Condensed Consolidated Statements of Cash Flows - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Cash flows from operating activities
Net loss	$ (3,853,116)	$ (3,048,084)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation and amortization	223,115	156,335
Noncash interest expense	29,265	49,133
Stock compensation expense	98,033	238,190
Loss (gain) on sale of equipment	24,439	(5,253)
Change in fair value of warrant liability	(67)	(8,166)
Impairment of right-of-use asset	520,759	0
Changes in operating assets and liabilities:
Accounts receivable	(440,475)	218,746
Inventory	44,545	24,882
Other assets	285,070	80,197
Accounts payable	(31,531)	(63,048)
Accrued compensation and other liabilities	120,015	126,439
Deferred revenue	(5,831)	(1,402)
Net cash used in operating activities	(2,985,779)	(2,232,031)
Cash flows from investing activities
Purchases of property and equipment	(8,493)	0
Proceeds from sale of equipment	1,250	10,440
Net cash (used in) provided by investing activities	(7,243)	10,440
Cash flows from financing activities
Proceeds from issuance of common stock, net of issuance costs	4,782,509	0
Proceeds from issuance of units, net of selling costs	0	10,721,401
Payments on debt	(217,484)	(48,424)
Payments on finance leases	(116,538)	(50,193)
Net cash provided by financing activities	4,448,487	10,622,784
Effects of exchange rates on cash	4,216	(13,522)
Net increase in cash, cash equivalents and restricted cash	1,459,681	8,387,671
Cash, cash equivalents and restricted cash at beginning of period	4,737,207	2,090,551	$ 2,090,551
Cash, cash equivalents and restricted cash at end of period	6,196,888	10,478,222	$ 4,737,207
Supplemental disclosure of cash flow information
Cash paid for interest	73,754	8,713
Supplemental disclosures of noncash investing and financing activities:
Right-of-use assets acquired through finance leases	161,116	87,512
Conversion of accounts payable to finance lease	$ 63,600	$ 174,968