Income Taxes - Summary of Deferred Tax Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Deferred tax assets:
Accrued expenses	$ 4,429	$ 4,552
Stock-based compensation	3,688	5,382
NOLs - Foreign	3,291	4,551
Deferred rent liability	1,952	2,024
NOLs - U.S.	1,398	1,611
Unrealized losses, net	242	101
Other	329	227
Deferred tax assets	15,329	18,448
Deferred tax liabilities:
Fixed assets	2,386	2,405
Unrealized gains, net	2,641
Incentive compensation	338	1,365
Goodwill and intangible assets	522	301
Deferred tax liabilities	5,887	4,071
Total deferred tax assets less deferred tax liabilities	9,442	14,377
Less: valuation allowance	(3,291)	(4,551)
Deferred tax assets, net	$ 6,151	$ 9,826