Date when an entity was incorporated

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=51801978&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=49121117&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=51801978&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=49121117&loc=d3e13537-108611

+ Details

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- Definition

Specific incremental costs directly attributable to a proposed or actual offering of securities which are deferred at the end of the reporting period.

+ 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 210.5-02.8)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 340
-SubTopic 10
-Section S99
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=27011391&loc=d3e105025-122735

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 5
-Section A

+ Details

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Period Type:	instant

- Definition

Cash paid for expenses incurred during underwriting activities (the process to review insurance applications, evaluate risks, accept or reject applications, and determine the premiums to be charged) for insurance companies.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3536-108585

+ Details

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- Definition

The cash inflow from the additional capital contribution to the entity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Financing Activities
-URI http://asc.fasb.org/extlink&oid=6513228

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3255-108585

+ Details

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Balance Type:	debit
Period Type:	duration

- Definition

Price of a single share of a number of saleable stocks of a company.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Number of new stock issued during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 29, 30
-Article 5

+ Details

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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Year the entity was founded, in CCYY format.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Number of customers.

+ References

No definition available.

+ Details

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Namespace Prefix:	zen_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Overview and basis of presentation.

+ References

No definition available.

+ Details

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- Details

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- Details

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Balance Type:
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- Details

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Data Type:	na
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- Details

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- Details

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Overview and Basis of Presentation - Additional Information (Details) $ / shares in Units, $ in Thousands, shares in Millions	1 Months Ended	3 Months Ended
	Mar. 31, 2015 USD ($) $ / shares shares	Mar. 31, 2016 Customer $ / shares	Mar. 31, 2015 USD ($) Customer $ / shares
Overview And Basis Of Presentation [Line Items]
Year founded		2007
Reincorporated date		Apr. 30, 2009
Share price \| $ / shares		$ 20.93
Proceeds from follow-on public offering, net of issuance costs			$ 190,794
Customer Concentration Risk \| Accounts Receivable
Overview And Basis Of Presentation [Line Items]
Number of customers \| Customer		0
Customer Concentration Risk \| Accounts Receivable \| Maximum
Overview And Basis Of Presentation [Line Items]
Percentage of total revenue or receivables		10.00%
Customer Concentration Risk \| Sales Revenue, Net
Overview And Basis Of Presentation [Line Items]
Number of customers \| Customer		0	0
Customer Concentration Risk \| Sales Revenue, Net \| Maximum
Overview And Basis Of Presentation [Line Items]
Percentage of total revenue or receivables		10.00%	10.00%
Follow On Public Offering
Overview And Basis Of Presentation [Line Items]
Shares of common stock sold in initial public offering \| shares	8.8
Share price \| $ / shares	$ 22.75		$ 22.75
Proceeds from follow-on public offering, net of issuance costs	$ 190,100
Underwriting discounts and commission on IPO	8,700
Offering expenses	$ 900		$ 900