Summary of significant accounting policies	9 Months Ended
Sep. 30, 2019
Summary of significant accounting policies
Summary of significant accounting policies	2. Summary of significant accounting policies The Company’s significant accounting policies are disclosed in the audited consolidated financial statements for the year ended December 31, 2018 included in the Company’s final prospectus for the IPO filed pursuant to Rule 424(b) under the Securities Act, with the Securities and Exchange Commission (“SEC”), on May 23, 2019. Since the date of such consolidated financial statements, there have been no changes to the Company’s significant accounting policies, other than those disclosed below. Unaudited Interim Financial Information Certain information in the footnote disclosures of the financial statements has been condensed or omitted pursuant to the rules and regulations of the SEC. These unaudited condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and notes thereto for the year ended December 31, 2018 included in the Company’s final prospectus for the IPO filed pursuant to Rule 424(b) under the Securities Act, with the SEC, on May 23, 2019. The accompanying condensed consolidated balance sheet at September 30, 2019, condensed consolidated statements of operations and comprehensive loss, condensed consolidated statements of convertible preferred shares and shareholders’ equity (deficit) for the three and nine months ended September 30, 2019 and 2018, and the condensed consolidated statements of cash flows for the nine months ended September 30, 2019 and 2018 and the related financial information disclosed in these notes are unaudited. The unaudited interim financial statements have been prepared on the same basis as the audited annual financial statements for the year ended December 31, 2018, and, in the opinion of management, reflect all adjustments, consisting of normal recurring adjustments, necessary for the fair presentation of the Company’s financial position as of September 30, 2019, the results of its operations for the three and nine months ended September 30, 2019 and 2018, and its cash flows for the nine months ended September 30, 2019 and 2018. The results for the three and nine months ended September 30, 2019 are not necessarily indicative of the results to be expected for the year ending December 31, 2019, any other interim periods, or any future year or period. Foreign currency and currency translation The functional currency is the currency of the primary economic environment in which an entity’s operations are conducted. On June 1, 2019, Bicycle Therapeutics plc adopted the U.S. dollar as its functional currency. Bicycle Therapeutics plc is a holding company that has no operating activities and its primary functions are to serve as a financing vehicle to fund the operations of the Company’s operating entities, to serve as the listing company needed to access U.S. capital markets, and to hold investments. Therefore, its financing source is the primary indicator of its cash flows and its functional currency. The change in functional currency from the British Pound Sterling is due to a change in the source of Bicycle Therapeutics plc’s financing and cash flows, which following the completion of the IPO is now primarily the U.S. dollar. Historically its financing had been in British Pound Sterling. The functional currency of Bicycle Therapeutics plc’s wholly owned non-U.S. subsidiaries, BicycleTx Limited and BicycleRD Limited, is the British Pound Sterling and the functional currency of its U.S. subsidiary, Bicycle Therapeutics Inc. is the U.S. Dollar (“USD”). The functional currency of the Company’s subsidiaries is the same as the local currency. Monetary assets and liabilities denominated in currencies other than the functional currency are remeasured into the functional currency at rates of exchange prevailing at the balance sheet dates. Non-monetary assets and liabilities denominated in foreign currencies are remeasured into the functional currency at the exchange rates prevailing at the date of the transaction. Exchange gains or losses arising from foreign currency transactions are included in the determination of net loss for the respective periods. Adjustments that arise from exchange rate changes on transactions denominated in a currency other than the local currency are included in general and administrative expense in the condensed consolidated statements of operations and comprehensive loss as incurred. The Company recorded a foreign exchange loss of $0.8 million and an exchange gain of $41,000 during the three months ended September 30, 2019 and 2018, respectively, and a foreign exchange loss of $0.4 million and an exchange gain of $0.4 million for the nine months ended September 30, 2019 and 2018, respectively. The Company translates the assets and liabilities of BicycleTx Limited and BicycleRD Limited into USD at the exchange rate in effect on the balance sheet date. Revenues and expenses are translated at the average exchange rate in effect during the period. Unrealized translation gains and losses are recorded as a foreign currency translation adjustment, which is included in the condensed consolidated statements of convertible preferred shares and shareholders’ equity (deficit) as a component of accumulated other comprehensive income (loss). Leases The Company determines if an arrangement is a lease at inception. Operating leases are included in operating lease right‑of‑use (“ROU”) assets, other current liabilities, and operating lease liabilities in the Company’s condensed consolidated balance sheet. The Company has not entered into any financing leases. ROU assets represent the Company’s right to use and control an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. ROU assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. As the Company’s leases do not provide an implicit rate, the Company uses its incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. The ROU asset also includes lease payments made before the lease commencement date and excludes any lease incentives. The Company’s lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. The components of a lease shall be split into three categories, if applicable: lease components (e.g., land, building, etc.), non‑lease components (e.g., common area maintenance, maintenance, consumables, etc.), and non‑components (e.g., property taxes, insurance, etc.). The fixed and in‑substance fixed contract consideration (including any related to non‑components) must then be allocated based on fair values to the lease components and non‑lease components. The Company’s facilities operating leases may have lease and non‑lease components to which the Company has elected to apply a practical expedient to account for each lease component and related non‑lease component as one single component. The lease component results in a right‑of‑use asset being recorded on the balance sheet. Lease expense for lease payments is recognized on a straight‑line basis over the lease term. Government grants From time to time, the Company may enter into arrangements with governmental entities for the purposes of obtaining funding for research and development activities. The Company recognizes government grant funding in the condensed consolidated statements of operations and comprehensive loss as the related expenses being funded are incurred. The Company classifies government grants received under these arrangements as a reduction to the related research and development expense incurred. The Company analyzes each arrangement on a case‑by‑case basis. For the three and nine months ended September 30, 2019, the Company recognized $0.2 and $0.5 million, respectively, as a reduction of research and development expense related to government grant arrangements. There were no grant proceeds recognized for the three and nine month periods ended September 30, 2018. Recently adopted accounting pronouncements In February 2016, the FASB issued ASU No. 2016‑02, Leases (Topic 842) (“ASU 2016‑02”). This guidance revises existing practice related to accounting for leases under ASC Topic 840 Leases (“ASC 840”). ASU 2016‑02 requires lessees to recognize most leases on their balance sheet as a right‑of‑use asset and a lease liability. The lease liability is equal to the present value of lease payments and the right‑of‑use asset is based on the lease liability, subject to adjustment such as for initial direct costs. For income statement purposes, the new standard retains a dual model similar to ASC 840, requiring leases to be classified as either operating or finance. For lessees, operating leases will result in straight‑line expense (similar to current accounting by lessees for operating leases under ASC 840). In July 2018, the FASB issued ASU No. 2018‑11, Leases (Topic 842) Targeted Improvements, which provides an additional transition method that allows entities to initially apply the new standard at the adoption date and recognize a cumulative‑effect adjustment to the opening balance of retained earnings in the period of adoption without restating prior periods. The guidance is effective for annual reporting periods beginning after December 15, 2018 and interim periods within those fiscal years, and early adoption is permitted. The Company adopted the new standard on January 1, 2019 by applying the new lease requirements at the adoption date without restating prior periods. In connection with the adoption of ASU 2016‑02 the Company recorded an impact of approximately $2.7 million on its condensed consolidated balance sheet to record right‑of‑use‑assets and $2.6 million to record lease liabilities on January 1, 2019, which are primarily related to the lease of the Company’s corporate headquarters in the U.K. and the lease of its office and laboratory space in Lexington, Massachusetts. The adoption of ASU 2016‑02 did not have a material impact on the Company’s results of operations or cash flows. In June 2018, the FASB issued ASU No. 2018‑07, Compensation — Stock Compensation: Improvements to Nonemployee Share‑Based Payment Accounting (“ASU 2018‑07”) to simplify the accounting for share‑based payments to non‑employees by aligning it with the accounting for share‑based payments to employees, with certain exceptions. The new guidance expands the scope of ASC 718, Compensation — Stock Compensation, to include share‑based payments granted to non‑employees in exchange for goods or services used or consumed in an entity’s own operations and supersedes the guidance in ASC Topic 505‑50, Equity‑Based Payments to Non‑Employees. The guidance is effective for public business entities in annual periods beginning after December 15, 2018 and interim periods within those years. Early adoption is permitted. The Company adopted the new standard on January 1, 2019. The adoption did not have a material impact on the Company’s financial position, results of operations or cash flows. In August 2018, the FASB issued ASU No. 2018‑15, Intangibles (Topic 350): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract, which aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. This standard also requires customers to amortize the capitalized implementation costs of a hosting arrangement that is a service contract over the term of the hosting arrangement. The Company early adopted this standard, as of April 1, 2019, on a prospective basis for applicable implementation costs. The adoption of this standard would not have had a material impact to historical accounting periods, but will impact implementation costs that are incurred for the remainder of 2019 and in future periods. In June 2016, the FASB issued ASU No. 2016-13, Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”). ASU 2016-13 will change how companies account for credit losses for most financial assets and certain other instruments. For trade receivables, loans and held-to-maturity debt securities, companies will be required to recognize an allowance for credit losses rather than reducing the carrying value of the asset. ASU 2016-13 is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted. The Company is currently evaluating the potential impact that the adoption of ASU 2016-13 will have on the Company’s financial position and results of operations.

2. Summary of significant accounting policies

The Company’s significant accounting policies are disclosed in the audited consolidated financial statements for the year ended December 31, 2018 included in the Company’s final prospectus for the IPO filed pursuant to Rule 424(b) under the Securities Act, with the Securities and Exchange Commission (“SEC”), on May 23, 2019. Since the date of such consolidated financial statements, there have been no changes to the Company’s significant accounting policies, other than those disclosed below.

Unaudited Interim Financial Information

Certain information in the footnote disclosures of the financial statements has been condensed or omitted pursuant to the rules and regulations of the SEC. These unaudited condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and notes thereto for the year ended December 31, 2018 included in the Company’s final prospectus for the IPO filed pursuant to Rule 424(b) under the Securities Act, with the SEC, on May 23, 2019.

The accompanying condensed consolidated balance sheet at September 30, 2019, condensed consolidated statements of operations and comprehensive loss, condensed consolidated statements of convertible preferred shares and shareholders’ equity (deficit) for the three and nine months ended September 30, 2019 and 2018, and the condensed consolidated statements of cash flows for the nine months ended September 30, 2019 and 2018 and the related financial information disclosed in these notes are unaudited. The unaudited interim financial statements have been prepared on the same basis as the audited annual financial statements for the year ended December 31, 2018, and, in the opinion of management, reflect all adjustments, consisting of normal recurring adjustments, necessary for the fair presentation of the Company’s financial position as of September 30, 2019, the results of its operations for the three and nine months ended September 30, 2019 and 2018, and its cash flows for the nine months ended September 30, 2019 and 2018. The results for the three and nine months ended September 30, 2019 are not necessarily indicative of the results to be expected for the year ending December 31, 2019, any other interim periods, or any future year or period.

Foreign currency and currency translation

The functional currency is the currency of the primary economic environment in which an entity’s operations are conducted. On June 1, 2019, Bicycle Therapeutics plc adopted the U.S. dollar as its functional currency. Bicycle Therapeutics plc is a holding company that has no operating activities and its primary functions are to serve as a financing vehicle to fund the operations of the Company’s operating entities, to serve as the listing company needed to access U.S. capital markets, and to hold investments. Therefore, its financing source is the primary indicator of its cash flows and its functional currency. The change in functional currency from the British Pound Sterling is due to a change in the source of Bicycle Therapeutics plc’s financing and cash flows, which following the completion of the IPO is now primarily the U.S. dollar. Historically its financing had been in British Pound Sterling.

The functional currency of Bicycle Therapeutics plc’s wholly owned non-U.S. subsidiaries, BicycleTx Limited and BicycleRD Limited, is the British Pound Sterling and the functional currency of its U.S. subsidiary, Bicycle Therapeutics Inc. is the U.S. Dollar (“USD”). The functional currency of the Company’s subsidiaries is the same as the local currency.

Monetary assets and liabilities denominated in currencies other than the functional currency are remeasured into the functional currency at rates of exchange prevailing at the balance sheet dates. Non-monetary assets and liabilities denominated in foreign currencies are remeasured into the functional currency at the exchange rates prevailing at the date of the transaction. Exchange gains or losses arising from foreign currency transactions are included in the determination of net loss for the respective periods. Adjustments that arise from exchange rate changes on transactions denominated in a currency other than the local currency are included in general and administrative expense in the condensed consolidated statements of operations and comprehensive loss as incurred. The Company recorded a foreign exchange loss of $0.8 million and an exchange gain of $41,000 during the three months ended September 30, 2019 and 2018, respectively, and a foreign exchange loss of $0.4 million and an exchange gain of $0.4 million for the nine months ended September 30, 2019 and 2018, respectively.

The Company translates the assets and liabilities of BicycleTx Limited and BicycleRD Limited into USD at the exchange rate in effect on the balance sheet date. Revenues and expenses are translated at the average exchange rate in effect during the period. Unrealized translation gains and losses are recorded as a foreign currency translation adjustment, which is included in the condensed consolidated statements of convertible preferred shares and shareholders’ equity (deficit) as a component of accumulated other comprehensive income (loss).

Leases

The Company determines if an arrangement is a lease at inception. Operating leases are included in operating lease right‑of‑use (“ROU”) assets, other current liabilities, and operating lease liabilities in the Company’s condensed consolidated balance sheet. The Company has not entered into any financing leases.

ROU assets represent the Company’s right to use and control an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. ROU assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. As the Company’s leases do not provide an implicit rate, the Company uses its incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. The ROU asset also includes lease payments made before the lease commencement date and excludes any lease incentives. The Company’s lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option.

The components of a lease shall be split into three categories, if applicable: lease components (e.g., land, building, etc.), non‑lease components (e.g., common area maintenance, maintenance, consumables, etc.), and non‑components (e.g., property taxes, insurance, etc.). The fixed and in‑substance fixed contract consideration (including any related to non‑components) must then be allocated based on fair values to the lease components and non‑lease components. The Company’s facilities operating leases may have lease and non‑lease components to which the Company has elected to apply a practical expedient to account for each lease component and related non‑lease component as one single component. The lease component results in a right‑of‑use asset being recorded on the balance sheet. Lease expense for lease payments is recognized on a straight‑line basis over the lease term.

Government grants

From time to time, the Company may enter into arrangements with governmental entities for the purposes of obtaining funding for research and development activities. The Company recognizes government grant funding in the condensed consolidated statements of operations and comprehensive loss as the related expenses being funded are incurred. The Company classifies government grants received under these arrangements as a reduction to the related research and development expense incurred. The Company analyzes each arrangement on a case‑by‑case basis. For the three and nine months ended September 30, 2019, the Company recognized $0.2 and $0.5 million, respectively, as a reduction of research and development expense related to government grant arrangements. There were no grant proceeds recognized for the three and nine month periods ended September 30, 2018.

Recently adopted accounting pronouncements

In February 2016, the FASB issued ASU No. 2016‑02, Leases (Topic 842) (“ASU 2016‑02”). This guidance revises existing practice related to accounting for leases under ASC Topic 840 Leases (“ASC 840”). ASU 2016‑02 requires lessees to recognize most leases on their balance sheet as a right‑of‑use asset and a lease liability. The lease liability is equal to the present value of lease payments and the right‑of‑use asset is based on the lease liability, subject to adjustment such as for initial direct costs. For income statement purposes, the new standard retains a dual model similar to ASC 840, requiring leases to be classified as either operating or finance. For lessees, operating leases will result in straight‑line expense (similar to current accounting by lessees for operating leases under ASC 840). In July 2018, the FASB issued ASU No. 2018‑11, Leases (Topic 842) Targeted Improvements, which provides an additional transition method that allows entities to initially apply the new standard at the adoption date and recognize a cumulative‑effect adjustment to the opening balance of retained earnings in the period of adoption without restating prior periods. The guidance is effective for annual reporting periods beginning after December 15, 2018 and interim periods within those fiscal years, and early adoption is permitted. The Company adopted the new standard on January 1, 2019 by applying the new lease requirements at the adoption date without restating prior periods. In connection with the adoption of ASU 2016‑02 the Company recorded an impact of approximately $2.7 million on its condensed consolidated balance sheet to record right‑of‑use‑assets and $2.6 million to record lease liabilities on January 1, 2019, which are primarily related to the lease of the Company’s corporate headquarters in the U.K. and the lease of its office and laboratory space in Lexington, Massachusetts. The adoption of ASU 2016‑02 did not have a material impact on the Company’s results of operations or cash flows.

In June 2018, the FASB issued ASU No. 2018‑07, Compensation — Stock Compensation: Improvements to Nonemployee Share‑Based Payment Accounting (“ASU 2018‑07”) to simplify the accounting for share‑based payments to non‑employees by aligning it with the accounting for share‑based payments to employees, with certain exceptions. The new guidance expands the scope of ASC 718, Compensation — Stock Compensation, to include share‑based payments granted to non‑employees in exchange for goods or services used or consumed in an entity’s own operations and supersedes the guidance in ASC Topic 505‑50, Equity‑Based Payments to Non‑Employees. The guidance is effective for public business entities in annual periods beginning after December 15, 2018 and interim periods within those years. Early adoption is permitted. The Company adopted the new standard on January 1, 2019. The adoption did not have a material impact on the Company’s financial position, results of operations or cash flows.

In August 2018, the FASB issued ASU No. 2018‑15, Intangibles (Topic 350): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract, which aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. This standard also requires customers to amortize the capitalized implementation costs of a hosting arrangement that is a service contract over the term of the hosting arrangement. The Company early adopted this standard, as of April 1, 2019, on a prospective basis for applicable implementation costs. The adoption of this standard would not have had a material impact to historical accounting periods, but will impact implementation costs that are incurred for the remainder of 2019 and in future periods.

In June 2016, the FASB issued ASU No. 2016-13, Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”). ASU 2016-13 will change how companies account for credit losses for most financial assets and certain other instruments. For trade receivables, loans and held-to-maturity debt securities, companies will be required to recognize an allowance for credit losses rather than reducing the carrying value of the asset. ASU 2016-13 is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted. The Company is currently evaluating the potential impact that the adoption of ASU 2016-13 will have on the Company’s financial position and results of operations.