SUBSEQUENT EVENTS	12 Months Ended
Dec. 31, 2018
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	NOTE 13. SUBSEQUENT EVENTS On January 28, 2019, the Company entered into a collaboration and license agreement with a clinical-stage gene therapy company, Voyager Therapeutics, Inc., or Voyager. The collaboration is focused on the development and commercialization of four programs using Voyager’s proprietary gene therapy platforms. The four programs consist of Voyager’s VY-AADC program for Parkinson’s disease, Voyager’s VY-FXN01 program for Friedreich’s ataxia, as well as rights to two programs to be determined by the parties in the future. In connection with the agreement, the Company agreed to pay Voyager a $115 million upfront cash payment and entered into an agreement to purchase $50 million of Voyager’s common stock. Pursuant to development plans agreed to by the Company and Voyager, unless Voyager exercises the co-development and co-commercialization rights that are described below, the Company has agreed to be responsible for all development costs. Upon the occurrence of a specified event for each program, the Company has agreed to assume responsibility for development, manufacturing, and commercialization activities for such program. Additionally, Voyager may be entitled to earn up to $1.7 billion in development, regulatory, and commercial milestones across the four programs and royalties for net sales in and outside the U.S. Under the terms of the agreement, on a program-by-program basis, upon the achievement of milestones or metrics specified in the agreement for VY-AADC and VY-FXN01, Voyager will have the option to co-develop and co-commercialize such program with the Company in the U.S. under cost- and profit-sharing arrangements, and Voyager agrees to forfeit certain milestones and royalties related to such program for which Voyager has exercised its co-develop and co-commercialize option. The effectiveness of the agreement and the closing of the sale and issuance of the Voyager common stock described above are subject to certain conditions, including the expiration or termination of the applicable waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, and other customary closing conditions.

SUBSEQUENT EVENTS

12 Months Ended

Dec. 31, 2018

NOTE 13. SUBSEQUENT EVENTS

On January 28, 2019, the Company entered into a collaboration and license agreement with a clinical-stage gene therapy company, Voyager Therapeutics, Inc., or Voyager. The collaboration is focused on the development and commercialization of four programs using Voyager’s proprietary gene therapy platforms. The four programs consist of Voyager’s VY-AADC program for Parkinson’s disease, Voyager’s VY-FXN01 program for Friedreich’s ataxia, as well as rights to two programs to be determined by the parties in the future. In connection with the agreement, the Company agreed to pay Voyager a $115 million upfront cash payment and entered into an agreement to purchase $50 million of Voyager’s common stock. Pursuant to development plans agreed to by the Company and Voyager, unless Voyager exercises the co-development and co-commercialization rights that are described below, the Company has agreed to be responsible for all development costs. Upon the occurrence of a specified event for each program, the Company has agreed to assume responsibility for development, manufacturing, and commercialization activities for such program. Additionally, Voyager may be entitled to earn up to $1.7 billion in development, regulatory, and commercial milestones across the four programs and royalties for net sales in and outside the U.S.

Under the terms of the agreement, on a program-by-program basis, upon the achievement of milestones or metrics specified in the agreement for VY-AADC and VY-FXN01, Voyager will have the option to co-develop and co-commercialize such program with the Company in the U.S. under cost- and profit-sharing arrangements, and Voyager agrees to forfeit certain milestones and royalties related to such program for which Voyager has exercised its co-develop and co-commercialize option.

The effectiveness of the agreement and the closing of the sale and issuance of the Voyager common stock described above are subject to certain conditions, including the expiration or termination of the applicable waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, and other customary closing conditions.