Document and Entity Information - shares	6 Months Ended
	Mar. 31, 2020	May 01, 2020
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2020
Document Transition Report	false
Entity File Number	001-34033
Entity Registrant Name	DIGI INTERNATIONAL INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	41-1532464
Entity Address, Address Line One	9350 Excelsior Blvd.
Entity Address, Address Line Two	Suite 700
Entity Address, City or Town	Hopkins
Entity Address, State or Province	MN
Entity Address, Postal Zip Code	55343
City Area Code	952
Local Phone Number	912-3444
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		28,954,853
Entity Central Index Key	0000854775
Current Fiscal Year End Date	--09-30
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Amendment Flag	false
The Nasdaq Stock Market LLC
Entity Information [Line Items]
Title of 12(b) Security	Common Stock, par value $.01 per share
Trading Symbol	DGII
Security Exchange Name	NASDAQ