Activity Under Equity Incentive Plans Related to Restricted Stock Units (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Number of RSUs
Granted	$ 2.13	$ 1.37	$ 1.94
Restricted Stock Units Rsus
Number of RSUs
Beginning Balance	33,295	88,400	37,867
Granted	2,000	0	76,532
Forfeited	0	(17,727)	0
Vested	(18,650)	(37,378)	(25,999)
Ending Balance	16,645	33,295	88,400
Restricted Stock
Number of RSUs
Beginning Balance	$ 1.85	$ 2.54	$ 6.45
Granted	$ 3.03	$ 0.00	$ 1.85
Forfeited	$ 0.00	$ 1.85	$ 0.00
Vested	$ 1.98	$ 3.48	$ 6.20
Ending Balance	$ 1.85	$ 1.85	$ 2.54