Summary of Share Based Compensation Expense Related to Share Based Payment Awards and Employee Stock Purchases (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 26, 2015	Jun. 27, 2014	Jun. 26, 2015	Jun. 27, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share based compensation expense related to employee stock options, restricted stock awards and employee stock purchase plan	$ 625	$ 356	$ 2,359	$ 1,144
Cost of sales
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share based compensation expense related to employee stock options, restricted stock awards and employee stock purchase plan	55	27	198	73
Research and development, net
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share based compensation expense related to employee stock options, restricted stock awards and employee stock purchase plan	76	15	165	34
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share based compensation expense related to employee stock options, restricted stock awards and employee stock purchase plan	135	55	487	141
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share based compensation expense related to employee stock options, restricted stock awards and employee stock purchase plan	359	259	1,509	896
Operating expense
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share based compensation expense related to employee stock options, restricted stock awards and employee stock purchase plan	$ 570	$ 329	$ 2,161	$ 1,071