Benefit Plans - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended			12 Months Ended			1 Months Ended
	Oct. 31, 2012	Jan. 31, 2012	May 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jan. 31, 2014 Subsequent Event [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of matching contribution to benefits plan	4.00%	3.00%	2.00%				4.25%
Expenses on contribution charged				$ 0.5	$ 0.4	$ 0.2
Number of shares of common stock issuable under employee stock purchase plan of 2002				55,000
Number of shares issued under employee stock purchase plan				1,098	2,400	4,726
Number of shares available under employee stock purchase plan				3,942