Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Operating activities:
Net loss				$ (15,516,309)	$ (7,158,838)
Adjustments to reconcile net loss to net cash used by operating activities:
Depreciation	$ 266,963	$ 387,104		536,802	778,555
Change in fair value of preferred stock warrants and expirations	0	(1,517,723)		0	(2,470,921)
Interest payment-in-kind				166,524	0
Stock-based compensation				625,061	107,426
Provision for bad debt expense				0	238,000
Accretion of debt discount				128,518	60,655
Loss on debt extinguishment	0	342,164		921,496	342,164
Long-term debt prepayment fees			$ 0	412,000
Employee stock purchase plan compensation				102,815	0
Changes in operating assets and liabilities:
Accounts receivable				(469,177)	228,009
Inventory				(1,953,533)	(172,578)
Prepaid expenses and other current assets				287,647	(697,361)
Accounts payable				2,257,359	(1,058,391)
Accrued expenses and other liabilities				(367,628)	49,359
Net cash used in operating activities				(12,868,425)	(9,753,921)	$ 19,900,000
Investing activities:
Purchases of property and equipment				(29,649)	(189,401)
Net cash used in investing activities				(29,649)	(189,401)
Financing activities:
Repayment of long-term debt				(10,812,000)	(7,447,571)
Proceeds from issuance of long-term debt, net of issuance costs				19,207,403	9,662,430
Proceeds from issuance of convertible note, net of issuance costs				0	14,329,843
Proceeds from borrowing on line of credit				1,105,745	0
Repayments of borrowing from line of credit				(305,930)	0
Proceeds from sale of common stock, net of offering costs				2,409,593	0
Proceeds from option exercises				65,060	1,012
Net cash provided by financing activities				11,669,871	16,545,714
Net (decrease) increase in cash and cash equivalents				(1,228,203)	6,602,392
Cash and cash equivalents at beginning of period			$ 1,021,897	16,522,729	1,021,897	1,021,897
Cash and cash equivalents at end of period	$ 15,294,526	$ 7,624,289		15,294,526	7,624,289	$ 16,522,729
Supplemental schedule on non-cash transactions:
Property and equipment costs incurred but not paid included in accounts payable and accrued expenses				8,740	130,484
Transfer of instruments from property and equipment into inventory				0	106,617
Fair value of warrants issued with debt classified as a liability				629,830	176,813
Fair value of stock issued with debt classified as a liability				201,789	0
Final payment due in connection with the repayment of debt classified in other long-term liabilities				0	400,000
Deferred equity issuance costs in accounts payable and accrued liabilities				0	1,401,350
Debt issuance costs incurred but not paid				$ 0	$ 129,474