Document and Entity Information - shares	9 Months Ended
	Jun. 30, 2019	Jul. 30, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Trading Symbol	SRDX
Entity Registrant Name	SURMODICS INC
Entity Central Index Key	0000924717
Current Fiscal Year End Date	--09-30
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		13,490,598
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity File Number	0-23837
Entity Tax Identification Number	411356149
Entity Address, Address Line One	9924 West 74th Street
Entity Address, City or Town	Eden Prairie
Entity Address, State or Province	Minnesota
Entity Address, Postal Zip Code	55344
City Area Code	952
Local Phone Number	500-7000