CONDENSED STATEMENTS OF PREFERRED STOCK AND STOCKHOLDERS’ EQUITY (DEFICIT) - USD ($) $ in Thousands	Preferred Stock Series A Preferred Stock	Preferred Stock Series B Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Total
Balance at the beginning at Dec. 31, 2018			$ 1	$ 352		$ (47,297)	$ (46,944)
Balance at the beginning (in shares) at Dec. 31, 2018			1,374,812
Balance at the beginning at Dec. 31, 2018	$ 71,000	$ 91,223
Balance at the beginning (in shares) at Dec. 31, 2018	68,181,819	56,828,851
Increase (Decrease) in Stockholders' Deficit
Stock based compensation				383			383
Issuance of common stock				4			4
Issuance of common stock (in shares)			4,697
Net loss						(6,155)	(6,155)
Balance at the end at Mar. 31, 2019			$ 1	739		(53,452)	(52,712)
Balance at the end (in shares) at Mar. 31, 2019			1,379,509
Balance at the end at Mar. 31, 2019	$ 71,000	$ 91,223
Balance at the end (in shares) at Mar. 31, 2019	68,181,819	56,828,851
Balance at the beginning at Dec. 31, 2018			$ 1	352		(47,297)	(46,944)
Balance at the beginning (in shares) at Dec. 31, 2018			1,374,812
Balance at the beginning at Dec. 31, 2018	$ 71,000	$ 91,223
Balance at the beginning (in shares) at Dec. 31, 2018	68,181,819	56,828,851
Increase (Decrease) in Stockholders' Deficit
Net loss							(22,810)
Balance at the end at Sep. 30, 2019			$ 23	240,791	$ (58)	(70,107)	170,649
Balance at the end (in shares) at Sep. 30, 2019			22,739,345
Balance at the beginning at Mar. 31, 2019			$ 1	739		(53,452)	(52,712)
Balance at the beginning (in shares) at Mar. 31, 2019			1,379,509
Balance at the beginning at Mar. 31, 2019	$ 71,000	$ 91,223
Balance at the beginning (in shares) at Mar. 31, 2019	68,181,819	56,828,851
Increase (Decrease) in Stockholders' Deficit
Stock based compensation				412			412
Issuance of common stock			$ 1	42			43
Issuance of common stock (in shares)			24,687
Initial public offering, net of issuance costs of $9.4M			$ 6	76,844			76,850
Initial public offering, net of issuance costs of $9.4M (in shares)			5,750,000
Conversion of preferred stock to common stock	$ (71,000)	$ (91,223)	$ 15	162,208			162,223
Conversion of preferred stock to common stock (in shares)	(68,181,819)	(56,828,851)	15,560,569
Net loss						(8,221)	(8,221)
Balance at the end at Jun. 30, 2019			$ 23	240,245		(61,673)	178,595
Balance at the end (in shares) at Jun. 30, 2019			22,714,765
Increase (Decrease) in Stockholders' Deficit
Stock based compensation				524			524
Issuance of common stock				22			22
Issuance of common stock (in shares)			24,580
Unrealized (loss) gain on marketable securities, net of tax $0					(58)		(58)
Net loss						(8,434)	(8,434)
Balance at the end at Sep. 30, 2019			$ 23	240,791	(58)	(70,107)	170,649
Balance at the end (in shares) at Sep. 30, 2019			22,739,345
Balance at the beginning at Dec. 31, 2019			$ 27	402,529	(38)	(81,034)	$ 321,484
Balance at the beginning (in shares) at Dec. 31, 2019			27,499,260				27,499,260
Increase (Decrease) in Stockholders' Deficit
Stock based compensation				1,008			$ 1,008
Issuance of common stock			$ 1	36			37
Issuance of common stock (in shares)			17,142
Unrealized (loss) gain on marketable securities, net of tax $0					(505)		(505)
Net loss						9,733	9,733
Balance at the end at Mar. 31, 2020			$ 28	403,573	(543)	(71,301)	331,757
Balance at the end (in shares) at Mar. 31, 2020			27,516,402
Balance at the beginning at Dec. 31, 2019			$ 27	402,529	(38)	(81,034)	$ 321,484
Balance at the beginning (in shares) at Dec. 31, 2019			27,499,260				27,499,260
Increase (Decrease) in Stockholders' Deficit
Net loss							$ (21,142)
Balance at the end at Sep. 30, 2020			$ 28	408,189	1,298	(102,176)	$ 307,339
Balance at the end (in shares) at Sep. 30, 2020			27,553,089				27,553,089
Balance at the beginning at Mar. 31, 2020			$ 28	403,573	(543)	(71,301)	$ 331,757
Balance at the beginning (in shares) at Mar. 31, 2020			27,516,402
Increase (Decrease) in Stockholders' Deficit
Stock based compensation				2,187			2,187
Issuance of common stock				3			3
Issuance of common stock (in shares)			4,248
Unrealized (loss) gain on marketable securities, net of tax $0					2,478		2,478
Net loss						(14,508)	(14,508)
Balance at the end at Jun. 30, 2020			$ 28	405,763	1,935	(85,809)	321,917
Balance at the end (in shares) at Jun. 30, 2020			27,520,650
Increase (Decrease) in Stockholders' Deficit
Stock based compensation				2,372			2,372
Issuance of common stock				54			54
Issuance of common stock (in shares)			32,439
Unrealized (loss) gain on marketable securities, net of tax $0					(637)		(637)
Net loss						(16,367)	(16,367)
Balance at the end at Sep. 30, 2020			$ 28	$ 408,189	$ 1,298	$ (102,176)	$ 307,339
Balance at the end (in shares) at Sep. 30, 2020			27,553,089				27,553,089