Description of Business	12 Months Ended
Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	DESCRIPTION OF BUSINESS AMAG Pharmaceuticals, Inc., a Delaware corporation, was founded in 1981. We are a pharmaceutical company focused on bringing innovative products to patients with unmet medical needs by leveraging our development and commercial expertise to invest in and grow our pharmaceutical products across a range of therapeutic areas. Our currently marketed products support the health of patients in the areas of maternal and women’s health, anemia management and cancer supportive care, including Feraheme^® (ferumoxytol injection) for intravenous use, Makena^® (hydroxyprogesterone caproate injection), Intrarosa^® (prasterone) vaginal inserts and MuGard^® Mucoadhesive Oral Wound Rinse. In addition to our marketed products, our portfolio includes three product candidates, Vyleesi™ (bremelanotide), which is being developed for the treatment of hypoactive sexual desire disorder (“HSDD”) in pre-menopausal women, AMAG-423 (digoxin immune fab (ovine)), which is being studied for the treatment of severe preeclampsia, and ciraparantag, which is being studied as an anticoagulant reversal agent. We acquired ciraparantag through our acquisition of Perosphere Pharmaceuticals Inc (“Perosphere”), which was completed on January 16, 2019. See Note W, “Subsequent Events” for further details on the Perosphere acquisition. On August 6, 2018, we completed the sale of our wholly-owned subsidiary, CBR Acquisition Holdings Corp, and the Cord Blood Registry^® (“CBR”) business to GI Partners (“GI”), a private equity investment firm, pursuant to the June 14, 2018 Stock Purchase Agreement between us and affiliates of GI. We received $519.3 million in cash at closing and recognized a gain of $87.1 million on the sale during the year ended December 31, 2018. Since August 2015, we had provided services related to the preservation of umbilical cord blood stem cell and cord tissue units operated through CBR. For additional information, see Note C, “Discontinued Operations and Held for Sale”. We are subject to risks common to companies in the pharmaceutical industry including, but not limited to (as such risks pertain to our business) our ability to successfully commercialize our products, intense competition, including from generic products; maintaining and defending the proprietary nature of our technology; our dependence upon third-party manufacturers and our potential inability to obtain raw or other materials and impacts of supply shortages; our reliance on and the extent of reimbursement from third parties for the use of our products, including the impact of generic competitors, Makena’s high Medicaid reimbursement concentration and the limited level of reimbursement for Intrarosa; our ability to expand our product portfolio through business development transactions; the approval of our product candidates and our ability to commercialize such products, if approved; employee retention and our ability to manage our expanded product portfolio; potential litigation, including securities and product liability suits; our ability to work effectively and collaboratively with our licensors and partners; our reliance on other third parties in our business, including to conduct our clinical trials and undertake our product and distribution; our ability to attract and retain key employees; our potential failure to comply with federal and state healthcare fraud and abuse laws, marketing disclosure laws, or other federal and state laws and regulations and potential civil or criminal penalties as a result thereof; uncertainties regarding reporting and payment obligations under government pricing programs; post-approval commitments for Makena and Feraheme; our ability to comply with data protection laws and regulations; the impact of disruptions to our information technology systems; our level of and ability to repay our indebtedness; our access to sufficient capital; the availability of net operating loss carryforwards and other tax assets; potential differences between actual future results and the estimates or assumptions used by us in preparation of our consolidated financial statements, including goodwill and intangible assets; the volatility of our stock price; the potential fluctuation of our operating results; and provisions in our charter, by-laws and certain contracts that discourage an acquisition of our company. Throughout this Annual Report on Form 10-K, AMAG Pharmaceuticals, Inc. and our consolidated subsidiaries are collectively referred to as “the Company,” “AMAG,” “we,” “us,” or “our.”

DESCRIPTION OF BUSINESS

AMAG Pharmaceuticals, Inc., a Delaware corporation, was founded in 1981. We are a pharmaceutical company focused on bringing innovative products to patients with unmet medical needs by leveraging our development and commercial expertise to invest in and grow our pharmaceutical products across a range of therapeutic areas. Our currently marketed products support the health of patients in the areas of maternal and women’s health, anemia management and cancer supportive care, including Feraheme^® (ferumoxytol injection) for intravenous use, Makena^® (hydroxyprogesterone caproate injection), Intrarosa^® (prasterone) vaginal inserts and MuGard^® Mucoadhesive Oral Wound Rinse. In addition to our marketed products, our portfolio includes three product candidates, Vyleesi™ (bremelanotide), which is being developed for the treatment of hypoactive sexual desire disorder (“HSDD”) in pre-menopausal women, AMAG-423 (digoxin immune fab (ovine)), which is being studied for the treatment of severe preeclampsia, and ciraparantag, which is being studied as an anticoagulant reversal agent.

We acquired ciraparantag through our acquisition of Perosphere Pharmaceuticals Inc (“Perosphere”), which was completed on January 16, 2019. See Note W, “Subsequent Events” for further details on the Perosphere acquisition.

On August 6, 2018, we completed the sale of our wholly-owned subsidiary, CBR Acquisition Holdings Corp, and the Cord Blood Registry^® (“CBR”) business to GI Partners (“GI”), a private equity investment firm, pursuant to the June 14, 2018 Stock Purchase Agreement between us and affiliates of GI. We received $519.3 million in cash at closing and recognized a gain of $87.1 million on the sale during the year ended December 31, 2018. Since August 2015, we had provided services related to the preservation of umbilical cord blood stem cell and cord tissue units operated through CBR. For additional information, see Note C, “Discontinued Operations and Held for Sale”.

We are subject to risks common to companies in the pharmaceutical industry including, but not limited to (as such risks pertain to our business) our ability to successfully commercialize our products, intense competition, including from generic products; maintaining and defending the proprietary nature of our technology; our dependence upon third-party manufacturers and our potential inability to obtain raw or other materials and impacts of supply shortages; our reliance on and the extent of reimbursement from third parties for the use of our products, including the impact of generic competitors, Makena’s high Medicaid reimbursement concentration and the limited level of reimbursement for Intrarosa; our ability to expand our product portfolio through business development transactions; the approval of our product candidates and our ability to commercialize such products, if approved; employee retention and our ability to manage our expanded product portfolio; potential litigation, including securities and product liability suits; our ability to work effectively and collaboratively with our licensors and partners; our reliance on other third parties in our business, including to conduct our clinical trials and undertake our product and distribution; our ability to attract and retain key employees; our potential failure to comply with federal and state healthcare fraud and abuse laws, marketing disclosure laws, or other federal and state laws and regulations and potential civil or criminal penalties as a result thereof; uncertainties regarding reporting and payment obligations under government pricing programs; post-approval commitments for Makena and Feraheme; our ability to comply with data protection laws and regulations; the impact of disruptions to our information technology systems; our level of and ability to repay our indebtedness; our access to sufficient capital; the availability of net operating loss carryforwards and other tax assets; potential differences between actual future results and the estimates or assumptions used by us in preparation of our consolidated financial statements, including goodwill and intangible assets; the volatility of our stock price; the potential fluctuation of our operating results; and provisions in our charter, by-laws and certain contracts that discourage an acquisition of our company.

Throughout this Annual Report on Form 10-K, AMAG Pharmaceuticals, Inc. and our consolidated subsidiaries are collectively referred to as “the Company,” “AMAG,” “we,” “us,” or “our.”