Stockholders' Equity	3 Months Ended
Mar. 31, 2019
Equity [Abstract]
Stockholders' Equity	Note 10 — Stockholders' Equity Common Stock and Preferred Stock As of March 31, 2019, the Company is authorized to issue 200 million shares of common stock and has 10 million shares of authorized but unissued shares of preferred stock. Without any further vote or action by the Company's stockholders, the Board of Directors has the authority to determine the powers, preferences, rights, qualifications, limitations or restrictions granted to or imposed upon any wholly unissued shares of undesignated preferred stock. Issuance of Common Stock On March 15, 2019, the Company filed a shelf registration statement on Form S-3, under which the Company may, from time to time, sell securities on one or more offerings up to a total amount of $75 million. The Company’s shelf registration statement was declared effective on March 29, 2019. Under the shelf registration dated December 6, 2016, as amended on March 15, 2017, and on May 29, 2018, the Company issued an aggregate of 13.5 million shares of common stock, $0.001 par value and warrants to purchase up to an aggregate of 5.4 million shares of common stock in a confidentially marketed underwritten offering. The common stock and warrants were issued in units (the “Units”), with each Unit consisting of (i) one share of common stock and (ii) a warrant to purchase 0.40 of a share of common stock, at a price of $1.15 per Unit. The Company received total net proceeds from the offering of $13.9 million. The warrants are exercisable any time for a period of 60 months from the date of issuance on May 29, 2018, and are exercisable at a price of $1.38 per share. The Company allocated the proceeds between the common stock and the warrants based on the relative fair value of each on the date of issuance. The estimated grant date fair value was $0.57 per warrant and was calculated based on the following assumptions used in the Black-Scholes model: expected term of 5 years, risk-free interest rate of 2.58%, expected volatility of 52.75% and expected dividend of zero.

Stockholders' Equity

3 Months Ended

Mar. 31, 2019

Note 10 — Stockholders' Equity

Common Stock and Preferred Stock

As of March 31, 2019, the Company is authorized to issue 200 million shares of common stock and has 10 million shares of authorized but unissued shares of preferred stock. Without any further vote or action by the Company's stockholders, the Board of Directors has the authority to determine the powers, preferences, rights, qualifications, limitations or restrictions granted to or imposed upon any wholly unissued shares of undesignated preferred stock.

Issuance of Common Stock

On March 15, 2019, the Company filed a shelf registration statement on Form S-3, under which the Company may, from time to time, sell securities on one or more offerings up to a total amount of $75 million. The Company’s shelf registration statement was declared effective on March 29, 2019.

Under the shelf registration dated December 6, 2016, as amended on March 15, 2017, and on May 29, 2018, the Company issued an aggregate of 13.5 million shares of common stock, $0.001 par value and warrants to purchase up to an aggregate of 5.4 million shares of common stock in a confidentially marketed underwritten offering. The common stock and warrants were issued in units (the “Units”), with each Unit consisting of (i) one share of common stock and (ii) a warrant to purchase 0.40 of a share of common stock, at a price of $1.15 per Unit. The Company received total net proceeds from the offering of $13.9 million.

The warrants are exercisable any time for a period of 60 months from the date of issuance on May 29, 2018, and are exercisable at a price of $1.38 per share. The Company allocated the proceeds between the common stock and the warrants based on the relative fair value of each on the date of issuance. The estimated grant date fair value was $0.57 per warrant and was calculated based on the following assumptions used in the Black-Scholes model: expected term of 5 years, risk-free interest rate of 2.58%, expected volatility of 52.75% and expected dividend of zero.