Certain of the amounts in the above tables may not total due to rounding of individual amounts.

Total share-based compensation expense related to the Company’s stock options, restricted stock units, stock grant awards, and employee stock purchase plan is included below.

		Quarter Ended												Year Ended
		December 31, 2019				September 27, 2019				December 31, 2018				December 31, 2019				December 31, 2018
Cost of revenue		$	2.9			$	2.3			$	1.9			$	10.6			$	7.0
Research and development		4.6				3.4				3.7				17.0				14.3
Selling and marketing		3.7				2.7				3.6				14.8				14.1
General and administrative		6.5				6.3				9.7				37.0				42.9
Total share-based compensation expense		$	17.7			$	14.7			$	18.9			$	79.4			$	78.3

To supplement the consolidated financial results prepared in accordance with GAAP, ON Semiconductor uses certain non-GAAP measures, which are adjusted from the most directly comparable GAAP measures to exclude items related to the amortization of intangible assets, amortization of acquisition-related intangibles, expensing of appraised inventory fair market value step-up, inventory valuation adjustments, purchased in-process research and development expenses, restructuring, asset impairments and other, net, goodwill impairment charges, gains and losses on debt prepayment, non-cash interest expense, actuarial (gains) losses on pension plans and other pension benefits, third party acquisition and divestiture related costs, tax impact of these items, and certain other non-recurring items, as necessary. Management does not consider the effects of these items in evaluating the core operational activities of ON Semiconductor. Management uses these non-GAAP measures internally to make strategic decisions, forecast future results, and evaluate ON Semiconductor’s current performance. In addition, we believe that most analysts covering ON Semiconductor use the non-GAAP measures to evaluate ON Semiconductor’s performance. Given management’s and other relevant use of these non-GAAP measures, ON Semiconductor believes these measures are important to investors in understanding ON Semiconductor’s current and future operating results as seen through the eyes of management. In addition, management believes these non-GAAP measures are useful to investors in enabling them to better assess changes in ON Semiconductor’s core business across different time periods. These non-GAAP measures are not prepared in accordance with, and should not be considered alternatives or necessarily superior to, GAAP financial data and may be different from non-GAAP measures used by other companies. Because non-GAAP financial measures are not standardized, it may not be possible to compare these financial measures with other companies’ non-GAAP financial measures, even if they have similar names.