Legal Proceedings - Additional Information (Detail) In Millions, unless otherwise specified	0 Months Ended	1 Months Ended
	May 05, 2004	Aug. 31, 2011 USD ($)	Feb. 15, 2011 USD ($) Patents	Jul. 31, 2013 USD ($)	Mar. 15, 2013 USD ($)	Jul. 31, 2013 Lycatel [Member] USD ($)	Jul. 31, 2013 Lycatel [Member] EUR (€)	Jul. 31, 2013 Mox [Member] USD ($)	Jul. 31, 2013 Mox [Member] EUR (€)
Loss Contingencies [Line Items]
Damages from the Company in an action alleging infringement of two patents related to the activation of phone and gift card			$ 9.1
Number of patents			2
Damages and interest awarded		10.1
Interest accrued rate		0.11%
Interest on damages per annum (Percentage)					9.00%
Total amount of Final Award damages					5.4
Security deposit						0.30	0.25	2.00	1.50
Payment Order									1.5
Accrued litigation expense				$ 10.0
Term of indefeasible right to use	15 years