License Agreements	9 Months Ended
Sep. 30, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
License Agreements	3. LICENSE AGREEMENTS REGENXBIO Inc. In August 2017, the Company entered into a License Agreement, or the REGENXBIO GBA1 License, with REGENXBIO Inc., or REGENXBIO. Under the terms of the REGENXBIO GBA1 License, REGENXBIO granted the Company an exclusive, worldwide license under certain patents and patent applications to make, have made, use, import, sell and offer for sale products for the treatment of disease, including but not limited to Parkinson’s disease and Gaucher disease, whether or not caused by mutations in the gene that produces the GBA1 enzyme in humans by in vivo gene therapy using AAV9 delivering the gene (or any portion thereof) encoding for GBA1. As consideration for the licensed rights under the REGENXBIO GBA1 License, the Company issued 2,430,000 shares of its common stock with an aggregate fair value of $0.4 million in a concurrent private placement to REGENXBIO. The Company is obligated, pursuant to the REGENXBIO GBA1 License, to pay REGENXBIO: (1) an annual maintenance fee; (2) mid-to high-single digit royalty percentages on net sales of licensed products, subject to reduction in specified circumstances; and (3) mid-teen to low-twenties royalty percentages of any sublicense fees the Company receives from sublicensees for the licensed intellectual property rights. The REGENXBIO GBA1 License will expire on a country-by-country, licensed product-by-licensed product basis upon the later of (1) the expiration, lapse, abandonment or invalidation of the last valid claim of the licensed intellectual property and (2) seven years from the first commercial sale of each licensed product. In May 2018, the Company entered into a license agreement, or the REGENXBIO Option Genes License, with REGENXBIO pursuant to which REGENXBIO granted the Company three distinct exclusive options for specified genes, or the Option Genes, exercisable at the Company’s sole discretion through May 10, 2019. Each option represented the right to obtain an exclusive, worldwide license under certain patents and patent applications to make, have made, use, import, sell and offer for sale products for the treatment or prevention of disease, including but not limited to Parkinson’s disease, whether or not caused by mutations in any Option Gene that is the subject of the applicable license, in humans by in vivo gene therapy using AAV9 delivering the applicable licensed Option Gene and/or RNA interference or antisense modalities that target the applicable licensed Option Gene. The Company also received a non-exclusive, royalty-free, worldwide research license to perform research and development activities for each Option Gene solely for purposes of evaluating whether to exercise the applicable option. In April 2019, the Company exercised all of the options under the REGENXBIO Option Genes License and paid the additional up-front fee of $0.6 million per option for an aggregate of $1.8 million to REGENXBIO. In May 2020, the Company incurred annual maintenance fees of approximately $0.1 million per option for an aggregate total of approximately $0.2 million to REGENXBIO. Under the terms of the REGENXBIO Option Genes License, the Company is required to pay REGENXBIO: (1) an annual maintenance fee; (2) mid- to high-single digit royalty percentages on net sales of the licensed product, subject to reduction in specified circumstances; and (3) mid-teen to low-twenties royalty percentages of any sublicense fees the Company receives from sublicensees for the licensed intellectual property rights. If a licensed product includes the GBA1 gene and otherwise would be subject to royalties under the REGENXBIO GBA1 License, then royalties for that licensed product will only be due under the REGENXBIO Option Genes License. The REGENXBIO Option Genes License will expire on a country-by-country, licensed product-by-licensed product basis upon the later of (1) the expiration, lapse, abandonment or invalidation of the last valid claim of the licensed intellectual property and (2) seven years from the first commercial sale of each licensed product.

License Agreements

9 Months Ended

Sep. 30, 2020

Organization Consolidation And Presentation Of Financial Statements [Abstract]

3. LICENSE AGREEMENTS

REGENXBIO Inc.

In August 2017, the Company entered into a License Agreement, or the REGENXBIO GBA1 License, with REGENXBIO Inc., or REGENXBIO. Under the terms of the REGENXBIO GBA1 License, REGENXBIO granted the Company an exclusive, worldwide license under certain patents and patent applications to make, have made, use, import, sell and offer for sale products for the treatment of disease, including but not limited to Parkinson’s disease and Gaucher disease, whether or not caused by mutations in the gene that produces the GBA1 enzyme in humans by in vivo gene therapy using AAV9 delivering the gene (or any portion thereof) encoding for GBA1.

As consideration for the licensed rights under the REGENXBIO GBA1 License, the Company issued 2,430,000 shares of its common stock with an aggregate fair value of $0.4 million in a concurrent private placement to REGENXBIO. The Company is obligated, pursuant to the REGENXBIO GBA1 License, to pay REGENXBIO: (1) an annual maintenance fee; (2) mid-to high-single digit royalty percentages on net sales of licensed products, subject to reduction in specified circumstances; and (3) mid-teen to low-twenties royalty percentages of any sublicense fees the Company receives from sublicensees for the licensed intellectual property rights.

The REGENXBIO GBA1 License will expire on a country-by-country, licensed product-by-licensed product basis upon the later of (1) the expiration, lapse, abandonment or invalidation of the last valid claim of the licensed intellectual property and (2) seven years from the first commercial sale of each licensed product.

In May 2018, the Company entered into a license agreement, or the REGENXBIO Option Genes License, with REGENXBIO pursuant to which REGENXBIO granted the Company three distinct exclusive options for specified genes, or the Option Genes, exercisable at the Company’s sole discretion through May 10, 2019. Each option represented the right to obtain an exclusive, worldwide license under certain patents and patent applications to make, have made, use, import, sell and offer for sale products for the treatment or prevention of disease, including but not limited to Parkinson’s disease, whether or not caused by mutations in any Option Gene that is the subject of the applicable license, in humans by in vivo gene therapy using AAV9 delivering the applicable licensed Option Gene and/or RNA interference or antisense modalities that target the applicable licensed Option Gene. The Company also received a non-exclusive, royalty-free, worldwide research license to perform research and development activities for each Option Gene solely for purposes of evaluating whether to exercise the applicable option.

In April 2019, the Company exercised all of the options under the REGENXBIO Option Genes License and paid the additional up-front fee of $0.6 million per option for an aggregate of $1.8 million to REGENXBIO. In May 2020, the Company incurred annual maintenance fees of approximately $0.1 million per option for an aggregate total of approximately $0.2 million to REGENXBIO.

Under the terms of the REGENXBIO Option Genes License, the Company is required to pay REGENXBIO: (1) an annual maintenance fee; (2) mid- to high-single digit royalty percentages on net sales of the licensed product, subject to reduction in specified circumstances; and (3) mid-teen to low-twenties royalty percentages of any sublicense fees the Company receives from sublicensees for the licensed intellectual property rights. If a licensed product includes the GBA1 gene and otherwise would be subject to royalties under the REGENXBIO GBA1 License, then royalties for that licensed product will only be due under the REGENXBIO Option Genes License.

The REGENXBIO Option Genes License will expire on a country-by-country, licensed product-by-licensed product basis upon the later of (1) the expiration, lapse, abandonment or invalidation of the last valid claim of the licensed intellectual property and (2) seven years from the first commercial sale of each licensed product.