Condensed Statements of Cash Flows (Unaudited) - USD ($)	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (7,951,505)	$ (7,624,785)
Adjustments to reconcile net loss to net cash used in operations:
Depreciation	70,678	48,833
Stock-based compensation	740,304	642,961
Excess and obsolete inventory reserve		26,645
Change in fair value of derivative liabilities	(155,955)	(31,278)
Loss on disposal of asset	2,481
Other non-cash charges	14,634	(16,275)
Changes in operating assets and liabilities:
Accounts receivable	248,252	(39,510)
Inventories	(302,608)	(151,332)
Prepaid expenses and other	(130,268)	(332,591)
Other assets	(2,000)
Accounts payable and other accrued expenses	(191,120)	413,317
Deferred revenue	2,447	(29,284)
Customer advance payments	(43,042)
Net cash used in operating activities	(7,697,702)	(7,093,299)
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of equipment	(38,261)	(117,370)
Net cash used in investing activities	(38,261)	(117,370)
CASH FLOWS FROM FINANCING ACTIVITIES
Payments of issuance costs		(117,273)
Net settlement of vested restricted stock units to fund related employee statutory tax withholding	(80,321)	(71,412)
Proceeds from exercise of stock options	16	2
Proceeds from exercise of warrants		3,556,391
Proceeds from public offering	5,603,829
Net cash provided by financing activities	5,523,524	3,367,708
Net decrease in cash, cash equivalents and restricted cash	(2,212,439)	(3,842,961)
Cash, cash equivalents and restricted cash, beginning of period	6,615,794	13,011,373
Cash, cash equivalents and restricted cash, end of period	4,403,355	9,168,412
SUPPLEMENTAL DISCLOSURE CASH FLOW INFORMATION
Inventory capitalized as sales demo equipment	17,715	$ 53,178
Issuance of warrants recorded as a derivative liability	$ 196,236