Debt - Expected Principal, Interest and Fee Payments on Debt (Detail) $ in Thousands	Mar. 31, 2019 USD ($)
Debt Disclosure [Abstract]
2022, Principal	$ 15,000
2023, Principal	20,000
2024, Principal	5,000
Total, Principal	40,000
2019, Interest and Fees	2,250
2020, Interest and Fees	3,335
2021, Interest and Fees	3,326
2022, Interest and Fees	2,909
2023, Interest and Fees	1,315
2024, Interest and Fees	1,270
Total, Interest and Fees	14,405
2019, Total	2,250
2020, Total	3,335
2021, Total	3,326
2022, Total	17,909
2023, Total	21,315
2024, Total	6,270
Total	$ 54,405