UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 8)*

(Name of Issuer)

(Title of Class of Securities)

(CUSIP Number)

Becker Drapkin Management, L.P.

Attn: Steven R. Becker

500 Crescent Court, Suite 230

Dallas, Texas 75201

(214) 756-6016

with a copy to:

Taylor H. Wilson

Haynes and Boone, LLP

2323 Victory Avenue, Suite 700

Dallas, Texas 75219

(214) 651-5615

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

(Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.  ¨

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See §240.13d-7 for other parties to whom copies are to be sent.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

This Amendment No. 8 to Schedule 13D (this “Amendment No. 8”) is filed by and on behalf of each of the Reporting Persons to amend the Schedule 13D related to the Common Stock of the Issuer previously filed by the Reporting Persons with the Securities and Exchange Commission (the “Commission”) on February 19, 2010, as amended and/or supplemented by Amendment No. 1 to the Schedule 13D filed on May 10, 2010, Amendment No. 2 to the Schedule 13D filed on July 8, 2010, Amendment No. 3 to the Schedule 13D filed on August 31, 2010, Amendment No. 4 to the Schedule 13D filed on March 2, 2011, Amendment No. 5 to the Schedule 13D filed on March 7, 2011, Amendment No. 6 to the Schedule 13D filed on June 7, 2011 and Amendment No. 7 to the Schedule 13D filed on January 9, 2012 (as amended, the “Schedule 13D”). This Amendment No. 8 is filed to disclose a change in the beneficial ownership of each Reporting Person relating to the disposition of shares of Common Stock of the Issuer. Each capitalized term used and not defined herein shall have the meaning assigned to such term in the Schedule 13D. Except as otherwise provided herein, each Item of the Schedule 13D remains unchanged.

Item 5. Interest in Securities of the Issuer.

Item 5(a) is amended and restated in its entirety as follows:

(a) Each Reporting Person declares that neither the filing of this Statement nor anything herein shall be construed as an admission that such person is, for the purposes of Section 13(d) or 13(g) of the Act or any other purpose, the beneficial owner of any securities covered by this Statement.

The aggregate number and percentage of the class of securities identified pursuant to Item 1 beneficially owned by each Reporting Person is stated in Items 11 and 13 on the cover page(s) hereto.

Item 5(b) is amended and restated in its entirety as follows:

(b) Number of shares as to which each Reporting Person has:

See Item 7 on the cover page(s) hereto.

See Item 8 on the cover page(s) hereto.

See Item 9 on the cover page(s) hereto.

See Item 10 on the cover page(s) hereto.

Becker Drapkin QP has the power to vote or to direct the vote of (and the power to dispose or direct the disposition of) the shares owned by it (the “Becker Drapkin QP Shares”). Becker Drapkin QP disclaims beneficial ownership of the Becker Drapkin, L.P. Shares.

Becker Drapkin, L.P. has the power to vote or to direct the vote of (and the power to dispose or direct the disposition of) the shares owned by it (the “Becker Drapkin, L.P. Shares,” and together with the Becker Drapkin QP Shares, the “Becker Drapkin Funds Shares”). Becker Drapkin, L.P. disclaims beneficial ownership of the Becker Drapkin QP Shares.

As general partner of the Becker Drapkin Funds, BD Management may be deemed to have the shared power to vote or direct the vote of (and the shared power to dispose or direct the disposition of) the Becker Drapkin Funds Shares. BD Management does not own any shares of Common Stock directly and disclaims beneficial ownership of the Becker Drapkin Funds Shares.

As general partner of BD Management, BCA may be deemed to have the shared power to vote or direct the vote of (and the shared power to dispose or direct the disposition of) any shares of Common Stock beneficially owned by BD Management. BCA does not own any shares of Common Stock directly and disclaims beneficial ownership of any shares of Common Stock beneficially owned by BD Management.

Mr. Becker has the sole power to vote or to direct the vote of (and the power to dispose or direct the disposition of) the shares owned by him (the “Becker Shares”). Mr. Becker disclaims beneficial ownership of any shares of Common Stock beneficially owned by Mr. Drapkin.

Mr. Drapkin has the sole power to vote or to direct the vote of (and the power to dispose or direct the disposition of) the shares owned by him (the “Drapkin Shares”). Mr. Drapkin disclaims beneficial ownership of any shares of Common Stock beneficially owned by Mr. Becker.

As co-managing members of BCA, each of Mr. Becker and Mr. Drapkin may be deemed to have the shared power to vote or direct the vote of (and the shared power to dispose or direct the disposition of) any shares of Common Stock beneficially owned by BCA. Each of Messrs. Becker and Drapkin disclaims beneficial ownership of any shares of Common Stock beneficially owned by BCA.

As of the date hereof, no Reporting Person owns any Common Stock other than as set forth in this Item 5.

Item 5(c) is amended and restated in its entirety as follows:

(c) Transactions in the class of securities reported on that were effected during the past sixty days or since the most recent filing of Schedule 13D, whichever is less, by the Reporting Persons are described below:

Item 7. Material to be Filed as Exhibits.

Item 7 is amended and restated in its entirety as follows:

The following exhibits are filed as exhibits hereto:

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

EXHIBIT INDEX