Commitments and Contingencies - Minimum Fixed Commitments Related to All Non-Cancellable Leases (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Minimum Operating Lease Commitments
2018	$ 3,390
2019	1,466
2020	110
2021	93
Total minimum lease payments	5,059
Minimum Capital Lease Commitments
2018	494
2019	400
2020	20
2021	7
Total minimum lease payments	921
Less: amount representing interest	(106)
Present value of minimum lease payments	815
Less: current obligation	(423)	$ (471)
Long-term obligations under capital lease	$ 392	$ 865