Income Taxes - Reconciliation of Provision for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Benefit from for income taxes at U.S. Federal statutory rate	$ (5,624)	$ (7,628)	$ (8,103)
State taxes	120	5,368	2,940
Differential in rates on foreign earnings	1,584	4,311	(1,396)
Non-deductible amortization expense	947	3,138	4,311
Change in valuation allowance	2,230	26,053	(996)
Change in liabilities for uncertain tax positions	(1,083)	(8,126)	(35,742)
Non-deductible stock-based compensation	1,398	1,665	981
Research and development tax credits	(178)	(841)	(5,044)
Non-deductible meals and entertainment	395	361	346
Non-deductible acquisition cost	457	0	0
Adjustments related to tax positions taken during prior years	(781)	0	(1,154)
Tax-exempt investment income	0	0	(304)
Other	128	152	(580)
Total provision for (benefit from) income taxes	$ (407)	$ 24,453	$ (44,741)