Note 10 - Employee Benefit Plans (Details Textual) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
401(k) Plan [Member]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	10.00%
Defined Contribution Plan Maximum Annual Employer Matching Contribution Per Emplyee Amount	$ 5
Defined Contribution Plan Employer Matching Contribution Vesting Period	4 years
Defined Contribution Plan, Cost	$ 190	$ 121
The Ambrell Plan [Member]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	2.00%
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	100.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	25.00%
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 23	$ 26

Defined contribution plan employer matching contribution vesting period.

No definition available.

Name:	intt_DefinedContributionPlanEmployerMatchingContributionVestingPeriod
Namespace Prefix:	intt_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum dollar amount of employer's annual matching contribution to a defined contribution plan

+ References

No definition available.

+ Details

Name:	intt_DefinedContributionPlanMaximumAnnualEmployerMatchingContributionPerEmplyeeAmount
Namespace Prefix:	intt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of cost for defined contribution plan.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

+ Details

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

- Definition

Amount of discretionary contributions made by an employer to a defined contribution plan.

+ References

No definition available.

+ Details

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

- Definition

Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

+ References

No definition available.

+ Details

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

- Definition

Percentage employer matches of the employee's percentage contribution matched.

+ References

No definition available.

+ Details

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

- Definition

Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_RetirementPlanNameAxis=intt_The401KPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RetirementPlanNameAxis=intt_TheAmbrellPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: