Condensed Statements of Cash Flows (Unaudited) - USD ($)		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017
Statement Of Cash Flows [Abstract]
Net loss		$ (4,974,963)	$ (8,938,254)
Adjustments to reconcile net loss to net cash used in operations:
Depreciation		28,900	4,546
Stock-based compensation		492,080	295,418
Amortization of debt discount			17,765
Debt discount on convertible notes			5,172,000
Excess and obsolete inventory reserve		28,887	36,028
Common stock issued for services			30,000
Change in fair value of derivative liabilities		(17,968)	155,008
Changes in operating assets and liabilities:
Accounts receivable		(87,912)	(139,525)
Inventories		(109,498)	(76,621)
Prepaid expenses and other		(74,507)	(121,633)
Accounts payable and other accrued expenses		122,099	594,339
Accrued interest			209,627
Deferred revenue		(17,466)	14,297
Net cash used in operating activities		(4,610,348)	(2,747,005)
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of equipment		(81,457)	(4,987)
Net cash used in investing activities		(81,457)	(4,987)
CASH FLOWS FROM FINANCING ACTIVITIES
Payments of issuance costs		(49,042)
Net settlement of vested restricted stock units to fund related employee statutory tax withholding		(68,190)
Proceeds from exercise of stock options		2	2,982
Proceeds from exercise of warrants		3,556,391
Proceeds from IPO, net of offering costs	[1]		4,423,315
Proceeds from private placement, net of offering costs			2,922,885
Proceeds from convertible promissory notes, net			1,770,000
Repayment of note payable, MLSC			(54,123)
Net cash provided by financing activities		3,439,161	9,065,059
Net (decrease) increase in cash, cash equivalents and restricted cash		(1,252,644)	6,313,067
Cash, cash equivalents and restricted cash, beginning of period		13,011,373	849,174
Cash, cash equivalents and restricted cash, end of period		11,758,729	7,162,241
SUPPLEMENTAL DISCLOSURE CASH FLOW INFORMATION
Cash paid during the period for interest			59,536
SUPPLEMENTAL DISCLOSURE OF NON-CASH INVESTING AND FINANCING ACTIVITIES
Inventory capitalized as sales demo equipment		$ 34,142
Exchange of 2015 convertible promissory notes for 2016 convertible promissory notes			430,000
Accretion of convertible preferred stock to redemption value			274,011
Conversion of accrued interest to principal			21,916
Conversion of convertible preferred stock into common stock			12,946,252
Conversion of convertible promissory notes and accrued interest into common stock			5,467,389
Issuance of selling agent warrants in connection with IPO			156,725
Deferred offering costs to additional paid-in capital upon IPO closing	[1]		438,237
IPO issuance costs included in accounts payable and accrued expense			$ 31,930

[1] IPO gross proceeds of $4,991,236 are reduced by $567,921 of IPO offering costs that were incurred in 2017. Another $438,237 of IPO deferred offering costs were paid for in 2016.