Condensed Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities:
Net loss	$ (38,986)	$ (21,220)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	582	347
Stock-based compensation expense	4,099	1,865
Amortization of operating right-of-use assets	1,787	180
Net amortization of premiums on investments	321	151
Loss on disposal of fixed assets	44
Asset impairment charges	57
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	2,791	(557)
Other assets	(1,577)	(441)
Operating lease liabilities	5,619	(105)
Accounts payable	(1,933)	2,185
Accrued compensation	(2,185)	723
Accrued manufacturing expenses	2,416	2,525
Accrued expenses	(737)	1,142
Net cash used in operating activities	(27,702)	(13,205)
Cash flows from investing activities:
Purchases of property and equipment	(2,920)	(1,246)
Proceeds from sale of property and equipment	7
Purchases of investments	(6,972)	(172,145)
Maturities of investments	59,551
Net cash provided by (used in) investing activities	49,666	(173,391)
Cash flows from financing activities:
Proceeds from follow-on public offering, net of underwriters' commissions and discounts	107,622
Proceeds from exercise of common stock options	282	487
Proceeds from issuance of common stock related to at-the-market offering, net of issuance costs	3,115
Net cash provided by financing activities	111,019	487
Effect of exchange rate changes on cash and cash equivalents	(227)	(281)
Net increase (decrease) in cash, cash equivalents and restricted cash	132,756	(186,390)
Cash, cash equivalents and restricted cash, beginning of period	69,856	386,200
Cash, cash equivalents and restricted cash, end of period	202,612	199,810
Supplemental disclosures of non-cash investing and financing activities:
Purchases of property and equipment recorded in accounts payable and accrued expenses	664	$ 1,537
Deferred offering costs included in accounts payable and accrued expenses	$ 23