Consolidated Statements of changes in Stockholders' Equity - USD ($)	Total	Market Offering [Member]	Registered Direct Offering [Member]	Common Stock [Member]	Common Stock [Member] Market Offering [Member]	Common Stock [Member] Registered Direct Offering [Member]	Additional Paid-In Capital [Member]	Additional Paid-In Capital [Member] Market Offering [Member]	Additional Paid-In Capital [Member] Registered Direct Offering [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss [Member]
Beginning Balance at Dec. 31, 2018	$ 48,312,566			$ 876			$ 170,207,844			$ (116,855,991)	$ (5,040,163)
Beginning Balance (in shares) at Dec. 31, 2018				9,078,238
Stock-based compensation	407,714						407,714
Vesting of restricted stock awards including withholding, net	28						28
Vesting of restricted stock awards including withholding, net (in shares)				71
Issuance of common stock, net			$ 12,668,784			$ 436			$ 12,668,348
Issuance of common stock, net (in shares)						4,361,370
Issuance of common stock upon exercise of warrants	30,324			$ 1			30,323
Issuance of common stock upon exercise of warrants (in shares)				11,000
Net loss	(2,097,306)									(2,097,306)
Ending Balance at Mar. 31, 2019	59,322,110			$ 1,313			183,314,257			(118,953,297)	(5,040,163)
Ending Balance (in shares) at Mar. 31, 2019				13,450,679
Beginning Balance at Dec. 31, 2018	48,312,566			$ 876			170,207,844			(116,855,991)	(5,040,163)
Beginning Balance (in shares) at Dec. 31, 2018				9,078,238
Unrealized (loss) gain on short-term investments	18,953
Net loss	(16,423,506)
Ending Balance at Sep. 30, 2019	49,383,950			$ 1,502			187,683,155			(133,279,497)	(5,021,210)
Ending Balance (in shares) at Sep. 30, 2019				15,338,072
Beginning Balance at Mar. 31, 2019	59,322,110			$ 1,313			183,314,257			(118,953,297)	(5,040,163)
Beginning Balance (in shares) at Mar. 31, 2019				13,450,679
Stock-based compensation	289,772						289,772
Vesting of restricted stock awards including withholding, net	28						28
Vesting of restricted stock awards including withholding, net (in shares)				71
Net loss	(3,386,888)									(3,386,888)
Ending Balance at Jun. 30, 2019	56,225,022			$ 1,313			183,604,057			(122,340,185)	(5,040,163)
Ending Balance (in shares) at Jun. 30, 2019				13,450,750
Stock-based compensation	287,774						287,774
Vesting of restricted stock awards including withholding, net	28						28
Vesting of restricted stock awards including withholding, net (in shares)				72
Issuance of common stock for acquired in-process research and development	3,791,485			$ 189			3,791,296
Issuance of common stock for acquired in-process research and development (in shares)				1,887,250
Unrealized (loss) gain on short-term investments	18,953										18,953
Net loss	(10,939,312)									(10,939,312)
Ending Balance at Sep. 30, 2019	49,383,950			$ 1,502			187,683,155			(133,279,497)	(5,021,210)
Ending Balance (in shares) at Sep. 30, 2019				15,338,072
Beginning Balance at Dec. 31, 2019	45,520,146			$ 1,508			187,914,916			(137,376,122)	(5,020,156)
Beginning Balance (in shares) at Dec. 31, 2019				15,312,167
Stock-based compensation	214,921						214,921
Vesting of restricted stock awards including withholding, net	(17,079)			$ 1			(17,080)
Vesting of restricted stock awards including withholding, net (in shares)				(5,974)
Issuance of common stock from Employee Stock Purchase Plan	56,739			$ 3			56,736
Issuance of common stock from Employee Stock Purchase Plan (in shares)				38,809
Issuance of common stock upon exercise of warrants	39,974			$ 2			39,972
Issuance of common stock upon exercise of warrants (in shares)				14,500
Unrealized (loss) gain on short-term investments	(32,435)										(32,435)
Net loss	(3,885,649)									(3,885,649)
Ending Balance at Mar. 31, 2020	41,896,617			$ 1,514			188,209,465			(141,261,771)	(5,052,591)
Ending Balance (in shares) at Mar. 31, 2020				15,359,502
Beginning Balance at Dec. 31, 2019	45,520,146			$ 1,508			187,914,916			(137,376,122)	(5,020,156)
Beginning Balance (in shares) at Dec. 31, 2019				15,312,167
Unrealized (loss) gain on short-term investments	(22,116)
Net loss	(38,422,700)
Ending Balance at Sep. 30, 2020	199,705,835			$ 3,289			380,543,640			(175,798,822)	(5,042,272)
Ending Balance (in shares) at Sep. 30, 2020				33,073,035
Beginning Balance at Mar. 31, 2020	41,896,617			$ 1,514			188,209,465			(141,261,771)	(5,052,591)
Beginning Balance (in shares) at Mar. 31, 2020				15,359,502
Stock-based compensation	330,510						330,510
Issuance of common stock from exercise of stock options	36,175			$ 1			36,174
Issuance of common stock from exercise of stock options (in shares)				13,935
Vesting of restricted stock awards including withholding, net	(46,389)			$ 1			(46,390)
Vesting of restricted stock awards including withholding, net (in shares)				(5,974)
Issuance of common stock, net		$ 22,780,729			$ 297			$ 22,780,432
Issuance of common stock, net (in shares)					2,965,144
Issuance of common stock upon exercise of warrants	31,270,163			$ 822			31,269,341
Issuance of common stock upon exercise of warrants (in shares)				8,221,279
Unrealized (loss) gain on short-term investments	20,888										20,888
Net loss	(16,766,916)									(16,766,916)
Ending Balance at Jun. 30, 2020	79,521,777			$ 2,635			242,579,532			(158,028,687)	(5,031,703)
Ending Balance (in shares) at Jun. 30, 2020				26,553,886
Stock-based compensation	1,320,089						1,320,089
Issuance of common stock from exercise of stock options	90,270			$ 3			90,267
Issuance of common stock from exercise of stock options (in shares)				32,189
Vesting of restricted stock awards including withholding, net	(114,572)			$ 13			(114,585)
Vesting of restricted stock awards including withholding, net (in shares)				103,551
Issuance of common stock from Employee Stock Purchase Plan	78,732			$ 5			78,727
Issuance of common stock from Employee Stock Purchase Plan (in shares)				53,852
Issuance of common stock and pre-funded warrants in public offering, net	124,027,815			$ 412			124,027,403
Issuance of common stock and pre-funded warrants in public offering, net (in shares)				4,119,564
Issuance of common stock, net		$ 2,834,107			$ 25			$ 2,834,082
Issuance of common stock, net (in shares)					247,865
Issuance of common stock upon exercise of warrants	9,728,321			$ 196			9,728,125
Issuance of common stock upon exercise of warrants (in shares)				1,962,128
Unrealized (loss) gain on short-term investments	(10,569)										(10,569)
Net loss	(17,770,135)									(17,770,135)
Ending Balance at Sep. 30, 2020	$ 199,705,835			$ 3,289			$ 380,543,640			$ (175,798,822)	$ (5,042,272)
Ending Balance (in shares) at Sep. 30, 2020				33,073,035