401(k) Plan - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2012
Benefit Plan [Line Items]
Defined contribution plan description	All of the Company's employees who are United States citizens, at least 21 years of age and have completed at least one quarter of service with the Company.
Defined contribution plan employer discretionary contribution percent	25.00%
Defined contribution plan employee contribution percent	6.00%