CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2010
Cash flows from operating activities:
Net loss .	$ (12,924)	$ (17,798)	$ (14,805)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization .	2,755	3,563	6,393
Share-based compensation .	3,789	2,751	3,290
Asset impairments	790		1,076
Adjustments to provisions for excess and obsolete inventory	596	1,151	905
Adjustments to allowance for doubtful accounts	(30)
Loss on disposal of equipment			24
Changes in operating assets and liabilities:
Accounts receivable .	1,009	5,404	(1,308)
Inventories .	2,284	(1,733)	3,734
Prepaid expenses and other current assets .	49	171	514
Deferred revenue .	(1,613)	(3,895)	(685)
Accounts payable .	(232)	(1,227)	527
Accrued expenses and other liabilities .	862	(711)	(1,867)
Accrued restructuring costs .	(294)	(204)	(2,011)
Net cash used in operating activities .	(2,959)	(12,528)	(4,213)
Cash flows from investing activities:
Purchases of property and equipment .	(1,655)	(2,752)	(811)
Purchases of investments .	(308,872)	(663,516)	(427,294)
Proceeds from maturities and sales of investments .	386,931	814,291	473,125
Net cash provided by investing activities .	76,404	148,023	45,020
Cash flows from financing activities:
Payment of cash distribution to common stockholders		(185,446)	(284,320)
Proceeds from exercise of stock options .	2,444	6,300	233
Net cash provided by (used in) financing activities.	2,444	(179,146)	(284,087)
Net increase (decrease) in cash and cash equivalents .	75,889	(43,651)	(243,280)
Cash and cash equivalents, beginning of year .	60,765	104,416	347,696
Cash and cash equivalents, end of year .	136,654	60,765	104,416
Supplemental cash flow information:
Cash paid for income taxes .	$ 257	$ 193	$ 323