Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net loss	$ (72,273)	$ (74,808)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization expense	147	720
Stock-based compensation expense	11,686	6,017
Noncash consideration received from a customer		(808)
Noncash portion of acquired in-process research and development		44,813
Gain on disposal of long-lived assets		(7,493)
Change in fair value of CVR liability	(343)	1,025
Changes in operating assets and liabilities:
Accounts receivable		2,000
Prepaid expenses and other current assets	(227)	(1,470)
Operating lease, right-of-use asset	1,844	670
Other assets	(3,727)	427
Accounts payable	2,751	(2,451)
Accrued expenses and other current liabilities	3,431	(2,352)
Operating lease liability	(2,052)	(825)
Deferred revenue		(1,315)
Net cash used in operating activities	(58,763)	(35,850)
Cash flows from investing activities:
Purchases of property and equipment	(1,719)
Proceeds from sale of property and equipment		320
Proceeds from sale of BOXR Platform assets		8,100
Net cash (used in) provided by investing activities	(1,719)	8,420
Cash flows from financing activities:
Proceeds from the issuance of Series A non-voting convertible preferred stock, net of issuance costs of $5,493		98,907
Proceeds from issuance of common stock to LPC		25,000
Proceeds from issuance of common stock under ATM, net of issuance costs of $1,229	38,006
Proceeds from issuance of common stock in underwritten public offering, net of offering costs of $7,271		107,729
Proceeds from issuance of common stock upon stock option exercises	24	512
Proceeds from issuance of stock from employee stock purchase plan	31	48
Payments to CVR Holders	(85)
Net cash provided by financing activities	37,976	232,196
Net (decrease) increase in cash, cash equivalents and restricted cash	(22,506)	204,766
Cash, cash equivalents and restricted cash at beginning of period	243,445	38,679
Cash, cash equivalents and restricted cash at end of period	220,939	243,445
Supplemental disclosure of noncash investing and financing information:
Conversion of Series A non-voting convertible preferred stock into common stock	25,481	27,351
Issuance of common shares in partial settlement of CVR liability	$ 2,043	$ 6,944