Quantitative Range of Significant Unobservable Inputs Used in Calculation of Fair Value of Continent Consideration Liability (Detail) - USD ($) $ in Thousands	6 Months Ended
Jul. 02, 2016	Jan. 02, 2016
Business Acquisition, Contingent Consideration [Line Items]
Fair Value	$ 748	$ 890
Fair Value, Inputs, Level 3 \| Revenue Earnout
Business Acquisition, Contingent Consideration [Line Items]
Valuation technique	Discounted cash flow
Fair Value	$ 748
Fair Value, Inputs, Level 3 \| Revenue Earnout \| Weighted Average
Business Acquisition, Contingent Consideration [Line Items]
Weighted average cost of capital	13.50%
Probability weighting of achieving revenue forecasts	30.30%
Fair Value, Inputs, Level 3 \| Revenue Earnout \| Minimum
Business Acquisition, Contingent Consideration [Line Items]
Probability weighting of achieving revenue forecasts	10.00%
Fair Value, Inputs, Level 3 \| Revenue Earnout \| Maximum
Business Acquisition, Contingent Consideration [Line Items]
Probability weighting of achieving revenue forecasts	80.00%

Percentage of probability weighting of achieving revenue forecasts.

No definition available.

Name:	ivac_PercentageOfProbabilityWeightingOfAchievingRevenueForecasts
Namespace Prefix:	ivac_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- 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

Name:	us-gaap_BusinessAcquisitionContingentConsiderationLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount, measured at acquisition-date fair value, of all liabilities assumed that arise from contingencies and were recognized by the entity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(1)
-URI http://asc.fasb.org/extlink&oid=56956791&loc=d3e4845-128472

+ Details

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

- Definition

Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)
-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueInputsDiscountRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Description of the inputs and valuation technique(s) used to measure fair value.

+ References

+ Details

Name:	us-gaap_FairValueMeasurementsValuationTechniques
Namespace Prefix:	us-gaap_
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_ContingentConsiderationByTypeAxis=ivac_RevenueEarnoutMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_WeightedAverageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: