Additional Information for Certain Balance Sheet Accounts (Detail) (USD $) In Thousands, unless otherwise specified	Jul. 31, 2012		Jul. 31, 2011
Accounts receivable, net of allowance:
Billed	$ 91,143		$ 81,314
Unbilled	4,974	[1]	7,244	[1]
Accounts receivable, net of allowance for doubtful accounts of $344 and $599 as of July 31, 2012 and 2011, respectively	96,117		88,558
Inventories:
Raw materials	73,657		75,434
Work-in-process	9,994		10,544
Finished goods	25,293		19,505
Inventories	108,944		105,483
Accrued liabilities:
Accrued employee compensation and benefits	25,153		21,521
Accrued restructuring charges	277		5,190
Accrued warranty	5,634		5,174
Other	10,682		9,553
Accrued liabilities	41,746		41,438
Advance payments and deferred revenue:
Deferred revenue	11,551	[2]	7,380	[2]
Customer deposits	2,772		1,869
Advance payments and deferred revenue	$ 14,323		$ 9,249

[1] Total unbilled receivables at July 31, 2012 and 2011 were $7,653 and $11,617, respectively. At July 31, 2012 and 2011, the long-term portion of unbilled receivables of $2,678 and $4,373, respectively, was included in non-current other assets

[2] Total deferred revenue at July 31, 2012 and 2011 was $12,267 and $8,289, respectively. At July 31, 2012 and 2011, the long-term portion of deferred revenue of $716 and $909, respectively, was included in non-current other liabilities.