Condensed Consolidated Statements of Changes in Stockholders' Equity - USD ($)	Total	LP Purchase Agreement	ATM Offering	Private Placement	Series A Convertible Preferred Stock	Series A Convertible Preferred Stock Private Placement	Common Stock	Common Stock LP Purchase Agreement	Common Stock ATM Offering	Additional Paid-In Capital	Additional Paid-In Capital LP Purchase Agreement	Additional Paid-In Capital ATM Offering	Additional Paid-In Capital Private Placement	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balance at Dec. 31, 2018	$ 21,092,062						$ 28,585			$ 172,086,909				$ (3,453)	$ (151,019,979)
Balance, shares at Dec. 31, 2018							28,585,449
Exercise of stock options	51,570						$ 22			51,548
Exercise of stock options, shares							21,871
Stock-based compensation expense	241,233									241,233
Release of restricted stock awards	13						$ 13
Release of restricted stock awards, shares							13,126
Net share settlement of restricted stock award	(9,685)						$ (4)			(9,681)
Net share settlement of restricted stock award, shares							(3,813)
Employee stock purchase plan expense	16,794									16,794
Net loss	(5,370,846)														(5,370,846)
Unrealized gain on short-term investments	3,353													3,353
Foreign currency translation adjustment	6,439													6,439
Balance at Mar. 31, 2019	16,030,933						$ 28,616			172,386,803				6,339	(156,390,825)
Balance, shares at Mar. 31, 2019							28,616,633
Balance at Dec. 31, 2019	23,969,634						$ 58,090			194,234,151				(4,964)	(170,317,643)
Balance, shares at Dec. 31, 2019							58,090,233
Stock-based compensation expense	415,256									415,256
Release of restricted stock awards	36						$ 36
Release of restricted stock awards, shares							35,942
Net share settlement of restricted stock award	(7,052)						$ (11)			(7,041)
Net share settlement of restricted stock award, shares							(11,266)
Employee stock purchase plan expense	5,379									5,379
Issuance of common stock			$ 2,435,912					$ 615	$ 4,399		$ (615)	$ 2,431,513
Issuance of common stock, shares							4,399,062	615,384	4,399,062
Issuance of preferred stock	2,424,900			$ 562,955	$ 41	$ 10				2,424,859			$ 562,945
Issuance of preferred stock, shares					41,100	10,170
Cancellation of common stock received in exchange for Series A convertible preferred stock	(2,424,900)						$ (4,110)			(2,420,790)
Cancellation of common stock received in exchange for Series A convertible preferred stock, shares							(4,110,000)
Exercise of pre-funded warrants	31,768						$ 3,177			28,591
Exercise of pre-funded warrants, shares							3,176,762
Transaction costs incurred in connection with LP Purchase Agreement		$ (96,000)									$ (96,000)
Net loss	(5,457,898)														(5,457,898)
Unrealized gain on short-term investments	47,697													47,697
Foreign currency translation adjustment	5,497													5,497
Balance at Mar. 31, 2020	$ 21,913,184				$ 51		$ 62,196			$ 197,578,248				$ 48,230	$ (175,775,541)
Balance, shares at Mar. 31, 2020					51,270		62,196,117