Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Apr. 30, 2018	Jan. 31, 2018	Apr. 30, 2017
Statement Of Financial Position [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 1,895	$ 1,326	$ 578
Preferred shares, par value	$ 0.0001	$ 0.0001	$ 0.0001
Preferred shares, shares authorized	10,000,000	10,000,000	10,000,000
Preferred shares, shares issued	0	0	0
Common shares, par value	$ 0.0001	$ 0.0001	$ 0.0001
Common shares, shares authorized	200,000,000	200,000,000	200,000,000
Common shares, shares issued	108,670,688	108,248,568	116,290,358
Common shares, shares outstanding	108,670,688	108,248,568	116,290,358

A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible.

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