(Loss) Earnings per Share (Tables)

6 Months Ended

Jun. 30, 2014

Earnings Per Share [Abstract]

Schedule of Earnings Per Share, Basic and Diluted

The following table sets forth the computation of basic and diluted (loss) earnings per share for the three and six months ended June 30, 2014 and 2013:

	Three Months Ended June 30,					Six Months Ended June 30,
	2014			2013		2014			2013
	(in thousands, except per share amounts)
Basic and diluted
Net (loss) income attributable to The Medicines Company	$	(5,157	)	$	18,094	$	(10,153	)	$	6,521
Weighted average common shares outstanding, basic	64,400			55,553		64,277			54,804
Plus: net effect of dilutive stock options, restricted common shares and shares issuable upon conversion of Notes	—			4,708		—			4,350
Weighted average common shares outstanding, diluted	64,400			60,261		64,277			59,154
(Loss) income per share attributable to The Medicines Company, basic	$	(0.08	)	$	0.33	$	(0.16	)	$	0.12
(Loss) income per share attributable to The Medicines Company, diluted	$	(0.08	)	$	0.30	$	(0.16	)	$	0.11