Commitments and Contingencies - Additional Information (Detail) (USD $)	9 Months Ended	12 Months Ended					12 Months Ended						12 Months Ended
	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Equity	Dec. 31, 2012 Adjustment to decrease legal expense	Dec. 31, 2012 Securities and Derivative Lawsuits	Dec. 31, 2012 Securities and Derivative Lawsuits Minimum	Dec. 31, 2012 Securities and Derivative Lawsuits Maximum	Dec. 31, 2012 Securities Action	Dec. 31, 2012 Derivative Actions	Aug. 03, 2012 Derivative Actions	Dec. 31, 2012 Expenses	Dec. 31, 2012 Cancellation fee
Commitments and Contingencies [Line Items]
Operating lease future minimum rental payment		$ 21,000
Operating lease rent expenses		675,000	766,000	1,200,000
Settlement payment		16,000,000											8,400,000	7,600,000
Required payment to class members and attorneys										16,000,000
Number of common stock to be issued to class members and attorneys										2,777,778
Closing bid price of common stock										$ 1.00
Additional number of common stock to be issued to class members and attorneys										1,000,000
Remittance by insurers into Escrow account		16,000,000
Transfer of common stock into Escrow account		2,777,778
Required payment by insurer to plaintiff												800,000
Additional number of common stock to be issued to plaintiff attorneys												225,000
Remittance by insurers into account established by plantiffs' attorneys		800,000
Transfer of common stock into investment brokerage account		225,000
Loss Contingency settlement agreement cash consideration							16,800,000
Loss contingency settlement agreement stock consideration	$ 8,600,000	$ 8,600,000			$ 6,500,000	$ 2,100,000	$ 7,700,000
Loss contingency settlement agreement stock issuable	901,000	3,002,778					3,002,778			2,777,778	225,000
Stock price used to forecast future liability	$ 1.00						$ 1.00
Fair value assumption expected volatility rate	54.00%						60.00%
Fair value assumption risk free interest rate	0.10%						0.16%
Range of final judgment								4 months	6 months