Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 228,391	$ 519,446
Available for sale securities	23,692	50,875
Accrued interest receivable	150	348
Accounts receivable, net of allowances of approximately $23.9 million and $17.7 million at March 31, 2013 and December 31, 2012, respectively	90,435	85,893
Inventory	84,266	76,355
Deferred tax assets	13,881	13,881
Prepaid expenses and other current assets	18,828	9,577
Total current assets	459,643	756,375
Fixed assets, net	22,666	16,100
Intangible assets, net	458,531	119,576
Goodwill	144,262	14,671
Restricted cash	1,575	1,571
Deferred tax assets, net	0	46,625
Other assets	17,844	17,264
Total assets	1,104,521	972,182
Current liabilities:
Accounts payable	10,078	25,378
Accrued expenses	104,472	107,453
Deferred revenue	1,221	2,375
Total current liabilities	115,771	135,206
Contingent purchase price	105,807	18,971
Deferred tax liabilities	36,247	0
Convertible senior notes (due 2017)	228,555	226,109
Other liabilities	5,767	5,674
Total liabilities	492,147	385,960
Stockholders' equity:
Preferred stock, $1.00 par value per share, 5,000,000 shares authorized; no shares issued and outstanding	0	0
Common stock, $0.001 par value per share, 125,000,000 shares authorized; 57,840,183 issued and 55,647,201 outstanding at March 31, 2013 and 56,153,140 issued and 53,960,158 outstanding at December 31, 2012, respectively	57	56
Additional paid-in capital	735,420	697,427
Treasury stock, at cost; 2,192,982 shares at March 31, 2013 and December 31, 2012, respectively	(50,000)	(50,000)
Accumulated deficit	(71,984)	(60,411)
Accumulated other comprehensive loss	(1,002)	(766)
Total The Medicines Company stockholders' equity	612,491	586,306
Non-controlling interest in joint venture	(117)	(84)
Total stockholders' equity	612,374	586,222
Total liabilities and stockholders' equity	$ 1,104,521	$ 972,182