Collaboration and License Agreement	3 Months Ended
Mar. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
COLLABORATION AND LICENSE AGREEMENT	10. COLLABORATION AND LICENSE AGREEMENT Summary of Agreement In November 2017, the Company entered into a collaboration and license agreement (the “Collaboration Agreement”) with Novartis Institutes of BioMedical Research, Inc. (“Novartis”) 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. The Company continues to work with Novartis to identify new targets for the partnership based on the existing exploratory research component of the agreement, and the collaboration on ophthalmic programs also continues. Under the terms of the Collaboration Agreement, taking into account Novartis’ election to discontinue the sickle cell disease program, 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 the ophthalmic targets. Upon entering into the Collaboration Agreement, the Company received an upfront, nonrefundable payment of $35.0 million and issued additional shares of its Series B preferred stock to Novartis for consideration of $10.0 million. The Company recorded the Series B preferred stock at its estimated fair value of $11.7 million, including $1.7 million of the upfront payment, and allocated the remaining $33.3 million of the upfront payment to the Collaboration Agreement. The Collaboration Agreement consists of a research term, where the Company and Novartis are collaborating to perform research and conduct preclinical development to identify candidates that modulate the ophthalmic targets. The Collaboration Agreement also includes exploratory work on the applicability of the gene-editing technology with respect to other gene targets. The Company’s obligation to perform such exploratory research concludes in November 2020. Novartis may select up to two targets, with limited substitution rights. The Company is responsible for the manufacturing of proprietary research grade human hematopoietic stem cell derived adeno-associated virus vectors (“AAVHSCs”) during the research term. Research activities performed by the Company are being reimbursed at a full-time equivalent rate (“FTE”) and manufacturing activities will be reimbursed at cost, up to a maximum of $17.0 million during the research term, as specified and defined in the Collaboration Agreement. Novartis is required to pay the Company a target fee of $5.0 million for each target that meets certain success criteria during the research term (the “target fee trigger date”), up to a maximum of two targets. The research term will continue for five years from the effective date of the Collaboration Agreement. Pursuant to the Collaboration Agreement, the Company will also participate on a joint steering committee and a joint manufacturing subcommittee, with equal representation from both the Company and Novartis. Novartis has the exclusive right to develop and commercialize up to two candidates or products arising from the research activities. Subject to certain limitations pursuant to the terms of the Collaboration Agreement, Novartis will fund all development and commercialization costs. The Company will be responsible for manufacturing candidates and products for Novartis during the development and commercialization terms. The Company’s manufacturing activities will be reimbursed at cost during the development term and at cost plus a margin during the commercialization term, as defined in the Collaboration Agreement. If the Company is not able to manufacture candidates or products that meet the quality or quantity requirements of Novartis, then Novartis shall have the right to designate a third-party contract manufacturer or manufacture such candidates or products itself. In accordance with the Collaboration Agreement, taking into consideration Novartis’ election to discontinue the sickle cell disease program, the Company is also eligible to receive up to a total of $530.0 million in milestone payments, including up to $180.0 million in development milestone payments, up to $170.0 million in regulatory milestone payments and up to $180.0 million in commercial milestone payments, with respect to the licensed products. The Company is also eligible to earn tiered royalties on net sales of licensed products by Novartis, its affiliates or sublicensees, ranging from mid single-digit, to sub-teen double-digit percentages, and such royalties are potentially subject to various reductions and offsets. If any of the exploratory research efforts are advanced into formal research and development programs, the parties will negotiate the economics including potential milestone payments for such programs at that time. Unless earlier terminated, the Collaboration Agreement will continue on a target-by-target basis until the expiration of all applicable royalty terms with respect to all products that modulate such target on a country-by-country-basis. Either party may terminate the agreement on a target-by-target basis for the other party’s material breach with respect to such target, or in the event of the other party’s bankruptcy. Novartis may terminate the agreement for convenience on a target-by-target basis. The Company may terminate the agreement if Novartis files, or joins a third party in filing or maintaining, a patent challenge against certain of the patent rights licensed to Novartis under the terms of the agreement. There are no performance, cancellation, termination or refund provisions in the arrangement that contain material financial consequences to the Company. Revenue Recognition The Company 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. Since the option for Novartis to obtain manufacturing during the commercialization term from the Company is at a price that would reflect the standalone selling price, the option does not provide Novartis with a material right and is therefore not a performance obligation under the contract. The Company has concluded that the research, development and commercialization and manufacturing licenses are not distinct from the research activities and manufacturing during the research and development term as Novartis cannot benefit from the licenses without the Company performing the research and manufacturing services. These services are so specialized and rely on the Company’s expertise in gene editing technologies not available in the marketplace. As a result, these licenses have been combined with the research activities, service on the joint committees and the manufacturing during the research and development terms as a single performance obligation. The transaction price consists of the $33.3 million non-refundable upfront payment and projected reimbursable research and manufacturing activities, which have been estimated using the expected value method. None of the target fees or development and regulatory milestone payments have been included in the transaction price, as all are fully constrained. As part of the evaluation of the constraint, the Company considered numerous factors, including the fact that achievement of the milestones is outside of the Company’s control and is contingent upon the success of our preclinical studies, clinical trials, Novartis’ efforts and the receipt of regulatory approval. In addition, the Company has determined that the commercial milestones and sales-based royalties will be recognized when the related sales occur as they were determined to relate predominately to the licenses transferred to Novartis, and therefore have also been excluded from the transaction price. The Company will re-evaluate the transaction price, including estimated variable consideration included in the transaction price and all constrained amounts, in each reporting period and as uncertain events are resolved or other changes in circumstances occur. The Company identified only one performance obligation in the Collaboration Agreement. Therefore, the Company will allocate the transaction price at the onset of the contract to the single performance obligation. The Company recognizes revenue 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, 2019, the aggregate amount of the transaction price related to the unsatisfied portion of the performance obligation is $31.4 million, and the Company will recognize this revenue as the research and manufacturing activities are performed, which is expected to occur over a period of time that is estimated will conclude in 2027. The Company does not expect collaboration revenue to be recognized evenly over this period as it will be recognized on a percentage of completion basis as the Company performs the research, development and manufacturing services, which will likely vary from period to period. In estimating the total costs to satisfy its single performance obligation pursuant to the Novartis agreement, the Company is required to make significant estimates including the expected time it will take to fulfill the performance obligation, which currently is expected to be approximately ten years from the date the Collaboration Agreement was entered into, and the expected costs associated with manufacturing during the research and development terms for a novel manufacturing process as well as the probability of success of a target to move into the development phase. The Company has made estimates of such costs utilizing its experience with similar product candidates, however not identical to those in the Collaboration Agreement. In making such estimates, significant judgment is required to evaluate those key assumptions related to cost estimates. The cumulative effect of revisions to the total estimated costs to complete the Company’s single performance obligation will be recorded in the period in which the changes are identified and amounts can be reasonably estimated. While such revisions will have no impact on the Company’s reported cash flows, a significant change in these assumptions and estimates could have a material impact on the timing and amount of revenue recognized in future periods. In February 2019, Novartis elected to discontinue the sickle cell disease program under the Collaboration Agreement. Future costs associated with this target were removed from the estimated total costs in the cost-to-cost model, which resulted in an insignificant adjustment to revenue during the period. During the three months ended March 31, 2019 and 2018, the Company recognized revenue under the Collaboration Agreement of $0.3 million and $1.1 million, respectively, of which $0.1 million and $0.4 million was included in deferred revenue at the beginning of each such period. As of March 31, 2019 and December 31, 2018, there was approximately $31.4 million and $31.5 million of deferred revenue related to the Collaboration Agreement, respectively. In addition, as of March 31, 2019 and December 31, 2018, the Company has recorded accounts receivable of $0.2 million and $0.8 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.

Collaboration and License Agreement

3 Months Ended

Mar. 31, 2019

Organization Consolidation And Presentation Of Financial Statements [Abstract]

10. COLLABORATION AND LICENSE AGREEMENT

Summary of Agreement

In November 2017, the Company entered into a collaboration and license agreement (the “Collaboration Agreement”) with Novartis Institutes of BioMedical Research, Inc. (“Novartis”) 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. The Company continues to work with Novartis to identify new targets for the partnership based on the existing exploratory research component of the agreement, and the collaboration on ophthalmic programs also continues.

Under the terms of the Collaboration Agreement, taking into account Novartis’ election to discontinue the sickle cell disease program, 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 the ophthalmic targets. Upon entering into the Collaboration Agreement, the Company received an upfront, nonrefundable payment of $35.0 million and issued additional shares of its Series B preferred stock to Novartis for consideration of $10.0 million. The Company recorded the Series B preferred stock at its estimated fair value of $11.7 million, including $1.7 million of the upfront payment, and allocated the remaining $33.3 million of the upfront payment to the Collaboration Agreement.

The Collaboration Agreement consists of a research term, where the Company and Novartis are collaborating to perform research and conduct preclinical development to identify candidates that modulate the ophthalmic targets. The Collaboration Agreement also includes exploratory work on the applicability of the gene-editing technology with respect to other gene targets. The Company’s obligation to perform such exploratory research concludes in November 2020. Novartis may select up to two targets, with limited substitution rights. The Company is responsible for the manufacturing of proprietary research grade human hematopoietic stem cell derived adeno-associated virus vectors (“AAVHSCs”) during the research term. Research activities performed by the Company are being reimbursed at a full-time equivalent rate (“FTE”) and manufacturing activities will be reimbursed at cost, up to a maximum of $17.0 million during the research term, as specified and defined in the Collaboration Agreement. Novartis is required to pay the Company a target fee of $5.0 million for each target that meets certain success criteria during the research term (the “target fee trigger date”), up to a maximum of two targets. The research term will continue for five years from the effective date of the Collaboration Agreement. Pursuant to the Collaboration Agreement, the Company will also participate on a joint steering committee and a joint manufacturing subcommittee, with equal representation from both the Company and Novartis.

Novartis has the exclusive right to develop and commercialize up to two candidates or products arising from the research activities. Subject to certain limitations pursuant to the terms of the Collaboration Agreement, Novartis will fund all development and commercialization costs. The Company will be responsible for manufacturing candidates and products for Novartis during the development and commercialization terms. The Company’s manufacturing activities will be reimbursed at cost during the development term and at cost plus a margin during the commercialization term, as defined in the Collaboration Agreement. If the Company is not able to manufacture candidates or products that meet the quality or quantity requirements of Novartis, then Novartis shall have the right to designate a third-party contract manufacturer or manufacture such candidates or products itself.

In accordance with the Collaboration Agreement, taking into consideration Novartis’ election to discontinue the sickle cell disease program, the Company is also eligible to receive up to a total of $530.0 million in milestone payments, including up to $180.0 million in development milestone payments, up to $170.0 million in regulatory milestone payments and up to $180.0 million in commercial milestone payments, with respect to the licensed products. The Company is also eligible to earn tiered royalties on net sales of licensed products by Novartis, its affiliates or sublicensees, ranging from mid single-digit, to sub-teen double-digit percentages, and such royalties are potentially subject to various reductions and offsets. If any of the exploratory research efforts are advanced into formal research and development programs, the parties will negotiate the economics including potential milestone payments for such programs at that time.

Unless earlier terminated, the Collaboration Agreement will continue on a target-by-target basis until the expiration of all applicable royalty terms with respect to all products that modulate such target on a country-by-country-basis. Either party may terminate the agreement on a target-by-target basis for the other party’s material breach with respect to such target, or in the event of the other party’s bankruptcy. Novartis may terminate the agreement for convenience on a target-by-target basis. The Company may terminate the agreement if Novartis files, or joins a third party in filing or maintaining, a patent challenge against certain of the patent rights licensed to Novartis under the terms of the agreement. There are no performance, cancellation, termination or refund provisions in the arrangement that contain material financial consequences to the Company.

Revenue Recognition

The Company 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. Since the option for Novartis to obtain manufacturing during the commercialization term from the Company is at a price that would reflect the standalone selling price, the option does not provide Novartis with a material right and is therefore not a performance obligation under the contract.

The Company has concluded that the research, development and commercialization and manufacturing licenses are not distinct from the research activities and manufacturing during the research and development term as Novartis cannot benefit from the licenses without the Company performing the research and manufacturing services. These services are so specialized and rely on the Company’s expertise in gene editing technologies not available in the marketplace. As a result, these licenses have been combined with the research activities, service on the joint committees and the manufacturing during the research and development terms as a single performance obligation.

The transaction price consists of the $33.3 million non-refundable upfront payment and projected reimbursable research and manufacturing activities, which have been estimated using the expected value method. None of the target fees or development and regulatory milestone payments have been included in the transaction price, as all are fully constrained. As part of the evaluation of the constraint, the Company considered numerous factors, including the fact that achievement of the milestones is outside of the Company’s control and is contingent upon the success of our preclinical studies, clinical trials, Novartis’ efforts and the receipt of regulatory approval. In addition, the Company has determined that the commercial milestones and sales-based royalties will be recognized when the related sales occur as they were determined to relate predominately to the licenses transferred to Novartis, and therefore have also been excluded from the transaction price. The Company will re-evaluate the transaction price, including estimated variable consideration included in the transaction price and all constrained amounts, in each reporting period and as uncertain events are resolved or other changes in circumstances occur.

The Company identified only one performance obligation in the Collaboration Agreement. Therefore, the Company will allocate the transaction price at the onset of the contract to the single performance obligation.

The Company recognizes revenue 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, 2019, the aggregate amount of the transaction price related to the unsatisfied portion of the performance obligation is $31.4 million, and the Company will recognize this revenue as the research and manufacturing activities are performed, which is expected to occur over a period of time that is estimated will conclude in 2027. The Company does not expect collaboration revenue to be recognized evenly over this period as it will be recognized on a percentage of completion basis as the Company performs the research, development and manufacturing services, which will likely vary from period to period.

In estimating the total costs to satisfy its single performance obligation pursuant to the Novartis agreement, the Company is required to make significant estimates including the expected time it will take to fulfill the performance obligation, which currently is expected to be approximately ten years from the date the Collaboration Agreement was entered into, and the expected costs associated with manufacturing during the research and development terms for a novel manufacturing process as well as the probability of success of a target to move into the development phase. The Company has made estimates of such costs utilizing its experience with similar product candidates, however not identical to those in the Collaboration Agreement. In making such estimates, significant judgment is required to evaluate those key assumptions related to cost estimates. The cumulative effect of revisions to the total estimated costs to complete the Company’s single performance obligation will be recorded in the period in which the changes are identified and amounts can be reasonably estimated. While such revisions will have no impact on the Company’s reported cash flows, a significant change in these assumptions and estimates could have a material impact on the timing and amount of revenue recognized in future periods.

In February 2019, Novartis elected to discontinue the sickle cell disease program under the Collaboration Agreement. Future costs associated with this target were removed from the estimated total costs in the cost-to-cost model, which resulted in an insignificant adjustment to revenue during the period.

During the three months ended March 31, 2019 and 2018, the Company recognized revenue under the Collaboration Agreement of $0.3 million and $1.1 million, respectively, of which $0.1 million and $0.4 million was included in deferred revenue at the beginning of each such period. As of March 31, 2019 and December 31, 2018, there was approximately $31.4 million and $31.5 million of deferred revenue related to the Collaboration Agreement, respectively. In addition, as of March 31, 2019 and December 31, 2018, the Company has recorded accounts receivable of $0.2 million and $0.8 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.