Stock-Based Compensation - Black-Scholes Option-Pricing Model Assumptions Used to Calculate Fair Value of Employee Stock Options (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Average risk-free interest rate	0.90%	0.90%	1.60%
Dividend yield	0.00%	0.00%	0.00%
Average volatility factor	61.20%	62.20%	63.80%
Average weighted average expected life	5 years 2 months 12 days	5 years	4 years 10 months 24 days