SUBSEQUENT EVENTS	12 Months Ended
Dec. 31, 2021
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	19. SUBSEQUENT EVENTS The Company has evaluated events subsequent to the date of the balance sheet through the date of the Financial Statements. In January 2022, the Company invested $250,000 in a company which uses next generation gene modulation tools providing services to the Huntsville operations. The funds are in the form of a senior convertible note that bears fixed interest and is classified as a short-term investment on the balance sheet. On January 10, 2022, the Company entered into a Securities Purchase Agreement (the “Preferred Stock Purchase Agreement”) with several institutional investors, pursuant to which the Company agreed to issue and sell, in concurrent registered direct offerings (the “Preferred Offerings”), (i) 50,000 shares of the Company’s Series A Convertible Redeemable Preferred Stock, par value $0.01 per share (the “Series A Preferred Stock”), and (ii) 50,000 shares of the Company’s Series B Convertible Redeemable Preferred Stock, par value $0.01 per share (the “Series B Preferred Stock” and together with the Series A Preferred Stock, the “Preferred Stock”), in each case at an offering price of $285 per share, representing a 5% original issue discount to the stated value of $300 per share, for gross proceeds of each Offering of $14.25 million, or approximately $28.50 million in the aggregate for the Offerings, before the deduction of the Placement Agent’s (as defined below) fee and offering expenses. The shares of Series A Preferred Stock will have a stated value of $300 per share and will be convertible, at a conversion price of $13.65 per share, into 1,098,901 shares of common stock (subject in certain circumstances to adjustments). The shares of Series B Preferred Stock will have a stated value of $300 per share and will be convertible, at a conversion price of $15.00 per share, into 1,000,000 shares of common stock (subject in certain circumstances to adjustments). The Series A Preferred Stock and the Series B Preferred Stock are being offered by the Company pursuant to a registration statement on Form S-3 (File No. 333-254515) (the “Registration Statement”) filed under the Securities Act of 1933, as amended (the “Securities Act”). The Purchase Agreement contains customary representations, warranties and agreements by the Company and customary conditions to closing. The closing of the Offerings occurred on January 13, 2022. On March 3, 2022, the Company redeemed for cash at a price equal to 105% of the $300 stated value per share all of its 50,000 outstanding shares of Series A Preferred Stock and its 50,000 outstanding Series B Preferred Stock. As a result, all shares of the Preferred Stock have been retired and are no longer outstanding and Celsion’s only class of outstanding stock is its common stock. Each share of common stock entitles the holder to one vote. On February 28, 2022, the Company effected a 15-for-1 reverse stock split of its common stock which was made effective for trading purposes as of the commencement of trading on March 1, 2022. As of that date, each 15 shares of issued and outstanding common stock and equivalents was consolidated into one share of common stock. All shares have been restated to reflect the effects of the 15-for-1 reverse stock split. In addition, at the market open on March 1, 2022, the Company’s common stock started trading under a new CUSIP number 15117N602 although the Company’s ticker symbol, CLSN, remained unchanged. See Note 10 to the Financial Statements. The reverse stock split was previously approved by the Company’s stockholders at the 2022 Special Meeting held on February 24, 2022, and the Company subsequently filed a Certificate of Amendment to its Certificate of Incorporation to effect the stock consolidation.

SUBSEQUENT EVENTS

12 Months Ended

Dec. 31, 2021

19. SUBSEQUENT EVENTS

The Company has evaluated events subsequent to the date of the balance sheet through the date of the Financial Statements.

In January 2022, the Company invested $250,000 in a company which uses next generation gene modulation tools providing services to the Huntsville operations. The funds are in the form of a senior convertible note that bears fixed interest and is classified as a short-term investment on the balance sheet.

On January 10, 2022, the Company entered into a Securities Purchase Agreement (the “Preferred Stock Purchase Agreement”) with several institutional investors, pursuant to which the Company agreed to issue and sell, in concurrent registered direct offerings (the “Preferred Offerings”), (i) 50,000 shares of the Company’s Series A Convertible Redeemable Preferred Stock, par value $0.01 per share (the “Series A Preferred Stock”), and (ii) 50,000 shares of the Company’s Series B Convertible Redeemable Preferred Stock, par value $0.01 per share (the “Series B Preferred Stock” and together with the Series A Preferred Stock, the “Preferred Stock”), in each case at an offering price of $285 per share, representing a 5% original issue discount to the stated value of $300 per share, for gross proceeds of each Offering of $14.25 million, or approximately $28.50 million in the aggregate for the Offerings, before the deduction of the Placement Agent’s (as defined below) fee and offering expenses. The shares of Series A Preferred Stock will have a stated value of $300 per share and will be convertible, at a conversion price of $13.65 per share, into 1,098,901 shares of common stock (subject in certain circumstances to adjustments). The shares of Series B Preferred Stock will have a stated value of $300 per share and will be convertible, at a conversion price of $15.00 per share, into 1,000,000 shares of common stock (subject in certain circumstances to adjustments). The Series A Preferred Stock and the Series B Preferred Stock are being offered by the Company pursuant to a registration statement on Form S-3 (File No. 333-254515) (the “Registration Statement”) filed under the Securities Act of 1933, as amended (the “Securities Act”). The Purchase Agreement contains customary representations, warranties and agreements by the Company and customary conditions to closing. The closing of the Offerings occurred on January 13, 2022.

On March 3, 2022, the Company redeemed for cash at a price equal to 105% of the $300 stated value per share all of its 50,000 outstanding shares of Series A Preferred Stock and its 50,000 outstanding Series B Preferred Stock. As a result, all shares of the Preferred Stock have been retired and are no longer outstanding and Celsion’s only class of outstanding stock is its common stock. Each share of common stock entitles the holder to one vote.

On February 28, 2022, the Company effected a 15-for-1 reverse stock split of its common stock which was made effective for trading purposes as of the commencement of trading on March 1, 2022. As of that date, each 15 shares of issued and outstanding common stock and equivalents was consolidated into one share of common stock. All shares have been restated to reflect the effects of the 15-for-1 reverse stock split. In addition, at the market open on March 1, 2022, the Company’s common stock started trading under a new CUSIP number 15117N602 although the Company’s ticker symbol, CLSN, remained unchanged. See Note 10 to the Financial Statements. The reverse stock split was previously approved by the Company’s stockholders at the 2022 Special Meeting held on February 24, 2022, and the Company subsequently filed a Certificate of Amendment to its Certificate of Incorporation to effect the stock consolidation.