Income Taxes - Summary of Tax Effects of Temporary Differences (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Intangible assets	$ 10,706	$ 19,348
Net operating losses	16,769	20,272
Compensation accruals	7,681	8,854
Capitalized transaction costs	5,849	10,022
Unrealized loss/(gain)	1,473	5,291
Capital losses	870	417
Other	1,675	977
Gross deferred tax assets	45,023	65,181
Valuation allowance	(3,088)	(5,731)
Gross deferred tax assets after valuation allowance	41,935	59,450
Deferred tax liabilities:
Intangible assets	(9,507)	(11,915)
Gross deferred tax liabilities	(9,507)	(11,915)
Deferred tax assets, net	$ 32,428	$ 47,535