Capital Stock - Schedule of Ordinary Shares Reserved for Future Issuance (Detail)	Jan. 31, 2013	Jan. 31, 2012
Class of Stock [Line Items]
Shares reserved for redeemable convertible preference shares	0	13,315,727
Shares reserved for options and restricted stock units	5,818,126	4,960,843
Shares reserved for employee stock purchase plan	460,445	0
Shares reserved for warrants	36,292	36,292