Income Taxes (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Federal [Member]	Dec. 31, 2002 Federal [Member]	Dec. 31, 2012 State [Member]
Operating Loss Carryforwards [Line Items]
Period of time for IRS enforced limitation of NOL carryforward on company after an ownership change	3 years
Percentage points of the market value, minimum (in hundredths)	50.00%
Operating loss carryforwards, restricted				$ 4,000,000	$ 10,100,000
Operating loss carryforwards, unrestricted	135,900,000			166,700,000		97,600,000
Operating loss carryforwards annually				363,000
Tax credit carryforward related to research and development	7,500,000
Tax credit carryforwards related to alternative minimum tax	12,200,000
Expiration date	2022 through 2031
Deferred tax valuation allowance has been recorded against these assets (in hundredths)	100.00%
Deferred tax assets [Abstract]
Net operating loss carryforwards	60,184,000	56,025,000
Tax credit carryforwards	15,514,000	10,040,000
Equipment, furnishings and other	9,822,000	9,154,000
Total deferred tax assets	85,520,000	75,219,000
Deferred tax liabilities	(100,000)	(3,868,000)
Net deferred tax assets	85,420,000	71,351,000
Valuation allowance	(85,420,000)	(71,351,000)
Deferred Tax Assets, Net of Valuation Allowance	0	0
Net change in valuation allowance	14,100,000	16,200,000
Federal statutory rate to net loss before income taxes [Abstract]
Federal benefit at statutory rate	(6,107,000)	(4,996,000)	139,000
State income taxes, net of Federal taxes	(745,000)	(857,000)	24,000
State credits	(1,555,000)	0	0
Warranty liabilities	941,000	0	0
Other permanent differences	(23,000)	6,000	22,000
Book gain in excess of tax gain	0	0	(3,630,000)
Provision related to change in valuation allowance	14,069,000	16,235,000	3,278,000
Other, net	(6,578,000)	(10,290,000)	167,000
Provision for income taxes	1,600	97,996	0
Unrecognized tax benefits period increase decrease	0
Unrecognized tax benefits accrued interest or penalties	$ 0	$ 0	$ 0