Note 12. Stockholders’ Equity

Authorized Common Stock

In April 2017, the number of authorized shares of the Company's common stock was increased from 75,000,000 to 125,000,000, by vote of the holders of a majority of the outstanding shares of the Company's common stock.

Public Offerings and Outstanding Warrants

On May 3, 2017, the Company completed an underwritten public offering of (i) 12,000,000 shares of its common stock, (ii) Series C warrants to purchase 12,000,000 shares of its common stock and (iii) Series D warrants to purchase 12,000,000 shares of its common stock, for gross proceeds of approximately $15.4 million, at a public offering price of $1.28 per share and accompanying warrants. Total net proceeds to the Company were approximately $13.9 million. The Series C warrants have an exercise price of $1.60 per share and a term of five years. A total of 419,100 shares of common stock were issued during the fourth quarter of fiscal year 2017 upon the exercise of Series C warrants and the Company received total proceeds of $0.7 million. The Series D warrants have an exercise price of $1.28 per share and a term of one year. A total of 9,415,826 shares of common stock were issued during the third and fourth quarters of fiscal year 2017 upon the exercise of Series D warrants and the Company received total proceeds of $12.1 million.

On July 12, 2016, the Company closed on a registered public offering of securities to a single institutional investor pursuant to a placement agent agreement with J.P. Morgan Securities LLC. In conjunction with the offering the Company issued 7,680,000 Series A Warrants, all of which remained outstanding as of October 31, 2017, at an exercise price of $5.83 per share. They are initially exercisable beginning on the date that is six months and one day after the issue date and will expire on the fifth anniversary of the initial exercisability date. The Company also issued 4,926,000 prefunded Series B Warrants which are immediately exercisable. They have an exercise price of $0.0001 per share and will expire on the fifth anniversary of the issue date. There were 3,826,000 prefunded Series B Warrants outstanding as of October 31, 2016, all of which were exercised during the year ended October 31, 2017.

On July 30, 2014, the Company issued a warrant to NRG in conjunction with the entry into a Securities Purchase Agreement for the sale of common stock. Pursuant to the warrant agreement, NRG had the right to purchase up to 0.2 million shares of the Company’s common stock at an exercise price of $40.20 per share. The warrants expired on July 30, 2017.

The following table outlines the warrant activity during the year ended October 31, 2017:

	Series A Warrants		Series B Warrants			Series C Warrants			Series D Warrants			NRG Warrants
Balance as of October 31, 2016		7,680,000		3,826,000			—			—			166,000
Warrants issued on May 3, 2017							12,000,000			12,000,000			—
Warrants exercised		—		(3,826,000	)		(419,100	)		(9,415,826	)		—
Warrants expired		—		—			—			—			(166,000	)
Balance as of October 31, 2017		7,680,000		-			11,580,900			2,584,174			-

Other Common Stock Sales

The Company may sell common stock on the open market from time to time. The proceeds of these sales may be used for general corporate purposes or to pay obligations related to the Company's outstanding Series 1 and Series B preferred shares. During the years ended October 31, 2017 and 2016, respectively, the Company sold 7.2 million shares and 6.0 million shares of the Company's common stock at prevailing market prices through periodic trades on the open market and raised approximately $12.6 million and $36.1 million, net of aggregate selling commissions of $0.1 million and $0.1 million, respectively.