Balance Sheets - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 5,593,582	$ 7,270,301
Accounts receivable, net of allowance of $93,478 and $131,464 in 2015 and 2014, respectively	6,376,470	6,480,499
Inventories	4,504,282	6,371,903
Prepaid expenses and other current assets	785,211	1,094,837
Total current assets	17,259,545	21,217,540
Property and equipment, net	1,067,321	894,728
Intangible assets, net	635,889	1,379,653
Other assets	264,159	388,850
Total assets	19,226,914	23,880,771
Current liabilities:
Accounts payable	1,840,135	2,353,133
Accrued liabilities	6,058,390	5,259,694
Deferred revenue	7,445,935	6,658,170
Warrants and debt conversion features	794,130	2,134,187
Total current liabilities	16,138,590	16,405,184
Long-term debt	18,429,177	18,388,764
Long-term deferred revenue	2,009,198	976,165
Other liabilities	275,603	660,376
Total liabilities	$ 36,852,568	$ 36,430,489
Stockholders' deficit:
Preferred stock, par value $0.001; 10,000,000 shares authorized, none outstanding at 2015 and 2014
Common stock, par value $0.001; 300,000,000 shares authorized, 21,551,173 and 20,480,874 shares issued at 2015 and 2014, respectively	$ 21,551	$ 20,481
Additional paid in capital	448,517,472	446,241,703
Treasury stock, 4,015 shares at 2015 and 2014	(205,999)	(205,999)
Accumulated deficit	(465,958,678)	(458,605,903)
Total stockholders' deficit	(17,625,654)	(12,549,718)
Total liabilities and stockholders' deficit	$ 19,226,914	$ 23,880,771