Income Taxes - Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets
Net operating loss, domestic	$ 16,986	$ 4,574
Stock-based and other compensation	15,579	23,105
Unrealized losses on investment	1,739	0
AMT credit carryforward	1,661	1,666
Deferred rent	1,547	462
Partnership income	1,027	0
Capital loss carryforward	344	5,383
Other, net	226	461
Total deferred tax assets	39,109	35,651
Deferred tax liabilities
Partnership income	0	(2,077)
Deferred expenses	(1,268)	(1,391)
Net deferred tax assets	37,841	32,183
Valuation allowance	(344)	(3,535)
Net deferred tax asset	$ 37,497	$ 28,648