Indebtedness (Details) (NT dollar-denominated long-term credit facility, USD $)	1 Months Ended	9 Months Ended
	Jan. 31, 2013	May 31, 2013
NT dollar-denominated long-term credit facility
Indebtedness
Borrowing capacity	$ 4,100,000
Maturity term	3 years
Variable rate basis	Annual time deposit rate
Variable rate spread (as a percent)	0.63%
Amount outstanding		2,900,000
Required monthly payments of principal and interest		$ 82,000
Interest rate at the end of the period (as a percent)		2.00%