Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2019	Mar. 17, 2020	Jun. 28, 2019
Document Information [Line Items]
Entity Registrant Name	FALCONSTOR SOFTWARE INC
Entity Central Index Key	0000922521
Document Type	10-K
Document Period End Date	Dec. 31, 2019
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Interactive Data Current	Yes
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 3,382,281
Entity Common Stock, Shares Outstanding		5,919,295
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2019