CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net loss	$ (17,211,179)	$ (8,460,799)	$ (11,763,456)
Adjustments to reconcile net loss to net cash used by operating activities:
Non-cash interest expense	637,000	0	0
Non-cash compensation	947,910	691,480	431,352
Depreciation and amortization	390,551	218,271	161,613
Bad debt expense	14,762	904	65,378
Foreign currency transaction (gains) losses	784,752	(1,454,136)	358,077
Stock-based compensation	4,437,250	3,313,603	2,756,793
Amortization of loan acquisition costs	97,041	82,054	30,480
Changes in operating assets and liabilities:
Grants and accounts receivable	(1,847,848)	(649,318)	(889,715)
Inventories	(56,751)	57,320	340,392
Prepaid expenses and other current assets	(731,672)	(76,981)	187,099
Other assets	(6,345)	(15,000)	(41,112)
Accounts payable and accrued expenses	1,704,845	(168,103)	1,632,132
Net cash used by operating activities	(10,839,684)	(6,460,705)	(6,730,967)
Cash flows from investing activities:
Purchases of property and equipment	(671,970)	(990,673)	(140,724)
Patent costs	(848,294)	(687,446)	(454,807)
Proceeds from sale of short-term investments	0	0	2,192,000
Net cash provided/(used) by investing activities	(1,520,264)	(1,678,119)	1,596,469
Cash flows from financing activities:
Proceeds from long-term debt	666,667	5,000,000	5,000,000
Repayment of long-term debt	(666,667)	0	0
Payment of loan acquisition costs	(147,988)	(1,560)	(118,833)
Equity contributions - net of fees incurred	14,126,525	13,679,730	0
Proceeds from exercise of stock options	2,206,860	591,899	118,040
Proceeds from exercise of warrants	1,280,456	853,004	65,000
Net cash provided by financing activities	17,465,853	20,123,073	5,064,207
Effect of exchange rates on cash	(58,930)	92,435	(1,382)
Net change in cash and cash equivalents	5,046,975	12,076,684	(71,673)
Cash and cash equivalents at beginning of year	17,321,862	5,245,178	5,316,851
Cash and cash equivalents at end of year	22,368,837	17,321,862	5,245,178
Supplemental disclosure of cash flow information:
Cash paid during the year for interest	891,386	634,608	175,897
Supplemental disclosure of non-cash financing activities:
Settlement of accrued bonuses with restricted stock units	545,693	207,608	0
Dividend, warrant exercise price adjustment	$ 0	$ 335,731	$ 0