Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2020	Mar. 26, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Registrant Name	OPGEN INC
Entity Central Index Key	0001293818
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Filer Category	Non-accelerated Filer
Entity Public Float			$ 35,998,374
Entity Common Stock, Shares Outstanding		38,266,482
Entity Interactive Data Current	Yes
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	06-1614015
Entity File Number	001-37367
Entity Address, Address Line One	708 Quince Orchard Road
Entity Address, City or Town	Gaithersburg
Entity Address, State or Province	MD
Entity Address, Postal Zip Code	20878
City Area Code	240
Local Phone Number	813-1260
Document Annual Report	true
Document Transition Report	false
Documents Incorporated by Reference	Portions of the registrant's definitive Proxy Statement to be filed with respect to its 2021 Annual Meeting of Stockholders are incorporated herein by reference in Part III of this Annual Report on Form 10-K to the extent stated herein. The proxy statement will be filed with the Securities and Exchange Commission within 120 days after the registrant's fiscal year ended December 31, 2020.