CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS’ EQUITY - USD ($)	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Loss
Balance (in shares) at Dec. 31, 2017		71,915,018
Balance at Dec. 31, 2017	$ 185,540,560	$ 71,918	$ 408,029,068	$ (221,435,888)	$ (1,124,538)
Increase (Decrease) in Stockholders' Equity
Stock-based compensation expense	4,259,795		4,259,795
Exercise of stock options (in shares)		131,051
Exercise of stock options	232,416	$ 131	232,285
Issuance of common stock for vested RSAs (in shares)		1,075,893
Issuance of common stock for vested RSAs	0	$ 1,069	(1,069)
RSAs withheld to cover taxes	(306,120)		(306,120)
Other comprehensive loss	(540,807)				(540,807)
Net income	(4,447,933)			(4,447,933)
Balance (in shares) at Jun. 30, 2018		73,121,962
Balance at Jun. 30, 2018	184,754,386	$ 73,118	412,213,959	(225,867,346)	(1,665,345)
Balance (in shares) at Dec. 31, 2017		71,915,018
Balance at Dec. 31, 2017	$ 185,540,560	$ 71,918	408,029,068	(221,435,888)	(1,124,538)
Increase (Decrease) in Stockholders' Equity
Exercise of stock options (in shares)	1,079,496
Balance (in shares) at Dec. 31, 2018		74,697,526
Balance at Dec. 31, 2018	$ 197,220,826	$ 74,700	419,455,818	(220,276,025)	(2,033,667)
Balance (in shares) at Mar. 31, 2018		72,106,997
Balance at Mar. 31, 2018	183,806,069	$ 72,104	410,105,207	(225,632,074)	(739,168)
Increase (Decrease) in Stockholders' Equity
Stock-based compensation expense	2,090,870		2,090,870
Exercise of stock options (in shares)		131,051
Exercise of stock options	232,416	$ 131	232,285
Issuance of common stock for vested RSAs (in shares)		883,914
Issuance of common stock for vested RSAs	0	$ 883	(883)
RSAs withheld to cover taxes	(213,520)		(213,520)
Other comprehensive loss	(926,177)				(926,177)
Net income	(235,272)			(235,272)
Balance (in shares) at Jun. 30, 2018		73,121,962
Balance at Jun. 30, 2018	184,754,386	$ 73,118	412,213,959	(225,867,346)	(1,665,345)
Balance (in shares) at Dec. 31, 2018		74,697,526
Balance at Dec. 31, 2018	197,220,826	$ 74,700	419,455,818	(220,276,025)	(2,033,667)
Increase (Decrease) in Stockholders' Equity
Stock-based compensation expense	$ 5,290,053		5,290,053
Exercise of stock options (in shares)	157,334	157,334
Exercise of stock options	$ 702,717	$ 156	702,561
Issuance of common stock for vested RSAs (in shares)		1,372,723
Issuance of common stock for vested RSAs	0	$ 1,372	(1,372)
RSAs withheld to cover taxes	(371,316)		(371,316)
Other comprehensive loss	94,540				94,540
Net income	3,461,425			3,461,425
Balance (in shares) at Jun. 30, 2019		76,227,583
Balance at Jun. 30, 2019	206,398,245	$ 76,228	425,075,744	(216,814,600)	(1,939,127)
Balance (in shares) at Mar. 31, 2019		75,270,035
Balance at Mar. 31, 2019	201,225,781	$ 75,272	422,471,569	(219,018,426)	(2,302,634)
Increase (Decrease) in Stockholders' Equity
Stock-based compensation expense	2,865,336		2,865,336
Exercise of stock options (in shares)		5,597
Exercise of stock options	21,728	$ 4	21,724
Issuance of common stock for vested RSAs (in shares)		951,951
Issuance of common stock for vested RSAs	0	$ 952	(952)
RSAs withheld to cover taxes	(281,933)		(281,933)
Other comprehensive loss	363,507				363,507
Net income	2,203,826			2,203,826
Balance (in shares) at Jun. 30, 2019		76,227,583
Balance at Jun. 30, 2019	$ 206,398,245	$ 76,228	$ 425,075,744	$ (216,814,600)	$ (1,939,127)