Provision for Income Taxes (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2013	Jul. 31, 2012
Disclosure Provision For Income Taxes Abstract
Income tax benefit	$ (2,338)	$ (2,764)	$ (1,770)	$ (1,983)
Effective tax rate	(10.90%)	(18.70%)	(8.20%)	(4.60%)