Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2021	May 14, 2021
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Entity Registrant Name	OPGEN INC
Entity Central Index Key	0001293818
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Incorporation, State or Country Code	DE
Entity Interactive Data Current	Yes
Entity Small Business	true
Entity Emerging Growth Company	false
Entity File Number	001-37367
Entity Common Stock, Shares Outstanding		38,266,482
Entity Current Reporting Status	Yes
Entity Shell Company	false