Shelf Registration Statement	12 Months Ended
Dec. 31, 2018
Stock Offering [Abstract]
Shelf Registration Statement	Shelf Registration Statements On November 9, 2017, the Company filed a shelf registration statement on Form S-3 with the SEC to, from time to time, sell up to an aggregate of $125 million of any combination of its common stock, warrants, debt securities or units. On November 16, 2017, the registration statement was declared effective by the SEC, which will allow the Company to access the capital markets for the three-year period following this effective date. Net proceeds, terms and pricing of each offering of securities issued under the shelf registration statement will be determined at the time of such offerings. In August 2018, under the shelf registration statement, the Company completed a public offering of 7,590,000 shares of its common stock at a public offering price of $3.25 per share. The Company received total net proceeds of approximately $23.0 million from the offering, after deducting underwriting discounts, commissions and offering expenses. Offering net proceeds are being used for general corporate purposes, including research and development expenses, capital expenditures, working capital, repayment of debt and general and administrative expenses. As of December 31, 2018, $24.7 million of securities have been issued under the shelf registration statement and a balance of $100.3 million remains available for future issuance.

Shelf Registration Statements

On November 9, 2017, the Company filed a shelf registration statement on Form S-3 with the SEC to, from time to time, sell up to an aggregate of $125 million of any combination of its common stock, warrants, debt securities or units. On November 16, 2017, the registration statement was declared effective by the SEC, which will allow the Company to access the capital markets for the three-year period following this effective date. Net proceeds, terms and pricing of each offering of securities issued under the shelf registration statement will be determined at the time of such offerings.

In August 2018, under the shelf registration statement, the Company completed a public offering of 7,590,000 shares of its common stock at a public offering price of $3.25 per share. The Company received total net proceeds of approximately $23.0 million from the offering, after deducting underwriting discounts, commissions and offering expenses. Offering net proceeds are being used for general corporate purposes, including research and development expenses, capital expenditures, working capital, repayment of debt and general and administrative expenses. As of December 31, 2018, $24.7 million of securities have been issued under the shelf registration statement and a balance of $100.3 million remains available for future issuance.