Balance Sheets - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 30,182,115	$ 10,796,072
Accounts receivable, net of allowance of $380,212 and $398,847 in 2019 and 2018, respectively	5,329,577	5,021,111
Inventories, net	1,847,530	1,191,666
Prepaid expenses and other current assets	1,470,922	963,700
Total current assets	38,830,144	17,972,549
Property and equipment, net	250,443	343,693
Operating lease right-of-use assets	4,286,064
Other assets	218,103	198,365
Total assets	43,584,754	18,514,607
Current liabilities:
Accounts payable	2,099,097	1,726,360
Accrued liabilities	2,721,104	2,642,481
Deferred revenue	5,092,455	5,825,536
Current portion of operating lease liabilities	2,248,189
Total current liabilities	12,160,845	10,194,377
Long-term deferred revenue	554,258	407,151
Operating lease liabilities	2,089,537
Other liabilities	255,517	641,461
Total liabilities	15,060,157	11,242,989
Series A - Convertible preferred stock:
Convertible preferred stock, Series A, par value $0.001; 23,110 and 23,900 shares outstanding at 2019 and 2018, respectively	5,758,190	5,960,475
Stockholders' equity:
Convertible preferred stock, Series B, par value $0.001; 10,000,000 shares authorized, 5,610,121 and no shares outstanding at 2019 and 2018, respectively	5,610
Common stock, par value $0.001; 300,000,000 shares authorized, 68,529,623 and 59,058,297 shares issued at 2019 and 2018, respectively	68,530	59,058
Additional paid in capital	504,211,040	478,179,574
Treasury stock, 4,015 shares at 2019 and 2018	(205,999)	(205,999)
Accumulated deficit	(481,312,774)	(476,721,490)
Total stockholders' equity	22,766,407	1,311,143
Total liabilities and stockholders' equity	$ 43,584,754	$ 18,514,607