Quarterly report pursuant to Section 13 or 15(d)


6 Months Ended
Jun. 30, 2017
INCOME TAXES [Abstract]  

We file an income tax return in the U.S. federal jurisdiction and a margin tax return in Texas. We received notification from the Internal Revenue Service ("IRS") in November 2016 that the December 31, 2014, tax return was selected for audit.  In April 2017 the audit was expanded to include 2015 in connection with the refund claim related to research and development activities.  The audit is ongoing, and we do not expect any adjustment to the return.  If any issues addressed in the audit are resolved in a manner not consistent with our expectation, provisions will be adjusted in the period the resolution occurs.  Tax returns for various jurisdictions remain open for examination for the years 2013 through 2016.  As of June 30, 2017, and December 31, 2016, we recognized no material adjustments in connection with uncertain tax positions.  The effective tax rate varies from the federal statutory rate of 35% primarily as a result of state tax expense and stock option based compensation offset by the manufacturing deduction.  The application for the change in accounting method for inventory from LIFO to FIFO and the change for spare parts inventory are being submitted to the IRS.