Fair Value Measurements - Financial Assets Measured at Fair Value on Recurring Basis (FY) (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024	Dec. 31, 2023
Assets, Fair Value Disclosure [Abstract]
Total financial assets	$ 579,430	$ 114,716	$ 512,605
Fair Value, Recurring
Assets, Fair Value Disclosure [Abstract]
Adjusted Cost		112,154	511,132
Gross Unrealized Gains		0	14
Gross Unrealized Losses		0	0
Total financial assets		112,154	511,146
Fair Value, Recurring \| Prepaid Expenses and Other Current Assets
Assets, Fair Value Disclosure [Abstract]
Adjusted Cost			2,354
Gross Unrealized Gains			14
Gross Unrealized Losses			0
Total financial assets			2,368
Fair Value, Recurring \| Money market funds \| Cash and cash equivalents
Assets, Fair Value Disclosure [Abstract]
Adjusted Cost		2,411	87,258
Gross Unrealized Gains		0	0
Gross Unrealized Losses		0	0
Total financial assets		2,411	87,258
Fair Value, Recurring \| Money market funds \| Restricted cash and cash equivalents, current
Assets, Fair Value Disclosure [Abstract]
Adjusted Cost		24,185	42,940
Gross Unrealized Gains		0	0
Gross Unrealized Losses		0	0
Total financial assets		24,185	42,940
Fair Value, Recurring \| Money market funds \| Restricted cash and cash equivalents, non-current
Assets, Fair Value Disclosure [Abstract]
Adjusted Cost		56,250	206,846
Gross Unrealized Gains		0	0
Gross Unrealized Losses		0	0
Total financial assets		56,250	206,846
Fair Value, Recurring \| Certificates of deposit
Assets, Fair Value Disclosure [Abstract]
Adjusted Cost		29,308	171,734
Gross Unrealized Gains		0	0
Gross Unrealized Losses		0	0
Total financial assets		$ 29,308	$ 171,734

Fair value portion of asset recognized for present right to economic benefit.

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-Topic 820
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Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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-Topic 944
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