The fair value of the trade names acquired was calculated using an income approach (relief from royalty method) and is  being amortized using the straight-line method over the estimated useful life of 4.5 years. The goodwill of $3.5 million generated from this acquisition is primarily related to expected synergies and was assigned to our Enterprise Networks division. The goodwill will not be deductible for U.S. federal income tax purposes. For the years ended December 31, 2013, 2012 and 2011, we incurred integration related expenses and amortization of  acquired intangibles of $1.1 million, $1.5 million and $1.7 million, respectively, related to this acquisition. Our Board of Directors adopted the 1996 Employee Incentive Stock Option Plan (1996 Plan) effective February 14, 1996, as  amended, under which 17.0 million shares of common stock were authorized for issuance to certain employees and officers  through incentive stock options and non-qualified stock options. Options granted under the 1996 Plan typically become exercisable beginning after one year of continued employment, normally pursuant to a four or five-year vesting schedule  beginning on the first anniversary of the grant date, and have a ten-year contractual term. The 1996 Plan expired February 14,  2006, and expiration dates of options outstanding at December 31, 2013 under the 1996 Plan range from 2014 to 2015. 3  Stock Incentive Plans Stock Incentive Program Descriptions On January 23, 2006, the Board of Directors adopted the 2006 Employee Stock Incentive Plan (2006 Plan), which authorizes 13.0 million shares of common stock for issuance to certain employees and officers through incentive stock options and non-qualified stock options, stock appreciation rights, restricted stock and restricted stock units. The 2006 Plan  was adopted by stockholder approval at our annual meeting of stockholders held on May 9, 2006. Options granted under the  2006 Plan typically become exercisable beginning after one year of continued employment, normally pursuant to a four-year  vesting schedule beginning on the first anniversary of the grant date, and have a ten-year contractual term. Expiration dates of options outstanding at December 31, 2013 under the 2006 Plan range from 2016 to 2023. Our stockholders approved the 2010 Directors Stock Plan (2010 Directors Plan) on May 5, 2010, under which 0.5 million  shares of common stock have been reserved. This plan replaces the 2005 Directors Stock Option Plan. The 2010 Directors Plan provides that the Company may issue stock options, restricted stock and restricted stock units to our non-employee directors. Stock awards issued under the 2010 Directors Plan normally become vested in full on the first anniversary of the  grant date. Options issued under the 2010 Directors Plan have a ten-year contractual term. We currently also have options outstanding under the 1995 Directors Plan, as amended, and the 2005 Directors Stock Option Plan. Expiration dates of options outstanding under both plans at December 31, 2013 range from 2014 to 2019. The following table is a summary of our stock options outstanding as of December 31, 2012 and 2013 and the changes that occurred during 2013: (In thousands, except per share amounts) Number of  Options Weighted Average  Exercise Price Weighted Average  Remaining Contractual  Life in Years Aggregate  Intrinsic  Value Options outstanding, December 31, 2012 6,035 $24.81 6.69 $5,154 Options granted 1,005 $23.64 Options cancelled/forfeited (491) $29.60 Options exercised (191) $19.07 Options outstanding, December 31, 2013 6,358 $24.43 6.60 $25,878 Options exercisable, December 31, 2013 3,911 $24.75 5.19 $15,336 All of the options above were issued at exercise prices that approximate fair market value at the date of grant. At December 31, 2013, 6.0 million options were available for grant under the shareholder approved plans. The aggregate intrinsic values in the table above represent the total pre-tax intrinsic value (the difference between  ADTRAN’s closing stock price on the last trading day of 2013 and the exercise price, multiplied by the number of in-the-money options) that would have been received by the option holders had all option holders exercised their options on December 31, 2013. The amount of aggregate intrinsic value will change based on the fair market value of ADTRAN’s stock. The total pre-tax intrinsic value of options exercised during 2013, 2012 and 2011 was $1.1 million, $4.5 million and $39.8 million, respectively. The fair value of options fully vesting during 2013, 2012 and 2011 was $7.7 million, $7.7 million and $7.3 million, respectively. Financial Results 49