Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 108.3	$ 588.4
Restricted cash	4.5	0.0
Marketable securities	1,394.3	100.2
Accounts receivable	15.0	1.0
Other receivables	10.7	7.4
Prepaid expenses and other current assets	19.7	6.1
Total current assets	1,552.5	703.1
Property, equipment and leasehold improvements, net	12.7	12.3
Operating lease right of use assets	3.9	2.0
Collaboration contract asset and other assets	12.5	0.0
Total assets	1,581.6	717.4
Current liabilities:
Accounts payable	31.3	7.1
Accrued expenses	23.1	18.9
Deferred revenue	206.2	22.2
Current portion of operating lease liability	1.1	1.0
Total current liabilities	261.7	49.2
Deferred revenue	534.3	22.9
Long term debt	1.0	2.0
Operating lease liability	2.9	1.1
Total liabilities	799.9	75.2
Commitments and contingencies
Stockholders' equity:
Common stock, $0.001 par value, 53.0 and 48.5 shares issued and outstanding as of December 31, 2021 and 2020, respectively	0.0	0.0
Accumulated deficit	(682.9)	(491.9)
Additional paid-in capital	1,469.2	1,133.5
Accumulated other comprehensive (loss) income	(4.6)	0.6
Total stockholders' equity	781.7	642.2
Total liabilities and stockholders' equity	$ 1,581.6	$ 717.4