The number of customers accounting for ten percent or more of our total revenues.

No definition available.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=64851502&loc=d3e6351-108592

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13531-108611

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=64851502&loc=d3e6404-108592

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13537-108611

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- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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- Details

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Segment Reporting - Additional Information (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Jan. 31, 2017 USD ($)	Oct. 31, 2016 USD ($)	Jul. 31, 2016 USD ($)	Apr. 30, 2016 USD ($)	Jan. 31, 2016 USD ($)	Oct. 31, 2015 USD ($)	Jul. 31, 2015 USD ($)	Apr. 30, 2015 USD ($)	Jan. 31, 2017 USD ($) customer	Jan. 31, 2016 USD ($) customer	Jan. 31, 2015 USD ($) customer
Concentration Risk [Line Items]
Total revenues	$ 477,968	$ 322,516	$ 254,344	$ 227,639	$ 337,267	$ 290,516	$ 281,062	$ 272,143	$ 1,282,467	$ 1,180,988	$ 1,244,133
Geographic concentration risk \| Sales Revenue, Net [Member] \| KOREA, REPUBLIC OF
Concentration Risk [Line Items]
Total revenues											$ 135,696
Percent of total revenues											10.90%
Geographic concentration risk \| Sales Revenue, Net [Member] \| CHINA
Concentration Risk [Line Items]
Total revenues									$ 188,641
Percent of total revenues									14.70%
Customer concentration risk \| Sales Revenue, Net [Member]
Concentration Risk [Line Items]
Customers accounting for ten percent or more of net revenue \| customer									0	0	0
Percent of total revenues									10.00%	10.00%	10.00%