16. Common Stock

During 2010, the Company changed the par value of its common stock from no par to $0.01 par and recognized a $17,547,000 reduction to common stock and a corresponding increase to additional paid-in capital. During the first quarter of 2012, the Company amended its certificate of incorporation to increase the number of authorized shares of common stock to 200.0 million shares of $0.01 par value common stock. As of December 31, 2011 and 2012, the Company had 138.5 million shares and 200.0 million shares, respectively, of $0.01 par value common stock authorized. There were 11,834,000 and 95,825,000 shares of common stock issued and outstanding as of December 31, 2011 and 2012, respectively. The shares reserved for future issuance as of December 31, 2011 and 2012 consisted of the following:

(in thousands)

Conversion of Series B, Series C, Series D, Series E, Series F and Series G convertible preferred stock	66,256	—
Convertible preferred stock warrants	302	—
Common stock warrants	2,640	2,842
Options to purchase common stock	17,617	18,066

	86,815	20,908