Subsequent Events - Schedule of Outstanding Common Stock (Details) (Parenthetical) - USD ($)					1 Months Ended	2 Months Ended	12 Months Ended
		Feb. 03, 2021	Apr. 12, 2019	Apr. 08, 2019	Jan. 31, 2021	Mar. 04, 2021	Dec. 31, 2019	Dec. 31, 2020	Jul. 28, 2020	Jun. 05, 2020	Mar. 27, 2019
Common stock purchase price per share										$ 0.45
Shares issued during the period new issue value							$ 6,335,000
Warrants exercise price								$ 1.82	$ 0.495
Common stock, par value							$ 0.0001	$ 0.0001		0.0001	$ 0.0001
Warrants to purchase								26,705,502	274,029
Maximum [Member]
Warrants exercise price									$ 2.25
Underwritten Public Offering [Member]
Common stock purchase price per share				$ 5.00
Number of stocks issued				486,957
Over-Allotment Option [Member]
Common stock purchase price per share			$ 5.00
Number of stocks issued			12,393
Common Stock [Member]
Number of stocks issued							3,039,161
Shares issued during the period new issue value	[1]
Series B Convertible Preferred Stock [Member]
Shares issued during the period new issue value
Series F Warrants [Member]
Common stock purchase price per share										0.45
Warrants exercise price								$ 0.50
Common stock, par value										$ 0.0001
Warrants to purchase								22,688,900		1
Subsequent Event [Member]
Investor agreed to invest		$ 900,000
Common stock purchase price per share		$ 0.6708
Sale of common stock					$ 323,000
Common stock, par value		0.0001
Subsequent Event [Member] | Underwriter [Member] | Maximum [Member]
Warrants exercise price		$ 0.682
Option to purchase up to additional units		4,354,838
Warrants to purchase		1,669,355
Subsequent Event [Member] | Underwritten Public Offering [Member] | Alliance Global Partners [Member]
Common stock purchase price per share		$ 0.62
Number of stocks issued		29,032,258
Warrants exercise price		$ 0.682
Common stock, par value		$ 0.0001
Subsequent Event [Member] | Over-Allotment Option [Member] | Underwriter [Member]
Net proceeds from exercise of warrants		$ 18,900,000
Subsequent Event [Member] | Common Stock [Member]
Number of stocks issued	[2]					33,387,096
Shares issued during the period new issue value	[2]					$ 20,700,000
Subsequent Event [Member] | Common Stock [Member] | Underwriter [Member]
Number of stocks issued		4,354,838
Subsequent Event [Member] | Series B Convertible Preferred Stock [Member]
Shares of common stock issued		17,303
Option to purchase up to additional units		3,112,923
Subsequent Event [Member] | Series F Warrants [Member]
Warrants exercise price		$ 0.495
Subsequent Event [Member] | Series G Warrants [Member]
Warrants exercise price		$ 0.682
Subsequent Event [Member] | Series G Warrants [Member] | Underwriter [Member]
Warrants to purchase		2,177,419
Subsequent Event [Member] | Series F and Series G Warrants [Member]
Net proceeds from exercise of warrants		$ 9,469,000
Subsequent Event [Member] | Series F and Series G Warrants [Member] | Common Stock [Member]
Number of stocks issued		18,381,177
Subsequent Event [Member] | ATM Sales Agreement [Member]
Number of stocks issued		12,277,844
Shares issued during the period new issue value		$ 5,659,000

[1] Represents an amount less than $1

[2] On February 3, 2021, the Company entered into an underwriting agreement with A.G.P./Alliance Global Partners, relating to an underwritten public offering (the "Offering") of 29,032,258 units ("Units"), with each Unit being comprised of one share of the Company's common stock, par value $0.0001 per share, and one Series G warrant to purchase one-half of one share of Common Stock. The offering price to the public was $0.62 per Unit. The Series G Warrants are immediately exercisable at a price of $0.682 per share, subject to adjustment in certain circumstances, and expire five years from the date of issuance. The Offering closed on February 8, 2021. The Company granted the Underwriter a 45-day option to purchase up to an additional 4,354,838 Units consisting of 4,354,838 shares of Common Stock and Series G Warrants to purchase 2,177,419 shares of common stock in the Offering, which the Underwriter exercised in full on February 4, 2021. The Company granted the Underwriter a compensation warrant to purchase up to 1,669,355 shares of Common Stock. The Underwriter Warrants have an exercise price of $0.682 per share and are exercisable immediately and for five years from the date of effectiveness of the registration statement in connection with the Offering. The net proceeds to the Company from the Offering, after giving effect to the exercise of the Underwriter's over-allotment option, were approximately $18.9 million, after deducting underwriting discounts and commissions and payment of other estimated expenses associated with the Offering, but excluding the proceeds, if any, from the exercise of Series G Warrants sold in the Offering.