Document And Entity Information - shares	9 Months Ended
	Jun. 30, 2015	Aug. 11, 2015
Entity Registrant Name	Bridgeline Digital, Inc.
Entity Central Index Key	0001378590
Current Fiscal Year End Date	--09-30
Entity Filer Category	Smaller Reporting Company
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Entity Common Stock, Shares Outstanding (in shares)		4,441,381
Document Type	10-Q
Document Period End Date	Jun. 30, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q3
Amendment Flag	false