Income Taxes - Reconciliation of Provision for Income Taxes (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]
(Benefit from) provision for income taxes at U.S. Federal statutory rate	$ (8,103)	$ (6,193)	$ 478
State taxes	2,940	(824)	(1,034)
Differential in rates on foreign earnings	(1,396)	(4,880)	(9,565)
Losses for which no benefit is taken	4,311	7,279	9,185
Change in valuation allowance	(996)	(1,104)	1,822
Change in liabilities for uncertain tax positions	(35,742)	1,495	(1,666)
Non-deductible stock-based compensation	981	1,974	1,854
Research and development tax credits	(5,044)	0	(2,006)
Non-deductible meals and entertainment	346	208	213
Adjustments related to tax positions taken during prior years	(1,154)	619	(255)
Tax-exempt investment income	(304)	(248)	(71)
Other	(580)	168	394
Total (benefit from) provision for income taxes	$ (44,741)	$ (1,506)	$ (651)