Net Income Per Share (Details Textual) (USD $)	12 Months Ended
Jun. 30, 2012
Net income per share (Textual) [Abstract]
Minimum weighted average price of common stock for share associated with convertible notes to be include in calculation of diluted net income per share	$ 33.69

Minimum weighted average price of common stock for share associated with convertible notes to be include in calculation of diluted net income per share.

No definition available.

Name:	syna_MinimumWeightedAveragePriceOfCommonStockForShareAssociatedWithConvertibleNotesToBeIncludeInCalculationOfDilutedNetIncomePerShare
Namespace Prefix:	syna_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration