Document And Entity Information - shares	9 Months Ended
	Sep. 30, 2021	Nov. 11, 2021
Cover [Abstract]
Document Type	10-Q
Entity Central Index Key	0001293818
Document Period End Date	Sep. 30, 2021
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Amendment Flag	false
Document Quarterly Report	true
Document Transition Report	false
Entity File Number	001-37367
Entity Registrant Name	OPGEN, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	06-1614015
Entity Address, Address Line One	9717 Key West Avenue
Entity Address, Address Line Two	Suite 100
Entity Address, City or Town	Rockville
Entity Address, State or Province	MD
Entity Address, Postal Zip Code	20850
City Area Code	240
Local Phone Number	813-1260
Title of 12(b) Security	Common Stock
Trading Symbol	OPGN
Name of Exchange on which Security is Registered	NASDAQ
Entity Information, Former Legal or Registered Name	N/A
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		38,950,250