Condensed Consolidated Balance Sheets (USD $)	Sep. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 10,959,955	$ 9,380,059
Accounts receivable, net	4,301,033	4,021,725
Inventory	9,768,654	8,550,457
Prepaid expenses and other current assets	2,120,127	1,988,457
Total current assets	27,149,769	23,940,698
Restricted cash	500,000
Property, plant and equipment, net	5,806,724	6,708,237
Leased property under capital lease, net	2,582,434	2,969,799
Note receivable	525,298	570,697
Intangible assets, net	3,467,536	5,270,571
Total assets	40,031,761	39,460,002
Current liabilities:
Borrowings under line of credit		3,380,835
Accounts payable	4,129,126	3,558,157
Accrued expenses	1,855,898	3,828,045
Product warranty reserve	1,413,225	2,671,409
Deferred revenue	3,387,383	2,950,375
Obligations under capital lease	700,367	650,379
Other current liabilities	1,079,673
Total current liabilities	12,565,672	17,039,200
Obligations under capital lease	773,045	1,304,749
Deferred revenue	5,827,323	4,362,092
Common stock warrant liability	12,895,564	475,825
Finance obligation	2,507,800
Other liabilities	794,662	1,247,833
Total liabilities	35,364,066	24,429,699
Redeemable Preferred Stock Series C redeemable convertible preferred stock, $0.01 par value per share (aggregate involuntary liquidation preference $8,119,916) 10,431 shares authorized; Issued and outstanding: 10,431 at September 30, 2013 and 0 at December 31, 2012	2,451,079
Stockholders' equity:
Common stock, $0.01 par value per share; 245,000,000 shares authorized; Issued (including shares in treasury): 102,603,967 at September 30, 2013 and 38,404,764 at December 31, 2012	1,026,040	384,048
Additional paid-in capital	822,303,366	801,840,491
Accumulated other comprehensive income	947,584	1,004,412
Accumulated deficit	(820,507,992)	(786,646,266)
Less common stock in treasury: 165,906 shares at September 30, 2013 and December 31, 2012	(1,552,382)	(1,552,382)
Total stockholders' equity	2,216,616	15,030,303
Total liabilities, redeemable preferred stock, and stockholders' equity	$ 40,031,761	$ 39,460,002