Number of major customer.

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- Definition

Organization consolidation and presentation of financial statements.

+ References

No definition available.

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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 cash inflow from realized tax benefit related to deductible compensation cost reported on the entity's tax return for equity instruments in excess of the compensation cost for those instruments recognized for financial reporting purposes.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 20
-Section 55
-Paragraph 24
-URI http://asc.fasb.org/extlink&oid=65896087&loc=d3e11374-113907

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- Definition

Cash and equivalents whose use in whole or in part is restricted for the long-term, generally by contractual agreements or regulatory requirements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.1)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Description of Business and Basis of Presentation - Additional Information (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Apr. 30, 2017 USD ($) Customer	Apr. 30, 2016 Customer	Jan. 31, 2017 USD ($) Customer
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Restricted cash \| $	$ 26,781		$ 26,781
Excess tax benefits from employee stock option exercises included in net operating loss and research and development tax credit forwards \| $	$ 25,200
Credit Concentration Risk \| Accounts Receivable
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of major customer \| Customer	1		2
Concentration risk percentage	10.00%		10.00%
Customer Concentration Risk \| Revenue
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of major customer \| Customer	0	0
Concentration risk percentage	10.00%	10.00%
Geographic Concentration Risk \| Revenue \| United States
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Concentration risk percentage	78.00%	83.00%
Geographic Concentration Risk \| Property and Equipment \| United States
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Concentration risk percentage	99.70%		99.70%