Commitments (Details) - USD ($)	Jun. 17, 2016	Jun. 30, 2016
Debt Instrument [Line Items]
Purchase Obligation		$ 566,000
Loan And Security Agreement \| Revolving Credit Facility
Debt Instrument [Line Items]
Commitment fees	$ 64,000
Loan And Security Agreement \| Term Loan
Debt Instrument [Line Items]
Increase in term loans, principal amount	$ 3,333,334
Interest rate	7.00%
Ratio of indebtedness to net capital	1.25
Collateral account balance, covenant compliance amount	$ 50,000,000
Covenant compliance, deposit account, percent of account balances	50.00%
Final payment of existing term loans	$ 1,000,000
Amendment fee paid	25,000
Final payment on existing term loans, future	1,350,000
Termination fee	$ 200,000
Loan And Security Agreement \| Term Loan \| Prime Rate
Debt Instrument [Line Items]
Basis spread on variable rate	3.25%

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

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Period Type:	duration

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ 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 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Balance Type:	na
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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

The cash outflow for incremental, external costs directly pertaining to an early extinguishment of debt, including legal costs and prepayment penalties, and excluding interest and repayment of debt principal.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Minimum amount of purchase arrangement in which the entity has agreed to expend funds to procure goods or services from a supplier.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Indebtedness divided by net capital.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Amendment Fee Paid

+ References

No definition available.

+ Details

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Namespace Prefix:	zgnx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Debt Instument, Collateral Account Balance, Covenant Compliance Amount

+ References

No definition available.

+ Details

Name:	zgnx_DebtInstrumentCollateralAccountBalanceCovenantComplianceAmount
Namespace Prefix:	zgnx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Debt Instrument, Commitment Fee Paid

+ References

No definition available.

+ Details

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Namespace Prefix:	zgnx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Debt Instrument, Covenant Compliance, Deposit Account, Percent of Account Balances

+ References

No definition available.

+ Details

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Namespace Prefix:	zgnx_
Data Type:	num:percentItemType
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Period Type:	duration

- Definition

Debt Instrument, Final Payment

+ References

No definition available.

+ Details

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Namespace Prefix:	zgnx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Debt Instrument, Increase In Borrowing Capacity

+ References

No definition available.

+ Details

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Namespace Prefix:	zgnx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Base payment to be made for termination of debt instrument under various scenarios outlined in the agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	zgnx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

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- Details

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Namespace Prefix:
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Balance Type:
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- Details

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- Details

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