Current Liabilities and Debt Obligations (Details) (USD $)	3 Months Ended			12 Months Ended
	Mar. 31, 2014		Mar. 31, 2013	Dec. 31, 2000	Dec. 31, 2013	Jun. 11, 2013	Dec. 31, 2010
Accounts Payable and Other Accrued Payables [Abstract]
Trade account payables	$ 10,500,000				$ 17,300,000
Accrued trade payables	4,700,000				6,000,000
Senior Revolving Credit Facility [Abstract]
Maximum revolving credit facility							30
Debt Instrument, Fee Amount	75,000
Term loan component of Facility					6,200,000
Principal amount of term loan repaid in quarterly installments				93,750
Interest expense	1,340,000		1,407,000
Discount rate on senior redeemable preferred stock redemption (in hundredths)	4.25%					10.00%
Maximum redemption of redeemable preferred stock						2,000,000
Amortization of debt issuance costs	18,000		18,000
Outstanding borrowing of credit facility						400,000
Remaining borrowing capacity	5,000,000
Weighted average interest rates on outstanding borrowings (in hundredths)	5.60%		5.20%
Maturities of facility presented by year [Abstract]
2014	844,000
2015	10,371,000
Total	11,215,000
Warranty Liability [Abstract]
Accrued warranty liability
Term Loan [Member]
Senior Revolving Credit Facility [Abstract]
Term loan component of Facility	6,100,000
Principal amount of term loan repaid in quarterly installments	250,000
Percentage of term loan amortized per year (in hundredths)	5.00%
Revolving credit [Member]
Senior Revolving Credit Facility [Abstract]
Percentage added to reference rate to compute the variable rate (in hundredths)	3.75%
Interest expense	200,000		200,000
Outstanding borrowing of credit facility	11,200,000				19,800,000
Remaining borrowing capacity					9,200,000
Revolving credit [Member] | Prime Rate [Member]
Senior Revolving Credit Facility [Abstract]
Percentage added to reference rate to compute the variable rate (in hundredths)	1.00%
Revolving credit [Member] | Federal Funds Rate [Member]
Senior Revolving Credit Facility [Abstract]
Percentage added to reference rate to compute the variable rate (in hundredths)	1.50%
Revolving credit [Member] | LIBOR Rate [Member]
Senior Revolving Credit Facility [Abstract]
Percentage added to reference rate to compute the variable rate (in hundredths)	2.00%
Short-term [Member]
Maturities of facility presented by year [Abstract]
2014	800,000				700,000
Short-term [Member] | Term Loan [Member]
Maturities of facility presented by year [Abstract]
2014	844,000	[1]
2015	0	[1]
Total	844,000	[1]
Long-term [Member]
Senior Revolving Credit Facility [Abstract]
Term loan component of Facility	5,300,000
Maturities of facility presented by year [Abstract]
2014	0
2015	10,371,000
Total	10,371,000
Long-term [Member] | Term Loan [Member]
Maturities of facility presented by year [Abstract]
2014	0	[1]
2015	5,250,000	[1]
Total	5,250,000	[1]
Long-term [Member] | Revolving credit [Member]
Maturities of facility presented by year [Abstract]
2014	0	[2]
2015	5,121,000	[2]
Total	$ 5,121,000	[2]

[1] The principal will be repaid in 2 quarterly installments of $93,750 in the first half of 2014, and effective July 1, 2014, quarterly installments of $250,000, with a final installment of the unpaid principal amount payable on November 13, 2015.

[2] Balance due represents balance as of December 31, 2013, with fluctuating balances based on working capital requirements of the Company.