Years Ended
	July 27, 2019	July 28, 2018	July 29, 2017	Variance in Dollars	Variance in Percent
Research and development	$ 6,577	$ 6,332	$6,059	$245	4%
Percentage of revenue	12.7%	12.8%	12.6%
Sales and marketing	9,571	9,242	9,184	329	4%
Percentage of revenue	18.4%	18.7%	19.1%
General and administrative	1,827	2,144	1,993	(317)	(15)%
Percentage of revenue	3.5%	4.3%	4.2%
Total	$17,975	$17,718	$17,236	$257	1%
Percentage of revenue	34.6%	35.9%	35.9%