Description of Business	12 Months Ended
Dec. 31, 2017
Description of Business
Description of Business	1. Description of Business Corporate Information, Status of Operations, and Management Plans Amicus Therapeutics, Inc. (the "Company") is a global patient-centric biotechnology company engaged in the discovery, development and commercialization of a diverse set of novel high-quality treatments for patients living with rare metabolic diseases. The cornerstone of the Amicus portfolio is migalastat HCl, an oral precision medicine for people living with Fabry disease who have amenable genetic mutations. Migalastat is currently approved under the trade name GALAFOLD in the European Union, with additional approvals granted and pending in several geographies. For Fabry patients with non-amenable genetic mutations, a novel proprietary enzyme replacement therapy ("ERT") co-formulated with migalastat HCl is currently in late preclinical development. The future value driver of the Amicus pipeline is ATB200/AT2221, a novel, late-stage, potential best-in-class treatment paradigm for Pompe disease. ATB200/AT2221 leverages our Chaperone-Advanced Replacement Therapy ("CHART®") platform technology to develop novel ERT products for Pompe disease, Fabry disease, and potentially other lysosomal storage disorders ("LSDs"). The Company is also investigating preclinical and discovery programs in other rare diseases including cyclin-dependent kinase-like 5 ("CDKL5") deficiency. The Company believes that its platform technologies and its product pipeline uniquely position them and drive their commitment to advancing and expanding a robust pipeline of cutting-edge, first- or best-in-class medicines for rare metabolic diseases. The Company was previously developing SD-101 in late-stage development as a potential first-to-market therapy for the chronic, rare connective tissue disorder Epidermolysis Bullosa ("EB"). On September 13, 2017, the Company reported that top-line data from the randomized, double-blind, placebo-controlled Phase 3 clinical study ("ESSENCE" or "SD-005") to assess the efficacy and safety of the novel topical wound-healing agent SD-101 did not meet the primary endpoints or secondary endpoints in participants with EB. The Company plans to further analyze and share the Phase 3 ESSENCE results with key stakeholders in the EB community including physicians, patient organizations and regulators. In the interim, in consultation with their physicians, participants in the ongoing extension studies (SD-004 and -006) will have the opportunity to continue being treated with SD-101. Based on the top-line data, the Company has no current plans to invest in any additional clinical studies or commercial preparation activities for SD-101. This event led the Company to assess the carrying amount of the program's tangible and intangible assets against their respective fair values. Based on the assessment, the Company recognized a loss on impairment of intangible assets in the amount of $463.7 million and $1.7 million in fixed assets recorded within Loss on Impairment of Assets within the Consolidated Statements of Operations. Since the study did not meet the primary and secondary endpoints, the Company has concluded that they will not make the potential milestone payments indicated in the Asset Purchase Agreement to the former Scioderm holders. Accordingly, the Company recognized a gain of $254.7 million in Changes in Fair Value of Contingent Consideration Payable in the third quarter of 2017, in order to decrease the liability to zero. The Company also recognized $0.4 million in selling, general and administrative costs and $8.1 million in research and development expenses related to the wind-down of operations for the Phase 3 ESSENCE study and ongoing extension studies SD-004 and SD-006, as well as income tax benefit of $164.7 million due to the reduction of the deferred tax liability related to Scioderm IPR&D, in the Consolidated Statements of Operations in the third quarter of 2017. See "— Note 4. Goodwill and IPR&D" for more details. On February 15, 2018, the Company announced the pricing of an underwritten offering of 19,354,839 shares of its common stock at $15.50 per shares, resulting in gross proceeds of $300.0 million, before deducting underwriting discounts and commissions and offering expenses payable by the Company. The offering closed on February 21, 2018 and the Company received net proceeds of $282.0 million from the Offering, after deducting underwriting discounts and commissions and offering expenses payable by the Company. J.P. Morgan Securities LLC and Goldman Sachs & Co. LLC were acting as joint lead book-running managers, Cowen and Leerink Partners were acting as co-book-running managers, and BofA Merrill Lynch was acting as lead co-manager for the offering. The Company expects to use the net proceeds of the offering for investment in the U.S. and international commercial infrastructure for migalastat HCl, investment in manufacturing capabilities for ATB200, the continued clinical development of its product candidates, research and development expenditures, clinical and pre-clinical trial expenditures, commercialization expenditures and for other general corporate purposes. In July 2017, the Company entered into an underwriting agreement ("the Underwriting Agreement") with J.P. Morgan Securities LLC and Goldman Sachs & Co. LLC, as representatives of the several underwriters set forth on Schedule 1 thereto, relating to an underwritten public offering of the Company's common stock (the "Offering"). Under the terms of the Underwriting Agreement, the Company issued and sold 21,122,449 shares at a price to the public of $12.25 per share, resulting in gross proceeds of $258.8 million, before deducting underwriting discounts and commissions and offering expenses payable by the Company. The Offering closed on July 18, 2017 and the Company received net proceeds from the Offering, after deducting underwriting discounts and commissions and offering expenses payable by the Company of $243.0 million. See "— Note 9. Equity" for more details. In December 2016, the Company issued $250 million aggregate principal amount of 3.00% unsecured Convertible Senior Notes due 2023 (the "Convertible Notes"), in a private offering to qualified institutional buyers pursuant to Rule 144A under the Securities Act of 1933, as amended (the "Securities Act"). Interest is payable semiannually on June 15 and December 15 of each year, beginning on June 15, 2017. The Notes will mature on December 15, 2023, unless earlier repurchased, redeemed, or converted in accordance with their terms. The Notes are convertible at the option of the holders, under certain circumstances and during certain periods, into cash, shares of the Company's common stock, par value $0.01 per share ("Common Stock"), or a combination thereof. The net proceeds from the issuance of the Convertible Note offering were $243.0 million, after deducting fees and estimated expenses payable by the Company. In addition, the Company used approximately $13.5 million of the net proceeds from the issuance of the Convertible Notes to pay the cost of the capped call transactions ("Capped Call Confirmations") that the Company entered into in connection with the issuance of the Convertible Notes. For additional information, see "— Note 11. Debt Instruments and Related Party Transactions." In July 2016, the Company expanded its biologics pipeline with a new preclinical program for CDKL5 deficiency, a rare and devastating genetic neurological disease for which there is no currently approved treatment. The Company has obtained the rights and related intellectual property to a preclinical CDKL5 program through its acquisition of MiaMed, Inc. ("MiaMed"). The aggregate value of the deal was approximately $89.5 million, which included an upfront payment of $6.5 million and Company stock, cash and potential milestones of up to $83.0 million. For additional information, see "— Note 3. Acquisitions". Beginning in April 2016 and through July 2016, the Company sold 15.0 million shares of Common Stock under an at-the-market ("ATM") equity program with Cowen and Company, LLC ("Cowen") acting as sales agent. Cowen was compensated at a fixed commission rate up to 3.0%. The ATM sales agreement resulted in net proceeds of $97.1 million, after Cowen's commission of $2.7 million and other expenses of $0.2 million. The Company has completed all sales under the ATM equity program. The Company had an accumulated deficit of approximately $1.1 billion at December 31, 2017 and anticipates incurring losses through the fiscal year ending December 31, 2018 and beyond. The Company has been able to fund its operating losses to date through stock offering, debt issuances, and payments from partners during the terms of the collaboration agreements and other financing arrangements. The current cash position, including proceeds from the recent equity offering and expected Galafold revenues, is sufficient to fund ongoing Fabry and Pompe program operations into at least 2021. Potential future business development collaborations, pipeline expansion, and investment in biologics manufacturing capabilities could impact the Company's future capital requirements.

1. Description of Business

Corporate Information, Status of Operations, and Management Plans

Amicus Therapeutics, Inc. (the "Company") is a global patient-centric biotechnology company engaged in the discovery, development and commercialization of a diverse set of novel high-quality treatments for patients living with rare metabolic diseases. The cornerstone of the Amicus portfolio is migalastat HCl, an oral precision medicine for people living with Fabry disease who have amenable genetic mutations. Migalastat is currently approved under the trade name GALAFOLD in the European Union, with additional approvals granted and pending in several geographies. For Fabry patients with non-amenable genetic mutations, a novel proprietary enzyme replacement therapy ("ERT") co-formulated with migalastat HCl is currently in late preclinical development.

The future value driver of the Amicus pipeline is ATB200/AT2221, a novel, late-stage, potential best-in-class treatment paradigm for Pompe disease. ATB200/AT2221 leverages our Chaperone-Advanced Replacement Therapy ("CHART®") platform technology to develop novel ERT products for Pompe disease, Fabry disease, and potentially other lysosomal storage disorders ("LSDs"). The Company is also investigating preclinical and discovery programs in other rare diseases including cyclin-dependent kinase-like 5 ("CDKL5") deficiency. The Company believes that its platform technologies and its product pipeline uniquely position them and drive their commitment to advancing and expanding a robust pipeline of cutting-edge, first- or best-in-class medicines for rare metabolic diseases.

The Company was previously developing SD-101 in late-stage development as a potential first-to-market therapy for the chronic, rare connective tissue disorder Epidermolysis Bullosa ("EB"). On September 13, 2017, the Company reported that top-line data from the randomized, double-blind, placebo-controlled Phase 3 clinical study ("ESSENCE" or "SD-005") to assess the efficacy and safety of the novel topical wound-healing agent SD-101 did not meet the primary endpoints or secondary endpoints in participants with EB. The Company plans to further analyze and share the Phase 3 ESSENCE results with key stakeholders in the EB community including physicians, patient organizations and regulators. In the interim, in consultation with their physicians, participants in the ongoing extension studies (SD-004 and -006) will have the opportunity to continue being treated with SD-101. Based on the top-line data, the Company has no current plans to invest in any additional clinical studies or commercial preparation activities for SD-101. This event led the Company to assess the carrying amount of the program's tangible and intangible assets against their respective fair values. Based on the assessment, the Company recognized a loss on impairment of intangible assets in the amount of $463.7 million and $1.7 million in fixed assets recorded within Loss on Impairment of Assets within the Consolidated Statements of Operations. Since the study did not meet the primary and secondary endpoints, the Company has concluded that they will not make the potential milestone payments indicated in the Asset Purchase Agreement to the former Scioderm holders. Accordingly, the Company recognized a gain of $254.7 million in Changes in Fair Value of Contingent Consideration Payable in the third quarter of 2017, in order to decrease the liability to zero. The Company also recognized $0.4 million in selling, general and administrative costs and $8.1 million in research and development expenses related to the wind-down of operations for the Phase 3 ESSENCE study and ongoing extension studies SD-004 and SD-006, as well as income tax benefit of $164.7 million due to the reduction of the deferred tax liability related to Scioderm IPR&D, in the Consolidated Statements of Operations in the third quarter of 2017. See "— Note 4. Goodwill and IPR&D" for more details.

On February 15, 2018, the Company announced the pricing of an underwritten offering of 19,354,839 shares of its common stock at $15.50 per shares, resulting in gross proceeds of $300.0 million, before deducting underwriting discounts and commissions and offering expenses payable by the Company. The offering closed on February 21, 2018 and the Company received net proceeds of $282.0 million from the Offering, after deducting underwriting discounts and commissions and offering expenses payable by the Company. J.P. Morgan Securities LLC and Goldman Sachs & Co. LLC were acting as joint lead book-running managers, Cowen and Leerink Partners were acting as co-book-running managers, and BofA Merrill Lynch was acting as lead co-manager for the offering. The Company expects to use the net proceeds of the offering for investment in the U.S. and international commercial infrastructure for migalastat HCl, investment in manufacturing capabilities for ATB200, the continued clinical development of its product candidates, research and development expenditures, clinical and pre-clinical trial expenditures, commercialization expenditures and for other general corporate purposes.

In July 2017, the Company entered into an underwriting agreement ("the Underwriting Agreement") with J.P. Morgan Securities LLC and Goldman Sachs & Co. LLC, as representatives of the several underwriters set forth on Schedule 1 thereto, relating to an underwritten public offering of the Company's common stock (the "Offering"). Under the terms of the Underwriting Agreement, the Company issued and sold 21,122,449 shares at a price to the public of $12.25 per share, resulting in gross proceeds of $258.8 million, before deducting underwriting discounts and commissions and offering expenses payable by the Company. The Offering closed on July 18, 2017 and the Company received net proceeds from the Offering, after deducting underwriting discounts and commissions and offering expenses payable by the Company of $243.0 million. See "— Note 9. Equity" for more details.

In December 2016, the Company issued $250 million aggregate principal amount of 3.00% unsecured Convertible Senior Notes due 2023 (the "Convertible Notes"), in a private offering to qualified institutional buyers pursuant to Rule 144A under the Securities Act of 1933, as amended (the "Securities Act"). Interest is payable semiannually on June 15 and December 15 of each year, beginning on June 15, 2017. The Notes will mature on December 15, 2023, unless earlier repurchased, redeemed, or converted in accordance with their terms. The Notes are convertible at the option of the holders, under certain circumstances and during certain periods, into cash, shares of the Company's common stock, par value $0.01 per share ("Common Stock"), or a combination thereof. The net proceeds from the issuance of the Convertible Note offering were $243.0 million, after deducting fees and estimated expenses payable by the Company. In addition, the Company used approximately $13.5 million of the net proceeds from the issuance of the Convertible Notes to pay the cost of the capped call transactions ("Capped Call Confirmations") that the Company entered into in connection with the issuance of the Convertible Notes. For additional information, see "— Note 11. Debt Instruments and Related Party Transactions."

In July 2016, the Company expanded its biologics pipeline with a new preclinical program for CDKL5 deficiency, a rare and devastating genetic neurological disease for which there is no currently approved treatment. The Company has obtained the rights and related intellectual property to a preclinical CDKL5 program through its acquisition of MiaMed, Inc. ("MiaMed"). The aggregate value of the deal was approximately $89.5 million, which included an upfront payment of $6.5 million and Company stock, cash and potential milestones of up to $83.0 million. For additional information, see "— Note 3. Acquisitions".

Beginning in April 2016 and through July 2016, the Company sold 15.0 million shares of Common Stock under an at-the-market ("ATM") equity program with Cowen and Company, LLC ("Cowen") acting as sales agent. Cowen was compensated at a fixed commission rate up to 3.0%. The ATM sales agreement resulted in net proceeds of $97.1 million, after Cowen's commission of $2.7 million and other expenses of $0.2 million. The Company has completed all sales under the ATM equity program.

The Company had an accumulated deficit of approximately $1.1 billion at December 31, 2017 and anticipates incurring losses through the fiscal year ending December 31, 2018 and beyond. The Company has been able to fund its operating losses to date through stock offering, debt issuances, and payments from partners during the terms of the collaboration agreements and other financing arrangements.

The current cash position, including proceeds from the recent equity offering and expected Galafold revenues, is sufficient to fund ongoing Fabry and Pompe program operations into at least 2021. Potential future business development collaborations, pipeline expansion, and investment in biologics manufacturing capabilities could impact the Company's future capital requirements.