Federal Income Tax Provision Compared With Statutory Rates (Detail)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Components Of Income Tax Expense Benefit [Line Items]
Statutory regular federal income tax rate	(34.00%)	(34.00%)	(34.00%)
Change in valuation allowance	(13.00%)	(2.30%)	30.40%
Tax return to prior year provision adjustments	16.20%	2.00%	2.70%
Expiration of federal net operating losses	28.20%	20.20%	6.40%
Reduction of net operating loss attributes	(3.70%)	(2.30%)	(1.30%)
State tax benefit (net of federal benefit)	4.10%	18.10%	(6.90%)
Research credits		(3.00%)	(0.60%)
Foreign amounts with no tax benefit	(0.60%)	(0.20%)	0.10%
Non-deductible expenses	6.10%	3.80%	0.80%
Stock option expenses with no tax benefit			3.80%
Other	0.60%	(0.10%)	(0.90%)
Total	3.90%	2.20%	0.50%