Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net loss	$ (708,373)	$ (119,172)	$ (352,746)
Other comprehensive income (loss):
Foreign currency translation adjustment	296	213	1,445
Amounts reclassified from accumulated other comprehensive income	0	(9,665)	0
Other comprehensive income (loss)	296	(9,452)	1,445
Comprehensive loss	(708,077)	(128,624)	(351,301)
Less: comprehensive loss (income) attributable to non-controlling interest	0	54	(10)
Comprehensive loss attributable to The Medicines Company	$ (708,077)	$ (128,570)	$ (351,311)