RETIREMENT PLAN (Details Textual) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2016	Sep. 30, 2015
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	50.00%
Defined Contribution Plan Employer Contribution Match Maximum Percent Of Employee Contribution	6.00%
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	30.00%
Contribution expense	$ 169	$ 152

The maximum percentage of participant's contribution to the plan that the employer will contribute a matching contribution.

No definition available.

+ Details

Name:	basi_DefinedContributionPlanEmployerContributionMatchMaximumPercentOfEmployeeContribution
Namespace Prefix:	basi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of the cost recognized during the period for defined contribution plans.

+ References

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

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

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