Balance Sheets - USD ($)	Jun. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 5,035,463	$ 8,501,392
Accounts receivable, net of allowance of $603,588 and $379,817 in 2017 and 2016, respectively	4,876,716	4,665,959
Inventories	4,984,115	5,381,103
Prepaid expenses and other current assets	617,412	855,295
Total current assets	15,513,706	19,403,749
Property and equipment, net	792,367	1,086,244
Intangible assets, net	336,908	436,569
Other assets	41,047	39,241
Total assets	16,684,028	20,965,803
Current liabilities:
Accounts payable	1,737,247	2,623,010
Accrued liabilities	3,887,511	4,491,164
Deferred revenue	8,101,667	8,751,336
Warrants	16,357,444	19,787,007
Total current liabilities	30,083,869	35,652,517
Long-term deferred revenue	377,076	522,329
Other liabilities	321,316	320,409
Total liabilities	30,782,261	36,495,255
Convertible Preferred stock:
Convertible Preferred stock, par value $0.001; 10,000,000 shares authorized ; 23,900 shares outstanding at 2017 and 2016	5,960,475	5,960,475
Stockholders' deficit:
Common stock, par value $0.001; 300,000,000 shares authorized, 22,612,043 and 22,063,582 shares issued at 2017 and 2016, respectively	22,612	22,064
Additional paid in capital	450,370,408	449,939,406
Treasury stock, 4,015 shares at 2017 and 2016	(205,999)	(205,999)
Accumulated deficit	(470,245,729)	(471,245,398)
Total stockholders' deficit	(20,058,708)	(21,489,927)
Total liabilities and stockholders' deficit	$ 16,684,028	$ 20,965,803