Related Party Transaction (Details Textuals) (Related party one, USD $)	Dec. 31, 2009
Related party one
Related Party Transaction [Line Items]
Real property lease agreement, Annual rental expenses	$ 60,000

Total amount of annual capital lease rental payments to related party.

No definition available.

Name:	svt_CapitalLeaseTransactionAnnualRentalPaymentsToRelatedParty
Namespace Prefix:	svt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant