Condensed Consolidated Balance Sheets (Unaudited) (USD $)	Mar. 31, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 4,502,838	$ 9,380,059
Accounts receivable, net	5,576,989	4,021,725
Inventory	10,090,474	8,550,457
Prepaid expenses and other current assets	1,896,833	1,988,457
Total current assets	22,067,134	23,940,698
Restricted cash	750,000
Property, plant, and equipment (net of accumulated depreciation of $27,810,527 at March 31, 2013 and$27,394,851 at December 31, 2012)	6,294,470	6,708,237
Leased property under capital lease (net of accumulated depreciation of $258,243 at March 31, 2013 and $129,122 at December 31, 2012)	2,840,677	2,969,799
Note receivable	555,673	570,697
Intangible assets, net	4,634,636	5,270,571
Total assets	37,142,590	39,460,002
Current liabilities:
Borrowings under line of credit		3,380,835
Accounts payable	5,602,713	3,558,157
Accrued expenses	2,206,036	3,828,045
Product warranty reserve	1,872,893	2,671,409
Deferred revenue	2,779,077	2,950,375
Obligations under capital lease	666,633	650,379
Other current liabilities	1,065,125
Total current liabilities	14,192,477	17,039,200
Obligations under capital lease	1,131,871	1,304,749
Deferred revenue	5,766,510	4,362,092
Common stock warrant liability	4,574,655	475,825
Finance obligation	2,544,331
Other liabilities	1,222,711	1,247,833
Total liabilities	29,432,555	24,429,699
Stockholders' equity:
Common stock, $0.01 par value per share; 245,000,000 shares authorized; Issued (including shares in treasury): 63,806,797 at March 31, 2013 and 38,404,764 at December 31, 2012	638,068	384,048
Additional paid-in capital	802,881,237	801,840,491
Accumulated other comprehensive income	965,757	1,004,412
Accumulated deficit	(795,222,645)	(786,646,266)
Less common stock in treasury: 165,906 shares at March 31, 2013 and December 31, 2012	(1,552,382)	(1,552,382)
Total stockholders' equity	7,710,035	15,030,303
Total liabilities and stockholders' equity	$ 37,142,590	$ 39,460,002