Net Operating Loss Carryforwards (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
U.S. Federal income tax [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforward, amount	10,165
State income taxes [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforward, amount	4,002
Minimum [Member] | U.S. Federal income tax [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforward, year of expiration	2012
Minimum [Member] | State income taxes [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforward, year of expiration	2014
Maximum [Member] | U.S. Federal income tax [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforward, year of expiration	2023
Maximum [Member] | State income taxes [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforward, year of expiration	2016