Summary Of Share Based Compensation Expense Related To Share Based Payment Awards And Employee Stock Purchases (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Jun. 29, 2012	Jul. 01, 2011	Jun. 29, 2012	Jul. 01, 2011
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share based compensation expense related to employee stock options, restricted stock awards and employee stock purchase plan	$ 412	$ 697	$ 1,065	$ 1,586
Cost of Sales
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share based compensation expense related to employee stock options, restricted stock awards and employee stock purchase plan	32	14	68	44
Research and Development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share based compensation expense related to employee stock options, restricted stock awards and employee stock purchase plan	36	56	99	159
Sales and marketing
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share based compensation expense related to employee stock options, restricted stock awards and employee stock purchase plan	58	148	113	380
General and Administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share based compensation expense related to employee stock options, restricted stock awards and employee stock purchase plan	286	479	785	1,003
Operating Expense
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share based compensation expense related to employee stock options, restricted stock awards and employee stock purchase plan	$ 380	$ 683	$ 997	$ 1,542