9. Common Stock

The Company has authorized 300,000,000 shares of common stock, $0.001 par value, per share, of which 44,704,849 shares were issued and outstanding as of September 30, 2017 and 43,058,827 shares were issued and outstanding as of December 31, 2016.

During the nine months ended September 30, 2017, the Company issued an aggregate of 232,017 shares of common stock upon exercise of stock options, including stock options to purchase 150,000 shares of common stock exercised through net exercise provisions resulting in the issuance of 66,392 shares of common stock and stock options to purchase 165,625 shares of common stock exercised for cash, providing cash proceeds of $0.4 million. No stock options were exercised during the 2016 period.

During the nine months ended September 30, 2017, the Company issued an aggregate of 1,414,005 shares of common stock due to warrant exercises. Net exercise of 89,330 shares of common stock underlying the warrants resulted in the issuance of 49,127 shares of common stock. Additionally, 1,364,878 were exercised resulting in cash proceeds of $3.1 million. No warrants were exercised during the 2016 period.