Note 14 - Celsion Employee Benefit Plans (Details Textual)	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Minimum Age For Employee Benefit Plan	21
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	3.00%
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 77,352	$ 82,391
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 172,497
Defined Contribution Plan, Employer Discretionary Contribution Percent	6.00%