LEASES	3 Months Ended
Mar. 31, 2020
Leases [Abstract]
LEASES	13. LEASES The Company has real estate operating leases in Cambridge, Andover and Burlington, Massachusetts and Dublin and Columbus, Ohio that provide for scheduled annual rent increases throughout each lease’s term. There have been no significant changes to the real estate leases in the three months ended March 31, 2020. The Company has also identified embedded leases in its manufacturing and supply agreements with Catalent, Inc. (“Catalent”) and Thermo Fisher Scientific, Inc. (“Thermo”). For additional details relating to these two agreements, please read Note 21, Commitments and Contingencies of the Annual Report on Form 10-K for the year ended December 31, 2019. Catalent, Inc. In October 2018 and February 2019, the Company entered into a manufacturing collaboration agreement and a manufacturing and supply agreement, respectively, (collectively, the “Catalent Agreements”) with Catalent, Inc., formerly Paragon Bioservices, Inc. (“Catalent”). Pursuant to the terms of the Catalent Agreements, Catalent agreed to provide the Company with two dedicated clean room suites and an option to gain access to two additional dedicated clean room suites for its gene therapy programs. In September 2019, the Company exercised the option to gain access to the two additional dedicated clean room suites. The Catalent Agreements will expire on December 31, 2024, unless the Company and Catalent mutually agree to extend the term. The Company has the ability to terminate the Catalent Agreements prior to expiration, subject to potential additional financial consideration. The Company concluded that the Catalent Agreements contain an embedded lease as the Company controls the use of the dedicated clean room suites and related equipment therein. The Company also determined that it did not control the facility or related equipment during construction and, thus, the lease did not fall in the scope of “build-to-suit” accounting. The lease on two of the four dedicated clean room suites commenced during the quarter ended March 31, 2020, which is when the dedicated clean room suites became available for use by the Company. Accordingly, the fixed and in-substance fixed contract consideration associated with the two dedicated clean room suites was allocated to the lease and non-lease components. The lease component was determined based on the estimated standalone price of the leased clean rooms and the associated equipment based on available market and specific cost information. The non-lease component was determined using the residual estimation approach as the standalone price of the gene therapy manufacturing and supply services provided by Catalent is highly variable. Consequently, as of March 31, 2020, the Company recorded a right of use (“ROU”) asset of $27.0 million and a lease liability of $24.3 million relating to these two dedicated clean room suites. The ROU asset and lease liability were based on the present value of estimated future payments associated with the lease component of the clean room suites at a discount rate of 8%, representing the rate at which the Company could borrow on a collateralized basis the amount of the lease payments in a similar term. The difference between the ROU asset and the lease liability results from certain prepayments made to Catalent by the Company prior to the commencement of the leases. The weighted average remaining lease term on the leases for the two dedicated clean room suites is approximately 4.8 years. During the first quarter of 2020, the Company recorded operating lease costs of $0.8 million and variable lease costs of $0.9 million, relating to these two dedicated clean room suits which was included in the research and development expense in the accompanying unaudited condensed consolidated statements of operations and comprehensive loss. The total lease liability payment is expected to be paid in equal installments through the five-year term of the agreement. The lease on the remaining two clean room suites has not commenced as of March 31, 2020 because the clean room suites at the Catalent facility are not yet available for use by the Company. Accordingly, cumulative payments totaling $18.0 million made to Catalent relating to the remaining two clean room suites have been recorded as an other asset in the accompanying consolidated balance sheets, a portion of which will be considered in the initial measurement of the cost of the ROU asset at the lease commencement date, currently anticipated to occur in the fourth quarter of 2020. Thermo Fisher Scientific, Inc. The Company entered into a development, commercial manufacturing and supply agreement and, subsequently, entered into the first amendment (collectively, the “Thermo Agreements”) with Thermo Fisher Scientific, Inc., formerly Brammer Bio MA, LLC (“Thermo”) in June 2018 and May 2019, respectively. Pursuant to the terms of the Thermo Agreements, Thermo agreed to provide the Company with access to clinical and commercial manufacturing capacity for its gene therapy programs. The Thermo Agreements will continue for a period of six years following the first regulatory approval of a product manufactured under the agreements. The Company has the ability to terminate the Thermo Agreements prior to expiration but would be required to continue remitting capacity access fees to Thermo for up to eight additional quarters. The Company determined that the Thermo Agreements contain an embedded lease because the Company controls the use of the facility and related equipment therein. The Company also determined that it does not control the facility or related equipment during construction and, thus, the lease does not fall in the scope of “build-to-suit” accounting. As of March 31, 2020, the embedded lease in the Thermo Agreements has not commenced as the clean room suites and related equipment therein at the Thermo facility have not been available for use by the Company. Accordingly, total cumulative payments made to Thermo of $86.3 million have been recorded as other assets in the accompanying unaudited condensed consolidated balance sheets and the lease portion of these prepayments will be considered in the initial measurement of the cost of the ROU asset at the lease commencement date, currently anticipated to occur in the second quarter of 2020.

LEASES

3 Months Ended

Mar. 31, 2020

13. LEASES

The Company has real estate operating leases in Cambridge, Andover and Burlington, Massachusetts and Dublin and Columbus, Ohio that provide for scheduled annual rent increases throughout each lease’s term. There have been no significant changes to the real estate leases in the three months ended March 31, 2020. The Company has also identified embedded leases in its manufacturing and supply agreements with Catalent, Inc. (“Catalent”) and Thermo Fisher Scientific, Inc. (“Thermo”). For additional details relating to these two agreements, please read Note 21, Commitments and Contingencies of the Annual Report on Form 10-K for the year ended December 31, 2019.

Catalent, Inc.

In October 2018 and February 2019, the Company entered into a manufacturing collaboration agreement and a manufacturing and supply agreement, respectively, (collectively, the “Catalent Agreements”) with Catalent, Inc., formerly Paragon Bioservices, Inc. (“Catalent”). Pursuant to the terms of the Catalent Agreements, Catalent agreed to provide the Company with two dedicated clean room suites and an option to gain access to two additional dedicated clean room suites for its gene therapy programs. In September 2019, the Company exercised the option to gain access to the two additional dedicated clean room suites. The Catalent Agreements will expire on December 31, 2024, unless the Company and Catalent mutually agree to extend the term. The Company has the ability to terminate the Catalent Agreements prior to expiration, subject to potential additional financial consideration.

The Company concluded that the Catalent Agreements contain an embedded lease as the Company controls the use of the dedicated clean room suites and related equipment therein. The Company also determined that it did not control the facility or related equipment during construction and, thus, the lease did not fall in the scope of “build-to-suit” accounting.

The lease on two of the four dedicated clean room suites commenced during the quarter ended March 31, 2020, which is when the dedicated clean room suites became available for use by the Company. Accordingly, the fixed and in-substance fixed contract consideration associated with the two dedicated clean room suites was allocated to the lease and non-lease components. The lease component was determined based on the estimated standalone price of the leased clean rooms and the associated equipment based on available market and specific cost information. The non-lease component was determined using the residual estimation approach as the standalone price of the gene therapy manufacturing and supply services provided by Catalent is highly variable. Consequently, as of March 31, 2020, the Company recorded a right of use (“ROU”) asset of $27.0 million and a lease liability of $24.3 million relating to these two dedicated clean room suites. The ROU asset and lease liability were based on the present value of estimated future payments associated with the lease component of the clean room suites at a discount rate of 8%, representing the rate at which the Company could borrow on a collateralized basis the amount of the lease payments in a similar term. The difference between the ROU asset and the lease liability results from certain prepayments made to Catalent by the Company prior to the commencement of the leases. The weighted average remaining lease term on the leases for the two dedicated clean room suites is approximately 4.8 years. During the first quarter of 2020, the Company recorded operating lease costs of $0.8 million and variable lease costs of $0.9 million, relating to these two dedicated clean room suits which was included in the research and development expense in the accompanying unaudited condensed consolidated statements of operations and comprehensive loss. The total lease liability payment is expected to be paid in equal installments through the five-year term of the agreement.

The lease on the remaining two clean room suites has not commenced as of March 31, 2020 because the clean room suites at the Catalent facility are not yet available for use by the Company. Accordingly, cumulative payments totaling $18.0 million made to Catalent relating to the remaining two clean room suites have been recorded as an other asset in the accompanying consolidated balance sheets, a portion of which will be considered in the initial measurement of the cost of the ROU asset at the lease commencement date, currently anticipated to occur in the fourth quarter of 2020.

Thermo Fisher Scientific, Inc.

The Company entered into a development, commercial manufacturing and supply agreement and, subsequently, entered into the first amendment (collectively, the “Thermo Agreements”) with Thermo Fisher Scientific, Inc., formerly Brammer Bio MA, LLC (“Thermo”) in June 2018 and May 2019, respectively. Pursuant to the terms of the Thermo Agreements, Thermo agreed to provide the Company with access to clinical and commercial manufacturing capacity for its gene therapy programs. The Thermo Agreements will continue for a period of six years following the first regulatory approval of a product manufactured under the agreements. The Company has the ability to terminate the Thermo Agreements prior to expiration but would be required to continue remitting capacity access fees to Thermo for up to eight additional quarters.

The Company determined that the Thermo Agreements contain an embedded lease because the Company controls the use of the facility and related equipment therein. The Company also determined that it does not control the facility or related equipment during construction and, thus, the lease does not fall in the scope of “build-to-suit” accounting. As of March 31, 2020, the embedded lease in the Thermo Agreements has not commenced as the clean room suites and related equipment therein at the Thermo facility have not been available for use by the Company. Accordingly, total cumulative payments made to Thermo of $86.3 million have been recorded as other assets in the accompanying unaudited condensed consolidated balance sheets and the lease portion of these

prepayments will be considered in the initial measurement of the cost of the ROU asset at the lease commencement date, currently anticipated to occur in the second quarter of 2020.