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, 2019	$ 23,969,634						$ 3,873			$ 194,288,368				$ (4,964)	$ (170,317,643)
Balance, shares at Dec. 31, 2019							3,872,682
Stock-based compensation expense	415,256									415,256
Release of restricted stock awards	36						$ 2			34
Release of restricted stock awards, shares							2,396
Net share settlement of restricted stock awards	(7,052)						$ (1)			(7,051)
Net share settlement of restricted stock award, shares							(751)
Employee stock purchase plan expense	5,379									5,379
Issuance of common stock			$ 2,435,912					$ 41	$ 293		$ (41)	$ 2,435,619
Issuance of common stock, shares								41,026	293,271
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)						$ (274)			(2,424,626)
Cancellation of common stock received in exchange for Series A convertible preferred stock, shares							(274,000)
Exercise of pre-funded warrants	31,768						$ 212			31,556
Exercise of pre-funded warrants, shares							211,784
Adjustment in connection with LP Purchase Agreement commitment fee and transaction costs		$ (96,000)									(96,000)
Net loss	(5,457,898)														(5,457,898)
Unrealized gain (loss) 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		$ 4,146			197,636,298				48,230	(175,775,541)
Balance, shares at Mar. 31, 2020					51,270		4,146,408
Balance at Dec. 31, 2019	23,969,634						$ 3,873			194,288,368				(4,964)	(170,317,643)
Balance, shares at Dec. 31, 2019							3,872,682
Net loss	(16,580,237)
Unrealized gain (loss) on short-term investments	4,060
Balance at Sep. 30, 2020	16,201,354				$ 24		$ 4,739			203,087,744				6,727	(186,897,880)
Balance, shares at Sep. 30, 2020					23,770		4,738,597
Balance at Mar. 31, 2020	21,913,184				$ 51		$ 4,146			197,636,298				48,230	(175,775,541)
Balance, shares at Mar. 31, 2020					51,270		4,146,408
Stock-based compensation expense	361,477									361,477
Release of restricted stock awards	24						$ 2			22
Release of restricted stock awards, shares							1,583
Net share settlement of restricted stock awards	(2,108)									(2,108)
Net share settlement of restricted stock award, shares							(426)
Stock issued under stock purchase plans	30,512						$ 3			30,509
Stock issued under stock purchase plans, shares							3,033
Issuance of common stock			1,395,058						$ 139			1,394,919
Issuance of common stock, shares									138,981
Conversion of Series A convertible preferred stock for common stock					$ (27)		$ 183			(156)
Conversion of Series A convertible preferred stock for common stock, shares					(27,500)		183,333
Adjustment in connection with LP Purchase Agreement commitment fee and transaction costs		301,538									301,538
Issuance of common stock warrants in connection with SVB Term Loan	420,000									420,000
Net loss	(5,710,551)														(5,710,551)
Unrealized gain (loss) on short-term investments	(26,136)													(26,136)
Foreign currency translation adjustment	909													909
Balance at Jun. 30, 2020	18,683,907				$ 24		$ 4,473			200,142,499				23,003	(181,486,092)
Balance, shares at Jun. 30, 2020					23,770		4,472,912
Stock-based compensation expense	386,911									386,911
Release of restricted stock awards	38						$ 3			35
Release of restricted stock awards, shares							2,542
Net share settlement of restricted stock awards	(3,664)									(3,664)
Net share settlement of restricted stock award, shares							(339)
Employee stock purchase plan expense	5,214									5,214
Issuance of common stock			2,557,012						$ 263			2,556,749
Issuance of common stock, shares									263,482
Net loss	(5,411,788)														(5,411,788)
Unrealized gain (loss) on short-term investments	(17,501)													(17,501)
Foreign currency translation adjustment	1,225													1,225
Balance at Sep. 30, 2020	16,201,354				$ 24		$ 4,739			203,087,744				6,727	(186,897,880)
Balance, shares at Sep. 30, 2020					23,770		4,738,597
Balance at Dec. 31, 2020	14,484,660				$ 24		$ 5,200			205,661,999				5,298	(191,187,861)
Balance, shares at Dec. 31, 2020					23,770		5,199,997
Stock-based compensation expense	337,823									337,823
Release of restricted stock awards	1						$ 1
Release of restricted stock awards, shares							1,390
Net share settlement of restricted stock awards	(1,197)									(1,197)
Net share settlement of restricted stock award, shares							(250)
Employee stock purchase plan expense	13,115									13,115
Issuance of common stock			6,855,198						$ 1,058			6,854,140
Issuance of common stock, shares									1,058,045
Exercise of stock options	326									326
Exercise of stock options, shares							75
Net loss	(4,848,307)														(4,848,307)
Foreign currency translation adjustment	(1,557)													(1,557)
Balance at Mar. 31, 2021	16,840,062				$ 24		$ 6,259			212,866,206				3,741	(196,036,168)
Balance, shares at Mar. 31, 2021					23,770		6,259,257
Balance at Dec. 31, 2020	14,484,660				$ 24		$ 5,200			205,661,999				5,298	(191,187,861)
Balance, shares at Dec. 31, 2020					23,770		5,199,997
Issuance of common stock, shares									2,050,879
Conversion of Series A convertible preferred stock for common stock, shares							144,881
Net loss	(11,953,881)
Unrealized gain (loss) on short-term investments	0
Balance at Sep. 30, 2021	14,887,372				$ 24		$ 7,514			218,018,993				2,583	(203,141,742)
Balance, shares at Sep. 30, 2021					23,770		7,513,733
Balance at Mar. 31, 2021	16,840,062				$ 24		$ 6,259			212,866,206				3,741	(196,036,168)
Balance, shares at Mar. 31, 2021					23,770		6,259,257
Stock-based compensation expense	339,369									339,369
Release of restricted stock awards	1						$ 1
Release of restricted stock awards, shares							992
Net share settlement of restricted stock awards	(695)									(695)
Net share settlement of restricted stock award, shares							(127)
Employee stock purchase plan expense	13,116									13,116
Stock issued under stock purchase plans	53,437						$ 13			53,424
Stock issued under stock purchase plans, shares							13,637
Issuance of common stock			$ 3,810,621						$ 993			$ 3,809,628
Issuance of common stock, shares									992,834
Exercise of pre-funded warrants							$ 145			(145)
Exercise of pre-funded warrants, shares							144,881
Net loss	(2,614,952)														(2,614,952)
Foreign currency translation adjustment	(145)													(145)
Balance at Jun. 30, 2021	18,440,814				$ 24		$ 7,411			217,080,903				3,596	(198,651,120)
Balance, shares at Jun. 30, 2021					23,770		7,411,474
Stock-based compensation expense	323,172									323,172
Release of restricted stock awards	2						$ 2
Release of restricted stock awards, shares							1,158
Net share settlement of restricted stock awards	(679)									(679)
Net share settlement of restricted stock award, shares							(117)
Employee stock purchase plan expense	15,719									15,719
Issuance of common stock		$ 599,979						$ 101			$ 599,878
Issuance of common stock, shares								101,218
Net loss	(4,490,622)														(4,490,622)
Unrealized gain (loss) on short-term investments	0
Foreign currency translation adjustment	(1,013)													(1,013)
Balance at Sep. 30, 2021	$ 14,887,372				$ 24		$ 7,514			$ 218,018,993				$ 2,583	$ (203,141,742)
Balance, shares at Sep. 30, 2021					23,770		7,513,733