Description of Business	6 Months Ended
Description of Business	Jun. 30, 2020
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 and product candidates across a range of therapeutic areas. As of June 30, 2020, we marketed products that support the health of patients in the areas of hematology and maternal and women’s health, including Feraheme^®(ferumoxytol injection) for intravenous use, Makena^®(hydroxyprogesterone caproate injection) auto-injector and Vyleesi^®(bremelanotide injection). In addition to our approved products, our portfolio includes two product candidates, ciraparantag, which is being studied as an anticoagulant reversal agent and AMAG-423 (digoxin immune fab (ovine)), which is being studied for the treatment of severe preeclampsia (although we have suspended research and development efforts as discussed elsewhere in this report). In December 2019, we completed a review of our product portfolio and strategy. This strategic review resulted in our intention to divest Intrarosa^® (prasterone) and Vyleesi^® (bremelanotide injection), as announced in January 2020. In May 2020, we completed the divestiture of Intrarosa, resulting in a gain on sale of $14.4 million recognized during the three and six months ended June 30, 2020. We determined that the divestiture of Intrarosa did not meet the criteria for presentation as a discontinued operation, as it did not represent a strategic shift to our business as described above. Additionally, we determined that the anticipated divestiture of Vyleesi did not result in the related assets meeting the criteria to be recorded as held for sale at June 30, 2020. In July 2020, we completed the divestiture of Vyleesi and decided to stop the AMAG-423 Phase 2b/3a study based, primarily, on the results of an interim analysis conducted by the study’s independent Data Safety Monitoring Board (“DSMB”). Refer to Note U, “Subsequent Events” for further detail. Throughout this Quarterly Report on Form 10-Q, AMAG Pharmaceuticals, Inc. and our consolidated subsidiaries are collectively referred to as “the Company,” “AMAG,” “we,” “us,” or “our.” COVID-19 The global spread of COVID-19 has created significant volatility, uncertainty and economic disruption on a global scale, including in the United States, where we market our products, where our operations and employees reside and where we conduct clinical trials, as well as in Europe and other countries where we have been conducting our AMAG-423 Phase 2b/3a study. The COVID-19 pandemic negatively impacted our financial results during the three months ended June 30, 2020 and is expected to continue to negatively impact our financial results in future periods in 2020. The extent to which the COVID-19 pandemic impacts our business, operations and financial results will depend on numerous evolving factors that we may not be able to accurately predict. While there have been no material impairments to date, any prolonged material disruptions to our sales, supply, research and development efforts and/or operations could negatively impact the Company’s business, operations and/or financial results.