Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended								12 Months Ended
	Dec. 31, 2016	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jun. 30, 2012
Amounts attributable to The Medicines Company:
Net (loss) income from continuing operations		$ (124,428)	$ (86,354)	$ 181,823	$ (90,343)	$ (68,241)	$ (90,617)	$ (67,445)	$ 4,373	$ (119,302)	$ (221,930)	$ 319
Income (loss) from discontinued operations, net of tax		1,574	96	619	(2,105)	(137,825)	(14,515)	20,853	661	184	(130,826)	(32,529)
Net loss attributable to The Medicines Company		$ (122,854)	$ (86,258)	$ 182,442	$ (92,448)	$ (206,066)	$ (105,132)	$ (46,592)	$ 5,034	$ (119,118)	$ (352,756)	$ (32,210)
Weighted average common shares outstanding, basic (shares)										69,909,000	66,809,000	64,473,000
Plus: net effect of dilutive stock options, warrants, restricted common shares and shares issuable upon conversion of Notes (shares)										0	0	2,195,000
Weighted average common shares outstanding, diluted (shares)										69,909,000	66,809,000	66,668,000
Basic (loss) income per common share attributable to The Medicines Company:
(Loss) income from continuing operations (usd per share)										$ (1.71)	$ (3.32)	$ 0.00
Income (loss) from discontinued operations (usd per share)										0.00	(1.96)	(0.50)
Basic loss per share (usd per share)										(1.71)	(5.28)	(0.50)
Diluted (loss) income per common share attributable to The Medicines Company:
(Loss) income from continuing operations (usd per share)		$ (1.77)	$ (1.23)	$ 2.51	$ (1.31)	$ (0.99)	$ (1.35)	$ (1.02)	$ 0.07	(1.71)	(3.32)	0.00
Income (loss) from discontinued operations (usd per share)		0.02	0.00	0.01	(0.03)	(2.00)	(0.22)	0.31	0.01	0.00	(1.96)	(0.49)
Diluted loss per share (usd per share)		$ (1.75)	$ (1.23)	$ 2.52	$ (1.34)	$ (2.99)	$ (1.57)	$ (0.71)	$ 0.08	$ (1.71)	$ (5.28)	$ (0.49)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares excluded from computation of earnings per share (in shares)										3,112,627	3,724,272
2017 Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares exercisable upon conversion													2,000,000
Exercise price of warrants (usd per share)													$ 34.20
Restricted stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares excluded from computation of earnings per share (in shares)												3,915,906
Convertible Senior Notes Due 2023 [Member] | Senior Notes [Member] | Capped call [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Strike price, capped calls (usd per share)	$ 48.97
Cap price (usd per share)	$ 64.68
Convertible Senior Notes Due 2017 [Member] | Senior Notes [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Debt, aggregate principal amount repurchased				$ 220,000