15. Public Offerings of Common Stock

On February 20, 2015, the Company entered into a Controlled Equity Offering^SM Sales Agreement (the “2015 Sales Agreement”) with Cantor Fitzgerald & Co. (“Cantor”), as sales agent, pursuant to which the Company sold through Cantor, from time to time, up to $25.0 million in shares of common stock in an at-the-market offering. All sales of shares were made pursuant to an effective shelf registration statement on Form S-3 filed with the SEC. The Company pays Cantor a commission of approximately 3% of the aggregate gross proceeds received from all sales of common stock under the Sales Agreement. Sales under the 2015 Sales Agreement have been fully sold as of February 9, 2016, with cumulative shares of 7,724,488, gross proceeds of $25.0 million and net proceeds of $24.0 million.

On June 11, 2015, the Company sold 16,666,667 shares of common stock at a public offering price of $3.00 per share for aggregate gross proceeds of $50 million in an underwritten firm commitment public offering. Net proceeds after issuance costs were $46.4 million. The closing of the public offering occurred on June 17, 2015. The Company granted the underwriters an option, exercisable for 30 days, to purchase up to an additional 2,500,000 shares of Common Stock.

On July 10, 2015, the underwriters exercised a portion of their option to acquire an additional 2,075,000 shares at the public offering price of $3.00 per share for aggregate additional gross proceeds of $6.2 million. Net proceeds after issuance costs were $5.8 million. The purchase of the option shares closed on July 15, 2015. Total proceeds (including the option) were $52.2 million, net of issuance costs of $4.0 million. The common stock was offered and sold pursuant to the Shelf Registration Statement filed in November 2014 (the “November 2014 Shelf Registration Statement”), which was declared effective on December 19, 2014. The November 2014 Shelf Registration Statement allowed the Company to raise up to $100.0 million through the sale of debt securities, common stock, preferred stock, warrants, or any combination thereof. On March 3, 2016, the Company filed an amendment to the November 2014 Shelf Registration Statement increasing the amount available from $100.0 million to $150.0 million.

On February 9, 2016, the Company entered into a Controlled Equity Offering^SM Sales Agreement (the “2016 Sales Agreement”) with Cantor, as sales agent, pursuant to which the Company can sell through Cantor, from time to time, up to $43.6 million in shares of common stock in an at-the-market offering. All sales of shares have been and will continue to be made pursuant to an effective shelf registration statement on Form S-3 filed with the SEC. The Company pays Cantor a commission of approximately 3% of the aggregate gross proceeds received from all sales of common stock under the 2016 Sales Agreement. Unless otherwise terminated earlier, the 2016 Sales Agreement continues until all shares available under the Sales Agreement have been sold.

The following table summarizes the total sales under the 2015 Sales Agreement and 2016 Sales Agreement for the periods indicated (in thousands, except per share amounts):

	2015 Sales Agreement				2016 Sales Agreement
	Nine Months Ended September 30, 2016		Year Ended December 31, 2015		Nine Months Ended September 30, 2016
Total shares of common stock sold		5,710.2		2,014.3		8,763.4
Average price per share	$	3.23	$	3.25	$	4.70
Gross proceeds	$	18,454	$	6,546	$	41,156
Commissions earned by Cantor	$	553	$	197	$	1,235
Other issuance costs	$	—	$	259	$	185

On April 14, 2014, the Company sold 12,500,000 shares of common stock at a public offering price of $4.00 per share for aggregate gross proceeds of $50.0 million in an underwritten firm commitment public offering. Certain of the Company’s existing stockholders that are affiliated with certain of the Company’s directors purchased $10.0 million of common stock in the public offering. The closing of the public offering occurred on April 21, 2014. The Company granted the underwriters an option, exercisable for 30 days, to purchase up to an additional 1,875,000 shares of Common Stock to cover over-allotments. On April 30, 2014, the underwriters exercised a portion of their over-allotment option to acquire an additional 1,610,000 shares at the public offering price of $4.00 per share for aggregate additional gross proceeds of $6.4 million. The purchase of the over-allotment shares closed on May 5, 2014. Total proceeds were $52.4 million, net of issuance costs of $4.0 million. The common stock was offered and sold pursuant to the Shelf Registration Statement filed in January 2014 (the “January 2014 Shelf Registration Statement”), which was declared effective on April 2, 2014. The January 2014 Shelf Registration Statement allowed the Company to raise up to $100.0 million through the sale of debt securities, common stock, preferred stock, warrants, or any combination thereof. As of September 30, 2016, the Company had $71.2 million available for future financings under such shelf registration statements.