Document and Entity Information	9 Months Ended
	Dec. 31, 2012	Jan. 31, 2013
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Dec. 31, 2012
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q3
Trading Symbol	ABMD
Entity Registrant Name	ABIOMED INC
Entity Central Index Key	0000815094
Current Fiscal Year End Date	--03-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		38,557,806