Stockholders' Equity	3 Months Ended
Mar. 31, 2019
Equity [Abstract]
Stockholders' Equity	7. Stockholders’ Equity Underwritten Offerings In January 2019, the Company completed underwritten public offerings of (i) 23,000,000 shares of its common stock at a price to the public of $0.50 for each share of common stock, and (ii) 17,000 shares of its non-voting Series E Convertible Preferred Stock (“Series E Stock”) at a price to the public of $500 for each share of Series E Stock. Gross proceeds from the sale were $20.0 million and net proceeds were approximately $18.6 million. Each share of non-voting Series E Stock is convertible into 1,000 shares of the Company’s common stock, provided that conversion will be prohibited if, as a result, the holder and its affiliates would own more than 9.98% of the total number of shares of the Company’s common stock then outstanding; provided, however, that a holder may, upon written notice, elect to increase or decrease this percentage (not to exceed the limits under Nasdaq Marketplace Rule 5635(b), to the extent applicable). During the three months ended March 31, 2019, 7,000 shares of Series E Stock were converted into 7,000,000 shares of common stock with the remaining 10,000 shares of Series E Stock outstanding as of March 31, 2019. Controlled Equity Offerings Cantor Controlled Equity Offering During the three months ended March 31, 2019, no shares of common stock were sold under the Controlled Equity Offering^SM sales agreement, as amended (the “Sales Agreement”), with Cantor Fitzgerald & Co. (“Cantor”), as agent and/or principal. As of March 31, 2019, $43.6 million of common stock remained available to be sold under this facility, subject to certain conditions as specified in the Sales Agreement. Aspire Common Stock Purchase Agreement During the three months ended March 31, 2019, no shares were issued under the Common Stock Purchase Agreement (the “CSPA”) with Aspire Capital Fund, LLC (“Aspire”). Aspire’s remaining purchase commitment was $10.9 million as of March 31, 2019.

Stockholders' Equity

3 Months Ended

Mar. 31, 2019

7. Stockholders’ Equity

Underwritten Offerings

In January 2019, the Company completed underwritten public offerings of (i) 23,000,000 shares of its common stock at a price to the public of $0.50 for each share of common stock, and (ii) 17,000 shares of its non-voting Series E Convertible Preferred Stock (“Series E Stock”) at a price to the public of $500 for each share of Series E Stock. Gross proceeds from the sale were $20.0 million and net proceeds were approximately $18.6 million. Each share of non-voting Series E Stock is convertible into 1,000 shares of the Company’s common stock, provided that conversion will be prohibited if, as a result, the holder and its affiliates would own more than 9.98% of the total number of shares of the Company’s common stock then outstanding; provided, however, that a holder may, upon written notice, elect to increase or decrease this percentage (not to exceed the limits under Nasdaq Marketplace Rule 5635(b), to the extent applicable). During the three months ended March 31, 2019, 7,000 shares of Series E Stock were converted into 7,000,000 shares of common stock with the remaining 10,000 shares of Series E Stock outstanding as of March 31, 2019.

Controlled Equity Offerings

Cantor Controlled Equity Offering

During the three months ended March 31, 2019, no shares of common stock were sold under the Controlled Equity Offering^SM sales agreement, as amended (the “Sales Agreement”), with Cantor Fitzgerald & Co. (“Cantor”), as agent and/or principal. As of March 31, 2019, $43.6 million of common stock remained available to be sold under this facility, subject to certain conditions as specified in the Sales Agreement.

Aspire Common Stock Purchase Agreement

During the three months ended March 31, 2019, no shares were issued under the Common Stock Purchase Agreement (the “CSPA”) with Aspire Capital Fund, LLC (“Aspire”). Aspire’s remaining purchase commitment was $10.9 million as of March 31, 2019.