CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating activities
Net loss	$ (36,684)	$ (13,075)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	7,873	3,172
Depreciation and amortization	687	485
Premiums and discounts on available-for-sale marketable securities	1,175	1,279
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(586)	(816)
Receivables—due from related parties		(279)
Contract asset—due from related parties	(1,128)	(22)
Accounts payable	(1,437)	4,150
Accrued expenses and other current liabilities	(2,278)	235
Deferred revenue	(8,359)	(17,822)
Operating lease right-of-use assets	119	95
Operating lease liabilities	(227)	(368)
Other assets and liabilities	550	143
Net cash (used in) provided by operating activities	(40,295)	(22,823)
Investing activities
Purchase of property and equipment, net	(482)	(164)
Purchases of investments	(80,118)	(16,013)
Maturities of investments	106,463	60,500
Net cash used in investing activities	25,863	44,323
Financing activities
Proceeds from stock option exercises	449	1,147
Payments of offering costs in connection with initial public offering		(397)
Payments on finance leases	(264)	(155)
Net cash provided by financing activities	185	595
Net increase (decrease) in cash, cash equivalents and restricted cash	(14,247)	22,095
Cash, cash equivalents and restricted cash at beginning of period	54,092	32,593
Cash, cash equivalents and restricted cash at end of period	39,845	54,688
Supplemental disclosure of cash flow activities
Cash paid for interest	46	24
Supplemental disclosure of noncash investing and financing activities
Property and equipment purchases included in accounts payable and accrued expenses	126	259
Supplemental disclosure of noncash operating activities
Cash and cash equivalents	33,733	53,098
Restricted cash	6,112	1,590
Total cash, cash equivalents, and restricted cash	$ 39,845	$ 54,688