| Summary of Significant Accounting Policies (Policies) | 12 Months Ended |
| Dec. 31, 2018 |
| Accounting Policies [Abstract] | |
| Basis of Presentation and Principles of Consolidation | Basis of Presentation and Principles of Consolidation The consolidated financial statements of the Company have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). The consolidated financial statements include the financial statements of the Company and its subsidiaries. All significant intercompany transactions and balances between the Company and its wholly-owned subsidiaries are eliminated upon consolidation. Noncontrolling interests are recognized to reflect the portion of the equity of subsidiaries which are not attributable, directly or indirectly, to the controlling shareholders. The Company consolidates its interests in its joint venture, BeiGene Biologics, under the voting model and recognizes the minority shareholder's equity interest as a noncontrolling interest in its consolidated financial statements (as described in Note 8). |
| Use of Estimates | Use of Estimates The preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the period. Areas where management uses subjective judgment include, but are not limited to, estimating the useful lives of long-lived assets, estimating variable consideration in product sales and collaboration revenue arrangements, identifying separate accounting units and the standalone selling price of each performance obligation in the Company’s revenue arrangements, estimating the fair value of net assets acquired in business combinations, assessing the impairment of long-lived assets, share-based compensation expenses, realizability of deferred tax assets, estimating uncertain tax positions and the fair value of financial instruments. Management bases the estimates on historical experience, known trends and various other assumptions that are believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities. Actual results could differ from these estimates. |
| Functional Currency and Foreign Currency Translation | Functional Currency and Foreign Currency Translation Functional currency The determination of the respective functional currency is based on the criteria of Accounting Standard Codification (“ASC”) 830, Foreign Currency Matters. The functional currency of the Company and all non-PRC subsidiaries is the United States dollar (“$” or “U.S. dollar”). The Company’s PRC subsidiaries determined their functional currencies to be RMB. The Company uses the U.S. dollar as its reporting currency. Foreign currency translation For subsidiaries whose functional currencies are not the U.S. dollar, the Company uses the average exchange rate for the year and the exchange rate at the balance sheet date, to translate the operating results and financial position to U.S. dollar, the reporting currency, respectively. Translation differences are recorded in accumulated other comprehensive loss, a component of shareholders’ equity. Transactions denominated in currencies other than the functional currency are translated into the functional currency at the exchange rates prevailing on the transaction dates. Foreign currency denominated financial assets and liabilities are remeasured at the exchange rates prevailing at the balance sheet date. Exchange gains and losses are included in the consolidated statements of comprehensive loss. |
| Cash and Cash Equivalents | Cash and cash equivalents Cash and cash equivalents consist of cash on hand and bank deposits, which are unrestricted as to withdrawal and use. The Company considers all highly liquid investments with an original maturity date of three months or less at the date of purchase to be cash equivalents. Cash equivalents which consist primarily of money market funds are stated at fair value. |
| Restricted Cash | Restricted cash Restricted cash consists of the secured deposits held in designated banks for issuance of letters of credit and import duty taxes, and cash deposits as security for long-term bank loans. |
| Accounts Receivable | Accounts Receivable Trade accounts receivable are recorded at their invoiced amounts, net of allowances for doubtful accounts. An allowance for doubtful accounts is recorded when the collection of the full amount is no longer probable. In evaluating the collectability of receivable balances, the Company considers specific evidence including aging of the receivable, the customer's payment history, its current creditworthiness and current economic trends. Accounts receivable are written off after all collection efforts have ceased. The Company regularly reviews the adequacy and appropriateness of any allowance for doubtful accounts. No allowance for doubtful accounts was recorded as of December 31, 2018 . |
| Inventory | Inventory Inventories are stated at the lower of cost and net realizable value, with cost determined on a weighted-average basis. The Company periodically analyzes its inventory levels, and writes down inventory that has become obsolete, inventory that has a cost basis in excess of its estimated realizable value and inventory in excess of expected sales requirements as cost of product sales. The determination of whether inventory costs will be realizable requires estimates by management. If actual market conditions are less favorable than projected by management, additional write-downs of inventory may be required, which would be recorded in the consolidated statements of operations. There have been no write-downs or reserves against inventory to date. |
| Short-Term Investments | Short-Term Investments Investments with original maturities of greater than three months at the date of purchase and less than one year from the date of the balance sheet are classified as short-term. Short-term debt investments held to maturity are carried at amortized cost when the Company has the ability and positive intent to hold these securities until maturity. When the Company does not have the ability or positive intent to hold short-term debt investments until maturity, these securities are classified as available-for-sale. None of the Company’s fixed maturity securities met the criteria for held-to-maturity classification at December 31, 2018 and 2017 . Available-for-sale securities are stated at fair value, with the unrealized gains and losses, net of tax, reported in other comprehensive loss. The net carrying value of debt securities classified as available-for-sale is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization is computed using the effective interest method and included in interest income. Interest and dividends are included in interest income. When the fair value of a debt security classified as available-for-sale is less than its amortized cost, the Company assesses whether or not: (i) it has the intent to sell the security or (ii) it is more likely than not that the Company will be required to sell the security before its anticipated recovery. If either of these conditions is met, the Company must recognize an other-than-temporary impairment through earnings for the difference between the debt security’s amortized cost basis and its fair value. No impairment losses were recorded for any periods presented. The cost of securities sold is based on the specific identification method. |
| Property and Equipment | Property and Equipment Property and equipment are stated at cost, less accumulated depreciation and amortization. Depreciation is computed using the straight-line method over the estimated useful lives of the respective assets as follows: Useful Life Building 20 years Office Equipment 5 years Electronic Equipment 3 years Manufacturing equipment 3 to 10 years Laboratory Equipment 3 to 5 years Computer Software 3 to 5 years Leasehold Improvements Lesser of useful life or lease term |
| Land Use Right, Net | Land Use Right, Net All land in the PRC is owned by the PRC government. The PRC government may sell land use rights for a specified period of time. Land use rights represent lease prepayments to the PRC government and are carried at cost less accumulated amortization. Land use rights are amortized on a straight-line basis over the shorter of the estimated usage periods or the terms of the land use right. In 2017, the Company acquired a land use right from the local Bureau of Land and Resources in Guangzhou for the purpose of constructing and operating the biologics manufacturing facility in Guangzhou. The Guangzhou land use right is being amortized over the terms of the land use right, which is 50 years. |
| Business Combination | Business Combinations The Company accounts for its business combinations using the acquisition method of accounting in accordance with ASC topic 805 (“ASC 805”): Business Combinations. The acquisition method of accounting requires all of the following steps: (i) identifying the acquirer, (ii) determining the acquisition date, (iii) recognizing and measuring the identifiable assets acquired, the liabilities assumed, and any noncontrolling interest in the acquiree, and (iv) recognizing and measuring goodwill or a gain from a bargain purchase. The consideration transferred in a business combination is measured as the aggregate of the fair values at the date of exchange of the assets given, liabilities incurred, and equity instruments issued as well as the contingent considerations and all contractual contingencies as of the acquisition date. The costs directly attributable to the acquisition are expensed as incurred. Identifiable assets, liabilities and contingent liabilities acquired or assumed are measured separately at their fair value as of the acquisition date, irrespective of the extent of any noncontrolling interests. The excess of (i) acquisition consideration, fair value of the noncontrolling interests and acquisition date fair value of any previously held equity interest in the acquiree over (ii) the fair value of the identifiable net assets of the acquiree, is recorded as goodwill. If the cost of acquisition is less than the fair value of the net assets of the subsidiary acquired, the difference is recognized directly in the consolidated statements of operations as a gain. The Company allocates the fair value of purchase consideration to the tangible assets acquired, liabilities assumed and intangible assets acquired based on their estimated fair values. The excess of the fair value of purchase consideration over the fair values of these identifiable assets and liabilities is recorded as goodwill. Such valuations require management to make significant estimates and assumptions, especially with respect to intangible assets. Significant estimates in valuing certain intangible assets may include, but are not limited to, future expected cash flows from acquired assets, timing and probability of success of clinical events and regulatory approvals, and assumptions on useful lives and discount rates. Management's estimates of fair value are based upon assumptions believed to be reasonable, but which are inherently uncertain and unpredictable and, as a result, actual results may differ from estimates. Additional information, such as that related to income tax and other contingencies, existing as of the acquisition date but unknown to us may become known during the remainder of the measurement period, not to exceed one year from the acquisition date, which may result in changes to the amounts and allocations recorded. Acquisitions that do not meet the accounting definition of a business combination are accounted for as asset acquisitions. For transactions determined to be asset acquisitions, the Company allocates the total cost of the acquisition, including transaction costs, to the net assets acquired based on their relative fair values. |
| Goodwill and Other Intangible Assets | Goodwill and Other Intangible Assets Goodwill is an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. The Company allocates the cost of an acquired entity to the assets acquired and liabilities assumed based on their estimated fair values at the date of acquisition. The excess of the purchase price for acquisitions over the fair value of the net assets acquired, including other intangible assets, is recorded as goodwill. Goodwill is not amortized, but is tested for impairment at least annually or more frequently if events or changes in circumstances would indicate a potential impairment. The Company has elected to first assess qualitative factors to determine whether it is more likely than not that the fair value of the Company's reporting unit is less than its carrying amount, including goodwill. The qualitative assessment includes the Company's evaluation of relevant events and circumstances affecting the Company's single reporting unit, including macroeconomic, industry, and market conditions, the Company's overall financial performance, and trends in the market price of the Company's ADSs. If qualitative factors indicate that it is more likely than not that the Company's reporting unit’s fair value is less than its carrying amount, then the Company will perform the quantitative impairment test by comparing the reporting unit’s carrying amount, including goodwill, to its fair value. If the carrying amount of the reporting unit exceeds its fair value, an impairment loss will be recognized in an amount equal to that excess. For the year ended December 31, 2018 , the Company determined that there were no indicators of impairment of our goodwill. Intangible assets acquired through business combinations are recognized as assets separate from goodwill and are measured at fair value upon acquisition. Intangible assets acquired in transactions that are not business combinations are recorded at the allocated portion of total consideration transferred based on their relative fair value in relation to net assets acquired. Acquired identifiable intangible assets consist of distribution rights for approved cancer therapies licensed from Celgene Corporation ("Celgene"), ABRAXANE®, REVLIMID®, and VIDAZA®, and its investigational agent CC-122, and are amortized on a straight-line basis over the estimated useful lives of the assets, which is 10 years, and the trading license which represents the Guangzhou drug distribution license acquired on September 21, 2018 (see Note 4). The Company is amortizing the trading license over the remainder of the license term through February 2020. Intangible assets with finite useful lives are tested for impairment when events or circumstances occur that could indicate that the carrying amount of an asset may not be recoverable. When these events occur, the Company evaluates the recoverability of the intangible assets by comparing the carrying amount of the assets to the future undiscounted cash flows expected to result from the use of the assets and their eventual disposition. If the sum of the expected undiscounted cash flows is less than the carrying amount of the assets, the Company recognizes an impairment loss based on the excess of the carrying amount of the assets over their fair value. Fair value is generally determined by discounting the cash flows expected to be generated by the assets, when the market prices are not readily available. For the years ended December 31, 2018 and December 31, 2017, the Company determined that there were no indicators of impairment of its other intangible assets. |
| Impairment of Long-Lived Assets | Impairment of Long-Lived Assets Long-lived assets are reviewed for impairment in accordance with authoritative guidance for impairment or disposal of long-lived assets. Long-lived assets are reviewed for events or changes in circumstances, which indicate that their carrying value may not be recoverable. Long-lived assets are reported at the lower of carrying amount or fair value less cost to sell. For the years ended December 31, 2018 , 2017 and 2016 , there was no impairment of the value of the Company’s long-lived assets. |
| Fair Value Measurements | Fair Value Measurements Fair value of financial instruments Financial instruments of the Company primarily include cash and cash equivalents, restricted cash, short-term investments, accounts receivable, long-term bank loan, Shareholder Loan (as defined in Note 16) and accounts payable. As of December 31, 2018 and 2017 , the carrying values of cash and cash equivalents, restricted cash, accounts receivable and accounts payable approximated their fair values due to the short-term maturity of these instruments. The short-term investments represented the available-for-sale debt securities and time deposits. The available-for-sale debt securities are recorded at fair value based on quoted prices in active markets with unrealized gain or loss recorded in other comprehensive loss. The long-term bank loan and Shareholder Loan approximate their fair value due to the fact that the related interest rates approximate the rates currently offered by financial institutions for similar debt instrument of comparable maturities. The Company applies ASC topic 820 (“ASC 820”), Fair Value Measurements and Disclosures, in measuring fair value. ASC 820 defines fair value, establishes a framework for measuring fair value and requires disclosures to be provided on fair value measurement. ASC 820 establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows: Level 1—Observable inputs that reflect quoted prices (unadjusted) for identical assets or liabilities in active markets. Level 2—Include other inputs that are directly or indirectly observable in the marketplace. Level 3—Unobservable inputs which are supported by little or no market activity. ASC 820 describes three main approaches to measuring the fair value of assets and liabilities: (1)market approach; (2) income approach and (3) cost approach. The market approach uses prices and other relevant information generated from market transactions involving identical or comparable assets or liabilities. The income approach uses valuation techniques to convert future amounts to a single present value amount. The measurement is based on the value indicated by current market expectations about those future amounts. The cost approach is based on the amount that would currently be required to replace an asset. |
| Revenue Recognition | Revenue Recognition Effective January 1, 2018, the Company adopted Accounting Standards Codification, Topic 606, Revenue from Contracts with Customers (“ASC 606”) using the modified retrospective method. For further information regarding the impact of adoption, see Note 2 Recent Accounting Pronouncements . Under ASC 606, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration that the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of ASC 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price, including variable consideration, if any; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The Company only applies the five-step model to contracts when it is probable that the entity will collect the consideration to which it is entitled in exchange for the goods or services it transfers to the customer. Once a contract is determined to be within the scope of ASC 606 at contract inception, the Company reviews the contract to determine which performance obligations it must deliver and which of these performance obligations are distinct. The Company recognizes as revenue the amount of the transaction price that is allocated to each performance obligation when that performance obligation is satisfied or as it is satisfied. Product revenue The Company's product revenues are generated from the sale of ABRAXANE®, REVLIMID®, and VIDAZA® to its product distributor in China. The distributor subsequently resells the products to second tier distributors who ultimately sell the products to health care providers and patients. The Company is the principal under the product sale as the Company controls the products with the ability to direct the use of, and obtain substantially all the remaining benefits from the products before they are sold to its first tier distributer. The Company has a single performance obligation which is to sell the products to its first tier distributer. The Company includes variable consideration in the transaction price to the extent it is probable that a significant reversal will not occur and estimates variable consideration from sales rebates and returns using the expected value method. Revenues for product sales are recognized at a point in time when the single performance obligation is satisfied upon delivery to the first tier distributer. The Company's payment terms are approximately 90 days. Actual amounts of consideration ultimately received may differ from the Company’s estimates. The Company will reassess estimates for variable consideration periodically. If actual results in the future vary from the Company’s estimates, the Company will adjust these estimates, which would affect net product revenue and earnings in the period such variances become known. Rebates, including price compensation credits, are offered to distributors, consistent with pharmaceutical industry practices. The Company records a provision for rebates at the time of sale based on contracted rates and historical redemption rates. Assumptions used to establish the provision include the level of distributor inventories, sales volumes and contract pricing and estimated acceptance of government pricing or reimbursement amounts (such as provincial acceptance of the National Reimbursement Drug List pricing in the PRC). The Company regularly reviews the information related to these estimates and adjust the provision accordingly. To date, rebates have not been significant. The Company bases its sales returns allowance on estimated distributor inventories, customer demand as reported by third-party sources, and actual returns history, as well as other factors, as appropriate. If the historical data the Company uses to calculate these estimates do not properly reflect future returns, then a change in the allowance would be made in the period in which such a determination is made and revenues in that period could be materially affected. Any changes from the historical trend rates are considered in determining the current sales return allowance. To date, sales returns have not been significant. Collaboration revenue At contract inception, the Company analyzes its collaboration arrangements to assess whether they are within the scope of ASC 808, Collaborative Arrangements (“ASC 808”) to determine whether such arrangements involve joint operating activities performed by parties that are both active participants in the activities and exposed to significant risks and rewards dependent on the commercial success of such activities. For collaboration arrangements within the scope of ASC 808 that contain multiple elements, the Company first determines which elements of the collaboration are deemed to be within the scope of ASC 808 and those that are more reflective of a vendor-customer relationship and therefore within the scope of ASC 606. For elements of collaboration arrangements that are accounted for pursuant to ASC 808, an appropriate recognition method is determined and applied consistently. In determining the appropriate amount of revenue to be recognized as it fulfills its obligations under each of its agreements, the Company performs the five step model under ASC 606 noted above. The Company’s collaborative arrangements may contain more than one unit of account, or performance obligation, including grants of licenses to intellectual property rights, agreement to provide research and development services and other deliverables. The collaborative arrangements do not include a right of return for any deliverable. As part of the accounting for these arrangements, the Company must develop assumptions that require judgment to determine the stand-alone selling price for each performance obligation identified in the contract. In developing the stand-alone selling price for a performance obligation, the Company considers competitor pricing for a similar or identical product, market awareness of and perception of the product, expected product life and current market trends. In general, the consideration allocated to each performance obligation is recognized when the respective obligation is satisfied either by delivering a good or providing a service, limited to the consideration that is not constrained. Non-refundable payments received before all of the relevant criteria for revenue recognition are satisfied are recorded as advances from customers. Licenses of Intellectual Property: Upfront non-refundable payments for licensing the Company’s intellectual property are evaluated to determine if the license is distinct from the other performance obligations identified in the arrangement. For licenses determined to be distinct, the Company recognizes revenues from non-refundable, up-front fees allocated to the license at a point in time, when the license is transferred to the licensee and the licensee is able to use and benefit from the license. Research and Development Services: The portion of the transaction price allocated to research and development services performance obligations is deferred and recognized as collaboration revenue over time as delivery or performance of such services occurs. R&D reimbursement revenue for revenue attributable to the clinical trials that Celgene has opted into is recognized as delivery or performance of such services occurs. Milestone Payments: At the inception of each arrangement that includes development milestone payments, the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestones related to the Company’s development-based activities may include initiation of various phases of clinical trials. Due to the uncertainty involved in meeting these development-based targets, they are generally fully constrained at contract inception. The Company will assess whether the variable consideration is fully constrained each reporting period based on the facts and circumstances surrounding the clinical trials. Upon changes to constraint associated with the developmental milestones, variable consideration will be included in the transaction price when a significant reversal of revenue recognized is not expected to occur and allocated to the separate performance obligations. Regulatory milestones are fully constrained until the period in which those regulatory approvals are achieved due to the inherent uncertainty with the approval process. Regulatory milestones are included in the transaction price in the period regulatory approval is obtained. Royalties: For arrangements that include sales-based royalties, including milestone payments based on the 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). |
| Research and Development Expenses | Research and Development Expenses Research and development expenses represent costs associated with the collaborative arrangements, which primarily include (i) payroll and related costs (including share-based compensation) associated with research and development personnel, (ii) costs related to clinical trials and preclinical testing of the Company’s technologies under development, (iii) costs to develop the product candidates, including raw materials and supplies, product testing, depreciation, and facility related expenses, (iv) expenses for research services provided by universities and contract laboratories, including sponsored research funding, and (v) other research and development expenses. Research and development expenses are charged to expense as incurred when these expenditures relate to the Company’s research and development services and have no alternative future uses. Clinical trial costs are a significant component of the Company’s research and development expenses. The Company has a history of contracting with third parties that perform various clinical trial activities on behalf of the Company in the ongoing development of the Company’s product candidates. Expenses related to clinical trials are accrued based on the Company’s estimates of the actual services performed by the third parties for the respective period. If the contracted amounts are modified (for instance, as a result of changes in the clinical trial protocol or scope of work to be performed), the Company will modify the related accruals accordingly on a prospective basis. Revisions in the scope of a contract are charged to expense in the period in which the facts that give rise to the revision become reasonably certain. There were no material adjustments for a change in estimate to research and development expenses in the accompanying consolidated financial statements for the years ended December 31, 2018 , 2017 and 2016 . Acquired In-Process Research and Development Expense The Company has acquired rights to develop and commercialize product candidates. Upfront payments that relate to the acquisition of a new drug compound, as well as pre-commercial milestone payments, are immediately expensed as acquired in-process research and development in the period in which they are incurred, provided that the new drug compound did not also include processes or activities that would constitute a “business” as defined under GAAP, the drug has not achieved regulatory approval for marketing and, absent obtaining such approval, has no established alternative future use. Milestone payments made to third parties subsequent to regulatory approval are capitalized as intangible assets and amortized over the estimated remaining useful life of the related product. Royalties owed on sales of the products licensed pursuant to the agreements are expensed in the period the related revenues are recognized. |
| Government Grants | Government Grants Government financial incentives that involve no conditions or continuing performance obligations of the Company are recognized as other non-operating income upon receipt. In the event government grants or incentives involve continuing performance obligations, the Company will capitalize the payment as a liability and recognize the same financial statement caption as the performance obligation relates over the performance period. |
| Leases | Leases Leases are classified at the inception date as either a capital lease or an operating lease. The Company assesses a lease to be a capital lease if any of the following conditions exist: (a) ownership is transferred to the lessee by the end of the lease term, (b) there is a bargain purchase option, (c) the lease term is at least 75% of the property’s estimated remaining economic life, or (d) the present value of the minimum lease payments at the beginning of the lease term is 90% or more of the fair value of the leased property to the lessor at the inception date. A capital lease is accounted for as if there was an acquisition of an asset and an occurrence of an obligation at the inception of the lease. The Company has no capital leases for the years presented. All other leases are accounted for as operating leases wherein rental payments are expensed on a straight-line basis over the periods of their respective lease terms. The Company leases office space, employee accommodation and manufactory space under operating lease agreements. Certain of the lease agreements contain rent holidays. Rent holidays are considered in determining the straight-line rent expense to be recorded over the lease term. The lease term begins on the date of initial possession of the lease property for purposes of recognizing lease expense on straight-line basis over the term of the lease. |
| Comprehensive Loss | Comprehensive Loss Comprehensive loss is defined as the changes in equity of the Company during a period from transactions and other events and circumstances excluding transactions resulting from investments by owners and distributions to owners. Among other disclosures, ASC 220, Comprehensive Income, requires that all items that are required to be recognized under current accounting standards as components of comprehensive loss be reported in a financial statement that is displayed with the same prominence as other financial statements. For each of the periods presented, the Company’s comprehensive loss includes net loss, foreign currency translation adjustments and unrealized holding gains/losses associated with the available-for-sale securities, and is presented in the consolidated statements of comprehensive loss. |
| Share-Based Compensation | Share-Based Compensation Awards granted to employees The Company applies ASC 718, Compensation—Stock Compensation (“ASC 718”), to account for its employee share-based payments. In accordance with ASC 718, the Company determines whether an award should be classified and accounted for as a liability award or equity award. All the Company’s grants of share-based awards to employees were classified as equity awards and are recognized in the financial statements based on their grant date fair values. Specifically, the grant date fair value of share options is calculated using an option pricing model. The fair value of restricted shares and restricted share units are based on the closing market price of our ADSs on the NASDAQ Global Select Market on the date of grant. The Company has elected to recognize compensation expense using the straight-line method for all employee equity awards granted with graded vesting based on service conditions provided that the amount of compensation cost recognized at any date is at least equal to the portion of the grant-date value of the options that are vested at that date. The Company uses the accelerated method for all awards granted with graded vesting based on performance conditions. To the extent the required vesting conditions are not met resulting in the forfeiture of the share-based awards, previously recognized compensation expense relating to those awards are reversed. ASC 718 requires forfeitures to be estimated at the time of grant and revised, if necessary, in the subsequent period if actual forfeitures differ from initial estimates. Forfeiture rates are estimated based on historical and future expectations of employee turnover rates and are adjusted to reflect future changes in circumstances and facts, if any. Share-based compensation expense is recorded net of estimated forfeitures such that expense is recorded only for those share-based awards that are expected to vest. To the extent the Company revises these estimates in the future, the share-based payments could be materially impacted in the period of revision, as well as in following periods. The Company, with the assistance of an independent third-party valuation firm, determined the estimated fair value of the stock options granted to employees using the binomial option pricing model. Awards granted to non-employees The Company has accounted for equity instruments issued to non-employees in accordance with the provisions of ASC 718 and ASC 505, Equity. All transactions in which goods or services are received in exchange for equity instruments are accounted for based on the fair value of the consideration received or the fair value of the equity instrument issued, whichever is more reliably measurable. The measurement date of the fair value of the equity instrument issued is the date on which the counterparty’s performance is completed as there is no associated performance commitment. The expense is recognized in the same manner as if the Company had paid cash for the services provided by the non-employees in accordance with ASC 505-50, Equity-based payments to non-employees. The Company estimated the fair value of share options granted to non-employees using the same method as employees. Modification of awards A change in any of the terms or conditions of the awards is accounted for as a modification of the award. Incremental compensation cost is measured as the excess, if any, of the fair value of the modified award over the fair value of the original award immediately before its terms are modified, measured based on the fair value of the awards and other pertinent factors at the modification date. For vested awards, the Company recognizes incremental compensation cost in the period the modification occurs. For unvested awards, the Company recognizes over the remaining requisite service period, the sum of the incremental compensation cost and the remaining unrecognized compensation cost for the original award on the modification date. If the fair value of the modified award is lower than the fair value of the original award immediately before modification, the minimum compensation cost the Company recognizes is the cost of the original award. |
| Income Taxes | Income Taxes The Company uses the liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are determined based on the differences between the financial reporting and the tax bases of assets and liabilities and are measured using enacted tax rates that will be in effect when the differences are expected to reverse. A valuation allowance is provided when it is more likely than not that some portion or all of a deferred tax asset will not be realized. In accordance with Accounting Standards Update (“ASU”) 2015-17, all deferred income tax assets and liabilities are classified as non-current on the consolidated balance sheets. The Company evaluates its uncertain tax positions using the provisions of ASC 740, Income Taxes, which prescribes a recognition threshold that a tax position is required to meet before being recognized in the financial statements. The Company recognizes in the financial statements the benefit of a tax position which is “more likely than not” to be sustained under examination based solely on the technical merits of the position assuming a review by tax authorities having all relevant information. Tax positions that meet the recognition threshold are measured using a cumulative probability approach, at the largest amount of tax benefit that has a greater than fifty percent likelihood of being realized upon settlement. It is the Company’s policy to recognize interest and penalties related to unrecognized tax benefits, if any, as a component of income tax expense. |
| Loss Per Share | Loss Per Share Loss per share is calculated in accordance with ASC 260, Earnings per Share . Basic loss per ordinary share is computed by dividing net loss attributable to ordinary shareholders by the weighted average number of ordinary shares outstanding during the period using the two-class method. Under the two-class method, net income is allocated between ordinary shares and participating securities based on dividends declared (or accumulated) and participating rights in undistributed earnings as if all the earnings for the reporting period had been distributed. The Company’s restricted shares are participating securities because they have contractual rights to share in the profits of the Company. However, the restricted shares do not have contractual rights and obligations to share in the losses of the Company. For the periods presented herein, the computation of basic loss per share using the two-class method is not applicable as the Company is in a net loss position. Diluted loss per share is calculated by dividing net loss attributable to ordinary shareholders as adjusted for the effect of dilutive ordinary equivalent shares, if any, by the weighted average number of ordinary and dilutive ordinary equivalent shares outstanding during the period. Ordinary equivalent shares consist of the ordinary shares issuable upon the conversion of the Company’s convertible preferred shares using the if-converted method, and ordinary shares issuable upon the conversion of the share options and unvested restricted shares, using the treasury stock method. Ordinary share equivalents are excluded from the computation of diluted loss per share if their effects would be anti-dilutive. Basic and diluted loss per ordinary share is presented in the Company’s consolidated statements of operations. |
| Segment Information | Segment Information In accordance with ASC 280, Segment Reporting, the Company’s chief operating decision maker, the Chief Executive Officer, reviews the consolidated results when making decisions about allocating resources and assessing performance of the Company as a whole and hence, the Company has only one reportable segment. The Company does not distinguish between markets or segments for the purpose of internal reporting. |
| Concentration of Risks | Concentration of Risks Concentration of credit risk Financial instruments that are potentially subject to credit risk consist of cash and cash equivalents and short-term investments. The carrying amounts of cash and cash equivalents and short-term investments represent the maximum amount of loss due to credit risk. As of December 31, 2018 and 2017 , $712,937 and $239,602 were deposited with various major reputable financial institutions located in the PRC and international financial institutions outside of the PRC. The deposits placed with financial institutions are not protected by statutory or commercial insurance. In the event of bankruptcy of one of these financial institutions, the Company may be unlikely to claim its deposits back in full. Management believes that these financial institutions are of high credit quality and continually monitors the credit worthiness of these financial institutions. As of December 31, 2018 and 2017 , the Company had short-term investments amounting to $1,068,509 and $597,914 , respectively. At December 31, 2018 , the Company’s short-term investments were comprised of U.S. treasury securities. The Company believes that U.S. treasury securities are of high credit quality and continually monitor the credit worthiness of these institutions. Customer concentration risk For the years ended December 31, 2018 and 2017, substantially all of the Company's revenue was from Celgene and our product distributor in China. For the year ended 2016 , substantially all of the Company’s revenue was generated solely from one customer, Merck KGaA, Darmstadt Germany. Business, customer, political, social and economic risks The Company participates in a dynamic biopharmaceutical industry and believes that changes in any of the following areas could have a material adverse effect on the Company’s future financial position, results of operations or cash flows: changes in the overall demand for services and products; competitive pressures due to new entrants; advances and new trends in new drugs and industry standards; changes in clinical research organizations, contract manufacturers and other key vendors; changes in certain strategic relationships or customer relationships; regulatory considerations; intellectual property considerations; and risks associated with the Company’s ability to attract and retain employees necessary to support its growth. The Company’s operations could be also adversely affected by significant political, economic and social uncertainties in the PRC. Currency convertibility risk A significant portion of the Company’s expenses, assets and liabilities are denominated in RMB. On January 1, 1994, the PRC government abolished the dual rate system and introduced a single rate of exchange as quoted daily by the People’s Bank of China (the “PBOC”). However, the unification of the exchange rates does not imply that the RMB may be readily convertible into U.S. dollar or other foreign currencies. All foreign exchange transactions continue to take place either through the PBOC or other banks authorized to buy and sell foreign currencies at the exchange rates quoted by the PBOC. Approvals of foreign currency payments by the PBOC or other institutions require submitting a payment application form together with suppliers’ invoices, shipping documents and signed contracts. Additionally, the value of the RMB is subject to changes in central government policies and international economic and political developments affecting supply and demand in the PRC foreign exchange trading system market. Foreign currency exchange rate risk From July 21, 2005, the RMB is permitted to fluctuate within a narrow and managed band against a basket of certain foreign currencies. For RMB against U.S. dollar, there was depreciation of approximately 5.7% , appreciation of approximately 6.5% and depreciation of approximately 6.3% , in the years ended December 31, 2018 , 2017 and 2016 . It is difficult to predict how market forces or PRC or U.S. government policy may impact the exchange rate between the RMB and the U.S. dollar in the future. To the extent that the Company needs to convert U.S. dollar into RMB for capital expenditures and working capital and other business purposes, appreciation of RMB against U.S. dollar would have an adverse effect on the RMB amount the Company would receive from the conversion. Conversely, if the Company decides to convert RMB into U.S. dollar for the purpose of making payments for dividends on ordinary shares, strategic acquisitions or investments or other business purposes, appreciation of U.S. dollar against RMB would have a negative effect on the U.S. dollar amount available to the Company. In addition, a significant depreciation of the RMB against the U.S. dollar may significantly reduce the U.S. dollar equivalent of the Company’s earnings or losses. |
| Recent Accounting Pronouncements | Recent Accounting Pronouncements New accounting standards which have been adopted In May 2014, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2014-9, Revenue from Contracts with Customers (Topic 606), or ASU 2014-9. Subsequently, the FASB issued ASU 2015-14, Revenue from Contracts with Customers (Topic 606), which adjusted the effective date of ASU 2014-9; ASU No. 2016-8, Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net), which amends the principal-versus-agent implementation guidance and illustrations in ASU 2014-9; ASU No. 2016-10, Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing, which clarifies identifying performance obligations and licensing implementation guidance and illustrations in ASU 2014-9; ASU No. 2016-12, Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients, which addresses implementation issues and is intended to reduce the cost and complexity of applying the new revenue standard in ASU 2014-9; ASU No. 2017-13, Revenue Recognition (Topic 605), Revenue from Contracts with Customers (Topic 606), Leases (Topic 840), and Leases (Topic 842): Amendments to SEC Paragraphs Pursuant to the Staff Announcement at the July 20, 2017 EITF Meeting and Rescission of Prior SEC Staff Announcements and Observer Comments (SEC Update) , which codifies recent announcements by the Securities and Exchange Commission, or SEC, staff; and ASU No. 2017-14, Income Statement—Reporting Comprehensive Income (Topic 220), Revenue Recognition (Topic 605), and Revenue from Contracts with Customers (Topic 606) (SEC Update) , which adds ASC 606-10-S25-1 as a result of SEC Release 33-10403, or collectively, the Revenue ASUs. The Revenue ASUs provide an accounting standard for a single comprehensive model for use in accounting for revenue arising from contracts with customers, and supersedes most current revenue recognition guidance. The accounting standard is effective for interim and annual periods beginning after December 15, 2017, with an option to early adopt for interim and annual periods beginning after December 15, 2016. The guidance permits two methods of adoption: retrospectively to each prior reporting period presented (the full retrospective method), or retrospectively with the cumulative effect of initially applying the guidance recognized at the date of initial application (the modified retrospective method). On January 1, 2018, the Company adopted the new standard using the modified retrospective method. The impact to the Company on adoption of the Revenue ASUs relates to variable consideration related to its collaboration agreement with Celgene Corporation ("Celgene") and the anticipated opt-in to certain clinical trials that are to be run by the Company, and funded by Celgene. Under Topic 605, even though the Company believed it was probable that the performance obligation related to the variable consideration would be satisfied as of December 31, 2017, the variable consideration was not realizable because formal notice had not been received. Upon its adoption of the Revenue ASUs, the Company determined it was probable that Celgene would opt-in to the clinical trials as of December 31, 2017 such that the variable consideration was not constrained, and therefore, the related revenue would have been recognized. In March 2018, the Company obtained formal notice of opt-in by Celgene. The Company recognized the cumulative effect of initially applying the new revenue standard as an adjustment to the opening balance of retained earnings. The comparative information has not been restated and continues to be reported under the accounting standards in effect for those periods. The cumulative effect of the changes made to the Company's consolidated January 1, 2018 balance sheet for the adoption of ASU 2014-9 resulted in an increase of $ 16,307 to both unbilled receivables and the opening balance of accumulated deficit. Please refer to the “Adoption of New Accounting Standards” section below for a tabular presentation of the impact. In October 2016, the FASB issued ASU No. 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory , which requires the recognition of the income tax consequences of an intra-entity transfer of an asset, other than inventory, when the transfer occurs. The Company adopted ASU 2016-16 during the first quarter of 2018 using the modified retrospective adoption method. In 2017, BeiGene HK's contribution of BeiGene Shanghai to BeiGene Biologics (and subsequent receipt of a related government grant) resulted in tax expenses $28,588 , which were reflected as other non-current assets in the Company’s December 31, 2017 balance sheet. The related government subsidy of $ 9,990 , which was received in 2017, was reflected as other long-term liabilities in the Company’s December 31, 2017 balance sheet. The adoption of this accounting standard resulted in an adjustment to beginning accumulated deficit for both of these items. In addition, the Company has now established a deferred tax asset resulting from a previous transfer of intellectual property to one of its wholly-owned subsidiaries. This deferred tax asset is entirely offset by a corresponding valuation allowance and therefore did not result in a change to beginning accumulated deficit. Please refer to the “Adoption of New Accounting Standards” section below for a tabular presentation of the impact. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows: Restricted Cash , which requires entities to present the aggregate changes in cash, cash equivalents, restricted cash and restricted cash equivalents in the statement of cash flows. As a result, the statement of cash flows will be required to present restricted cash and restricted cash equivalents as a part of the beginning and ending balances of cash and cash equivalents. The updated guidance became effective on January 1, 2018, and resulted in the presentation of restricted cash of $ 27,776 within the ending cash, cash equivalents, and restricted cash balance on the Company’s consolidated statement of cash flows. In May 2017, the FASB issued ASU No. 2017-9, Compensation – Stock Compensation: Scope of Modification Accounting . This standard provides clarity and reduces both (1) diversity in practice and (2) cost and complexity when applying the guidance in Topic 718, Compensation-Stock Compensation, to a change to the terms or conditions of a share-based payment award. The updated guidance became effective on January 1, 2018, and there was no material impact to the Company’s consolidated financial statements. In June 2018, the FASB issued ASU 2018-7, Compensation—Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting. This update expands the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from nonemployees. This update also specifies that Topic 718 applies to all share-based payment transactions in which a grantor acquires goods or services to be used or consumed in a grantor’s own operations by issuing share-based payment awards. This update is effective in fiscal years, including interim periods, beginning after December 15, 2018. Early adoption is permitted, but no earlier than an entity’s adoption date of Topic 606. The Company elected to early adopt this ASU during the quarter ended September 30, 2018, and there was no material impact to the Company's consolidated financial statements. Impact of adopted accounting standards The cumulative effect of changes made to the Company’s consolidated January 1, 2018 balance sheet for the adoption of the revenue ASUs and ASU 2016-16 were as follows: Balance at Adjustments Adjustments Balance at December 31, Due to Due to January 1, 2017 Revenue ASUs ASU 2016-16 2018 $ $ $ $ Assets: Unbilled receivable — 16,307 — 16,307 Other non-current assets 42,915 — (28,588 ) 14,327 Liabilities: Other long-term liabilities 31,959 — (9,990 ) 21,969 Equity: Accumulated other comprehensive loss (480 ) — 263 (217 ) Accumulated deficit (330,517 ) 16,307 (19,236 ) (333,446 ) Noncontrolling interest 14,422 — 375 14,797 New accounting standards which have not yet been adopted In February 2016, the FASB issued ASU No. 2016-2, Leases . Subsequently, the FASB issued ASU 2018-1, Land Easement Practical Expedient, which provides an optional transition practical expedient for land easements, ASU 2018-10, Codification Improvements to Topic 842, Leases , which clarifies certain aspects of the guidance issued in ASU 2016-2; ASU 2018-11, Leases (Topic 842): Targeted Improvements , which provides an additional transition method and a practical expedient for separating components of a contract for lessors, and ASU 2018-20, Leases (Topic 842)- Narrow-Scope Improvements for Lessors , which allows certain accounting policy elections for lessors (collectively, the "Lease ASUs"). The Lease ASUs require lessees to recognize assets and liabilities related to lease arrangements longer than 12 months on the balance sheet. This standard also requires additional disclosures by lessees and contains targeted changes to accounting by lessors. The updated guidance is effective for interim and annual periods beginning after December 15, 2018, and early adoption is permitted. Leases will be classified as finance or operating, with the classification affecting the pattern and classification of expense recognition. The recognition, measurement, and presentation of expenses and cash flows arising from a lease by a lessee have not significantly changed from previous GAAP. A modified retrospective transition approach is required, applying the new standard to all leases existing at the date of initial adoption. The guidance permits entities to choose to use either its effective date or the beginning of the earliest period presented in the financial statements as its date of initial application. The Company will adopt the new standard effective January 1, 2019 using the effective date method and will not restate comparative periods. The Company will elect the package of practical expedients permitted under the transition guidance within the new standard, which permits the Company not to reassess under the new standard its prior conclusions about lease identification, lease classification and initial direct costs. On adoption, we currently expect to recognize additional operating liabilities ranging from $ 25,000 to $ 30,000 , with corresponding right-of-use (ROU) assets of the same amount based on the present value of the remaining minimum rental payments under existing operating leases. Additionally, the Company expects to reclassify its land use rights of $ 45,058 to ROU assets upon adoption. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses ("ASU 2016-13"). The amendments in ASU 2016-13 update guidance on reporting credit losses for financial assets. These amendments affect loans, debt securities, trade receivables, net investments in leases, off balance sheet credit exposures, reinsurance receivables, and any other financial assets not excluded from the scope that have the contractual right to receive cash. For public business entities that are U.S. SEC filers, ASU 2016-13 is effective for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years. The Company is currently evaluating the impact on its financial statements of adopting this guidance. In February 2018, the FASB issued ASU 2018-2, Income Statement—Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income . This update allows companies the option to reclassify to retained earnings the tax effects related to items in accumulated other comprehensive income (loss) as a result of the Tax Cuts and Jobs Act that was enacted in the United States on December 22, 2017. This update is effective in fiscal years, including interim periods, beginning after December 15, 2018, and early adoption is permitted. This guidance should be applied either in the period of adoption or retrospectively to each period in which the effects of the change in the U.S. federal income tax rate in the Tax Cuts and Jobs Act is recognized. The Company does not expect this guidance to have a material impact on the Company’s consolidated financial statements. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework- Changes to the Disclosure Requirements for Fair Value Measurement . The update eliminates, modifies, and adds certain disclosure requirements for fair value measurements. This update is effective in fiscal years, including interim periods, beginning after December 15, 2019, and early adoption is permitted. The added disclosure requirements and the modified disclosure on the narrative description of measurement uncertainty should be applied prospectively for only the most recent interim or annual period presented. All other changes to disclosure requirements in this update should be applied retrospectively to all periods presented upon their effective date. The Company is currently evaluating the impact on its financial statements of adopting this guidance. In August 2018, the FASB issued ASU 2018-15, Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract . This update requires a customer in a cloud computing arrangement that is a service contract to follow the internal-use software guidance in ASC 350-40 to determine which implementation costs to defer and recognize as an asset. This update is effective in fiscal years, including interim periods, beginning after December 15, 2019, and early adoption is permitted. This guidance should be applied either retrospectively or prospectively to all implementation costs incurred after the date of adoption. The Company is currently evaluating the impact on its financial statements of adopting this guidance. In November 2018, the FASB issued ASU 2018-18, Collaborative Arrangements (Topic 808): Clarifying the Interaction between Topic 808 and Topic 606 . This update clarifies that certain transactions between participants in a collaborative arrangement should be accounted for under ASC 606 when the counterparty is a customer and precludes an entity from presenting consideration from a transaction in a collaborative arrangement as revenue from contracts with customers if the counterparty is not a customer for that transaction. The update is effective in fiscal years beginning after December 15, 2019, and interim periods therein, and early adoption is permitted for entities that have adopted ASC 606. This guidance should be applied retrospectively to the date of initial application of Topic 606. The Company is currently evaluating the impact on its financial statements of adopting this guidance. |
