Mandatorily Redeemable Convertible Preferred Stock (Redeemable Convertible Preferred Stock [Member])

12 Months Ended

Dec. 31, 2012

Redeemable Convertible Preferred Stock [Member]

Class of Stock [Line Items]

Common Stock

Mandatorily Redeemable Convertible Preferred Stock

On February 1, 2011, the Company’s registration statement on Form S-1 for its IPO was declared effective by the SEC and on February 7, 2011, the Company closed its IPO. As a result of the IPO, the Company’s mandatorily redeemable convertible preferred stock was automatically converted into common stock.

The following table summarizes information related to the Company’s mandatorily redeemable convertible preferred stock prior to conversion into common stock (in thousands, except par value):

Series	Par Value		Shares Authorized	Shares Outstanding	Liquidation Preference		Proceeds Net of Issuance Costs
A	$	0.001	5,050	4,195	$	4,195	$	4,150
B	0.001		6,250	6,217	64,830		35,455
C	0.001		4,004	2,730	4,348		4,302
			15,304	13,142	$	73,373	$	43,907

The Series A and Cmandatorily redeemable convertible preferred stock converted on a 1:0.786 basis into common stock while the Series B mandatorily redeemable convertible preferred stock converted on a 1:0.908 basis.

Dividends

Holders of Series B Preferred Stock are entitled to receive dividends, in preference to the holders of Series A Preferred Stock, Series C Preferred Stock and common stock, at the simple rate of 8% of the original issue price of $5.71 on each outstanding share of Series B Preferred Stock. The dividends are cumulative and shall be payable, in cash or stock, as determined by the Board of Directors, only upon any consolidation or merger of the Company in which in excess of 50% of the Company's voting power is transferred; the sale, lease or other disposition of all or substantially all of the assets of the Company; upon the automatic conversion in connection with either an initial public offering or the requisite vote of the outstanding preferred stock; or upon the first redemption date. The Company accrued dividends related to Series B Preferred Stock of $2.8 million for the year ended December 31, 2010 and $0.3 million for the three month period ended March 31, 2011. From the proceeds of the IPO, aggregate cumulative dividends of $29.6 million were paid in full to the holders of the Company’s Series B Preferred Stock.

Convertible Preferred Stock Warrants

In June 2000, the Company had issued a warrant to purchase 18,214 shares of Series B Preferred Stock at $5.71 per share. Outstanding warrants were classified as liabilities, which were adjusted to fair value at each reporting period until the earlier of their exercise or expiration or the completion of a liquidation event, including the completion of an IPO. The Company recorded a decrease to general and administrative expense of $15,549 for the year ended December 31, 2009 and an increase to general and administrative expense of $32,752 for the year ended December 31, 2010, to reflect a change in the fair value of these outstanding warrants. Upon the consummation of the IPO in February 2011, the preferred stock warrant was automatically converted to a warrant to purchase shares of common stock in accordance with the terms of the warrant agreement and the warrant was reclassified to stockholders’ equity.