Note 8 - Fair Value of Consideration (Details) - USD ($)		1 Months Ended	3 Months Ended		12 Months Ended
	Jun. 20, 2014	Jun. 20, 2014	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014
EGEN Inc [Member]
Cash, net of cash acquired		$ 2,821,000
Celsion common stock (2,712,188 shares valued at $3.48 which was the last closing price of our common stock at the time of closing the transaction on June 20, 2014)		9,438,000
Holdback Shares (670,070 shares of Celsion common stock which were discounted by 38% to reflect the cost of the restriction)		1,441,000
Business Combination, Consideration Transferred, Liabilities Incurred	$ 13,900,000	13,878,000	$ 14,200,000	$ 13,800,000	$ 13,900,000	$ 13,700,000
Business Combination, Consideration Transferred	$ 27,600,000	$ 27,578,000
Business Combination, Consideration Transferred, Liabilities Incurred			$ 302,656	$ 13,800,000		$ 13,700,000