SUBSEQUENT EVENTS (Details) (Subsequent Event [Member], Director [Member])	0 Months Ended
Apr. 22, 2015 Director
Subsequent Event [Member] \| Director [Member]
Subsequent Event [Line Items]
Number of board of directors appointed	2

Refers to number of number of board of directors appointed in the organization.

No definition available.

Name:	bstc_NumberOfBoardOfDirectorsAppointed
Namespace Prefix:	bstc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration