Condensed Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) (Unaudited) - USD ($) $ in Thousands	Total	Cumulative Effect Adjustment of Accounting Method Change	Convertible notes	Private placement	Private placement LifeSci Capital LLC	Series C Convertible Preferred Stock	Series A Convertible Preferred Stock	Series B-1 Convertible Preferred Stock	Series B-2 Convertible Preferred Stock	Common stock	Common stock Convertible notes	Common stock Private placement	Common stock Private placement LifeSci Capital LLC	Additional paid-in capital	Additional paid-in capital Convertible notes	Additional paid-in capital Private placement	Additional paid-in capital Private placement LifeSci Capital LLC	Accumulated deficit	Accumulated deficit Cumulative Effect Adjustment of Accounting Method Change
Balance at Dec. 31, 2018	$ (5,355)	$ (45)								$ 1				$ 66,021				$ (71,377)	$ (45)
Balance, Shares at Dec. 31, 2018						1,524,122				4,411,567
Stock-based compensation	258													258
Net loss	(5,156)																	(5,156)
Balance at Mar. 31, 2019	(10,298)									$ 1				66,279				(76,578)
Balance, Shares at Mar. 31, 2019						1,524,122				4,411,567
Balance at Dec. 31, 2018	(5,355)	$ (45)								$ 1				66,021				(71,377)	$ (45)
Balance, Shares at Dec. 31, 2018						1,524,122				4,411,567
Net loss	(14,574)
Balance at Sep. 30, 2019	18,894									$ 1				104,889				(85,996)
Balance, Shares at Sep. 30, 2019							1,231			11,964,329
Balance at Mar. 31, 2019	(10,298)									$ 1				66,279				(76,578)
Balance, Shares at Mar. 31, 2019						1,524,122				4,411,567
Issuance of common stock from option exercises	41													41
Issuance of common stock from option exercises, Shares										37,264
Stock-based compensation	258													258
Net loss	(3,692)																	(3,692)
Balance at Jun. 30, 2019	(13,691)									$ 1				66,578				(80,270)
Balance, Shares at Jun. 30, 2019						1,524,122				4,448,831
Issuance of stock, net of issuance costs	718			$ 19,802										718		$ 19,802
Issuance of common and preferred stock, net of issuance costs, Shares							1,231			647,411		3,076,923
Issuance of common stock through conversion			$ 12,687												$ 12,687
Issuance of common stock through conversion, Shares						(1,524,122)				1,524,122	2,267,042
Additional paid in capital assumed in Business Combination	420													420
Issuance of Series A preferred stock at $3,250 per share	4,000													4,000
Stock-based compensation	684													684
Net loss	(5,726)																	(5,726)
Balance at Sep. 30, 2019	18,894									$ 1				104,889				(85,996)
Balance, Shares at Sep. 30, 2019							1,231			11,964,329
Balance at Dec. 31, 2019	12,489									$ 1				103,599				(91,111)
Balance, Shares at Dec. 31, 2019							1,231			12,344,818
Issuance of stock, net of issuance costs				$ 23,891												$ 23,891
Issuance of common and preferred stock, net of issuance costs, Shares								3,199	524			2,467,724
Issuance of Series B-1 convertible preferred stock	30,971													30,971
Issuance of Series B-2 convertible preferred stock	5,071													5,071
Issuance of common stock from option exercises	253													253
Issuance of common stock from option exercises, Shares										85,061
Issuance of common stock from warrant exercises	11													11
Issuance of common stock from warrant exercises, Shares										2,098
Issuance costs in connection with Form S-1 registration statement	(77)													(77)
Stock-based compensation	1,022													1,022
Net loss	(7,001)																	(7,001)
Balance at Mar. 31, 2020	66,630									$ 1				164,741				(98,112)
Balance, Shares at Mar. 31, 2020							1,231	3,199	524	14,899,701
Balance at Dec. 31, 2019	12,489									$ 1				103,599				(91,111)
Balance, Shares at Dec. 31, 2019							1,231			12,344,818
Net loss	(25,806)
Balance at Sep. 30, 2020	52,248									$ 2				169,163				(116,917)
Balance, Shares at Sep. 30, 2020										19,590,998
Balance at Mar. 31, 2020	66,630									$ 1				164,741				(98,112)
Balance, Shares at Mar. 31, 2020							1,231	3,199	524	14,899,701
Issuance of common stock through conversion	1									$ 1
Issuance of common stock through conversion, Shares								(3,199)		3,198,949
Issuance of common stock from option exercises and RSU releases	123													123
Issuance of common stock from option exercises and RSU releases, Shares										81,277
Issuance of common stock from warrant exercises	471													471
Issuance of common stock from warrant exercises, Shares										49,437
Issuance costs in connection with Form S-1 registration statement	(5)													(5)
Stock-based compensation	1,125													1,125
Net loss	(9,417)																	(9,417)
Balance at Jun. 30, 2020	58,928									$ 2				166,455				(107,529)
Balance, Shares at Jun. 30, 2020							1,231		524	18,229,364
Issuance of stock, net of issuance costs					$ 1,011												$ 1,011
Issuance of common and preferred stock, net of issuance costs, Shares													87,790
Issuance of common stock through conversion, Shares							(1,231)		(524)	1,139,199
Issuance of common stock from option exercises and RSU releases	24													24
Issuance of common stock from option exercises and RSU releases, Shares										102,641
Issuance of common stock from warrant exercises	300													300
Issuance of common stock from warrant exercises, Shares										32,004
Stock-based compensation	1,373													1,373
Net loss	(9,388)																	(9,388)
Balance at Sep. 30, 2020	$ 52,248									$ 2				$ 169,163				$ (116,917)
Balance, Shares at Sep. 30, 2020										19,590,998