Subsequent Events	12 Months Ended
Dec. 31, 2019
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On March 4, 2020, the Company entered into a securities purchase agreement with certain institutional investors for the issuance and sale in a registered direct offering of (i) 11,903,506 shares of the Company’s common stock and (ii) warrants to purchase up to a total of 11,903,506 shares of common stock at an offering price of $0.9275 per share and accompanying warrant. The aggregate net proceeds from the offering were approximately $10.2 million, excluding exercise of any warrants issued in the offering and after deducting the placement agent fees and estimated offering expenses. On February 14, 2020, the Company closed an underwriting agreement with H.C. Wainwright & Co. for the issuance and sale of (i) 10,146,154 Class A Units, each consisting of one share of common stock and one Series C Warrant to purchase one share of common stock, at a public offering price of $0.65 per Class A Unit, and (ii) 2,161,539 Class B Units, each consisting of one Series D Pre-Funded Warrant to purchase one share of common stock and one Series C Warrant to purchase one share of common stock, at a public offering price of $0.6499 per Class B Unit. The Series C Warrants have an exercise price of $0.65 per share, are immediately exercisable and will expire five years from the date of issuance. The Company granted the underwriter a 30-day option to purchase up to an additional 1,846,153 shares of common stock and/or additional Series C Warrants to purchase up to 1,846,153 shares of common stock. The underwriter fully exercised its option to purchase the shares and the Series C Warrants. The aggregate net proceeds from the offering were $8.3 million after deducting underwriting commissions and estimated offering expenses. As of March 6, 2020, 2,633,500 shares of common stock have been issued pursuant to the exercise of the Series C Warrants at an exercise price of $0.65 per share for aggregate net proceeds of approximately $1.7 million. During the period from January 1, 2020 through March 4, 2020, the Company issued and sold 2,151,346 shares at an average price of $1.30 per share under the ATM program. The net proceeds were approximately $2.7 million after BTIG's commission of $0.1 million and other offering expenses. On March 4, 2020, the Company delivered notice of termination of the sales agreement to BTIG. The Company will not incur any termination penalties as a result of its termination of the sales agreement.

Subsequent Events

On March 4, 2020, the Company entered into a securities purchase agreement with certain institutional investors for the issuance and sale in a registered direct offering of (i) 11,903,506 shares of the Company’s common stock and (ii) warrants to purchase up to a total of 11,903,506 shares of common stock at an offering price of $0.9275 per share and accompanying warrant. The aggregate net proceeds from the offering were approximately $10.2 million, excluding exercise of any warrants issued in the offering and after deducting the placement agent fees and estimated offering expenses.

On February 14, 2020, the Company closed an underwriting agreement with H.C. Wainwright & Co. for the issuance and sale of (i) 10,146,154 Class A Units, each consisting of one share of common stock and one Series C Warrant to purchase one share of common stock, at a public offering price of $0.65 per Class A Unit, and (ii) 2,161,539 Class B Units, each consisting of one Series D Pre-Funded Warrant to purchase one share of common stock and one Series C Warrant to purchase one share of common stock, at a public offering price of $0.6499 per Class B Unit. The Series C Warrants have an exercise price of $0.65 per share, are immediately exercisable and will expire five years from the date of issuance. The Company granted the underwriter a 30-day option to purchase up to an additional 1,846,153 shares of common stock and/or additional Series C Warrants to purchase up to 1,846,153 shares of common stock. The underwriter fully exercised its option to purchase the shares and the Series C Warrants. The aggregate net proceeds from the offering were $8.3 million after deducting underwriting commissions and estimated offering expenses. As of March 6, 2020, 2,633,500 shares of common stock have been issued pursuant to the exercise of the Series C Warrants at an exercise price of $0.65 per share for aggregate net proceeds of approximately $1.7 million.

During the period from January 1, 2020 through March 4, 2020, the Company issued and sold 2,151,346 shares at an average price of $1.30 per share under the ATM program. The net proceeds were approximately $2.7 million after BTIG's commission of $0.1 million and other offering expenses. On March 4, 2020, the Company delivered notice of termination of the sales agreement to BTIG. The Company will not incur any termination penalties as a result of its termination of the sales agreement.