Financing	6 Months Ended
Jun. 30, 2018
Stockholders' Equity Note [Abstract]
Financing	9. Financing *Public Offering* On May 7, 2018, the Company closed an underwritten public offering (the “Offering”) in which it issued and sold (i) 4,875,000 shares of common stock together with a number of common warrants to purchase 2,437,500 shares of its common stock, and (ii) 9,500,000 pre-funded warrants, with each pre-funded warrant exercisable for one share of common stock, together with a number of common warrants to purchase 4,750,000 shares of its common stock. The public offering price was $1.44 per share of common stock, $1.43 per pre-funded warrant and $0.01 per common warrant. The net proceeds to the Company were approximately $18.8 million, net of underwriting discounts and commissions and other estimated offering expenses. The common stock warrants expire five years after date of issuance and have an exercise price of $1.584 per share. As of June 30, 2018, 3,054,667 common stock warrants have been exercised for an additional $4.8 million of proceeds to the Company and all pre-funded warrants have been exercised. In connection with the offering the Company entered into an underwriting agreement (the “Underwriting Agreement”), dated May 2, 2018 with A.G.P./Alliance Global Partners (A.G.P.), as representative of the underwriters. The Underwriting Agreement contains customary representations, warranties, and agreements by the Company, customary conditions to closing, indemnification obligations of the Company and the Underwriters, including for liabilities under the Securities Act of 1933, as amended (the “Securities Act”), other obligations of the parties and termination provisions. *At the Market Offering* On January 18, 2018, the Company entered into a Common Stock Sales Agreement with H.C. Wainwright & Co., LLC, (“HCW”) as sales agent, pursuant to which the Company may sell from time to time, at its option, shares of its common stock, par value $0.0002 per share for the sale of up to $3,658,000 of shares of the Company’s common stock and on March 15, 2018 issued a prospectus supplement for an additional aggregate offering price of up to $1,300,000. Sales of shares of common stock have been made pursuant to the Company’s shelf registration statement on Form S-3 (File No. 333-221201) filed with the U.S. Securities and Exchange Commission (“SEC”), dated November 13, 2017. As of June 30, 2018 the Company sold an aggregate of 1,403,367 shares of common stock under the HCW Sales Agreement resulting in net proceeds of approximately $3.4 million. *Common Stock Warrants* In connection with the May 7, 2018 public offering, the Company issued 9,500,000 pre-funded warrants and 7,187,500 common stock warrants each of which are exercisable for one share of common stock. The pre-funded warrants had an exercise price of $0.01 per share and as of June 30, 2018 all pre-funded warrants have been exercised. The common stock warrants have an exercise price of $1.584 per share and expire five years from the issuance date. As of June 30, 2018, 3,054,667 common stock warrants have been exercised. The warrants have been accounted for as equity instruments. The fair value of the common stock warrants of approximately $7.8 million at the date of issuance was estimated using the Black-Scholes Merton model which used the following inputs: term of 5 years, risk free rate of 2.78%, 0% dividend yield, volatility of 124.14%, and share price of $1.30 per share based on the trading price of the Company’s common stock. In connection with the March 23, 2017 public offering the Company issued warrants to purchase 682,500 shares of common stock with an exercise price of $10.00 per share that expire five years from the issuance date. In connection with the Company’s July 23, 2013 initial public offering, the Company issued warrants to the underwriters for 12,500 shares of common stock issuable at $125.00 per share upon exercise that expire five years from the issuance date. On March 10, 2011, the Company issued warrants to purchase shares of common stock to third parties in consideration for a private equity placement transaction of which 1,738 warrants remain outstanding. The warrants have an exercise price of $4.80 per share and expire ten years from the issuance date. During the six months ended June 30, 2018, 3,054,667 common stock warrants have been exercised and no warrants were exercised during the same period in 2017. The Company has outstanding warrants to purchase 4,132,833 shares of common stock issuable at $1.584 per share, 296,159 shares of common stock issuable at $10.00 per share; warrants to purchase 12,500 shares of common stock issuable at $125.00 per share; and warrants to purchase 1,738 shares of common stock issuable at $4.80 per share. These warrants do not meet the criteria required to be classified as liability awards and therefore are treated as equity awards.

Financing

6 Months Ended

Jun. 30, 2018

Stockholders' Equity Note [Abstract]

9. Financing

Public Offering

On May 7, 2018, the Company closed an underwritten public offering (the “Offering”) in which it issued and sold (i) 4,875,000 shares of common stock together with a number of common warrants to purchase 2,437,500 shares of its common stock, and (ii) 9,500,000 pre-funded warrants, with each pre-funded warrant exercisable for one share of common stock, together with a number of common warrants to purchase 4,750,000 shares of its common stock. The public offering price was $1.44 per share of common stock, $1.43 per pre-funded warrant and $0.01 per common warrant. The net proceeds to the Company were approximately $18.8 million, net of underwriting discounts and commissions and other estimated offering expenses. The common stock warrants expire five years after date of issuance and have an exercise price of $1.584 per share. As of June 30, 2018, 3,054,667 common stock warrants have been exercised for an additional $4.8 million of proceeds to the Company and all pre-funded warrants have been exercised. In connection with the offering the Company entered into an underwriting agreement (the “Underwriting Agreement”), dated May 2, 2018 with A.G.P./Alliance Global Partners (A.G.P.), as representative of the underwriters. The Underwriting Agreement contains customary representations, warranties, and agreements by the Company, customary conditions to closing, indemnification obligations of the Company and the Underwriters, including for liabilities under the Securities Act of 1933, as amended (the “Securities Act”), other obligations of the parties and termination provisions.

At the Market Offering

On January 18, 2018, the Company entered into a Common Stock Sales Agreement with H.C. Wainwright & Co., LLC, (“HCW”) as sales agent, pursuant to which the Company may sell from time to time, at its option, shares of its common stock, par value $0.0002 per share for the sale of up to $3,658,000 of shares of the Company’s common stock and on March 15, 2018 issued a prospectus supplement for an additional aggregate offering price of up to $1,300,000. Sales of shares of common stock have been made pursuant to the Company’s shelf registration statement on Form S-3 (File No. 333-221201) filed with the U.S. Securities and Exchange Commission (“SEC”), dated November 13, 2017. As of June 30, 2018 the Company sold an aggregate of 1,403,367 shares of common stock under the HCW Sales Agreement resulting in net proceeds of approximately $3.4 million.

Common Stock Warrants

In connection with the May 7, 2018 public offering, the Company issued 9,500,000 pre-funded warrants and 7,187,500 common stock warrants each of which are exercisable for one share of common stock. The pre-funded warrants had an exercise price of $0.01 per share and as of June 30, 2018 all pre-funded warrants have been exercised. The common stock warrants have an exercise price of $1.584 per share and expire five years from the issuance date. As of June 30, 2018, 3,054,667 common stock warrants have been exercised. The warrants have been accounted for as equity instruments. The fair value of the common stock warrants of approximately $7.8 million at the date of issuance was estimated using the Black-Scholes Merton model which used the following inputs: term of 5 years, risk free rate of 2.78%, 0% dividend yield, volatility of 124.14%, and share price of $1.30 per share based on the trading price of the Company’s common stock.

In connection with the March 23, 2017 public offering the Company issued warrants to purchase 682,500 shares of common stock with an exercise price of $10.00 per share that expire five years from the issuance date. In connection with the Company’s July 23, 2013 initial public offering, the Company issued warrants to the underwriters for 12,500 shares of common stock issuable at $125.00 per share upon exercise that expire five years from the issuance date. On March 10, 2011, the Company issued warrants to purchase shares of common stock to third parties in consideration for a private equity placement transaction of which 1,738 warrants remain outstanding. The warrants have an exercise price of $4.80 per share and expire ten years from the issuance date.

During the six months ended June 30, 2018, 3,054,667 common stock warrants have been exercised and no warrants were exercised during the same period in 2017. The Company has outstanding warrants to purchase 4,132,833 shares of common stock issuable at $1.584 per share, 296,159 shares of common stock issuable at $10.00 per share; warrants to purchase 12,500 shares of common stock issuable at $125.00 per share; and warrants to purchase 1,738 shares of common stock issuable at $4.80 per share. These warrants do not meet the criteria required to be classified as liability awards and therefore are treated as equity awards.