Document and Entity Information	6 Months Ended
	Jun. 30, 2013	Jul. 31, 2013
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2013
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q2
Trading Symbol	ARIA
Entity Registrant Name	ARIAD PHARMACEUTICALS INC
Entity Central Index Key	0000884731
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		185,106,733