Debt - Principal and Interest Payments on Debt (Detail) $ in Thousands	Sep. 30, 2017 USD ($)
Debt Disclosure [Abstract]
2019, Principal	$ 7,857
2020, Principal	8,571
2021, Principal	8,572
2022, Principal	5,000
Total, Principal	30,000
2017, Interest	609
2018, Interest	2,445
2019, Interest	2,178
2020, Interest	1,489
2021, Interest	785
2022, Interest	2,535
Total, Interest	10,041
2017, Total	609
2018, Total	2,445
2019, Total	10,035
2020, Total	10,060
2021, Total	9,357
2022, Total	7,535
Total	$ 40,041