Stock-based Compensation (Details) $ / shares in Units, $ in Thousands	1 Months Ended			12 Months Ended
	Apr. 30, 2016 $ / shares shares	May 31, 2015 $ / shares shares	Apr. 30, 2014 shares	Aug. 31, 2016 USD ($) item $ / shares shares	Aug. 31, 2015 USD ($) $ / shares shares
Stock-based Compensation
Number of share-based compensation plans | item				1
Additional number of shares authorized for issuance			250,000
Shares of common stock reserved for issuance				635,000	635,000
Stock-based compensation expense | $				$ 382	$ 1,289
Stock-based compensation tax benefit recognized | $				$ 0	$ 0
Common Stock
Stock-based Compensation
Common stock available for future issuance (in shares)				353,000	388,000
Restricted stock unit
Stock-based Compensation
Stock units granted (in shares)				8,000	15,000
Stock units vested (in shares)				35,000	62,000
Grant-date fair value (in dollars per share) | $ / shares				$ 3.40	$ 7.85
Employee Stock Option
Stock-based Compensation
Estimated forfeiture rate (as a percent)				0.00%
Employee Stock Option | Maximum
Stock-based Compensation
Vesting period				1 year
Employees, directors and nonemployees | Cost of revenues
Stock-based Compensation
Stock-based compensation expense | $				$ 91	$ 285
Employees, directors and nonemployees | Research and development
Stock-based Compensation
Stock-based compensation expense | $				40	149
Employees, directors and nonemployees | Selling, general and administrative
Stock-based Compensation
Stock-based compensation expense | $				$ 251	$ 855
Executives and employees | Restricted stock unit
Stock-based Compensation
Stock units granted (in shares)					10,000
Vesting period					4 years
Vesting percentage on each anniversary of the vesting start date of awards granted					25.00%
Directors | Restricted stock unit
Stock-based Compensation
Stock units granted (in shares)	8,000	5,000
Vesting percentage on the earlier of the first anniversary of the vesting start date and the date of the next annual meeting		100.00%	100.00%
Grant-date fair value (in dollars per share) | $ / shares	$ 3.40	$ 8.20
Number of shares of common stock for which contingent right is established by restricted stock unit (in shares)		1