Quarterly Financial Data (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating expenses:
Research and development	$ 70,742	$ 68,271	$ 58,499	$ 47,929	$ 52,889	$ 54,873	$ 51,632	$ 45,770	$ 245,441	$ 205,164	$ 184,809
General and administrative	14,557	12,141	11,774	9,658	11,712	8,287	10,110	7,209	48,130	37,318	21,864
Total operating expenses	85,299	80,412	70,273	57,587	64,601	63,160	61,742	52,979	293,571	242,482	206,673
Loss from operations	(85,299)	(80,412)	(70,273)	(57,587)	(64,601)	(63,160)	(61,742)	(52,979)	(293,571)	(242,482)	(206,673)
Interest income	1,076	717	323	69	52	60	91	160
Interest expense	(1,682)	(1,502)	(780)	0	0	0	0	0	(3,964)	0	0
Other income	0	0	0	0	0	0	0	273	0	273	100
Net loss	$ (85,905)	$ (81,197)	$ (70,730)	$ (57,518)	$ (64,549)	$ (63,100)	$ (61,651)	$ (52,546)	$ (295,350)	$ (241,846)	$ (202,244)
Net loss per common share, Basic	$ (4.98)	$ (4.75)	$ (4.14)	$ (3.36)	$ (3.78)	$ (3.79)	$ (3.72)	$ (3.32)	$ (17.23)	$ (14.63)	$ (13.09)
Net loss per common share, Diluted	$ (4.98)	$ (4.75)	$ (4.14)	$ (3.36)	$ (3.78)	$ (3.79)	$ (3.72)	$ (3.32)	$ (17.23)	$ (14.63)	$ (13.09)
Weighted average number of common shares outstanding, Basic	17,237,517	17,103,395	17,103,395	17,103,395	17,074,543	16,639,776	16,571,322	15,840,401	17,137,201	16,535,188	15,446,638
Weighted average number of common shares outstanding, Diluted	17,237,517	17,103,395	17,103,395	17,103,395	17,074,543	16,639,776	16,571,322	15,840,401	17,137,201	16,535,188	15,446,638