8. Common Stock

On March 28, 2012, our board of directors and stockholders approved, and we filed, a restated certificate of incorporation effecting a Reverse Stock Split of the outstanding shares of our common stock at a ratio of one share for every 2.023 shares outstanding, so that every 2.023 outstanding shares of common stock (the "Reverse Stock Split") before the Reverse Stock Split represented one share of common stock after the Reverse Stock Split. Each stockholder's percentage ownership interest in the Company and proportional voting power remains unchanged after the Reverse Stock Split, except for minor changes and adjustments resulting from rounding of fractional interests. The rights and privileges of the holders of capital stock were unaffected by the Reverse Stock Split. All information in these financial statements has, unless otherwise indicated, been retroactively adjusted for all periods presented to give effect to the Reverse Stock Split.

On August 13, 2012, we issued and sold in a private placement an aggregate of 897,554 shares of common stock at a price per share of $5.50 resulting in net proceeds of $4.0 million. As a result of the completion of the private placement, on August 13, 2012, our Series A Preferred Stock and Series B Preferred Stock automatically converted into shares of common stock. Each share of Series A Preferred Stock converted into common stock on a one-for-2.023 basis, into a total of 3,064,753 shares of common stock, and each share of Series B Preferred Stock converted into common stock on a one-for-one basis, into a total of 6,770,563 shares of common stock.

In March 2013, we issued and sold in a private placement an aggregate of 3,888,880 shares of our common stock to investors at $9.00 per share. The private placement resulted in $32.7 million of net proceeds. We filed a registration statement covering the resale of all such shares.

In December 2013, we issued 273,224 shares of our common stock to Intrexon Corporation at $9.15 per share. The shares were issued in conjunction with a research and development agreement as the first installment of technology access fee (see Note 3).

In March 2014, we issued and sold in a public offering an aggregate of 5,518,630 shares of our common stock at $10.00 per share, which included 518,630 shares that represented the partial exercise of an overallotment option granted to the underwriters in connection with the offering. This public offering resulted in $51.7 million of net proceeds, after deducting underwriting discounts and commissions and other offering expenses payable by us.

We have reserved the following shares of common stock for the potential exercise of stock options and issuance of shares upon vesting of restricted stock units:

	December 31, 2014		December 31, 2013
Outstanding stock options		3,628,628		2,413,237
Outstanding restricted stock units		54,078		96,155