LITIGATION SETTLEMENT AND LICENSE AGREEMENTS	9 Months Ended
Sep. 30, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
LITIGATION SETTLEMENT AND LICENSE AGREEMENTS	3. LITIGATION SETTLEMENT AND LICENSE AGREEMENTS In July 2017, the Company and the University of Western Australia (“UWA”) entered into a settlement agreement with BioMarin Leiden Holding BV, its subsidiaries BioMarin Nederlands BV and BioMarin Technologies BV (collectively, “BioMarin”). On the same day, the Company entered into a license agreement with BioMarin and Academisch Ziekenhuis Leiden (“AZL”) (collectively with the Company, UWA and BioMarin, the “Settlement Parties”). Under these agreements, BioMarin agreed to provide the Company with an exclusive license to certain intellectual property with an option to convert the exclusive license into a co-exclusive license and the Settlement Parties agreed to stop most existing efforts to continue with ongoing litigation and opposition and other administrative proceedings concerning BioMarin’s intellectual property. Under terms of the agreements, the Company agreed to make total up-front payments of $35.0 million upon execution of the agreements, consisting of $20.0 million under the settlement agreement and $15.0 million under the license agreement. Additionally, the Company may be liable for up to approximately $65.0 million in regulatory and sales milestones for eteplirsen as well as exon 45 and exon 53 skipping product candidates. BioMarin will also be eligible to receive royalty payments, ranging from 4% - 8%, for exon 51 skipping products, exon 45 skipping products and exon 53 skipping products. The royalty terms under the license agreement will expire in December 2023 in the U.S. and September 2024 in the EU. In July 2017, the Company made the cash payment of $35.0 million to BioMarin. Accordingly, as of September 30, 2017, the Company has recorded an intangible asset in the U.S. of $6.6 million on its unaudited condensed consolidated balance sheet. For the three and nine months ended September 30, 2017, the Company recorded $25.6 million and $28.4 million settlement and license charges, respectively, in its unaudited condensed consolidated statements of operations and comprehensive loss. The intangible asset represents the fair value of the U.S. license to BioMarin’s intellectual property related to EXONDYS 51, which was determined by an income-based approach, and will be amortized on a straight-line basis over the remaining life of the patent. For both the three and nine months ended September 30, 2017, the Company recognized intangible asset amortization expense and royalties of approximately $0.8 million and $2.3 million, respectively. The royalties are included in cost of sales in the Company’s unaudited condensed consolidated statements of operations and comprehensive loss.

3. LITIGATION SETTLEMENT AND LICENSE AGREEMENTS

In July 2017, the Company and the University of Western Australia (“UWA”) entered into a settlement agreement with BioMarin Leiden Holding BV, its subsidiaries BioMarin Nederlands BV and BioMarin Technologies BV (collectively, “BioMarin”). On the same day, the Company entered into a license agreement with BioMarin and Academisch Ziekenhuis Leiden (“AZL”) (collectively with the Company, UWA and BioMarin, the “Settlement Parties”). Under these agreements, BioMarin agreed to provide the Company with an exclusive license to certain intellectual property with an option to convert the exclusive license into a co-exclusive license and the Settlement Parties agreed to stop most existing efforts to continue with ongoing litigation and opposition and other administrative proceedings concerning BioMarin’s intellectual property. Under terms of the agreements, the Company agreed to make total up-front payments of $35.0 million upon execution of the agreements, consisting of $20.0 million under the settlement agreement and $15.0 million under the license agreement. Additionally, the Company may be liable for up to approximately $65.0 million in regulatory and sales milestones for eteplirsen as well as exon 45 and exon 53 skipping product candidates. BioMarin will also be eligible to receive royalty payments, ranging from 4% - 8%, for exon 51 skipping products, exon 45 skipping products and exon 53 skipping products. The royalty terms under the license agreement will expire in December 2023 in the U.S. and September 2024 in the EU.

In July 2017, the Company made the cash payment of $35.0 million to BioMarin. Accordingly, as of September 30, 2017, the Company has recorded an intangible asset in the U.S. of $6.6 million on its unaudited condensed consolidated balance sheet. For the three and nine months ended September 30, 2017, the Company recorded $25.6 million and $28.4 million settlement and license charges, respectively, in its unaudited condensed consolidated statements of operations and comprehensive loss.

The intangible asset represents the fair value of the U.S. license to BioMarin’s intellectual property related to EXONDYS 51, which was determined by an income-based approach, and will be amortized on a straight-line basis over the remaining life of the patent. For both the three and nine months ended September 30, 2017, the Company recognized intangible asset amortization expense and royalties of approximately $0.8 million and $2.3 million, respectively. The royalties are included in cost of sales in the Company’s unaudited condensed consolidated statements of operations and comprehensive loss.