Concentrations and Credit Risk (Details Narrative 1)	12 Months Ended
Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012
Concentrations And Credit Risk Details Narrative 1
Percent of revenue from major customer	45.00%	52.00%	66.00%
Percent of trade receivables for 10% or greater customers	84.00%	87.00%
Percent of trade receivable for two other customers	75.00%	74.00%

Name:	BNSO_ConcentrationsAndCreditRiskDetailsNarrative1Abstract
Namespace Prefix:	BNSO_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Risk that one party to the contract will default expressed as a percentage, used as an input to measure fair value.

+ 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_FairValueInputsCounterpartyCreditRisk
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Ratio of an entity's operating income net of tax to its revenue, used as an input to measure fair value.

+ References

+ Details

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

- Definition

Long-term pre-tax operating income as a percentage of net sales, used as an input to measure fair value.

+ References

+ Details

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