Condensed Consolidated Balance Sheets (unaudited) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Current assets:
Cash and cash equivalents	$ 114.9	$ 100.5
Marketable securities	746.3	938.9
Accounts receivable	0.5	5.7
Other receivables	10.6	8.0
Prepaid expenses and other current assets	17.2	14.2
Total current assets	889.5	1,067.3
Property, equipment and leasehold improvements, net	6.1	7.0
Operating lease right-of-use assets	9.3	9.0
Collaboration contract asset and other assets	4.4	8.1
Total assets	909.3	1,091.4
Current liabilities:
Accounts payable and accrued liabilities	53.1	71.8
Deferred revenue	102.9	156.2
Current portion of operating lease liabilities	1.8	1.8
Total current liabilities	157.8	229.8
Deferred revenue	134.1	292.0
Long-term debt	0.5	0.6
Operating lease liabilities	7.6	7.3
Total liabilities	300.0	529.7
Commitments and Contingencies (Note 13)
Stockholders’ equity:
Preferred stock, $0.001 par value, zero shares issued and outstanding as of June 30, 2025 and December 31, 2024, respectively	0.0	0.0
Common stock, $0.001 par value; 73.2 and 68.8 shares issued and outstanding as of June 30, 2025 and December 31, 2024, respectively	0.1	0.1
Accumulated deficit	(1,509.9)	(1,531.6)
Additional paid-in capital	2,118.1	2,092.2
Accumulated other comprehensive income	1.0	1.0
Total stockholders’ equity	609.3	561.7
Total liabilities and stockholders’ equity	$ 909.3	$ 1,091.4