Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Oct. 31, 2013	Oct. 31, 2012
CASH FLOWS FROM OPERATING ACTIVITIES:
Net (loss) income	$ (6,900)	$ 549
Add non-cash items:
Stock-based compensation	1,109	1,138
Depreciation and amortization	1,623	2,296
Other	565	399
Changes in operating assets and liabilities:
Accounts receivable	509	(2,876)
Inventories	(1,146)	(4,115)
Prepaid expenses	(365)	1,002
Accounts payable	2,709	4,950
Accrued expenses	(839)	(206)
Deferred revenue	(1,600)	(1,089)
Net cash (used in) provided by operating activities	(4,335)	2,048
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from sales and maturities of available-for-sale securities	24,031	13,300
Proceeds from sales and maturities of held-to-maturity securities	2,852	2,800
Purchases of available-for-sale securities	(18,386)	(9,836)
Purchases of held-to-maturity securities		(2,445)
Purchases of property and equipment	(1,045)	(1,038)
Net cash provided by investing activities	7,452	2,781
CASH FLOWS FROM FINANCING ACTIVITIES:
Repurchases of common stock		(8,543)
Payments of tax withholdings for vested RSUs, net of proceeds from stock option exercises	(793)	(599)
Net cash (used in) financing activities	(793)	(9,142)
Effect of exchange rate changes on cash and cash equivalents	157	157
Net increase (decrease) in cash and cash equivalents	2,481	(4,156)
Cash and cash equivalents at beginning of period	28,235	29,446
Cash and cash equivalents at end of period	$ 30,716	$ 25,290