The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=66011266&loc=d3e33918-111571

+ Details

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=66022249&loc=d3e33749-111570

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.12)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_EquityMethodInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of increase in assets, excluding financial assets, lacking physical substance with a definite life, from an acquisition.

+ References

No definition available.

+ Details

Name:	us-gaap_FinitelivedIntangibleAssetsAcquired1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Fair value portion of investments in an entity not consolidated. Includes, but is not limited to, investments in an entity that is affiliated with the reporting entity by means of direct or indirect ownership, an entity in which the reporting entity shares control of the entity with another party or group, an entity which the company has significant influence, but does not have control and subsidiaries that are not required to be consolidated and are accounted for using the equity or cost method.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19190-110258

+ Details

Name:	us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVenturesFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Aggregation of the liabilities reported on the balance sheet measured at fair value on a recurring basis by the entity.

+ References

No definition available.

+ Details

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

- Definition

The net cash outflow or inflow from purchases, sales and disposals of property, plant and equipment and other productive assets, including intangibles.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
-URI http://asc.fasb.org/extlink&oid=6516133

+ Details

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

- Definition

The cash outflow associated with the investment in or advances to an entity in which the reporting entity shares control of the entity with another party or group.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3213-108585

+ Details

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

- Definition

Number of shares of stock issued during the period as part of a transaction to acquire assets that do not qualify as a business combination.

+ References

No definition available.

+ Details

Name:	us-gaap_StockIssuedDuringPeriodSharesPurchaseOfAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Value of shares of stock issued during the period as part of a transaction to acquire assets that do not qualify as a business combination.

+ References

No definition available.

+ Details

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

- Definition

Maximum amount of contingent consideration payable in the form of common stock of the entity to former owners of assets acquired other than through a business combination.

+ References

No definition available.

+ Details

Name:	xon_AssetAcquisitionContingentConsiderationPayableinEquityMaximum
Namespace Prefix:	xon_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount, measured at transaction-date fair value, of all liabilities assumed that arise from contingencies associated with assets acquired other than through a business combination and were recognized by the entity.

+ References

No definition available.

+ Details

Name:	xon_AssetAcquisitionLiabilitiesArisingfromContingenciesAmountRecognized
Namespace Prefix:	xon_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of additional capital contributions to the joint venture for which the entity is committed, maximum.

+ References

No definition available.

+ Details

Name:	xon_JointVentureAdditionalCapitalContributionsCommitted
Namespace Prefix:	xon_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Schedule Of Investments In Joint Venture [Line Items]

+ References

No definition available.

+ Details

Name:	xon_ScheduleOfInvestmentsInJointVentureLineItems
Namespace Prefix:	xon_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=xon_EnviroFlightLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BalanceSheetLocationAxis=xon_InvestmentsInAffiliatesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=us-gaap_InvestorMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ResearchAndDevelopmentAssetsAcquiredOtherThanThroughBusinessCombinationByTransactionAxis=xon_EnviroFlightLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_IntellectualPropertyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Investments in Joint Ventures - EnviroFlight - Additional Information (Details) - USD ($)	1 Months Ended	6 Months Ended
	Feb. 29, 2016	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Schedule Of Investments In Joint Venture [Line Items]
Cash paid in asset acquisition		$ 7,244,000	$ 0
Shares issued in asset acquisition		4,401,000	0
Contingent consideration assumed in asset acquisition		3,660,000	$ 0
Investment		22,714,000		$ 9,977,000
Significant Unobservable Inputs (Level 3)
Schedule Of Investments In Joint Venture [Line Items]
Fair value of financial liabilities measured at fair value on a recurring basis		3,660,000
EnviroFlight, LLC
Schedule Of Investments In Joint Venture [Line Items]
Capital contributions	$ 3,000,000
Membership interest	50.00%
Maximum additional capital contribution committed	$ 5,000,000
Estimated fair value of investment	$ 5,425,000
EnviroFlight, LLC \| Investments In Affiliates
Schedule Of Investments In Joint Venture [Line Items]
Investment		4,973,000
EnviroFlight, LLC \| Investors
Schedule Of Investments In Joint Venture [Line Items]
Membership interest	50.00%
Maximum additional capital contribution committed	$ 5,000,000
EnviroFlight, LLC
Schedule Of Investments In Joint Venture [Line Items]
Cash paid in asset acquisition	$ 4,244,000
Shares issued in asset acquisition (in shares)	136,340
Shares issued in asset acquisition	$ 4,401,000
Contingent consideration assumed in asset acquisition	3,660,000
Contingent consideration payable in common stock, maximum	5,500,000
EnviroFlight, LLC \| Significant Unobservable Inputs (Level 3)
Schedule Of Investments In Joint Venture [Line Items]
Fair value of financial liabilities measured at fair value on a recurring basis		$ 3,660,000
EnviroFlight, LLC \| Patents, related technologies and know-how
Schedule Of Investments In Joint Venture [Line Items]
Estimated fair value of developed technology acquired	$ 9,880,000
Expected useful life of intangible asset	21 years