Property, Plant and Equipment, net - Schedule of Property Plant and Equipment (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Abstract]
Land and land improvements	$ 7,565us-gaap_LandAndLandImprovements	$ 55us-gaap_LandAndLandImprovements
Buildings and building improvements	7,265us-gaap_BuildingsAndImprovementsGross	945us-gaap_BuildingsAndImprovementsGross
Furniture and fixtures	1,236us-gaap_FurnitureAndFixturesGross	876us-gaap_FurnitureAndFixturesGross
Equipment	31,983us-gaap_MachineryAndEquipmentGross	22,275us-gaap_MachineryAndEquipmentGross
Leasehold improvements	6,382us-gaap_LeaseholdImprovementsGross	5,147us-gaap_LeaseholdImprovementsGross
Computer hardware and software	5,060xon_ComputerHardwareandSoftware	4,294xon_ComputerHardwareandSoftware
Construction in progress	1,002us-gaap_ConstructionInProgressGross	314us-gaap_ConstructionInProgressGross
Property, plant and equipment, gross	60,493us-gaap_PropertyPlantAndEquipmentGross	33,906us-gaap_PropertyPlantAndEquipmentGross
Less: Accumulated depreciation and amortization	(22,493)	(17,277)
Property, plant and equipment, net	$ 38,000us-gaap_PropertyPlantAndEquipmentNet	$ 16,629us-gaap_PropertyPlantAndEquipmentNet

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (c)

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- Definition

Amount before accumulated depreciation of building structures held for productive use including addition, improvement, or renovation to the structure, including, but not limited to, interior masonry, interior flooring, electrical, and plumbing.

+ References

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- Definition

Amount of structure or a modification to a structure under construction. Includes recently completed structures or modifications to structures that have not been placed into service.

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- Definition

Amount before accumulated depreciation of equipment commonly used in offices and stores that have no permanent connection to the structure of a building or utilities. Examples include, but are not limited to, desks, chairs, tables, and bookcases.

+ References

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- Definition

Amount before accumulated deprecation and depletion of real estate held for productive use and additions or improvements to real estate held for productive use, examples include, but are not limited to, walkways, driveways, fences, and parking lots. Excludes land held for sale.

+ References

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- Definition

Amount before accumulated depreciation of additions or improvements to assets held under a lease arrangement.

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- Definition

Amount before accumulated depreciation of tangible personal property used to produce goods and services, including, but is not limited to, tools, dies and molds, computer and office equipment.

+ References

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

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Amount before accumulated depreciation and amortization of computer hardware and purchased software.

+ References

No definition available.

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