Accrued Liabilities - Schedule of Accrued Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Sep. 30, 2018
Accrued Liabilities Current [Abstract]
Accrued professional fees	$ 433	$ 311
Accrued clinical study expense	2,460	2,839
Accrued purchases	782	533
Customer claim	1,000	1,000
Construction in progress	33	1,199
Deferred rent	123	121
Other	222	262
Total	$ 5,053	$ 6,265