Summary of Significant Accounting Policies and Select Balance Sheet Information - Schedule of Other Accrued Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Sep. 30, 2016
Accrued Liabilities Current [Abstract]
Accrued professional fees	$ 501	$ 262
Accrued clinical study expense	411	283
Accrued inventory purchases	596	315
Due to customers	41	881
Deferred revenue	62	180
Other	224	249
Total	$ 1,835	$ 2,170