Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jan. 31, 2013	Jan. 31, 2012
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (2,727)	$ (14,596)
Add (deduct) non-cash items:
Stock-based compensation	2,378	2,505
Depreciation and amortization	4,262	5,689
Restructuring	300	187
Other	(263)	(728)
Changes in operating assets and liabilities:
Accounts receivable	7,814	20,966
Inventories	(2,345)	(6,791)
Prepaid expenses	574	831
Accounts payable	(3,652)	(8,810)
Accrued expenses	(2,895)	(8,220)
Deferred revenue	(318)	(150)
Net cash provided by (used in) operating activities	3,128	(9,117)
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from sales and maturities of available-for-sale securities	41,720	18,426
Proceeds from sales and maturities of held-to-maturity securities	2,800	5,750
Purchases of available-for-sale securities	(28,379)	(80,966)
Purchases of held-to-maturity securities	(4,842)	(7,885)
Purchases of property and equipment	(1,894)	(1,826)
Net cash provided by (used in) investing activities	9,405	(66,501)
CASH FLOWS FROM FINANCING ACTIVITIES:
Repurchases of common stock	(9,208)	(6,077)
Payments of tax withholdings for vested restricted stock units, net of proceeds from stock option exercises	(1,010)	(1,044)
Proceeds from shares issued from employees' stock purchase plan	389	397
Net cash used in financing activities	(9,829)	(6,724)
Effect of exchange rate changes on cash and cash equivalents	208	(423)
Net increase (decrease) in cash and cash equivalents	2,912	(82,765)
Cash and cash equivalents at beginning of period	29,446	123,198
Cash and cash equivalents at end of period	$ 32,358	$ 40,433