Albireo Pharma (ALBO) 10-K 1 Mar 22 2021 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Feb. 22, 2022	Jun. 30, 2021
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Document Transition Report	false
Entity File Number	001-33451
Entity Registrant Name	Albireo Pharma, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	90-0136863
Entity Address, Address Line One	53 State Street, 19th Floor
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02109
City Area Code	857
Local Phone Number	254-5555
Title of 12(b) Security	Common Stock
Trading Symbol	ALBO
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Public Float			$ 672.7
Entity Common Stock, Shares Outstanding		19,361,898
Auditor Firm ID	42
Auditor Name	Ernst & Young LLP
Auditor Location	Boston, Massachusetts
Entity Central Index Key	0001322505
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Amendment Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 248,107	$ 251,272
Accounts receivable, net	3,272	0
Inventory	194
Prepaid expenses	5,261	7,564
Other current assets	12,096	3,029
Total current assets	268,930	261,865
Property and equipment, net	668	478
Goodwill	17,260	17,260
Other assets	15,193	6,004
Total assets	302,051	285,607
Current liabilities:
Accounts payable	6,516	5,283
Accrued expenses	35,951	19,051
Other current liabilities	2,880	948
Total current liabilities	45,347	25,282
Liability related to sale of future royalties	60,132	65,894
Note payable, net of discount	10,004	9,621
Other long-term liabilities	10,960	3,579
Total liabilities	126,443	104,376
Stockholders' Equity:
Preferred stock, $0.01 par value per share - 50,000,000 shares authorized at December 31, 2021 and December 31, 2020; 0 and 0 shares issued and outstanding at December 31, 2021 and December 31, 2020, respectively
Common stock, $0.01 par value per share - 60,000,000 and 30,000,000 shares authorized at December 31, 2021 and December 31, 2020, respectively; 19,304,312 and 19,296,552 shares issued and outstanding at December 31, 2021, respectively, and 19,107,040 shares issued and outstanding at December 31, 2020	193	191
Additional paid-in capital	475,390	456,472
Accumulated other comprehensive income (loss)	1,105	(8,612)
Accumulated deficit	(300,850)	(266,820)
Treasury stock at cost, 7,760 shares and 0 shares at December 31 2021 and December 31, 2020, respectively	(230)
Total stockholders' equity	175,608	181,231
Total liabilities and stockholders' equity	$ 302,051	$ 285,607

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Consolidated Balance Sheets
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	60,000,000	30,000,000
Common stock, shares issued	19,304,312	19,107,040
Common stock, shares outstanding	19,296,552	19,107,040
Treasury stock at cost, shares	7,760	0

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Revenue:
Revenue	$ 40,579	$ 8,308
Cost of product revenue	$ 1,356
Cost, Product and Service	Product
Gross profit	$ 39,223	8,308
Operating expenses:
Research and development	82,522	76,777
Selling, general and administrative	69,569	42,448
Other operating expense (income) net	10,617	(14,646)
Total operating expenses	162,708	104,579
Operating loss	(123,485)	(96,271)
Other income (loss):
Gain from sale of priority review voucher, net of transaction costs	103,387
Interest expense, net	(13,932)	(11,362)
Net loss	$ (34,030)	$ (107,633)
Net loss per common share
Basic (in dollars per share)	$ (1.77)	$ (6.73)
Diluted (in dollars per share)	$ (1.77)	$ (6.73)
Weighted-average common shares used to compute basic and diluted net loss per common share
Basic (in shares)	19,220,846	15,983,058
Diluted (in shares)	19,220,846	15,983,058
Product
Revenue:
Revenue	$ 6,993	$ 0
Royalty
Revenue:
Revenue	18,586	$ 8,308
License
Revenue:
Revenue	$ 15,000

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Consolidated Statements of Comprehensive Income (Loss)
Net loss	$ (34,030)	$ (107,633)
Other comprehensive income (loss):
Foreign currency translation adjustment	9,717	(15,064)
Total other comprehensive income (loss)	9,717	(15,064)
Total comprehensive loss	$ (24,313)	$ (122,697)

Consolidated Statements of Shar

Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income	Accumulated Deficit	Treasury Stock At Cost	Total
Balance at beginning of period at Dec. 31, 2019	$ 127	$ 245,769	$ 6,452	$ (159,187)		$ 93,161
Balance (in shares) at Dec. 31, 2019	12,749,443
Increase (Decrease) in Stockholders' Equity
Share based compensation expense		14,615				14,615
Exercise of options and vesting of RSUs and ESPP	$ 2	2,772				2,774
Exercise of options and vesting of RSUs and ESPP (in shares)	166,847
Issuance of warrants		113				113
Issuance of common stock, net of costs	$ 62	193,203				193,265
Issuance of common stock (in shares)	6,190,750
Other comprehensive income (loss)			(15,064)			(15,064)
Net loss				(107,633)		(107,633)
Balance at end of period at Dec. 31, 2020	$ 191	456,472	(8,612)	(266,820)		181,231
Balance (in shares) at Dec. 31, 2020	19,107,040
Increase (Decrease) in Stockholders' Equity
Share based compensation expense		15,931				15,931
Exercise of options and vesting of RSUs and ESPP	$ 2	2,746				2,748
Exercise of options and vesting of RSUs and ESPP (in shares)	189,764
Issuance of common stock, net of costs		241				241
Issuance of common stock (in shares)	7,508
Other comprehensive income (loss)			9,717			9,717
Purchases of treasury stock, at cost					$ (230)	(230)
Purchases of treasury stock, at cost (in shares)					(7,760)
Net loss				(34,030)		(34,030)
Balance at end of period at Dec. 31, 2021	$ 193	$ 475,390	$ 1,105	$ (300,850)	$ (230)	$ 175,608
Balance (in shares) at Dec. 31, 2021	19,304,312				(7,760)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net loss	$ (34,030)	$ (107,633)
Adjustments to reconcile net loss to net cash used in operating activities:
Gain from sale of priority review voucher, net of transaction costs	(103,387)
Accretion of liability related to sale of future royalties	12,528	10,778
Accretion of debt discount and amortization of issuance costs	383	248
Depreciation and amortization	274	192
Share based compensation expense	15,931	14,615
Foreign currency adjustments	10,423	(14,573)
Changes in operating assets and liabilities:
Accounts receivable, net	(3,291)
Inventory	(194)
Prepaid expenses and other current assets	(6,615)	(508)
Other assets	(74)	575
Accounts payable	1,336	275
Accrued expenses	17,326	(4,774)
Other current and long-term liabilities	(18,169)	(224)
Net cash used in operating activities	(107,559)	(101,029)
Cash flows from investing activities:
Purchase of property and equipment	(465)	(78)
Proceeds from sale of priority review voucher, net of transaction costs	103,387
Net cash provided by (used in) investing activities	102,922	(78)
Cash flows from financing activities:
Proceeds from issuance of common stock, net of issuance costs	241	193,265
Proceeds from royalty agreement, net of issuance costs		14,750
Proceeds from issuance of debt, net of issuance costs		9,487
Proceeds from exercise of options	2,748	2,774
Payments related to repurchases of common stock	(230)
Net cash provided by financing activities	2,759	220,276
Effect of exchange rate changes on cash and cash equivalents	(1,287)	260
Net (decrease) increase in cash and cash equivalents	(3,165)	119,429
Cash and cash equivalents - beginning of period	251,272	131,843
Cash and cash equivalents - end of period	248,107	251,272
Supplemental disclosures of cash and non-cash activities
Warrants issued with long-term debt		$ 113
Right of use assets obtained in exchange for operating lease obligations	$ 8,591

Summary of significant accounti

Summary of significant accounting policies and basis of presentation	12 Months Ended
	Dec. 31, 2021
Summary of significant accounting policies and basis of presentation
Summary of significant accounting policies and basis of presentation	1. Summary of significant accounting policies and basis of presentation Organization Albireo Pharma, Inc. (the Company), is a commercial-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 product pipeline includes Bylvay, which is approved in the United States and Europe, elobixibat, which is approved in Japan for the treatment of chronic constipation, A3907 our Phase 1 lead candidate for the treatment of adult liver diseases, and A2342 our lead preclinical candidate for the treatment of adult viral and liver diseases. Bylvay was approved by the U.S. Food and Drug Administration on July 20, 2021 for the treatment of pruritis in patients with progressive familial intrahepatic cholestasis (PFIC) ages 3 months or older, and authorized by the European Medicines Agency on July 16, 2021 for the treatment of PFIC in patients 6 months or older. Bylvay was also granted marketing authorization by the UK Medicines and Healthcare Products Regulatory Agency (MHRA) in September 2021 for the treatment of PFIC in patients 6 months or older. Bylvay is also in Phase 3 development for the treatment of biliary atresia and Alagille syndrome (ALGS), each a rare, life-threatening disorder affecting young children. ​ Since its inception, the Company has devoted substantially all of its resources to its research and development efforts, including activities to develop its product candidates, commercialize Bylvay in PFIC and provide general and administrative support for these operations. ​ 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). Principles of consolidation The accompanying Consolidated Financial Statements include the accounts of the Company including 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 subsidiary 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 in 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’s subsidiaries’ 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, 2021 and 2020; 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, realizability of 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 for elobixibat 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 credit risk related to product sales is limited to customers to whom the Company makes significant sales. The Company has no allowance for doubtful accounts. An allowance for doubtful accounts is determined based on the company’s assessment of the credit worthiness and financial condition of its customers, aging of receivables, as well as the general economic environment. Any allowance would reduce the net receivables to the amount that is expected to be collected. For the year ended December 31, 2021 there were 3 customers or collaboration partners who individually accounted for approximately 44%, 35% and 10% of the Company’s gross revenue balance. For the year ended December 31, 2021, there were 3 customers who individually accounted for 43%, 24% and 12% of the Company’s gross accounts receivable balance. The Company believes that credit risks associated with these contracts are not significant due to the customers’ financial strengths. For the year ended December 31, 2020, all revenue and receivables relate to one licensee Property and equipment, net Property and equipment, including leasehold improvements, are recorded at cost and depreciated when placed into service using the straight-line method, based on their estimated useful lives as follows: ​ ​ ​ ​ ​ ​ Estimated Useful Life Asset Classification (in years) IT Equipment ​ 3 5 Vehicles ​ 5 Leasehold improvements ​ Lesser of useful life or lease term Furniture and fixtures ​ 5 7 ​ Property and equipment purchased for less than $10,000 are expensed immediately. Costs for repairs and maintenance are expensed as incurred. Gains and losses on disposals of equipment are determined by comparing the proceeds with the carrying amount and are recognized within Other operating expense (income), 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, which generally is determined from estimated discounted future net cash flows (assets held for use) or net realizable value (assets held for sale). There were no impairments recorded for the years ended December 31, 2021 and 2020. Operating Leases Operating lease assets and liabilities are recognized at the lease commencement date based on the present value of the lease payments over the lease term using the discount rate implicit in the lease. The present value of future lease payments are discounted using the interest rate implicit in lease contracts if that rate is readily determinable; otherwise the Company utilizes its incremental borrowing rate (‘‘IBR’’), which reflects the fixed rate at which the Company could borrow on a collateralized basis over a similar term, the amount of the lease payments in a similar economic environment. Historically, the rate implicit in the leases has not been readily determinable and the appropriate incremental borrowing rate has been utilized. To estimate the appropriate incremental borrowing rate, a credit rating applicable to the Company is estimated using a synthetic credit rating analysis since the Company does not currently have a rating agency-based credit rating. 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 and 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 recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the Company expects to receive in exchange for those goods or services in accordance with ASC 606 Revenue from Contracts with Customers Product Revenue, Net The Company recognizes revenue on sales of Bylvay when a customer obtains control of the product, which occurs at a point in time and upon delivery. The Company sells Bylvay to a limited number of specialty pharmacies and a specialty distributor which dispense the product directly to patients. The specialty pharmacies and specialty distributor are referred to as the Company’s customers. The Company also sells Bylvay to its customers in the European Union, which includes a limited number of pharmacies. The Company provides the right of return to its customers for unopened product for a limited time before and after its expiration date. We currently estimate product returns using available industry data as well as the Company’s visibility into the inventory remaining in the distribution channel. The Company has written contracts with each of its customers that have a single performance obligation to deliver products upon receipt of a customer order and these obligations are satisfied when delivery occurs and the customer receives Bylvay. The Company evaluates creditworthiness of each of its customers to determine whether collection is reasonably assured. The wholesale acquisition cost that the Company charges its customers for Bylvay is adjusted to arrive at our estimated net product revenues by deducting components of variable consideration which include (i) estimated government rebates and discounts related to Medicaid and other government programs, (ii) estimated costs of incentives offered to certain indirect customers including patients, (iii) trade allowances, such as invoice discounts for prompt payment and customer fees, and (iv) allowance for sales returns. Product revenue, net was ​ ​ ​ Rebates and Discounts The Company contracts with the Centers for Medicare & Medicaid Services and other government agencies in the U.S. to make Bylvay available to eligible patients. As a result, the Company estimates any rebates and discounts, including chargebacks related to 340b, and deducts these estimated amounts from its gross product revenues at the time the revenues are recognized. The Company’s estimates of rebates and discounts are based on the government mandated discounts, which are statutorily-defined and applicable to these government funded programs and assumptions developed using historical experience with actual payments and redemptions. The Company recorded $0.7 million and $0.0 million in such estimates as of December 31, 2021 and December 31, 2020, respectively, in accounts receivable, net and other current liabilities on the consolidated balance sheets. The Company contracts with national authorities in Europe to make Bylvay available to eligible patients. In jurisdictions in which final pricing is subject to ongoing negotiations with the government, the Company estimates the rebate expected to be due and deducts these estimated amounts from its gross product revenues at the time the revenues are recognized. The Company’s estimates of such liabilities are based on current invoice pricing and total prior units sold and assumptions developed using benchmarks of Bylvay pricing approved in other relevant European jurisdictions. The Company recorded $0.2 million and $0.0 million in such estimates as of December 31, 2021 and December 31, 2020, respectively, in other current liabilities on the consolidated balance sheets. Other Incentives Other incentives that the Company offers to indirect customers include co-pay assistance cards provided by the Company for patients who reside in states that permit co-pay assistance programs. The Company’s co-pay assistance program is intended to reduce each participating patient’s portion of the financial responsibility for Bylvay’s purchase price to a specified dollar amount. The Company estimates the amount of co-pay assistance provided to eligible patients based on the terms of the program when product is dispensed by the specialty pharmacies to the patients. These estimates are based on redemption information provided by third-party claims processing organizations. The Company funds this incentive program through upfront payments which included a $0.1 million payment in the year ended December 31, 2021. The Company recorded less than $0.1 million and $0.0 million in such estimates as of December 31, 2021 and December 31, 2020, respectively, in prepaid expenses and other current assets on the consolidated balance sheets. Trade Allowances The Company provides invoice discounts on Bylvay sales to its customers for prompt payment and records these discounts as a reduction to gross product revenues. These discounts are based on contractual terms. The Company also pays fees to its distributors for their services as well as data that they provide to the Company. Prompt payment allowances are recorded in accounts receivable, net on the consolidated balance sheets and were less than $0.1 million for the year ended December 31, 2021. The other distributor fees are recorded as other current liabilities on the consolidated balance sheets and were $0.1 million for the year ended December 31, 2021. There were no trade allowances recorded for the year ended December 31, 2020. Trade Receivables, net Accounts receivable, net related to product sales, which are recorded in accounts receivable, net on the consolidated balance sheets, were approximately $3.3 million and $0 million as of December 31, 2021 and December 31, 2020, respectively. As of December 31, 2021 and December 31, 2020, we had no allowance for doubtful accounts. An allowance for doubtful accounts is determined based on the Company’s assessment of the credit worthiness and financial condition of its customers, aging of receivables, as well as the general economic environment. Any allowance would reduce the net receivables to the amount that is expected to be collected. Payment terms for U.S. customers are typically 31 ​ Contract Revenue and Milestone Payments At the inception of each arrangement that includes development milestone payments or upfront payment, the Company evaluates whether the milestones are considered probable of being achieved and estimates the amount to be included in the transaction price, which includes any upfront payments, 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. Once the estimated transaction price is established, the associated consideration is allocated to the performance obligations that have been identified in the respective agreement. 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 has completed all of its performance obligations under the Agreement. As of December 31, 2021, the Company is eligible to receive an additional regulatory-based milestone payment under the Agreement of $4.9 million 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 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. Monetization of Future Royalties In December 2017, the Company entered into a royalty interest acquisition agreement (RIAA) with HealthCare Royalty Partners III, L.P. (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. In January 2018, the Company received $44.5 million from HCR, net of certain transaction expenses, under the RIAA. On June 8, 2020, the parties entered into an amendment to the RIAA pursuant to which HCR agreed to pay the Company an additional $14.8 million, net of certain transaction expenses, in exchange for the elimination of the (i) $78.8 million cap amount on HCR’s rights to receive royalties on sales in Japan and sales milestones for elobixibat in certain other territories that may become payable by EA Pharma and (ii) the $15.0 million payable to the Company if a specified sales milestone is achieved for elobixibat in Japan. 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 and milestones as revenue. Upon receipt of the payments from HCR the Company recorded net cash totaling $59.3 million as a liability related to sale of future royalties (royalty obligation). The royalty obligation will be amortized using the effective interest rate method. The following table shows the activity within the liability account for the year ended December 31, 2021: ​ ​ ​ ​ ​ ​ ​ December 31, 2021 ​ (in thousands) Liability related to sale of future royalties—beginning balance $ 68,594 Accretion of interest expense on liability related to royalty monetization ​ ​ 12,528 Repayment of the liability ​ ​ (9,455) Liability related to sale of future royalties—ending balance $ 71,667 Less current portion classified within accrued expenses ​ ​ (11,535) Long-term liability related to sale of future royalties $ 60,132 ​ The Company records estimated royalties due for the current period in accrued other expenses until the payment is received from EA Pharma at which time the Company then remits payment to HCR. In order to determine the accretion of the royalty obligation, the Company is required to estimate the total amount of future royalty payments to be received and submitted to HCR. The sum of these amounts less the $59.3 million proceeds the Company received will be recorded as interest expense over the life of the royalty obligation. At December 31, 2021, the Company’s estimate of its total interest expense resulted in an annual effective interest rate of approximately 18.1%. 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. Inventory The Company commenced capitalizing inventory for Bylvay upon FDA approval on July 20, 2021. All commercial manufacturing expenses were expensed as research and development expenses prior to FDA approval. Manufacturing of the Company’s active pharmaceutical ingredient (API) and drug product occurred prior to FDA approval. As a result, manufacturing costs, which totaled approximately $1.6 million, were not capitalized, and instead were expensed as research and development expenses from 2020 until FDA approval in July 2021. ​ Stock-based compensation The Company accounts for stock-based compensation awards in accordance with FASB ASC Topic 718, Compensation—Stock Compensation 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, 2021 and December 31, 2020, 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. Employee benefits Pension obligations The Company has a defined contribution pension plan 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 paid $0.7 million and $0.7 million to the plans for the years ended December 31, 2021 and 2020, 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 $0.7 million and $0.5 million to the plan for the years ended December 31, 2021 and 2020, 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, 2021 and 2020. 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 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, 2021 and 2020, 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 and 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. Goodwill Goodwill is the excess of the purchase price in a business combination over the fair value of identifiable net assets acquired. Goodwill has an indefinite life and is subject to annual testing for impairment. Goodwill is assessed at least annually, but also whenever events or changes in circumstances indicate the carrying value 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 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. The Company uses its market capitalization as a proxy for its fair value. During the fourth quarter of 2021 and 2020, we completed our annual impairment assessment and concluded

Fair value of financial instrum

Fair value of financial instruments	12 Months Ended
	Dec. 31, 2021
Fair value of financial instruments
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 Level 2—Observable inputs such as quoted prices for similar Level 3—Unobservable inputs that reflect the reporting entity’s estimate of assumptions that market participants would use in pricing the asset or liability. The following tables represent information about the Company’s financial assets that are measured at fair value on a recurring basis (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 ​ ​ Level 1 ​ Level 2 ​ Level 3 Cash Equivalents: ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ 243,180 ​ $ — ​ $ — Total ​ $ 243,180 ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ Level 1 ​ Level 2 ​ Level 3 Cash Equivalents: ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ 242,854 ​ $ — ​ $ — Total ​ $ 242,854 ​ $ — ​ $ — ​ ​ The Company’s financial instruments consist mainly of cash equivalents, prepaid expenses and other current assets, accounts payable, accrued expenses, other current liabilities, and note payable. The carrying amounts of cash equivalents, prepaid expenses and other current liabilities, accounts payable, accrued expenses, and other current liabilities approximate their estimated fair value due to their short-term maturities. At December 31, 2021, the Company believes the carrying value of the Loan and Security Agreement with Hercules Capital, Inc., approximates the fair value of the note payable, considering that it bears interest that is similar to prevailing market rates.

Property and equipment, net

Property and equipment, net	12 Months Ended
	Dec. 31, 2021
Property and equipment, net
Property and equipment, net	3. Property and equipment, net Property and equipment, net consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, ​ 2021 2020 IT equipment ​ $ 773 $ 318 Leasehold improvements ​ 58 ​ 58 Furniture and fixtures ​ 450 ​ 453 Total property and equipment, gross ​ 1,281 ​ 829 Less: Accumulated depreciation ​ (613) ​ (351) Total property and equipment, net ​ $ 668 $ 478 ​ Depreciation expense for the years ended December 31, 2021 and 2020 was $0.3 million and $0.2 million, respectively.

Accrued expenses

Accrued expenses	12 Months Ended
	Dec. 31, 2021
Accrued expenses
Accrued expenses	4. Accrued expenses Accrued expenses consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, ​ 2021 2020 Accrued payroll and benefits ​ $ 10,310 $ 8,492 Accrued professional fees ​ 1,024 ​ 649 Accrued development costs ​ 10,442 ​ 5,968 Accrued liability related to monetization of future royalties ​ 11,535 ​ 2,700 Accrued other ​ 2,640 ​ 1,242 Total accrued expenses ​ $ 35,951 $ 19,051 ​

Commitments and contingencies

Commitments and contingencies	12 Months Ended
	Dec. 31, 2021
Commitments and contingencies
Commitments and contingencies	5. Commitments and contingencies Operating lease commitments The Company’s portfolio of commercial real estate leases consists of office space for its corporate headquarters in Boston, Massachusetts, additional office space in Boston, Massachusetts , ​ The Company subleases a portion of its 10 Post Office space to a third party for which it receives rental income to manage occupancy costs. This sublease is classified as operating and is further described below. ​ 10 Post Office ​ On February 7, 2017, the Company entered into an agreement with Shigo 10 Power Owner LLC (as amended, the “10 Post Office Lease”) to lease 5,116 square feet of office space on the 5th floor of ​ On March 28, 2019, the Company entered into an amendment to the 10 Post Office Lease to (i) replace the Company’s prior office space with 14,734 square feet of new office space that is being leased from the same landlord and (ii) extend the term of the lease through October 31, 2026. The new leased space contains monthly lease payments subject to annual escalations of $1.00 per square foot for the remaining term of the lease with the Company obligated to make approximately $12.2 million of aggregate lease payments over the term of the lease, or approximately $1.7 million annually. ​ On May 4, 2020, the Company entered into a second amendment to the 10 Post Office Lease to lease an additional 3,490 square feet of office space on the 10th floor of 10 Post Office Square, Boston, MA from NS Boston III PO Owner LLC from July 1, 2020 through June 30, 2021. The Company entered into additional amendments at 10 Post Office Lease in 2020 and 2021 to extend the term of the 10 Post Office Lease further. The 10 Post Office Lease is classified as a short-term lease and is currently set to expire on March 31, 2022. ​ On December 6, 2021, the Company entered into an agreement (the “10 Post Office Sublease”) to sublease 14,734 square feet of office space located at 10 Post Office Square, Boston, MA ​ Goteborg ​ The Company’s lease in Göteborg, Sweden includes the rental of office space. This lease includes annual rent escalations based on the changes in the Swedish Consumer Price Index. ​ 53 State Street ​ On December 7, 2021, the Company entered into an agreement (the “53 State Street Lease”) to lease 26,962 square feet on the 19th floor of 53 State Street, Boston, MA from the Institute for Healthcare Improvement from December 15, 2021 through January 31, 2030. ​ As of December 31, 2021 the net balance of ROU assets totaled $12.0 million and was classified within other non-current assets ​ Pursuant to the Company’s non-cancelable lease agreements in effect at December 31, 2021, the following table summarizes the Company’s maturities of lease liabilities as of December 31, 2021: ​ ​ ​ ​ ​ ​ ​ Total Minimum Lease Payments ​ (in thousands) 2022 ​ ​ 1,772 2023 ​ ​ 2,421 2024 ​ ​ 2,466 2025 ​ ​ 2,511 2026 and beyond ​ ​ 7,507 Total minimum lease payments ​ $ 16,677 Less imputed interest ​ ​ (4,463) Total lease liability ​ $ 12,214 ​ ​ ​ ​ Reported as: ​ ​ ​ Other current liabilities ​ $ (1,396) Other long-term liabilities ​ ​ (10,818) Total lease liabilities ​ $ (12,214) ​ Agreements with CROs As of December 31, 2021, 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, the Company is contractually obligated to make future payments of up to $11.8 million upon the completion of contracted work.

Inventory

Inventory	12 Months Ended
	Dec. 31, 2021
Inventory
Inventory	6. Inventory Inventory consists of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 December 31, 2020 Raw materials ​ $ — ​ $ — Work-in-process ​ ​ — ​ ​ — Finished goods ​ ​ 194 ​ ​ — Total inventory ​ $ 194 ​ $ — ​ There were no write downs for excess and obsolete inventory during the years ended December 31, 2021 or 2020 based on the finish goods inventory shelf life of 24 months , and an analysis over the future demand for Bylvay relative to the remaining shelf life of inventory as of December 31, 2021.

Note Payable

Note Payable	12 Months Ended
	Dec. 31, 2021
Note Payable
Note Payable	7. Note Payable 2020 Loan and Security Agreement On June 8, 2020, the Company entered into a Loan and Security Agreement (the Loan and Security Agreement) with the several banks and other financial institutions or entities from time to time parties to the Loan and Security Agreement, as lenders (collectively, referred to as the “Lender”), and Hercules Capital, Inc., in its capacity as administrative agent and collateral agent for itself and Lender (in such capacity, the “Agent” or “Hercules”) which provides for term loans of up to an aggregate principal amount of $80.0 million (the “Term Loans”) to the Company. The Loan Agreement provides for (i) an initial term loan advance of $10.0 million, which closed on June 8, 2020, (ii) subject to the achievement of certain initial performance milestones (“Performance Milestone I”), a right of the Company to request that the Lender make additional term loan advances to the Company in an aggregate principal amount of up to $20.0 million from January 1, 2021 through December 15, 2021 in minimum increments of $10.0 million, and (iii) subject to the Lender’s investment committee’s sole discretion, a right of the Company to request that the Lender make additional term loan advances in an aggregate principal amount of up to $45.0 million through March 31, 2022 in minimum increments of $5.0 million. The Company is required to pay an end of term fee (“End of Term Charge”) equal to 6.95% of the aggregate principal amount of the Term Loans advances upon repayment. The Term Loans mature on January 1, 2024, which is extendable to June 1, 2024 upon achievement of Performance Milestone I (the “Maturity Date”). The Term Loan bears interest at an annual rate equal to greater of 9.15% and 9.15% plus the prime rate of interest minus 3.25%. Borrowings under the Loan and Security Agreement were repayable in monthly interest-only payments through January 1, 2022 and extendable to (i) July 1, 2022 upon achievement of Performance Milestone I and (ii) July 1, 2023 upon achievement of certain additional performance milestones. After the interest-only payment period, borrowings under the Loan and Security Agreement are repayable in equal monthly payments of principal and accrued interest until the Maturity Date. At the Company’s option, the Company may elect to prepay all, but not less than all, of the outstanding term loan by paying the entire principal balance and all accrued and unpaid interest thereon plus a prepayment charge equal to the following percentage of the principal amount being prepaid: 2.0% of the principal amount outstanding if the prepayment occurs after the first nine months following the Closing Date, but on or prior to 24 months following the Closing Date, and 1.0% of the principal amount outstanding at any time thereafter but prior to the Maturity Date. In connection with the Loan Agreement, the Company granted Agent a security interest The Loan Agreement also contains certain events of default, representations, warranties and non-financial covenants of the Company. The debt discount and issuance costs are being accreted to the principal amount of debt and being amortized from the date of issuance through the Maturity Date to interest expense using the effective-interest rate method. The effective interest rate of the outstanding debt under the Loan Agreement is approximately 13.0%. As of December 31, 2021 the carrying value of the note payable consists of the following: ​ ​ ​ ​ ​ ​ ​ December 31, 2021 ​ (in thousands) Note payable, including End of Term Charge ​ ​ 10,695 Debt discount, net of accretion ​ ​ (691) Note payable net of discount, long-term ​ $ 10,004 ​ During the year ended December 31, 2021, the Company recognized $1.3 million, of interest expense related to the Loan Agreement. The Company recognized $0.8 million of interest expense related to the Loan Agreement for the year ended December 31, 2020. Through December 31, 2021 and December 31, 2020, the Company borrowed $10.0 million and $10.0 million, respectively, under the Loan Agreement and incurred expenses of $0.4 million and $0.2 million, respectively, of debt discount and issuance costs inclusive of facility fees, legal fees, End of Term Charge and fair value of the warrant. ​ Estimated future principal payments due under the Loan Agreement, including the contractual End of Term Charge are as follows as of December 31, 2021: ​ ​ ​ ​ ​ ​ ​ Note Principal Payments ​ ​ (in thousands) 2022 ​ $ — 2023 ​ ​ 5,254 2024 ​ ​ 5,441 ​ As of December 31, 2021, based on Level 3 inputs and the borrowing rates available to the Company for loans with similar terms and consideration of the Company’s credit risk, the carrying value of the Company’s variable interest rate debt, excluding unamortized debt issuance costs, approximates fair value. Warrants ​ Under the Loan and Security Agreement, the Company agreed to issue to Hercules warrants (the “Warrants”) to purchase a number of shares of the Company’s common stock, par value $0.01 per share (the “Common Stock”) equal to 1% of the aggregate amount of the Term Loans that are funded, as such amounts are funded. On the Closing Date, the Company issued a Warrant for 5,311 shares of Common Stock. The Warrants will be exercisable for a period of seven years from the date of the issuance of each Warrant at a per-share exercise price equal to $18.83, subject to certain adjustments as specified in the Warrants. In addition, the Company has granted to the holders of the Warrants certain registration rights. Specifically, the Company has agreed to use its commercially reasonable efforts to (i) file registration statements with the U.S. Securities and Exchange Commission within 60 days following the date of the issuance of each Warrant for purposes of registering the shares of Common Stock issuable upon exercise of the Warrants for resale by Hercules, and (ii) cause the registration statement to be declared effective as soon as practicable after filing, and in any event no later than 180 days after the date of the issuance of each Warrant. The Company accounted for the Warrants as equity instruments since they were indexed to the Company’s common stock and met the criteria for classification in stockholders’ equity. The relative fair value of the Warrants related to the first tranche funding was approximately $0.1 million, and was treated as a discount to the Term Loans. This amount is being amortized to interest expense using the effective interest method over the life of the Term Loans. The Company estimated the fair value of the Warrants using the Black-Scholes option-pricing model.

Net loss per share

Net loss per share	12 Months Ended
	Dec. 31, 2021
Net loss per share
Net loss per share	8. Net loss per share The following table sets forth the computation of Basic loss per share and Diluted loss per share (in thousands, except for share and per share data): ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ 2021 2020 Basic and Diluted net loss per share: ​ ​ ​ ​ ​ ​ Numerator ​ ​ ​ ​ ​ ​ Net loss ​ $ (34,030) $ (107,633) Denominator ​ ​ ​ ​ Weighted average number of shares outstanding ​ 19,220,846 ​ ​ 15,983,058 Basic and Diluted loss per share ​ $ (1.77) $ (6.73) ​ The following outstanding common stock equivalents were excluded from the computation of Diluted loss per share for the periods presented because including them would have been anti-dilutive: ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ 2021 2020 ​ Options to purchase common stock, RSUs and warrants ​ 3,208,398 ​ 2,413,037 ​ ​

Income taxes

Income taxes	12 Months Ended
	Dec. 31, 2021
Income taxes
Income taxes	9. Income taxes The Company has had an overall net operating loss position since its inception. There was no current or deferred tax provision for the years ended December 31, 2021 and 2020. For the years ended December 31, 2021 and 2020, the components of loss before income taxes were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, ​ 2021 2020 U.S. ​ $ (18,603) $ (86,041) Foreign ​ (15,427) (21,592) Total ​ $ (34,030) $ (107,633) ​ A reconciliation of the U.S. statutory income tax rate to the consolidated effective income tax rate was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ ​ December 31, ​ ​ 2021 2020 ​ U.S. statutory income tax rate ​ 21 % 21 % Stock compensation ​ (3) ​ — ​ State taxes, net of federal tax effect ​ 1 ​ 5 ​ Change in valuation allowance ​ (19) ​ (26) ​ Change in deferred tax rate ​ (1) ​ — ​ Forfeited losses and tax attributes ​ — ​ — ​ Other items ​ 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, ​ 2021 2020 Deferred tax assets: ​ ​ ​ ​ ​ ​ Tax loss carryforwards ​ $ 59,230 $ 59,790 Research and development credits ​ 130 ​ 130 Accrued expenses ​ 1,770 ​ 1,870 Stock compensation ​ 6,790 ​ 4,750 Interest carryforwards ​ ​ 6,670 ​ ​ 4,420 Other ​ 3,150 ​ 1,220 Total gross deferred tax assets ​ 77,740 ​ 72,180 Valuation allowance ​ (74,690) ​ (71,040) Total deferred tax assets ​ $ 3,050 ​ $ 1,140 Deferred tax liabilities: ​ ​ ​ ​ Intangible assets ​ $ (20) $ (20) Right of use asset ​ (3,030) ​ (1,120) Total deferred tax liabilities ​ (3,050) ​ (1,140) 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 recorded a valuation allowance of $74.7 million and $71.0 million at December 31, 2021 and 2020, respectively. The change in valuation allowance for the years ended December 31, 2021 and 2020, were $3.7 million and $31.1 million, respectively. As of December 31, 2021, deferred tax assets related to net operating loss (NOL) carryforwards were $59.2 million, which may be used subject to certain limitations to offset future taxable income, if any. The NOL includes approximately $1.5 million for U.S. federal tax purposes that are subject to expire in 2036 and approximately $98.8 million of federal net operating losses which have no expiration date and can be carried forward indefinitely. The Company has state NOLs of approximately $246.3 million which may be available to offset future income tax liabilities and that expire at various dates through 2041. Additional NOLs of approximately $112.5 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. 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 Section 382 of the Internal Revenue Code of 1986 (the Code), results from transactions increasing the ownership of certain stockholders 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. 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 more likely than not that a tax benefit will be sustained, no tax benefit is recognized. As of December 31, 2021 and 2020, 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 Great Britain and Sweden. The Company’s tax returns may be examined for certain tax jurisdictions back to December 31, 2018. The Company is subject to a territorial tax system under the Act, in which the Company is required to provide for tax on Global Intangible Low-Taxed Income (GILTI) earned by certain foreign subsidiaries. The Company has adopted an accounting policy to provide for the tax expense related to GILTI in the year the tax is incurred as a period expense.

Stockholders' equity

Stockholders' equity	12 Months Ended
	Dec. 31, 2021
Stockholders' equity
Stockholders' equity	10. Stockholders’ equity Preferred Stock As of December 31, 2021, the Company has 50,000,000 shares of preferred stock authorized. There are no shares of preferred stock issued or outstanding Financing 2020 Underwritten Public Offerings In February 2020, the Company completed an underwritten public offering of 2,190,750 shares of its common stock under a universal shelf registration statement for net proceeds of approximately $43.0 million. In May 2020, the Company filed a new universal shelf registration on Form S-3 with the SEC, pursuant to which the Company registered for sale up to $200.0 million of any combination of its common stock, preferred stock, debt securities, warrants, rights and/or units from time to time and at prices and on terms that the Company may determine. As of December 31, 2021, $40.0 million of securities remain available for issuance under the shelf registration statement. In September 2020, the Company completed an underwritten public offering of 4,000,000 shares of its common stock. The Company received net proceeds from this offering of approximately $150.4 million, after deducting underwriting discounts and, commissions but before deducting offering expenses. 2021 At-the-Market Offering Program Sales Agreement In February 2021 the Company filed an automatic shelf registration statement on Form S-3 with the SEC, which became effective upon filing, pursuant to which the Company registered for sale an unlimited amount of any combination of its common stock, preferred stock, debt securities, warrants, rights and/or units from time to time and at prices and on terms that the Company may determine, so long as the Company continued to satisfy the requirements of a “well-known seasoned issuer” under SEC rules. Because the Company is no longer a well-known seasoned issuer, the 2021 Form S-3 will no longer be available for the Company to offer and sell securities pursuant to the 2021 Form S-3 following the filing of this Annual Report on Form 10-K. In February Since the 2021 Form S-3 is no longer available, unless and until the Company registers the offer and sale of securities pursuant to the 2021 Sales Agreement in the future, the Company will not be able to make any further sales of securities under the 2021 Sales Agreement. ​

Stock-based Compensation

Stock-based Compensation	12 Months Ended
	Dec. 31, 2021
Stock-based Compensation
Stock-based Compensation	11. Stock-based Compensation The Company recognized stock-based compensation expense in the accompanying Consolidated Statements of Operations as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, ​ 2021 2020 General and administrative ​ $ 9,715 ​ $ 8,646 Research and development ​ 6,216 5,969 Total stock-based compensation ​ $ 15,931 ​ $ 14,615 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ A summary of the outstanding stock options as of December 31, 2021 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, 2020 ​ 2,371,823 ​ $ 23.89 ​ 7.75 ​ $ 32,764 Granted ​ 938,538 ​ $ 34.17 ​ ​ ​ ​ ​ Expirations/forfeitures ​ (160,623) ​ $ 32.71 ​ ​ ​ ​ ​ Exercises ​ (144,740) ​ $ 13.81 ​ ​ ​ ​ ​ Outstanding—December 31, 2021 ​ 3,004,998 ​ $ 27.10 ​ 7.03 $ 5,232 Exercisable—December 31, 2021 ​ 1,804,047 ​ $ 23.68 ​ 6.03 $ 4,930 Vested or expected to vest at—December 31, 2021 ​ 3,004,998 ​ $ 27.10 ​ 7.03 $ 5,232 ​ 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. As of December 31, 2021, the total unrecognized compensation expense related to unvested options was $26.4 million, which the Company expects to recognize over a weighted average vesting period of 2.58 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. The fair value of share option awards was estimated with the following assumptions: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ As of December 31, ​ ​ 2021 ​ 2020 Price per share of common stock ​ $ 21.60 - 41.71 $ 15.62 - 43.65 Expected term (in years) ​ 6.1 - 6.1 ​ ​ 6.1 - 6.1 ​ Risk-free interest rate ​ 0.50 - 1.4 % ​ 0.35 - 1.7 % Expected volatility ​ 78.20 - 81.5 % ​ 79.41 - 92.9 % Dividend rate ​ 0% ​ ​ 0% ​ ​ Restricted Stock Units Each restricted stock unit (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-line basis over the length of the award. A summary of outstanding RSUs as of December 31, 2021 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ ​ ​ Grant-Date ​ Shares Fair Value Non-vested and outstanding RSU balance at December 31, 2020 ​ 33,065 $ 24.95 Changes during the period: ​ ​ ​ ​ Granted ​ 202,400 24.95 Expirations/forfeitures ​ (23,689) 31.68 Vested ​ (13,687) ​ 25.59 Non-vested and outstanding RSU balance at December 31, 2021 ​ 198,089 $ 33.05 ​ Employee Stock Purchase Plan In June 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 the Company’s stockholders, with The Plan provides for 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. During the years ended December 31, 2021 and 2020,

Summary of significant accoun_2

Summary of significant accounting policies and basis of presentation (Policies)	12 Months Ended
	Dec. 31, 2021
Summary of significant accounting policies and basis of presentation
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).
Principles of consolidation	Principles of consolidation The accompanying Consolidated Financial Statements include the accounts of the Company including 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 subsidiary 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 in 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’s subsidiaries’ 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, 2021 and 2020; 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, realizability of 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 for elobixibat 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 credit risk related to product sales is limited to customers to whom the Company makes significant sales. The Company has no allowance for doubtful accounts. An allowance for doubtful accounts is determined based on the company’s assessment of the credit worthiness and financial condition of its customers, aging of receivables, as well as the general economic environment. Any allowance would reduce the net receivables to the amount that is expected to be collected. For the year ended December 31, 2021 there were 3 customers or collaboration partners who individually accounted for approximately 44%, 35% and 10% of the Company’s gross revenue balance. For the year ended December 31, 2021, there were 3 customers who individually accounted for 43%, 24% and 12% of the Company’s gross accounts receivable balance. The Company believes that credit risks associated with these contracts are not significant due to the customers’ financial strengths. For the year ended December 31, 2020, all revenue and receivables relate to one licensee
Property and equipment, net	Property and equipment, net Property and equipment, including leasehold improvements, are recorded at cost and depreciated when placed into service using the straight-line method, based on their estimated useful lives as follows: ​ ​ ​ ​ ​ ​ Estimated Useful Life Asset Classification (in years) IT Equipment ​ 3 5 Vehicles ​ 5 Leasehold improvements ​ Lesser of useful life or lease term Furniture and fixtures ​ 5 7 ​ Property and equipment purchased for less than $10,000 are expensed immediately. Costs for repairs and maintenance are expensed as incurred. Gains and losses on disposals of equipment are determined by comparing the proceeds with the carrying amount and are recognized within Other operating expense (income), 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, which generally is determined from estimated discounted future net cash flows (assets held for use) or net realizable value (assets held for sale). There were no impairments recorded for the years ended December 31, 2021 and 2020.
Operating Leases	Operating Leases Operating lease assets and liabilities are recognized at the lease commencement date based on the present value of the lease payments over the lease term using the discount rate implicit in the lease. The present value of future lease payments are discounted using the interest rate implicit in lease contracts if that rate is readily determinable; otherwise the Company utilizes its incremental borrowing rate (‘‘IBR’’), which reflects the fixed rate at which the Company could borrow on a collateralized basis over a similar term, the amount of the lease payments in a similar economic environment. Historically, the rate implicit in the leases has not been readily determinable and the appropriate incremental borrowing rate has been utilized. To estimate the appropriate incremental borrowing rate, a credit rating applicable to the Company is estimated using a synthetic credit rating analysis since the Company does not currently have a rating agency-based credit rating.
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 and 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 recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the Company expects to receive in exchange for those goods or services in accordance with ASC 606 Revenue from Contracts with Customers Product Revenue, Net The Company recognizes revenue on sales of Bylvay when a customer obtains control of the product, which occurs at a point in time and upon delivery. The Company sells Bylvay to a limited number of specialty pharmacies and a specialty distributor which dispense the product directly to patients. The specialty pharmacies and specialty distributor are referred to as the Company’s customers. The Company also sells Bylvay to its customers in the European Union, which includes a limited number of pharmacies. The Company provides the right of return to its customers for unopened product for a limited time before and after its expiration date. We currently estimate product returns using available industry data as well as the Company’s visibility into the inventory remaining in the distribution channel. The Company has written contracts with each of its customers that have a single performance obligation to deliver products upon receipt of a customer order and these obligations are satisfied when delivery occurs and the customer receives Bylvay. The Company evaluates creditworthiness of each of its customers to determine whether collection is reasonably assured. The wholesale acquisition cost that the Company charges its customers for Bylvay is adjusted to arrive at our estimated net product revenues by deducting components of variable consideration which include (i) estimated government rebates and discounts related to Medicaid and other government programs, (ii) estimated costs of incentives offered to certain indirect customers including patients, (iii) trade allowances, such as invoice discounts for prompt payment and customer fees, and (iv) allowance for sales returns. Product revenue, net was ​ ​ ​ Rebates and Discounts The Company contracts with the Centers for Medicare & Medicaid Services and other government agencies in the U.S. to make Bylvay available to eligible patients. As a result, the Company estimates any rebates and discounts, including chargebacks related to 340b, and deducts these estimated amounts from its gross product revenues at the time the revenues are recognized. The Company’s estimates of rebates and discounts are based on the government mandated discounts, which are statutorily-defined and applicable to these government funded programs and assumptions developed using historical experience with actual payments and redemptions. The Company recorded $0.7 million and $0.0 million in such estimates as of December 31, 2021 and December 31, 2020, respectively, in accounts receivable, net and other current liabilities on the consolidated balance sheets. The Company contracts with national authorities in Europe to make Bylvay available to eligible patients. In jurisdictions in which final pricing is subject to ongoing negotiations with the government, the Company estimates the rebate expected to be due and deducts these estimated amounts from its gross product revenues at the time the revenues are recognized. The Company’s estimates of such liabilities are based on current invoice pricing and total prior units sold and assumptions developed using benchmarks of Bylvay pricing approved in other relevant European jurisdictions. The Company recorded $0.2 million and $0.0 million in such estimates as of December 31, 2021 and December 31, 2020, respectively, in other current liabilities on the consolidated balance sheets. Other Incentives Other incentives that the Company offers to indirect customers include co-pay assistance cards provided by the Company for patients who reside in states that permit co-pay assistance programs. The Company’s co-pay assistance program is intended to reduce each participating patient’s portion of the financial responsibility for Bylvay’s purchase price to a specified dollar amount. The Company estimates the amount of co-pay assistance provided to eligible patients based on the terms of the program when product is dispensed by the specialty pharmacies to the patients. These estimates are based on redemption information provided by third-party claims processing organizations. The Company funds this incentive program through upfront payments which included a $0.1 million payment in the year ended December 31, 2021. The Company recorded less than $0.1 million and $0.0 million in such estimates as of December 31, 2021 and December 31, 2020, respectively, in prepaid expenses and other current assets on the consolidated balance sheets. Trade Allowances The Company provides invoice discounts on Bylvay sales to its customers for prompt payment and records these discounts as a reduction to gross product revenues. These discounts are based on contractual terms. The Company also pays fees to its distributors for their services as well as data that they provide to the Company. Prompt payment allowances are recorded in accounts receivable, net on the consolidated balance sheets and were less than $0.1 million for the year ended December 31, 2021. The other distributor fees are recorded as other current liabilities on the consolidated balance sheets and were $0.1 million for the year ended December 31, 2021. There were no trade allowances recorded for the year ended December 31, 2020. Trade Receivables, net Accounts receivable, net related to product sales, which are recorded in accounts receivable, net on the consolidated balance sheets, were approximately $3.3 million and $0 million as of December 31, 2021 and December 31, 2020, respectively. As of December 31, 2021 and December 31, 2020, we had no allowance for doubtful accounts. An allowance for doubtful accounts is determined based on the Company’s assessment of the credit worthiness and financial condition of its customers, aging of receivables, as well as the general economic environment. Any allowance would reduce the net receivables to the amount that is expected to be collected. Payment terms for U.S. customers are typically 31 ​ Contract Revenue and Milestone Payments At the inception of each arrangement that includes development milestone payments or upfront payment, the Company evaluates whether the milestones are considered probable of being achieved and estimates the amount to be included in the transaction price, which includes any upfront payments, 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. Once the estimated transaction price is established, the associated consideration is allocated to the performance obligations that have been identified in the respective agreement. 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 has completed all of its performance obligations under the Agreement. As of December 31, 2021, the Company is eligible to receive an additional regulatory-based milestone payment under the Agreement of $4.9 million 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 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.
Monetization of Future Royalties	Monetization of Future Royalties In December 2017, the Company entered into a royalty interest acquisition agreement (RIAA) with HealthCare Royalty Partners III, L.P. (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. In January 2018, the Company received $44.5 million from HCR, net of certain transaction expenses, under the RIAA. On June 8, 2020, the parties entered into an amendment to the RIAA pursuant to which HCR agreed to pay the Company an additional $14.8 million, net of certain transaction expenses, in exchange for the elimination of the (i) $78.8 million cap amount on HCR’s rights to receive royalties on sales in Japan and sales milestones for elobixibat in certain other territories that may become payable by EA Pharma and (ii) the $15.0 million payable to the Company if a specified sales milestone is achieved for elobixibat in Japan. 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 and milestones as revenue. Upon receipt of the payments from HCR the Company recorded net cash totaling $59.3 million as a liability related to sale of future royalties (royalty obligation). The royalty obligation will be amortized using the effective interest rate method. The following table shows the activity within the liability account for the year ended December 31, 2021: ​ ​ ​ ​ ​ ​ ​ December 31, 2021 ​ (in thousands) Liability related to sale of future royalties—beginning balance $ 68,594 Accretion of interest expense on liability related to royalty monetization ​ ​ 12,528 Repayment of the liability ​ ​ (9,455) Liability related to sale of future royalties—ending balance $ 71,667 Less current portion classified within accrued expenses ​ ​ (11,535) Long-term liability related to sale of future royalties $ 60,132 ​ The Company records estimated royalties due for the current period in accrued other expenses until the payment is received from EA Pharma at which time the Company then remits payment to HCR. In order to determine the accretion of the royalty obligation, the Company is required to estimate the total amount of future royalty payments to be received and submitted to HCR. The sum of these amounts less the $59.3 million proceeds the Company received will be recorded as interest expense over the life of the royalty obligation. At December 31, 2021, the Company’s estimate of its total interest expense resulted in an annual effective interest rate of approximately 18.1%. 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.
Inventory	Inventory The Company commenced capitalizing inventory for Bylvay upon FDA approval on July 20, 2021. All commercial manufacturing expenses were expensed as research and development expenses prior to FDA approval. Manufacturing of the Company’s active pharmaceutical ingredient (API) and drug product occurred prior to FDA approval. As a result, manufacturing costs, which totaled approximately $1.6 million, were not capitalized, and instead were expensed as research and development expenses from 2020 until FDA approval in July 2021.
Stock-based compensation	Stock-based compensation The Company accounts for stock-based compensation awards in accordance with FASB ASC Topic 718, Compensation—Stock Compensation 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, 2021 and December 31, 2020, 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.
Employee benefits	Employee benefits Pension obligations The Company has a defined contribution pension plan 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 paid $0.7 million and $0.7 million to the plans for the years ended December 31, 2021 and 2020, 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 $0.7 million and $0.5 million to the plan for the years ended December 31, 2021 and 2020, 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, 2021 and 2020.
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 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, 2021 and 2020, 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 and 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.
Goodwill	Goodwill Goodwill is the excess of the purchase price in a business combination over the fair value of identifiable net assets acquired. Goodwill has an indefinite life and is subject to annual testing for impairment. Goodwill is assessed at least annually, but also whenever events or changes in circumstances indicate the carrying value 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 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. The Company uses its market capitalization as a proxy for its fair value. During the fourth quarter of 2021 and 2020, we completed our annual impairment assessment and concluded that goodwill was not impaired in any of those years.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies and Basis of Presentation (Tables)	12 Months Ended
	Dec. 31, 2021
Summary of significant accounting policies and basis of presentation
Schedule of property and equipment, Useful lives	​ ​ ​ ​ ​ ​ Estimated Useful Life Asset Classification (in years) IT Equipment ​ 3 5 Vehicles ​ 5 Leasehold improvements ​ Lesser of useful life or lease term Furniture and fixtures ​ 5 7
Schedule of Activity within Liability Account from Inception of Royalty Transaction	​ ​ ​ ​ ​ ​ ​ December 31, 2021 ​ (in thousands) Liability related to sale of future royalties—beginning balance $ 68,594 Accretion of interest expense on liability related to royalty monetization ​ ​ 12,528 Repayment of the liability ​ ​ (9,455) Liability related to sale of future royalties—ending balance $ 71,667 Less current portion classified within accrued expenses ​ ​ (11,535) Long-term liability related to sale of future royalties $ 60,132

Fair value of financial instr_2

Fair value of financial instruments (Tables)	12 Months Ended
	Dec. 31, 2021
Fair value of financial instruments
Schedule of financial assets measured at fair value on a recurring basis	The following tables represent information about the Company’s financial assets that are measured at fair value on a recurring basis (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 ​ ​ Level 1 ​ Level 2 ​ Level 3 Cash Equivalents: ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ 243,180 ​ $ — ​ $ — Total ​ $ 243,180 ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ Level 1 ​ Level 2 ​ Level 3 Cash Equivalents: ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ 242,854 ​ $ — ​ $ — Total ​ $ 242,854 ​ $ — ​ $ —

Property and equipment, net (Ta

Property and equipment, net (Tables)	12 Months Ended
	Dec. 31, 2021
Property and equipment, net
Summary of property and equipment, net	Property and equipment, net consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, ​ 2021 2020 IT equipment ​ $ 773 $ 318 Leasehold improvements ​ 58 ​ 58 Furniture and fixtures ​ 450 ​ 453 Total property and equipment, gross ​ 1,281 ​ 829 Less: Accumulated depreciation ​ (613) ​ (351) Total property and equipment, net ​ $ 668 $ 478

Accrued expenses (Tables)

Accrued expenses (Tables)	12 Months Ended
	Dec. 31, 2021
Accrued expenses
Summary of accrued expenses	Accrued expenses consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, ​ 2021 2020 Accrued payroll and benefits ​ $ 10,310 $ 8,492 Accrued professional fees ​ 1,024 ​ 649 Accrued development costs ​ 10,442 ​ 5,968 Accrued liability related to monetization of future royalties ​ 11,535 ​ 2,700 Accrued other ​ 2,640 ​ 1,242 Total accrued expenses ​ $ 35,951 $ 19,051

Commitments and contingencies (

Commitments and contingencies (Tables)	12 Months Ended
	Dec. 31, 2021
Commitments and contingencies
Schedule of contractual obligations under operating leases by period	​ ​ ​ ​ ​ ​ ​ Total Minimum Lease Payments ​ (in thousands) 2022 ​ ​ 1,772 2023 ​ ​ 2,421 2024 ​ ​ 2,466 2025 ​ ​ 2,511 2026 and beyond ​ ​ 7,507 Total minimum lease payments ​ $ 16,677 Less imputed interest ​ ​ (4,463) Total lease liability ​ $ 12,214 ​ ​ ​ ​ Reported as: ​ ​ ​ Other current liabilities ​ $ (1,396) Other long-term liabilities ​ ​ (10,818) Total lease liabilities ​ $ (12,214)

Inventory (Tables)

Inventory (Tables)	12 Months Ended
	Dec. 31, 2021
Inventory
Schedule of inventory	​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 December 31, 2020 Raw materials ​ $ — ​ $ — Work-in-process ​ ​ — ​ ​ — Finished goods ​ ​ 194 ​ ​ — Total inventory ​ $ 194 ​ $ —

Note Payable (Tables)

Note Payable (Tables)	12 Months Ended
	Dec. 31, 2021
Note Payable
Schedule of the carrying value of notes payable	​ ​ ​ ​ ​ ​ ​ December 31, 2021 ​ (in thousands) Note payable, including End of Term Charge ​ ​ 10,695 Debt discount, net of accretion ​ ​ (691) Note payable net of discount, long-term ​ $ 10,004
Schedule of the estimated future principal payments due under the Loan Agreement	​ ​ ​ ​ ​ ​ ​ Note Principal Payments ​ ​ (in thousands) 2022 ​ $ — 2023 ​ ​ 5,254 2024 ​ ​ 5,441

Net loss per share (Tables)

Net loss per share (Tables)	12 Months Ended
	Dec. 31, 2021
Net loss per share
Summary of Computation of Basic EPS and Diluted EPS	The following table sets forth the computation of Basic loss per share and Diluted loss per share (in thousands, except for share and per share data): ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ 2021 2020 Basic and Diluted net loss per share: ​ ​ ​ ​ ​ ​ Numerator ​ ​ ​ ​ ​ ​ Net loss ​ $ (34,030) $ (107,633) Denominator ​ ​ ​ ​ Weighted average number of shares outstanding ​ 19,220,846 ​ ​ 15,983,058 Basic and Diluted loss per share ​ $ (1.77) $ (6.73)
Summary of Outstanding Shares Excluded from Computation of Diluted EPS	​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ 2021 2020 ​ Options to purchase common stock, RSUs and warrants ​ 3,208,398 ​ 2,413,037 ​

Income taxes (Tables)

Income taxes (Tables)	12 Months Ended
	Dec. 31, 2021
Income taxes
Schedule of components of loss before income taxes	For the years ended December 31, 2021 and 2020, the components of loss before income taxes were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, ​ 2021 2020 U.S. ​ $ (18,603) $ (86,041) Foreign ​ (15,427) (21,592) Total ​ $ (34,030) $ (107,633) ​
Schedule of reconciliation of the U.S. statutory income tax rate to the consolidated effective income tax rate	​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ ​ December 31, ​ ​ 2021 2020 ​ U.S. statutory income tax rate ​ 21 % 21 % Stock compensation ​ (3) ​ — ​ State taxes, net of federal tax effect ​ 1 ​ 5 ​ Change in valuation allowance ​ (19) ​ (26) ​ Change in deferred tax rate ​ (1) ​ — ​ Forfeited losses and tax attributes ​ — ​ — ​ Other items ​ 1 ​ — ​ Effective income tax rate ​ 0.0 % 0.0 %
Schedule of tax effect of temporary differences that give rise to significant portions of deferred tax assets	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, ​ 2021 2020 Deferred tax assets: ​ ​ ​ ​ ​ ​ Tax loss carryforwards ​ $ 59,230 $ 59,790 Research and development credits ​ 130 ​ 130 Accrued expenses ​ 1,770 ​ 1,870 Stock compensation ​ 6,790 ​ 4,750 Interest carryforwards ​ ​ 6,670 ​ ​ 4,420 Other ​ 3,150 ​ 1,220 Total gross deferred tax assets ​ 77,740 ​ 72,180 Valuation allowance ​ (74,690) ​ (71,040) Total deferred tax assets ​ $ 3,050 ​ $ 1,140 Deferred tax liabilities: ​ ​ ​ ​ Intangible assets ​ $ (20) $ (20) Right of use asset ​ (3,030) ​ (1,120) Total deferred tax liabilities ​ (3,050) ​ (1,140) Net deferred tax assets ​ $ — $ —

Stock-based Compensation (Table

Stock-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2021
Stock-based Compensation
Summary of stock-based compensation expense	The Company recognized stock-based compensation expense in the accompanying Consolidated Statements of Operations as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, ​ 2021 2020 General and administrative ​ $ 9,715 ​ $ 8,646 Research and development ​ 6,216 5,969 Total stock-based compensation ​ $ 15,931 ​ $ 14,615 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
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, 2020 ​ 2,371,823 ​ $ 23.89 ​ 7.75 ​ $ 32,764 Granted ​ 938,538 ​ $ 34.17 ​ ​ ​ ​ ​ Expirations/forfeitures ​ (160,623) ​ $ 32.71 ​ ​ ​ ​ ​ Exercises ​ (144,740) ​ $ 13.81 ​ ​ ​ ​ ​ Outstanding—December 31, 2021 ​ 3,004,998 ​ $ 27.10 ​ 7.03 $ 5,232 Exercisable—December 31, 2021 ​ 1,804,047 ​ $ 23.68 ​ 6.03 $ 4,930 Vested or expected to vest at—December 31, 2021 ​ 3,004,998 ​ $ 27.10 ​ 7.03 $ 5,232
Schedule of fair value assumptions of share option awards	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ As of December 31, ​ ​ 2021 ​ 2020 Price per share of common stock ​ $ 21.60 - 41.71 $ 15.62 - 43.65 Expected term (in years) ​ 6.1 - 6.1 ​ ​ 6.1 - 6.1 ​ Risk-free interest rate ​ 0.50 - 1.4 % ​ 0.35 - 1.7 % Expected volatility ​ 78.20 - 81.5 % ​ 79.41 - 92.9 % Dividend rate ​ 0% ​ ​ 0% ​
Summary of outstanding RSUs	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ ​ ​ Grant-Date ​ Shares Fair Value Non-vested and outstanding RSU balance at December 31, 2020 ​ 33,065 $ 24.95 Changes during the period: ​ ​ ​ ​ Granted ​ 202,400 24.95 Expirations/forfeitures ​ (23,689) 31.68 Vested ​ (13,687) ​ 25.59 Non-vested and outstanding RSU balance at December 31, 2021 ​ 198,089 $ 33.05

Summary of significant accoun_4

Summary of significant accounting policies and basis of presentation - Segments (Details)	12 Months Ended
	Dec. 31, 2021segment
Segment information
Number of operating segments	1
Number of reportable segments	1

Summary of significant accoun_5

Summary of significant accounting policies and basis of presentation - Concentration of risk (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)customer	Dec. 31, 2020USD ($)customer
Concentration of risk
Allowance for doubtful accounts | $	$ 0	$ 0
Customer Concentration Risk | Revenue from Contract with Customer Benchmark
Concentration of risk
Number of customers	3	1
Customer Concentration Risk | Revenue from Contract with Customer Benchmark | Customer, one
Concentration of risk
Concentration risk, percentage	44.00%
Customer Concentration Risk | Revenue from Contract with Customer Benchmark | Customer, two
Concentration of risk
Concentration risk, percentage	35.00%
Customer Concentration Risk | Revenue from Contract with Customer Benchmark | Customer, three
Concentration of risk
Concentration risk, percentage	10.00%
Customer Concentration Risk | Accounts Receivable
Concentration of risk
Number of customers		1
Credit Concentration Risk | Accounts Receivable
Concentration of risk
Number of customers	3
Credit Concentration Risk | Accounts Receivable | Customer, one
Concentration of risk
Concentration risk, percentage	43.00%
Credit Concentration Risk | Accounts Receivable | Customer, two
Concentration of risk
Concentration risk, percentage	24.00%
Credit Concentration Risk | Accounts Receivable | Customer, three
Concentration of risk
Concentration risk, percentage	12.00%

Summary of significant accoun_6

Summary of significant accounting policies and basis of presentation - Property and equipment (Details)	12 Months Ended
	Dec. 31, 2021USD ($)
Property and equipment, net
Maximum value of computers and other equipment expensed at purchase and not capitalized	$ 10,000
IT equipment | Minimum
Property and equipment, net
Estimated Useful Life	3 years
IT equipment | Maximum
Property and equipment, net
Estimated Useful Life	5 years
Vehicles
Property and equipment, net
Estimated Useful Life	5 years
Furniture and fixtures | Minimum
Property and equipment, net
Estimated Useful Life	5 years
Furniture and fixtures | Maximum
Property and equipment, net
Estimated Useful Life	7 years

Summary of significant accoun_7

Summary of significant accounting policies and basis of presentation - Impairment (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Impairment of long-lived assets
Impairment of long-lived assets	$ 0	$ 0

Summary of significant accoun_8

Summary of significant accounting policies and basis of presentation - Revenue recognition (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Revenue
Revenue	$ 40,579	$ 8,308
Upfront payments for incentive program	100
Prepaid amounts for incentive program		0
Trade allowance		0
Distributor fees	100
Accounts receivable, net	3,272	0
Allowance for doubtful accounts	0	0
Product
Revenue
Revenue	6,993	0
Royalty
Revenue
Revenue	18,586	8,308
Maximum
Revenue
Prepaid amounts for incentive program	100
Trade allowance	100
United States
Revenue
Rebates and discounts	700	0
United States | Product
Revenue
Revenue	$ 5,300
United States | Minimum
Revenue
Payment terms	31 days
United States | Maximum
Revenue
Payment terms	36 days
Europe
Revenue
Rebates and discounts	$ 200	$ 0
Payment terms	45 days
Europe | Product
Revenue
Revenue	$ 1,700
EA Pharma | License Agreement
Revenue
Milestone payment receivable	$ 4,900
Period of written notice required prior to termination of agreement	180 days

Summary of significant accoun_9

Summary of significant accounting policies and basis of presentation - Monetization of future royalties (Details) - USD ($) $ in Thousands	Jun. 08, 2020	Jan. 31, 2018	Dec. 31, 2017	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2020
Summary Of Significant Accounting Policies
Proceeds from sale of future royalties, net					$ 14,750
Liability related to sale of future royalties activity
Accretion of interest expense on liability related to royalty monetization				$ 12,528	10,778
Less current portion classified within accrued expenses				(11,535)	(2,700)	$ (2,700)
Long-term liability related to sale of future royalties				60,132	65,894	65,894
HCR | Royalty Interest Acquisition Agreement
Summary Of Significant Accounting Policies
Maximum royalties under monetization agreement			$ 78,800
Proceeds from sale of future royalties, net	$ 14,800	$ 44,500				59,300
Milestone payment receivable	15,000
Liability related to sale of future royalties activity
Liability related to the sale of future royalties - beginning balance				68,594
Accretion of interest expense on liability related to royalty monetization				12,528
Repayment of the liability				(9,455)
Liability related to sale of future royalties - ending balance				71,667	$ 68,594	$ 68,594
Less current portion classified within accrued expenses				(11,535)
Long-term liability related to sale of future royalties	$ 59,300			$ 60,132
Annual effective interest rate (as a percent)				18.10%

Summary of significant accou_10

Summary of significant accounting policies and basis of presentation - Inventory (Details) $ in Millions	19 Months Ended
	Jul. 31, 2021USD ($)
Research and development
Inventory
Manufacturing costs	$ 1.6

Summary of significant accou_11

Summary of significant accounting policies and basis of presentation - Employee benefits, Income taxes and Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income taxes
Accrued interest or penalties	$ 0	$ 0
Interest and penalties recognized	0	0
Goodwill impairment	0	0
United States
Employee benefits
Employer contributions	$ 0.7	$ 0.5
Maximum employer matching contribution to 401(k) plan, percent	4.00%	4.00%
Sweden-based Plan
Employee benefits
Employer contributions	$ 0.7	$ 0.7

Fair value of financial instr_3

Fair value of financial instruments (Details) - Recurring - Fair Value Level 1 - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Fair Value
Total	$ 243,180	$ 242,854
Money market funds
Fair Value
Cash Equivalents	$ 243,180	$ 242,854

Property and equipment, net (De

Property and equipment, net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Property and equipment, net
Total property and equipment, gross	$ 1,281	$ 829
Less: Accumulated depreciation	(613)	(351)
Total property and equipment, net	668	478
Depreciation expense	300	200
IT equipment
Property and equipment, net
Total property and equipment, gross	773	318
Leasehold improvements
Property and equipment, net
Total property and equipment, gross	58	58
Furniture and fixtures
Property and equipment, net
Total property and equipment, gross	$ 450	$ 453

Accrued expenses - Summary of A

Accrued expenses - Summary of Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accrued expenses
Accrued payroll and benefits	$ 10,310	$ 8,492
Accrued professional fees	1,024	649
Accrued development costs	10,442	5,968
Accrued liability related to monetization of future royalties	11,535	2,700
Accrued other	2,640	1,242
Total accrued expenses	$ 35,951	$ 19,051

Commitments and contingencies -

Commitments and contingencies - Operating leases (Details) $ in Thousands	Mar. 28, 2019USD ($)ft²$ / ft²	Feb. 07, 2017ft²	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 07, 2021ft²	Dec. 06, 2021ft²	May 04, 2020ft²
Commercial real estate leases
Aggregated payments over the term of the lease			$ 16,677
Right of use asset			$ 12,000
Operating Lease, Right-of-Use Asset, Statement of Financial Position			Other assets
Lease cost
Operating lease expense			$ 1,300	$ 1,200
Weighted average remaining lease term for operating leases			7 years 1 month 6 days
Weighted average discount rate (as a percent)				8.77%
Operating lease payments			$ 1,000	$ 1,000
10 Post Office Lease, prior space
Commercial real estate leases
Leased space (in square feet) | ft²		5,116
Existence of option to extend operating lease term		true
Lease renewal term		5 years
10 Post Office lease, new space
Commercial real estate leases
Leased space (in square feet) | ft²	14,734
Annual rent escalation (in dollars per square foot) | $ / ft²	1
Aggregated payments over the term of the lease	$ 12,200
Approximate annual lease payment	$ 1,700
Space subleased (in square feet) | ft²						14,734
10 Post Office Annex Space
Commercial real estate leases
Leased space (in square feet) | ft²							3,490
53 State Street Lease, office space
Commercial real estate leases
Leased space (in square feet) | ft²					26,962

Commitments and contingencies_2

Commitments and contingencies - Lease maturity (Details) $ in Thousands	Dec. 31, 2021USD ($)
Operating lease payments due
2022	$ 1,772
2023	2,421
2024	2,466
2025	2,511
2026 and beyond	7,507
Total minimum lease payments	16,677
Less imputed interest	(4,463)
Total lease liability	12,214
Reported as:
Operating lease liability, current	$ (1,396)
Operating Lease, Liability, Current, Statement of Financial Position	Other current liabilities
Operating lease liability, noncurrent	$ (10,818)
Operating Lease, Liability, Noncurrent, Statement of Financial Position	Other long-term liabilities
Total lease liabilities	$ (12,214)
Operating Lease, Liability, Statement of Financial Position	Other current liabilities, Other long-term liabilities

Commitments and contingencies_3

Commitments and contingencies - Agreements with CROs (Details) $ in Millions	Dec. 31, 2021USD ($)
Commitments and contingencies
Maximum future payable under agreements with CROs	$ 11.8

Inventory (Details)

Inventory (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Inventory
Finished goods	$ 194
Total inventory	194
Inventory write downs	$ 0	$ 0
Finished goods inventory shelf life	24 months

Note Payable - Loan and Securit

Note Payable - Loan and Security Agreement (Details) - USD ($) $ in Millions	Jun. 08, 2020	Dec. 31, 2021
Loan and Security Agreement, Term Loans
Debt instrument
Maximum borrowing capacity	$ 80
End of term charge as a percent of principal amount	6.95%
Prepayment premium, as a percent of principal, between 9 months and 24 months following closing date	2.00%
Prepayment premium, as a percent of principal, 24 months following closing date and before maturity date	1.00%
Effective interest rate (as a percent)		13.00%
Loan and Security Agreement, Term Loans | Minimum
Debt instrument
Interest rate percentage added to variable rate to determine minimum annual interest rate	9.15%
Loan and Security Agreement, Term Loans | Prime Rate
Debt instrument
Interest rate percentage added to variable rate to determine minimum annual interest rate	9.15%
Spread on rate (as a percent)	3.25%
Loan and Security Agreement, Term Loan, First/Initial Tranche
Debt instrument
Maximum borrowing capacity	$ 10
Loan and Security Agreement, Term Loan, Second Tranche
Debt instrument
Maximum borrowing capacity	20
Minimum borrowing increments	10
Loan and Security Agreement, Term Loan, Third Tranche
Debt instrument
Maximum borrowing capacity, term loan advance	45
Minimum borrowing increments	$ 5

Note Payable - Carrying Value (

Note Payable - Carrying Value (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Note payable net of discount, long-term	$ 10,004	$ 9,621
Loan and Security Agreement, Term Loans
Debt Instrument [Line Items]
Note payable, including End of Term Charge	10,695
Debt discount, net of accretion	(691)
Note payable net of discount, long-term	10,004
Interest expense	1,300	800
Amount borrowed	10,000	10,000
Debt discount and issuance costs	$ 400	$ 200

Note Payable - Estimated future

Note Payable - Estimated future principal payments (Details) - Loan and Security Agreement, Term Loans $ in Thousands	Dec. 31, 2021USD ($)
Debt Instrument [Line Items]
2023	$ 5,254
2024	$ 5,441

Note Payable - Warrants (Detail

Note Payable - Warrants (Details) - USD ($) $ / shares in Units, $ in Millions	Jun. 08, 2020	Dec. 31, 2021	Dec. 31, 2020
Warrants
Common stock, par value (in dollars per share)		$ 0.01	$ 0.01
Loan and Security Agreement, Term Loans
Warrants
Number of warrants (as a percent)	1.00%
Number of warrants issued (in shares)	5,311
Warrant exercise period	7 years
Warrants exercise price (in dollars per share)	$ 18.83
Warrant registration period	60 days
Loan and Security Agreement, Term Loans | Maximum
Warrants
Warrant registration period	180 days
Loan and Security Agreement, Term Loan, First/Initial Tranche
Warrants
Fair value of warrants	$ 0.1

Net loss per share - Basic and

Net loss per share - Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Basic and Diluted net loss per share - Numerator
Net income (loss), Basic	$ (34,030)	$ (107,633)
Net income (loss), Diluted	$ (34,030)	$ (107,633)
Denominator - Weighted average number of shares outstanding
Weighted average number of shares outstanding, basic	19,220,846	15,983,058
Weighted average number of shares outstanding, diluted	19,220,846	15,983,058
Basic net income (loss) per share (in dollars per share)	$ (1.77)	$ (6.73)
Diluted net income (loss) per share (in dollars per share)	$ (1.77)	$ (6.73)

Net loss per share - Anti-dilut

Net loss per share - Anti-dilutive shares (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Options to purchase common stock and RSUs
Antidilutive Securities
Anti-dilutive securities excluded from computation of diluted net loss per share	3,208,398	2,413,037

Income taxes - Components of lo

Income taxes - Components of loss before income taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income taxes
Current tax provision	$ 0	$ 0
Deferred tax provision	0	0
U.S. loss before income taxes	(18,603)	(86,041)
Foreign loss before income taxes	(15,427)	(21,592)
Net income (loss) before income taxes	$ (34,030)	$ (107,633)

Income taxes - Reconciliation o

Income taxes - Reconciliation of statutory income tax rate (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income taxes
U.S. statutory income tax rate	21.00%	21.00%
Stock compensation	(3.00%)
State taxes, net of federal tax effect	1.00%	5.00%
Change in valuation allowance	(19.00%)	(26.00%)
Change in deferred tax rate	(1.00%)
Other items	1.00%
Effective income tax rate	0.00%	0.00%

Income taxes - Deferred tax ass

Income taxes - Deferred tax assets and liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Tax loss carryforwards	$ 59,230	$ 59,790
Research and development credits	130	130
Accrued expenses	1,770	1,870
Stock compensation	6,790	4,750
Interest carryforwards	6,670	4,420
Other	3,150	1,220
Total gross deferred tax assets	77,740	72,180
Valuation allowance	(74,690)	(71,040)
Total deferred tax assets	3,050	1,140
Deferred tax liabilities:
Intangible assets	(20)	(20)
Right of use asset	(3,030)	(1,120)
Total deferred tax liabilities	(3,050)	(1,140)
Net deferred tax assets
Valuation allowance
Change in valuation allowance	$ 3,700	$ 31,100

Income taxes - Operating Losses

Income taxes - Operating Losses and Uncertain tax positions (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Net operating loss carryforwards
Tax loss carryforwards	$ 59,230	$ 59,790
U.S. Federal Tax
Net operating loss carryforwards
Tax loss carryforwards subject to expiration	1,500
Tax loss carryforwards with no expiration date	98,800
U.S. State Tax
Net operating loss carryforwards
Net operating loss	246,300
Non-U.S. Jurisdictions
Net operating loss carryforwards
Net operating loss	$ 112,500

Income taxes - Uncertain tax be

Income taxes - Uncertain tax benefits (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Uncertain tax positions
Uncertain tax benefits recognized	$ 0	$ 0

Stockholders' Equity - Preferre

Stockholders' Equity - Preferred Stock (Details) - shares	Dec. 31, 2021	Dec. 31, 2020
Preferred Stock
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0

Stockholders' Equity - Financin

Stockholders' Equity - Financing (Details) - USD ($) $ in Thousands	1 Months Ended			12 Months Ended
	Jul. 31, 2021	Sep. 30, 2020	Feb. 29, 2020	Dec. 31, 2021	Dec. 31, 2020	Feb. 28, 2021	May 31, 2020
Equity
Proceeds from issuance of common stock, net of issuance costs				$ 241	$ 193,265
Underwritten Public Offering, February 2020
Equity
Issuance of common stock (in shares)			2,190,750
Proceeds from issuance of common stock, net of issuance costs			$ 43,000
Universal Shelf Registration, May 2020
Equity
Aggregate offering price							$ 200,000
Number of securities available for issuance				40,000,000
Underwritten Public Offering, September 2020
Equity
Issuance of common stock (in shares)		4,000,000
Proceeds from issuance of common stock, before deducting offering costs		$ 150,400
2021 Sales Agreement, At-the-Market Offering
Equity
Issuance of common stock (in shares)	7,508
Proceeds from issuance of common stock, net of issuance costs	$ 200
2021 Sales Agreement, At-the-Market Offering | Maximum
Equity
Aggregate offering price						$ 100,000

Stock-based Compensation - Stoc

Stock-based Compensation - Stock-based compensation expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Stock-based compensation
Stock-based compensation expense	$ 15,931	$ 14,615
General and administrative
Stock-based compensation
Stock-based compensation expense	9,715	8,646
Research and development
Stock-based compensation
Stock-based compensation expense	$ 6,216	$ 5,969

Stock-based Compensation - Summ

Stock-based Compensation - Summary of Outstanding Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Number of Shares
Outstanding - Beginning balance (in shares)	2,371,823
Granted (in shares)	938,538
Expirations/forfeitures (in shares)	(160,623)
Exercises (in shares)	(144,740)
Outstanding - Ending balance (in shares)	3,004,998	2,371,823
Exercisable (in shares)	1,804,047
Vested or expected to vest (in shares)	3,004,998
Weighted-Average Exercise Price Per Share
Outstanding - Beginning balance (in dollars per share)	$ 23.89
Granted (in dollars per share)	34.17
Expirations/forfeitures (in dollars per share)	32.71
Exercises (in dollars per share)	13.81
Outstanding - Ending balance (in dollars per share)	27.10	$ 23.89
Exercisable (in dollars per share)	23.68
Vested or expected to vest (in dollars per share)	$ 27.10
Weighted- Average Remaining Contractual Term
Outstanding (Years)	7 years 10 days	7 years 9 months
Exercisable (Years)	6 years 10 days
Vested or expected to vest (Years)	7 years 10 days
Aggregate Intrinsic Value
Outstanding (in dollars)	$ 5,232	$ 32,764
Exercisable options (in dollars)	4,930
Vested or expected to vest (in dollars)	$ 5,232

Stock-based Compensation - St_2

Stock-based Compensation - Stock Options - Additional information (Details) - Employee Stock Option $ in Millions	12 Months Ended
	Dec. 31, 2021USD ($)
Stock-based Compensation
Total unrecognized compensation expense related to unvested options	$ 26.4
Weighted average vesting period for unvested options	2 years 6 months 29 days

Stock-based Compensation - Fair

Stock-based Compensation - Fair value assumptions of stock option awards (Details) - Employee Stock Option - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Fair value assumptions
Dividend rate (as a percent)	0.00%	0.00%
Minimum
Fair value assumptions
Price per share of common stock (in dollars per share)	$ 21.60	$ 15.62
Expected term (in years)	6 years 1 month 6 days	6 years 1 month 6 days
Risk-free interest rate (as a percent)	0.50%	0.35%
Expected volatility (as a percent)	78.20%	79.41%
Maximum
Fair value assumptions
Price per share of common stock (in dollars per share)	$ 41.71	$ 43.65
Expected term (in years)	6 years 1 month 6 days	6 years 1 month 6 days
Risk-free interest rate (as a percent)	1.40%	1.70%
Expected volatility (as a percent)	81.50%	92.90%

Stock-based Compensation - Rest

Stock-based Compensation - Restricted Stock Units (Details) - RSUs	12 Months Ended
	Dec. 31, 2021$ / 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
Non-vested and outstanding balance, beginning of period (in shares)	33,065
Granted (in shares)	202,400
Expirations/forfeitures (in shares)	(23,689)
Vested (in shares)	(13,687)
Non-vested and outstanding balance, end of period (in shares)	198,089
Weighted Average Grant-Date Fair Value
Non-vested and outstanding balance, beginning of period (in dollars per share) | $ / shares	$ 24.95
Granted (in dollars per share) | $ / shares	24.95
Expirations/forfeitures (in dollars per share) | $ / shares	31.68
Vested (in dollars per share) | $ / shares	25.59
Non-vested and outstanding balance, end of period (in dollars per share) | $ / shares	$ 33.05

Stock-based Compensation - Empl

Stock-based Compensation - Employee Stock Purchase Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Jun. 30, 2018
Employee Stock Purchase Plan
Stock-based compensation expense	$ 15,931	$ 14,615
2018 Employee Stock Purchase Plan
Employee Stock Purchase Plan
Offering period	6 months
Shares purchased (in shares)	31,337	14,270
Shares available to be issued under the ESPP	246,039		300,000
Stock-based compensation expense	$ 300	$ 100