million, or 18.1%, year over year. This increase was primarily driven by investments in our efforts to build next generation energy efficient computing architectures. These efforts resulted in a $83.7 million increase in compensation and benefits expense and a $22.5 million increase in stock-based compensation. Development expenses increased by $9.0 million related to the ramp of our Kepler GPU architecture, designed for 28nm technology and our Tegra 3 mobile computing architecture. Depreciation and amortization increased by $8.8 million, driven primarily by amortization of licenses acquired during the year. Also contributing to the increase were other acquisition-related costs of $12.4 million for compensation charges related to the retention program we established for employees from our acquisition of Icera in June 2011 and $6.0 million of amortization expense for intangible assets associated with this acquisition.

Sales, General and Administrative



Fiscal Year 2013 vs. Fiscal Year 2012



Sales, general and administrative expenses increased by $25.2 million, or 6.2%, year over year. This increase was primarily due to a $21.6 million increase in compensation and benefits expense as we continue to invest in our business. Also contributing to the increase was a $20.1 million expense for the net present value of a charitable contribution that we recorded in the second quarter of fiscal year 2013. Offsetting these increases were decreases in outside professional fees of $10.4 million due to an overall decrease in professional services costs during fiscal year 2013 compared with fiscal year 2012 due to a general decline in litigation-related costs and the absence of services associated with acquisition activity in fiscal year 2013.



Fiscal Year 2012 vs. Fiscal Year 2011



Sales, general and administrative expenses increased by $44.1 million, or 12.2%, year over year. Compensation and benefits expense increased by $29.5 million, primarily attributable to employee personnel growth. Stock-based compensation increased by $10.5 million primarily due to a combination of a higher outlay of equity awards as a result of the increase in employee personnel. Also contributing to the increase were $4.4 million of transaction costs related to the acquisition of Icera, $3.5 million for compensation charges related to the retention program we established for Icera employees and $2.2 million of amortization expense for intangible assets associated with the Icera acquisition. Offsetting these increases were decreases in outside professional fees of $4.0 million due to lower litigation-related costs and a decrease in depreciation and amortization of $9.2 million due to certain software and lease-hold improvements of buildings that became fully depreciated during fiscal year 2012.



Legal Settlement

         

On January 10, 2011, we entered into a six-year cross licensing agreement with Intel and also mutually agreed to settle all outstanding legal disputes.  The fair valued benefit prescribed to the legal settlement portion was $57.0 million and was recorded in the fourth quarter of fiscal year 2011.



We expect operating expenses to increase in the