Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Oct. 27, 2012	Oct. 29, 2011
Cash flows from operating activities:
Net loss	$ (6,756)	$ (1,614)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	635	716
Share-based compensation	840	974
Adjustments to provision for excess and obsolete inventory	88	73
Changes in operating assets and liabilities:
Accounts receivable	2,065	(572)
Inventories	(518)	1,725
Prepaids and other assets	835	586
Deferred revenue	(2,653)	(2,188)
Accounts payable	(655)	(1,058)
Accrued expenses and other current liabilities	(882)	(843)
Accrued restructuring costs	1,988	(290)
Net cash used in operating activities	(5,013)	(2,491)
Cash flows from investing activities:
Purchases of property and equipment	(1)	(824)
Purchases of investments		(51,719)
Proceeds from maturities and sales of investments	262,751	45,870
Net cash provided by (used in) investing activities	262,750	(6,673)
Cash flows from financing activities:
Payment of cash distribution to common stockholders	(288,821)
Proceeds from issuance of common stock	38	180
Net cash (used in) provided by financing activities	(288,783)	180
Net decrease in cash and cash equivalents	(31,046)	(8,984)
Cash and cash equivalents, beginning of period	136,654	60,765
Cash and cash equivalents, end of period	105,608	51,781
Cash paid for income taxes	$ 47	$ 31