Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jan. 28, 2012	Jul. 31, 2011
Current assets:
Cash and cash equivalents	$ 53,347	$ 60,765
Short-term investments	311,456	335,847
Accounts receivable, net of allowance for doubtful accounts of $72 at January 28, 2012 and July 31, 2011	12,267	8,764
Inventories	9,575	11,537
Prepaid and other current assets	2,000	1,770
Total current assets	388,645	418,683
Property and equipment, net	5,846	5,978
Long-term investments	73,710	44,786
Other assets	294	290
Total assets	468,495	469,737
Current liabilities:
Accounts payable	1,300	1,664
Accrued compensation	2,341	2,325
Accrued warranty	1,125	1,140
Accrued expenses	1,447	1,889
Accrued restructuring costs		294
Deferred revenue	11,153	9,141
Other current liabilities	1,134	1,013
Total current liabilities	18,500	17,466
Long term deferred revenue	1,607	1,812
Other long term liabilities	2,115	1,702
Total liabilities	22,222	20,980
Commitments and contingencies (Note 11)
Stockholders' equity:
Preferred stock, $.01 par value; 5,000 shares authorized; none issued or outstanding
Common stock, $.001 par value; 250,000 shares authorized; 28,774 and 28,739 shares issued and outstanding at January 28, 2012 and July 31, 2011, respectively	29	29
Additional paid-in capital	1,585,655	1,583,124
Accumulated deficit	(1,139,266)	(1,133,958)
Accumulated other comprehensive loss	(145)	(438)
Total stockholders' equity	446,273	448,757
Total liabilities and stockholders' equity	$ 468,495	$ 469,737