UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549



FORM 10-K/A

(Amendment # 1)



|x | ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
|- | ------------------------------------------------------------------------------------



For the Fiscal Year ended December
31, 2016

or

| ̈ | TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
|- | ----------------------------------------------------------------------------------------



For the transition period from                             
to



Commission File Number: 000-52046









|Delaware                                                       | 36-4151663                          
|-------------------------------------------------------------- | ------------------------------------
|(State or other jurisdiction of incorporation or organization) | (I.R.S. Employer Identification No.)
|                                                               |                                     
|10201 North Loop East
        Houston, Texas                   | 77029                               
|(Address of principal executive offices)                       | (Zip Code)                          

(713) 609-2100

(Registrant’s telephone number,
including area code)

Securities registered pursuant to Section
12(b) of the Act:



|Title of Class                           |  | Name of Each Exchange on Which Registered
|---------------------------------------- |  | -----------------------------------------
|Common stock, par value $0.001 per share |  | The NASDAQ Stock Market                  



Securities registered pursuant to Section
12(g) of the Act: None



Indicate
by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. YES ̈ NOx



Indicate
by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. YES ̈ NOx



Indicate
by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities
Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the Registrant was required to file such reports),
and (2) has been subject to such filing requirements for the past 90 days.   YES ̈
NOx



Indicate
by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive
Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the
preceding 12 months (or for such shorter period that the registrant was required to submit and post such files). YESx NO ̈



Indicate
by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulations S-K (§ 229.405 of this chapter) is not
contained herein, and will not be contained, to the best of Registrant’s knowledge, in definitive proxy or information statements
incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K.x



Indicate by check mark whether the registrant is a large
accelerated filer, an accelerated filer, a non-accelerated filer or a smaller reporting company.  See definitions of
“large accelerated filer”, “accelerated filer” and “smaller reporting company” in Rule 12b-2
of the Exchange Act.



|Large Accelerated Filer ̈ | Accelerated Filerx | Non-Accelerated Filer ̈ | Smaller reporting company ̈
|------------------------ | ------------------ | ---------------------- | --------------------------



Indicate
by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). YES ̈
NOx





The aggregate market value of the voting stock (common stock)
held by non-affiliates of the registrant as of June 30, 2016 was $85,365,877.







At March 1, 2017, there were 16,506,525 shares of the registrant’s
common stock, $.001 par value per share, outstanding.















EXPLANATORY NOTE

We are filing this Amendment No. 1 (“Form 10-K/A”)
to our Annual Report on Form 10-K for the fiscal year ended December 31, 2016, as filed with the Securities and Exchange Commission
on March 24, 2017 (the “Form 10-K”), solely for the purpose of amending and restating in its entirety Item 9A. Controls
and Procedures.

This Form 10-K/A speaks as of the original filing
date of the Form 10-K and does not reflect any events that may have occurred subsequent to the original filing date. Except as
described above, no other changes have been made to the Form 10-K and we are not amending any other part of, or updating any other
disclosures made in, the Form 10-K.

| | Item 9A. | Controls and Procedures
| | -------- | -----------------------

Evaluation of Disclosure Controls and Procedures

In accordance with Exchange Act Rules 13a-15 and 15a-15,
we carried out an evaluation, under the supervision and with the participation of management, including our Chief Executive Officer
and Chief Financial Officer, of the effectiveness of our disclosure controls and procedures as of the end of the period covered
by this report. In that evaluation, our Chief Executive Officer and Chief Financial Officer noted that we had failed to file an
amendment to our October 5, 2016 Form 8-K to provide audited financial statements for Vertex for 2015 and related pro forma information,
and as a result our disclosure controls and procedures were not effective as of December 31, 2016. The deficiency identified in
our disclosure controls and procedures was related to our inability to obtain in a timely manner audited financial statements of
Vertex for a period pre-dating our acquisition and did not impact our current financial reporting or the Company’s current
or historical financial statements.

Design and Evaluation of Internal Control over
Financial Reporting

Pursuant to Section 404 of the Sarbanes-Oxley Act
of 2002, we included a report of management’s assessment of the design and effectiveness of our internal controls as part
of this Annual Report on Form 10-K for the fiscal year ended December 31, 2016. Ernst & Young, LLP, our independent registered
public accounting firm, also attested to our internal control over financial reporting. Management’s report and the independent
registered accounting firm’s attestation report are included on pages 27 and 28 under the captions entitled “Management’s
Report on Internal Control Over Financial Reporting” and “Report of Independent Registered Public Accounting Firm on
Internal Control Over Financial Reporting.”

There has been no change in our internal controls
over financial reporting that occurred during the quarter ended December 31, 2016 that has materially affected, or is reasonably
likely to materially affect, our internal controls over financial reporting.







SIGNATURES

Pursuant
to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this report to
be signed on its behalf by the undersigned, thereunto duly authorized.

|Date: October 19, 2017 |                                                              |                    
|---------------------- | ------------------------------------------------------------ | -------------------
|                       |                                                             
|                       |                                                              |                    
|                       | By:                                                          | /s/ Nicol G. Graham
|                       | Name: Nicol G. Graham
        Title: Chief Financial Officer
|                       |