UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

October 18, 2013

Date of Report (Date of earliest event reported)

Item 8.01 Other Events.

On October 18, 2013, in the press release attached hereto as Exhibit 99.1 and incorporated herein by reference, we announced the pricing of an underwritten public offering of 2,476,995 shares of our common stock at a price to the public of $16.50 per share. All of the shares are being sold by certain of our existing stockholders. In addition, the selling stockholders have granted the underwriters a 30-day option to purchase up to an additional 371,549 shares of common stock to cover over-allotments, if any. The offering is expected to close on October 23, 2013, subject to customary closing conditions. We will not receive any proceeds from the sale of the shares. The principal purposes of the offering are to facilitate an orderly distribution of shares and to increase the company's public float.

Morgan Stanley & Co. LLC and Cowen and Company, LLC are acting as joint book-running managers for the offering. William Blair & Company, L.L.C. and Canaccord Genuity Inc. are acting as co-managers for the offering.

A registration statement relating to these securities was declared effective by the Securities and Exchange Commission on October 18, 2013. The offering will be made only by means of a prospectus. Copies of the prospectus relating to the offering may be obtained from: Morgan Stanley & Co. LLC, Attn: Prospectus Department, 180 Varick Street, New York, New York 10014, or by calling toll free 1-866-718-1649 or emailing at prospectus@morganstanley.com; or Cowen and Company, LLC, c/o Broadridge Financial Solutions, 1155 Long Island Avenue, Edgewood, NY 11717, Attn: Prospectus Department, by calling (631) 274-2806, or faxing (631) 254-7140.

Neither the disclosures on this Form 8-K nor the press release shall not constitute an offer to sell or the solicitation of an offer to buy these securities, nor shall there be any sale of these securities in any state or jurisdiction in which such an offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

INDEX TO EXHIBITS