Commitments and Contingencies	3 Months Ended
Mar. 31, 2021
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	6. Commitments and Contingencies Future Lease Commitments The Company has entered into certain leasing commitments for which right of use assets and right of use liabilities are not reflected on the consolidated balance sheet as the leases have not yet commenced. In November 2019, the Company, together with one of its partners, committed to making $3.9 million in annual rental payments to a clinical manufacturing organization under a lease arrangement for a five-year period following commencement of the lease arrangement. The lease arrangement is expected to commence in the second quarter of 2021 and all payments will be split equally between the Company and its partner. In July 2020, the Company entered into a lease agreement for an office and laboratory facility in Boston, Massachusetts, or the 2020 Boston Lease. In accordance with ASC 842, Leases, lease commencement for the 2020 Boston Lease is expected in the second half of 2021. Rent commencement is expected in the first half of 2022. In connection therewith, the Company has committed to making at least $292.5 million in rental payments over a lease term of 152 months. The Company is also obligated to make certain future payments related to the construction of leasehold improvements. Litigation In the ordinary course of business, the Company is from time to time involved in lawsuits, investigations, proceedings and threats of litigation related to, among other things, the Company’s intellectual property estate (including certain in-licensed intellectual property), commercial arrangements and other matters. Such proceedings may include quasi-litigation, inter partes administrative proceedings in the U.S. Patent and Trademark Office and the European Patent Office involving the Company’s intellectual property estate including certain in-licensed intellectual property. The outcome of any of the foregoing, regardless of the merits, is inherently uncertain. In addition, litigation and related matters are costly and may divert the attention of Company’s management and other resources that would otherwise be engaged in other activities. If the Company is unable to prevail in any such proceedings, the Company’s business, results of operations, liquidity and financial condition could be adversely affected. Letters of Credit As of March 31, 2021, the Company had restricted cash of $16.8 million, representing letters of credit securing the Company’s obligations under certain leased facilities. The letters of credit are secured by cash held in a restricted depository account. The cash deposit is recorded in restricted cash in the accompanying condensed consolidated balance sheet as of March 31, 2021. Research, Manufacturing, License and Intellectual Property Agreements The Company has engaged several research institutions and companies to identify new delivery strategies and applications of the Company’s gene-editing technology. The Company is also a party to a number of license agreements which require significant upfront payments and may be required to make future royalty payments and potential milestone payments from time to time. In addition, the Company is also a party to intellectual property agreements, which require maintenance and milestone payments from time to time. Further, the Company is a party to a number of manufacturing agreements that require upfront payments for the future performance of services. In association with these agreements, on a product-by-product basis, the counterparties are eligible to receive up to low eight-digit potential payments upon specified research, development and regulatory milestones. In addition, on a product-by-product basis, the counterparties are eligible to receive potential commercial milestone payments based on specified annual sales thresholds. The potential payments are low-single digit percentages of the specified annual sales thresholds. The counterparties are also eligible to receive low single-digit royalties on future net sales. Under certain circumstances and if certain contingent future events occur, Vertex Pharmaceuticals Incorporated and certain of its subsidiaries, or Vertex, is eligible to receive up to $395.0 million in potential specified research, development, regulatory and commercial milestones and tiered single-digit percentage royalties on future net sales. Refer to Note 7 for further discussion on the Company’s arrangements with Vertex.

Commitments and Contingencies

3 Months Ended

Mar. 31, 2021

Commitments And Contingencies Disclosure [Abstract]

6. Commitments and Contingencies

Future Lease Commitments

The Company has entered into certain leasing commitments for which right of use assets and right of use liabilities are not reflected on the consolidated balance sheet as the leases have not yet commenced.

In November 2019, the Company, together with one of its partners, committed to making $3.9 million in annual rental payments to a clinical manufacturing organization under a lease arrangement for a five-year period following commencement of the lease arrangement. The lease arrangement is expected to commence in the second quarter of 2021 and all payments will be split equally between the Company and its partner.

In July 2020, the Company entered into a lease agreement for an office and laboratory facility in Boston, Massachusetts, or the 2020 Boston Lease. In accordance with ASC 842, Leases, lease commencement for the 2020 Boston Lease is expected in the second half of 2021. Rent commencement is expected in the first half of 2022. In connection therewith, the Company has committed to making at least $292.5 million in rental payments over a lease term of 152 months. The Company is also obligated to make certain future payments related to the construction of leasehold improvements.

Litigation

In the ordinary course of business, the Company is from time to time involved in lawsuits, investigations, proceedings and threats of litigation related to, among other things, the Company’s intellectual property estate (including certain in-licensed intellectual property), commercial arrangements and other matters. Such proceedings may include quasi-litigation, inter partes administrative proceedings in the U.S. Patent and Trademark Office and the European Patent Office involving the Company’s intellectual property estate including certain in-licensed intellectual property. The outcome of any of the foregoing, regardless of the merits, is inherently uncertain. In addition, litigation and related matters are costly and may divert the attention of Company’s management and other resources that would otherwise be engaged in other activities. If the Company is unable to prevail in any such proceedings, the Company’s business, results of operations, liquidity and financial condition could be adversely affected.

Letters of Credit

As of March 31, 2021, the Company had restricted cash of $16.8 million, representing letters of credit securing the Company’s obligations under certain leased facilities. The letters of credit are secured by cash held in a restricted depository account. The cash deposit is recorded in restricted cash in the accompanying condensed consolidated balance sheet as of March 31, 2021.

Research, Manufacturing, License and Intellectual Property Agreements

The Company has engaged several research institutions and companies to identify new delivery strategies and applications of the Company’s gene-editing technology. The Company is also a party to a number of license agreements which require significant upfront payments and may be required to make future royalty payments and potential milestone payments from time to time. In addition, the Company is also a party to intellectual property agreements, which require maintenance and milestone payments from time to time. Further, the Company is a party to a number of manufacturing agreements that require upfront payments for the future performance of services.

In association with these agreements, on a product-by-product basis, the counterparties are eligible to receive up to low eight-digit potential payments upon specified research, development and regulatory milestones. In addition, on a product-by-product basis, the counterparties are eligible to receive potential commercial milestone payments based on specified annual sales thresholds. The potential payments are low-single digit percentages of the specified annual sales thresholds. The counterparties are also eligible to receive low single-digit royalties on future net sales.

Under certain circumstances and if certain contingent future events occur, Vertex Pharmaceuticals Incorporated and certain of its subsidiaries, or Vertex, is eligible to receive up to $395.0 million in potential specified research, development, regulatory and commercial milestones and tiered single-digit percentage royalties on future net sales. Refer to Note 7 for further discussion on the Company’s arrangements with Vertex.