4. Condensed Consolidated Balance Sheets Details

Inventory, Net

Inventory consists of sub-assemblies, components, and raw materials, and work-in-process. Inventory not expected to be sold or consumed within one year, including inventory expected to be capitalized into property and equipment as cyclotron systems are completed, is classified as inventory, non-current. The composition of inventory, non-current as of June 30, 2026 and December 31, 2025 is as follows:

The Company maintains an allowance for inventory obsolescence to reduce the carrying value of slow-moving, obsolete, or damaged inventory to its estimated net realizable value. The allowance is based on historical write-offs, current inventory aging, and management’s assessment of future demand. No allowance for inventory obsolescence was recorded against inventory included in total current assets during the three and six months ended June 30, 2026 or June 30, 2025.

Activity in the allowance for inventory obsolescence, related solely to inventory, non-current was as follows:

No provision for inventory obsolescence was charged to cost of revenue for the three and six months ended June 30, 2025.

Prepaid Expenses and Other Current Assets

The composition of prepaid expenses and other current assets as of June 30, 2026 and December 31, 2025 is as follows:

Property and Equipment, Net

The composition of property and equipment, net as of June 30, 2026 and December 31, 2025 is as follows:

Construction in progress represents costs incurred for leasehold improvements and a cyclotron system that were not substantially complete and ready for their intended use as of June 30, 2026 and December 31, 2025. Construction in progress includes direct costs of acquisition, installation, and other expenditures necessary to bring the assets to the condition necessary for their intended use. No depreciation is recorded on construction in progress until the related assets are substantially complete and placed into service.

Depreciation expense was $0.9 and $0.8 million for the three months ended June 30, 2026 and 2025, respectively, and $1.8 and $1.6 million for the six months ended June 30, 2026 and 2025, respectively.

Accrued Expenses and Other Current Liabilities

The composition of accrued expenses and other current liabilities as of June 30, 2026 and December 31, 2025 is as follows:

Other Non-Current Liabilities

The composition of other non-current liabilities as of June 30, 2026 and December 31, 2025 is as follows: