Prepaid Expenses and Other Current Assets - Schedule of Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Prepaid insurance	$ 6,711	$ 8,646
Prepaid marketing and advertising costs	2,800	3,202
Other	6,799	7,476
Total prepaid expenses and other current assets	$ 16,310	$ 19,324