Collaboration and License Agreement	3 Months Ended
Mar. 31, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
COLLABORATION AND LICENSE AGREEMENT	10. COLLABORATION AND LICENSE AGREEMENT Termination of the Novartis Collaboration Agreement In November 2017, the Company entered into a collaboration and license agreement with Novartis (as amended, the “Collaboration Agreement”) for the research, development, manufacturing and commercialization of products using the Company’s gene editing technology for the treatment of certain ophthalmic targets and sickle cell disease. In February 2019, Novartis elected to discontinue the sickle cell disease program under the Collaboration Agreement effective in August 2019. Under the terms of the Collaboration Agreement, the Company granted Novartis a research license, a development and commercialization license and a manufacturing license, under certain of its intellectual property rights to research, develop, manufacture and commercialize ophthalmic targets. The Collaboration Agreement included a research term, during which the Company and Novartis were collaborating to perform research and preclinical development work, as well development and commercialization terms, during which the Company would be responsible for manufacturing all product candidates and products. The Company and Novartis were also participating on a joint steering committee and a joint manufacturing subcommittee. The Company had determined that the (1) research, development and commercialization and manufacturing licenses, (2) the research activities performed by the Company, (3) service on the joint committees and (4) manufacturing during the research and development terms represented a single performance obligation under the Collaboration Agreement. On February 26, 2021, Homology received notice from Novartis that they had elected to terminate the Collaboration Agreement with the Company with respect to the remaining ophthalmic target under the Collaboration Agreement and as a result, the Company regained worldwide exclusive rights to this target. Accordingly, the notice served as notice of Novartis’ termination of the Collaboration Agreement in its entirety, which will be effective on August 26, 2021. Under the terms of the Collaboration Agreement, Novartis is obligated to continue to reimburse the Company for certain research and development costs through August 26, 2021. Upon effectiveness of the termination, such reimbursements will cease. The delivery of the termination notice caused a change in the estimate of total costs to satisfy the single performance obligation under the Collaboration Agreement. The cumulative effect of revisions to the total estimated costs to complete the Company’s single performance obligation was recorded in the current period when the changes were identified and amounts could be reasonably estimated. As such, the Company recognized a cumulative effect adjustment of approximately $26.9 million in collaboration revenue in the period. Revenue Recognition The Company recognizes revenue pursuant to the Collaboration Agreement over time using a cost-to-cost method, which it believes best depicts the transfer of control to the customer. Under the cost-to-cost method, the extent of progress towards completion is measured based on the ratio of actual costs incurred to the total estimated costs expected upon satisfying the identified performance obligation. Under this method, revenue is recorded over the performance period as a percentage of the estimated transaction price based on the extent of progress towards completion. As of March 31, 2021, the aggregate amount of the transaction price related to the unsatisfied portion of the performance obligation is $2.0 million, and the Company will recognize this revenue as the remaining research activities are performed, which will conclude on August 26, 2021. During the three months ended March 31, 2021 and 2020, the Company recognized revenue under the Collaboration Agreement of $28.5 million and $0.6 million, respectively, of which $28.2 million and $0.2 million was included in deferred revenue at the beginning of each such period. As of March 31, 2021 and December 31, 2020, there was approximately $2.0 million and $30.2 million of deferred revenue related to the Collaboration Agreement, respectively. In addition, as of March 31, 2021 and December 31, 2020, the Company has recorded accounts receivable of $0.3 million and $0.4 million, respectively, related to reimbursable research and development costs under the Collaboration Agreement, which are included in prepaid expenses and other current assets on the condensed consolidated balance sheets as of each such date.

Collaboration and License Agreement

3 Months Ended

Mar. 31, 2021

Organization Consolidation And Presentation Of Financial Statements [Abstract]

10. COLLABORATION AND LICENSE AGREEMENT

Termination of the Novartis Collaboration Agreement

In November 2017, the Company entered into a collaboration and license agreement with Novartis (as amended, the “Collaboration Agreement”) for the research, development, manufacturing and commercialization of products using the Company’s gene editing technology for the treatment of certain ophthalmic targets and sickle cell disease. In February 2019, Novartis elected to discontinue the sickle cell disease program under the Collaboration Agreement effective in August 2019. Under the terms of the Collaboration Agreement, the Company granted Novartis a research license, a development and commercialization license and a manufacturing license, under certain of its intellectual property rights to research, develop, manufacture and commercialize ophthalmic targets. The Collaboration Agreement included a research term, during which the Company and Novartis were collaborating to perform research and preclinical development work, as well development and commercialization terms, during which the Company would be responsible for manufacturing all product candidates and products. The Company and Novartis were also participating on a joint steering committee and a joint manufacturing subcommittee. The Company had determined that the (1) research, development and commercialization and manufacturing licenses, (2) the research activities performed by the Company, (3) service on the joint committees and (4) manufacturing during the research and development terms represented a single performance obligation under the Collaboration Agreement.

On February 26, 2021, Homology received notice from Novartis that they had elected to terminate the Collaboration Agreement with the Company with respect to the remaining ophthalmic target under the Collaboration Agreement and as a result, the Company regained worldwide exclusive rights to this target. Accordingly, the notice served as notice of Novartis’ termination of the Collaboration Agreement in its entirety, which will be effective on August 26, 2021. Under the terms of the Collaboration Agreement, Novartis is obligated to continue to reimburse the Company for certain research and development costs through August 26, 2021. Upon effectiveness of the termination, such reimbursements will cease.

The delivery of the termination notice caused a change in the estimate of total costs to satisfy the single performance obligation under the Collaboration Agreement. The cumulative effect of revisions to the total estimated costs to complete the Company’s single performance obligation was recorded in the current period when the changes were identified and amounts could be reasonably estimated. As such, the Company recognized a cumulative effect adjustment of approximately $26.9 million in collaboration revenue in the period.

Revenue Recognition

The Company recognizes revenue pursuant to the Collaboration Agreement over time using a cost-to-cost method, which it believes best depicts the transfer of control to the customer. Under the cost-to-cost method, the extent of progress towards completion is measured based on the ratio of actual costs incurred to the total estimated costs expected upon satisfying the identified performance obligation. Under this method, revenue is recorded over the performance period as a percentage of the estimated transaction price based on the extent of progress towards completion. As of March 31, 2021, the aggregate amount of the transaction price related to the unsatisfied portion of the performance obligation is $2.0 million, and the Company will recognize this revenue as the remaining research activities are performed, which will conclude on August 26, 2021.

During the three months ended March 31, 2021 and 2020, the Company recognized revenue under the Collaboration Agreement of $28.5 million and $0.6 million, respectively, of which $28.2 million and $0.2 million was included in deferred revenue at the beginning of each such period. As of March 31, 2021 and December 31, 2020, there was approximately $2.0 million and $30.2 million of deferred revenue related to the Collaboration Agreement, respectively. In addition, as of March 31, 2021 and December 31, 2020, the Company has recorded accounts receivable of $0.3 million and $0.4 million, respectively, related to reimbursable research and development costs under the Collaboration Agreement, which are included in prepaid expenses and other current assets on the condensed consolidated balance sheets as of each such date.