2) 1 Equipment cost as of period end 390 334 Less: Accumulated depreciation as of January 1 (156) (122) Depreciation for the period (45) (35) Exchange differences (2) 1 Accumulated depreciation as of period end (203) (156) Total equipment, net $ 187 $ 178

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2018
Payables And Accruals [Abstract]
Summary of Accrued Expenses	December 31, December 31, 2018 2017 Accrued bonuses $ 2,295 $ 1,717 Accrued vacation pay 435 464 Accrued social security pay 214 217 Accrued professional fees 131 470 Accrued development costs 3,257 1,747 Accrued severance 356 152 Accrued other 1,477 1,338 Total accrued expenses $ 8,165 $ 6,105

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Schedule of Future Minimum Commitments under Facility Operating Leases	Year ended December 31, (in thousands) 2019 $ 333 2020 266 2021 271 2022 91 Total Minimum Commitments $ 961

Goodwill (Tables)

Goodwill (Tables)	12 Months Ended
	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule Of Goodwill [Text Block]	(in thousands) Goodwill at December 31, 2016 $ 18,110 Purchasing accounting adjustment (850) Goodwill at December 31, 2017 $ 17,260 Purchasing accounting adjustment — Goodwill at December 31, 2018 $ 17,260

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	12 Months Ended
	Dec. 31, 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): December 31, 2018 2017 Basic and Diluted EPS: Numerator Net loss $ (46,111) $ (24,414) Denominator Weighted average number of shares outstanding 11,702,785 7,819,302 Basic and Diluted EPS $ (3.94) $ (3.12)
Summary of Outstanding Shares Excluded from Computation of Diluted EPS	Year Ended 2018 2017 Options to purchase common stock and RSUs 696,710 889,934

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Schedule of Components of Loss Before Income Taxes	Year Ended December 31, 2018 2017 U.S. $ (13,951) $ (2,031) Foreign (32,140) (22,171) Total $ (46,091) $ (24,202)
Schedule of Components of Income Tax (Benefit)	Year Ended December 31, 2018 2017 Current tax expense: Federal $ — $ (1) State 21 (12) Foreign (1) 225 Total $ 20 $ 212 Deferred tax benefit: Federal $ — $ — State — — Foreign — — Total $ — $ — Total provision for income taxes $ 20 $ 212
Schedule of Reconciliations of Statutory Income Tax Rate to Consolidated Effective Income Tax Rate	Year ended December 31, 2018 2017 U.S. statutory income tax rate 21 % 34 % Non-deductible interest expense — — Stock compensation (2) (2) U.S. taxation of foreign earnings (10) — State taxes, net of federal tax effect 2 — Change in valuation allowance (13) 125 Write off of disallowed recognized built in loss — (143) Change in U.S. tax rate — (4) Foreign tax rate differences 1 (11) Other items 1 1 Effective income tax rate 0.0 % 0.0 %
Schedule of Tax Effect of Temporary Differences To Significant Portions of Deferred Tax Assets	Year Ended December 31, 2018 2017 Deferred tax assets: Tax loss carryforwards $ 26,280 $ 21,653 Capitalized expenses — Research and development credits 200 127 Accrued expenses 520 295 Stock compensation 1,400 825 Interest carryforwards 100 — Other 50 35 Total gross deferred tax assets 28,550 22,935 Valuation allowance (28,520) (22,910) Total deferred tax assets $ 30 $ 25 Deferred tax liabilities: Intangible assets $ (30) $ 25 Temporary difference on financial instruments — Total deferred tax liabilities (30) 25 Net deferred tax assets $ — $ —

Stock-based Compensation (Table

Stock-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of stock-based compensation expense	Year Ended December 31, 2018 2017 General and administrative $ 3,735 $ 3,406 Research and development 1,811 294 Total stock-based compensation $ 5,546 $ 3,700
Summary of outstanding stock options	Stock Options Outstanding Weighted- Weighted- Average Average Remaining Aggregate Exercise Contractual Intrinsic Number of Price Per Term Value (in Shares Share (Years) thousands) Outstanding—December 31, 2017 1,035,361 $ 17.78 8.71 $ 11,896 Granted 608,750 $ 30.92 Expirations/forfeitures (201,825) $ 28.53 Exercises (72,782) $ 6.96 Outstanding—December 31, 2018 1,369,504 $ 22.34 8.06 $ 8,421 Exercisable—December 31, 2018 545,151 $ 15.54 6.71 $ 6,596 Vested or expected to vest at—December 31, 2018 1,350,082 $ 22.65 8.07 $ 7,964
Schedule of fair value assumptions of share option awards	As of December 31, As of December 31, 2018 2017 Price per share of common stock $ 26.27 - 33.61 $ 17.05 - 26.12 Expected term (in years) 5.5 - 6.0 5.2 - 6.9 Risk-free interest rate 2.6 - 3.1 % 1.9 - 2.3 % Expected volatility 84.4 - 89.9 % 69.5 - 78.4 % Dividend rate 0 % 0 %
Summary of outstanding RSUs	Shares Weighted Non-vested and outstanding balance at December 31, 2017 — $ — Changes during the period: RSUs granted Non-vested and outstanding RSU balance at December 31, 2018 $

Summary of Significant Accoun_4

Summary of Significant Accounting Policies and Basis of Presentation - through Impairment (Details)	12 Months Ended
	Dec. 31, 2018USD ($)segment	Dec. 31, 2017USD ($)
Segment information
Number of operating segments | segment	1
Number of reportable segments | segment	1
Concentration of revenue and accounts receivable
Allowance for doubtful accounts	$ 0	$ 0
Equipment, net
Maximum value of computers and other equipment expensed at purchase and not capitalized	2,000
Impairment of long-lived assets
Impairment of long-lived assets	$ 0	$ 0

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Revenue (Details) $ in Thousands, € in Millions	1 Months Ended	3 Months Ended	12 Months Ended
	Apr. 30, 2016USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2012EUR (€)	Dec. 31, 2018EUR (€)	Dec. 31, 2018USD ($)
Disaggregation of Revenue [Line Items]
Revenue			$ 12,740	$ 1
Deferred revenue							$ 0
Contract asset							0
EA Pharma | Milestone Consideration Under Agreement
Disaggregation of Revenue [Line Items]
Revenue		$ 11,200
EA Pharma | License Agreement | Milestone Consideration Under Agreement
Disaggregation of Revenue [Line Items]
Contract asset						€ 4.3	$ 4,900
EA Pharma | Original license agreement | Upfront Consideration Under Agreement
Disaggregation of Revenue [Line Items]
Upfront payment received | €					€ 10
EA Pharma | License agreement amendment | Upfront Consideration Under Agreement
Disaggregation of Revenue [Line Items]
Upfront payment received	$ 8,000

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Monetization of future royalties (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018
Summary Of Significant Accounting Policies
Proceeds from royalty agreement		$ 44,525
Milestone payment receivable		0
Monetization Of Future Royalties [Abstract]
Proceeds from sale of future royalties, net		44,525
Unrealized foreign currency (gain) loss on remeasurement of the liability		3,241
Foreign currency translation (gain)/loss in other comprehensive income/(loss)		(3,271)
Accretion of interest expense on liability related to royalty monetization		6,975
Repayment of the liability		(924)
Liability related to sale of future royalties - ending balance		50,546
Less current portion classified within other current liabilities		(577)
Liability related to sale of future royalties		$ 49,969
Royalty Interest Acquisition Agreement
Monetization Of Future Royalties [Abstract]
Quarterly effective interest rate		4.27%
HCR | Royalty Interest Acquisition Agreement
Summary Of Significant Accounting Policies
Maximum royalties under monetization agreement	$ 78,800
Proceeds from royalty agreement	44,500
HCR | Royalty Interest Acquisition Agreement | Milestone Consideration Under Agreement
Summary Of Significant Accounting Policies
Milestone payment receivable	$ 15,000

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Employee benefits, taxes and other (Details) - USD ($)	1 Months Ended	12 Months Ended
	Oct. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense [Abstract]
Accrued interest or penalties related to uncertain tax positions		$ 0	$ 0
Amount of interest or penalties associated with uncertain tax benefits recognized		0	0
Gain on Sale of IPR&D
Proceeds from sale of IPR&D	$ 4,500,000
Pension Plan | US-based Plan
Employee benefits
Employer contributions		$ 164,600	$ 70,200
Maximum employer matching contribution to 401(k) plan, percent		4.00%	4.00%
Pension Plan | Sweden-based Plan
Employee benefits
Employer contributions		$ 352,000	$ 317,000

Summary of Significant Accoun_8

Summary of Significant Accounting Policies - Recent accounting pronouncements (Details) - USD ($) $ in Millions	Jul. 01, 2018	Jan. 01, 2018
ASU 2016-15
Recently adopted accounting pronouncements
Impact of adoption on financial statements		$ 0
ASU 2018-07 early adoption
Recently adopted accounting pronouncements
Impact of adoption on financial statements	$ 0

Equipment, Net - Summary of equ

Equipment, Net - Summary of equipment (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Cost:
Equipment cost, beginning balance	$ 334,000	$ 143,000
Additions	58,000	190,000
Exchange differences	(2,000)	1,000
Equipment cost, ending balance	390,000	334,000
Less:
Accumulated depreciation, beginning balance	(156,000)	(122,000)
Depreciation for the period	45,000	35,000
Exchange differences	(2,000)	1,000
Accumulated depreciation, ending balance	(203,000)	(156,000)
Property, Plant and Equipment, Net, Total	187,000	178,000
Depreciation expense	$ 47,000	$ 34,000

Accrued Expenses - Summary of A

Accrued Expenses - Summary of Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Payables And Accruals [Abstract]
Accrued bonuses	$ 2,295	$ 1,717
Accrued vacation pay	435	464
Accrued social security pay	214	217
Accrued professional fees	131	470
Accrued development costs	3,257	1,747
Accrued severance	356	152
Accrued other	1,477	1,338
Accrued Liabilities, Current, Total	$ 8,165	$ 6,105

Commitments and Contingencies_2

Commitments and Contingencies (Details)	Jan. 01, 2019SEK (kr)	Jan. 01, 2019USD ($)	Dec. 31, 2018SEK (kr)item	Dec. 31, 2018USD ($)ft²item	Dec. 31, 2017USD ($)
Future minimum commitments under facility operating leases
2,019				$ 333,000
2,020				266,000
2,021				271,000
2,022				91,000
Operating Leases, Future Minimum Payments Due, Total				961,000
Rent expense				$ 403,000	$ 394,000
Operating Lease Corporate Headquarters
Operating Leased Assets [Line Items]
Rentable square feet | ft²				5,116
Term of contract				62 months
Number of options available to extend the lease period | item			1	1
Additional lease term				5 years
Rent abatement period			2 months	2 months
Operating leases quarterly payment				$ 20,997
Annual increase rent payment percentage				2.00%
Operating Lease Office Space In Sweden
Operating Leased Assets [Line Items]
Rentable square feet | ft²				5,100
Term of contract				36 months
Additional lease term				3 years
Operating leases quarterly payment			kr 329,358	$ 36,780
Period of notice for non-renewal of lease			9 months	9 months
Period of notice for termination			6 months	6 months
Operating Lease Office Space In Sweden | Subsequent Event
Operating Leased Assets [Line Items]
Additional lease term	3 years	3 years
Operating leases quarterly payment	kr 329,358	$ 36,780

Commitments and Contingencies -

Commitments and Contingencies - Agreements with CROs (Details) $ in Millions	Dec. 31, 2018USD ($)
Commitments And Contingencies Disclosure [Abstract]
Maximum future payable under agreements with CROs	$ 24.3

Commitments and Contingencies_3

Commitments and Contingencies - Legal contingency (Details) - Ferring International Center S.A. breach complaint € in Millions	Feb. 19, 2019EUR (€)
Gain Contingencies [Line Items]
Contingent fee as percent of net recovery	0.3333%
Minimum
Gain Contingencies [Line Items]
Compensatory damages sought from respondent	€ 37

Commitments and Contingencies_4

Commitments and Contingencies - Other Commitments (Details)	1 Months Ended
	Apr. 30, 2018USD ($)
Commitments And Contingencies Disclosure [Abstract]
One-time launch fee	$ 457,000

Goodwill (Details)

Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill, Beginning Balance	$ 17,260	$ 18,110
Purchasing accounting adjustment		(850)
Goodwill, Ending Balance	$ 17,260	$ 17,260

Net Loss Per Share - Basic EPS

Net Loss Per Share - Basic EPS and Diluted EPS (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Basic and Diluted EPS:
Net loss	$ (46,111)	$ (24,414)
Denominator
Weighted average number of shares outstanding	11,702,785	7,819,302
Basic and Diluted EPS	$ (3.94)	$ (3.12)

Net Loss Per Share - Anti-dilut

Net Loss Per Share - Anti-dilutive Shares Excluded from Computation of Diluted EPS (Details) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Options to purchase common stock and RSUs
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net loss per share	696,710	889,934

Income Taxes - Tax Cuts and Job

Income Taxes - Tax Cuts and Jobs Act (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Effects of the Tax Cuts and Jobs Act
Federal corporate tax rate	21.00%	34.00%

Income Taxes - Components of Lo

Income Taxes - Components of Loss Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
U.S.	$ (13,951)	$ (2,031)
Foreign	(32,140)	(22,171)
Net loss before income taxes	$ (46,091)	$ (24,202)

Income Taxes - Components of In

Income Taxes - Components of Income Tax (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Current tax expense:
Federal		$ (1)
State	$ 21	(12)
Foreign	(1)	225
Total	20	212
Income Tax Expense (Benefit), Total	$ 20	$ 212

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Statutory Income Tax Rate to Consolidated Effective Income Tax Rate (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
U.S. statutory income tax rate	21.00%	34.00%
Stock compensation	(2.00%)	(2.00%)
Permanent differences	(10.00%)
State taxes, net of federal tax effect	2.00%
Change in valuation allowance	(13.00%)	125.00%
Write off of disallowed recognized built in loss		(143.00%)
Change in U.S. tax rate		(4.00%)
Foreign tax rate differences	1.00%	(11.00%)
Other items	1.00%	1.00%
Effective income tax rate	0.00%	0.00%

Income Taxes - Deferred Tax Ass

Income Taxes - Deferred Tax Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Tax loss carryforwards	$ 26,280	$ 21,653
Research and development credits	200	127
Accrued expenses	520	295
Stock compensation	1,400	825
Interest carryforwards	100
Other	50	35
Total gross deferred tax assets	28,550	22,935
Valuation allowance	(28,520)	(22,910)
Total deferred tax assets	30	25
Deferred tax liabilities:
Intangible assets	(30)	25
Total deferred tax liabilities	(30)	25
Net deferred tax assets
Valuation allowance
Expense (benefit) for change in deferred tax asset valuation allowance	$ 5,600	$ (30,200)

Income Taxes - Operating Losses

Income Taxes - Operating Losses and Uncertain tax positions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Net operating loss carryforwards
Tax loss carryforwards	$ 26,280	$ 21,653
Uncertain tax positions
Uncertain tax benefits recognized	0	0
Amount of interest or penalties associated with uncertain tax benefits recognized	0	$ 0
Federal
Net operating loss carryforwards
Net operating loss	1,400
State
Net operating loss carryforwards
Net operating loss	153,900
Non-U.S. Jurisdictions
Net operating loss carryforwards
NOLs that will not expire	75,900
Research and Development Tax Credit Carryforwards | Federal
Tax credit carryforwards
Tax credit carryforwards	73,000,000
Research and Development Tax Credit Carryforwards | State
Tax credit carryforwards
Tax credit carryforwards	$ 160,000,000

Shareholders' Equity (Details)

Shareholders' Equity (Details) - USD ($) $ / shares in Units, $ in Millions	Jan. 29, 2018	May 30, 2017	Feb. 28, 2018	Dec. 31, 2018	Oct. 31, 2017
Preferred Stock
Preferred stock, shares authorized				50,000,000
Preferred stock, shares issued				0
Preferred stock, shares outstanding				0
At-the-Market
Financing
Aggregate offering price					$ 50
Issuance of shares (in shares)			728,862
Proceeds from sale of stock			$ 24.2
Public Offering
Financing
Issuance of shares (in shares)	2,265,500	2,530,000
Price per share of common stock sold	$ 33	$ 20.50
Proceeds from sale of stock	$ 69.9	$ 48.5

Stock-based Compensation - Plan

Stock-based Compensation - Plan Information (Details) - shares	Jun. 08, 2018	Nov. 03, 2016	Sep. 13, 2017
2016 Equity Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized under plan		635,000
Additional number of shares available to be issued if awards outstanding under prior Plans are cancelled, forfeited or expired		249,059
2017 Inducement Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares of common stock available for grant			150,000
2018 Equity Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized under plan	1,200,000
2018 Equity Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Additional number of shares available to be issued if awards outstanding under prior Plans are cancelled, forfeited or expired	1,078,870

Stock-based Compensation - Stoc

Stock-based Compensation - Stock-based compensation expense (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 5,546,000	$ 3,700,000
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	3,735,000	3,406,000
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 1,811,000	294,000
Restatement Adjustment | General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense		$ 788,000

Stock-based Compensation - Summ

Stock-based Compensation - Summary of Outstanding Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Number of Shares
Beginning balance	1,035,361
Granted	608,750
Expirations/forfeitures	(201,825)
Exercises	(72,782)
Ending balance	1,369,504	1,035,361
Weighted-Average Exercise Price Per Share
Beginning balance	$ 17.78
Granted	30.92
Expirations/forfeitures	28.53
Exercises	6.96
Ending balance	$ 22.34	$ 17.78
Exercisable options
Options, exercisable	545,151
Weighted- Average Exercise Price Per Share Exercisable	$ 15.54
Options Outstanding, Weighted Average Remaining Contractual Term (Years)	8 years 22 days	8 years 8 months 16 days
Options Exercisable , Weighted- Average Remaining Contractual Term (Years)	6 years 8 months 16 days
Exercisable options, Aggregate Intrinsic Value	$ 6,596
Aggregate Intrinsic Value
Outstanding options, Aggregate Intrinsic Value Beginning	11,896
Outstanding options, Aggregate Intrinsic Value Ending	$ 8,421	$ 11,896
Vested and Expected to Vest
Number of Shares	1,350,082
Weighted- Average Exercise Price Per Share	$ 22.65
Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1	6 years 8 months 16 days
Weighted- Average Remaining Contractual Term (Years)	8 years 26 days
Aggregate Intrinsic Value	$ 7,964

Stock-based Compensation - Addi

Stock-based Compensation - Additional information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options, exercisable	545,151
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total unrecognized compensation expense related to unvested options | $	$ 14.1
Weighted average vesting period for unvested options	2 years 7 months 6 days
Performance Based Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options, non vested	19,422

Stock-based Compensation - Fair

Stock-based Compensation - Fair value assumptions of stock option awards (Details) - Employee Stock Option - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Fair value assumptions
Dividend rate	0.00%	0.00%
Minimum
Fair value assumptions
Price per share of common stock	$ 26.27	$ 17.05
Expected term (in years)	5 years 6 months	5 years 2 months 12 days
Risk-free interest rate	2.60%	1.90%
Expected volatility	84.40%	69.50%
Maximum
Fair value assumptions
Price per share of common stock	$ 33.61	$ 26.12
Expected term (in years)	6 years	6 years 10 months 24 days
Risk-free interest rate	3.10%	2.30%
Expected volatility	89.90%	78.40%

Stock-based Compensation - Rest

Stock-based Compensation - Restricted Stock Units (Details) - RSUs	12 Months Ended
	Dec. 31, 2018$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of share of common stock represented by each RSU	1
Vesting percentage on first anniversary	25.00%
Shares
RSUs granted	5,000
Non-vested and outstanding balance, end of period	5,000
Weighted Average Grant-Date Fair Value
RSUs granted | $ / shares	$ 27.98
Non-vested and outstanding balance, end of period | $ / shares	$ 27.98

Stock-based Compensation - Empl

Stock-based Compensation - Employee Stock Purchase Plan (Details)	Jun. 30, 2018shares
2018 Employee Stock Purchase Plan
Employee Stock Purchase Plan
Shares available to be issued under the ESPP	300,000

Long-term Debt - Loan Facility

Long-term Debt - Loan Facility (Details) - USD ($)	1 Months Ended	12 Months Ended
	May 31, 2017	Dec. 31, 2017
Kreos Warrants
Debt Instrument [Line Items]
Common stock issued in cashless exercise of warrants (in shares)	29,831
Loan Facility
Debt Instrument [Line Items]
Interest paid on loan facility		$ 178,000
Debt discount remaining		0
Discount accretion included in interest expense		$ 161,000