Condensed Consolidated Statements of Convertible Preferred Stock and Stockholders’ Deficit - USD ($)	Common Stock	Additional Paid-in capital	Accumulated other comprehensive loss	Accumulated deficit	Series A convertible preferred stock	Series B convertible preferred stock	Series C convertible preferred stock	Total
Temporary equity, beginning balance at Dec. 31, 2018					$ 6,483,044	$ 49,742,942	$ 56,364,645
Temporary Equity, Beginning Balance (in shares) at Dec. 31, 2018					612,446	7,235,969	4,712,698
Increase (Decrease) in Temporary Equity
Issuance of convertible preferred stock, net of issuance costs							$ 5,598,362
Issuance of convertible preferred stock (in shares)							467,179
Temporary equity, ending balance at Mar. 31, 2019					$ 6,483,044	$ 49,742,942	$ 61,963,007
Temporary Equity, Ending Balance (in shares) at Mar. 31, 2019					612,446	7,235,969	5,179,877
Equity, beginning balance at Dec. 31, 2018	$ 127,091	$ 19,666,588	$ (8,761,325)	$ (62,468,456)				$ (51,436,102)
Equity, beginning balance (in shares) at Dec. 31, 2018	1,155,366
Increase (Decrease) in Stockholders' Equity
Exercise of stock options	$ 2,883	20,235						23,118
Exercise of stock options (in shares)	26,207
Stock‑based compensation		97,946						97,946
Foreign currency translation			(2,031,175)					(2,031,175)
Net loss				(3,475,202)				(3,475,202)
Equity, ending balance at Mar. 31, 2019	$ 129,974	19,784,769	(10,792,500)	(65,943,658)				(56,821,415)
Equity, ending balance (in shares) at Mar. 31, 2019	1,181,573
Temporary equity, beginning balance at Dec. 31, 2018					$ 6,483,044	$ 49,742,942	$ 56,364,645
Temporary Equity, Beginning Balance (in shares) at Dec. 31, 2018					612,446	7,235,969	4,712,698
Temporary equity, ending balance at Jun. 30, 2019					$ 6,483,044	$ 49,742,942	$ 61,963,007
Temporary Equity, Ending Balance (in shares) at Jun. 30, 2019					612,446	7,235,969	5,179,877
Equity, beginning balance at Dec. 31, 2018	$ 127,091	19,666,588	(8,761,325)	(62,468,456)				(51,436,102)
Equity, beginning balance (in shares) at Dec. 31, 2018	1,155,366
Increase (Decrease) in Stockholders' Equity
Foreign currency translation								(1,986,667)
Net loss								(8,737,650)
Equity, ending balance at Jun. 30, 2019	$ 129,974	19,971,732	(10,747,992)	(71,206,106)				(61,852,392)
Equity, ending balance (in shares) at Jun. 30, 2019	1,181,573
Temporary equity, beginning balance at Mar. 31, 2019					$ 6,483,044	$ 49,742,942	$ 61,963,007
Temporary Equity, Beginning Balance (in shares) at Mar. 31, 2019					612,446	7,235,969	5,179,877
Temporary equity, ending balance at Jun. 30, 2019					$ 6,483,044	$ 49,742,942	$ 61,963,007
Temporary Equity, Ending Balance (in shares) at Jun. 30, 2019					612,446	7,235,969	5,179,877
Equity, beginning balance at Mar. 31, 2019	$ 129,974	19,784,769	(10,792,500)	(65,943,658)				(56,821,415)
Equity, beginning balance (in shares) at Mar. 31, 2019	1,181,573
Increase (Decrease) in Stockholders' Equity
Stock‑based compensation		186,963						186,963
Foreign currency translation			44,508					44,508
Net loss				(5,262,448)				(5,262,448)
Equity, ending balance at Jun. 30, 2019	$ 129,974	19,971,732	(10,747,992)	(71,206,106)				(61,852,392)
Equity, ending balance (in shares) at Jun. 30, 2019	1,181,573
Equity, beginning balance at Dec. 31, 2019	$ 21,023	226,284,548	(11,533,778)	(90,528,263)				124,243,530
Equity, beginning balance (in shares) at Dec. 31, 2019	21,022,752
Increase (Decrease) in Stockholders' Equity
Exercise of stock options	$ 32	29,491						29,523
Exercise of stock options (in shares)	32,090
Stock‑based compensation		905,471						905,471
Foreign currency translation			(2,424,653)					(2,424,653)
Net loss				(9,400,257)				(9,400,257)
Equity, ending balance at Mar. 31, 2020	$ 21,055	227,219,510	(13,958,431)	(99,928,520)				113,353,614
Equity, ending balance (in shares) at Mar. 31, 2020	21,054,842
Equity, beginning balance at Dec. 31, 2019	$ 21,023	226,284,548	(11,533,778)	(90,528,263)				124,243,530
Equity, beginning balance (in shares) at Dec. 31, 2019	21,022,752
Increase (Decrease) in Stockholders' Equity
Foreign currency translation								(667,870)
Net loss								(25,768,184)
Equity, ending balance at Jun. 30, 2020	$ 21,187	228,597,264	(12,201,648)	(116,296,447)				100,120,356
Equity, ending balance (in shares) at Jun. 30, 2020	21,186,827
Equity, beginning balance at Mar. 31, 2020	$ 21,055	227,219,510	(13,958,431)	(99,928,520)				113,353,614
Equity, beginning balance (in shares) at Mar. 31, 2020	21,054,842
Increase (Decrease) in Stockholders' Equity
Exercise of stock options	$ 132	121,294						121,426
Exercise of stock options (in shares)	131,985
Stock‑based compensation		1,256,460						1,256,460
Foreign currency translation			1,756,783					1,756,783
Net loss				(16,367,927)				(16,367,927)
Equity, ending balance at Jun. 30, 2020	$ 21,187	$ 228,597,264	$ (12,201,648)	$ (116,296,447)				$ 100,120,356
Equity, ending balance (in shares) at Jun. 30, 2020	21,186,827