Summary of Significant Accounting Policies - Concentration of Credit Risk (Details) $ in Thousands	3 Months Ended
	Nov. 30, 2017 USD ($) customer	Nov. 30, 2016 USD ($)	Aug. 31, 2017 USD ($)	Aug. 31, 2016 USD ($)
Concentration Risk [Line Items]
Cash and cash equivalents	$ 3,400	$ 4,827	$ 3,582	$ 6,030
Number of Customers | customer	10
Net revenues | Customer concentration
Concentration Risk [Line Items]
Concentration risk (as a percent)	66.00%	67.00%
Net revenues | Geographic concentration
Concentration Risk [Line Items]
Concentration risk (as a percent)	64.00%	76.00%
United States | U.S. Dollars
Concentration Risk [Line Items]
Cash and cash equivalents	$ 587		109
Taiwan | U.S. Dollars
Concentration Risk [Line Items]
Cash and cash equivalents	1,771		2,350
Taiwan | New Taiwan Dollars
Concentration Risk [Line Items]
Cash and cash equivalents	245		81
Taiwan | Other currencies
Concentration Risk [Line Items]
Cash and cash equivalents	700		646
China (including Hong Kong) | U.S. Dollars
Concentration Risk [Line Items]
Cash and cash equivalents	7		7
China (including Hong Kong) | Renminbi
Concentration Risk [Line Items]
Cash and cash equivalents	84		$ 389
China (including Hong Kong) | H.K. dollars
Concentration Risk [Line Items]
Cash and cash equivalents	$ 6