16. Supplemental Balance Sheet Information

Prepaid and Other Assets

As of March 31, 2025, the Company had $2.2 million of royalty-related assets remaining, recorded within the Prepaid and other current assets and other assets line items on the accompanying Consolidated Balance Sheets. The asset is being amortized over a 15-year period through September 2033 using an effective royalty rate.

A 15-year amortization period is the minimum expected life cycle of the current generation of product. The effective royalty rate is calculated as the prepaid royalty settlement divided by total projected microturbine system units over the 15-year amortization period. On a quarterly basis, the Company performs a re-forecast of microturbine system unit shipments to determine if an adjustment to the effective royalty rate is necessary and accordingly whether an impairment exists. The Company determined an impairment did not exist as of March 31, 2025 or 2024.

The current and long-term portions of prepaid royalties and prepaid and other assets were as follows (in thousands):

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