Income Taxes - Schedule of Reconciliation of the Company's Effective Tax Rate to the Statutory Federal Income Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]
Federal income tax at statutory federal rate	35.00%	35.00%	35.00%
State taxes	4.30%	4.50%	4.20%
Permanent differences	(2.00%)	(0.20%)	(0.40%)
Stock-based compensation	(0.60%)	(0.30%)	(1.20%)
Tax credits	12.40%	1.10%	3.90%
Foreign rate differential	(2.80%)	(4.10%)	(4.40%)
Other	(1.50%)	(0.50%)	(0.80%)
Change in valuation allowance	(44.80%)	(35.50%)	(36.30%)
Effective income tax rate